ANESTHESIA PATIENT SAFETY FOUNDATION
NEWSLETTER

Volume 10, No. 2 Summer 1995
Table of Contents

IARS Annual Meeting Includes Safety Topics
In My Opinion: Lack of Outcome Data Makes Reading a Personal Decision, States OR Investigator
Letter to the Editor:
Signs of Safe Sedation Researched, Reviewed
In My Experience:  Non-Cardiogenic Pulmonary Edema After Difficult Intubation
APSF Committee Update
Parenteral Medication Recommendations to be Distributed
Editorial:  Recurrent Issues Prompt Call for Continued Effort
Newsletter Editorial Policy Adopted
Reading Debate Yields Survey Facts, Strongly Opposing Reader Opinions
Memorial Contributions Welcome
APSF Corporate Donors
Notes




IARS Annual Meeting Includes Safety Topics

by Douglas Guyton, M.D.

Patient safety related presentations were featured at the International Anesthesia Research Society annual meeting in Honolulu, Hawaii, March 10-14. Highlights are summarized:

In an award-winning scientific exhibit, Drs. Herbert Ferrari and Charles Bowen (St. Louis University) chronicled the evolution and predicted the future direction of the anesthetic record. Dr. Bowen used the oft-quoted analogy between anesthesia providers and fighter pilots to illustrate his predictions: 'In WWII fighter pilots had only a couple of analog gauges in front of them. As aviation progressed, more and more information became pertinent to the operation of the aircraft, and many pilots flew into the ground as they were attempting to interpret an overwhelming amount of data. Now information is processed so the pilot can make critical decisions quickly, without distracting him from the immediate task of flying the plane.' Just as aviators have come to rely on information processing, Dr. Bowen is convinced that the future of anesthesia management lies in automated information systems.

Automated record keepers and voice recognition systems are tools that will allow the practitioner more time to devote to direct patient observation. Intelligent alarm systems and 'heads-up' displays in visors or eyeglasses which continuously keep vital information in view will rapidly focus attention on important data, allowing the anesthesiologist to intervene earlier during critical events. Although such systems may be perceived initially as distracting toys, the goals of earlier intervention and improved patient safety mandate the development of automated information processing, according to Dr. Bowen.

Regional vs. General

The relative safety of regional vs. general anesthesia was also addressed at the IARS meeting. In his Review Course Lecture, Dr. Michael J. Davies from Melbourne, Australia, outlined perceived distinct advantages of regional anesthesia, particularly for peripheral vascular and carotid artery surgery. Although differences in outcome remain controversial, regional is associated with improved peripheral arterial graft flow rates and decreased risk of arterial thrombosis, he notes. Dr. Davies emphasized the need for further investigation into the role of postoperative epidurals for pain management, which he believes may be associated with improved outcome.

Dr. J. Scharf from the University of South Florida also presented work that suggested spinal anesthesia may be safer than general for patients with cardiac disease. Twenty-nine patients with risk factors for cardiac disease were randomized to either spinal or general anesthesia for procedures of the lower extremity, genito-urinary tract, and lower abdomen. Patients undergoing spinal anesthesia had significantly less myocardial ischemia than patients who received general anesthesia, however no outcome data were reported. ['And debate goes on, and debate goes on.']

Residual Paralysis

Two separate reports examined the residual effects of muscle relaxants in PACU patients. Despite using different techniques (neuromuscular stimulation vs. pulse oximetry and physician assessment) both studies found that approximately 15-20% of patients had significantly impaired neuromuscular function on arrival in PACU. Preliminary results from a multi-center study of mivacurium and vecuronium revealed a number of possible risk factors for poor postoperative ventilatory status, including induction with thiopental and pre-existing renal disease. Identification of high-risk patients may help avoid the potentially disastrous consequences of postoperative ventilatory insufficiency.

Two devices designed to confirm endotracheal tube placement were validated for pediatric use. In a series of 248 patients, a self-inflating bulb correctly identified 10 esophageal intubations but failed to confirm tracheal intubation in one morbidly obese patient. A disposable, colorimetric C02 detector was tested in an in vitro experiment by Dr. Eugene Freid at the University of North Carolina. Accuracy ranged from 86 to 100%, falling off with small tidal volumes (5-10 n-d) and rapid rates (60 breaths/min). Dr. Freid was convinced of the device's utility, saying "Nothing is perfect, but this certainly adds to the clinician's armamentarium, especially when operating under adverse conditions.' He noted that emergency personnel had already used the device to correctly confirm endotracheal tube placement in pediatric patients when other techniques were equivocal.

Preop Testing Dangers

In a review course lecture, Dr. Michael F. Roizen (University of Chicago) emphasized the value of the preoperative medical history in anticipating problems and planning therapies accordingly. He also urged using the history to decide which laboratory tests are indicated and relies on a written algorithm to assist him in his own practice. He believes using such a strategy not only lowers costs but may also reduce patient harm from therapies initiated by false positive test results. In support of his beliefs, Dr. Roizen reviewed several studies of patients who underwent laboratory testing without indicated need and showed that fewer patients may have benefited from such screening than were exposed to potential harm by treatment and follow-up of false positive results. A benefit/risk analysis on routine preoperative chest x-rays also showed more harm resulted than good. Dr. Roizen underscored the necessity of a thorough preoperative medical history and the rationale for laboratory testing based on indications and not merely for screening purposes.

Dantrolene Absence Cited as Risk

Dr. R.F. Kaplan (Children's National Medical Center, Washington, DC) surveyed the availability of dantrolene in hospitals, surgicenters, and oral surgery centers to assess the impact of education and increased awareness since the last survey in 1988. He found that 43% of hospitals, 68% of surgicenters, and 85% of oral surgery centers are not equipped to fully treat a case of malignant hyperthermia. 'Despite our educational efforts, this represents no change over the past six years in the percentage of institutions using triggering agents that are fully prepared to treat MH. It appears that a more aggressive approach may be necessary to assure all of these institutions are equipped to handle such a life-threatening emergency.'

Citing concerns over reports of increased infection rates in ICU patients receiving continuous propofol infusions for sedation, Dr. P.B. Langevin (University of Florida) re-examined growth rates of staphylococcus aureus in propofol and intralipid. He found that when incubated in a plastic container, such as a disposable syringe, bacterial growth was delayed for approximately eight hours. Bacterial growth is immediate when incubated in glass containers, which contain nitrogen in residues from prior washing. From his studies, Dr. Langevin has concluded that factors other than simple bacterial replication may be responsible for the increased number of staphylococcal infections associated with propofol. 'One possible explanation could be an interaction between propofol and the bacterial cell membrane, altering the antigenicity of the bacteria and reducing the body's ability to fight infection.'

Dr. Z. Fang (University of California, San Francisco) examined the production of carbon monoxide (CO) from C02 absorbents acting on volatile agents. [See APSF Newsletter, Fall 1994.1 While CO rarely accumulates in appreciable levels, certain conditions favor its production and may lead to significant exposure to patients. Dryness of absorbent was the most significant factor favoring CO production, with increased temperature, high agent concentrations and type of absorbent (Baralyme > soda lime) also contributory. Dr. Fang suggested that drying of the absorbent from running high gas flows through a circuit over a weekend may cause a risk when halogenated ethers are used during the first case Monday morning.

Gastric emptying times after a fight breakfast of toast, coffee and clear juice were measured by ultrasonography in a joint study from several Norwegian institutions. The investigators found that in healthy patients without gastric motility problems, such a meal cleared in three to four hours, with large interindividual differences. They concluded that a six hour fast should be mandatory after a light meal in order to provide a safety margin for smokers and other patients with unrecognized delayed gastric emptying.

Dr. Guyton is from the Department of Anesthesiology, University of Mississippi Medical Center, Jackson.

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In My Opinion: Lack of Outcome Data Makes Reading a Personal Decision, States OR Investigator

by Matthew B. Weinger, M.D.

