Volume 7, No. 2, 13-24 Summer 1992
Table of Contents

Risk Analysis Model Targets Anesthesia Incidents
Letters to the Editor
Editorial response: A Surgeon's View
Is Competency with our Equipment a Safety Problem?
APSF Committee on Education and Training:
"Medic Alert" System for Difficult Airway is Subject of National Communication Effort
ASA Safety Tapes Add "Difficult Airway II"
Foreign Correspondence: Day Surgery Recovery: When Is It Safe to Discharge to Home
We Could Not Even Recognize Perfection
Event Case Reports Sought

Risk Analysis Model Targets Anesthesia Incidents

Study of Accidents Identifies Critical Factors, Should Improve Safety

by M. Elisabeth Pate'-Cornell, Ph.D.

In a study currently under way at Stanford University, records and analyses of past anesthesia critical incidents (and the opinions of experts) are used to identify and assess the root causes of anesthesia problems. Most of these problems (but not all of them) come from human errors, some of which can be directly linked to management factors. The objective of this work is to identify risk reduction measures and to set priorities by assessing the benefits of each. To do this, the study started with the development and extension of a probabilistic risk analysis (PRA) model for anesthesia patients.

Risk analysis models are based on the identification of accident sequences and on the computation of their probabilities based on the probabilities of the basic events, including both component failures and operator errors. The PRA techniques were developed mostly for engineering systems (originally, nuclear power plants). The objectives of such analyses are to identify and correct the -'weak spots' and to allocate scarce resources for maximal risk reduction. Because they were developed by engineers, these studies tend to focus on the reliability of the hardware and to point primarily to technical measures of risk management; for example, adding a redundancy behind a critical component or reinforcing a key element (structural or procedural). Yet, the probabilities of failure of the components are often influenced by human decisions and actions that take place during the different phases of the system's life (e.g., design, construction, or operation). Furthermore, these decisions and actions are often grounded, in turn, in the organization's structure and culture which determines: (1) the information flow, (2) the rewards and incentives, and (3) the resource constraints under which the 'actors' must operate. These organizational factors can therefore become the root causes of potential accidents. As part of a risk management strategy, it is sometimes more effective to modify these organizational factors than to modify the hardware.

'Management' Factors Into System Failures

Management factors are only implicitly included in classical risk analysis models. A few years ago, Stanford researchers began working toward an extension of PRA models to include management issues. The approach is to start with an analysis of the physical system because in the final analysis, for an accident to occur, one of the various failure modes must occur. The first step thus is a probabilistic risk analysis of how likely such failures might be. Then, for each of the basic events of each accident sequence (i.e., failures of components or operator errors), the human decisions and actions which influence its probability are identified. Finally, researchers look for the organizational roots of each decision and action what features of the 'culture' of the situation might have influenced each event.

In earlier research, this approach was applied to the case of offshore oil drilling platforms. That study found that about 95% of the failure probability is associated with some form of reduction of the system's function by some type of error (or combination of errors) in design, construction, and/or operation. Only 5% of the risk for failure of these platforms corresponds to the classical case of huge waves in the sea damaging a well designed, constructed, and operated platform. The study also found that an external design review by a certified verifying authority can reduce the probability of platform failure by 20% at a hundredth of the cost of built-in technical measures bringing the same benefit.

This method was also applied to the thermal protection (heat shield) system of the space shuttle. First, the potential contribution of each black tile in each location on the orbiter's surface to the overall probability of an accident was computed. The inputs of this model were linked to the maintenance operations for the tiles and to the management factors that affect the quality of the file work. This study found that 85% of the risk to the shuttle was attributable to only 15% of the tiles. Researchers then showed that selective inspection to find the poorly bonded tiles in these most critical zones could considerably reduce the overall costs while preserving safety. They also showed that careful inspection of the insulation of the external tank and the solid rocket boosters (that could fall off and hit the tiles in the most critical zones) could also reduce considerably the overall risk of losing a shuttle due to a hole in the orbiter's skin. Key organizational factors identified in this study include the fragmentation of the NASA and some procedures of personnel management that determine the quality of the maintenance work.

In these previous studies, several general observations were made. Many organizations seem to have difficulties in the management of resource constraints (e.g., time or budget pressures). Under such pressures, people tend to cut comers, which may weaken the system in a way that may or may not be understood at the time. They also have difficulties managing the tradeoff between productivity and safety, often claiming that safety comes first but rewarding only productivity.

Productivity Vs. Safety

Organizations, and particularly successful ones, also have difficulties observing signals of deterioration, recognizing that something is going wrong, communicating the bad news and following up to correct problems. They have particular difficulties in communicating uncertainties, showing a tendency to optimism and distorting the message. Under these conditions, learning under uncertainty (particularly from 'near-misses') becomes difficult. Finally, organizations do not seem to perceive "structural" weaknesses that may cause organizational as well as technical failures: for example, dangerous couplings among components (common causes of failure), and lack of redundancy in the organization. Anesthesia delivery systems and anesthesia practice share some of these problems.

