Volume 9, No. 3,25-36 Fall 1994
Table of Contents
Source of Toxic CO Explained: -CHF2 Anesthetic + Dry Absorbent
UCSF Research Shows CO Comes from C02 Absorbent
FDA Group Urges Sux Label Wording Reduced to 'Warning'
126 Papers, Lectures at ASA Highlight Safety
Editorial: Sux Debate Shows Process of Drug Education
Shutdown of Gas Supply System Need Not Be Danger
Letters to the Editor
FDA Publishes Final Version of Revised Apparatus Checkout
APSF Grand Patrons Recognized

Source of Toxic CO Explained: -CHF2 Anesthetic + Dry Absorbent

Drug Name Policy Detailed, Origin of CO Unveiled Here

Editor's Note: In the Summer issue of the Newsletter, there were both a case report of apparent CO toxicity involving the interaction of volatile anesthetics and carbon dioxide absorbent in a circle breathing system and an explanatory discussion of this phenomenon. In the original typescript versions of both articles, reference was made to the anesthetic Suprane (desflurane) by the authors as part of the case report.

In keeping with the Newsletter editorial policy that has existed since the Newsletter was founded in 1986, reference to any specific brand-name product was deleted. It has been and will be policy to avoid as much as possible any content that could be interpreted as either endorsement of or warning about any specific brand-name product, as that is not the intended purpose of the Newsletter or the Foundation.

Further discussion and understanding of the reported observations appear for the first time anywhere in this issue of the Newsletter. E.I. Eger, M.D., a recognized investigator of halogenated volatile anesthetics and a consultant to Ohmeda, refers in the beginning of the article to "a potential hazard that attends the administration of modern halogenated volatile anesthetics, including the newest of these, desflurane." Because of the unusual opportunity to present the first public announcement of important new findings with significant patient safety implications and, also, for clarity, an exception to the general Newsletter editorial policy is now being made in " case.

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UCSF Research Shows CO Comes from C02 Absorbent

by Z. X. Fang, M.D., and E. L Eger, II, M.D.

Unraveling of the reported unexplained appearance of carbon monoxide during general anesthesia, which is presumably related to an interaction of a potent volatile anesthetic and the carbon dioxide absorbent, has begun through a series of experiments at the University of California, San Francisco (UCSF) and is revealed here for the first time.

Two articles in the APSF Newsletter (Summer, 1994) indicate that carbon monoxide toxicity represents a potential hazard of the administration of modem halogenated volatile anesthetics, including the newest of these, desflurane.(1,2) Headlines of these reports suggest that the bases for such toxicity and the relationship to the choice of anesthetic or absorbent are unclear. Questions have been raised. Why are the reports of measurable levels of carbon monoxide rare? Why do the cases appear to occur in patients anesthetized on Monday or after a period of non-use of the anesthetic equipment for two days? Why does the development of carbon monoxide not consistently correlate with the duration of use of absorbent? (3) Why have most of the past reports been associated with enflurane, with a new report associated with desflurane?

Results from preliminary studies conducted at UCSF supply answers to these questions. The results suggest guidelines that should prevent the production of carbon monoxide. Although no report has indicated that patient harm has resulted from the production of carbon monoxide during general anesthesia, avoidance of such a risk would seem prudent and in the best interest of patient safety.

Methods and Materials

We used standard commercially-available soda lime (Sodasorb) and Baralyme, and also soda lime and Baralyme we dried to various degrees for purposes of the experiments. We directed a flow of 12.5 mL/min of desflurane, enflurane, halothane, isoflurane, and sevoflurane, each at a concentration of what would be approximately 0.8-1.0 MAC or approximately 2 MAC, through tubes containing 21-25 g of these absorbents. The tubes (in duplicate for each determination) were placed in a water bath to control temperature. Using gas chromatography, we measured any carbon monoxide issuing from tubes (limits of detection approximately 1-10 ppm). The chromatograph employed a molecular sieve and a thermal conductivity detector. Similarly, using flame ionization detection and a column containing 10%/SF96 on Chromosorb WHP, we determined the inflow and outflow concentrations of the volatile anesthetic.


Degradation of Anesthetics by Standard Absorbents: No appreciable production of carbon monoxide resulted from the action of standard (with normal moisture content referred to as "wet") absorbents on any of the anesthetics at temperatures of up to 45'C, although sevoflurane (but not other volatile anesthetics) degraded in the presence of both absorbents. Standard (wet) carbon dioxide absorbent granules contain 13% water (in Baralyme) to 15% water (in soda lime).

Effect of Temperature and Anesthetic on Carbon Monoxide Production from Dry and Partially Dry Absorbents: In contrast to the effect of standard (Wet) absorbents, completely dry (no water) soda lime and Baralyme and partially dry soda lime and Baralyme produced carbon monoxide when exposed to all the volatile anesthetics, and did so to higher and/or more prolonged peak levels as the temperature of the reaction was increased. Although carbon monoxide resulted from exposure to all the anesthetics, the amounts produced with halothane and sevoflurane were small. In contrast, substantial amounts could be produced with all three anesthetics containing the CHF2 Moiety. Among these three anesthetics, the highest peak level of carbon monoxide was produced with desflurane, followed next by enflurane and then by isoflurane.

For example:

Dry Baralyme at 45'C produced still higher peak levels:

These peak levels were not sustained, progressively decreasing with continuing flow of anesthetic through absorbent. Thus, after 4 hours (240 min) of flow through dry Baralyme, the respective values with dry Baralyme were 2,070 ppm, 1,050 ppm, and 1,250 ppm.

Partial wetting of the absorbents (retention of some water but still not the normal amount) dramatically decreased production of carbon monoxide. For example, soda lime containing 1.4% water (i.e., one-tenth the normal water content) at 45'C produced much lower peak levels than dry soda lime: 5.0% desflurane 230 ppm; 1.2% enflurane 230 ppm; and 1.0% isoflurane 110 ppm. With soda lime, at a 4.8% water content, no carbon monoxide was produced. Achieving a similar effect with Baralyme required more wetting. Baralyme containing 1.6% water still produced high peak levels of carbon monoxide at 45'C (4.0% desflurane 14,800 ppm, 1.2% enflurane 4,400 ppm; and 1.0% isoflurane 980 ppm), but Baralyme containing 4.7% water produced levels roughly equivalent to those produced by soda lime containing 1.4% water. With Baralyme containing 9.5% water (still less than the normal fraction), no carbon monoxide was produced by the interaction of Baralyme and the volatile anesthetics. As with completely dry absorbent, peak levels were not sustained. For example, after 240 min of flow through Baralyme containing 1.6% water, the levels were: desflurane 1,500 ppm, enflurane -1,400 ppm; and isoflurane 1,000 ppm.