I have been invited to comment on the appropriateness of the anesthesiologist reading while tending to an anesthetized patient, an issue raised recently in this Newsletter. (1) First off, I would like to emphasize that there are no scientific data on the impact of reading on anesthesia provider vigilance or task performance. Thus, all further discussion must be either -1 personal opinion or 2 reasoned hypotheses based on data from related endeavors/venues. I hope to present an argument based on the latter approach.

Most of the time during the administration of an anesthetic, there are many patient-care tasks to perform and the diligent anesthesia provider will prioritize and undertake these tasks appropriately. Under this circumstance, if reading occurs, it will only be during 'idle time' when no other tasks (other than general patient monitoring) are required. In the study by Drui and colleagues (2) the anesthesiologist was 'idle' during 40% of routine cases. This idle time is essential because it acts as a reserve (e.g., spare capacity) to be called into play during critical events when additional cognitive and physical resources must be rapidly deployed to optimize patient care.

Recent studies suggest that more experienced providers will perform tasks more efficiently, report lower workload, and have more spare capacity at a given level of task performance.(3) I would assert that most anesthesia providers read during these idle periods to prevent boredom. Boredom is a problem of information underload, insufficient work challenge, and under-stimulation. (4) Boredom appears to be a major problem in many complex real-life tasks. For example, boredom may be a contributing factor to human error in locomotive driving and in prolonged routine flight in high-performance and commercial aircraft. Low workload may result in a low arousal state which can lead to impaired performance. (5) In laboratory experiments, increased effort in the presence of boredom is necessary to suppress distracting stimuli and a generalized feeling of fatigue. (6) Adding tasks to a monotonous job may decrease boredom and dividing attention among several tasks (time-sharing) may, in some circumstances, actually improve monitoring performance (7,8)

"Alternative" Tasks

Observation of private anesthesia practitioners has revealed that, during times of low workload, many add an additional task to their routine. These secondary tasks include clinically-relevant functions such as rechecking the composition or organization of the anesthesia workspace. Alternatively, it is common to observe anesthesiologists reading, listening to music, attending to personal hygiene, or conversing with their intraoperative colleagues about matters unrelated to patient care.

Survey Done

Few studies have defined the actual incidence of boredom or of reading in the operating room. A few years ago, I asked 105 anesthesia providers at the University of California, San Diego, to complete a questionnaire on human factors in anesthesia practice. This questionnaire included questions on the occurrence of boredom and the frequency of reading in the OR. Fifty-seven anesthesia faculty, residents, and CRNAs returned the questionnaire (54% response rate). The respondents were bored only infrequently while administering anesthesia although almost 90% admitted to occasional episodes of 'extreme' boredom. To relieve their boredom while in the operating room, 29% of the respondents read. When asked specifically 'how often do you read while administering anesthesia,' 19% of the respondents stated that they 'frequently' read, 46% said they 'sometimes' read, and 33% 'rarely' read. Only one respondent .never' reads in the OR. Forty-nine percent of the respondents felt that reading detracted from anesthesia vigilance while 21 % believed that reading enhanced vigilance and 30% were ambivalent. I believe that these results are representative of many anesthesia departments throughout the United States. Thus, during anesthetic cases that are long and impose minimal physical and intellectual demands, the addition of non-patient care tasks such as reading appears to be quite common. To the extent that the addition of these secondary tasks prevent boredom, they could improve vigilance by maintaining arousal.

The choice of reading material may make a difference. In our questionnaire, the vast majority of respondents almost always read anesthesia-related materials. However, these individuals were from an academic institution and I suspect that non-medical reading material is more common in community hospital operating rooms. Nevertheless, I would postulate that mentally absorbing or engrossing reading materials (e.g., fictional novels) would be more likely to impair vigilance. It should be noted that there are potentially significant adverse medicolegal implications of reading in the OR if an acute critical event is not detected or managed appropriately.

Time Sharing

Laboratory studies suggest that there is a discrete time-sharing ability which can be separated from other vigilance skills (9,10) but may be able to be trained. However, anesthesia providers are not given any formal training in time-sharing techniques although 'resource allocation' and 'divided attention' skills are probably learned on an informal basis. There is probably tremendous individual variability in the impact of reading on anesthesia vigilance. For some anesthesia providers, intraoperative vigilance could be enhanced by reading during low workload periods, while in others, their ability to detect acute events may be impaired.

No Clear Recommendation

At this time, in the absence of controlled studies on the effect of reading in the operating room on anesthesia vigilance and task performance, no definitive or generalizable recommendations can be made. The decision must remain a personal one based on recognition of one's capabilities and limitations. From a broader perspective, the anesthesia task including associated equipment must be optimized to minimize boredom and yet not be so continuously busy as to be stressful. This will yield the highest consistent levels of vigilance and optimal performance for all anesthesiologists.

Dr. Weinger is Associate Professor of Anesthesiology, University of California, San Diego, and Staff Physician, San Diego VA Medical Center.

References

1. Bostek CC: Is it OK to read during OR cases? APSF Newsletter 9:45,1995.

2. Drui AB, Behm RJ, Martin WE: Predesign investigation of the anesthesia operational environment. Anesth Analg 52:5W591,1973.

3. Weinger MB, Herndon OW, Paulus MP, Gaba D, Zornow MH, Dallen LD: Objective task analysis and workload assessment of anesthesia providers. Anesthesiology SO: 77-92,1994.

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

5. Boadle 1: Vigilance and simulated night driving. Ergonomics 19: 217-225,1976.

6. Davies DR, Shakleton VJ, Parasuraman R: Monotony and boredom, Stress and fatigue in human performance. Edited by Hockey GRJ. Chichester, England, John Wiley and Sons, 1983, PP. 1-32.

7. Gould JD, Schaffer A: The effects of divided attention on visual monitoring of multi-channel displays. Hum Factors 9:191-202,1967.

8. Haskell BE, Reid GB: The subjective perception of workload in low-time private pilots: a preliminary study. Aviat Space Environ Med 58:1230-1232,1987.

9. Jennings AE, Chiles WD: An investigation of timesharing ability as a factor in complex performance. Hum Factors 19: 535-547, 1977.

10. Siering GD, Stone LW: In search of a time-sharing ability in zero-input tracking analyzer scores. Aviat Space Environ Med 57:1194-1197,1986

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Letter to the Editor:

Issues Are Not Absolute; Aspersions Inappropriate

To the Editor:

I am prompted to write by the recent letters regarding reading in the operating room. I am unconcerned about the argument per se. I am very concerned about the language used by those expressing opinion There are few systematic data to support either side of the argument. In spite of this paucity, contributors have impugned the honesty, integrity, and professional devotion of many practitioners. If we are to be viewed as credible scientists and professionals, we must not stoop to casting aspersions about our colleagues based purely on personal bias.

A negative answer begs the question: 'Aren't all distractions the same?' Is there really a difference between reading and a friendly discussion with the surgeon regarding politics, investments, or professional sports? Is music a distractions Who completes post-operative analgesia orders or answers pages from the recovery room during a case? Lastly, who among us sits silently amid the buzzes and beeps speaking to others only as regards contemporaneous patient care issues and attending to nothing else? It is no more inconceivable that if there are those who can perform the activities I've mentioned, then perhaps there are also those who can read during a case. Is it possible that reading might be compromised rather than care?

If we abandon respect for diversity of professional skills and data-driven scientific integrity in favor of emotional and opinionated 'stone throwing' we should be very careful. The stones may bounce back.

John K. Hall, M.D.

Nemours Children's Clinic Jacksonville, FL

Reading in OR is Appalling

To the Editor

With thirty-plus years of experience in risk management activities involving medical malpractice, I find it extremely interesting, and with considerable trepidation, that anesthesiologists feel they can divide their attention between constant observation of their patient and reading a novel. In your Spring 1995 APSF Newsletter, I read with great interest the reaction of many of your other readers. The opinion of the physician from Sudbury, Ontario, who felt that it was perfectly all right to read in an effort to keep sharp and away from boredom while doing a case is appalling.

This physician seems to feel that no matter what occurs, and whether he's distracted or not, he is still in complete control. It appears that he accomplished several outside tasks while attending a case, including reading the APSF Newsletter and writing a draft. I wonder if this same physician also reduced his fee for the period of time he was not attending the patient.