This work on management and system reliability and its application to the safety of offshore oil drilling platforms was published in Science in 1990 and attracted the attention of David Gaba, M.D. (Stanford Medical School). It appeared from conversations at that time that some of the problems which had been identified and analyzed for engineering systems existed in the field of anesthesia. A research proposal was submitted to the Anesthesia Patient Safety Foundation to do two things: (1) construct and quantify a probabilistic risk analysis model for the risk of patient death or brain damage associated with anesthesia practice, and (2) identify organizational factors that influence the input into this risk analysis model. -Whenever possible, the link between these factors and the corresponding variables will be quantified. The research started January 1, 1992. After four months, the model has been formulated, some coarse estimates of the contribution of each type of accident to the overall risk have been obtained, and some of the organizational factors that may affect the probability of each accident sequence have been identified.

This work has been based so far on: 1.) a review of the literature, 2.) a set of interviews with anesthesiologists, surgeons, operating room nurses, and lawyers, and 3.) the data gathered by Dr. William Runciman (Adelaide, Australia) on about 2,000 cases of incidents in anesthesia. The structure of this model was based in large part on conversations with Drs. David Gaba and Steven Howard of the Stanford Medical School. The goal of this study is to improve the management of anesthesia delivery in order to decrease the probability of accidents leading to death or brain damage. This research focuses on healthy patients in large urban western hospitals. The background risk is already low, involving less than one accident in 10,000 operations, and this research effort is looking for ways to make it still lower. Focusing on the anesthetist, the objective is to set priorities among specific safety measures based on the potential decrease of their contributions to the corresponding risk factors. The final analysis can thus be represented as an influence diagram showing the effects of management on the accident rate in anesthesia (Figure 1).

This risk analysis model is a causal, 'forward looking" analysis of the sequences of events that may lead to an accident. The key elements of this model are:

1. The initiating events (e.g., a tubing disconnect at the endotracheal tube connector).

2. The signals that appear following an initiator, either from monitoring devices or from the patient.

3. The observation of signals by the anesthetist.

4. The correct diagnosis of the problem.

5. The corrective actions that are taken at this stage.

6. The effectiveness of corrective actions.

Each of these steps involves a delay which is treated as a random variable. The sum of these random variables is the time elapsed between the problem's occurrence and possible corrective action. This total time and the appropriateness (effectiveness) of the corrective actions determine the patient's state at the end of the episode. Figure 2 is a flow diagram showing the sequence of events considered in this analysis.

The first task is to divide the initiating events into a set of exhaustive, mutually exclusive classes of scenarios. This classification of accident initiators must be specific enough to make the analysis meaningful, yet simple 'and inclusive enough to make it manageable. We identified five broad categories of accident initiators:

1. Failure of equipment (mechanical, electrical, chemical, etc.) mostly involving the delivery of oxygen to the patient. This class includes some big events like a massive mechanical failure or minor ones such as a twisted tube that impedes the gas flow. It also includes hypoxic gas mixture.

2. Failure of the breathing system including the following:

* Esophageal intubation

* Breathing tube disconnect, often due to moving the patient

* Overpressurization of the breathing system o Nonventilation

* Rebreathing of carbon dioxide

The boundaries between these first two categories (failure of equipment and failure of the breathing system) may become fuzzy. The first one involves clearly technical failures; the second includes mostly human errors on the scene.

Figure 1: An influence diagram for the analysis of the effects of management factors on the risk of accident in a specified system.


3. Drug errors

a. Incorrect dose (mostly overdose)

* Inhaled anesthetic (OD)

* Vasodilator (OD)

* Vasopressor (OD)

The subjectivity of the concept of overdose is understood and the opinions of experts are being used to identify situations that qualify as accident initiators.

b. Syringe or ampule swap

* Muscle relaxant reversal (instead of muscle relaxant)

* Muscle relaxant instead of reversal.

This type of error can be caused by an outright failure to read the label or a confusion between two labels that look alike, and such errors can be rooted in the stress and rush inherent to emergencies.

c. Allergic reaction

This one may or may not be predictable given the patient's history and the possibility of properly gathering that information when it is available.

4. De novo events

Events that occur by chance in the operating room include the following:

* Certain cardiac arrests

* Malignant hyperthermia

* Asthma attack

* Pneumothorax.

They are rare, rather specific, present clear signals, and in general, the anesthetists have been warned and trained to treat them even if they seldom occur (e.g., malignant hyperthermia).

5. Hemorrhages

This is a borderline case as far as anesthesia is concerned because it is generally caused by the surgeon. Yet, it is the anesthesiologist's responsibility to keep the patient alive and to provide the appropriate blood supply while the problem is being corrected. This implies, among other things, proper typing and crossing of the blood supply.

