Volume 8, No. 4,33-48 Winter 1993-1994
Table of Contents

ASA Scientific Presentations Showcase Safety
ASA Tape on OR Fires Being Distributed
Editorial: The State of the Foundation
Letters to the Editor
Dryden Research Fund for Infection Study Set Up in APSF
ASA Exhibits Show Slight Safety Shift
APSF Awards Research Grants for 1994
New Standards Focus on Piped Medical Gas Systems:  Part of a Series on "Out of Sight, Out of Mind: Behind the Wall"
MHAUS Acts to Keep Hyperthermia Patients Safe
In My Opinion: A Debate

ASA Scientific Presentations Showcase Safety

by David M. Gaba, M.D., Gerald L. Zeitlin, M.D., Arthur I.L. Schneider, M.D., and Jeffrey B. Cooper, Ph.D.

Patient safety again figured prominently as a theme of the scientific sessions of the Annual Meeting of the American Society of Anesthesiologists October 9-13 in Washington, D.C. In six scientific sessions, there were 83 individual scientific presentations.

One session featured a frequent topic of discussion in the APSF Newsletter, pulmonary edema, which can occur as a complication of anesthesia and surgery without mismanagement of fluid administration. Dr. M. Maroof and colleagues from Riyadh, Saudi Arabia, reported on postoperative pulmonary edema in healthy (ASA I or 11), young patients having elective surgery. The cases were identified by the retrospective review of records. Excessive fluid administration was not found. The authors suggested that upper airway obstruction and negative intrathoracic pressure might have been involved in development of pulmonary edema.

Opinions, Pressures

Two papers discussed the practices of anesthesiologists in the complex world of medicine. Dr. K. Poterack from Wilford Hall Medical Center presented case vignettes involving controversial management issues such as the patient with an .open-eye' but a full stomach. Respondents were asked to state whether the actions described were .acceptable' or not, and whether they would 'do this in your own practice." They found that for six out of 11 vignettes there was a marked difference between what respondents felt was acceptable versus what they believed they would do.

Dr. S. Howard and associates from Stanford University and the Palo Alto VAMC surveyed California anesthesiologists concerning their attitudes about and experiences with production pressure in the work environment (a topic also discussed in several recent articles in the APSF Newsletter). Their survey controlled for selection bias of respondents. They found that many anesthesiologists reported internal pressures they put on themselves to please surgeons and avoid delays. They also reported overt external pressure from surgeons not to cancel cases, and to avoid delays. Nearly half of respondents had witnessed unsafe actions resulting from such pressures, although the effect on patient outcome is unknown. The authors suggested that the anesthesiology profession needs to confront these issues openly and find ways to prevent such pressures from causing preventable adverse outcomes for patients.

Lipid Vehicle Risk?

The underlying science related to potential risks of nosocomial infection from bacterial contamination in the lipid vehicle of propofol was studied by Dr. P. Langevin and associates from the University of Florida, Gainesville. They studied the distribution of bacteria in body tissues of rabbits inoculated with S. aureus suspended either in intralipid or buffer. The time course of bacterial distributor in blood did not differ between the groups, but distribution to other tissues was markedly different. The authors suggest that bacterial growth in Intralipid at room temperature is unlikely to explain nosocomial infection, but they propose that suspension in Intralipid micelles may allow bacteria to escape destruction in the rediculo endothelial system.

Pain Service Dangers

In a report from the Brigham and Women's Hospital in Boston, Dr. H. Flanagan and his colleagues from an active acute pain service illustrated the concept of 'total quality management' while improving patient safety. They describe 10 critical incidents (Cls) resulting from the use of an ordinary intravenous infusion pump for continuous postoperative narcotic/local anesthetic infusions. Their poster illustrated dramatically how the physical features of the pump allowed the Cls to occur. A few examples include:

* family member increased the infusion rate;

* patient increased the flow rate to 10 times the infusion rate ordered;

* two instances when the pump was mistaken for an IV and an excessive infusion rate was set.

Other fascinating mishaps were: after a patient had undergone an MRI examination an epidural cassette was snapped into an IV pump -and vice versa; aminophylline was piggybacked into the epidural infusate tubing in another patient.

Modifications to the pump did not help. Detente pins to limit maximum flow rate were added and the pumps were painted bright orange. Human ingenuity and muscle power overcame these prophylactic maneuvers and there were two more critical incidents.

Flanagan et al. conclude by listing key design specifications in designing purpose-built epidural pumps:

* the drug reservoir must be enclosed in a locked transparent receptacle;

*software must control the maximum possible flow rate;

* software must prevent tampering with the rate setting;

* the pump cassette must be de-aired easily but not allow gravity flow;

* the infusion tubing must have no tempting injection ports;

* the infusion tubing must be colored or striped.

The data that Flanagan et al. gathered and analyzed was necessary to persuade their hospital's administrators to purchase new equipment; this type of activity is clearly important given the current fiscal climate.

CVP Complications

Drs. R. Blackshear and N. Gravenstein of the University of Florida neatly demonstrated the necessary condition leading to the excess of superior vena cava perforations previously reported in the literature with left-sided central vein cannulation when compared to the use of the right side.

They reviewed retrospectively the records and chest x-rays of 200 patients. There were 50 in each of the following groups: right-sided internal jugular (IJ) and subclavian, and left-sided internal jugular and subclavian. They also limited the cases studied to those in which the tip of the catheter could be seen to he in the superior vena cava (SVC) on the chest x-ray. Most importantly, they measured the angle of incidence of the catheter to the wall of the SVC using the vertebral column as a zero degree reference point. In summary, they found significantly greater angles of incidence associated with left-sided insertions and in particular with left sided IJ insertions. Their observations led them to recommend avoidance of left-sided insertions whenever possible and the use of chest x-rays to assure that the catheter tip lies at an angle of incidence less than 40 degrees to the wall of the SVC.

Nerve Injuries

Drs. M. Werner and J. Martin of the Mayo Clinic performed a retrospective chart review of nearly 200,000 patients who underwent operations historically performed with the patient in the lithotomy position. They identified 55 patients with a persistent neuropathy of the lower extremities. They defined this as a motor neuropathy lasting more than three months. They identified three major risk factors: thin body habitus, smoking within 30 days of the procedure and lithotomy position maintained for more than four hours. Regional anesthesia was not associated with an increased risk of neuropathy. These observations might explain the findings of Kroll et al. from the ASA Closed Claim Study database, that only 28% of lumbosacral nerve root injuries leading to claims had an identifiable mechanism that was anesthesia-related.

In a return to last year's theme of the safety of the anesthesia provider, Dr. M. Swanson and colleagues demonstrated that latex allergens can take off and become airborne in O.R. suites. The potential for greatest exposure occurs during glove manipulations and since anesthesia personnel change their gloves frequently (or are supposed to), their exposure is greater than that for other personnel.

Airway Ideas

Several papers relating to patient safety were presented at the session on Airways Complication and Management. Four papers related to laryngeal mask airways. Dr. D. Reinhart of the University of Utah began the session by comparing the effects of laryngeal mask airways (LMAS) and endotracheal tubes in a series of 36 propofol and thiopental anesthetized patients. Significantly less increase in systolic, mean and diastolic blood pressure, and heart rate were seen during airway manipulation with the LMA series. Also, significantly fewer patients in the LMA group had post anesthetic coughs or sore throats. No regurgitation was noted in either group although one LMA group patient developed laryngospasm. Dr. Reinhart suggested that LMAs may be useful in patients in whom cardiovascular stimulation should be avoided.

In a second report, Dr. Reinhart described a comparison of endotracheal tube and LMA placement by a group of paramedical personnel. A group of 10 paramedics, respiratory therapists, and nurses, all with some experience in endotracheal intubation, watched a 20 minute training film on LMA placement. Each recruit then attempted to place both an ETT and a LMA in an anesthetized patient. Three attempts were allowed before failure was declared. The LMA was placed successfully in each case on the first attempt in an average of 38 seconds. ETT was placed successfully in three (of 10) cases in an average of 237 seconds. Subjects scored LMA placement as being less difficult. Dr. Reinhart concluded that LMA may be an acceptable alternative to endotracheal intubation by paramedical personnel in difficult circumstances.

Dr. T. Owens and colleagues from St. Vincent's Hospital in Dublin and the University of Texas at Galveston described their study in which 55 anesthetized patients were studied for evidence of gastroesophageal reflux during either face mask or LMA airway management. Reflux was assessed with small pH electrodes placed in the esophagus before induction and maintained in place during anesthesia. A significantly higher percentage of LMA patients was found to have episodes of pH < 4.0 in the distal esophagus, 57 percent with LMA and 22 percent with mask airways. Continuous monitoring of pH allowed the time of reflux to be recorded as well; LMA group reflux was found intraoperatively, during patient position change, and during recovery more often than was face mask group reflux.