Any type of reading that doesn't pertain to the particular procedure being performed at the time, and that interferes with the unwavering care of the patient, should not be tolerated in any form.

Garth M. Newman, CSP

Vice President, Loss Control

O'Rourke, Andrews & Maroney, Inc. Fort Wayne, IN

Reading Debate Shows Bias

To the Editor

Attacks against the practice of anesthesia personnel reading in the OR certainly are biased. I agree that the practice is detrimental to a positive image of the vigilant anesthesiologist or anesthetist.

If reading is detrimental, why is not any conversation with other persons in the OR, surgeon and nurses, over topics usually unrelated to patient care just as onerous? Is listening to music or daydreaming about our daily lives to be condemned? Should telephone conversation be prohibited? Does not conversational teaching with a resident detract from vigilance? Does fatigue diminish vigilance?

Where is the data to support the contention that reading or any other distraction from direct patient care mentioned influences outcome?

Any legislation concerning vigilance should be taken very cautiously; we do not need any more ammunition for plaintiffs' lawyers to use against us.

Trey Flewellen, M.D., DABA Carrollton, TX
 

Debate on OR Reading Provides Very Varied Views

To the Editor

I am writing this in response to the issue "Is it O.K. to read during OR cases?' which was raised in the Winter 1994-95 APSF Newsletter.

Obviously, the knee-jerk answer is that reading during cases is inappropriate and any anesthesia caregiver feeling the need to be politically correct will answer in this way.

However, I would like to make a number of points relevant to this question. First, I believe reading during cases is acceptable when it occurs during selected, appropriate cases. In cases requiring few, if any, anesthetic interventions over long periods of time, anesthesia personnel can, in reality, be found passing time in a number of different ways. Some may discuss sports or politics, tell jokes, talk quietly with OR personnel, doodle, daydream or stare at the monitors. Some may choose to read. We have all been in one or another of the above situations without compromising our care of the patient. I believe, therefore, that for experienced caregivers, the decision in this matter is a personal one. Each and every one of us knows how diligent we must be and, depending on the situation, can choose to read without reducing our effectiveness as anesthesia care providers.

Second, the issue of reading is all encompassing. In no way do I feel that an argument can be made wherein it is acceptable to read a medical journal, but a newspaper is taboo. Reading is reading. It may be cosmetically more appealing to read a Journal; however, in practical terms there is no difference. Cosmetics, however, may be quite politically correct.

In responding to Mr. Bostek's query, therefore, I do believe that a caring, dedicated anesthesiologist may, in selected cases, choose to read and do so without, in any way, lessening the care being given to the patient. Understandably, this may not be for everyone, and, as an anesthesiologist, I feel I must limit my opinion to physicians.

W. Goldstein, M.D.

Anesthesia by ESP?

To the Editor.

I've always thought of those many M.D.s and some CRNA's, who read while administering anesthesia, as "real experts." Apparently they are capable of administering anesthesia by E.S.P.!

Peggy Terpening, CRNA Gentry, AR
 

RSA Reader Suggests Watching Surgeon, Asks What is "Anesthesiologist Personality"

To the Editor

I respond enthusiastically to your invitation in the Winter 1994-95 APSF Newsletter to contribute to the debate on reading in the OR.

Lt. Col. Bostek (1) has demonstrated outstanding performance on two levels: personally, in eschewing the habit of reading in the OR in order to concentrate on his duties and, generally, by highlighting this major cause of poor performance in anesthesia providers.

In admitting that reading sometimes deafened him to questions from the surgeon, he has also drawn attention to an important aspect of anesthesia monitoring which is very seldom publicly addressed.

The performance of the surgeon also requires constant monitoring to help achieve a safe anesthetic!

One cannot depend upon the anesthesia machine and its concomitant gadgetry nor on the surgical assistants for the performance of this vital aspect of patient safety.

Sitting in the corner of the OR reading a journal kills the opportunity to warn the surgeon that the extra pack or retractor he is busy inserting in the abdominal cavity may very likely compress the inferior vena cava. This will ultimately trigger the cardiac monitor and initiate chaos, but an ounce of prevention is worth a ton of treatment. Experienced anesthesiologists can supply a multitude of examples of other deviations from optimal surgical practice. The complications are inevitably attributed (indirectly but rightly) to the anesthetic deliverer. He or she should not feel aggrieved if all had apparently been peaceful while they were engrossed in reading a journal!

One must, of course, possess the background knowledge to be able to detect defects in surgical technique. One must also be very diplomatic in drawing these to the attention of the surgeon except in those few cases where it is necessary to arouse him or her from a trance like state.

One of the virtues of the old-fashioned open-drop ether technique was the absolute necessity for the anesthetist to watch everybody and everything that went on in the OR every minute of the anesthetic; and very particularly what the surgeon was doing!

This excluded any possibility of developing boredom.

Boredom is the primary reason for seeking distraction by reading in the OR. A bored anesthetist is a very dangerous anesthetist. In the several departments I controlled during my career, a bored anesthetist was a candidate for the firing squad and was told not to approach the hiring squad while I was still around! Lt. Col. Bostek has my fullest support.

I received in the same postal delivery the April issue of the continuing education organ of the South Africa Medical Association and include below the editors comment in an amateur's translation of the Afrikaans. Of course, radiology (or whatever that discipline is now termed) and pathology are also refuges for doctors who discover too late that they should have been in another professional field entirely.

I wonder what percentage of anesthesiologists have drifted into the specialty for this reason? I have never seen any in-depth study of the ideal psychological profile to a good anesthetist. This is an aspect of safety in the specialty which may be of much greater importance than one realizes.

Reprinted from CME, April 1995, vol, 13, no. 4, p. 347: Caveat medicus

by F. N. Sanders, BDS

A young doctor who worked in a family-oriented general practice said to me one day: 'I wish these people would stop bringing me their problems. What do they expect me to do about them?' A few further remarks made me realize that the doctor believed that these patients, who sought advice and reassurance, were weak and stupid. One wonders how the patients would have felt if they had been aware of his attitude. The doctor happens to be extremely intelligent, but as a student should perhaps have been advised to choose another profession. That particular doctor now specializes in anesthesiology which suggests a wish to divorce the patient from the doctor. This practitioner should actually realize that an anesthetist cannot necessarily avoid contact with patients. This is an instance where the doctor-patient relationship is threatened and apparently irreparably damaged. AB doctors should guard against this concept.

Cecil Stanley Jones, D.A. Consultant Anaesthetist Sangrove Rondebosch, Republic of South Africa

Reference

1. Bostek, CC. Is it OK to read during OR cases?(Letter) APSF Newsletter 1994-1995,9:45.

Thoughtful Alternative Views Mark OR Reading Discussion

Vigilance Outweighs Reading Concerns

To the Editor

I have read with interest both the original letter and its many responses concerning reading in the OR during cases. As a practicing anesthesiologist, and as the Chairman of Anesthesiology in a large private hospital, I feel that some important points have thus far been overlooked. First, let it be clear that no one in this debate disputes the need for vigilance during the provision of anesthesia care (whether MAC or any other type).

The debate concerns the questions 'What is the necessary and appropriate level of vigilance?', and 'How best can we assure that level of vigilance?' Certainly, the necessary level of vigilance varies during the provision of anesthesia care. Rapidly changing clinical situations (i.e., induction and emergence, highly invasive surgical procedures, the .unstable' patient, etc.) require the full and constant attention of the anesthesiologist, and none among us would argue with that.

However, anyone who has personally provided anesthesia care for very long will attest that, when anesthesia is done deftly, there are often long periods of clinical and physiologic stability. While certainly these times require sufficient vigilance to assure that such stability persists, even the most thorough evaluation of the patient, the surgery, and the monitors requires only five or ten seconds. Even if repeated twice a minute, more than two-thirds of one's time is "unoccupied', and even the 'occupied' time contains no novel stimuli.

A number of studies, in our field and others, have addressed the problem of how to best maintain vigilance in a monotonous or non-stimulating environment (such as these long periods of intraoperative stability), and almost all conclude that even with the best of intentions, without varied stimuli there can be frequent lapses in vigilance. Those who claim that their vigilance is 'unflagging' in these situations may be unaware of their own lapses.

