CO Poisoning During Anesthesia Poses
Puzzles: New Agent Used in Florida Case
Cause of CO Poisoning, Relation to Halogenated Agents Still Not Clear
QA Program Reveals Safety Issues, Promotes Development of Guidelines
Medical Gas Contamination An Unrecognized Patient Danger
Letters to the Editor
First Ever Guidelines Issued in Japan
by Robert E. Lentz, M.D.
Previous reports regarding the diagnosis of carbon monoxide exposure from an unknown source have suggested that there is an interaction of the halogenated volatile anesthetics and the carbon dioxide absorbent in the breathing circuit, particularly when an anesthesia machine which delivered volatile anesthetic then sat unused for a period of time. As new halogenated anesthetics become available and are used, it remains to be observed whether they too will be associated with this apparent phenomenon. Reported here is an instance where this appears to be so.
Report of a Case
A 46-year-old white female was scheduled as an outpatient for septoplasty, endoscopic bilateral anterior ethmoidal sinus surgery, and excision of a left tonsillar cyst. During her pre-op interview, the patient denied any cardiac or respiratory history. The patient also denied any prior anesthetics and she was not taking any chronic medications. The patient did, however, admit to being a smoker, with a 20 pack/year smoking history.
Routine pre-op labs were within normal limits, and specific values were: Hgb 14.1, Na 141, K 3.8, Cl 108, C02 23, and Ca 9.6.
While in the holding area, an intravenous line was placed with D5LR infusing at 100cc/hr. The patient then received glycopyrolate 0.2mg IV with midazolam 2mg IV for sedation. The patient was taken to the operating room where she was placed on the table, positioned, and monitors including NIBP, pulse oximetry, and EKG were placed. The patient was pre-oxygenated and general anesthesia was induced with alfentanil 500 mg, lidocaine 70 mg, atracurium 5 mg (defasiculating dose), propofol 100 mg, and succinylcholine 100 mg intravenously. The patient was intubated with a 7.0 cuffed endotracheal tube under direct vision. The tube was secured at 20 cm at the lips, breath sounds were equal bilaterally, and EtCO2 was noted on the anesthetic gas monitor. The patient was then placed on the ventilator with the settings of TV 600 [email protected], Rate 10, PIP 20 cmH20. An additional 10 mg of atracurium was given IV to complete the balanced anesthetic technique. Prior to induction, the patient's vital signs had been: BP 140/88, Heart Rate 95, SaO2=97% (room air), Temperature 36.5 C. Following induction, the vital signs were: BP 110/60, HR 95, SaO2=100% (FiO2=40%), Temp 36.5 C.
Approximately 40 minutes into the case, the patient's 02-Hgb saturation decreased to 96% over a period of 2-3 minutes. The pulse oximeter probe was inspected to verify proper placement on the finger. Breath sounds remained equal bilaterally, without wheezes, and there was no change in PIP. The endotracheal tube was also checked for its position, and it was noted to still be secured at 20 cm at the lips. At this point, the patient was placed on 100% 02 and hand ventilated with up to 40 cmH20 pressure. This also failed to bring the patient's O2 saturation above 96%. The surgeon was made aware of these findings and was asked to complete the procedure as quickly as possible.
Arterial blood gases were sent to check the 02 saturation a COHb level was also requested. The blood gas report read the following values: pH 7.46; PC02=28 mm Hg; P02 467 mm Hg; HCO3 20.3 MEq/l; COHB 31.5%. At this point, the patient's 02-Hgb saturation remained at 97%. The surgeon was made aware of the new findings, and the procedure was completed over the next 10 minutes. The entire time interval from when the 02Hgb saturation started to decrease to the completion of the surgery was 30 minutes.
It was decided to leave the patient intubated, on 100% 02, and ventilated in the Post Anesthesia Care Unit, until the level of COHB decreased enough to permit safe extubation. In the PACU, the patient was placed on a ventilator with the same settings as were given in the OR with the addition of 5 cmH20 PEEP. The patient arrived in the PACU at 0935 and was noted to be pale and unresponsive to verbal or tactile stimuli. At 0940 the patient became more reactive, requiring midazolam 1 mg for sedation. The 02 saturation by now was 99%. At 1000 another blood gas was drawn, and the results were the following: pH 7.56; pCO2 20 mm Hg; pO2 482.5 mm Hg; HCO3 18.5 MEq/l; COHB 12.4%. The ventilator settings remained unchanged, and at 1030 another blood gas was drawn which showed continued improvement as the COHB level had decreased to 5.3%. At this time, the patient was responsive to verbal stimuli and was able to maintain head lift for five seconds. At 1040, the patient was extubated uneventfully and placed on a venti-mask. The patient maintained her 02-Hgb saturation at 98100% with a respiratory rate of 16 breaths per minute. At 1100 the mask was discontinued and the patient received "blow-by' 02 only. She continued to maintain her 02-Hgb saturation at 98-1 00%.
At 1200, the patient was transferred to her room and monitors were discontinued. At 1800, the last blood gas was drawn, and the results were as follows: pH 7.44; pCO2 37.4, pO2 93.1 mm Hg; HCO3 24.2 mm Hg; COHB 2.6%. The patient was subsequently discharged, and she suffered no adverse sequelae.
Although carbon monoxide production has been associated with the other halogenated agents, this is the first documented case involving the newest inhalation anesthetic. In all of the other cases reported, the anesthesia machines sat idle for longer than 24 hours, the soda lime was not changed prior to the procedure, and the involved case was usually the first case of the day. Our patient was the first case on a Monday morning, and the anesthesia machine (after use of the volatile anesthetic on Friday) had not been used over the immediately prior weekend. Other similarities included the onset time to the desaturation, about 30-40 minutes after induction in all cases, and rapid recovery without injury to the patient.
The US FDA Center for Disease Control recommendations regarding this subject matter are as follows:
* All soda lime that has been dormant in the anesthesia machine for more than 24 hours should be changed, and dated.
* In addition to changing the soda lime, the anesthesia machine should also be flushed continuously with 100% 02 for at least one minute prior to the first case of the day.
In any patient who develops the type of hemoglobin desaturation described here and who fails to respond to the usual therapeutic measures used to correct this problem, do not hesitate to send either a venous or, preferably, an arterial blood sample for the possibility of COHB "poisoning' (see article on page 13).
Dr. Lentz is chairman of the Department of Anesthesiology, Palms West Hospital, Loxahatchee, FL.
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by Richard E. Moon, M.D.
The above case report from Florida appears to indicate that also with one of the newest halogenated volatile anesthetics comes the rare (but previously clearly documented) association with very high levels of carbon monoxide in the patient's blood.
Carbon monoxide (CO) is an odorless, tasteless gas that is usually produced by combustion. Common sources include internal combustion engine exhaust, house fires and barbecues. CO poisoning can also result from inhalation of methylene chloride fumes, as cytochrome P450 in the liver converts this compound to CO. There is a small endogenous production of CO from breakdown of hemoproteins, particularly hemoglobin (M). The toxicity of CO is caused by displacing oxygen from various hemoproteins, including Hb. fib binds CO with an avidity approximately 200 times greater than Oz forming carboxyhemoglobin (COHb). Formation of COHB results in a functional anemia and an additional increase in affinity for 02 of the unbound Hb ('shift to the left" of the Hb-02 dissociation curve), resulting in decreased 02 delivery and impaired extraction of 02 from Hb at the tissue. Additional mechanisms of toxicity result from CO binding to other hemoproteins such as myoglobin and cytochrome oxidase.