The above data for peak carbon monoxide levels exaggerate both the sense of the dose of carbon monoxide delivered and the apparent differences among the three anesthetics. The exaggeration of the impact of the dose results because of the rapid decay from the peak and because higher peak levels also were associated with an even more rapid decay in carbon monoxide production. For example, the above-noted peak values for 1.6% water in Baralyme differ by a factor of 15 (desflurane giving a value 15 times greater than that for isoflurane). However, the average values for a four-hour period of delivery differ by a factor of 5 (desflurane 4,700 ppm, enflurane 3,400 ppm, and isoflurane 900 ppm).

Relationship of Anesthetic Degradation to Carbon Monoxide Production from Desflurane, Enflurane and Isoflurane: The peak levels of production of carbon monoxide coincided with the total or near-total destruction of each anesthetic by a chemical reaction involving the absorbent. However, it appears that many chemical pathways of destruction are involved because although complete destruction of the volatile anesthetic might continue, the production of carbon monoxide nevertheless would wane. The increasing emergence of anesthetic in the stream issuing from the absorbent correlated with decreasing emission of carbon monoxide.

Effect of Anesthetic Concentration on the Concentration of Carbon Monoxide Produced: Increasing the concentration of anesthetic directed through absorbent nearly proportionately increased the peak levels of carbon monoxide reached. The areas under the curves did not differ as much as the peak heights because the higher peak levels were not sustained.


Although our artificial system will not necessarily reflect absolute concentrations of carbon monoxide that might be produced from these anesthetics being used in a conventional anesthesia machine/ gas delivery system, we believe it will reflect the relative production resulting from the changes in the factors examined (e.g., dryness, temperature, anesthetic type and concentration). We have chosen to examine clinically-relevant concentrations of presently available anesthetics and clinically relevant temperatures. The higher temperatures chosen are those that can be obtained in dosed circuit anesthesia.' Although dry soda lime and Baralyme are not commonly used, these normally 'wet' absorbents (normal water content) may become dry if higher flow rates are applied or if the inflow of oxygen is continued overnight or over a weekend. (4) Thus, although the absolute levels of carbon monoxide developed in these systems will not be replicated in clinical practice, they indicate relative levels that might be anticipated.

We find that temperature, dryness of absorbent, type of absorbent, choice of anesthetic, and anesthetic concentration each can influence the concentration of carbon monoxide that can result from chemical degradation of the anesthetic by the absorbent. An increase in temperature and absorbent dryness increases anesthetic degradation and resultant production of carbon monoxide. However, of these two factors, dryness is, by far, more important than temperature. Baralyme produces more carbon monoxide than soda lime, particularly with a very (abnormally) low water content. More carbon monoxide is produced from desflurane and enflurane than from isoflurane and, for practical purposes, Do carbon monoxide is produced from halothane or sevoflurane.

Explains Case Reports

Our results can explain the anecdotal reports of appreciable levels of carbon monoxide appearance, in some cases enough to cause toxicity. The rarity of the reports is explained by our finding that production of appreciable levels of carbon monoxide requires nearly complete drying out of the absorbent. Such drying is rare, or at least unusual. The finding that higher levels usually appear in the first cases anesthetized on a Monday (5) may be explained by drying of absorbent over the weekend, which would be particularly Rely if oxygen flow through the absorbent has been unintentionally continued all weekend. 100% oxygen flow at the end of a case in order to assure adequate oxygenation before moving the patient to the post anesthesia care unit is common. If left on after the last case on Friday, this completely dry gas would be directed through the top end of the absorbent (6,7) (the freshest portion) and, with the prolonged period of a weekend, would dry the absorbent. The present study shows that more carbon monoxide is likely to be produced from such dry absorbent. Similarly, the finding that carbon monoxide levels roughly correlate with the length of time that an absorbent canister is in place could be explained by drying of the absorbent by the use of high inflow rates. Variation in inflow rates applied could explain the limited nature of the correlation found (i.e., could explain the variability of the results).

The report by Lentz found carbon monoxide in a patient given desflurane on Monday morning using a machine in which Baralyme was the absorbent.' The hospital involved subsequently discontinued the use of Baralyme, substituting soda lime (unpublished report). Although desflurane continues to be used at this hospital, no subsequent cases of significant levels of carbon monoxide have arisen. The findings reported here would explain this occurrence. Baralyme causes a greater conversion of anesthetic to carbon monoxide than does soda lime, particularly if these absorbents contain abnormally low levels of water. Finally, most previous reports implicated enflurane, and a recent report has implicated desflurane, a finding consistent with our data indicating that absorbents acting on these agents produce higher levels of carbon monoxide than those resulting from degradation of the other volatile anesthetics.


The findings reported here lead to specific recommendations for the avoidance of carbon monoxide production from the interaction of potent volatile anesthetics with carbon dioxide absorbent:

1. Ensure the use of standard absorbents containing the full complement of water. Use of relatively low fresh gas inflow rates for the majority of procedures should provide a sustained level of water content in the absorbent to avoid carbon monoxide production.

2. A corollary to (1) is to discontinue the use of high inflow rates when they are no longer needed (e.g. after equilibration of the patient to the desired maintenance level of volatile anesthetic). If an inflow of dry gas has been accidentally continued over a weekend, replace the absorbent with fresh absorbent. Data regarding the potential impact in this context of a continued flow of gas over one night are not yet available.

3. The use of soda lime rather than Baralyme should decrease the likelihood of production of appreciable amounts of carbon monoxide both because Baralyme that is completely dry produces more carbon monoxide, and because preservation of some of the water content (partial wetting) of soda lime reduces production of carbon monoxide more than the partial wetting of Baralyme.

These data and additional details are being submitted in a formal manuscript to a peer-reviewed anesthesia journal with the intention of the earliest possible publication.

Dr. Fang is a Research Fellow and Dr. Eger is Professor in the Department of Anesthesia, University of California, San Francisco, CA. Dr. Eger is also a consultant for Ohmeda.

This research was supported by grants from Ohmeda, Pharmaceutical Products Div., Inc., and from The Anesthesia Research Foundation.


1. Lentz R: CO poisoning during anesthesia poses puzzles. Anesthesia Patient Safety Foundation Newsletter 1994; 9:13-14.

2. Moon R: Cause of CO poisoning, relation to halogenated agents still not clear. Anesthesia Patient Safety Foundation Newsletter 1994; 9:13-16.

3. Moon R, Ingram C, Brunner E, Meyer A: Spontaneous generation of carbon monoxide within anesthetic circuits. Anesthesiology 1991; 75:A873 (Abstract).

4. Strum D, Eger El 11: The degradation, absorption, and solubility of volatile anesthetics in soda lime depend on water content. Anesthe Analg 1994; 78:30348.

5. Moon R, Meyer A, Scott D, Fox E, Millington D, Norwood D: Intraoperative carbon monoxide toxicity. Anesthesiology 1990; 73:A1049 (Abstract).

6. Harper M, Eger El U: A comparison of the efficiency of three anesthesia circle systems. Anesth Analg 1976; 55:724-729.

