APSF-Sponsored Research Reveals that
Capnograph Supplements Oximeter
Swiss, German Care Guided by Monitoring Recommendations
Letters to the Editor
ASA Committee on Peer Review
Society for Technology in Anesthesia Slates Meetings Around the World, Calls for Abstracts for January Conclave in Florida
From the Literature: Has Anesthesia Mortality Been Decreased?
Equipment Industry Targets Increased Anesthesia Safety
Recommendations for the Monitoring of Patients During Anaesthesia (France)
French Publish New Monitoring Guides
BP Changes Tied to Complications
by Charles J. Cote, M. D.
A prospective evaluation of pulse oximetry and capnography in the care of anesthetized pediatric patients was undertaken in 1989 by the Pediatric Anesthesia Group at the Massachusetts General Hospital. This work was made possible by a grant from the Anesthesia Patient Safety Foundation combined with funding and equipment grants from Nellcor, Inc., Hayward, CA.
In a previous study at this institution, we found a significant reduction in the incidence of hypoxic events in children whose anesthesiologists had pulse oximetry data available to them and, compared to the entire pediatric population, and increased incidence of events in high risk patients (physical status III and IV) and in children less than two years of age. The Current study was designed to determine if capnography contributed to improved care of pediatric patients.
Following approval of the Subcommittee on Human Studies as well as Written informed consent, patients of physical status I through IV scheduled for surgical procedures under general anesthesia were studied in a randomized single-blinded prospective fashion. Patients were randomly assigned to one of four groups, A: pulse oximetry and capnography data available to those administering the anesthetic; B: only pulse oximetry data available; C. only capnography data available; and D: neither pulse oximetry nor capnography data available to the anesthesia team.
An additional anesthesiologist (whose only task was to record data) secured demographic information as well as a continuous strip chart recording of oxygen saturation, expired CO2, electrocardiogram, and the plethysmographic output from the oximeter. The observing anesthesiologist interviewed the anesthesia team and recorded events whenever a problem occurred. A major hypoxic event was defined as a decrease in the oxygen saturation to < 85% for >30 seconds and hypo- or hypercarbia were defined as an expired C02 < 25 mmHg or > 55mmHgfor >60seconds.Ifoneoftheseconditions arose during blinded data recording, the observing anesthesiologists informed the anesthesia team that a problem was Liking place and then later interviewed them. Whether or not the monitor data were available, the subject anesthesiologist doing the case was questioned as to awareness of the occurence of any problem.
35 % Have Problem
During the course of this study, 402 pediatric cases were examined and 232 problems were observed in 142 patients. There were 59 major hypoxic events in 43 patients and 73 problems related to ventilation in 58 patients. The number of patients with hypoxic events was significantly greater in groups C and D, i. e., no oximeter available, compared to groups A and M i. e., oximeter available. Patients less than two years of age and those managed with endotracheal intubation, had a higher incidence of these major hypoxic events. The pulse oximeter allowed diagnosis of 4 1 events; the diagnosis was made clinically in 13, and by the capnograph in five. Interestingly, four out of five hypoxic events diagnosed initially by capnography, were diagnosed by the observer rather than the anesthesiologist conducting the anesthetic. The capnograph was first to reveal and detect 88%of the 73 problems related to ventilation. Fifty-one of these were hypercarbia, seven hypocarbia, eight esophageal intubations, (three of which were first diagnosed by the capnograph), three circuit disconnects and four endotracheal tube obstructions. Only five of these 73 problems related to ventilation resulted in major episodes of desaturations.
This study clearly demonstrates the efficacy of pulse oximetry in detecting and preventing intraoperative hypoxemic-events in children. The incidence of hypoxemic events in this study was nearly identical to our previous study of pulse oximetry and the patient population at greatest risk was once again children less than two years of age. The capnograph did not appear to make a sufficient contribution to reducing events which lead to hypoxemia since all events leading to hypoxemia were either diagnosed first by the pulse oximeter or by the capnograph only when they were observed by a UIH party and not by the primary anesthesiologist. On the other hand, the capnography appears to make significant contribution toward the care of pediatric patients by detecting problem related to ventilation that do not necessarily lead to hypoxemia, such as hypercarbia and hypocarbia. Pulse oximetry is a more specific monitor for safeguarding against clinically important events leading to hypoxemia during pediatric anesthesia.
Other interesting observations related to " study included a poor relationship to ventricular arrhythmias to hypercarbia, a rather frequent incidence on intra-operative endobronchial intubation diagnosed by minor but persistent changes in oxygen saturation, and a very high incidence of false alarms. False alarms of the capnography resulted in the anesthesiologist frequently ignoring the capnograph alarm. Additionally, an increased incidence of minor but not major hypoxemic events was observed in children with symptoms of a mild upper respiratory infection compared to those without symptoms. The latter observation is consistent with those of previous investigators.
The exact importance of these other observations awaits more detailed analysis of the data. Nevertheless, this study clearly suggests that pulse oximetry is the most important monitor in helping to prevent events which lead to severe "n desaturation whereas capnography is important in preventing untoward episodes related to ventilation, including those not necessarily leading to hypoxemia.
Dr. Cote is Associate Anesthetist, Massachusetts General Hospital; Associate Professor of Anesthesia, Harvard Medical School, and Norbert Rolf, M. D., Research Fellow, Massachusetts General Hospital.
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by Professor Thomas Pasch
Anesthesia practice regulations, some of which have been in existence for quite a long time, help guide anesthesia care in Switzerland and the Federal Republic of Germany.
By way of background, note that in 1978, the Health Council of the Netherlands submitted to the Minister and the State Secretary for Health and Environmental Protection an Advisory Report on Anesthesiology, which was published in 1980. This report contained regulations covering the provision of anesthesiological workplaces with monitoring equipment @ In October 1986, the ASA issued their Standards for Basic intra-operative Monitoring! Following this, the national societies or associations of Canada (1987), Australia (1988), Singapore (I 988), United Kingdom and Ireland (I 988), Belgium (1989) and France (1989) adopted and issued 1,2,1 recommendations for Monitoring during anesthesia.
In August 1986, a Committee of the Swiss Society of Anesthesiology and Reanimation adopted Guidelines for Monitoring in Anesthesia. These stipulate that the equipment required for minimal monitoring must be considered a standard provision for the conduction of an anesthetic, and must consist of:
a) ECG monitoring.
b) Disconnected alarm that gives an audible signal.
c) An 02 monitor with a lower limit alarm (inspiratory 02 concentration measurement or pulse -oximetry).
d) Equipment for the monitoring of temperature and muscle relaxation (peripheral nerve stimulator) must be available
e) For cardiopulmonary resuscitation, appropriate equipment, including a defibrillator, must be made available within an acceptable tune
f) In every hospital, facilities for the following examinations must be available on a 24-hour basis: ECG, chest X-ray, blood gas analysis,
hemoglobin/hematocrit, potassium, creatinine, blood sugar, coagulation.
g) The following devices are identified as useful and desirable for anesthesia: C02 monitor, automatic sphygmomanometer, pulse oximeter, blood-warming machine.
Equivalent to the standards recommended by the ANSI, a Swiss Standard (SN 057 600) has been available since 1987 entitled Inhalation Anesthesia Systems Employing Continuous Flow for Use in Human Medicine. An 02 analyzer must be incorporated within the anesthesia system. This device should he provided with an adjustable low concentration limit alarm that gives both an optical and acoustic signal. A pressure gauge in the breathing circuit is recommended.