Because of its high affinity for target proteins, CO is toxic even in low concentrations. Breathing 1000 parts per million (ppm) for an hour will typically result in a COHB level of around 30% and evidence of moderately severe poisoning. For an eight hour exposure the Occupational Safety and Health Administration (OSHA) has set the maximum limit at 50 ppm. Using data on the effect of low level CO exposure on anginal threshold in individuals with coronary artery disease, the Environmental Protection Agency (EPA) has set the levels at 35 and 9 ppm for one and eight hour exposures, respectively.
Symptoms and signs of CO poisoning include headache, nausea, vomiting, dizziness, motor weakness, impaired consciousness, cardiac arrhythmias and ischemia. In some instances, particularly if there are neurological abnormalities at the time of the exposure, there can be prolonged or permanent sequelae consisting of cognitive deficits, mood changes, dementia and extra-pyramidal motor abnormalities. CO poisoning can also be fatal by preventing normal oxygen delivery to the tissues.
CO poisoning can be diagnosed by measurement of COHB in peripheral blood. COHB can readily by measured using a four-wavelength cooximeter, and is reported as a percentage of total Hb. A typical non-smoker may normally have 1-2% COHB, derived from endogenously produced CO. Smokers may have around 4 7% COHB. Although there is a poor correlation between COHB level and clinical severity of CO poisoning, generally a COHB level greater than 15-20% is associated with symptoms and greater than 50% with impaired consciousness.
CO poisoning during anesthesia is unlikely to be diagnosed using commonly employed monitors. COHB is not easily detected by dual wavelength devices such as pulse oximeters. Studies in dogs' and observations in patients (2) have indicated that high COHB levels result in only a trivial reduction in SaO2 measured by pulse oximetry. Detection of gaseous CO is also difficult. Dedicated CO analyzers most commonly use either electrochemical techniques or infrared absorption. However, the infrared absorption spectrum of CO is different from that of C02, and in concentrations likely to be present in cases of CO poisoning (0.05 0.1%), would not significantly alter the reading on clinical capnographs. CO has a molecular weight of approximately 28, and with commonly used mass spectrometers cannot be distinguished from nitrogen. The only reliable method of detection is direct measurement of blood COHB.
Treatment of CO poisoning includes removal from the source of exposure and immediate administration Of 02. Inspired 02 should be as close to 100% as feasible. Hyperbaric oxygen has been recommended for patients with neurological symptoms, cardiac ischemia, pregnancy or high COHB levels.' In the setting of neurological abnormalities, including temporary loss of consciousness, there is evidence that hyperbaric oxygen may prevent long term sequelae.
Intraoperative Carbon Monoxide Poisoning
The case reported by Dr. Lentz is similar to a number of others which have occurred in at least three other institutions in this country. Our own experience at Duke Medical Center dates back to January of 1990, at which time a 76-year-old nonsmoking female was undergoing general anesthesia for thyroid resection. It is the policy of our Blood Gas Lab to do co-oximetry on all samples sent for blood gas analysis. An arterial catheter had been inserted preoperatively and 25 minutes after anesthesia induction, a routine ABG sample was sent to the laboratory. Carboxyhemoglobin (COHB) level was 9.1%. SaO2 by pulse oximetry was 99 100% throughout the anesthetic. Another blood gas was sent an hour after the first one and the COHB level was 28%. Upon receipt of this result, another sample was sent and the COHB level was 29%. This was confirmed on two other co-oximeters. It was assumed that either the O2 or the N20 supply had been contaminated. The gas supply lines were disconnected from the wall source and the patient was administered 100% O2 from the accessory tank. Subsequent COHB levels were lower. The patient awoke with a headache. Because of the extremely high level and the residual symptom despite 100% 02 administration, she was treated with hyperbaric oxygen with complete resolution of the headache.
Despite the suspicion of source gas contamination, blood values obtained from patients in rooms supplied from the same gas tank lines showed no similar COHB elevation. Immediate measurement of gaseous CO in the supply revealed levels <1 ppm. Additionally, exhaustive investigations in conjunction with the suppliers of 02 and N20 essentially ruled out the possibility of source gas contamination.
The second case became evident about six weeks later when a patient undergoing total hip replacement under general anesthesia had a COHB level of 24.7%. Similar investigations were carried out; no source was found. However, the anesthesia circuit had been left in place and, using an electrochemical CO monitor, it was noted that gas exiting the Sodasorb canister had a CO concentration > 500 ppm. Heating of one of the two soda lime canisters liberated high levels of CO.
Abstract Brings More Reports
A total of eight instances occurred at Duke Medical Center. After publication of an ASA abstract, we were immediately contacted by Dr. Ed Brunner at Northwestern and Dr. Chuck Ingram at Emory, reporting, respectively, three and eighteen similar cases with COHB levels ranging from 8.5 to 32%. Many of the cases had baseline measurements and therefore a documented rise in COHB during anesthesia.
At the 1990 ASA meeting, a meeting was held including representatives of W.R. Grace, manufacturer of Sodasorb, and Anaquest, manufacturer of fluorinated volatile anesthetics. Review of the cases revealed no particular distinguishing characteristics of the anesthetics. Most patients had been administered one of the fluorinated gases with nitrous oxide and some narcotic. One patient had received a spinal anesthetic and had presumably been exposed to CO while receiving supplemental 02 via the anesthetic circuit. There was, however, one interesting factor: most instances had been the first case anesthetized on a Monday morning; all cases occurred in a room which had not been used for at least two days. This raised the possibility that a slow chemical reaction, possibly involving C02 absorbent, was responsible for accumulation of CO within the anesthesia machine.
Although there was no obvious mechanism for the observed cases of CO poisoning, it seemed that the soda lime was probably the site of formation or accumulation, and a set of interim guidelines was developed by Drs. E. Brunner, C. Ingram, A. Meyer and R. Moon.,(4,5) These were: frequent replacement of used soda lime, flushing the soda lime with high flow 02 for one minute prior to each anesthetic and using high fresh gas flow (> 5 I/min). Since implementing these policies no similar cases have occurred at Duke Medical Center.
The guidelines listed above were only intended to be temporary, pending definitive elucidation of the cause. Investigations had begun at Duke Medical Center. While actual cases of CO poisoning were uncommonly discovered, in part because blood gases were measured on only about 10% of patients, 'footprints' of the phenomenon, in the form of measurable gaseous CO within unused anesthesia circuits, were relatively common. On Sunday afternoons dangerously high CO levels (> 1000 ppm) within the soda lime compartments of anesthesia machines were detected in over 2% of measurements (320 observations).
Solutions to the Mystery?
Several hypotheses were investigated, aided significantly by an APSF grant awarded for 1993:
Source Gas Contamination: Because of the sporadic occurrence of the cases, and repeated failure to find high significant CO concentrations, this possibility was unlikely.