A study on the resistance of the LMA to laser damage was presented by Drs. J. Pennant, N. Gajraj, and J. Miller from the University of Texas Southwestern Medical Center in Dallas. Because of previous reports of resistance of LMAs to low power tunable dye lasers, they investigated LMA resistance to the higher power carbon dioxide laser.

Instantaneous LMA shaft perforation and ignition were achieved with the laser set at 10 and 50 W. A one W beam required 60 seconds to perforate and ignite the LMA shaft. LMA cuff perforation was also achieved at all three settings, although it required 10 seconds at one W power. The silicone rubber LMA tubes produced less smoke and flaming than polyvinyl chloride tubes similarly tested. The authors felt that LMA could not be recommended for use in an unmodified form for laser treatment of the upper airway and that further studies on protecting LMAs from laser energy should be undertaken.

An analysis of airway management by anesthesiologists was presented by Drs. M. Mascia and M. Matjasko from the University of Maryland. They used a specially designed data collection form to collect information about the 613 emergency airway consultations done by their department from July 1991 until June 1992. Most patients, 61%, were males which might be explained by the fact that 23% of encounters took place in the emergency room, while 45% occurred in the ICU, and 6% in step down units. Acute respiratory failure was the most common reason for consultation while failed extubation, trauma, codes, and neurologic compromise were also frequently encountered. Complications were recorded in 18% of intubations. The complication rate of intubations done using drugs was significantly higher than the rate when intubation was accomplished in awake patients. Study data were useful in determining when junior residents might be given responsibility to attend codes alone.

Balloons and Bulbs

Two new devices were described. The first, a nasogastric balloon tube designed to prevent regurgitation and aspiration, was described by Drs. N. Roewer and J. Schulte am Esch from University Hospital Eppendorf, Hamburg, Germany. The tube, which resembles a nasogastric tube with a large balloon at the distal end, is inserted into the stomach prior to anesthesia, the balloon is inflated, and traction is applied to the tube. Three series of tests with the tube were described. In the first, anesthetized pigs were fitted with the tube and balloon while vigorous mechanical and chemical efforts were made to force the pigs to regurgitate. In the second series, volunteers ingested mineral water and were then fitted with tubes and inflated balloons and efforts were again made to induce regurgitation. Finally, a series of emergency patients was fitted with tubes and balloons prior to induction of anesthesia. In all cases, regurgitation was prevented.

The use of a self-inflating bulb in detecting esophageal intubation was further investigated and reported by Dr. Y. Waifai, and associates from the Illinois Masonic Medical Center in Chicago. The bulb, which now must be home-made, consists of an irrigating syringe bulb fitted to an adapter which allows it to be attached to the connector of an endotracheal tube. It has been shown that the bulb, if deflated and attached to a properly positioned endotracheal tube with the cuff inflated, will nearly always quickly reinflate when released and that it will nearly always not reinflate if the endotracheal tube is in the esophagus. The question was whether this was also true if the tube cuff was deflated. Endotracheal tubes were placed in both the esophagus and trachea in 30 anesthetized patients. All cuffs were deflated. In all cases the bulb instantaneously reinflated when attached to the tracheal tube and did not reinflate when attached to the esophageal tube. The authors conclude that the selfinflating bulb reliably distinguishes tracheal from esophageal intubations even when the tube cuff is deflated.

Dirty Handles

Drs. R. Morrell, D. Crews, D. Ririe, and R. James from Wake Forest University Medical Center reported on a study in which they looked for blood contamination of 38 laryngoscope handles and blades that had been routinely cleaned and returned to service. The handles and blades were rinsed with 10 ml of saline and two drops of the rinse were tested using a Hemoccult Sensa occult blood slide. Nineteen handles (50%) and four blades (10%) tested positively for occult blood. The authors did no bacterial or viral cultures but do suggest that disposable laryngoscope covers, disposable laryngoscopes, or improved cleaning protocols may become necessary to address this apparent problem of equipment contamination.

Lost Tubes

A paper entitled "Anesthesia and Unplanned Extubation" was presented by Drs. S. Shields, B. Harrison and R. MacKenzie of the Mayo Clinic. These authors reviewed their hospital data files and identified 76 patients (or 227,699) in whom an unplanned extubation had occurred during surgery from 1985 to 1992. Forty-three of these extubations occurred in pediatric patients (1:411), and 33 in adults (1:6,364). Twelve percent of extubations occurred during tonsillectomies and a total of 46% during head and neck surgery. A variety of methods had been used to secure the tubes. The study points out the need for extra vigilance in securing and monitoring endotracheal tubes in head and neck surgery, particularly when the patient is a child.

Dr. A. Ovassapian, et al. of the Northwestern University Medical School and the Lakeside VA Medical Center in Chicago presented a report on the length of the upper airway in adult male patients. Fiberoptic bronchoscopy was used to measure the distance from the incisors to the vocal cords and from the incisors to the carina in 30 anesthetized patients. Attempts were made to correlate these measurements with patient age, weight, and external body measurements including distance from the tip of xiphoid to cricoid ring, length of the middle finger, and mandibular circumference. Although there was statistical correlation between age and the bronchoscope measurements, the authors concluded that true airway lengths were poorly predicted by the external measurements and that placement of endotracheal tubes to a fixed depth should be discouraged.

Intubation Predictions

The problem of predicting difficulty of endotracheal intubation was addressed in a study by Drs. S. Keramati, M. Lewis, and J. Benumof of the University of California in San Diego. Oropharyngeal class (I pillars and uvula, II uvula, III base of uvula and IV soft palate alone) was determined preoperatively in a variety of neck positions with and without phonation in 213 adult patients. The distance between the larynx and mandible was also measured in these patients in a similar variety of conditions in order to estimate mandibular space. The best prediction of subsequent difficult intubation using oropharyngeal class was found when patients were examined sitting, phonating and with neck and tongue extended. The best mandibular space prediction came from measuring from the inside of the mandible to either the hyoid bone or the thyroid cartilage in patients in the sniffing or neck extended position. These measurements allowed predicting difficult intubation with about the sensitivity of other published studies. The authors emphasize that other factors such as neck flexibility and soft tissue mobility also markedly affect the difficulty of intubation.

Drs. S. Samra and F. Guinto from the University of Michigan gave a progress report on an APSF sponsored study in which MRI scans and x-rays of 20 patients who had been difficult intubations were examined in an effort to find physical identifiers of difficult intubation. All subjects, and 20 matched controls, had lateral MRI scans of the neck and two lateral x-rays of the neck, one exposed for bone, the other for soft tissue. None of the skeletal measurements revealed a significant difference between the two groups. Dr. Samra reported that a seemingly positive correlation between MRI soft tissue measurements and difficult laryngoscopy had not been up to repeated examination. While examination of the films continues, a reliable soft tissue or skeletal indicator of the difficulty of intubation has not yet been identified in this study.

A general theme emerged from a set of presentations in the patient safety poster/discussion session: Clinicians have behaviors that may be less than optimally safe; changing those behaviors isn't easy, but it can be done. Patient behavior can also be altered. Several posters demonstrated the many ways in which realistic simulators are now being used to measure and alter behavior.

Dr. R. Botney and colleagues from Stanford studied 'fixation error," using a set of videotapes taken during a course in Anesthesia Crisis Resource Management at another institution. Subjects had been presented two different, simultaneous events during the training, which used the realistic anesthesia simulator developed by the Stanford group. One of the problems was a simple failure of a capnometer; the other the more serious case of a fully opened vaporizer, concealed from view by printout from the NIBP monitor. Although most of the 18 subjects eventually discovered the more serious problem, five did not. The study demonstrates that fixation error is a real phenomena that can be measured.

In another study using the same group and simulator environment, Dr. Botney described how subjects reacted to a simulated, unexpected loss of oxygen pipeline pressure. Review of the taped sessions revealed the kinds of deficiencies that occur when reacting to a critical event. The responses of the subjects varied considerably; in general they did not have a well-formulated plan. Fortunately, most managed to ventilate the 'patient' adequately, although sub-optimally. Few instituted the most appropriate measures. The difficulty of urgently replacing an oxygen cylinder was apparent.

Dr. V. Chopra and colleagues at the University Hospital Leiden in the Netherlands, using their realistic simulator environment, demonstrated that practicing in a simulator seems to be effective at improving performance. Using a 3-phase experimental design that incorporated incidents of either malignant hyperthermia(MH) or anaphylactic shock(AS), the study measured changes in performance according to a standardized scale. Both groups had simulator training in AS, but only one group had simulator training in MH. Here again, the value of simulation was illustrated for measuring and, in this case, improving performance. The trainees with simulator training in MH appeared to perform better on that event than did the control group.