7. Eger El 11, Ethans C: The effects of inflow, overflow and valve placement on economy of the circle system. Anesthesiology 1968; 29:93-100.

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FDA Group Urges Sux Label Wording Reduced to 'Warning'

by Robert C. Morell, M.D.

Adoption of a drug label statement that succinylcholine is contraindicated in pediatric patients provoked a great deal of discussion, including in an extensive debate and editorial in the Spring 1994 APSF Newsletter. Subsequent events have led to a strong recommendation that this contraindication be downgraded to a warning. Outlined here is the chronology of the involved events, revealing to the anesthesiology community for the first time the process by which drug labeling, particularly involving perceived hazards, occurs.

The Issue

The elective use of succinylcholine in children and adolescents has been a topic of intense controversy during the last two years. Corporate, academic, and federal representatives have debated the relative risks and benefits in the anesthesia literature and in the governmental regulatory arena. A great deal of 'grass roots' testimony by practicing anesthesiologists from all areas of the country has also been submitted to the U.S. Food and Drug Administration (FDA). The primary issue at the center of the debate is the potential ability of succinylcholine to precipitate an acute hyperkalemic cardiac arrest in children with undiagnosed myopathies (usually Duchenne's muscular dystrophy). The debate would not exist except for the fact that many anesthesiologists believe that no other drug possesses the same pharmacokinetic and pharmacodynamics characteristics, or allows intramuscular administration.

It is not the purpose of this review to comment on the relative merit of the arguments put forth by any of the participants in this debate. Rather, the intent is to describe the process by which succinylcholine became relatively contraindicated in children and adolescents and the ongoing process which will likely result in the removal of the "contraindication' label regarding children and, as an alternative, the establishment of a warning for the manufacturer's package insert.

The Beginning

In 1992, Drs. H. Rosenberg and G. Gronert (1) published a letter in Anesthesiology briefly reviewing four deaths in male children under the age of eight who had received halothane and then succinylcholine. These cases were identified through the Malignant Hyperthermia (MH) Hotline. Reference was also made to "II similar cases" identified through the German MH Hotline. Their letter concluded with the statement: 'We have notified the Food and Drug Administration of this potential problem and recommended that anesthesiologists carefully consider the indications for use of succinylcholine in young children.' This letter was accepted for publication August 24,1992.

Enter the FDA

The Pilot Drug Evaluation Staff of the FDA is responsible for succinylcholine, as it is for all anesthetic drug products.' Pharmaceutical manufacturers and the FDA share responsibility for the proper labeling of all drug products. The labeling of any drug involves an ongoing process. In the case of succinylcholine, four manufacturers exist. Burroughs Wellcome (one of those four manufacturers) prepared an initial draft of a new label. This draft was revised by the Pilot Drug review team.

Enter the Anesthetic and Life Support Drugs Advisory Committee (ALSAC)

This committee serves in an advisory capacity to the Pilot Drug Evaluation Staff of the FDA. The ALSAC committee met on November 23, 1992, and considered the revised labeling of succinylcholine. Representatives from all manufacturers, the committee members, consultants and members of the public were in attendance. Dr. Ed Miller was chairman of the ALSAC committee and led the discussion. Transcripts from that meeting demonstrate that the committee was opposed to the contraindication of succinylcholine in the pediatric population. Rather than recommend even a relative contraindication, the ALSAC members recommended that a warning be added to the labeling of succinylcholine. Subsequent direct communication with the Not Drug Evaluation Staff has confirmed that this recommendation was made. Several months later, however, Burroughs Wellcome renewed dialogue with the FDA and voiced the position that a warning was not acceptable and a contraindication was still being sought. Representatives of Burroughs Wellcome subsequently met with selected members of the ALSAC committee and members of the Pilot Drug Evaluation Staff. As a result of this dialogue a relative contraindication was negotiated rather than the warning initially recommended by the full ALSAC committee. The label change was put into effect by Burroughs Wellcome in November, 1993, and revised package inserts were mailed to practicing anesthesiologists across the country. This relative contraindication reads as follows:

"Except when used for emergency tracheal intubation or in instances where immediate securing of the airway is necessary, succinylcholine is contraindicated in children and adolescent patients..."

Enter Practicing Anesthesiologists

The FDA was clearly surprised at the response that followed the issuing of this contraindication. Thousands of letters and calls were received voicing numerous concerns. The anesthesia literature has been a forum for debating the risk/benefit ratio of succinylcholine relative to the potential for inducing life threatening hyperkalemia in children with undiagnosed myopathies. Badgwell et all (3) and Morell et al (4) published letters of concern in the January, 1994 issue of Anesthesiology, and letters of reply from the Pilot Drug Evaluation Staff (2) and Burroughs Wellcome (5) appeared in that same issue. Lerman et al voiced similar concern in the Canadian Journal of Anaesthesia. (6) The Spring issue of the Anesthesia Patient Safety Foundation Newsletter contained a lengthy debate and editorial on the controversy. (7,8) Committees of the American Society of Anesthesiologists (ASA), the Society for Pediatric Anesthesia (SPA) and the American Academy of Pediatrics (AAP) met to either write opinion letters or statements or form consensus opinions. The FDA responded to all this input.


On June 9, 1994, the ALSAC committee convened on the FDA campus in Rockville, MD. The initial item on the committee's agenda was a reconsideration of the recent label changes regarding succinylcholine's use in children and adolescents. Dr. James Eisenach directed the discussion which opened with a public forum. During this forum more than a dozen distinguished anesthesiologists voiced their objections to the contraindication. These speakers included Drs. Frederic Berry (UVA), Dr. Charles Cote' (Children's Memorial Chicago), Dr. William Greeley (SPA, Duke), Dr. Steven Hall (SPA, Northwestern), Dr. Richard Kaplan (Children's National Medical Center), Dr. Robert Morell (Bowman Gray), Dr. William Ross (UVA), Dr. Theodore Striker (AAP, Children's Hospital Cincinnati), Dr. Thomas Wolfe (Riley Children's Hospital Indianapolis), Dr. Myron Yaster (ASA Committee on Pediatric Anesthesia, Johns Hopkins) and Dr. Marilyn Larach (Penn State Children's Hospital and North American Malignant Hyperthermia Association). AU of these speakers rejected the concept of a contraindication of succinylcholine in children and adolescents. Dr. Uwe Schulte-Sasse (Heidelberg, Germany) presented his data from the German MH Hotline regarding reported cases of hyperkalemic arrest and/or rhabdomyolysis. Following the open public hearing Dr. Ryan Cook (Children's Hospital, Pittsburgh) presented a review of the use of succinylcholine in children. Subsequent to these presentations the members of ALSAC unanimously voted to stand behind their prior recommendation that succinylcholine NOT be contraindicated in children and adolescents. A recommendation was issued to the Pilot Drug Evaluation Staff that, instead, a warning be placed on the front of the package insert. The warning will inform physicians that succinylcholine has been associated with hyperkalemic cardiac arrest in children with undiagnosed myopathies, usually Duchenne's muscular dystrophy. It will also emphasize that male children under the age of eight may be at the greatest risk for developing this rare, yet potentially lethal response. Educational information regarding the appropriate role of intravenous calcium administration will most likely be included.