Some of us clearly feel that the appropriate use of reading materials during the intervals between evaluations can enhance their overall attentiveness others clearly find it to reduce theirs. Probably, no single, absolute 'rule' on the subject will be feasible.

However, reading is by no means the only potential obstacle to vigilance in the OR. I have found that of equal concern are the use of the telephone (whether for clinical or other purposes), record keeping (clinical or personal), and even impassioned conversation with the surgeon. Any of these can and has led to decreased vigilance. (I once received a report of an anesthesiologist who was said to be inadequately vigilant-he was on the phone to the MH Hot Line!)

Lastly, I must comment on the ubiquity of the practice. Except for academic or training situations (which rarely provide the aforementioned 'periods of stability" required), almost all of those who personally provide anesthesia care will at some times read, talk on the telephone, or engage in other "nonclinical" behaviors that could potentially decrease their vigilance. In some situations, these behaviors are both necessary and appropriate, and may actually improve the quality of care.

However, none of " relieves the practitioner of his or her responsibility to provide adequate vigilance and care, in any and all situations. It is for each of us to determine how best to provide this in our own practice of anesthesia.

William F. Styler, D.O. Greenwood Village, CO

Looong Surgery = Reading

To the Editor

This is in response to the unnamed surgeon and his observations of his anesthesia colleagues. Having practiced anesthesiology for 32 years, I feel the issue of reading in the OR is quite simple. If it interferes with your vigilance, don't do it; if it improves your vigilance at appropriate times, fine. It should be done at the individual's discretion, providing his or her anesthesia associates don't consider that patient care is being compromised.

When a surgeon routinely takes eight hours or more, for example, to perform a peripheral vascular procedure on a stable patient, the anesthetist would have to be more dim-witted than the surgeon if he or she couldn't read (or converse with the OR staff, for that matter) at selected appropriate times during the case.

If the unnamed surgeon, instead of critiquing the anesthesia care, were to consider devoting some time to help prevent such surgical outrages, patient care would truly be better served, and patients' families spared the needless expense of surgical inefficiency.

Kenneth J. Cestone, M.D. Bennington, VT

Reading = Distraction

To the Editor:

This is in response to the Winter edition containing a 'Letter to the Editor' regarding reading during administration of anesthesia.

In our department, we discourage reading of any type during the administration of anesthesia. Reading seems to distract from the ability of the anesthesia care provider to properly observe and monitor patients appropriately. It also creates a poor image that many of our surgical colleagues often have regarding anesthesiologists. Reading gives an impression of a lack of interest in the operative procedure and patient care. On the other hand, during a long case with a stable patient it may tend to maintain individual alertness by not allowing thought processes to drift or 'mentally doze.' As a rule, I feel it is inappropriate to read during the administration of anesthesia.

I have discussed this with several of my colleagues and they generally feel the same. Concerning the lack of attention during a protracted case, my personal preference is to increase the involvement and observation of the surgical procedure and monitoring. This may be accomplished by physically moving around in the room, observing the operation, discussing progress with the surgeon, etc. Even during prolonged procedures, I find this to be the best and most professionally appropriate method for maintaining attentiveness during a surgical procedure.

Mack A. Thomas, M.D. Chief, Anesthesiology

LSU School of Medicine New Orleans, LA
 
 

An Impending Accident?

To the Editor

In regard to the Winter 'Letter to the Editor' topic of 'reading during cases, both related medical literature and non-medical pleasure reading,' I agree with the letter writer. Distracting yourself places the patient at risk.

I have often wondered how many of those auto drivers who drink coffee, talk on the phone and comb their hair while changing lanes on the expressway end up causing an accident.

Christine Molchan, CRNA Riverview, MI
 

Reading's Effect on Anesthetic Outcome, Image to Surgeon Cited; Sux Debated Again

To the Editor

I found the Spring issue of the APSF Newsletter to be the most thought provoking and controversial issue to date. Whether or not reading in the operating room disparages the image of the Anesthesia Care Team member is not the issue. Does it affect the outcome of the case? Too often studies are based on the investigation of one variable, but rarely do we read of outcome studies. Perhaps if anesthesiologists at teaching institutions spent most (if not all) of their time teaching in the operating rooms each and every case, residents would not feel compelled to read during the case to supplement the lack of information provided via less-than-optimal lecture series. This would help to overcome the image of the anesthesiologist working on his personal finances on his laptop in the OR so shamelessly painted by the surgeon who chose to remain anonymous. I assume that this vigilant surgeon is always in the operating room, from induction of anesthesia to the transfer to the cart at the end of the case, even though he works at six different facilities.

The controversy over succinylcholine use will continue to rage on for years until a non-depolarizing neuromuscular blocking drug is developed that mimics succinylcholine in onset, duration, and cost yet has no side effects or active metabolites. Dr. Steven S. Kron, in his letter to the editor (APSF Newsletter Vol. 10, No. 1, p. 2) promulgates the use of less costly drugs, such as pancuronium, metocurine, curare and succinylcholine drips based solely on estimated length of time the case will take. Once again, the use of outcome studies proves this line of thinking based entirely on cost to increase risk to the patient by having unrecognized residual neuromuscular blockade present in the recovery room from using such long-acting, yet cheap, drugs. Dr. Kron fags to mention the cost of adjuvant drugs to offset the side effects of or to reverse these cheaper drugs. This type of misinformation leads practitioners or those in training to believe that we are doing patients a service by using the cheaper drug. While cost is an issue, safety comes first. We have the ability to provide anesthesia that is safer today than ever before, partly due to the development of newer and better drugs with safer profiles. Forcing residents in anesthesia training programs to use pancuronium on any case longer than "x' minutes denigrates them to the 'tube tech' image we must avoid. Residents are there to learn the art of administering anesthesia with various techniques, drugs and approaches. To stifle them is to lose what our specialty thrives on, i.e., the knowledge of and ability to use all drugs in our armamentarium and to use these drugs appropriately in each situation. This is what the American Board of Anesthesiology promotes when granting the title of Diplomate as a consultant in anesthesiology.

Thomas W. Durick, M.D. Chief of Anesthesia: Meadville (PA) Medical Center

Breathing Circuit Disconnects, Leaks Could be Prevented with Locking Pin

To the Editor

In order to decrease the frequency of breathing circuit disconnections or leaks, a type of mechanism (which is already used on some central venous catheter systems) involving a pin on the male end that is twisted with a half-turn into a groove on the female end could also be used on breathing circuits. This mechanism could be used at the attachment of the breathing circuit both to the machine and to the mask or endotracheal tube. This mechanism has the advantage of allowing the individual practitioner to choose whether to simply attach the circuit as we do now, or to twist the circuit to lock the attachment. One might choose not to lock the breathing circuit to the endotracheal tube, so that accidental stretch on the circuit might disconnect the circuit but not pull out the endotracheal tube; indeed, it might be preferable to have this mechanism only on the proximal end of the breathing circuit.

Another useful modification of breathing circuits would be to have the adapter site for the airway temperature probe closed with a luer-lock device rather than with a simple pop-off cap, to decrease the chances of accidental dislodgment of the cap. I once pressure-tested my circuit, preoxygenated the patient, induced anesthesia, then found that I had accidentally and unknowingly dislodged that cap while moving the circuit to preoxygenate the patient, resulting in a huge air leak and an inability to ventilate the patient until I found the source of the leak. This took longer than I would have liked, as I had not used that type of breathing circuit before, and as the open site was pointed down. I discovered the leak just as the patient began breathing spontaneously again as the pentothal was wearing off, fortunately I had not given muscle relaxants as I was planning to do this brief case by mask with assisted ventilation, so the patient did not develop hypoxemia or suffer any injury.

I would appreciate any assistance in communicating these suggestions to the appropriate ASA and manufacturer's safety and standards committees.