Regarding the design of simulators, Dr. W. van Meurs, representing the group that developed the Gainesville Anesthesia Simulator, described the physiologic model that has now been incorporated into the system and which drives the responses of the manikin. The model is capable of mimicking most aspects of the manikin's physiology, thus allowing for a large assortment of event simulations. He explained how such model-driven simulators have great advantage over 'script" driven systems. That " is the trend in realistic simulator design was clear: the two other realistic simulators represented in this group of abstracts also have a model-controlled design philosophy.

Those who experience training in a realistic simulator generally seem to perceive that the experience is valuable and that most clinicians should be provided such training periodically. These findings were from post-course evaluations administered by a group from the Harvard Medical School Anesthesia Departments who instructed subjects in ACRM using the CASE 2.0 simulator, which had been transported to their institution. Dr. R. Holzman presented the study, which also demonstrated that the simulator environment is transferable to a venue outside of the one in which it was developed.

Several abstracts addressed aspects of resident training using techniques other than realistic simulation. Drs. M. Olympio and M. Goldstein of Wake Forest University illustrated how feedback of videotaped performance can be effective in improving performance and altering practice. Using the FDA recommended guidelines for anesthesia machine check-out and other ASA-developed practice guidelines, the study compared performance of two groups of residents-one with and one without feedback about their performance in the form of observation and critique of a videotape of their activities during an actual anesthetic. The group with feedback showed substantial improvement over the control group.

Dr. T. Cutter and others at the University of Chicago measured the factors that affect residents' perceptions of the value of their educational experience. Interactions between attendings and residents were observed during 130 procedures and residents were surveyed for their perception of the value of various characteristics of their teachers and the educational environment. It appears that what an attending 'says' is perceived as being more valuable than what an attending 'does'. Dr. Cutter remarked during the discussion presentation that residents most appreciated being challenged by their teachers to consider 'what if' situations.

Dr. J. Tome, presenting for herself and Dr. 1. Cohen of the Children's Hospital of Pittsburgh, reported success at teaching third-year medical students skills in mask airway technique. This was despite surprising deficiencies in ability and understanding of airway management prior to the course even though all had taken Basic Life Support and introductory airway skills courses. The study also demonstrated that clinical skills can be measured via OSCES, Objective Structured Clinical Examinations.

Dr. W. Foster of the University of Texas Medical Center, Dallas, reported that patients remember more when instructed by a videotape of preoperative information versus having the same kinds of preoperative information given by an anesthesiologist and supplemented by written material. The study suggests that an audiovisual program may be effective in improving compliance with preoperative instructions, although specific study of that question was not attempted.

Finally, Dr. R. Prielipp reported on the remarkably low utilization of the esophageal stethoscope by most anesthetists who were observed in four different medical centers. fin 520 recorded observations, overall listening frequency was 28%. Only CRNA students seemed to listen to the stethoscope with regularity (75% of observations). Dr. Prielipp and his colleagues shared their concern over the substitution of other forms of monitoring for the esophageal stethoscope.

Dr. Gaba is from Stanford University; Dr. Zeitlin is from the Brigham and Women's Hospital, Harvard Medical School; Dr. Schneider is at Hershey Medical Center, Hershey, PA; and Dr. Cooper is at the Massachusetts General Hospital and Harvard.

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ASA Tape on OR Fires Being Distributed

by Ellison C. Pierce, Jr., M.D.

'Fire in the Operating Room,' ASA funded Videotape No. 20, is now available. Burroughs-Wellcome began distribution of the tape in October 1993.

This videotape details the origin, prevention and management of fires in the operating room. Paul F. Leonard, BSEE, M.D., and Gerald L. Wolf, M.D., narrators, emphasize O.R. team training and vigilance in fire prevention; the correct use of O.R. surgical equipment, alertness to other conditions contributory to fire ignition, and the right choice and method for fire extinguishment based upon the fire ignition source. Although all O.R. fires are devastating, those fed by oxygen-enriched environments pose the greatest danger. Anesthesia providers, therefore, should be on constant alert, should have a protocol for airway fires and must be forearmed with an immediate and total response to prevent patient injury, proceed with patient evacuation speedily and extinguish fires correctly.

The film, prepared by the ASA Committee on Patient Safety and Risk Management, was scripted by GWF Associates. David Eric Lees, M.D., Paul F. Leonard, BSEE, M.D., Gerald L. Wolf, M.D., and John M. Brunner, M.D., served as consultants.

The next videotape, No. 21, 'An Anesthetic Catastrophe', completed and in the editing phase, will be available in February 1994. Burroughs Wellcome will again distribute the tape.

Dr. Pierce is President of the Anesthesia Patient Safety Foundation (APSF) and Executive Producer of the ASA Patient Safety Videotape Series. All tapes in the ASA Patient Safety Videotape Series, many of which are still available, are distributed by local Burroughs Wellcome representatives.

Videotapes produced in this series include:

Cassette A

1. ASA Series Overview

2. Preventing Disconnection in the Breathing circuit

3. Machine Checkout

Cassette B

4. Anesthesia Record Keeping 5. Human Error

6. Adverse Events

Cassette C

7. Monitoring with the Six Senses

8. Monitoring with Instruments

9. Anesthesia Equipment Service

10. Margin of Safety-Monitoring the Neuromuscular junction

11. Emergence: Patient Safety in the Postanesthesia Care Unit

12. The Impaired Practitioner

13. Safety in Obstetrical Anesthesia

14. Anatomy of an Anesthesia Machine

15. The Difficult Airway-Part I-Algorithm

16. The Difficult Airway, Part II: Management The Cricothyroid Membrane

17. Central Venous Catheters

18. Infection Control in Anesthesiology

19. The Difficult Airway, Part Ill-Fiberoptic Intubation

20. Fire in the Operating Room

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Editorial: The State of the Foundation

The APSF, in its eighth year, remains very active. Perhaps the most significant occurrence during the year was the establishment of the Foundation's independent Executive Office with E. S. (Rick) Siker, M.D., as the Executive Director and Ms. Michelle Turkowski as Administrative Assistant. Dr. Siker has solidified activities in a major effort to reduce administrative costs, to increase outside contributions, and to fine-tune a smooth running machine.

The Newsletter continues to be a most successful undertaking, with numerous comments given me about the value of its material. Activities in the patient safety research arena, likewise, continue in a vigorous manner. Results of the funded grants have been summarized in the Newsletter, as they proceed. In addition, the year included the establishment of the APSF "Young Investigator's Award."

Simulators Grow

There has been additional growth in development of simulators for education and training in anesthesia. The two major simulators, from Gainesville and Stanford, have become available commercially; centers are planned in Boston at Harvard and New York City at Mt. Sinai. Worldwide interest in anesthesia patient safety continues unabated. The Australian Anesthesia Patient Safety Foundation plays a major role. In the UK efforts to establish a Foundation are well underway.

Parallel ASA Growth

Other activities of major importance include the ever-expanding numbers of closed claims evaluated in the ASA Closed Claims Project, the completion of the first two Practice Parameters by the ASA, (the Difficult Airway and Pulmonary Artery Catheterization), the revision of the FDA Preanesthesia Apparatus Checkout Recommendations, and the increase in the number of presentations in anesthesia patient safety at the ASA Annual Meeting.

Lastly, the APSF is in the process of awarding commendation plaques to the Corporate Donors who have been Grand Patrons for some time, including Burroughs-Wellcome, BOC Healthcare, Puritan-Bennett, and Zenecca Pharmaceuticals Group (ICI).

The APSF Executive Committee, in its efforts to provide a broad-based consensus in anesthesia patient safety, welcomes comments and suggestions from anesthesiologists and other interested parties worldwide.

Ellison C. Pierce, Jr., M.D.

President, Anesthesia Patient Safety Foundation

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Letter to the Editor:

IV Line Check Valve Prevents Backward Flow and Danger from "A Little K+"

To the Editor

I read with interest the report entitled 'What Harm Can There Be In Giving A Little Potassium?' in the APSF Newsletter, Vol. 8, No.2, p. 20. 1 agree with the recommendation of Drs. Gaba and Howard about attaching the potassium-containing solution as close to the patient as possible on the main intravenous line and agree that the use of a mechanical delivery device would not necessarily prevent a mishap similar to the one described. However, use of main intravenous lines incorporating non-return valves would definitely prevent such a problem from occurring. We routinely employ such I.V. lines in our hospital and I believe they are generally widely used.

Brendan Garry, M.D. Staff Anesthesiologist

New England Medical Center Boston, MA

Prevention Solves Epidural Disconnect Problem

To the Editor

A letter to the editor in the Summer 1993 APSF Newsletter regarding the controversy about reconnecting a disconnected epidural catheter recommended that 'the most prudent course of action to prevent catheter related infection is to select an epidural catheter hub/connection with the least likelihood of disconnect, to take all precautions to prevent disconnect and remove or replace any catheters that do become disconnected.' In our busy practice, disconnected catheters became an everyday nuisance and a major inconvenience, taking away from our other more important clinical duties. All catheter and adapter assemblies can become disconnected. Some fit better than others, but often at a much greater per unit cost.