Interestingly, both the Health Protection Branch of the Canadian government and the Canadian pediatric anaesthetists rejected the 'Dear Doctor' letter sent to all Canadian anaesthetists by Burroughs Wellcome. This letter bore the same contraindication issued in the United States. In late 1993, a revision of that letter was sent to the Health Protection Branch which did not contain the contraindication. Rather, a statement of warning was included which read: 'In infants and children, especially in boys under eight years of age, the rare possibility of inducing life-threatening hyperkalemia in undiagnosed myopathies by the use of succinylcholine must be balanced against the risk of alternative means of securing the airway.' This warning has subsequently been adopted in Canada.

We have come full circle, and that is good, because the process that occurred has served to educate our physicians and our residents. This issue has received a tremendous amount of attention and has heightened our awareness of a rare, but potentially lethal side effect of a commonly used drug. Further, the discussion surrounding this controversy will educate anesthesiologists on the need for prompt and appropriate treatment should hyperkalemic arrest occur. This treatment involves the intravenous administration of calcium. With proper treatment, approximately 50% of patients have survived this catastrophic hyperkalernia. The regulatory process has also educated the public as to the roles played by the FDA, the Pilot Drug Evaluation Staff, the ALSAC Committee, and pharmaceutical manufacturers regarding the labeling of anesthetic drugs. The current ALSAC recommendation is based on the available data and recognizes the risks as well as the unique beneficial characteristics of succinylcholine.

Dr. Morell is from the Department of Anesthesia, The Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, NC.


1. Rosenberg H, Gronert GA: Intractable cardiac arrest in children given succinylcholine. [letter] Anesthesiology 1992;77:1054.

2. Katz L, Wright C, Harter J, Zung M, Scally D, Spyker D: Revised label regarding use of succinylcholine in children and adolescents: 11. [reply] Anesthesiology 1994; 80:24344.

3. Badgwell JM, Hall SC, Lockhart C: Revised label regarding use of succinylcholine in children and adolescents: H. [letter] Anesthesiology 1994; 80: 243.

4. Morell RC, Berman JM, Royster RL, Petrozza PH, Kelly JS, Colonna DM: Revised label regarding use of succinylcholine in children and adolescents: 1. [letter] Anesthesiology 1994; 80: 242.

5. Kent RS: Revised label regarding use of succinylcholine in children and adolescents: 11. [reply] Anesthesiology 1994; SO: 244-45.

6. Lennan J, Berdock SE, Bissonnette B, et al: Succinylcholine warning. Can j Anaesth 1994,41:165.

7. Morell RC, Berman JM (pro); Woelfel SK (Con): In my opinion: a debate: is succinylcholine safe for children? Anesthesia Patient Safety Foundation Newsletter 1994; 9(l):1,3-5.

8. Eichhom JH: Editorial: are we becoming too afraid of complications? Anesthesia Patient Safety Foundation Newsletter 1994; 9(l):2-3.

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126 Papers, Lectures at ASA Highlight Safety

by John H. Eichhorn, M.D.

Patient safety will again be the topic of many presentations at the American Society of Anesthesiologists Annual Meeting, this year to be held in San Francisco October 15-19.

In the Refresher Course Lectures, Dr. Robert Caplan will give lecture # 151 Saturday, October 15 at 9:00 a.m. on 'Adverse Outcomes in Anesthesia Practice' and Dr. Fred Cheney will deliver lecture # 156 the same day at 4:30 p.m. on "The ASA Closed Claims Project: Lessons Learned.' Both speakers are from Seattle and have been principle investigators in the ASA Closed Claims Study, which has contributed significantly to the understanding and improvement of anesthesia patient safety over the last several years.

126 papers in eight scientific sessions of the meeting comprise the section on Patient Safety, Epidemiology, and Education. There are five oral presentation sessions, two poster sessions, and one poster-discussion session.

Cost and Safety

12 presentations on Monday afternoon, October 17, deal with the implications of cost saving strategies in anesthesia practice. For example, Dr. A. Mathieu will present 'Cost-minimization study confirms the safety and cost effectiveness of saving endotracheal tubes after violation of packaging for later usage.'

Blocks, CPR, and Videotape

Tuesday morning, October 18, Dr. S. Palmer will discuss 'Complication rates for major regional blocks are different in general surgery compared to obstetrics' while Dr. N. Jeffries will give a presentation revealing the 'Incidence of procedural errors and critical occurrences associated with tracheal intubation assessed from videotapes and self reports.' Dr. S. Glowacki will ask the highly charged question: 'Can electrocautery transmission induce current in a pulmonary artery catheter?' Other papers in this session will deal with aspects of difficult airway management, errors in CPR, effects of hypothermia, relationship of frequency of post-spinal headache to needle type, and reducing patient risk by doing gasless laparoscopy.

In the Tuesday afternoon oral presentation session, papers will cover postoperative hypoxemia associated with acute pain management guidelines, impact of various QA systems, and the risk factors for dental injury. Drs. L. Mark and C. Cherian win cover different aspects of the Medic Alert Difficult Airway/Intubation Registry.

Panoply of Posters

Tuesdays poster session will feature 30 presentations. Several deal with aspects of transfusion and blood conservation. Reuse of purportedly single use syringes will be covered. Another aspect of possible infection transmission to patients is included in a paper by Dr. A. Layton entitled, "Mycobacterial and pseudomonal contamination of C02 absorber: scrubbed but not clean.' Safety features concerning catheterization of jugular veins as well as new considerations of malignant hyperthermia are also included.

Three poster presentations on anesthesia simulators are included in the Wednesday morning, October 19, poster session. Several more papers concerning safety and performance features of the laryngeal mask airway and its use are also components of this session. Fluoride ion toxicity from sevoflurane use is the subject of a poster and Dr. R. Marcel will present a poster on "Nocturnal hypoxemia following coronary artery bypass graft surgery.' Dr. K Tuman's contribution is 'Effect of beta blocker and calcium channel blocker therapy on MI and death after CABG.' The clinical significance of psychomotor impairment resulting from IV sedation WILL be considered by Dr. R. Thapar. Dr. Y. Wafai revisits the question of the value of the self-inflating bulb for the confirmation of correct tracheal intubation.

Oral presentations concerning anesthesia education will take place Wednesday afternoon. One paper examines the use of the critical incident technique in the performance evaluations of anesthesia residents while another will focus on anxiety and stress reduction among anesthesia residents. Teaching management of the difficult airway is the subject of one presentation. Dr. H. Schaefer concludes the session with a paper entitled, 'Do pilots handle complexity and uncertainty better than anesthesiologists?"