Chemical Reaction Between Soda Lime and Anesthetics
Studies dating back to the early 20th century indicate that certain chlorinated halocarbons can indeed generate CO when exposed to strong bases. For example, chloroform (CHC13) undergoes a reaction with sodium hydroxide to produce CO, with formate (CHCOO-) as an intermediate.' In the presence of soda lime trichloroethylene (Trilene: CHC12CH2CI) produces equimolar quantities of phosgene and CO."' (While the phosgene production associated with the use of trichloroethylene in semi-closed circuits, and its clinical toxicity, are well described in the literature, the possibility that CO may have played a role in this syndrome seems to have been overlooked.)
Is it possible that fluorocarbons exposed to soda lime could result in analogous reactions? Studies performed in the 1950s indicated that compounds such as fluoroform (CHF3) could react in an alkaline environment in a manner similar to chloroform but at substantially slower rates." Studies of modem fluorinated anesthetics indicated that toxic concentrations of CO did not occur when exposed to soda lime. This was confirmed by studies of our own, in which Sodasorb was exposed for a prolonged time to saturated vapors of halothane, enflurane, isoflurane and fluoroform. The highest concentrations of CO observed were after exposure of the absorbent to fluoroform (about 27 ppm), though insufficient to have produced the COHB levels observed in the three institutions.
Contamination of Volatile Anesthetics
Analysis of enflurane from the vaporizer used for one of the Duke cases was performed using a high resolution gas chromatography-mass spectrometry system. Fluorinated compounds other than the main anesthetic were detected in part per billion (ppb) concentrations, but well within the manufacturer's specifications for purity. Further analysis revealed no detectable formate.
Endogenous CO Production
A report by Middleton published in 196511 demonstrated high CO levels within the anesthetic circuits in patients anesthetized using low flow. The authors attributed these levels to endogenous production of CO from hemoglobin breakdown. COHB measurements were not reported. Accelerated erythrocyte breakdown (e.g. hemolysis, blood transfusion) causes increased endogenous CO production and it is possible that under certain conditions exhaled CO concentrations could reach toxic levels. In particular, breathing 100% 02 results in displacement of CO from Hb and an acute increase in PCO in the exhaled gas. Studies in normal volunteers breathing from an anesthetic circuit have shown that the CO concentration in the circuit can rise to 100 ppm or more. Of course self-poisoning by one's own endogenously produced CO would be unlikely, though this could provide a mechanism via which adsorption of CO to soda lime, accumulation and then release could occur (see below).
Soda Lime Contamination
Although the soda lime in semi-closed circuits has been implicated in the pathogenesis of " phenomenon, the mechanism is still not understood and is under active investigation. Formulation does not appear to be important, since both Sodasorb and Baralyme have been in use during the cases collected from the three institutions mentioned above. Analysis of fresh and used Sodasorb samples has revealed traces of formate in some used samples, particularly in ones associated with CO poisoning. Since CO can readily be generated from formate, one has to suspect a possible link. Formic acid is endogenously generated and trace quantities in exhaled gas could be trapped in soda lime, providing a source for CO production. However, in our studies formate concentrations in the exhaled vapor of both normal volunteers and anesthetized patients were orders of magnitude lower than required to explain the observed levels in Sodasorb.
Production of formate in soda lime could also occur from other exhaled substances, such as methane, and is under active investigation. Although energetically unlikely, production of formate could conceivably occur from exhaled CO, perhaps catalyzed by trace amounts of heavy metals in soda lime.
Another possibility is that soda lime could act as a nonspecific adsorbent for CO. Adsorption of halothane, isoflurane, enflurane and sevoflurane to soda lime has been measured and is accentuated if the absorbent is dehydrated.
According to measurements in our laboratory, soda lime can also adsorb CO. Since adsorption is usually inversely proportional to temperature, it is possible that adsorption and accumulation of endogenously produced CO could occur, and then be released if the soda lime temperature is raised. The 'Monday morning" phenomenon could be explained by slow diffusion of CO from the interior of granules.
Return to Low Flow?
Although high fresh gas flows appear to have played a part in reducing the likelihood of CO poisoning, the additional cost of anesthetics is substantial. At Duke Medical Center recently, the policy has been changed to remove the restriction on fresh gas flow rate, while continuing to monitor weekend CO levels. If the distribution of CO levels does not indicate greater numbers of machines with dangerous CO concentrations it may be possible to remove this most costly of the three 1990 guidelines
Because of its episodic nature, the elucidation of the cause of this rare but potentially fatal phenomenon has been difficult to establish. Since it has not (as yet) been reproducible in the laboratory, it is likely to be in part due to interaction between soda lime and some component of exhaled gas from patients. Carbon monoxide poisoning cannot be detected using standard anesthesia monitors. The guidelines for prevention, listed in the text, appear to be effective. Treatment of CO poisoning should include removal from the source, administration of 100% 02 and if neurological symptoms or signs exist, hyperbaric oxygen.
Dr. Moon, recipient of a 1993 APSF Research Grant,
is from the Department of Anesthesiology, Duke University Medical Center, Durham, NC
1. Barker SJ, Tremper KK: The effect of carbon monoxide inhalation on pulse oximetry and transcutaneous P02. Anesthesiology 66:677,1987
2. Gonzalez A, Gomez-Arnau J, Pensado A: Carboxyhemoglobin and pulse oximetry. Anesthesiology 73:573, 1990
3. Piantadosi CA. The role of hyperbaric oxygen in carbon monoxide, cyanide and sulfide intoxication. Probl Respir Care 4:215-231,1991
4. Centers for Disease Control. Elevated intraoperative blood carboxyhemoglobin levels in surgical patients Georgia, Illinois and North Carolina. MMWR 40:248-249, 1991
5. "Safety Persists as ASA Meeting Theme." APSF Newsletter 1991;6:42
6. Kemp DS, Vellaccio F. Organic Chemistry. New York: Worth, 1980, p. 1181
7. Carden S. Hazards in the use of the closed-circuit technique for Trilene anaesthesia. Brit Med 1 1:319-320, 1944
8. Hunter AR. Complications of Trilene anaesthesia. Lancet 1:308-309,1944
9. McClelland M. Some toxic effects following Trilene decomposition products. Proc Roy Soc Med 37:526-528, 1944
10. Firth JB, Stuckey RE. Decomposition of Trilene in closed circuit anaesthesia. Lancet 1:814-816,1944
11. Hine J, Dowell AM Jr, Singley JE. Carbon dihalides as intermediates in the basic hydrolysis of haloforms. IV. Relative reactivities of haloforms. JACS 78-.479482,1956
12. Middleton VA, Van Poznak A, Artusio JF, Smith SM.
Carbon monoxide accumulation in closed circle anesthesia systems. Anesthesiology
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Arizona Practice is Model
by Casey D. Blitt, M.D., Carol Kaufer-Bratt, R.N., Joanne Ashby, R.N., and Julien R. Caillet, M.D.
In the fall of 1987, we embarked upon a comprehensive program of Risk Management, Peer Review, Quality Assurance and Education. The primary goals of this program were to (1) ascertain degree of patient satisfaction, (2) optimize risk exposure, and (3) institute comprehensive educational programs. AU of these goals have the potential to positively affect quality of patient care. Secondary goals include, (1) improved record keeping/documentation, (2) modification of practice characteristics, (3) modification of risk of transfer costs, (4) opportunity for meaningful peer review, and (5) facilitation of claims identification and management.