An inexpensive method for providing a secure catheter adapter connection is to fold a simple piece of 2-inch tape over on itself sandwiching a loop of the catheter and the adapter as noted below. The tape must cover the distal portion of the adapter leaving only the male end to connect to a syringe or luer-lock catheter. Since we instituted this taping method, we have not had any disconnections and thus no need to consider any sterilizing process and, even better, no time wasted attending to or replacing these catheters. It is difficult to justify purchasing an expensive adapter when a simple piece of tape will do the job.

Stephen F. Kennedy, M.D. Director, Pain Service Fairfax Hospital

Falls Church, VA

Reader of Question on "Older" Anesthesiologists Has Concerns for Problems of Youth

Only Time May Be Cure

To the Editor

Dr. Travis's communication raises a parallel problem of "What to do with younger anesthesiologists?" Admittedly, this problem will (in most cases) be mitigated by the passage of time, but it can be at best irksome and at worst dangerous.

If the suggested questionnaire were modified to include the second problem, these collected data could be made available to training programs for remedial action. The problem can be broken down into five areas:

1. utilization/length of stay

2. materials management

3. professional relations

4. clinical skills

5. productivity

1. Cases are sometimes canceled for questionable reasons but this is documented in such a way that a more experienced colleague is precluded

from proceeding. Extra days in the hospital result.

2. Cases cannot be started until at least one ampule of every drug in the anesthesia machine is drawn ready for use. Endotracheal tubes, epidural sets, I.V. solutions are opened but may be unused. Some of these drugs and sets are quite expensive.

3. Professional communications are handled along large teaching hospital residency lines. This may result in enraged attending surgeons appearing in the anesthesia director's office or consuming his time in various committee meetings.

4. Intravenous lines, epidurals and intubations are often found to consume considerable time or the intervention of more senior colleagues. On occasion, simple cases are rendered complex. There may be a cascade of events which an individual lacking insight interprets as justifying his or her complex plan of management.

5. Present day graduates are notable for having a different and perhaps more enlightened approach to the workplace. Vacation, time off and breaks are given high priority. Complaints of overwork and fatigue may relate to greater sleep requirements in the young. At all events, it is my observation that when replacing a 60-year-old anesthesiologist, one will need two 30 year-olds.

Dr. Travis asks, 'Are these lessons from industry (aviation)?' As a Certified Flight Instructor with a special interest in aviation safety literature, I think I can respond. Notwithstanding the airline industry mandatory retirement of captains (which is the subject of intense debate), general aviation safety seems to improve with age. Pilots in their twenties have more accidents than those in their thirties, who in turn have more accidents than those in their forties, etc. I am wondering if a similar relationship may hold for anesthesia. The aviation analogy may not serve Dr. Travis, if he wishes to advocate for the young.

I hope the concerns raised by Dr. Travis and myself will both receive the a they deserve.

David L Atkinson, M.D. Director O Anesthesia

Cabrini Medical Center New York, NY

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Dryden Research Fund for Infection Study Set Up in APSF

Dr. Ellison C. Pierce, President of the Anesthesia Patient Safety Foundation, preceded the October 9 Board of Directors meeting with a special announcement: the creation of the "Gale E. Dryden, M.D. Research Fund." This fund is dedicated to support research on anesthesia-related nosocomial infections. Dr. Pierce stated, 'In this day and age, there can be little question that the prevalence of AIDS and the increasing incidence of our old nemesis, tuberculosis, highlights the importance of nosocomial infections as this relates to anesthesia practice.'

Gale Dryden has been a pioneer in this area of research with more than 40 publications on topics dealing with anesthesia equipment, and specifically concerning contamination and the risks of infection from anesthesia equipment. After obtaining his medical degree from the University of Cincinnati in 1947, and an internship at the Methodist Hospital of Indianapolis, Dr. Dryden pursued a period of general practice until 1955 when he entered a residency in anesthesiology at the Marion County General Hospital. He remained there in anesthesia practice and ultimately became Chairman of the Department as well as an assistant professor at Indiana University.

In addition to participating in the training of more than 800 residents, Dr. Dryden was awarded 19 patents for devices used in anesthesia practice. Among these devices were a disposable C02 absorber, a portable anesthesia machine, a nasal anesthesia mask, a disposable dear face mask, and many other devices. Well ahead of his time, Dr. Dryden developed a device for humidifying non-rebreathing systems in 1975. And at this time, Dr. Dryden has three additional patents pending.

Two of Dr. Gale Dryden's sons, Paul and Steven (a cardiovascular anesthesiologist) presented the check inaugurating the Dryden Fund to Dr. Pierce (see photo). Beginning in 1994, the Dryden Research Fund will award one grant for research in anesthesia-related nosocomial infections. Application forms may be requested from:

E.S. Siker, M.D., Executive Director Anesthesia Patient Safety Foundation

1400 Locust Street

Pittsburgh, PA 15219-5166

or by FAX (412-281-9485).

The deadline for applications is June 15,1994. The award will be announced at the annual meeting of APSF at the time of the ASA meeting in October.


Gale E. Dryden, M.D. 


CHECK PRESENTED: Steven Dryden, M.D. (Pr left) and his brother, Mr. Paul Dryden, sons of Gale E. Dryden, M.D. and representatives of the family and their fund raising efforts, present a check at the APSF annual meeting last October to establish the Dryden Research Fund within the APSF to APSF President E.C. Pierce, Jr., M.D. and (at the Pr right) E.S. Siker, M.D., APSF Executive Director. 


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ASA Exhibits Show Slight Safety Shift

by John H. Eichhorn, M.D.

Technical and scientific exhibits at the 1993 American Society of Anesthesiologists' Annual Meeting in Washington, D.C., October 9-13, had less emphasis on traditional monitoring equipment than in recent years and reflected some moderate development of newer aspects of patient safety.

Beyond the standard, expected displays of multiple possible mix-and-match configurations of what are now traditional electronic monitors for various physiologic and anesthetic parameters, airway equipment, devices, and techniques appeared to be the prominent type of display.

Easy Blind Intubation?

An extremely wide variety of laryngoscope types and styles as well as many different intubation aids were displayed and touted by manufacturers. All were expansions, extensions, or variations of described technology. One of the Scientific Exhibits, however, displayed a capnographically assisted stylette intended to facilitate blind intubation during spontaneous ventilation. Three separate gas sample aspiration channels (inferior, right, and left) are contained in a flexible, controllable stylette. Computer processing of the signal generates three waveforms on a display screen. When the three are concurrent, the tip of the stylette is pointed directly into the stream of exhaled gas and, presumably, towards the lumen of the trachea. When the three waveforms diverge, the tip of the stylette is not aligned with the stream of exhaled gas. The exhibitors claim that hand-eye coordination of manipulation of the stylette based on the display is easily learned and blind intubation of the trachea in patients with extremely difficult airways is greatly facilitated. The electronics are custom designed and could not be added to an existing capnograph. The project is still in development and no commercial product exists.

Various Tubes

Endotracheal tubes especially designed and manufactured to be used during laser laryngeal surgery were featured in seven commercial displays among the Technical Exhibits. Neural monitoring of one type or another was the submit of nine product displays. A product with an ECG electrode as part of an endotracheal tube (allowing another type of lead 'view' of the heart) was shown for the first tune.

All of these product displays and their attendant exhibitors mentioned the proposed safety advantages of their products to at least some degree.

A wide variety (at least ten) of 'information systems" were shown in the technical exhibits. Virtually all of the newer ones involve processing, recording, and display of data that involves manual input into a computer by the anesthesiologist before, during, and after an anesthetic. Refinements of existing brands and one new model of automated anesthesia records were also displayed, without any obvious major technologic breakthroughs in evidence.

IV Safety

One new product was an IV injection site monitor intended to detect subcutaneous extravasation of fluid and medications intended for intravenous infusion but not getting into the vein. This device is essentially a subcutaneous temperature monitor with a passive receiving device outside the body. In development are a display and alarm that would signal an errant IV injection/infusion and, eventually, the company envisions the same technology evolving into a new generation of temperature monitor measuring intrabody values accurately.

At least eight technical exhibits dealt with needle and injection safety. These, appropriately, were as much oriented to anesthesiologist safety (protection from accidental needle punctures) as to that of the patient. Holders, brackets, guides, covers, and ports were all involved in some way in the widely divergent family of devices displayed.