David Blatt, M.D. Covina, CA
 

Safety of 5% Lidocaine Heavily Defended

To the Editor

In 1993, a Swiss article (1) reported transient neurologic toxicity after hyperbaric spinal anesthesia with 5% lidocaine. This article was accompanied by an editorial (2) that essentially condemned the use of 5% lidocaine in 7.5% dextrose for spiral anesthesia. Subsequent correspondence in that Journal debated the issue of neurotoxicity from lidocaine focusing on 'heavy' versus 'light' and the development of cauda equina syndrome in conjunction with continuous spinal anesthesia with hyperbaric 5% lidocaine. (3)

The number of spinal anesthetics performed in the United States with 5% hyperbaric lidocaine annually is probably somewhere between 500,000 and 1,000,000. Many clinicians consider single-dose hyperbaric spinal lidocaine the anesthetic of choice for patients undergoing transurethral resection of the prostate or fixation of a fractured hip. In our risk management database, we have 3,372 administrations of single dose 5% hyperbaric lidocaine without known neurologic sequelae. If single dose hyperbaric lidocaine is indeed neurotoxic, we should be observing the results of this neurotoxicity across the United States. In terms of onset, duration of action and success rate, 5% hyperbaric lidocaine deposited in the subarachnoid space is ideal for a subgroup of patients having particular procedures, as previously mentioned. There is no comparable pharmacologic alternative for the practitioner. Although the Swiss study is interesting, it must be viewed as a clinical aberration with questionable implications for subarachnoid Lidocaine.

It is inappropriate to deprive the clinician in the United States of a valuable local anesthetic for subarachnoid anesthesia. More importantly, our patients should not be denied the use of heavy lidocaine for spinal anesthesia. We have communicated with many clinicians throughout the United States and all indicate that they continue to use single dose 5% hyperbaric lidocaine for spinal anesthesia, especially for patients undergoing TURP and hip fracture fixation. We will continue to do likewise as we consider single dose hyperbaric lidocaine to be the best local anesthetic for spinal anesthesia in our patients. We are optimistic that experienced investigators will prospectively evaluate the issue of neurotoxicity secondary to single dose 5% hyperbaric lidocaine and settle the issue. Throughout the years, our specialty has been plagued with the phenomena of "finger pointing' at the wrong variable (such as the suggestion that isoflurane causes cancer).

In the United States, single dose 5% hyperbaric lidocaine for spinal anesthesia has stood the test of time. It should and will continue to be used by clinicians when indicated.

Casey D. Blitt, M.D.

Old Pueblo Anesthesia Tucson, AZ

References

1. Schneider M, Ettlin T, Kaufmann M. et al. Transient Neurologic Toxicity after Hyperbaric Subarachnoid Anesthesia with 5% Lidocaine. Anes and Analg 1993; 76:1154-7.

2. deJong, RH. Last Round for a 'Heavyweight? Anes and Analg 1994; 78:3-4.

3. Thompson, GE. This Fight Isn't Fair. Anesth and Analg 1994; 79:604-605.

More "Adequate" Sedation

To the Editor

I was interested that Dr. Shea proposes an eponymous sign for when her patients go 'poof' or 'pouf' during sedation. (1) It seems that her techniques sometimes result in loss of consciousness, since she 'sometimes wakes them up" whilst gauging the level of sedation.

Many anesthesiologists would not support this. Sedation is defined as "a mild state of cortical depression in which the patient is calm and tranquil but awake." (2) This avoids the risks resulting from hypnosis (a drug-induced sleep), such as disinhibition, involuntary movement, coughing, straining, obstruction, etc.

"Conscious sedation is an art not easily learned" (3) and anesthetic immortality is not easily earned.

Incidentally, Webster's Third International Edition defines 'Pouf' as (a) something that is inflated or insubstantial (b) bouffant or fluffy part of a garment or clothing (c) an evanescent whiff (as of smoke). The latter is appropriate, since the Greek word 'capnos', 'smoke', is the root for capnography, which is of course our useful respiratory monitoring system.

David R. Ball, MBBS

Department of Anesthesiology UCI Medical Center Orange, CA

References

1. Shea K. Is the patient adequately sedated? (letter). APSF Newsletter, Spring 1994; 9:12.

2. Collins VJ (ed) Principles of Anesthesiology, 3rd ed, Lea and Febiger, (1993), p. 288.

3. Shane SM: Conscious Sedation for Ambulatory Surgery. Baltimore University Park Press, (1983), p. 1.
 
 
 

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Signs of Safe Sedation Researched, Reviewed

Editor's Note: Adequate sedation and its associated physical signs have been discussed in recent issues of the Newsletter, and the resulting letters to the editor have provoked much interest in the topic. This article provides a more detailed discussion of the issue.

by G. B. Drummond, M.D.

In a conscious person, normal breathing takes place through the nose, because the soft palate directs the respired flow via the nose, and prevents flow through the mouth. (1) When normal subjects he in the supine position, nasal flow persists but the resistance of the upper airways is greater (2) and the retropalatal airway narrows (3) and the pharyngeal cross-sectional area is reduced. (4)

The upper airway, between the posterior nose and the larynx, is a flexible collapsible tube. The upper airway muscles act to maintain its patency, reducing its resistance and preventing collapse. The patency of the upper airway is normally maintained by activity of muscles such as genioglossus and sternohyoid, which act to dilate and thus decrease the resistance and collapsibility of the airway. (5-8) During normal sleep the resistance of the region of the soft palate increases considerably, and becomes exaggerated at greater flows, suggesting that collapse may be taking place. (9) Permutt and his colleagues suggest that this part of the airway is like a Starling resistor, in which collapse will occur if the resistance of the upstream segment of the airway is increased, so that flow is not related to the pressures downstream from this point. (10) If the resistance of the retropalatal airway increases, then collapse may occur in the downstream pharynx during inspiration.

In the awake state, the upper airway muscles act to maintain upper airway patency. They become active before the onset of inspiratory flow (11) and can be reflexly activated by decreases in airway pressure. (12) In the supine position, although airway dimensions are reduced, there is an increase in airway muscle activity (4,13) which is probably a response to the increase in airway resistance. A similar increase in activity is found when airway caliber is reduced by a decrease in end-expiratory lung volume. (14) Upper airway patency in sleeping humans is impaired by anaesthesia of the airway. (15,16)

Changes similar to those that occur during sleep are also seen after drug administration. Airway resistance, both in the nasopharynx and in the oropharynx, is increased in volunteers after alcohol ingestion (17) and airway resistance is increased after administration of midazolam. (18) Even very mild sedation with thiopentone, insufficient to abolish the nasal route of respiration, can impair the ability of humans to alter the route of respiration from nose to mouth if the nose is occluded. (19) Incremental doses of thiopentone cause a progressive reduction in airway muscle activity. (20) Although airway obstruction may result in reflex activation of the muscles, the increased activity is generally unable to overcome the obstruction. (20) Increasing doses of anesthetics appear to reduce activity of the upper airway nerves and muscles more profoundly than the diaphragm (21,22) and this action appears to be mediated by GABA. (23)

Consequently, agents such as the benzodiazepines would be expected to have profound effects on the airway, as indeed they do. (18) Evidence of the change of respiration from the nasal to the oral route, as shown by the movement of the relaxed lips [the 'pouf' sign suggested as indicating 'adequate' sedation], described by Dr. Shea (APSF Newsletter, Spring 1994), indicates that the soft palate has started to relax: airway resistance is likely to be greater. If resistance is increased, airway obstruction may occur through the Starling resistor phenomenon, with pharyngeal collapse. The problem may be exaggerated if the sedation is sufficient to result in the patient falling asleep, since this also increases airway resistance; and by the lips becoming drawn in on inspiration, since this yet again increases the airway resistance.

Drawing in of the lips during inspiration, and a puffing out on expiration, is a sign of excessive sedation, and a warning of impending episodes of airway obstruction as a result of loss of tissue/muscle tone and dynamic airway collapse. It is a "bad sign' (for the patients safety).

Dr. Drummond is Senior Lecturer, Department of Anaesthetics, The University of Edinburgh, Edinburgh, Scotland.

References

1. Rodenstein DO, Stanescu DC. Soft palate and oronasal breathing in humans. journal of Applied Physiology 1984; 57:651-657.