Overall, the 126 papers represent another very strong showing for this section of the ASA annual meeting and ft reflects the ongoing interest in and emphasis on patient safety among anesthesiologists.

Dr. Eichhorn, Professor and Chairman of Anesthesiology at the University of Mississippi School of Medicine Medical Center, is Editor of the APSF Newsletter.

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Editorial: Sux Debate Shows Process of Drug Education

The debate over the use of succinylcholine in children focused the anesthetic community's interest on the interaction between the U.S. Food and Drug Administration (FDA) and 'the drug companies' that manufacture the pharmaceuticals we use daily. Innuendoes that the drug company involved had a vested interest in changing the label was one often heard comment on E-mail. While the debate was lively, there were some important general issues that were brought, to the attention of the anesthetic community and which have generic importance. As the Chairman of the FDA Advisory Committee for Anesthetic Drugs and Life Support, I offer the following observations.

Rapid Consulting

The Advisory Committee of the FDA acts purely as a consultant to the FDA. It does not set policy. It is composed of anesthesiologists, nurse anesthetists, and members from both academic and private practice settings. The FDA also relies on outside consultants to serve on the committee when their expertise will be valuable. The Advisory Committee for Anesthetic Drugs and Life Support is somewhat unusual. It was one of the first of the advisory committees to use a rapid response method for the evaluation of new drugs.

In the past, drug manufacturers submitted products to the FDA for approval. A medical officer at the FDA reviewed the work, and after a lengthy period of time, a decision was made whether this drug should be released to the public. The change in the process was instituted in order to get a more rapid approval of drugs.

Propofol was the first drug approved through the new method. Instead of the bulk of the work being done by the medical officer of the FDA, members of the committee took specific areas and examined them in detail. All members of the committee were involved in writing of the package insert. It should be pointed out that an initial draft of the package insert is written by the drug company and modified by the FDA prior to final acceptance. The package insert is aimed at giving the practitioner as much information as possible in order to use the drug safely. It should be emphasized that drugs once approved by the FDA are available for use by all physicians and not for a group of specialists alone.

New Experience

To re-examine the package insert for succinylcholine was a new experience for this Advisory Committee. The committee was dealing with a known drug that had been given millions of times but a new package insert was being requested. The proposed package insert change came about because of the reported cases of rhabdomyolysis that occurred in apparently healthy children. It was the feeling of the committee, on the initial review, that this was an important finding and that there were children who were dying from the use of this drug. No one knew the incidence of the problem, but it was assumed to be very low. However, it was also argued that these were preventable deaths. The committee debated for a period of time various ways to distribute this information to physicians who use the drug. The deliberations of the committee suggested that a boxed warning be placed in the package insert in order to alert all physicians to this new finding. After meeting with the Advisory Committee, the package insert that appeared contraindicated the use of the drug in children. While I have no special knowledge concerning what transpired after the meeting and before the package insert change, I offer the following insights. The drug company was taking the most conservative possible position in putting out this package insert with the contraindication. They knew there was a problem, though small, with their drug and the best way to protect the company was to insist on the contraindication classification.

Adverse Reaction

Furor over the package insert was intense. Many groups and individuals started a campaign to change or eliminate the formal contraindication of succinylcholine in children. They pointed out many advantages of succinylcholine and argued the point convincingly. The FDA agreed that a more full discussion of the change was indicated. The FDA convened another meeting of the Advisory Committee and invited the anesthetic community to comment on the package insert. The committee reaffirmed its belief that this phenomenon was a problem and again recommended that a boxed warning be placed on the package. The precise warning to appear on the new package insert has not been finalized. However, an initial draft would suggest that the drug company will recommend against the routine use of succinylcholine in children.

Practical Education

The role of the Advisory Committee has served the FDA well. It has tried to bring practical concerns to the FDA at the same time that it considers the welfare of the population on which these drugs are used. Perhaps the succinylcholine debate did more to educate the anesthetic community about the dangers of hyperkalemia in a small subset of children than any other mechanism we presently have available to transmit this information. I also believe that it has given a new importance to the package insert in terms of education and use. One would have to commend the FDA for trying to make the package insert the distillation of all of the important information about a drug that we might administer to our patients.

We all work in our own specific settings and have little knowledge of the practices of others elsewhere. The FDA has a much more complete view of how we as physicians use drugs. Unfortunately, some physicians do not use drugs wisely and the FDA has tried to educate physicians through the package insert. Certainly, the succinylcholine controversy emphasizes that point.

Edward D. Miller, Jr., M.D. Professor and Chairman

Department of Anesthesiology and Critical Care Medicine

The Johns Hopkins Hospital, Baltimore, MD

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Shutdown of Gas Supply System Need Not Be Danger

Planning Minimizes Risks

Editor's Note: This paper is one of a series on medical gas and vacuum systems to be printed in the Newsletter. Dr. Ervin Moss, a member of the Board of Directors of the Anesthesia Patient Safety Foundation and the chairman of the APSF Subcommittee on Medical Gas Vacuum Systems, is coordinating the series.

by Todd G. Peterson, MD, and Fred Evans, PhD

Anesthesia personnel in most operating room settings have come to rely on the Medical Gas Pipeline System (MGPS) as a dependable, very rarely interrupted supply of gases used in the delivery of anesthesia. Tanks are seldom used now except in the administration of anesthesia in places remote from the operating room or in the transportation of patients. As a consequence, anesthesia personnel often lack familiarity with backup plans when medical gas pipelines are shut down for periods of time longer than their machine mounted tank supplies would last. In a planned shutdown of the MGPS, whether for maintenance, modifications or repair, the Anesthesiology Department needs to actively participate throughout the process to assure the uninterrupted flow of gases necessary for safe patient care.

Stages Outlined

A planned shutdown of the MGPS involves three stages: the project definition and preparation prior to shutdown, the actual shutdown and modification of the MGPS, and the recertification of the system after repressurization. Key to minimizing downtime and risks to patients throughout this process are effective communication, preparation, and coordination between hospital departments and services affected by the shutdown and the contractor making modifications. Shutdowns without adequate communication among all those involved have resulted in near crisis situations and even some overt accidents. (1)

The planning process begins with a definition of the scope of the project and should ultimately produce a comprehensive, written shutdown procedure to accomplish the task. The planning process requires an up-to-date, accurate plan of MGPS as actually constructed. Despite the JCAHO requirement for hospitals to have this on file, it is not uncommon for the institution to only have the architect's original plans. (2) In this situation, a careful 'hand over hand' tracing of the system to verify and update the drawings is indicated to prevent unexpected loss of gas supply, prevent construction errors, and minimize downtime, This is also a good time to have a consultant or the internal engineering department reevaluate the MGPS to verify that it continues to meet code requirements and initiate any indicated modifications.