Safety of tourniquets used for vascular occlusion during extremity surgery was the subject of a Scientific Display that demonstrated the use of somatosensory evoked potentials to determine a safe occlusion pressure. Investigators noted that tourniquets are often inflated to extremely high pressures arbitrarily to guarantee no leakage of blood into a wound, but at the risk of ischemic damage, particularly to nerve tissue. Therefore, advocating the common theory that the lowest possible pressure would be the safest, the team used SSEP to verify that tourniquets could be set just a small pressure above occlusion pressure and preserve nerve integrity and minimize risk of complications while still providing a dry operative field.

Another Scientific Exhibit showed the endotracheal tube with the self-inflating bulb added to it that is constructed in such a manner that it demonstrates by its inflation characteristics whether the tube is in the trachea or esophagus. Multiple questions about its use were answered in the display. This device is in development and not now commercially available.

One Exhibit had an excellent display with models, including an artificial lung, illustrating appropriate procedures to follow in the 'can't intubate, can't ventilate' airway crisis. This work ties in closely with the ASA practice parameter on the difficult airway.

Several Exhibits involved computer-driven educational models and programs. Teaching tools for all levels of practitioners were seen, including interactive tutorial programs. Literature searching programs and data bases for various purposes were also featured.

In all, again this year, there were no profound breakthroughs equivalent to "the next pulse oximeter" displayed at the meeting . There were, however, several innovative and creative products and ideas shown that eventually may have incremental positive effects on anesthesia patient safety.

Dr. Eichhorn, Professor and Chairman of Anesthesiology at the University of Mississippi, is an APSF Director and Editor of the Newsletter.

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APSF Awards Research Grants for 1994

by Jeffrey B. Cooper, Ph.D.

Once again, the APSF Committee on Scientific Evaluation has selected projects for award of research grants. This year, three applications were selected from the 20 submitted by June 15. These three, as has been typical every year, represent a diverse spectrum of safety-related research.

As has been the policy over the past few years, feedback is given to principal investigators of applications that are not funded if such information is requested. Thus, the APSF Grants Program is intended not only to fund a few projects but also to play an advisory role with the objective of assisting investigators to design studies that will produce credible results and could possibly obtain funding from other sources.

The winners this year:

Drs. W. Bosseau Murray and A.J.L. Schneider

"A critical-events prompter for the anesthesia workstation."

Building on the trend toward inclusion of interactive monitor screens in anesthesia workstations, Dr. Murray and colleagues at the Department of Anesthesia, The Pennsylvania State University, College of Medicine, Milton S. Hershey Medical Center propose to design and test a 'critical events prompter' which would become part of the workstation.

In this two-year project, they will develop and clinically test multi-media programs based on the ACLS protocol to be used as interactive prompters to remind and assist in the management of intraoperative cardiac arrest. This effort is based on the general belief that rarely-used responses to critical events are remembered incompletely, applied incorrectly or not ever initiated. Prompting for correct responses is expected to improve performance.

W.B. Murray, M.D. 


T. Andrew Bowdle, M.D. 


Mark F. Newman, M.D. 

Coincidentally, and unrelated to the review of the proposal, this same group was presented with the APSF award for the best patient safety related scientific exhibit at the 1993 annual meeting. The exhibit included examples of multi-media presentations and a prototype of the interactive display that would be used in the study.

"Do benzodiazepines effect episodic desaturation during sleep in surgical outpatients?'

T. Andrew Bowdle, M.D.

This application explores an area that is a relatively new direction for anesthesia patient safety. Dr. Bowdle poses the hypothesis that exclusion of benzodiazepines from the anesthetic regiment will reduce the incidence of episodic hypoxemia during the first two postoperative nights in healthy surgical outpatients. Studies of breathing during sleep will be performed in the home of patients during one night of the week prior to surgery and during the first two postoperative nights. Interestingly, the observation that healthy patients undergoing minor, elective surgery are hypoxic for at least 24 hours following surgery was observed in 1962. Other studies since have corroborated this, although an association with mortality or morbidity has never been demonstrated. Still, Dr. Bowdle and his colleagues presented an effective argument for why postoperative episodic hypoxemia should be avoided if possible. Their emphasis on the possible role of benzodiazepines arises from previous studies suggesting that these drugs may cause or exacerbate sleep-disordered breathing. Dr. Bowdle and his co-investigators are at the Department of Anesthesiology, University of Washington in Seattle.

Dr. Mark Newman

"Does the technique of rewarming after cardiopulmonary bypass affect the extent of neuropsychological dysfunction?"

Dr. Newman and colleagues at the Duke Heart Center will examine a question that could affect the postoperative recovery of the substantial number of patients who undergo coronary artery bypass each year. They hypothesize that a precisely controlled, staged rewarming from hypothermic CPB will decrease the incidence of jugular venous desaturation, quantitative EEG signs of ischemia and, most importantly, the incidence and severity of neuropsychologic deficits after CPB. This idea derives in part from results of their previous studies in which it was determined that rewarming from hypothermic CPB is associated with a substantial degree of desaturation at the jugular bulb, implying an imbalance of cerebral oxygen apply and demand. Dr. Newman hopes that the knowledge generated from this investigation will have immediate applicability to cardiac surgery.

Dr. Cooper is an Associate Professor of Anaesthesia at Harvard Medical School and director of Biomedical Engineering, Massachusetts General Hospital. He is the chairman of the APSF Committee on Scientific Evaluation.

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New Standards Focus on Piped Medical Gas Systems
Part of a Series on "Out of Sight, Out of Mind: Behind the Wall"

by Thomas A. Nagle, M.B.A.

Historically, anesthesiologists' primary equipment concerns have been with the operation and reliability of their increasingly sophisticated anesthesia delivery system. Anesthesia systems usually undergo rigorous planned maintenance several times a year as well as daily user pre-operative checkouts. These are safeguards for patient safety and equipment reliability. There is, however, a critical equipment system used by anesthesia personnel which typically does not receive as much attention: the piped medical gas distribution system.

Without a doubt, piped medical gas systems are life support utilities which play key roles in the treatment of patients, especially during anesthesia delivery. Administration of pure, particulate-free gases at proper flows and pressures is vital for the proper operation of anesthesia system components (ventilators, vaporizers, pressure regulators, flow controls, etc.). A properly operating medical gas distribution system which meets or exceeds the various industry standards is important to the anesthesia practitioner.

For many institutions the medical gas system is viewed as 'out of sight, out of mind' until problems arise. In the current economic environment, funds are often focused toward revenue production, while operating costs are closely scrutinized. Together, these factors can result in very few resources being invested in the maintenance and testing of the piped gas systems.

Agencies that set the standards for the construction and operation of health care facilities have recognized the need for more attention directed toward piped medical gas systems. In 1993, the National Fire Protection Agency (NFPA) and the joint Commission on Accreditation of Healthcare Organizations UCAHO) adopted new requirements designed to ensure that medical gas systems are properly installed, maintained, and understood.

The NFPA makes very specific recommendations concerning the installation, maintenance, and testing of medical gas systems. When a medical gas pipeline is installed, renovated, or expanded, it must be certified to meet the current NFPA-99 Standard for Healthcare Facilities code adopted for that locale. This code is generally updated by the NFPA every three years, most recently in 1993. Older existing systems need not be updated to the current code unless there is a clearly hazardous condition in the existing system. The NFPA also makes very specific recommendations concerning the retesting of existing systems to ensure continued quality.

The NFPA is stressing these new standards because the certification and retesting of piped medical gas systems can prevent or eliminate problemts with system performance and can enhance user understanding.

The following are some common problems which may be avoided through piped gas system testing per NFPA recommendations:

* Improper plumbing/installation techniques.

* Improper use of construction materials.

* Improper location and filtration of medical air intakes.

* Presence of particulate matter.

* Inadequate pressure or flow

* Improper safety keying of gas outlets. s Leaking or broken gas outlets. , Cross connection of gases.

* Improperly connected or not functioning system alarms.

* Incorrectly located emergency shut-off.

* Improper labeling.

* Contaminants

(1) Dewpoint standing water in lines and

equipment (natural by-product from the manufacture of medical air which has not been sufficiently dried possibly due to undersized or faulty dryers).

(2) Presence of gaseous contaminants such as CO, C02, gaseous hydrocarbons (possibly entrained through air intakes from vehicle exhaust or introduced by faulty air compressors).

(3) Halogenated hydrocarbons (cleaning agents).

The need of testing for microorganisms is not outlined by the NFPA, but reports of gram negative bacteria are said to have been found in some systems.

New JCAHO Recommendations

Because of the importance of piped medical gas systems and their impact on patient safety and equipment performance, the JCAHO has also elevated the status of the piped gas system in the survey process. While the NFPA makes very specific technical recommendations, the JCAHO has more open ended requirements focused on maintenance of the piped gas system and the education of those who use it.