Since June 1984, the German Standard (DIN 13253) Inhalation Anesthesia Machines Technical Safety Requirements and Testing has been available in the Federal Republic of Germany. Virtually identical with this is the Standard OENORM K 2003 issued in Austria in June 1988. The following monitoring devices are required:
a) An 02 concentration measuring device incorporated within the inspiratory limb of the breathing system provided -with an adjustable low concentration limit alarm that gives an audible signal.
b) Pressure gauge in the breathing system.
c) For automatic ventilators, a disconnect and a stenosis (excessive pressure) alarm.
d) A spirometer in the expiratory limb if a circle system is employed
e) If the ventilation pressure and volume cannot be measured owing to the mode of function of the anesthetic equipment, alternative procedures must be employed, for example, end-expiratory C02 monitoring.
Agent Monitoring Required
In January 1985, the government of the Federal Republic of Germany issued a Decree on the Safety of Medical-technical Equipment (MedGV). In this, it is required that the devices involving the dosed application of energy or medications must be provided with an alarm facility that is activated in the event of a device related dosaging error. Since inhalation anesthetic machines fall within this regulation, from January 1, 1988, they must be provided with a facility for measuring the amount of a volatile anesthetic delivered by the vaporizer.
In October 1989, the German Society of Anesthesiology and Intensive Care Medicine, together with the Professional Association of German Anesthetists issued their Guidelines for Quality Assurance in Anesthesiology. (6) These make a differentiation between the organizational requirements (process quality) and spatial, equipment, and staff requirements(structure quality)of quality assurance. As in the case of the guidelines employed in the Netherlands, any attempt to stipulate what devices must be employed for given operations or anesthetic techniques was deliberately avoided. What is stipulated, however, is what devices have to be available for the specific task in hand. Whether and when such devices are employed is left to the decision of the anesthesiologist, who is required to proceed in accordance with the requirements and circumstances of the individual case.
The table lists the equipment applicable to the area of general surgery. In the case of a non-operative workplace(for example diagnostic, obstetric), CVP measurement, three-channel recording of the ECG, relaxometry and invasive arterial pressure measurement can all be left out. This also applies to the area of outpatient anesthesia, for which C02 monitoring, too, is not mandatory. For workplaces in the field of pediatric surgery, chest surgery and surgery on the major arteries, cardiac surgery and neurosurgery, additional requirements are needed, which, for reasons of space, cannot be listed here. However, copies of all the guidelines and recommendations mentioned in this paper can be requested from the author.
Thomas Pasch, M. D., is Professor Anesthesiology and Chairman of the Institute of Anesthesiology at the University Hospital, Zurich, Switzerland.
1. Adams AP. Recommendations for monitoring standards in the U.K. and Ireland. APSF Newsletter 1989; 4:32-3. 2. Belgium standards for patient safety in anaesthesia. Acta Anaesthesiol US 1989; 40; in press.
3. Crul T. The Netherlands national approach to standards of safety and care in anesthesia. Eur J Anesthesiol 1987; 4:213-5.
4. Eichhorn, [H. ASA adopts basic monitoring standards. APSF Newsletter 1987; 2:1-3.
5. Faculty of Anesthetists, R.A.C.S. Statement June 1988. Monitoring during anaesthesia (Australia). APSF Newsletter 1988; 3:23.
6. Quality assurance in anesthesiology. Guidelines of
the German Society of Anesthesiology and Intensive Care Medicine and of
the Professional Association of German Anesthetists (in German). Anaesth
Intensiv med 1989; 30:307-14.
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Loud Alarms Can Cause More Harm Than Good
To the Editor:
I wish to initiate a discussion among anesthesiologists regarding the design of alarm in currently available operating mom monitoring system. I am specifically concerned about monitoring systems with auditory alarms which are loud, continuous, overly sensitive, and impossible to silence quickly and easily with minimal loss of attention.
Perhaps I am uniquely sensitive to auditory alarm signals, but I find it incredibly distracting at the end of a procedure when I am concentrating on my patient's emergence to have a loud alarm go off telling me something that I already know, such as my patient isn't breathing. I know my patient isn't breathing, because I'm purposely hypoventilating him or her to allow the return of spontaneous ventilation; yet this machine starts screaming, needlessly distracting me and everyone else in the room. I find it very difficult to ignore this persistent noise, and silencing it is often difficult and further distracting.
Hearing is an extremely important sense technologically, serving as our early-warning system for dangers coming from any quadrant. Our sense of hearing does not sleep (even under anesthesia), does not disappear with a turn of the head, and cannot be conveniently turned off or ignored. When deep in thought or wishing to concentrate, how many times have each of us scolded our children or others in the immediate vicinity for noisy activities which interrupt that concentration? How many of you or your surgeons enjoy loud music blaring in the operating room during critical or even simple procedures? Sound is truly a distracting influence and unrelenting, obnoxious sound can be so distracting as to be dangerous.
'Pleasant' Tone Sought
I have a suggestion regarding alarm systems which I would like to propose, and I would welcome comments from fellow anesthesiologist, equipment manufacturers, and experts in the field of monitoring. I propose that critical alarms consist of an initial series of three pleasant tones of sufficient loudness to attract attention, followed by a continuous flashing bright visual signal which remains on until the alarm condition no longer exists or until an appropriate reset switch is activated. I would concede that the auditory signal might repeat every 60-90 seconds, but I am vehemently opposed to any auditory alarm signal in the operating room which is unrelenting until addressed.
I wish to stress that such intermittent auditory signals are appropriate in the operating room for several reasons: 1) the patient should never be alone in the operating room under any circumstances, and, therefore someone will always be right there to notice the alarm condition; 2) in the vast majority of instances in my own experience and that of my colleagues the alarms sound for inappropriate conditions (such as during periods of purposeful hypoventilation at the end of a procedure or when the breathing hoses are removed from the circuit at the end of a case and the oxygen sensor set to alarm at 30% is now exposed to room air; 3) and most importantly, when a situation exists in which the patient's safety is truly in question, the last thing the operative team needs is the distraction of an obnoxious auditory alarm relentlessly hindering their ability to think.
I would be most interested to know if others share my frustration and concerns. I am truly frightened that systems which have been so carefully designed to assist us may actually hinder us at the most critical tunes when our attention should be totally focused on the patient and not on a loud noise emanating from a machine.
Gary L. Fanning, M. D.
The McFarland Clinic, Ames, IA
Concerns Raised About CVP Recommendations, Placement Technique
To the Editor:
The September, 1989 article "Central Venous Catheter Safety Guidelines Issued by Task Force" may be questioned by our neuro anesthesia colleagues.
The recommendations suggested that except for pulmonary artery catheters, the catheter tip should not be placed in the heart. In sitting position craniotomies central venous catheters are always placed in the heart deliberately to aspirate air in the event of an air embolism. Whoever made the recommendations did not consult with our neuro anesthesia brethren. As a result, these recommendations could leave us in a medico-legal pickle
Also, is it now mandatory to use a gown for central venous catheter insertion? I have not worn a gown for these, nor have I had an infected catheter. Is this the new standard of care?