2. Anch AM, Remmers JE, Bunce H. Supraglottic airway resistance in normal subjects and patients with occlusive sleep apnea. Journal of Applied Physiology 1982, 53: 1158-1163.

3. Yildirim N, Fitzpatrick MF, Whyte KF, Jalleh R, Wightman AJA, Douglas NJ. The effect of posture on upper airway dimensions in normal subjects and in patients with the sleep apnea/hypopnea syndrome. Am Rev Respir Dis 1991 ; 144: 845-847.

4. Fouke JM, Strohl KP. Effect of position and lung volume on upper airway geometry. Journal of Applied Physiology 1987; 63:375-380.

5. van Lunteren E, Haxhiu MA, Cherniack NS. Relationship between upper airway volume and hyoid muscle length. journal of Applied Physiology 1987,63:1443-1449.

6. Brouillette RT, Thach BT. A neuromuscular mechanism maintaining extrathoracic airway patency. Journal of Applied Physiology 1979; 46: 772-779.

7. Fouke JM, Teeter JP, Strohl KP. Pressure-volume behavior of the upper airway. Journal of Applied Physiology 1986; 61: 912-918.

8. Odeh M, Schnall R, Gavriely N, Oliven A. Effect of upper airway muscle contraction on supraglottic resistance and stability. Respir Physiol 1993,92:139-150.

9. Hudgel DW, Hendricks C. Palate and Hypopharynx-sites of inspiratory narrowing of the upper airway during sleep. Am Rev Respir Dis 1988; 138:1542-1547.

10. Smith PL, Wise RA, Gold AR, Schwartz a Permutt S. Upper airway pressure-flow relationships in obstructive sleep apnea. Journal of Applied Physiology 1988; 64:789-795.

11. Strohl KP, Hensley MS, Hallett M, Saunders NA, Ingram RJ. Activation of upper airway muscles before onset of inspiration in normal humans. journal of Applied Physiology 1980; 49: 638-642.

12. Mathew OP. Upper airway negative pressure effects on inspiratory activity of upper airway muscles. journal of Applied Physiology 1984,56:500-505.

13. Douglas NJ, Jan MA, Yildirim N, Warren PM, Drummond GB. Effect of posture and breathing route on genioglossal electromyogram activity in normal subjects and in patients with the sleep apnea/hypopnea syndrome. American Review of Respiratory Disease 1993; 148:1341-1345.

14. Aronson RM, Carley DW, Onal E, Wilborn J, Lopata M. Upper airway muscle-activity and the thoracic volume dependence of upper airway-resistance. Journal of Applied Physiology 1991; 70:430-438.

15. McNicholas WT, Coffey M, McDonnell T, O'Regan R, Fitzgerald MX. Upper airway obstruction during sleep in normal subjects after selective topical oropharyngeal anesthesia. Am Rev Respir Dis 1987; 135:1316-1319.

16. DeWeese EL, Sullivan TY. Effects of upper airway anesthesia on upper airway patency during sleep. Journal of Applied Physiology 1988; 64:1346-1353.

17. Robinson RW, White DP, Zwilhch CW. Moderate alcohol ingestion increases upper airway resistance in normal subjects. Am Rev Respir Dis 1985; 132:1238-1241.

18. Montravers P, Diureuil B, Desmonts JM. Effects of I.V. midazolam on upper airway resistance. British Journal of Anaesthesia 1992; 68:27-31.

19. Nishino T, Kochi T. Effects of sedation produced by thiopentone on responses to nasal occlusion in female adults. British journal of Anaesthesia 1993; 71: 38&392.

20. Drummond GB. Influence of thiopentone on upper airway muscles. British journal of Anaesthesia 1989; 63: 12-21.

21. Hwang J, St.john WM, Bartlett D. Respiratory related hypoglossal nerve activity: influence of anesthetics. Journal of Applied Physiology 1983 55:785-792.

22. Ochiai R, Guthrie RD, Motoyama EK. Differential sensitivity to halothane anesthesia of the genioglossus, intercostals, and diaphragm in kittens. Anesthesia and Analgesia 1992; 74: 338-344.

23. Haxhiu MA, Mitra J, van Lunteren E, Prabhakar N, Bruce EN, Cherniack NS. Responses of hypoglossal and phrenic nerves to decreased respiratory drive in cats. Respiration 1986; 50:130-138.

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In My Experience:  Non-Cardiogenic Pulmonary Edema After Difficult Intubation

by James Kie-Chul Ohn, M.D.

Non-cardiogenic pulmonary edema associated with acute airway obstruction in an adult age group appears to be very rare. (1) Non-cardiogenic pulmonary edema has been described in pediatric age groups who had croup and epiglottitis (2) laryngospasm at the end of anesthesia, (3) and succinylcholine before induction of anesthesia.

We observed acute non-cardiogenic pulmonary edema on awakening from anesthesia in an adult whose trachea was intubated with difficulty in the beginning of anesthesia.

Case Report

A 57-year-old man was scheduled for right colon resection. He was found to have a cecal mass with some hemorrhage. The patient was 6 feet tall and weighed 200 pounds. His past medical history was unremarkable. He had no previous surgery or anesthesia. Physical examination did not reveal any abnormalities. Electrolytes were within normal limits. Hemoglobin was 14.5 gm/dl and hematocrit was 44. Chest x-ray was normal. EKG showed nonspecific ST-T changes. The patient was premedicated with 50 mg of mephedrine, 75 mg of pentobarbital and 0.4 mg of atropine one hour before the anesthesia started. The anesthesia was induced with 400 sodium thiopental, and 100 mg of succinylcholine was given to facilitate intubation.

However, the larynx was not able to be visualized because of its extreme anterior location. The patient was ventilated with 100% 02 and 2% of enflurane was administered. After a few trials with Macintosh and Miller's blade, it was decided to bring spontaneous breathing back to perform bend nasal intubation. However, severe laryngospasm was encountered and succinylcholine had to be given to break the spasm. This was attempted twice. Luckily, the third anesthesiologist was able to intubate the trachea by making a hockey stick shape with the stylet inserted to the endotracheal tube. The procedure took an hour using 600 mg of sodium thiopental and 260 mg of succinylcholine. Blood pressures were 160-170/90-110 and pulse rates were 100130/min. Mask ventilation was moderately difficult.

A few minutes after intubation, mild cyanosis in finger tips was observed and rales were heard on both lung fields. Very little white secretions were auctioned and lungs became clear as the anesthesia was deepened. Cyanosis in the finger tips disappeared. One thousand ccs of lactated Ringer's with 5% dextrose solution was given during that time. He had been NPO since midnight and anesthesia was started at noon. The anesthesia was maintained with 1% of enflurane/N20/02 and fentanyl. Pancuronium was used for muscle relaxation. He was mechanically ventilated with tidal volume 800 ml and rate 10/min. Inspiratory pressure was 28 cmH20. Blood pressure was maintained 100120\60-80 and pulse rate was 70-100/min. Total fluid given was 2,300 ml and estimated blood loss was 500 ml. The operation lasted three and a half hours from the beginning of anesthesia. Pancuronium was reversed with 10 mg of pyridostigmine and 1.0 mg of atropine and spontaneous breathing was resumed.

The patient was brought to recovery room and put on T-piece. Upon awakening, he was bucking on the endotracheal tube and bringing up pinkish frothy material through the tube. He was cyanotic, but awake and following verbal command. Blood pressure was 170/90, pulse rate 96/min. Coarse rales were heard on both lung fields. ABC's were pH 7.32, P02 48, PCO2 46 on T-piece with 10/min. 100% O@. Chest x-ray showed widespread alveolar densities in a butterfly distribution in both perihilar regions. The heart size was normal. EKG did not reveal any evidence of ischemia or infarction. Furosemide and morphine sulfate were given and he was mechanically ventilated. In 24 hours, pulmonary edema was completely resolved and he was transferred to a regular floor from ICU. Serial EKG and cardiac enzymes did not show any abnormal changes.