New 1993 survey standards adopted by the JCAHO require OR staff to be knowledgeable on various aspects of the system. They also place heightened focus on the hospital's responsibilities. "Where we've seen slippage (in medical gas performance), we've responded. The JCAHO (this year) has added new questions to the survey process to emphasize the need for improved maintenance and training," says Ode R. Keil, the JCAHO's director of plant, technology and safety management.,

The following are some excerpts taken from the JCAHO publication Plant, Technology & Safety Management Series (the 1993 KIPS hospital accreditation program [on] how to prepare for a PTSM survey) which draws specific attention to piped medical gas systems:

PL.4.3. A current, accurate, unique inventory is kept of all equipment for utility systems included in the program. It is further stated that, '...the inventory for piped medical gas systems must include alarms, valves, automatic pressure switches, flexible connectors, and outlets.'

PL.4.4. Utility systems operational plans are written to help assure reliability, control risks, reduce fatigue, and train users and operators of the systems.

PL.4.4.1. The hospital develops procedures and establishes intervals for the testing and maintenance of equipment for utility systems included in the program. It is further stated that, '...written procedures for testing and maintaining piped medical gas systems must include cross-connection, contamination, and pressure testing when the system is installed, modified, or repaired." It is further stated that, '...established intervals for testing and maintaining piped medical gas systems must include alarms, valves, automatic pressure switches, flexible connectors, and outlets.'

PL.4.4.3. Orientation and education is provided in accordance with SE.1 through SE.4.4. for individuals who use and/or maintain utility systems are documented.

PL.4.5. There is a current, complete set of documents that indicate the distribution of each utility system, including controls for a partial or complete shutdown. It is further stated that, '...must include piped medical gas system.'

PL.4.5.1. Where provided, emergency shutoff controls are labeled. It is further stated that, ' and area shutoff valves for piped medical gas system must be accessible and clearly identified.' It is stated that, '...random sample of personnel who use or maintain the piped medical gas system must be able to describe the location and function of normal and emergency controls for the system.'

Hospital staff should be especially aware of PL.4.5.1. which permits surveyors to randomly approach staff members and question them on the location and function of the system's alarms, shutoff valves, and so on.

Respiratory therapy departments also have a role in managing piped medical gas systems. This role is particularly important to clinicians who have patients supported by the respiratory therapy department and to those medical directors who oversee this department. As outlined in the 'Intent' section of RP.3.3 of JCAHO Accreditation Manual for Hospitals, 1993: 'The respiratory care department/service should have a mechanism for managing respiratory equipment and medical gas systems so that therapeutic gases are administered safely. This requires developing and implementing policies and procedures for testing, maintaining, and operating the system and for verifying the integrity of the equipment and the system.'

The responsibility to comply with most of He above maintenance issues usually rests with the institution's plant engineering department. However, the extent to which institutions adhere to industry recommendations concerning piped gas systems can have an impact on patients, clinicians, and equipment.


Piped medical gas systems network through multiple clinical areas of most hospitals. New standards have been implemented to encourage the support of these systems which have traditionally been 'out of sight, out of mind." As a primary user group, the anesthesia staff should play a key role in communicating the need to guarantee that this fife support utility system is properly understood and maintained.

Thomas A. Nagle, M.B.A., is the service marketing manager for Ohmeda, Madison, M. Ohmeda manufactures and provides field testing services for piped medical gas delivery systems.


1. Weisman Ellen, NFPA and JCAHO Look at Medical Gas Systems, Health Facilities Management Vol. 5, No. 8 (August 1992):28.

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MHAUS Acts to Keep Hyperthermia Patients Safe

by Henry Rosenberg, M.D.

Malignant hyperthermia (MH) in the past has been a greatly feared anesthesia complication and a significant threat to the safety of a small but definite number of patients. Presented here is information about why this threat is much less today and also some background information about what is happening with MH.

The Malignant Hyperthemia Association of the United States (MHAUS) was founded in 1981 to provide information, education and assistance to health care providers and patients who have a special interest and concern with this inherited disorder.

MHAUS produces a newsletter (The Communicator) five times/year, brochures dealing with various aspects of MH, treatment guidelines, as well as periodic conferences for professionals and lay persons. An important aspect of the activities of MHAUS is a hotline service available with the cooperation of The Medic-Alert Foundation 24 hours a day (telephone (209) 634-4917).

Callers dealing with MH questions of an urgent nature may contact an MH expert and request advice and assistance. Each year, approximately 600 calls are handled by hotline consultants.

A representative sample of recent calls received by the hotline and summarized by Dr. Rory S. Jaffe, Assistant Professor of Anesthesiology at the University of California, Davis, is presented below. For further information about MHAUS, call (203) 8470407, or write to MHAUS, P.O. Box 191, Westport CT 06881-0191.

MHAUS received 152 Hotline reports in the Spring of 1993. Sixteen consultants from the United States and Canada submitted reports. Fifty-six calls were consultations for patient management: 14 episodes of postoperative fever, two cases of neuroleptic malignant syndrome, and 40 perioperative events of which 14 were masseter muscle rigidity. Two deaths, which will be discussed below, were reported.

The most remarkable call for help came from the friend of a parent of a child having femur and wrist fractures repaired. There was a language barrier; he called from Mexico City, and spoke little English. it appeared that the child may have had an MH reaction, and they were attempting to obtain dantrolene. The consultant suggested trying a teaching hospital or major medical center in Mexico City. The hotline consultant could not assess the need for dantrolene, asked for the patient's doctor to call (with an interpreter), and contacted Proctor and Gamble about the availability of dantrolene in Mexico. No doctor ever called. A representative for Proctor and Gamble said that they do not sell dantrolene in Mexico. It can be obtained through an intermediary, which takes about one week. Nothing more was known until three days later, when the father called. They had unsuccessfully searched for dantrolene in Mexico City, and the little girl had died.

In some parts of the world, people have access to diagnosis of MH susceptibility and specific treatment of acute episodes. Prior to dantrolene, MH truly was malignant, with a death rate exceeding 70%. Without dantrolene, most patients died even with ideal supportive care. In the past, United States physicians have received calls for information from Mexico, and most did not realize that Mexican doctors and hospitals do not have ready access to dantrolene. In a country with limited resources, how many deaths should be tolerated to save money? In Mexico City, with about 21,000,000 residents, 1:10,000 to 1:40,000 MH susceptible, 500 to 2,100 people are at risk for triggering. Can they afford to stock dantrolene to help save those people? Should Proctor and Gamble donate a supply? There is no ready answer, but this girl would probably still be alive if she had her operation in another country.

Not Always MH

The other death was also quite unusual, although no one could have prevented the outcome. A 35-year-old woman with a tibial plateau fracture was given a general anesthetic including succinylcholine to relax her muscles for intubation and isoflurane for anesthesia. After tracheal intubation, she developed hypotension and tachycardia. Ventilation became difficult, and her temperature rose. She then suffered a cardiac an-est. The consultant was called during the resuscitation attempt. The serum potassium level was normal, and the blood gases were not appropriate for severe MH. The consultant felt that MH was unlikely, but a small dose of dantrolene was given. The patient died, and the autopsy revealed a massive pulmonary embolus. Fever and tachycardia are common with pulmonary thromboembolism, and induction does seem a time of increased risk for pulmonary embolism. Perhaps the increased risk is due to stirring up pelvic vein clot in an immobile patient with movement to the operating room table or muscle fasciculations with succinylcholine.

Fever either postop or not associated with an operation resulted in 14 calls to the hotline. None were thought to be MH although the consultant recommended measuring blood gases every 30 minutes in one patient. Several were thought to be drug fevers: one from radiologic contrast, and one from cefazolin.

Masseter Spasm

Masseter muscle rigidity was the cause of 14 calls to the hotline. Three of these patients received dantrolene, and one was felt to have experienced an MH episode. AU patients were referred for biopsy to exclude MHS. The consultants all recommended hydration and precautions against renal damage from myoglobinuria. AU patients recovered rapidly.

Of the other 28 consultations for acute management, six were considered acute MH, 12 possible MH, and six unlikely to be MH. These patients did well. Two calls were to request assistance for the management of neuroleptic malignant syndrome (EMS) and two were for myoglobinuria. Both patients with myoglobinuria were referred to a neurologist for evaluation of myopathy. Neither of the patients with NMS required dantrolene.

Ninety-seven calls were information requests. Besides general management questions, the most prevalent question asked was for an assessment of risk for a relative of someone either MHS or suspected to be MHS (19). Close behind was the frequently asked question 'Are all local anesthetics O.K.?' (13) One questioner was curious about using Edocaine for MH-induced arrhythmias, The consultant said it was fine. MHAUS literature still recommends procainamide for treatment of arrhythmias. This may cause some of the concerns regarding amide-local anesthetic use and may need reevaluation. The suitability of other drugs was also the subject of inquiries: propofol (4), mivacurium (2), hydroxyzine, potassium, vecuronium, chloral hydrate, cortisone, and OTC medications.