The contractor uses the MGPS drawings to determine how extensive a shutdown is required, to accurately identify the areas affected during the shutdown, to locate valves required for shutdown, and to reasonably estimate downtime. The MGPS, if designed correctly, incorporates a series of shut-off and control valves which include:

1. The source valve located externally directly downstream of the bulk source equipment.

2. The main shut-off valve normally the first valve inside the facility.

3. Riser valves located at the base of each riser in multistory buildings.

4. Floor valves though not required, they are located at each branch off the riser and are used to isolate an entire floor.

5. Zone valves located at eye level along a corridor wall for control of specific areas.

These valves allow for three basic types of shutdowns:

1. Complete shutdown usually done to tie-in a future line to the main or for repairs to the bulk supply source.

2. Riser shutdown: usually done for modifications to an area of the hospital supplied by a single branch (or riser) off the main line.

This most frequently involves service, replacement, or movement of zone valves.

3. Zone shutdown: usually done when desired remodeling and repairs are downstream of specific zone isolation valves.

Prior to any shutdown, the valves required to isolate the construction area are located and tested for internal leakage. Leaky valves can allow nitrogen used in the brazing process to enter and contaminate adjacent zones, or can prevent the plumbers from achieving the gas concentrations within the pipeline required for brazing (0% 02, 100% N2).

Once the contractor determines the extent and duration of shutdown required, the services affected by the shutdown should meet with the contractor to decide on the optimum time and date for the shutdown, to choose a method for supplying medical gases to each patient until the central gas supply is restored, and to define equipment, manpower, and gas supply requirements for that interval. If the shutdown will affect relatively few patients, the simplest alternative supply is through individual supply cylinders, regulators, and backup cylinders for each patient. Patients on ventilators require multiple supply tanks since a single Bear or Servo ventilator uses an "H" cylinder every 4 hours.(3) When larger areas of the hospital are involved, the task of coordinating equipment, supplies, and staff can become very complicated and expensive.

Another acceptable method of supplying the entire system or a portion of a system during a shutdown is to back-feed sections of the MGPS isolated by closing valves either at the riser, branch lines, or zones. Gases are backfed into these sections through inlets placed downstream of the valves. Some such inlets may already exist, such as the Emergency Oxygen inlet which is often used when work is performed on the bulk oxygen supply. Frequently though, inlets need to be installed prior to the planned shut-down. This usually requires a more limited zone shutdown to add an 3" collar inlet downstream of a zone valve. The contractor usually adds these collars to zones which receive little or no use to minimally affect patient care. The inlets must be capable of supplying the flows required by the isolated section without a significant pressure drop or equipment may not function properly. If adequate flow cannot be supplied through a single inlet, the area to be isolated can be broken down into multiple isolated zones, each with an inlet, to meet the anticipated total flow required to provide an adequate alternate supply for each patient's needs.

Though not recommended, some MGPS outlets are used as inlets to back-feed a zone. This is generally considered risky as most outlets are flow limited as a result of their relatively small internal diameter. The use of outlets requires careful verification of adequate back-feed flow capacity prior to their use for a shutdown.

The flow requirements and the expected duration of the shut-down determine the type of alternative gas supply chosen. Large stainless steel containers filled with liquid oxygen, called Liquid Dewars, supply large volumes of oxygen, but are limited in the peak flow they can deliver. High pressure cylinders manifolded together in a 'six pack' contain smaller volumes of gas, but are capable of much higher peak flows. Combinations of Dewars and 'six packs' are sometimes used when high peak flow and high volume use are anticipated. A Y-adapter with check valves attaching the back-feed inlet to the tank supplies permits easy change-over of tanks.



1. How many patient beds will be affected by the shutdown?

2. Of these beds, how many will be occupied by patients requiring pipeline supplies? Which pipeline supplies will be shutdown?

3. How many patients affected by the shutdown will be on ventilators?

4. How many and what brand of ventilators do you use?

5. How many operating rooms will be affected by the shutdown? What OR pipeline supplies will be affected? Which OR pipeline supplies will require alternate sources?

6. How many emergency room beds will be affected by the shutdown?

7. Based on the alternate supply technique chosen, what type and how many flow regulators are needed for floor beds? For ICU beds? For the ORs?

8. Based on the expected maximum duration of the shutdown, what type of gas supply source and how many will be needed for floor beds? For ICU beds? For ORs?

9. How many support stands are needed? Transportation carts? Y-pieces? What other special equipment is required?

10. How much liquid nitrogen will be required for the purge?

11. How many trained staff can be available for the shutdown? How long can they be available? What training have they had?

12. How many personnel will require radio communication equipment?


Based on the alternate gas supply method chosen, each affected service notifies, trains, and schedules adequate numbers of staff to handle any potential problem during the shutdown. Adequate supplies of equipment and gas sources are ordered and a plan for distribution developed. Table I contains a set of questions often used to help determine the equipment and gas supply requirements. If back-feeding a zone is planned, local pipeline supply alarms, especially in critical care areas and the operating rooms, must be tested for proper function. Meanwhile, the MGPS contractor obtains all pipeline components, prefabricating and pressure testing those portions of the project that can be done in advance. The contractor reviews the shutdown valving plan and details the installation plan including the brazing process. He then briefs his installers on the plan and prepares all tools and equipment required during the installation.

Communications Key

The shutdown process begins at the prearranged time only after all supervisors are notified the construction crew is ready, a credentialed Medical Gas System Certifier is present, and adequate alternate gas sources are in position. Communication by radio is essential to coordinate the shutdown process. First, the alternate gas supplies are activated and checked to see that they are capable of supplying the gas needs of all patients affected by the shutdown. These alternate gas supplies are closely monitored throughout the shutdown process and replaced as they become depleted. Once it is verified that patients are adequately supplied from the alternate gas supplies, valves upstream and downstream from the area undergoing modification are closed to isolate the construction zone. These valves should be located by the contractor in advance of the shutdown. With valve closure, the construction crew begins work on the pipeline. Components of the planned modifications are cleaned carefully, then assembled. Prior to brazing, the pipeline is purged with an inert gas, usually nitrogen, until all oxygen is removed. This prevents the formation of copper oxide scale inside the pipeline during the brazing process.

After brazing is completed, the isolated construction zone undergoes pressure testing. If no leaks are found, the nitrogen in the pipeline is then purged using backflow from branch lines (sequentially) and/or the primary source until completely removed from the pipeline system. The primary source is left on-line, and the final stage of the shutdown process recertification begins.

Recertification involves purity and crossover testing of all outlets in the construction and immediately adjacent zones. An independent, credentialed Medical Gas System Certifier should perform these tests and document that each process and procedure of the shutdown was performed correctly. If problems are detected during testing, the installers remain available to correct system flaws or replace malfunctioning pipeline components. As zones are recertified after purity testing, patients are switched from the alternate sources back to the primary gas pipeline system. Upon completion of the recertification testing, all equipment is removed, and all parties the contractor, the institution, and the Certifier must prepare reports on the shutdown.