The practice of medicine involved consists of the private practice of the specialty of anesthesiology and encompasses all areas of that specialty practice with the exception of pediatric open heart and transplant surgery. The anesthesia practice is a 26 person anesthesia group, all salaried employees of a single corporation (Old Pueblo Anesthesia, LTD.) practicing anesthesia with a one physician to one patient ratio on a fee for service basis at multiple heath care facilities. AU practitioners are physicians who have completed an approved residency training program in anesthesiology, are licensed to practice medicine in the state of Arizona and (with two exceptions) are either certified by the American Board of Anesthesiology or are in the examination process.
This report describes the implementation of this program and our experience during the first 70 months (September 1987 June 1993) of this risk management program.
Prior to implementation of the program, a physician was designated as the Risk Management Director and a Risk Management Nurse was hired. These two individuals were accorded salaried positions by the corporation and were charged with identifying problems or potential problems, evaluating the nature of the problems, selecting solutions to the problems, implementing the solutions and following up on implementation to evaluate efficacy. A comprehensive reporting system for identifying problems or complications related to the practice of anesthesia as well as determining degree of patient satisfaction was established. This reporting system was categorized and established in advance of implementation of the Risk Management Program (see Table 1).
The Risk Management Nurse and Risk Management Director are responsible for all aspects of the program. All of the practitioners and many other health care professionals are involved. AU patients cared for in the anesthesia practice are contacted either in person, by telephone or by mail to ascertain patient satisfaction and to identify problems or complications that may have been related to their anesthetic care. Additionally, all practitioners are encouraged to report their knowledge of complications, unusual occurrences, etc., whether they are related to their own patients or to an associate's patients. Health care personnel, not in the practice of anesthesiology, are encouraged to report any problems or unusual occurrences. This includes nurses, other physicians, hospital risk management personnel, etc. All problems, complications, unusual occurrences, are documented, evaluated and entered into a computerized data base. When deemed necessary, patients are contacted by the Risk Management Director, Risk Management Nurse or by the anesthesia practitioner who rendered care to obtain more information and help promote patient satisfaction.
The total number of anesthetic encounters during this 70 month period was 81,765. Of these, 60,336 were general anesthetics and 21,429 were classified as regional anesthetics. There were 1,959 perioperative problems reported for an overall incidence of 2.4%. There were 420 problems reported secondary to regional anesthetics for an overall incidence of 2.0%. Complication rates based upon classifications in Table I are described in Table 11. Incidences of specific problems of interest were 94 cases of peripheral nerve injury (0.11%), 25 cases of awareness under general anesthesia (0.04%), and 29 cases of dental injury during general anesthesia (0.05%).
Although there was some initial resistance (primarily by other physicians), the program was very well accepted by patients, health care facility personnel, and the anesthesia practitioners. At various times in the evolution of this program, practice recommendations were made. All recommendations were approved and instituted by the practitioners. Some of these recommendations required assistance and interaction of health care facilities and health care personnel for implementation. During the course of this Risk Management Program, the following recommendations/guidelines have been implemented:
(1) Minimal anesthesia record documentation guidelines/standards.
(2) Avoidance of subarachnoid opioids.
(3) Administration of supplemental oxygen to all patients receiving subarachnoid/epidural anesthesia.
(4) Administration of supplemental oxygen to all patients having received general anesthesia during transport from the operating room to the post anesthetic care unit.
(5) The use of pulse oximeter on all patients in the post anesthetic care unit.
(6) Monitoring of all patients receiving general anesthesia to include end tidal carbon dioxide, pulse oximetry and temperature when indicated.
(7) Prompt consultation and treatment of all dental injuries.
(8) Prompt appropriate consultation for any medical specialty problem.
(9) Standardization of epidural opioid infusions. (10) Chest radiographs after all central vascular access procedures.
(11) Familiarization with a difficult airway management algorithm.
(12) Availability of transtracheal jet ventilization apparatus at all anesthetizing locations.
(13) Prompt recognition of fee problems with adjustment of professional fees when indicated.
(14) Prompt communication with other medical colleagues when a problem or complication is discovered.
(15) Electronic monitoring of obstetrical patients.
(16) Use of a peripheral nerve simulator on all patients who receive multiple doses of non-depolarizing neuromuscular blockers.
(17) Obtaining informed consent (operative permit) for central vascular access procedures.
(18) All vascular access procedures are performed in the preoperative holding area, except in patients who are hospitalized in critical care areas of the hospital.
(19) Documentation of indications for transfusion whether it be autologous or homologous.
(20) Patients sedated to facilitate any procedure must be appropriately monitored regardless of where in the hospital the procedure takes place.
(21) Patients with a greater than normal risk for perioperative neurological problems related to surgery or anesthesia should have the risks explained to them and documented in the medical record.
(22) Patients undergoing procedures associated with anesthesia where the possibility of awareness is greater than usual should be informed of the possibility of perioperative awareness and this should be documented in the medical record.
(23) Patients must be informed if any individual in any educational program will be observing or participating in the care of that patient.
(24) Adequacy of reversal of neuromuscular blockade should be documented in the medical record.
(25) A postoperative epidural pain control information card must be used on all patients who are receiving epidural opioids for postoperative pain management.
(26) This card must be readily available to the anesthesiologist responsible for the acute pain management service.
(27) All patients are assessed for adequacy of ulnar nerve function (motor and sensory) at time of discharge from PACU.
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Table 1: Categorization of Perioperative Anesthesia Related Problems
I DEATHS (within 48 hours of anesthetic)
II NERVOUS SYSTEM INJURY
A. Coma or persistent vegetative state
B. Peripheral nerve injury
C. CVA (Intraoperatively or within 72 hours postoperatively)
III. REGIONAL ANESTHESIA PROBLEMS
A. Post spinal or epidural headache
B. Nerve injury (see JIB)
IV. CARDIOVASCULAR PROBLEM
A. Perioperative MI (within 72 hours of anesthetic)
C. Significant new arrhythmia
D. Cardiac arrest (intraoperatively or in PACU)
E. Significant blood pressure variation F. Volume problems
G. Vascular access related problems (venous or arterial)
V. RESPIRATORY PROBLEMS
A. Difficult airway management
B. Respiratory arrest (intraoperative, PACU, patient care unit)
C. Aspiration, pulmonary edema, respiratory distress syndrome
D. Reintubation required
E. Inadequate reversal of neuromuscular blockade
VI. MISCELLANEOUS PROBLEMS
A. Dental injury
B. Equipment malfunction/incorrect usage
C. Eye injury
D. Adverse medication reaction
E. Patient dissatisfaction
F. Potentially compensable event (medical/ legal action)
Table II: Frequency of Perioperative Anesthesia Related Problems
ABSOLUTE # RATE
Deaths 151 0.18%
Nervous System Injury 111 0.13%
Cardiovascular Problems 384 0.47%
Respiratory Problems 366 0.45%
Miscellaneous Problems 527 0.64%
The most rewarding part of the program has been the educational aspect. Practitioners are required to attend a minimum of nine hours per year of risk management-related educational meetings. During these meetings, various practitioners present their problems or complications. During these educational sessions (known to residents as morbidity/mortality sessions) all practitioners participate and meaningful information is exchanged, ideas are shared and recommendations for avoidance of future problems are made. This " of educational process encourages the practitioner to research the problem and also provides a forum for input from associates in a nonthreatening manner. All cases to be presented are independently reviewed by the Risk Management Director to insure that presented information is factual and accurate. The educational sessions have been readily accepted by the practitioners, and the professional interaction has been very positive and satisfying. A current project in progress involves establishing a post partum unit with greater acuity of care capability so as to better care for complicated parturients in the post delivery period.