A request for post hoc evaluation of a recent case was the reason for 10 calls. Most were episodes of trismus. One patient had been discharged immediately postop and was recalled to the hospital after the consultation. Many of these patients were referred for biopsy.

One patient referred for biopsy had 12-14 uneventful general anesthetics, including one known to include succinylcholine and isoflurane, without trismus. She recently had two anesthetics and was difficult to intubate after succinylcholine both times. This was perhaps due to trismus, but cannot be definitely confirmed. After that last anesthetic, she had very severe myalgias. The peak CK was 920. Her physicians were questioning whether this represented MHS or a difficult airway. Her biopsy was strongly positive, including contractures of 6.38, 2.32, and 3.06g to 3% halothane.

Four calls to the hotline were regarding the duration of postop observations for MHS patients given nontriggering anesthetics. Twice callers were told no additional observation was needed, and twice consultants said that about six hours were needed. This represents an area where there is still little solid ground to base any recommendations upon. No MHS patient given a non-triggering anesthetic has ever been known to develop MH because of that anesthetic. Late development after operation is felt by many to be quite rare. But what if this MHS person was inadvertently exposed during anesthesia to a volatile anesthetic? How long is long enough to exclude accidental triggering?

Various syndromes were asked about: myotonic dystrophy (2), arthrogryposis, osteogenesis imperfecta, Freeman-Sheldon syndrome, Russell-Silver syndrome, McArdles syndrome and Sp+ syndrome. Reflecting current controversy, one caller was advised that myotonic dystrophy is probably associated with MH, and one was told it is not. Other questions were regarding tourniquet use in the MHS patient, dantrolene pretreatment (seven calls, all told "no'), and military acceptance of MHS applicants.

Nugget Mining

Two callers were preparing lectures; one requested urgent FAX transmission of all MHAUS literature for the lecture (It is assumed her donation to MHAUS is forthcoming). One caller was studying for the oral boards and mining the consultant for nuggets of information useful for the exam.

The MH experts who volunteered their time and talents in assisting these callers were Drs. Allen, Bikhazi, Chapin, Greenberg, Jaffe, Kaplan, Karan, Larach, Miller, Muldoon, Rosenbaum, Rosenberg, Sessier, Shutack, Watson and Wedel. MHAUS thanks them for their generous donation of time and expertise.

Dr. Rosenberg is Professor and Chairman of Anesthesiology at Hahnemann university, Philedelphia, and also the Vice President for Medical Affairs and Chairman of the Professional Advisory Council of MHAUS,

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In My Opinion: A Debate

Jeffrey S. Vender, M.D., Column Editor Reader Response Invited

Should Epidurals be Used in Patients Who Get Systemic Anticoagulation?

'Yes: Regional Anesthesia and Anticoagulants are OK'

by John P. Williams, M.D., and Sture G. Blomberg, M.D., Ph.D.

The use of any technique in anesthesiology is accompanied by some quantifiable risk to the three P's: public, patient and practitioner. In order to rationally assess the relevance of the type of risk imposed by a technique, one must first decide which of these groups is at risk, what specific risk is imposed (i.e., what is the incidence of the selected outcome), what possible benefit(s) is/are derived and finally what risks/benefits are posed by alternative techniques. Unfortunately, time and space constrain this debate only to considerations of practicality.

From all these perspectives, the greatest risk is neuraxial hematoma formation. However, the issue is not whether administration of neuraxial anesthetics in the presence of anticoagulation poses significant risk. More properly stated it is: does the combination (of neuraxial anesthetics and anticoagulation) increase the risk of neuraxial hematoma above that of either alone and if so is that increase additive, geometric or exponential?

Several studies have documented the safety of neuraxial anesthetics: Dripps' (approximately 10,000 neuraxial anesthetics), a similar Chinese study (10,000 neuraxial anesthetics), Lund's review of 150,000 neuraxial anesthetics, Kane in his landmark study of the incidence of neurological injury following spinal and epidural anesthesia noting a 1:45,783 incidence of paraplegia directly attributable to the anesthetic. Presumably, a few of these anesthetics were administered in the presence of anticoagulation (either pharmacological or pathological); if so, one would expect to find a noticeable increase in neurological injury if the additional burden of anticoagulation exponentially or geometrically increased the risk of neuraxial hematoma. Thus if an increased risk exists, it is only additive.

More direct evidence is available from the work of Rao and El Etr who noted no increase in the risk of neurological impairment when administering epidural anesthesia prior to system heparinization for vascular surgery (approximately 4,000 neuraxial anesthetics). A corroborative report by Odoom and Sih supports Ns finding (approximately 1,000 neuraxial anesthetics). Although Yeager did not intend to examine the role of neuraxial anesthetics with regard to the incidence of neuraxial hematoma, he did not detect an increase.

More recently, Blomberg (1) and Liem (2) examined the role of neuraxial anesthetics in ischemic heart disease: the former in the setting of unstable angina, the latter for coronary artery surgery. Neither investigator noted an increase in the incidence of neurological impairment. Dr. Blomberg's epidurals were inserted after discontinuing heparin for four to six hours. Dr. Liem's patients underwent instrumentation on the evening prior to surgery. Both of these represent traditionally 'high-risk' patient groups for neuraxial instrumentation; yet, neither investigator noted any evidence of neuraxial hematoma formation.

The benefits of neuraxial regional anesthesia during coronary artery bypass surgery include: more thorough rewarming following cardiopulmonary bypass, more rapid extubation, shorter stays in ICU, superior analgesia, decreased incidence of postoperative ischemia, improved patient communicative skills, and shorter awakening times.

The benefits of thoracic epidural anesthesia in unstable angina include: decreased utilization of intravenous heparin and nitroglycerin, increased exercise tolerance on treadmill tests, decrease in the number and duration of anginal episodes, an increase in the global ejection fraction, and an increase in the resting diameter of stenosed coronary arteries. Perhaps most impressively, these epidurals were inserted in patients who were refractory to conventional medical therapy (intravenous nitroglycerin and heparin). While this was not a prospective randomized study, it is tempting to speculate that some of these patients did not proceed to infarction principally because of this regional sympathetic blockade.

The benefits of neuraxial anesthetics as noted by Yeager' and his group were: shorter ICU stays (although after log-transformation of the original data the difference was not significant), decreased morbidity from several causes (CHF, pulmonary, sepsis), shorter hospital stays (similar comment as regards ICU stays), and decreased hospital charges. Indeed, the Yeager group terminated their trial early because of the dramatic difference in morbidity between the general and regional anesthetic groups.

What benefits does general anesthesia provide? In head to head comparisons with regional neuraxial anesthesia techniques none. Is the risk of neuraxial hematoma formation absent with general anesthesia? No. A recent paper in the Japanese literature reports the occurrence of an epidural hematoma following cardiopulmonary bypass in the absence of any manipulation or instrumentation of the neuraxis (i.e., a spontaneous epidural hematoma).

Where does this leave us? Clearly the public has much to gain from the use of neuraxial techniques. Improved pain relief, the rapid ability to communicate with practitioners and family members, and a decrease in the incidence and severity of myocardial ischemic and other co-morbid events. In return, they (and we) assume a risk of neuraxial hematoma. Is this risk made greater by the addition of neuraxial instrumentation? We do not know this as yet. Only large-scale prospective comparisons or retrospective meta-analyses will give us that answer.

It is interesting to look back on the history of endotracheal intubation for comparison. The incidence of unrecognized esophageal intubation was and continues to be a risk to the use of endotracheal anesthesia (currently approximated at 1:100,000). However, this low incidence is at least partly a result of years and years of dedicated research into less expensive (read easily available), more reliable methods of detecting this complication; not by recognizing that endotracheal intubation was a problem and ending the discussion. As an old adage states, "Never were my eyes so open as when I first began to see.' Let's open our eyes and search for new methods of detection; not shut them and complain about the light!

Drs. Williams and Blomberg are on the faculty of the Department of Anesthesiology, UCLA School of Medicine, Los Angeles, CA.


1. Blomberg S, Emanuelsson H, Kvist H, Lamm C, Ponten J, Waagstein F, Ricksten S-E. Thoracic epidural anesthesia and central hemodynamics in patients with unstable angina pectoris. Anesth Analg, 69:558-562,1989.

2. Liem TH, Booij LH, Hasenbros MA, Gielen MJ. Coronary artery bypass grafting using two different anesthetic techniques: Parts 1-3j. Cardiothorac Vasc Anesth 6:148-167,1992.

3. Yeager MP, Glass DD, Neff RK, Brinck-Johansen T. Epidural anesthesia and analgesia in high-risk surgical patients. Anesthesiology 66:729-736,1987.