Discussion

Inspiratory efforts against closed glottis, hypoxia, difficult intubation under light anesthesia and awakening from anesthesia might have contributed to leakage of fluid to alveoli. All of these are interrelated to cause imbalance in Starling forces. The forces tending to move fluid outward are mean capillary pressure, negative interstitial pressure and interstitial fluid colloid osmotic pressure. Plasma colloid osmotic pressure holds fluid inward. Net effect results in slightly more outward forces than inward. It is balanced by fluid return to the circulation through the lymphatics. Difficult intubation under light anesthesia stimulates the sympathetic nervous system. Release of catecholamines causes peripheral vascular constriction which shifts systemic blood to pulmonary circulation. Emergence from anesthesia may increase catecholamine release because of pain, hypothermia and shivering. Shift of blood volume to the pulmonary circulation causes an increase in capillary pressure which favors outward movement of fluid. Neurogenic pulmonary edema is often explained by this mechanism. (5) Hypoxia in alveoli is known to cause hypoxic pulmonary vasoconstriction which exerts favorably to minimize ventilation perfusion mismatches. Pulmonary arteriolar constriction increases pulmonary capillary pressure.

Systemic hypoxemia increases catecholamine release which may contribute to systemic vasoconstriction and shift of blood to pulmonary circulation. Thus, both alveolar hypoxia and hypoxemia can raise pulmonary capillary pressure and enforce outward fluid movement in Starling equilibrium.

Undue Pressure

Inspiration through a closed glottis may increase transpulmonary intrathoracic pressure gradient. Transmission of this pressure to peribronchial interstitial space becomes additive to outward fluid movement from the capillary. In other words, negative interstitial fluid pressure which normally exists is greatly enlarged. (3) A large intrathoracic subatmospheric pressure affects left ventricular function. (6) Increase in afterload, decrease in left ventricular volume and ejection fraction, and decrease in velocity of contraction were observed during inspiration against closed glottis. (6) These changes favor a rise in pulmonary blood volume and pulmonary capillary pressure which, in turn, leads to the transudation of the fluid from the capillary into the alveolus.

Endothelial Injury

Simple imbalance in Starling forces does not explain all facts of non-cardiogenic pulmonary edema. Physical capillary endothelial cell injury has been suggested as a mechanism of fluid leakage. (7) As vascular distending pressure is increased, the tangential stress developed in the walls of microvascular endothelial cells ultimately pulls open the intercellular junctions. It may explain higher edema fluid to serum protein ratio in noncardiogenic pulmonary edema than cardiogenic pulmonary edema. (8) Although the documented cases in which pulmonary vascular pressures were measured are rare, (9) transient rise of pulmonary capillary pressure during episodes of catecholamine release may cause this type of physical injury to endothelial cells. Normal or lower than normal pulmonary vascular pressures can be expected after the actual incident.(1) The injury done by this mechanism appears to be reversible by supportive therapy in a relatively short period of time (1,3,4) Intramuscular succinylcholine administered to unanesthetized infants was associated with non-cardiogenic pulmonary edema. (2) Succinylcholine to our patient had a doubtful effect on pulmonary edema. Frightening due to paralysis while being awake might have increased catecholamine release, Repeated laryngoscopies to intubate the trachea in the patient under inadequate anesthesia might have increased catecholamine release which could lead to systemic vasoconstriction and shift of blood to pulmonary capillaries. Laryngospasm occurred twice on resuming spontaneous breathing to attempt blind nasal intubation. It resulted in hypoxia and excessive transpulmonary intrathoracic pressure gradient: both increased pulmonary capillary pressure and the latter causes more negative interstitial pressure. By the time endotracheal intubation was accomplished, stretched pores between capillary endothelial cells had perhaps been formed and leakage of fluid into alveoli already started. This may explain initial cyanosis and rales in the chest. Controlled ventilation and deepening of anesthesia by enflurane must have halted progression.

Fluid Leak

Upon awakening from anesthesia in the recovery room, negative pressure in interstitial space created by spontaneous breathing and catecholamine release by pain and shivering set up favorable conditions to move capillary fluid through already physically injured membrane into alveolus. This could explain the event in the recovery room.

Non-cardiogenic pulmonary edema associated with difficult intubation in an adult is rare, but it can be reasonably explained by the mechanism involved in neurogenic and pulmonary edema occurring in acute airway obstruction in the pediatric age group. Awareness of this complication by anesthesiologists should lead to prompt diagnosis and treatment. High edema fluid to serum protein ratio (0.84) (7) and normal or lower pulmonary capillary wedge pressure should confirm the diagnosis. (1) Deep anesthesia and maintenance of good airway are thought to be the best ways to prevent this complication when difficult intubation is encountered. The treatment consists of mechanical ventilation with PEEP or CPAP and oxygen. Diuretics may or may not be needed. Measurement of the pulmonary capillary wedge pressure should best guide safe administration of diuretics and fluid.

Dr. Ohn is Chief of Anesthesia at Landmark Medical Center, North Smithfield, RI.

References

1. Gardaz JP, Foster A, Suter PM. Edeme pulmonaire aigu fuminant sans defaillance cardioque en fin d'anesthsie. Cana Anaesth Soc J 1979; 26: 34-37.

2. Cook DR, Westman HR, Rosenfeld L, Hemershot RJ. Pulmonary edema in infants: possible association with intramuscular succinylcholine. Anesthesia and Analgesia 1981; 6: 220-223.

3. Lee Kwt, Downer JJ. Pulmonary edema secondary to laryngospasm in children. Anesthesiology 1983; 59:347349.

4. Travis KW, Todres ID, Shannon DC. Pulmonary edema associated with croup and epiglottitis. Pediatrics 1977; 59: 695-698.

5. Robin ED, Theodore J. Pathogenesis of neurogenic pulmonary edema. Lancet 1975; 2:749-751.

6. Buda AJ, Pinsky MR, Ingels NB. Effects of intrathoracic pressure on left ventricular performance. N Engl J Med 1979; 301: 453459.

7. Staub NC. The pathogenesis of pulmonary edema. Prog Cardio Vac Dis 1980,23:53.

8. Sprung CL et al. The spectrum of pulmonary edema: Differentiation of cardiogenic, intermediate, and non-cardiogenic forms of pulmonary edema. Am Rev Respir Dis 1981; 124:718.

9. Wary Np, Nicotra MB. Pathogenesis of neurogenic pulmonary edema. Am Rev Respir Dis 1978,118: 783-786.
 

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APSF Committee Update

As follow-up to the usual year-end publication of the officers, directors, and committee members of the APSF, for clarity, the correct list of members of the Committee of Technology is:

Joseph W. Pepper, Ph.D., Chairman BOC Health Care, Inc.

Vincent Buffano Baxter Healthcare Corp.

Peter Cartensen FDA

Patrick A. Foster, M.D. Hershey Medical Center

Julian Goldman, M.D. Denver, CO

Ervin Moss, M.D. Verona, NJ

Helmut Thiemann North American Drager, Inc.

Also, the name of Frederick A. Robertson, M.D., Marquette Electronics, should be added to the Committee on Scientific Evaluation.

Finally, it should be noted that APSF Director Frederick W. Cheney, M.D., is from the University of Washington School of Medicine, Seattle.
 

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Parenteral Medication Recommendations to be Distributed

In recent years, there has been a trend toward increased use of intravenous anesthetic agents in the operating room and for sedation of ventilated patients in the intensive care unit. Since outbreaks of infection have been associated with intravenous medications, an understanding of appropriate aseptic technique is necessary for their use.

A booklet entitled, 'Recommendations for Handling Parenteral Medications Used for Anesthesia or Sedation" and an accompanying poster have been prepared and will be distributed to members of the Anesthesia Patient Safety Foundation through a grant provided by Zeneca Pharmaceuticals. The recommendations are derived from current infection control guidelines and published studies.

As the medical community is faced with increasing production and economic pressures that could compromise safety, it is more crucial than ever that proper infection control practice be maintained.

For more information, contact Arnold Berry, M.D., Professor of Anesthesiology; Emory University School of Medicine; 1364 Clifton Road, N.E.; Atlanta, GA 30322; (404) 778-3937.