No Surprises in Lawsuits
During the period that this program has been in place, there have been six closed claims. None of the claims 'surprised us" since we had previously been aware of the undesirable outcomes. These closed claims are as follows:
(1) Ulnar neuropathy in an elderly male undergoing transurethral resection of the prostate and inguinal hernia repair. The patient received a subarachnoid anesthetic. The anesthesiologist involved was dismissed early in the discovery process after the plaintiff s deposition.
(2) An elderly gentleman (65+ years) with preexisting cardiovascular disease sustained bilateral lower extremity compartment syndrome after a prolonged cancer operation for bladder and prostatic cancer performed in the lithotomy position. Failure to properly monitor and failure to properly position the patient were the allegations against the anesthesiologist. Subsequent to developing the compartment syndrome, the patient had a stormy hospital course and died approximately six months after the initial operation, The case was settled on behalf of two urologists, the anesthesiologist, a general surgeon, and the hospital.
(3) A middle-aged gentleman (40+ years) with renal failure and significant pulmonary disease sustained a tension pneurnothorax during insertion of a hemodialysis catheter via the subclavian route. Allegations against the anesthesiologist were failure to diagnose and treat the complication in a timely fashion. The patient expired within a week after developing the tension pneumothorax which resulted in cardiovascular collapse. The case was settled on behalf of the anesthesiologist.
(4) A trauma patient (60+ years) undergoing open reduction and internal fixation of an acetabular fracture in the lateral position sustained a hemothorax, alleged to be secondary to improper performance of central vascular access technique. Allegations against the anesthesiologist included failure to detect the hemothorax in a timely fashion. The patient died in the immediate perioperative period. The case was settled on behalf of the anesethesiologist.
A Burn and a Fall
(5) An elderly patient (80+ years) sustained a burn in the axially area secondary to utilization of a warm fluid bag as an axillary roll. The patient was an insulin dependent diabetic and this no doubt contributed to the severity of the bum. This case was settled on the behalf of the hospital and anesthesiologist.
(6) A patient fell from an operating table during an orthopedic procedure to repair a hip fracture. The case was settled on behalf of the anesthesiologist, the hospital and the orthopedic surgeon.
During the course of this program, risk transfer costs have decreased from approximately $52,000 per individual to $17,000 per individual for comparable coverage.
While we cannot conclusively prove that quality of care has been improved, we feel that risk exposure has definitely been minimized as a result of this program. We have encountered no instances of unrecognized airway management disasters (esophageal intubation, etc.) as a result of this monitoring policy. Incidentally there have been at least two airway management disasters in our community during the period of this report. The combination of educational activities and peer review has allowed practitioners to change their practice characteristics in a non-threatening manner. Peer pressure and opinions of associates are apparently strong motivating factors.
We are unaware of the existence of similar programs that are operative outside of educational/ residency facilities in the United States. The establishment and continuation of risk management, quality assurance, peer review, and educational activities in the private practice of the medical specialty of anesthesiology may have the potential to improve quality of care as well as to decrease practice costs. We have been able to identify a number of areas not included in our initial categorization list that are apparently of concern to patients. These include sore backs and sore throats secondary to regional anesthesia and endotracheal intubation, respectively. This is dearly an area of concern to the patients. Another area of concern to a large number of patients is perioperative nausea and vomiting. To this end, we have established a nausea and vomiting reduction protocol for patients receiving general anesthesia.
Areas of perceived future importance in risk management and anesthesiology include issues related to patient positioning and transfer, monitoring of patients outside of the operating room environment, undesirable outcomes of central vascular access and poor patient/ physician interaction with unreasonable expectations of outcome.
Dr. Blithe, Dr. Caillet, Ms. Kaufer-Bratt and Ms. Ashby
are associated with Old Pueblo Anesthesia, Tucson, AZ.
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by Erwin Moss, M.D.
Anesthesia personnel usually automatically assume that the medical gases delivered from the wall outlets in the OR are clean, correct, and safe. While crossed-pipeline accidents always receive significant publicity, an under-appreciated patient safety issue concerns possible contamination of these medical gases with substances or materials that could possibly harm anesthesia equipment and, directly or indirectly, the patient breathing these gases.
The original purpose of the APSF Subcommittee on Medical Gas Systems was to make anesthesiologists aware of the design, location, and problems of the life support system with which they work everyday, but which is beyond the walls and out of sight.
Coincidentally, the ECRI, a non-profit health services research agency, formerly the Emergency Care Research Institute, has devoted a special double issue January-February 1994 vol. 23 No. 9 1-2) to medical gas and vacuum systems (MGVS). This publication should be in the library of every anesthesia department since it contains a crash course in what anesthesiologists should know about their MGVS. The address of ECRI is 5200 Butler Pike, Plymouth Meeting, PA 19462-1298.
ECRI correctly identified issues that this committee recognized early in its research. There is a mass of regulations, codes, and standards published by organizations such as the NFPA JCAHO, OSHA, CGA (Compressed Gas Institute), ANSI, AIA (American Institute of Architects), UL, and at least a dozen others. These regulations, standards, and codes address every aspect of the MGVS in hospitals and ambulatory care facilities from design to the concentration of agents used to clean pipes and valves. Why then are there reports of cross connections and contaminated pipes or why are fortunes needed or spent to correct errors in construction and design?
The ECRI, in its article, asked is there "a paper tiger' in all of these published regulations, standards, and codes? It discusses the "Problem in Enforcing Compliance' and 'The Devil is in the Details." Even the JCAHO which updated its MGVS standards this year (APSF Newsletter Winter 93-94, Tom Nagle) "looks for evidence of a properly installed and routinely inspected MGVS only in the form of proper record keeping; it does not look for in-depth adherence to the standard during on site visits even insurers require that a MGVS meet certain tests and have documents pertaining to use and care ... however, enforcement is lax and only documentation is required.' ECRI further states that 'although state and local building and fire codes may also regulate the construction and operation of MGVS and most state or local departments of health require certification of new installation before occupancy permits are issued ... rigorous enforcement of the standard (NFPA) is spotty and depends on the interpretation of 'authorities having jurisdiction' and the 'responsible facility authority.' Those authorities having jurisdiction .usually rely on information from independent inspectors or contractors, who may or may not be fully knowledgeable about the current details of NFPA-99 or even know how to perform complete testing of the MGVS ... notably in the United States, no nationally recognized agency certifies MGVS inspectors as competent."
The article by ECRI confirms in no uncertain terms what the Committee on Medical Gas Systems of the APSF early identified and that is a lack of an accountable authority to coordinate and enforce the many codes and standards now in place. There should be an organizational chart with a specific agency at the top!