'No: A Case Against Thoracic Epidurals in Systemically Anticoagulated Patients'

by John Tinker, M.D.

The case I wish to make against this practice involves risk versus benefit. I am sure that my worthy opponents in this 'debate' will carefully delineate all the real and/or potential benefits to be achieved by this practice, e.g., better analgesia, which is above all more humane but which may also have the not-so-side-benefits of better pulmonary toilet, shorter intensive care and then hospital stay, etc. The problem here is not with the benefits, which I'm sure in good hands are substantial, but with the risk.

When we think of risk benefit ratios, we tend to think of risk in terms of incidence, rather than rnagnitude, of complications, because incidence is much easier to quantify and contemplate. Actually, for most uncommon or rare complications, it is the magnitude about which we probably should be concerned. A thoracic hematoma leading to an infection and/or paraplegia is possible with this form of therapeutic intervention. It is not likely. It is not even remotely likely. It is probably not even quantifiably likely, at least not reliably so. Lawyers have argued that such rare complications are so unlikely that, if they occur, there must have been some sort of negligence (a questionable premise, but one which has carried the day in several cases).

Although I think the above lawyers' argument is specious, there probably is validity in the contention that if a devastating complication is very rare in a general population, and if the treatment associated (rarely) with this complication is a complex treatment requiring superior mechanical skills (and this is the case for thoracic epidurals), then that rare and/or devastating complication might be expected to be more likely if the skill level of the practitioner was not of the highest degree or, perhaps, a reasonably skilled practitioner was having an "off day.' Before you make fun of my "off day,' think of any professional athlete of your choice. The greatest baseball players have slumps at the plate. Sometimes a golden glove outfielder will make two or three sophomoric blunders in the same game. How many times have you had two or three failed attempts at arterial cannulation in a row? I do believe there is validity to my contention that if a therapeutic intervention requires first class mechanical skills, then complications arising therefrom can be reasonably expected to occur with greater frequency if the practitioner either has less experience, or a lower mechanical skill level, or an 'off day.'

Devastating Complications

Whether the above is valid or not, the fact that these devastating complications can occur is crucial to my argument that the magnitude as well as the incidence of complications must affect the 'acceptability' of any resultant risk benefit ratio. For this particular procedure (and all others), there is a real risk benefit ratio. That ratio is almost never known and may change over time for a given procedure, when done by a given practitioner, or because of many factors, but there is such a ratio, always present at any particular time.

With any rare and devastating complication, therefore, the practitioner will have trouble with a question something Re 'how many of these rare but devastating complications am I willing to tolerate in order to gain real but not necessarily life-saving benefit in most of my patients so treated?'

Some will opine that I am posing no particularly difficult ethical question, since we make such decisions all the time. Deciding to cross the street or get on an airline entails risk of getting killed by a bus, or a crash, yet we often take these risks for decidedly 'elective' reasons. The difference, I would point out, is that we are exposing ourselves to these well-known risks. Even if we kid ourselves that the incidence is lower than it really is, we are, as lay people, able easily to understand the magnitude. Deciding to perform a thoracic epidural for pain relief, doing it on a stranger who is unlikely to understand the magnitude of a hematoma or infection or even paralysis (do you really even use the dreaded word, in your 'informed' consent? I'll bet you usually don't!), is to decide for someone else to take the risk an entirely different proposition.

Let me take a different example. If performance of deliberate hypotension during scoliosis repair operations in young patients saves blood (and that is controversial, but it probably does), and if there are rare complications from said hypotension, e.g., unilateral blindness, paraplegia, etc.), then how many paraplegic young patients are you willing to accept (per thousand or per million) in order to save two or so units of blood per patient? In this particular example, 15 years ago the 'saving' of two units of blood might well have been considered far less important than similar savings of blood would be today, based on the AID's virus, far greater expense, non A-non B hepatitis, etc. Today, it might be easier to justify performance of deliberate hypotension for scoliosis repair than it was 15 years ago.

What about thoracic epidurals for postoperative analgesia in patients who have been Oven anticoagulants in the course of their surgery, albeit after the placement of the epidural catheter? How many thoracic epidural hematomas per thousand patients so treated are you willing to accept? How many epidural space infections? How many paraplegias? Because the risk of these complications is so small, it is unlikely to ever be possible to actually calculate a risk benefit ratio. Such a risk benefit ratio might be meaningless anyway if the complication is dependent to a considerable extent upon individual practitioner skill level.

Perhaps a better test is to ask yourself what you would like to hear from your anesthesiologist about this procedure? Would you want your anesthesiologist to tell you that there is a rare but non zero likelihood of paraplegia, or a year in pain, bed rest with an epidural space infection? Do you tell that to your patients prior to performance of this procedure? Perhaps this is the right ethical 'test.' If you do tell your patients something like the above in all candor and frankness, and if you then can state with equal candor that despite this very remote possibility, you strongly believe that the pain relief afforded by the procedure is worth this small risk of this devastating complication, then it seems to me that you have properly come to grips with the ethics of this problem. If, on the other hand, you are telling your patients that the risk is 'small' and you are deemphasizing the magnitude of the complication, however rare, then you should rethink not only your process of informed consent but your internal rationale for performance of the procedure in the first place. Many anesthesiologists say something glib at this critical juncture in the informed consent process, like "the risk is smaller than getting struck by lightning.' I have heard this nonsense stated frequently. The reason is because the denominator is not the same! In the risk of being struck by lightning, the denominator is the U.S. population, compared to a denominator which must include only the (U.S.) population of patients having thoracic epidurals for surgery in which anticoagulants were used!

Pain control can be achieved other ways. I remain unconvinced that the epidural route of administration of narcotics has conclusively been shown to be more effective than opioids administered intravenously in a 'patient controlled" fashion, if proper dosages are given. Because I believe this, I have difficulty telling patients that the "benefit' of this is so great that the risk of a devastating complication can be justified.

There is always in medicine a tendency toward anecdotism, as opposed to scientific comparisons. Many colleagues of mine have read the various studies comparing, for example, epidural analgesia with intravenous PCA, and have stated that they intend to continue the epidural route because, despite the studies, they 'know' their method is better. They say things like 'all you have to do is go out and see the patients.'

Thomas Preston, in his 1977 book Cardiac Surgery A Critical Review (Raven Press, NY), stated: 'The history of medical therapeutics shows that most medical treatments do not stand the test of time, especially those that are controversial within their own times." This particular therapy, when used with anticoagulated patients, will Rely, I predict, fit Preston's wise characterization, especially if payors (reading the studies, not listening to the anecdotes) won't pay for it.

Dr. Tinker is Professor and Chairman, Department Anesthesiology, University of Iowa

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AWARD WINNER: The 1993 APSF Award for the best ASA Scientific Exhibit related to patient safety went to a group from Penn State University College of Medicine for a exhibit titled "Interactive Multimedia Displays in Anesthesia.' Pictured here are Kirk Shelley, M.D. (right), first author, and co-author Mr. Steve Mentzer. Additional co-authors were Art Schneider, M.D. and Mr. Michael Halm. Two computer programs were displayed: a departmental index and directory and an information workstation designed to assist in management of anesthesia complications.

The Anesthesia Patient Safety Foundation Newsletter is the official publication of the nonprofit Anesthesia Patient Safety Foundation and is published quarterly at Overland Park, Kansas. Annual membership: Individual $25.00, Corporate $500.00. This and any additional contributions to the Foundation are tax deductible. @Copyright, Anesthesia Patient Safety Foundation, 1993

The opinions expressed in this newsletter are not necessary those of the Anesthesia Patient Safety Foundation or its members or board of directors. Validity of opinions presented, drug dosages, accuracy and completeness of content are not guaranteed by the APSF.

APSF Executive Committee:

Ellison C. Pierce Jr., M.D., President; Burton A. Dole, Jr., Vice-President; David M. Gaba, M.D., Secretary; Casey D. Blitt, M.D., Treasurer; E.S Siker, M.D.; Executive Director; Robert C. Black; Robert A. Caplan, M.D.; Jeffrey B. Cooper, Ph.D.; Joachim S. Gravenstein, M.D.; W. Dekle Rountree, Jr.

Newsletter Editorial Board:

John H. Eichhom, M.D., Editor; David E. Lees, M.D. and Gerald L. Zeitlin, M.D., Associate Editors; Stanley 1. Aukburg, M.D. Jan Ehrenwerth, M.D., Nancy Gondringer, C.R.N.A.; Jeffrey S. Vender, M. D., Ralph A. Epstein, M.D., Mr. Mark D. Wood.

Editorial Assistant Nola Gibson, Ph.D.

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Address Newsletter editorial comments, questions, letters, and suggestions to:

John H. Eichhom, M.D.

Editor, APSF Newsletter

Department of Anesthesiology

University of Mississippi Medical Center

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