Thus, the process of shutting down the MGPS is a complex task that potentially exposes patients to greater risks. Good communication and close cooperation between the contractor and institution personnel help to minimize the risks to patients. Uninterrupted medical gas service to patients is a requirement in any shutdown. The anesthesia team needs to understand the MGPS and become an active participant in any shutdown process to maximize safety for their patients.

Guidelines for Planned Medical Gas System Shutdown

Project Definition and Preparation: The goal is to produce a comprehensive written plan of action, and make preparations for the shutdown.

1. Define scope of project. (Institution)

2. Obtain up-to-date plans of the MGPS as actually constructed. (Institution)

3. Determine the areas of the MGPS that will require shutdown. (Contractor)

4. Estimate duration of the required shutdown. (Contractor)

5. Notify affected areas of proposed shutdown. (Institution)

6. Meeting of affected services and contractor to:

a. Set date and time for shutdown. (Joint)

b. Choose method for alternate gas supply. (Joint)

c. Determine equipment and gas supply needs. (Joint)

7. Order equipment and gas supplies. (Either)

8. Coordinate and train staff for shutdown procedure. (Institution)

9. Define and order components for MGPS modification. (Contractor)

10. Prefabricate and pressure test all component assemblies that can be done in advance. (Contractor)

11. Define assembly procedure and preparation process for brazing. (Contractor)

12. Organize and brief installers on plan and policies. (Contractor)

13. Prepare necessary tools, equipment, and material. (Contractor)

14. Arrange for Medical Gas System Certifier. (Joing)

15. Pre-shutdown modifications to MGPS (inlets). (Contractor)

Shutdown Procedure: The goals are a smooth, uninterrupted transition to alternate gas supplies for all patients affected by the shutdown, along with efficient modification to the MGPS.

1. Notify supervisors in all affected areas of the planned shutdown. (Institution)

2. Distribute alternate gas sources and necessary equipment. (Either)

3. Close zone valves and transfer to alternate gas supplies. (Institution)

4. Assure all patients are provided for throughout the procedure. (Institution)

5. Commence shutdown of primary supply. Notify installers. (institution)

6. Vent system gas and purge with nitrogen. (Contractor)

7. Perform planned modifications, assemble components. (Contractor)

8. Purge assembly until 02 Content 0% (Contractor)

9. Verify contents of piping assembly. (Certifier)

10. Braze joints. (Contractor)

11. Pressure test system when done. (Certifier)

12. Vent nitrogen out of system, flush out with primary source and/or backflow from branch lines. (Contractor)

13. Put primary supply back on-he. (Institution)

14. Notify supervisors that construction is completed. (institution)

Recertification: The goals are rapid purity checking to detect system flaws, correct them, and transition patients back to the primary supply.

1. Purity checking of outlets in zones affected by the shutdown. (Certifier)

2. If flaws or other component problems are detected, repair. (Contractor)

3. Return zones to main supply if purity checks OK. (Institution)

4. Discontinue alternate sources, remove equipment for return. (Institution)

5. Remove construction equipment, debris, tools. (Contractor)

6. Reports of shutdown procedure including purity checks. (All three)

7. File copies of summary report and purity checks. (Contractor)

Dr. Peterson is Assistant Clinical Professor of Anesthesiology at the University of Arizona, Phoenix campus, and Dr. Evans is President of Medical Gas Management, Inc., Bethany, Oklahoma. Both are members of the APSF Subcommittee on Medical Gas Vacuum Systems.


1. Feely TW, Hedley-Whyte J: Bulk oxygen and nitrous oxide delivery systems: design and dangers, Anesthesiolog 44:301-305,1976.

2. Moss E. APSF Subcommittee on Medical Gas Systems, April 4,1994 Meeting agenda.

3. Wentling DG. Important Considerations Prior to Hospital Shutdown. BOC Healthcare Memo.

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Letters to the Editor

Duty Fitness Outweighs Question of Aging

To the Editor

Whoa! Things are almost getting out of control. And, all this publicity could begin to go to my head because for one who debuted upon ft planet late in the fall of 1935 to be even tangentially linked to "callow youth" (1) is arguably more praise than damnation!

Let us lay to rest the youth vs. age business. The central issues are indeed fitness for duty (1) and the matching of interests and abilities with tasks. The operating room tasks of an anesthesiologist have been described, as have some common performance shaping factors.(2) Is advancing age with its measurable, but questionably significant decrement in sensory motor function (3,4) an important factor? Let us try to find out.

What seems to have emerged, at least so far in the APSF Newsletter correspondence, 1,1,1 is the following:

1. Age is a sensitive issue; there are concerns at both extremes. (And, we must avoid "endocannibalistic" behavior (7)).

2. The learning curve and the opportunity, if not obligation to teach, continues after residency. We are all students and teachers alike at all stages of our careers.

3. Communication between academic training programs and 'consumers' largely private practicing anesthesiologists or groups can be improved to the benefit of all.

4. Experienced, older clinicians constitute a valuable teaching resource.

If advancing age is judged to be an important performance-modifying factor, then appropriate planning by individuals during residency and for organizations, are appropriate in order to maximize the interests, talents, and capabilities of practicing anesthesiologists also to the benefit of all.

While we work through this (and other things) we may be helped by Voltaire's observation that:

'All of us are formed of frailty and error. Let us mutually pardon each others' folly. That is the first law of nature.' (Essay on Tolerance)

Kenneth W. Travis, MD

Assistant Professor, Anesthesiology Dartmouth-Hitchcock Medical Center Lebanon, NH


1. Lees DE: Letter APSF Newsletter Spring 1994; 9:12.

2. Wenger MB, Englund CE: Ergonomic and human factors affecting anesthetic vigilance and monitoring performance in the operating room environment. Anesthesiology 73:995-1021,1990.

3. Craik FM, Salthouse TA, The Handbook of Aging and Cognition. Laurence Erlbaum Associates Hillsdale, NJ 1992.

4. Dorfman LJ, Bosley TM: Age related changes in peripheral and central nerve conduction in man. Neurology 29:39-44,1979.

5. Lawton TJ: Letter APSF Newsletter Spring 1994; 9:1 1.

6. Travis KW: Letter APSF Newsletter Summer 1993;

7. Pfifferling J-H: in AMA News, Jan. 10, 1994, p. 8.

More on Block Test Chill

To the Editor

The method for testing the "adequacy of regional anesthetic blocks" which Kang describes in her letter 'Big CHI Tests Blocks" (APSF Newsletter, Summer 1994) is commendable in that it avoids, as she says "bloody needle tracks on the patient's body;" however, it does not adequately assess the level of conduction blockade obtained since it is a single application to only a few dermatomes at best. This is fine if these dermatomes coincide with the area of surgical interest, but it will be a very cold day before I will permit intra abdominal surgery based on patient tolerance of a grounding pad on a lower extremity.