Lee A. Balaklaw, M.D. Cortland, NY
Editor's note: Replies and suggestions are welcome.
ASA Peer Review Group Publishes Model for Judging Clinical Competence of Anesthesiologists in Fair Manner
by William L. Collins, M.D.
The American Society of Anesthesiologists Committee on Peer Review (the Committee) believe that the peer review process and quality assessment and assurance activities are an integral part of any effort to maximize patient safety and minimize patient risk in the medical setting. Patient safety is dependent upon high quality care provided by competent practitioners in an environment that is capable of supporting their efforts.
The Committee is currently recommending a model for evaluating clinical competence of individual providers of anesthesia care developed by Dr. Terry Vitez and initially employed in several hospitals in Los Vegas, Nevada. This model is the first example that we found that provides a measure of quantification to what has previously been a qualitative judgement. Others are currently in use as well and are successful.
There are three basic tenets to the system: competence is a human decision; outcome is the best indicator of competence; and humans are inherently fallible. This loop describes a system that may be suspect because of our human fallibility in making decisions about competence. Yet, we believe that a system that incorporates objective methods for evaluating quality of outcome with quantitation of outcomes from large groups and then comparison of individual performance against the group standard can be an effective way to determine competence.
Trying to briefly summarize the system is perhaps to do it a disservice, however attempt will be made. The basis for the methodology is analysis of outcome as evidenced by a continual collection of data that reflects results of care as provided by individuals and the ability to compare individual outcomes with those of the group. The data collection enables identification of the conditions (e.g. healthy adult herniorraphy vs. premature neonate congenital cardiac defect repair) and sets minimal acceptable standards (ASA Class I patients should not suffer organ damage).
Each individual "incident" (questionable outcome) is analyzed to determine if an "error" involving anesthesia has occurred. The severity of the "negative outcome" is determined and assigned a "negative outcome score" (NOS) from 0 to 10. For no sequellae, the NOS = 0; if an escalation of care occurs, NOS= 1-3, (e.g. post anesthesia verification because of relaxant overdose); if "reversible organ damage" occurs, NOS = 4-6 (e.g. pulmonary edema from fluid overload, corrected by diuresis, irreversible organ damage" (e.g. stroke) has NOS 7-9; and death, NOS = 10.
If an "error" is determined to have happened, its nature is examined. Was it technical (action taken not the intended action, e.g. arterial puncture rather than venipuncture); judgmental (action taken was the intended action, e.g. mask anesthesia for a parturient who had just finished a "Big Mac"); or a lack of vigilance(inaction for lack of attention, e.g. exsanguination from a disconnected arterial line).
The decisions about anesthesia involvement, yes or no, and if yes, the relative severity of the outcome, the nature of the "error" (if there is indeed one) are human decisions made by a subcommittee of knowledgeable anesthesiologists who are usually part of the evaluated group. Anonymity is maintained by trained staff support extracting the pertinent data for presentation to review.
If an error is determined to have been made, discussion elucidating its nature and methods for future avoidance are included in the report. Decisions are in turn evaluated by the group as a committee as a whole. Each individual's performance is periodically tabulated and compared to the larger group's in response to questions about competence or as an aide in the reappointment process. Computer software is available that enables us to accumulate the data and display it as raw data, relational display or graphically. Experience has shown that individuals can be perceived as "bad news" yet performance analysis shows them to be competent, maybe not your choice dinner companion, but competent. Some have shown general group needs for education , e.g. a need for new simulator monitoring of muscle relaxant usage.
Finally, there are those unhappy cases in which a colleague is found to be incompetent, usually not based upon a single human error, that could happen to any of us under some circumstances, but rather on a pattern of poor or questionable outcomes that do not compare favorably to other similar providers. The methodology now allows us to quantitate the severity of these outcomes and objectively analyze why they happened. When these analyses are performed by one's colleagues or a comparative group, true peer review has been done.
Is the system perfect? No, not by a long shot. Is it an improvement over what was there? Yes, vastly! Will there be further improvements? Work is in progress, data being collected and used to constantly upgrade the system. The ASA, at a nominal charge, has available a publication that discusses the issues involved in peer review (see adjacent box) and includes a comprehensive description of Dr. Vitez's program.
The measure of individual competence is but one, albeit very important, factor in providing safe and risk free care for our patients. The review of quality care is a comprehensive process, encompassing a variety of issues. It should be and is undergoing constant review and revision by many different parties, some our fellow anesthesiologists, often with medical expertise and, unfortunately, some with little concern beyond a simplistic desire to limit the cost of care.
The burden is upon ourselves to continue to demonstrate our commitment to provide high quality anesthesia care that is safe and as nearly risk free for our patients as possible and to show by objective means that we are meeting that commitment.
Dr. Collins, Olympia, WA is Chairman of the ASA Peer Review
Drug Labels Cause Continued Concern: Look -Alikes Cause Drug Administration Mistakes
To the Editor.
In Dr. D. L. Lees' Letter to the Editor, "Drug Accident Shows Need for Label Standards:' he suggests the use of properly color-coded ASTM/ D4267 anesthesia standard drug labels and relates the hazards of suddenly appearing nonstandard labels.
Another important aspect to this whole problem is drug packaging and labelling. It appears that the whole pharmaceutical industry is indifferent to " issue. Driven by economic, proprietary, and patent considerations, new vials, ampules, variously colored flip tops, and different labels appear and disappear in anesthesia carts. The look-alikes approach the unbelievable. Succinylcholine looks like Cefazolin; Bacteriostatic Water is like Neostigmine; Glycopyrrolate and Furosemide are like Droperidol; the list is endless and ever-changing.
It is unfortunate that the presence and rapid turnover of look-alikes have led to a significant increase in medication errors. Succinylcholine mixed with Marcaine injected into the epidural space, Norcuron mixed with Neostigmine, Epinephrine mistaken for Regonol all these haw occurred, to name only a few.
The exhortation "You should have read the label " is about as useful as "You shouldn't have run into that tree along the side of the road." Everybody knows about the importance of reading labels; yet, medication errors occur infrequently but regularly, and they may be on the increase for reasons beyond the anesthetists' control. The problem may very well have the dimensions of a major public health issue which could he much ameliorated by a cooperative pharmaceutical industry willing to adopt ASTM labelling standards for ampules, vials, and flip tops.
Hans Hasche-Kluender, M. D.
Swedish Hospital Medical Center Seattle, WA
U.K. Rules Against (!) Vial Colour Coding
To the Editor:
My colleagues and I are interested in safe practice in medicine, in particular in anaesthesia. We found your letter in the APSF Newsletter, Volume 4, No. 3 regarding colour coding of drug ampoules very interesting indeed. We realise that tins issue has been discussed in the past but we feel that it is important to re-open the debate. We have written to the various pharmaceutical manufacturers suggesting that they should distinguish their products with colour-coded labelling.
We were amazed to be informed that the Department of Health in the United Kingdom has adopted a policy against any colour-coding of drug ampoules. The manufacturers are therefore reluctant to colour code their products as it would jeopardize their sales contracts with the National Health hospitals. One company actually colour-coded their products a few years ago but had to revert to their old labelling when they lost their contracts.