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Editorial:  Recurrent Issues Prompt Call for Continued Effort

Recently two anesthesia patient safety considerations have resurfaced.

The first has appeared in "Letters to the Editor" column in this Newsletter concerning anesthesia practitioners reading in the operating room while administering anesthetics. Certainly an anesthesiologist of my vintage, forty years of practice, rigidly proscribes reading during a case. I concur with the thoughtful letters in the negative found in the Spring APSF Newsletter.

I will point out, however, that Nik Gravenstein, M.D., one of the wisest persons I have ever known, does not completely agree. In his view, reading about the actual case under way, in order to deal with management problems, is reasonable. This would include textbooks, current articles, and anesthesia information systems. He believes that such reading may well lead to better anesthesia outcomes. Certainly he does not approve of anesthesia providers reading extraneous materials such as newspapers, financial reports, and novels.

The other issue that I thought had disappeared, following the establishment of the ASA Standards for Basic Anesthetic Monitoring several years ago, is the failure of the anesthesia provider to remain full time in the operating room continuously throughout the case taking care of the patient. Once more, it has come to my attention that in some practices, unfortunately, the anesthesia practitioner goes out of the operating room, leaving an anesthetized patient unattended, Anecdotal evidence suggests that in the last year, at least two patients have suffered cardiac arrest while the anesthesiologist was out of the room. I have been told that such situations may result in criminal prosecution of the practitioners.

Let us all work to continue the march forward of anesthesia patient safety in all arenas, including these two in particular.

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

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Newsletter Editorial Policy Adopted

The following is an editorial policy adopted by the APSF Board of Directors at its October 1994 meeting, as proposed by the Anesthesia Patient Safety Foundation Newsletter Editor, John H. Eichhom, M.D.

At its meeting in October, the Executive Committee of the Anesthesia Patient Safety Foundation considered issues regarding the publication of articles in the APSF Newsletter which contain original research data not yet subjected to peer review. The Executive Committee makes the following statement:

o Editorial decisions about the publication of submitted materials in the APSF Newsletter rest with the Editor, in consultation with the Newsletter Editorial Board.

o The presence of original research data in an article submitted to the Newsletter does NOT in and of itself prevent that manuscript from being published in whole or in part in the APSF Newsletter. The decision on whether to publish any manuscript is based on content, quality of the writing, timeliness, and apparent interest to the readers of the Newsletter.

o Articles containing original research data should be clearly identified as such in the Newsletter. For these articles (as well as others at the discretion of the Editor), there should be a special explanatory note reminding the reader that the material represents the statements of the named author(s) and that the article has NOT undergone peer review of its scientific content. Furthermore, the reader again should be reminded that the article does not necessarily represent the opinion of the Editor, the Editorial Board, or of the Anesthesia Patient Safety Foundation officers, directors, or members.

o Recipients of the Newsletter are enthusiastically encouraged to submit letters or articles critiquing or affirming authors' statements contained in articles published in the Newsletter.
 

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Reading Debate Yields Survey Facts, Strongly Opposing Reader Opinions

Survey of 97 Residencies Shows Few OK OR Reading

by William 0. Witt, M.D.

In an attempt to determine whether there was national policy in educational programs regarding the practice of reading during the maintenance phase of the administration of 'routine" anesthetics, all 115 members of the Society of Academic Anesthesia Chairs were surveyed by mail. 97 complete questionnaires were returned. Of these 97, 70 report policy that forbids reading as described, and 23 institutions allow reading to occur. Breaking down these 23 that indicated that they allow reading, nine of them allow, but 'discourage strongly,' one allows only in open heart cases while on bypass (and then only material related to the case at hand) and three allow materials to be read that are relevant to the current case at hand only.

This leaves 10 programs that indicated that they allow reading as indicated with no limitations thereon, for a frequency of 10%. Thus, 90% of academic programs either forbid, strongly discourage, or otherwise limit reading in the OR during anesthetics.

Dr. Witt is Professor and Chairman of Anesthesiology at the University of Kentucky, Lexington.
 

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Memorial Contributions Welcome

The Anesthesia Patient Safety Foundation is pleased to announce that contributions are now being received to honor or pay tribute to some special person on the occasion of a memorial or such special events as retirement, honors achieved, etc. Checks in any amount should be accompanied by the name of the honoree and (if appropriate) the occasion honored, made payable to the Anesthesia Patient Safety Foundation, and mailed to:

Anesthesia Patient Safety Foundation

520 N. Northwest Highway

Park Ridge, IL 60068-2573

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APSF Corporate Donors

Grand Patrons

American Society of Anesthesiologists

Burroughs Wellcome Co.

Cerenex, a Division of Glaxo, Inc.

The Dryden Fund Ohmeda, Inc.

Preferred Physicians Mutual Risk Retention Group

Puritan-Bennett Corporation

Zeneca Pharmaceuticals Group (ICI)

Patrons

Abbott Laboratories Nellcor, Inc.

Organon, Inc.

Sustaining Members

Baxter Healthcare Corporation

Becton Dickinson Critikon

Datex Medical instrumentation, Inc.

Hewlett Packard Company

Mallinckrodt Medical, Inc.

Marquette Electronics, Inc.

Medical Inter-insurance Exchange

North American Drager

Sponsoring Members

J. Jeffrey Andrews, M.D.

Anesthesiologists' Professional Assurance Co.

Arkive Information Systems, Inc.

Aspect Medical Systems

Augustine Medical, Inc.

Beth Israel (MA) Anesthesia Foundation

Biennial Western Conference of Anesthesiology

CAE Link Corporation

Datascope Corporation

Grace Container Products

Janssen Pharmaceutica

King Systems Corporation Loral, Inc.

Medical Gas Management, Inc.

Miles, Inc., Pharmaceuticals

Minneapolis Anesthesia Associates

Pain Net, Inc.

Southeast Anesthesia Associates, P.A.

Texas Medical Liability Trust

University of Texas Medical Center

Wisconsin Society of Anesthesiologists

Corporate Level Members

Anesoft, Inc.

Arizona Society of Anesthesiologists

Arrow International

Boeringer Laboratories, Inc.

Frederick W. Cheney, M.D.

Independence Anesthesia

Iowa Society of Anesthesiologists

Mississippi Society of Anesthesiologists

Pall Biomedical Products Company

Pennsylvania Medical Society Liability Ins. Co.

Texas Society of Anesthesiologists

Contributions to APSF received before June 15,1995, will be acknowledged in the next four issues, beginning with Summer 1995. Contributions received after that date will be acknowledged in the four issues beginning with the Fall 1995 Newsletter.
 

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Notes

David J. Birnbach, M.D., Director of Obstetric Anesthesiology and Resident Education at St. Luke's-Roosevelt Hospital Center in New York City, has been awarded the APSF/Dryden Research Grant Pr 1995. The title of his research project is 'Skin disinfection prior to initiation of epidural anesthesia: a microbiologic assessment of a commonly utilized method of skin disinfection and evaluation of a new means of antisepsis." Dr. Birnbach is also an Assistant Professor of Anesthesiology in Obstetrics and Gynecology at the College of Physicians and Surgeons of Columbia University.

The Gale E. Dryden, M.D., Research Fund was established in 1993 within the Anesthesia Patient Safety Foundation to honor Dr. Dryden and to support research on anesthesia-related nosocomial infections.
 

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, 1995

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.

Newsletter Editorial Board:

John H. Eichhom, M.D., Editor; David E. L&-s, M.D. and Gerald L. Zeitlin, M.D., Associate Editors; Stanley J. Aukburg, M.D., Jan Ehrenwerth, M.D., Ralph A. Epstein, M.D, Nancy Gondinger, CRNA, Robert C. Morell, M.D. Jeffrey S. Vender, M. D.

Editorial Assistance Nola Gibson, Ph.D.

Address all general, membership, and subscription correspondence to:

Administrator

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. Eichhorn, M.D.

Editor, APSF Newsletter

Department of Anesthesiology

University of Mississippi Medical Center

2500 North State Street

Jackson, MS 392164505
 

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