Steven C. Chang, MD San Diego, CA

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FDA Publishes Final Version of Revised Apparatus Checkout

Anesthesia Apparatus Checkout Recommendations, 1993

This checkout, or a reasonable equivalent, should be conducted before administration of anesthesia. These recommendations are only valid for an anesthesia system that conforms to current and relevant standards and includes an ascending bellows ventilator and at least the following monitors: capnograph, pulse oximeter, oxygen analyzer, respiratory volume monitor (spirometer) and breathing system pressure monitor with high and low pressure alarms.

This is a guideline which users are encouraged to modify to accommodate differences in equipment design and variations in local clinical practice. Such local modifications should have appropriate peer review. Users should refer to the operator's manual for the manufacturer's specific procedures and precautions, especially the manufacturer's low pressure leak test (step #5).

Emergency Ventilation Equipment

*1. Verify Backup Ventilation Equipment is Available & Functioning

High Pressure System

*2. Check Oxygen Cylinder Supply

a. Open 02 cylinder and verify at least half full (about 1000 psi).

b. Close cylinder.

*3. Check Central Pipeline Supplies

a. Check that hoses are connected and pipeline gauges read about 50 psi.

Low Pressure System

*4. Check Initial Status of Low Pressure System

a. Close flow control valves and turn vaporizers off.

b. Check fill level and tighten vaporizers' filler caps.

*5. Perform Leak Check of Machine Low Pressure System

a. Verify that the machine master switch and flow control valves are OFF.

b. Attach "Suction Bulb" to common (fresh) gas outlet.

c. Squeeze bulb repeatedly until fully collapsed.

d. Verify bulb stays fully collapsed for at least 10 seconds.

e. Open one vaporizer at a time and repeat 'c' and 'd' as above.

f. Remove suction bulb, and reconnect fresh gas hose.

*6. Turn On Machine Master Switch and all other necessary electrical equipment.

*7. Test Flowmeters

a. Adjust flow of all gases through their full range, checking for smooth operation of floats and undamaged flowtubes.

b. Attempt to create a hypoxic 02/N20 mixture and verify correct changes in flow and/or alarm.

Scavenging System

*8. Adjust and Check Scavenging System

a. Ensure proper connections between the scavenging system and both APL (popoff) valve and ventilator relief valve.

b. Adjust waste gas vacuum (if possible).

c. Fully open APL valve and occlude Y piece.

d. With minimum 02 flow, allow scavenger reservoir bag to collapse completely and verify that absorber pressure gauge reads about zero.

e. With the 02 flush activated allow the scavenger reservoir bag to distend fully, and then verify that absorber pressure gauge reads <10 CM-H20.

Breathing System

*9. Calibrate 02 Monitor

a. Ensure monitor reads 2 1 % In room air.

b. Verify low 02 alarm is enabled and functioning.

c. Reinstall sensor in circuit and flush breathing system with 02.

d. Verify that monitor now reads greater than 90%.

10. Check Initial Status of Breathing System

a. Set selector switch to "Bag" mode.

b. Check that breathing circuit is complete, undamaged and unobstructed.

c. Verify that C02 absorbent is adequate.

d. Install breathing circuit accessory equipment (e.g. humidifier, PEEP valve) to be used during the case.

11. Perform Leak Check of the Breathing System

a. Set all gas flows to zero (or minimum). b. Close APL (pop-off) valve and occlude Y-piece.

c. Pressurize breathing system to about 30 CM H20 with 02 flush.

d. Ensure that pressure remains fixed for at least 10 seconds.

e. Open APL (Pop-off) valve and ensure that pressure decreases.

Manual and Automatic Ventilation Systems

12. Test Ventilation Systems and Unidirectional Valves

a. Place a second breathing bag on Y-piece.

b. Set appropriate ventilator parameters for next patient.

c. Switch to automatic ventilation (Ventilator) mode.

d. Fill bellows and breathing bag with 02 flush and then turn ventilator ON.

e. Set 02 flow to minimum, other gas flows to zero.

f. Verify that during inspiration bellows delivers appropriate tidal volume and that during expiration bellows fills completely.

g. Set fresh gas flow to about 5 L/min.

h. Verify that the ventilator bellows and simulated lungs fill, and empty appropriately without sustained pressure at end expiration.

i. Check for proper action of unidirectional valves.

j. Exercise breathing circuit accessories to ensure proper function.

k. Turn ventilator OFF and switch to

manual ventilation (Bag/APL) mode.

1. Ventilate manually and assure inflation and deflation of artificial lungs and appropriate feel of system resistance and compliance.

in. Remove second breathing bag from Y piece.


13. Check, Calibrate and/or Set Alarm Limits of all Monitors

- Capnometer

- Pulse Oximeter

- Oxygen Analyzer

- Respiratory Volume Monitor (Spirometer) Pressure Monitor with High and Low Airway Alarms

Final Position

14. Check Final Status of Machine

a. Vaporizers off

b. APL valve open

c. Selector switch to "Bag" d. All flowmeters to zero

e. Patient suction level adequate

f. Breathing system ready to use

*If an anesthesia provider uses the same machine in successive cases, these steps need not be repeated or may be abbreviated after the initial checkout.

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APSF Grand Patrons Recognized


Ellison C. Pierce, Jr., M.D., President of the Anesthesia Patient Safety Foundation, (right) presents APSF Grand Patron plaque to Dr. Roger G. Stoll, President and CEO of Ohmeda (center) and Dr. Joseph Pepper, President of Ohmeda's Medical Systems Division (left) at a ceremony in the Ohmeda corporate headquarters.


Dr. Pierce (second from right) also traveled to the headquarters of Zeneca Pharmaceuticals Group and presented an APSF Grand Patron plaque to (left to right) Mr. Alan Milbauer, Vice President Pr External Affairs, Mr. Bruce Mather, Anesthesia Products Manager, Mr. Bob Black, President of Zeneca Pharmaceuticals, and (at far right) Mr. Gene Zaiser, Vice President for Sales and Marketing, Hospital Products.

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APSF Clipboard with FDA Checkout on it Again Is Available; Makes Great Gift

A convenient safety tool for anesthesiology practice will once again be available from the APSF. The U.S. Food and Drug Administration accepted the currently approved pre-anesthetic apparatus checklist early this year. The Anesthesia Patient Safety Foundation is pleased to announce that the new APSF clipboard is now in production and available. As with the previous model, the front of the clipboard features an abbreviated list highlighting the main categories of the checklist. The back of the clipboard will display the complete checklist. In the past, the user was asked to refer to the unexpurgated copy (which hopefully was in the drawer of the backstand). Now, both the shorter and long versions will be immediately available.

The clipboard will be available for inspection at the ASA/APSF Safety Booth at the Annual Meeting of ASA in San Francisco. The cost, prepaid, will be $15.00 each, postage included, for orders of 10 or fewer and $12.00 each for orders of eleven or more. To order, write to E.S. Siker, MD, 1400 Locust Street, Pittsburgh, PA 15219-5166. Include your name, address, number ordered and a check made payable to the Anesthesia Patient Safety Foundation.

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