The stand of not colour-coding was taken by British authorities presumably because of the fear that this will result in lax practices with staff not reading the labels of the agents they are administering and relying excessively on the visual cues of colour. This opinion is also supported by the Royal Pharmaceutical Society of Great Britain. This point of view appears unfounded as colour-coding is internationally used for medical gases as well as for distinguishing electrical wiring with the aim of avoiding concision. Couple this with the fact that critical incidents with the administration of incorrect medication continue to occur, we feel that this issue must once again be addressed.
We were gratified to read that standards for the colour-coding of drug ampoules are being adopted in the United States. We would like to see similar standards adopted in the United Kingdom if not internationally
Dr. Wilson Lim M.B., BS. Department of Anaesthesia Royal Hallamshire Hospital Sheffield, England
Far Fewer Closed Claims Available; Director of Study Calls for Help
To the Editor
It seems that the focus on patient safety by our profession in the past five years has resulted in fewer claims for anesthesia-related malpractice. Among the evidence for this is the fact that the ASA Committee on Professional Liability is now encountering difficulty obtaining dosed claims to review for the ASA Closed Claims Project. As we have been contacting our sources of closed claims for follow-up visits, we have found that they have not accumulated enough claims to make a reviewer visit worthwhile.
We would appreciate hearing from any of your readers who are in positions of influence in organizations which have closed anesthesia malpractice claims which could be made available in our committee for study.
Clearly this reduction in the number of claims implies to our committee that anesthesia is becoming safer for our patients. Our committee's problem of fewer claims to review is a good problem to have.
Fred Cheney, M. D. University of Washington Seattle, WA
Editor's note: The suggestion in Dr. Cheney's letter of fewer malpractice claims relates directly to the above debate on whether mortality due to anesthesia has decreased. Various recent stories in the APSF Newsletter regarding reduced malpractice insurance premiums for anesthesiologists corroborate the suggestion that them are fewer claims today.
APSF Thanked for Grant Support of Key Study
To the Editor:
As a follow-up to the award which I received from the Anesthesia Patient Safety Foundation in 1987, 1 am providing an update on the progress we have made on our research project The Canadian Four Hospital Study on Anesthetic Outcomes.
The pilot phase for this study was funded by the APSF and subsequently we were successful in obtaining a larger operating grant from the Department of Health and Welfare, Government of Canada. The work which we were able to perform during the period of the APSF funding enabled us to complete feasibility studies and thereby placed us in a position to acquire the larger grant.
At the time of this writing, we have successfully gathered data on 3 5,000 anesthetics administered at four Canadian hospitals and we are presently analyzing the volumes of data. We hope to present the results at an international meeting later this year. I think the results will prove very interesting and valuable for the field of anesthesia safety.
Once again, on behalf of my coinvestigators, Drs. Peter G. Duncan, W. D. B. Pope and W. A. Tweed, I would like to thank the Anesthesia Patient Safety Foundation for generously supporting our work and ensuring the success of our endeavours.
Marsha M. Cohen, M. D., FRCPC University of Manitoba Winnipeg, Manitoba
Jet Ventilator Safety Questioned
To the Editor:
In his recent article on the choice of tracheal tubes for laser airway surgery (September, 1989 Newsletter), Dr. Saunders has mentioned the technique of Venturi jet ventilation without adequately discussing the complications of this technique. The Venturi technique may allow for pulmonary ventilation without the presence of a tracheal tube and thus should decrease the possibility of an airway fire.
However, jet ventilation may not assure adequate ventilation in those patients who are obese or have decreased lung compliance. let ventilation may also be ineffective if an airway obstruction is present or if the jet is not aligned with the trachea. The high pressure of the jet may cause barotrauma(1) including pneumothorax, (2) pneumo mediastinum pneumo peritoneum, subcutaneous emphysema or gastric dilatation
An additional consideration in the use of jet ventilation is that & absence of a cuffed tracheal tube provides no barrier to the aspiration of gastric contents or debris from surgery. Movement of the vocal cords may occur during jetting which may interfere with surgery.
Mitchel B. Sosis, M. D., Ph. D.
Indiana University Medical Center Indianapolis, IN
1. O'Sullivan TJ, Healy GB Complications of Venturi jet ventilation during micro laryngeal surgery. Arch Otolaryngol 111:127-131,1985.
2. Oliverio R, RuderCB Ferman C, Cura A. Pneumothosecondary to bafl-valve obstruction during jet ventilation. Anesthesiology 5 1:255-256, 1979.
3. Chang IL, Meluwis H, Bleyaert A, Babinski M, Retruscak 1. Severe abdominal distention following id ventilation during general anesthesia. Anesthesiology 49:216, 19 7 B.
Is This PACU Practice Patient Abandonment?
To the Editor:
I have been following the controversy of "abandoning" patients in the OR under various circumstances. My practice circumstances are perhaps not unique I would appreciate comments and guidance l am part of a three physician group with three operating rooms. Ordinarily we work with two nurse anesthetists and there is a supervising anesthesiologist free to deal with emergencies. However at certain times of the year we are without nurse anesthetists. At that point no anesthesiologist is free except between cases, and each anesthesiologist is committed one-on-one to an operating room. Similar situations would exist in an all-M.D. group.
Our current practice mode is to only bring patients who are extubated and breathing well and maintaining their own airway to the recovery room. Our problem rate in the recovery room is very low, and usually revolves around giving medications for pain or nausea or discharging patients from the recovery room. On rare occasion we may have to order vapoepinephrine or humidified oxygen for a "croupy" post tonsilectomy patient. We endeavor to only bring stable patients to our recovery room, and we will if necessary stay with our patients in the operating room until we judge them to be stable
My understanding of the standards of care in the recovery room is that once the anesthesia personnel have turned over a stable patient to the appropriately trained and credentialed operating room nurse and given an appropriate turnover report, they are free to return to the operating room. Under such circumstances we do not have an anesthesiologist free to deal with an emergency in the recovery room until another case ends. Most of our cases are fairly short with rapid turnovers, until the afternoon, by which time when we are involved in longer cases, one of our colleagues are free. Does this meet the standard of care?
As a secondary consideration to prior discussions of this issue, I would never consider leaving an operating room to go to the recovery room to deal with a cardiac arrest, unless I had trained anesthesia personnel to relieve me. Even a patient who is awake having cataract surgery under local anesthesia can get into trouble at a moment's notice. We have had sudden cardiac dysrhythmias or ST segment changes develop without warning, which required immediate intervention. We have also had patients develop panic attacks under the same circumstances. Furthermore, should a cardiac arrest develop in the recovery room, while I am in the operating room with another patient, the cardiac arrest team could always be called. In our institution, the team is lead by an emergency physician who can intubate, as well as ICU nurses, a nursing supervisor, and respiratory therapists (and a recovery room nurse) who are all skilled at basic airway management techniques.
I still consider leaving a patient in the operating room to attend to a patient in the recovery room abandonment, and I will not do it unless there are trained anesthesia personnel to take my place. I have been known, however, to run (and I do mean run) into our operating room's central core to pull in supplies that I need. I only do so on stable patients. Under those circumstances I am away from the head of the table for under thirty seconds. I do not necessarily consider this to be abandonment since our central core and supplies am only a few feet away. By the same token when I am doing a spinal I am at times of necessity facing away from my monitors for periods far longer than thirty seconds. I do not consider this to be a breach in the standard of care since I know all of our colleagues are in the same boat.