Included in the structure should be the education and credentialing of those involved in MGVS construction from design architects to plumbers. ECRI identified two private organizations involved in training of installers and verifiers, PIPE (Piping Industry Progress and Education Trust Fund, Los Angeles, California and Medical Gas Management, Bethany, Oklahoma). Mr. Fred Evans, President of MGM is a member of the APSF committee on Medical Gas Systems. Another organization cooperating with this committee is the American Medical Gas Institute, a nonprofit organization, located in Metairie, Louisiana. There is a common frustration expressed by these companies in that they deal daily with the problems of faulty design, construction, installation, inspection, and certification, only to have deaf ears turned to them when recommendations to correct the faults to meet NFPA-99 standards are made to administrators.
California has strong MGVS construction requirements resulting from the Sylmar Earthquake of 1971. ECRI explains that 'state law demands that MGVS adhere to the requirements of NFPA-99 as well as other codes defined by such agencies as AWS, CGA, ANSI, OSHA, and UL. Contractors must be certified as competent by recognized agencies such as AWS (American Welding Society), PIPE and ACIA (American Construction Inspection Association).
Inspect the Inspectors!
It is important that anesthesiologists understand that new construction may be inspected and certified by an individual who may not have himself or herself been credentialed for the task. It is not unusual for a facility to request certification just before opening its doors. Construction has been finished, the walls erected and the verifier (certifier) is limited to what he can see and do! Hidden behind the wall may be errors in design, incorrectly joined pipes which are improperly hung or supported and unclean. It is important not only to identify the gas flowing from each outlet, but to have an analysis of purity including particulate, chemical, and bacterial contamination. Logically, inspection of the MGVS should be continuously performed during each step of construction by credentialed inspectors and before the walls are put up. Certification should be by a disinterested third party as is required by Canadian Standards. It is not unusual for the contractor to be the certifier of his own work. Tennessee, through efforts of Mr. Fred Evans and Mr. Pete Winbourne, retired from Ohmeda, is in the process of requiring third party certification and MGVS regulations much like California has. Interestingly, Armed Forces facilities require certification by a third party.
Again, anesthesiologists must involve themselves during the construction phase of their MGVS. They must be knowledgeable as to the NFPA-99 codes. An excellent reference is the 'Health Care Facilities Handbook' Fourth Edition published by the NFPA in which each code is explained in easy to understand terminology. Anesthesiologists should not hesitate to don a hard-hat and enter the construction area. They are the end users of the MGVS and should understand the complexity of this life support system of their hospitals.
Anesthesiologists, during their workday, turn on gases and the vacuum systems with little thought as to the purity of the gases or the complexity of the MGVS. At the same time, in other units of the facility, gases are flowing to infants in incubators or on ventilators, or to patients in the ICU, CCU and even the Emergency Room. Suction is in use in all parts of the hospital. Although deaths are rare compared to the total number of patients using MGVS, when they do occur, the event gains nationwide attention and is followed by awards in the millions. In a ten year period one company, Medical Gas Services of Lenexa, Kansas, reported 205 instances of cross connection of which 81 involved a cross connection of a gas to the vacuum system. The excellent Canadian Standard is a result of 23 deaths in Sudbury, Ontario, in 1973 due to errors in construction of the MGVS.
California, according to PIPE, had as of December 1993, 368 certified inspectors and 22 certified verifiers as compared to many states that have none of either. California also hired an engineer to evaluate MGVS plans while in other states, approval of plans may be based on what the contractor tells the state.
Although there may be other organizations teaching and certifying installers, inspectors, and verifiers, the number is small. PIPE and MGM have training centers as well as the American Medical Gas Institute.
All three organizations offer programs in all parts of the United States. Although performing a vital service, they admit that they have developed their own curriculum and certification criteria and that there is no supreme body that sets educational standards as exists in our medical education system.
The worse possible scenario, other than crossed pipe lines, is an error by the manufacturer in the filling of tanks with the wrong gases at the manufacturing site. This possibility is responsible for the recommendation of the constant use of an oxygen analyzer on the machine even though an oximeter is in use. An oxygen monitor would have alarmed when a cylinder filled with nitrogen in error instead of oxygen was put on he. However, these monitors are not routinely used in other parts of the hospital. Therefore, it is important to understand the regulations placed on the manufacturer of the gas supply who incidentally are responsible for maintaining the bulk gas supply at hospitals.
When gas outlets are certified, the concentration or purity of the oxygen, nitrous oxide, nitrogen, or medical air is documented. What is not routinely identified is contaminants that may be present in acceptable or unacceptable levels. Particulate, foreign bodies, and bacteria are not the usual part of a certification of medical gases.
Included in the list of contaminants are metal fillings, flux, teflon, carbon, carbon oxide, oil and its breakdown products, halogenated solvents, methane, carbon monoxide, nitrogen oxide, hydrogen fluoride, hydrogen sulfate, carbon dioxide, cement, dirt, vermin, copper, copper oxide, copper carbonate, iron oxide, sand grains, wood chips, sodium crystals, chlorine, halogenated refrigerants, desiccant dust, fibers, aldehyde, lint, water and odor.
CO Monitored But Odor Banned
While there is an acceptable level for carbon monoxide (5PPM), and as of 1993 there must be a carbon monoxide monitor on the medical air system, there is no acceptable level for odor. Any odor originating from a medical gas system must be traced to its source. It is often the result of bacterial contamination or oil in the system. The medical air system, because of moisture, is the most common site of bacterial contamination. However, bacteria can grow in spaces left in improperly joined pipes. Culturing of medical gas is rarely performed. While ventilators and respiratory care systems are a known source of infection due to bacterial contamination, the idea that the source could be beyond the
walls in the pipe systems is not easily accepted by owners or administrators possibly due to liability issues and the need to clean the systems once the contamination is identified.
Water that accumulates in medical air as a result of malfunctioning dryers can come out of air as dewpoint changes occur along the pipeline course. A dewpoint monitor and alarm is a part of a properly designed medical gas system. Remember, medical air is the result of compression of eight cubic feet of atmospheric air into one cubic foot of compressed air and that all contaminants in atmospheric air, including water and carbon monoxide, are therefore concentrated eight fold in compressed air.
The presence of iron or iron oxide (rust) is evidence of iron pipe being used against NFPA code somewhere in the MGVS. Once iron is documented after a nitrogen purge of a MGVS, a search should be made for the iron pipe. The iron pipe should then be removed and replaced by copper to meet the NRA code requirements.
Documented contamination of pipelines includes dirt, sand, gravel, cement, rust, vermin, cigarette butts, and wood. This form of contamination results from the pipes and bulk gas containers being opened and exposed to construction debris and to the atmosphere. NFPA code now requires all pipes to be clean and capped at the factory. The bulk gas system is delivered and installed by the gas supplier and may be on the construction site with ports open to the atmosphere. The anesthesiologist would be wise to check the bulk oxygen site and the condition of the containers during construction. The largest particulate recently found was a bird that had been sucked into a medical gas system as a result of faulty construction of the medical gas pipeline. Chemical contamination can be the result of solvents used by the manufacturer to clean pipes and valves.