I would think that our practice mode meets the standard of care. It has allowed us to function in what I think is a safe and effective manner. I do not think we meet Dr. Fletcher's standards (APSF Newsletter, Sept., 1989). However, I do not think based on my understanding of current standards that not having anesthesia personnel immediately physically available in the recovery mom is a breach of care when trained recovery room nurses are present to care for stable patients. We are immediately available for consultation with the recovery room nurses from the operating room. Do all M. D. groups in private hospitals always have an M. 0. free to care for recovery mom problems? That may be financially feasible in a large group, but it is not in small hospitals such as ours.
Any thoughts, comments, or guidance your readership can provide would be greatly appreciated.
Lee A. Balaklaw, M.D. Cortland, NY
Old Equipment: PEEP Safety Cited
To the Editor:
I was very pleased to see in the December 1989 APSF Newsletter a very helpful and timely article relative to the use of older or faulty anesthesia equipment.
In Ms. Nichols' article, she outlined some features of anesthesia machines and delivery systems which, on older equipment, warranted closer scrutiny to avoid the occurrence of hypoventilation.
Even in today's modern anesthesia equipment, additional monitors and other safety enhancements are still no substitute for vigilance on the part of the user. This is particularly true where older machines are used. For this mason, I wished to comment further on the use of PEEP valves in connection with these older machines.
It is quite true, as Ms. Nichols states, that the use of external PEEP valves in has on occasion proved hazardous, particularly when the device used was of a unidirectional type. The unidirectional PEEP valve does, indeed, leave too great a possibility for inappropriate placement. Constant vigilance in each successive use of the device is essential in preventing the catastrophic results of incorrect placement of the unidirectional PEEP valve
Integral PEEP values on modern machines require a similar vigilance as well. The possibility always exists that the feature may be left on, as she emphasized, and that the consequences may be serious for the patient who would not tolerate application of PEEP Further, in servicing the integral PEEP valve, the possibility of misassembly creates an unnecessary exposure to liability on the part of the service technician, the anesthetist, and the hospital.
Several types of bidirectional PEEP valves are currently available on the market and provide a welcome relief from the dangers of misapplication and liability. In the case of reversing the prescribed direction of " type of valve relative to the flow of gas, the PEEP feature is merely bypassed, with no danger of gas-starvation. further, these devices are easier to maintain and service (and at reduced cost) particularly when compared with state-of-the-art integral PEEP system.
Technical Services Coordinator Arnbu, Inc.
To the Editor:
The review of the hazards of older equipment by Ms. Nichols in December's issue was very good. However, I feel that an error was made regarding the effect of high gas flows on the capnographs from a machine with an incompetent expiratory valve if flows are high enough, the inspiratory value for carbon dioxide will return to the baseline. This can be confirmed in everyday practice by preventing the proper seating of the expiratory valve with a small piece of folding paper, or, in the extreme, by removing the valve altogether. When the flow rate is varied, one can observe the changing capnograph.
The above findings should not be surprising, since a circle system will behave much like a Mapleson D system, the latter of course having a capnograph highly dependent on gas flow.
Joseph Antognini, M. D.
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The Committee on Peer Review (CPR) is a standing committee of the ASA whose composition and charge are stated in the ASA Bylaws. Our primary responsibility is assisting ASA members to demonstrate the high quality patient care they provide. We work to develop systems for the measurement of quality of care that can be used by departments of anesthesiology to meet the standards of the Joint Commission on Accreditation of Healthcare Organizations (JACHO), as well as the needs of government entities and other third party payors for care
The CPR concerns itself with the relationship between anesthesiologists and the institutions in which they provide cam such as credentials for medical staff membership and delineation of clinical privileges, the measurement of the outcomes of cam and the evaluation of clinical competence of individual practitioners. The purpose of these activities is not to threaten the anesthesiologist, but rather to offer support for the high quality of anesthesia care provided by the vast majority of us. If poor quality care is being provided, we have a public obligation to identify and correct it.
The CPR is responsible for the publication of an ASA document entitled Peer Review in Anesthesiology which provides a resource for the peer review process as well as information concerning the role of the anesthesiologist in institutional environments. The booklet is available at nominal cost from the ASA Executive Office and can be a valuable asset in consideration of a practice location. The chairman of the CPR or committee members can be contacted through the Executive Office (5 1 5 Busse Highway, Park Ridge, IL 60068-3189,(708)825-5586)to answer questions.
The committee structure of the ASA is designed to assist
the membership, both active and resident, in achieving their goals. Without
input and questions from individual anesthesiologists, some of the purpose
of the Society becomes irrelevant. Involvement is most desirable; maybe
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by N. Ty Smith, M. D.
The main news related to STA involves the meetings sponsored by it and its sister societies,The European Society for Computing and Technology in Anesthesia and Intensive Care the Japanese Society for Technology in Anesthesia, and the Life Support Technology Society (Japan).
First, we would like to remind you of the first Annual Meeting of the Society for Technology in Anesthesia (STA 9 1), to be held January 18-20, 1991, near Epcot Center and Disney World, Florida, at the Govesnor Resort Hotel.
The meeting itself will feature scientific presentations, three tutorial sessions, and a distinguished lecture. Both oral and poster presentations are welcome; the latter can be scientific demonstrations of equipment, software, etc. THIS ANNOUNCEMENTSHOULDBECONSIDERED A FINAL CALL FOR ABSTRACTS. All abstracts should be sent to Dr Kevin Tremper Chairman, Scientific Committee, STA 9 1, c/o Department of Anesthesia, Bldg. 53, Rm 22 7, Rt 8 1 A, UC Irvine Medical Center, I 0 1 City Drive South, Orange, CA 92668. The deadline for abstracts is August 1, and there is no special format for them. The limit is 250-500 words, plus illustrations and tables. Abstracts will be published in the Journal of Clinical Monitoring.
Future of Monitoring
We have already described the tutorial panels and Distinguished Lecture, but they bear repeating. The topic for the fire set of tutorials is "What's Next in Monitoring." During this session, Michael Cahalan will speak on Echo, Doppler, and TEE; Ira 1. Rampil on CNS Monitoring; and Stephen Barker on lntravascular Blood Gas Electrodes. On the following day, there will be a tutorial panel, entitled "The Uncertainty Surrounding Clinical Measurements," chaired by 1. S. Gravenstein. The major questions asked will be "How accurate can we hope to be with our monitoring?" and "How accurate do we need to be?" The speakers will be Allen Ream, Blood Pressure; John Sevoinghaus, Pulse Oximetry; David Swedlow, Respiratory Gases and Inhaled Agents; and Terry Vitez, Electrolytes. A third tutorial will be run by CLASS and will address the question, " How Can Technology Help Me Give Anesthesia Via a Closed Circuit?" Drs. Jerry Calkins, Alan Grogono, Gilbert Ritchie, and Dwayne Westenskow will be in charge of this section of the meeting. The Spacelabs Distinguished Lecturer will be Dr. Richard Kitz, who will discuss the subject, "Does a Technological Education During Medical School Make Better Doctors?"
STA is making" every effort to make its resources available to its members, as well as those interested in its goals. This philosophy is reflected in
STA 9 1. We want to make it financially as easy as possible to attend. For example registration fm are only $ 150 for members and $250 for nonmembers. In both cases, registration includes a reception, most meals, coffee breaks, registration materials, and the meeting itself. Nonmember registration includes a year's membership; the $2 5 application fee is waived. In addition, the Grovesnor Hotel provides a frequent shuttle service to the major attractions of the area: Epcot Center, Disney World, and the MGM theme park. Thus, participants need not rent a car.
A special inexpensive, but exciting, tour is scheduled for the day before and after the meeting (Thursday,January 17 and Monday January 2l).We have arranged for a "behind-the-scenes" tour of the Kennedy Space Center, including the computers, animal facility, and laboratories.
Globetrotting Anesthesia Technology
In addition to STA '91, don't forget the other meetings cosponsored by STA. These include the First Annual Meeting of the European Society for Technology in Anesthesia and Intensive Care, to be held on October 24-27, 1990, in Salzburg, Austria. Another meeting cosponsored by STA is the 6th International Symposium on Computing in Anesthesia and intensive care to be held in Hamamatsu, Japan, April 15-20, 199 1. Contacts for these meetings are as follows. STA '91: Ms. Gerri Kuzava, P. 0. Box 382, Hastings, MI 49058; Ist ESTAIC: Dr. Leo Moser, Anaesffiesiologie, L-andenkrankenhaus Salzburg, Mullner Huptstrabe 48, A-5020 &31zburg, Tel 0662/31581-2701. 6th ISCAIC: either Dr. Kazuyuki Ikeda, Chairman, Department of Anesthesiology, Hamamatsu University, School of Medicine, Hamamatsu 43 1-3 1, Japan, or Dr. Yasuhijro Fukui at Department of Applied Engineering, Tokyo Denki University, Hatoyama Saitama 3050-3, Japan.
ASA: QA at STA
If you attend the ASA Meeting in Las Vegas, October 19-23, 1990, be sure to save time to attend STA's second Breakfast Panel. This year's topic will be "How Can Technology Help Me with Quality Assurance?" Anything that can make life easier and fairer in this difficult area will be welcome, and the group of outstanding panelists promises to do just that. The panel will be moderated by Dr. John Eichhom, and will include Drs. Jerry Cohen and Terry Vitez.
An Alarming Dinner
Finally, also at the ASA Meeting will be a Saturday night dinner meeting (October 20), with a special panel jointly sponsored by STA and the AAMI Human Engineering Committee. The panel will explore alarms from the manufacturer's and the user's point of view. It represents a superb opportunity for both sides to be heard - for the manufacturer's to pass on their ideas, but more importantly for the user to sound off and say what is wrong and how the situation might be improved. Who knows - some sort of consensus might even be reached. The panel will be moderated by Christopher Goodrich and Dr. Frank Block, and is expected to be very interesting and unusual.
Plan now to attend these important meetings. Dr. Smith, Veterans Administration Medical Center,
Department of Anesthesiology, San Diego, CA, is President
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Zeitlin GL: Possible decrease in mortality associated with anesthesia, A comparison of two time periods in Massachusetts, USA. Anaesthesia 1989; 44:432A33.
Epidemiology is increasingly recognized as a useful research tool in anesthesiology. Ultimately, the specialty's safety record and its improvement over time can be documented only with epidemiologic data involving mail numerators and large denominators, both of which are counted accurately. By attempting to pin down the anesthetic mortality rate at two points in time (circa 1960 and circa 1980), Zeitlin has demonstrated some of the pitfalls and frustrations in trying to collect useful epidemiologic data.
For a baseline, the author cites a previous study of anesthetic mortality' in the years 1955-64 which demonstrated a mortality rate of 2.16 per 10,000 anesthetics. This irate was based on a numerator of 15 primary anesthetic deaths observed in a busy private practice in Massachusetts, and a denominator of 69,291 anesthetics from which the 15 deaths were drawn. It is noteworthy that other roughly contemporaneous studies found similar rates. For instance, Harrison2 reported an anesthetic mortality rate in South Africa of 2.2 per 10,000 for the period of 1967-76. So far, so good; we have a nice piece of epidemiologic work, with results comparable to those of other workers.
Regarding the more recent past: Has the anesthetic mortality rate improved since 1960? Using data from Massachusetts two decades later, Zeitlin attempts to answer that question, citing a dramatically lower figure of 0. 1 6 deaths per I 0,000 anesthetics. For the numerator (number of deaths), he drew data from a Massachusetts malpractice insurance company, counting 31 claims involving deaths due to anesthesia between the years 1977-84. But because insurance companies don't count denominators (they record failures, not successes), Zeitlin" could only estimate the number of cases from which the numerator came(that is, his denominator)to be 800 anesthetics per insured anesthesiologist per year, or 1,920,000 anesthetics.
This is not good epidemiology, as Zeitlin, to his credit, admits. Estimating the denominator cannot substitute for counting (A lession for anesthesiologists who want to do epidemiology-. Counting denominators is just as important as counting numerators, and a lot harder). Worse yet, the numerator hem is not the number of deaths, but the number of malpractice claims resulting from those deaths. The assumption that all deaths result in claims is hardly credible, even in Massachusetts. (the lesson here: data from malpractice claims studies, while useful in themselves, cant be compared with clinically derived numerators.)
The admittedly shaky assumptions of the second Part of Zeitlin's study might be justified as an attempt to test an hypothesis for which frustratingly little direct evidence currently exists: that anesthesiology is Setting safer. Moreover, a result of 0. 16 deaths per I 0,000 would be believable in the context of other studies with similar results. Unfortunately, other studies of anesthetic mortality in the late 70s and early 80s (from Finland3, Canada4 and France5, for example) have continued to report mortality rates of approximately I to 2 per I 0, 000. Zeitlin's recent mortality figure--, an order of magnitude smaller than those of other contemporaneous studies, may be therefore literally "too good to be true."
Zeitlin's report to the contrary, there is evidence pointing to an anesthetic mortality rate of I or 2 per I 0,000 even possibly up to the mid-1 980s. Anestheliogists have very good reason to believe that the rate has fallen within the past five or more years, but no concrete epidemiologic proof. We will not have that proof until good epidemiologic studies of contemporary practice make their way into print.
1 Memery HN:Anesthesia mortality in private practice. A ten year study. JAMA 1965; 194:1185-8.
2. Harrison GG:Death attributable to anesthesia. BiI Anaesth 1979; 50:1041-1046.
3. Hovi-Viander M: Death associated with anesthesia in Finland. Br I Anaesth 1980; 52:483-9.
4. Duncan, PG: Postoperativecomplications: factors of significance to anaesthetic practice Can I Anaesth 1987; 34:2-8.
5. Tiret L, Desmonts JM, Hatton F, Vourc'h G: Complications associated with anaesthesia a prospective survey in France. Can Anaesffi Soc 1 1986; 33.-336-44.
Review by Richard L. Keenan, M.D., Professor and chairman of Anesthesiology at the Medical College of Virginia, Richmond, and epidemiologic investigator of cardiac arrests during anesthesia care.
Editor's Note: Dr. Zeitlin replies."Dr. Keenan's review is fair comment, but please note further that two recent studies also suggest a rate of mortality attributable solely to anesthesia care dramatically lower than 1-2 per 10,000. The British CEPOD)
study1 and also the review of the Harvard Medical School data before and after the adoption of the monitoring standards' both showed an anesthesia caused mortality of 0.05 per 10,000 patients."