The major form of particulate matter contamination is the result of improper joining (brazing) of pipes and joints during construction. Brazing should be performed by a certified brazer, but in reality may be performed by a plumber unaware of NFPA code that requires brazing be performed with the interior, pipe purged with oil free nitrogen. When brazing is carried out in room air within the pipe, the oxygen content of the air can cause oxidation of the pipe at the temperatures required for brazing. The result is carbon, copper oxide, and carbon oxide.
Later, copper carbonate, recognized by its green color, is formed. AU contaminants can scale off the interior of the pipe, flow downstream and impair the function of equipment such as flowmeters, outlets, ventilators, and blenders in ventilators.
The brazing must be carried out at 1000 degrees F using a special joiner specified by NFPA-99 code. Nitrogen purging must continue until the pipe is cooled to touch, otherwise oxidation will occur. This relatively simple procedure, first put into code in 1993, can prevent the major share of particulate contamination in MGVS. Yet, new construction completed in 1994 has found particulate contamination not meeting NFPA-99 standards. Although the NFPA-99 describes the brazing technique, the contractor may have given the job to a low bid plumber who is not acquainted with the code.
Examination of a pipe system for particulate matter involves a white cloth being placed over an outlet permitting gases to flow through the cloth. The cloth acts as a filter. The color, amount, and size of the particulate matter will determine the degree of contamination while identification of the particles and size can be made by microscopic examination.
Cleaning of a pipe system can be performed by purging with nitrogen or washing. Purging will blow out loose scale and is temporary while washing with an acid solution can be a permanent solution, but is expensive and complex in that washing is performed zone by zone with shut down of zones during the process or may require the complete shutdown of the medical gas system.
Once again, the anesthesiologist should involve himself or herself in any new construction or addition to present systems. The credentials of the designers, contractors, installers and certification expert should be verified. Even the brazer should be credentialed.
Inspection should occur during the various phases of construction. Certification should be by a credentialed expert. Pipe lines should not only be certified for gas identification, but for contamination. It is hoped that more can be learned about bacterial contamination and its prevention and treatment.
In future articles the following topics will be discussed:
1. Gas shutdown of hospitals during construction or enlargement of the gas systems in a facility.
2. The problems and responsibility of bulk gas supply.
3. The medical air system.
4. Recent updates in NFPA code.
5. Important points to watch for, as an anesthesiologist, in design, construction, inspection, and verification of a medical gas system.
Dr. Moss of Verona, NJ, has been very active with and
is a consultant to the New Jersey State Society of Anesthesiologists.
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Floor Hoses Are Another Gas Source Hazard
To the Editor
I read with interest the article in the recent APSF Newsletter titled 'New Standards Focus on Piped Medical Gas Systems.' While it is generally true that the medical gas distribution system '...typically does not receive as much attention' from the anesthesiologist, I would like to point out a common scenario.
I have been a practicing anesthesiologist for 17 years. For most of my professional life, I was unable to easily move my anesthesia machine to accommodate the varied surgical procedures performed in each operating room. Cords or hoses jammed under the castered wheels of the anesthesia machine often immobilized my machine. Occasionally this caused .seconds of terror" when I couldn't ... quite reach
More than once I have manhandled the machine over oxygen hoses or electrical cords in order to connect a breathing circuit to an apneic patient. It is possible to damage a high pressure gas hose or an electrical cable in this manner and create a fire or environmental hazard in the operating room, as well as to jeopardize oxygen and/or anesthetic delivery to the patient.(1)
Ceiling mounted towers and suspension mechanisms require major physical and financial investments. Tying the cords behind the anesthesia machine limits our ability to follow a patient on his or her way to the surgeon. Neither the anesthesia machine nor the caster manufacturers have a satisfactory solution to this problem. I have designed, patented and am using my own solution which I believe would be of interest to you and to the readership of the APSF Newsletter.
The obstacle clearing device that I have developed rests upon the floor, is assembled around an existing wheel but is not attached to it and serves no weight-bearing function. It moves with the caster and pushes ahead of it the items which an unprotected wheel would otherwise come in contact with. It contributes significantly to the safety of our patients and our co-workers by minimizing the damage inflicted by the casters of anesthesia machines upon ground-based electrical cords and high-pressure gas hoses.(2)
Mr. Nagle's article in your newsletter points out the need for anesthesiologists to become involved in assuring a properly operating piped medical gas distribution system. The JCAHUs booklet 'Using the 1994 Joint Commission Accreditation Manual for Hospitals' for Chiefs of Anesthesia stresses that 'Anesthesia's extensive use of gases, monitors and other technologies makes equipment management especially relevant.' I feel that this obstacle clearing device allows an anesthesia department to more closely comply with the National Fire Protection Agency's requirements (3) and serves as evidence of positive involvement in a continuous quality improvement process.
John J. Navar, M.D. Corpus Christi, TX
1. Anderson, WR and Brock-Utne, JG: Oxygen pipeline supply failure: a coping strategy, FFA(SA). J. Clin Monit 1991;7(l):3941.
2. Lacoumenta, S and Hall, GM: A burst oxygen pipeline (letter). 'Anaesthesia' Jun 19830:596-597.
3. National Fire Protection Agency. National Electrical Code 70-10 (110-17); 70-57 (3004); 70E-31(chapt 3,F(l).
FDA Negative Pressure Test Seen Impractical In Japan with Certain Vaporizers Installed
To the Editor
According to the proposed FDA checklist (APSF Newsletter, Winter 1992-1993: 47-51, 1992), it is advisable to use the negative pressure leak test with a suction bulb in order to maintain the safety and the reliability of the anesthetic machine.
Recently, we found this test to be impracticable in some anesthetic machines. It was found to be caused by the installed vaporizers in some of the machines, which are not designed to withstand a negative pressure. These vaporizers are the Tec 3 (Ohmeda Co., Ltd.) and the Acoma F-MKIII (Acoma Co., Ltd.), so far as we have investigated.
Concerning the leak check of machine low pressure system, ISO 5358 (anesthetic machines for use with humans) and JIS T 7201 (anesthetic machine) describe that the maximum leakage shall be 50 ml/min at pressure of 3kPa. However, this check needs the specific flowmeter and is time consuming to perform. Compared with this method, the negative pressure leak test is simple and easy to do, but it should be stressed that this test may be impracticable with some machines.
Satoshi Watanabe, M.D, Professor, Department of Clinical Engineering, Kitasato University School of Allied Health Sciences.
Kaoru Kobayashi, Clinical Engineering Technologist, Medical Engineering Center, Kitasato University East Hospital, Sagamihara, Kanagawa, Japan
Italy, Japan Publish Anesthesia Monitoring Protocols
Italian Society "Recommends'
To the Editor
Because of the growing consensus among anaesthetists that considerable improvements in patient safety can be effected by the adoption of better monitoring standards, the Committee for Safety in Anaesthesia of the Italian Society of Anaesthesia, Analgesia, Rianimation and Intensive Care (S.I.A.A.R.T.I.) has published 'Recommendations for standards of monitoring in Anaesthesia,' which are reprinted below for the interest of our colleagues in other countries working on the same issues.