1 Lunn YN, Devlin HB: lessons from the confidential enquiry into P-ostoperative deaths in three NHS regions. L-ancet 1987; 2:1384.
2. Eichhom JH: Prevention of intraoperative anesthesia
accidents and related severe injury through safety monitoring. Anesthesiology
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by Alex Gerwer
A review of the advertisements found in the various anesthesiology journals reveals a consistent underlying theme among manufacturers: that the monitoring device or devices which are featured in a particular advertisement will serve to improve the ability of the anesthestist to deliver anesthesia. Reviewed here are some industry trends which led to the advertised claims. Also offered is one view as to what industry might do in the future to fin further respond to demands to help increase patient safety in the operating room.
The success of the pulse oximeter has had a significant influence on the medical device industry. The importance of devices which feature simple operation and address the prevention of anesthetic mishaps has led to a series of new technologies which have achieved relatively rapid acceptance in the anesthesia community. As an example,the catastrophic potential of breathing system failures has led to a variety of products with technologies aimed at measuring physiologic paraneters such as mixed venous oxygen saturation and end tidal carbon dioxide. These physiologic parameters aid in the assessment of the adequacy of tissue oxygenation and patient ventilation.
With the advent of new devices for monitoring in addition to the monitors which have been widely used for many years, the anesthesia community has started work to develop methods of organizing the resulting large array of independently functioning displays and alarms. Companies in the medical device industry are working actively with anesthesiologists on organizing the mass of data from monitors in ways which facilitate the rapid recognition of critical incidents by anesthetists.
Several companies have recently introduced products which show some of the fruits of this work in the form of novel display formats and integrated alarm systems. In addition, many companies are cooperating in the formulation of a standard aimed at allowing monitoring devices in the operating room to communicate with one another and share information. This standard, called the Medical Information Bus, once approved, will provide further opportunities for device manufacturers who are working to improve data displays and alarm enunciations in the future.
In the future, industry will continue to focus on technologies to provide products to the anesthetist which will improve patient safety during anesthesia. It is recognized that devices will never replace the expertise of the clinician, but it is also acknowledged that products can be good "electronic assistants " if they are designed with an understanding of what a clinician requires of such an assistant.
It should be recognized that the medical device industry will have to tackle some significant issues in the future. The resolution of these issues will serve to allow manufacturers to provide anesthesia work station which further addresses issues of patient saw. Some of these issues are:
The impeded coordination and management of data by a fragmented industry, an industry where anesthesia machine, cardiovascular monitor, and respiratory monitor companies have evolved largely independent of one another.
The cautions posture maintained by the medical device industry due to the current nature of regulatory and product liability issues.
The difficulty in implementing methods by which dances can handle contextual information. Contextual information consists of data which in intra-operative situations dictates that certain combinations of physiologic parameters are acceptable under one set of clinical circumstances while those same combinations of physiologic parameters are totally unacceptable under other sets of clinical circumstances.
The problems in addressing the prevention, control, and handling of artifactual information.
The medical device industry has learned about what is needed to help maintain anesthesia patient safety from the clinician. In the future, the anesthetist" will continue to be a critical source of input for medical device companies who seek to implement new ways of helping to improve patient safety. Organizations such as the Anesthesia Patient Safety Foundation serve as an important link between clinicians and industry who are together engaged in shaping "electronic assistants" for the anesthetist in the operating room.
Mr. Gerwer is Manager, Product Research Group; Nihon Kohden
America, Inc., Irvine, CA.
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With the aim of contributing to the optimum safety of anaesthetized patients, the French Society for Anaesthesiology and Intensive Care (SFAR) recommends monitoring principles set out in this document. Monitoring should be employed whenever general anaesthesia, regional analgesia, or sedation is performed for a therapeutic or diagnostic procedure. Monitoring during obstetric analgesia will be the subject of specific recommendations. The recommendations apply to staffing and to monitoring of both patient and anaesthetic apparatus. To this basic clinical and instrumental monitoring may be added further measures depending on the condition of the patient, the nature of the procedure and the anaesthetic requirements. In an emergency it may not be possible to implement these recommendations in full. Monitoring by competent personnel is also necessary during transfer of a patient to recovery ward, dependency unit, or intensive care unit. Monitoring in the recovery ward will be the subject of specific recommendations.
General anaesthesia, regional analgesia and intravenous sedation must be performed by, or in the presence of a qualified anaesthesiologist This may be a doctor who has completed specialist training in anaesthesiology, or one undergoing such training provided his or her competence is appropriate to the procedure being performed. In certain situations (particular operation and/or patient at high risk) other doctors may need to be present.
The anaesthesiologist may be helped by a doctor undergoing specialist training and/or an anaesthetic nurse. These assistants are not entitled to perform anaesthesia in the absence of an anaesthesiologist. Their roles are confined to those of surveillance and assistance.
The anaesthesiologist may have to leave the operating mom for a brief period and entrust the monitoring of patient and apparatus to a trainee and/or anaesthetic nurse. Nevertheless the anaesthesiologist remains responsible for the procedure unless handover has been made to someone suitably qualified.
2. Monitoring of Patient and Anaesthetic Apparatus
During anaesthesia, oxygenation, ventilation, and the circulation are monitored continuously and relevant data are noted in the anaesthetic record.
When the anesthesiologist has to be remote from the patient (particular procedure ionizing radiation, MRI) adequate instrumental monitoring substitutes for close clinical observation.
2. 1. Oxygenation
Monitoring of oxygenation includes: a) continuous measurement of oxygen concentration in the administered gas mixture b) observation of the patient, c) continuous measurement of blood oxygen saturation, or equivalent.
Monitoring of ventilation is based on clinical observation (rate, amplitude and symmetry of thoracic expansion, movements of reservoir bag, auscultation) and measuring devices (expired volume and airway pressure). If expired gas can be collected, the measurement of expired CO2 is recommended.
After tracheal intubation and after every change in the patient's position, correct placement of the tracheal tube is checked.
Monitoring of the circulation comprises assessment of heart beats, heart rate, arterial pressure, peripheral circulation, and ECG.
Heart beats are monitored by palpation of the pulse and/or at least one of the following measures: auscultation of the heart, continuous measurement of arterial blood pressure and pulse oximetry or equivalent technique. The values of head rate and blood pressure are noted at intervals which should not exceed five minutes. ECG monitoring should be saw before induction and continued until recovery.
2.4. Additional Monitoring
During anaesthesia a careful watch is kept on the patient's position, with particular attention to pressure points and areas where risk of nerve damage is high. A further check is made whenever the patient's position is changed.
Central temperature should be measured whenever a significant change occurs or is expected; this measurement is particularly indicated in small children. Monitoring of urine output is indicated during certain types of operation (long duration, following transfusion) and if problems occur with the circulation.
3. Monitoring Equipment
The anaesthesiologist must have available equipment with which he or she is familiar, and whose correct functioning has been confirmed using a check list.
3. 1. Monitoring the Patient:
Every site where anaesthesia is performed should be equipped as follows:
3. 1. 1. Mandatory Equipment:
ECG monitor Device for automatic blood pressure measurement
3.1.2. Recommended Equipment:
3.2. Monitoring the Anaesthetic Machine:
Every anaesthetic machine should be equipped with the following devices:
An oxygen supply pressure gauge situated on the machine or pipeline
An oxygen analyzer connected to the anaesthetic breathing system giving audible warning of low concentration; the presence of safety linkage between N2O and O2 flow controls does not allow this requirement to be waved
During mechanical ventilation, the ventilator must be fitted with warning devices indicating
a) disconnection or leak,
b) excessive airway pressure,
c) ventilator arrest.
3.3. Supplementary Equipment
Other monitoring devices may be indicated depending on the state of the patient, the type of procedure and anaesthetic requirements. They include monitors of temperature, neuromuscular block, and intravascular pressures, anaesthetic gas analyser, and ECG recorder.
At present, the lack of staff and/or equipment in some
hospitals may prevent the full implementation of these recommendations.
In this case SFAR recommends that anaesthesiologists should draw up with
the hospital administration a plan naming a date (no later than 1 st January
1993) by which the necessary staff and equipment will be available
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by Professor J.C. Otteni
The "Societe Francaise d' Anesthesie et de Reanimation" (SFAR)published, in June 1989, "Recommendations for the monitoring of patients during anaesthesia:' These were produced by an ad hoc ,working party consisting of twelve members and accepted by the Council of SFAR. They take in account the standards already proposed or adopted by the equivalent societies of other countries and have been drawn up with regard to French regulations and legislation.
Two important concepts concerning the practice of anaesthesia in France are stressed. As anaesthesia is equivalent to a rapid succession of diagnostic and therapeutic procedures, affects the body's integrity, and carries risks, it should only be performed by, or in the presence of, a qualified anesthesiologist. The roles of trainees and anaesthetic nurses (not equivalent to American C.R.N.A's) are confined to those of surveillance and assistance. The other important point is the fact that the presence of a so-called "02-N20 safety mixer" which is mandatory in France by government regulation, does not allow the requirement of an oxygen analyser connected to the anesthetic breathing system to be waived.
Professor J.C. Otteni is Chairman of SFAR's Working Party and of the Department of Anaesthetics and Sum," Intensive Care, University Hospital Strasbourg-Hautepierre, France.
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by Dean M. Tully, M.D.
The relation of peri-operative blood pressure changes to post-operative complications is complex and controversial. The topic can be divided into three areas:
Post-operative (recovery room) hypertension
Not discussed are causes of technical problems measuring blood pressure
Although chronic anti hypertensive therapy has been shown to reduce much of the morbidity, e-S. congestive heart failure, chronic re" failure, and cerebrovascular accidents associated with hypertension, the evidence linking pre-operative hypertension to post-operative complications is weak. Although Prys-Roberts found that pre-operative hypertensive patients have more blood pressure lability peri-operatively and the treatment of the hypertension decreases this lability, Goldman found no relationship between pre-operative hypertension and post-operative complications. Hypertension is not one of the risk factors in his cardiac risk index.
Goldman's study can be criticized because of an insufficient number of patients with severe hypertension. However, his conclusion that ". . . elective surgery in the absence of ideal anti-hypertensive therapy need not subject patients to added clinical risk provided, a) diastolic pressure is stable and not higher than 110 torr, and b) intra-operative and recovery room blood pressure values are closely monitored to prevent hypertensive and hypotensive episodes. . " has become accepted clinical practice
Historically, the relationship between intra-operative events and post-operative outcome has been tenuous. Rao and El Etra's paper demonstrating a marked decrease in post-operative reinfarction rate also showed a much higher incidence of reinfarction in patients having intra-operative hemodynamic abnormalities, mainly hypertension, hypotension, and tachycardia. In fact, some believe the improvement in the reinfarction rate may have been due to the prevention of these hemodynamic abnormalities rather than the use of invasive monitors.
Keats and Slogoffs study at the Tom Heart Institute showing a relationship between intraoperative ischemia and post-operative infarction also showed that "ischemia was significantly more common in patients who had hemodynamic abnormalities (hypertension, hypotension, or tachycardia) both before and during anesthesia". Hypertension and tachycardia were much more frequent than hypotension, and tachycardia seemed to be most poorly tolerated.
Therefore, there is now a moderate amount of evidence indicating that intra-operative blood pressure changes lead to post-operative cardiac complications and that the dose control of blood pressure peri-operatively will decrease these complications.
Post-operative blood pressure abnormalities are first and foremost an indication to look for an underlying problem. If a patient is hypotensive, hypovolemia and surgical bleeding should be suspected. If a patient is hypotensive, pain, respiratory, failure, hypoxia, bladder or gastric distention, and fluid overload should be considered and the patient examined. Post-operative relative hypertension usually occurs within 30 minutes of surgery and is quite common. Up to 50% of hypertensive patients undergoing surgery -M have postoperative hypertension. Although studies have shown postoperative hypertension to be transient (lasting less than four hours) and generally well tolerated, it is prudent and accepted clinical practice to treat this hypertension in elderly, high risk patients. Labetatol has become a popular, effective and safe first line drug for recovery room hypertension.
Over-all, careful attention to blood pressure management can be an important component of maximizing anesthesia patient safety
Dr. Tully is a staff anesthesiologist at the New England Deaconess Hospital, Boston.
1. Prys-Roberts C. Hypetension and anesthesia fifty years on. Anesthesiology. 1979; 50:281-283.
2. Goldman L, Caidera DL Risk of general anesthesia and elective operation in the hypertensive patient. Anesthesiology. 1979; 50:285-292.
3. Goldman L et al. Multifactorial index of cardiac risk in non-cardiac surgical procedures. NEJM. 1977; 297:845-850.
4. Rao TLK, locobs KH, 11 Etra AM. Reinfarction following anesthesia in patients wtffi nwocanhal mmrchon. Anesthesiology. 1983; 59:499-505.
5. Slogoff W, Keats HS. Does pen-operative myocardial ischemia lead to post-operative myocardial infarction. Anesthesiology. 1985; 62:107-114.
6. Gal 11, Cooperman LH. Hypertension in the immediate post-operative period. Br 1. Anaesth. 1975;47:70.
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The Anesthesia Patient Safety Foundation Newsletter is the official publication of the nonprofit Anesthesia Patient Safety Foundation and is published quarterly in March, June, September, and December 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 Patent Safety Foundation, 1988.
The opinions expressed in this newsletter are not necessarily 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; W. Dekle Rountree Jr., Vice-President; E.S. Siker, M.D., Secretary; Burton A. Dole, Jr., Treasurer; Jeffrey B. Cooper, Ph.D.; Joachim S. Gavenstein, M.D.; James E Holzer, J.D.
Newsletter Editorial Board: John H. Eichhorn, M.D., Stanley J. Aukburg, M.D., Jeffrey M. Beutler, C.R.N.A., M.S., Ralph A. Epstein, M.D., David E. Lees, M.D., Bernard V. Wetchler, M.D., Mr. Mark D. Wood
Address all general, membership, and subscription correspondence to:
Administrator Anesthesia Patient Safety Foundation
515 Busse Highway
Park Ridge, IL 60068
Address Newsletter editorial comments, questions, letter, and suggestions to:
John H. Eichhorn, M.D. Editor, APSF Newsletter; Dept. Anesthesia
Beth Israel Hospital, DA-7 1 7 Boston, MA 02215
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