Prof. G. Torri and Ida Salvo Milan, Italy
Recommended Anaesthesia Equipment for General Anaesthesia in Italy:
ECC monitor and recorder, HR
BP, non invasive
arterial BP, invasive
1. PATIENT VIGILANCE DURING GENERAL ANAESTHESIA
1.1 Continuous vigilance
General anaesthesia, local-regional anaesthesia and sedations involving risk of unconsciousness which may be required also out of the operating theatre must be performed by a registered attending anaesthetist which in Italy is a specialized anaesthetist controlling anaesthesia and vital signs of the patient throughout the entire conduct of anaesthesia and sedation.
1.2 Remote control
An exception is made when there is a direct known hazard (e.g., radiation) to the anaesthetist. In these cases an adequate provision for remote observation and monitoring of the patient must be made.
1.3 Relief of the anaesthetist.
The anaesthetist that starts a procedure normally ends it. When this is not possible and patients have to be handed over to another anaesthetist, the last should be made aware of the relevant information concerning the conduct of anaesthesia and the use of the equipment.
The patient's vital signs and the time of the "hand-over" should be documented on the anaesthesia chart.
2. CONTROL OF TECHNICAL AND PHARMACOLOGICAL DEVICES
Before starting anaesthesia the anaesthetist should carefully check on the functioning of the anaesthesia machine, medical gas supply lines, drugs and immediate life support devices for emergency circumstances.
3. CLINICAL OBSERVATION AND MONITORING DEVICES FOR GAS EXCHANGES
3.1 An analyzer for continuous measurement of oxygen delivery with audible and visual high-low oxygen alarms is highly recommended on all anaesthesia circuits.
3.2 An adequate lightening of the operating theatre is required. Whenever possible this observation should be supplemented by pulse oximetry measuring continuous oxygen saturation.
During mechanical ventilation, in addition to clinical observation, the patient's respiratory function must be monitored with one of the following devices:
a) a disconnection alarm
b) a spirometer with audible and visual high-low alarms set in the expiratory line
c) a capnometer monitoring end-tidal carbon dioxide
5.CARDIOVASCULAR CLINICAL CONTROL AND MONITORING DEVICES
5.1 For all patients undergoing general anaesthesia an ECG with heart rate and alarms continuously displayed from induction until leaving the operating theatre is highly recommended.
6. TEMPERATURE CONTROL
6.1 Normothermic conditions must be preserved. During every general anaesthesia, besides clinical evaluation, there should be readily available a mean to measure the patients temperature continuously.
7. All data provided by mechanical, electronical and clinical monitoring should be carefully reported on the anaesthesia chart.
8. All devices must meet CEN and ISO requirements and assure electrical safety (IEC 601.1; CEI 62.5).
Readers Comment on Sedation Signs
To the Editor
Anyone who has used Versed for sedation is certain to recognize the 'poof' Dr. Karen Shea refers to in her letter, 'Is Patient Adequately Sedated?,' in the Spring 1994 APSF Newsletter.
1 regret to inform her, however, that for the past several years this sign has been referred to as "Versed lips" by me and my colleagues. I believe "Versed lips" describes this sign of adequate sedation much more clearly than another new eponym.
Michael A. Less, M.D. Elmhurst, IL
Whiff Added to "Poof"
To the Editor
I wish to comment on the letter of Karen Shea, M.D., regarding clinically recognizing adequate patient sedation.
I enthusiastically endorse her bid for immortality by describing the phenomenon of a well sedated patient's lips going 'poof.' I have used this clinical finding for years, but never knew what to call it. One of my own refinements at times is to administer small amounts of anesthetic gasses until the poofing occurs. Not wanting to detract from widespread recognition of the 'Shea Sign,' I propose that my described use of it be known as the "whiff 'n poof" technique.
John Mumma, M.D. Medical Director
Bellingham Surgery Center, Inc. Bellingham, WA
Big Chill Tests Blocks
To the Editor.
Having recently passed a major milestone, this "older" anesthesiologist would like to share her personal method of safely testing adequacy of regional anesthetic blocks when the patient is adequately sedated ("poofed"?). (1)
The electrocautery grounding (Bovie) pad that feels like the Arctic tundra when initially placed upon the unanesthetized patient's skin is but a "gooey' sensation to the lucky patient under conduction anesthesia. The patient is spared the frightening sight and sting(!) of a sharp needle to "check the level of the block." The anesthesiologist doesn't create unsightly and unhealthy bloody needletracks on the patient's body. The nurse, instead of running for ice chips for the anesthesiologist to check the level of anesthesia, concentrates on prepping the patient so the ever-impatient surgeon can cut. No time is wasted.
One word of caution remains. The Bovie pad must be placed initially on the anesthetized side. Otherwise even the most comfortably sedated patient under the best unilateral conduction block will complain of a painfully intense cold sensation.
I hope this practice pointer proves that neither old age nor treachery is necessary to deliver safe and effective regional anesthetics!(2)
Wendy B. Kang, M.D., J.D.
Assistant Professor, Department of Anesthesiology The university of Texas
Southwestern Medical Center at Dallas, TX References
1. Shea, K: Is patient adequately sedated? (letter). APSF Newsletter Spring 1994; 9:12.
2. Lm, DE: Are 'older' anesthesiologists necessarily incompetent,
as says "callow youth?' (letter). Ibid.
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To maintain and encourage the safety of the patient undergoing anesthetic care, the Japan Society of Anesthesiology (JSA) has adopted the following minimal guidelines that apply for the administration of general, epidural and spinal anesthesia:
Guidelines for Minimal Monitoring.
1. The physician in charge of each anesthetic shall always be present to watch the patient continuously to provide appropriate anesthesia care.
2. Monitoring by pulse oximetry shall be employed. To ensure adequate oxygenation of the patient, the patient's skin, mucous membranes and blood color shall be assessed.
3. To ensure adequate ventilation of the patient, clinical signs such as observation of chest excursions, observation of the reservoir breathing bag and auscultation of breath sounds shall be assessed. Monitoring end-tidal C02 with capnographic waveform is highly recommended; and monitoring of expired gas volumes is recommended when it is clinically indicated.
4. To ensure adequacy of the patient's circulatory function, every patient should be evaluated by at least one of the following: auscultation of heart sounds, palpation of arterial pulses, monitoring of intra-arterial pressure tracing or pulse plethysmography. Every patient shall have the electrocardiogram continuously displayed, and their blood pressure and heart rate shall be measured and evaluated at least every 5 minutes. Where it is clinically indicated, invasive arterial blood pressure monitoring should be available to those patients indicated.
5. To control the patient s temperature appropriately, the patient's temperature shall be continuously monitored.
6. Adequacy of muscle relaxation shall be monitored when it is clinically indicated.
Note: The anesthesia machine and equipment shall be tested
according to the anesthetic apparatus pre-operative check-list and maintenance
manual previously established by the Japan Society of Anesthesiology (1990).
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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 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, 1994
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; 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. Eichhorn, M.D., Editor, David E. Lees, M.D. and Gerald L. Zeitlin, M.D., Associate Editors; Stanley J. 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.
Address all general, membership, and subscription correspondence to:
Anesthesia Patient Safety Foundation
c/o Mercy Hospital
1400 Locust Street
Pittsburgh, PA 15219
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
2500 North State Street Jackson, MS 392164505
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