Based on the opinions of the involved experts, a coarse assessment of the base rates of each of these types of initiators given that an incident occurs is:

1. Failure of the equipment: = 0%

2. Failure of the breathing system: = 40%

3. Drug errors: = 45%

4. De Novo events: = 5%

5. Hemorrhages: = 10%

Clearly, these base rates depend on the type of surgery (for example, E.N.T. surgery is more likely to cause a hemorrhage than a knee cap operation); but as a first cut, they indicate that the dominant initiators are drug errors and failure of the breathing system.

Following the occurrence of an initiating event, the patient reacts to the incident and the anesthetist generally observes the signals and corrects the problem. Two systems thus evolve during the actual incident in parallel (and in conjunction):

1. The anesthesia system (anesthetist, helpers, and equipment).

2. The patient.

These two parallel evolutions are modeled using a dynamic Markov model characterized by the probability of state transitions per time unit. Therefore, the patient's states are defined as follows, for example, in the case of a tube disconnect incident:

* Healthy

* Hypoxemic

* Arrhythmia (or cardiac arrest)

* Brain damage or death.

The probability of transition from one patient state to another (i.e., the speed of deterioration) depends on the phase in which the anesthesia system is operating. For example, for a tube disconnect initiator:

* Phase 1, before the disconnection: no problem.

* Phase 2, between the disconnection and the problem correction: deterioration due to lack of oxygen.

* Phase 3, after correction (if it is done in time): recovery.

Figure 2: Structure of the mathematical model for the analysis of anesthesia accidents: general representation of an accident sequence.

Figure 3 shows the parallel evolution of the patient's state and the anesthesia system.

The data being used to quantify these probabilities, rates, etc. come basically from two sources: statistics and expert opinions. The main statistical source is the database gathered by Dr. Runciman. For about 2,000 incidents, he and his colleagues attempted to systematically record the causes and the outcomes of the problems. This data set is biased because it relies on voluntary reports; in particular, hospitals were given the option not to report if they feared legal problems. Other statistics can be used to correct the information of this database.

In addition to statistics, experts' opinions were gathered from a variety of sources including anesthetists, surgeons, operating room nurses, and lawyers. In the future, researchers will also talk to insurers and to patients or consumer groups. There has been developed a data sheet that represents, for each initiating event, the dynamics of the incident evolution (see Figure 4). In addition, they helped develop tables of relevant mean times elapsed for each interval between relevant events of accident sequences.

Calibrated Estimates of Risk

As in other studies of the same kind, statistical information and experts' opinion are used in parallel. Expert opinions and the analytical model allow researchers to compute the probability of each accident or incident scenario. They can then be grouped and coarse estimates of the probabilities of classes of scenarios can be computed. The statistics then provide a benchmark against which the validity of these estimates can be checked. If there is a significant discrepancy, researchers can then come back to the expert and re-calibrate some of the estimates. At this time, researchers are in the process of developing this quantitative analysis.

At the same time, they have gathered from experts a sense for organizational factors that may affect some of the probabilities of this model. It is understood that these factors may or may not be correctable in the near future for reasons that can range from the practical (both to the patient and the medical profession) to the economic. The benefits of addressing these issues, however, may be substantial.

1. The work schedule can be a source of problems. The stretch of time during which surgeons, anesthetists and residents are on call or on duty can be potentially very long. In some states, residents can be on their feet for 24 hours in a row (other states have set stricter time limits). Although in general, there are times to rest during that period, it is possible that a resident will be called to an emergency after 22 hours of work. Fatigue, steep deprivation, and stress at that stage cannot improve the ability of the anesthetist to observe signals of problems, find their causes and decide on appropriate corrective measures. The problem is compounded by the non-specificity of many of these signals, and also by the fact that an emergency at the end of a long work period often adds stress to the background fatigue.

Unclear Decisions

2. The decision to operate and whether or not it is wise to proceed as scheduled is not always clear cut. Information errors may occur and the surgeon or the anesthetist may not have critical data at the time of the decision. Incentives and production pressures may also tip the scale in borderline cases. If and when the surgeon and the anesthetist have different opinions, there are not always clear mechanisms to resolve the conflict and the decision may depend mostly on personalities and power. The surgeon in this circumstance may prevail.

3. The payment and compensation structure may compound this problem because it shapes the basic incentive system. In situations where compensation is based on the number and the type of cases, production pressures may be more severe than in cases where personnel are paid flat rates per unit time.

Who is "Captain"

4. Problems of conflict of authority may also exist in the operating room where a clear hierarchy may no longer exist. The surgeon was once the .captain of the ship.' For legal reasons, he or she can no longer be made responsible for the anesthesiologist's decisions. (Furthermore, surgeons are not necessarily trained and competent in anesthesiology.) From this duality of authority, conflicts have surfaced which, at least in one case, has led to the death of a patient while both sides were arguing about priorities. The smooth resolution of problems thus rests on the compatibility of personalities among the people involved. The culture of the operating room, however, has sometimes promoted the emergence of authoritarian and arrogant characters with ineffective interpersonal skills.

5. The screening and selection of anesthesiologists according to personalities, skills, reasoning capabilities and ability to handle crisis situations is thus critical. The problem is that there is no formal screening beyond the entrance to medical school. Informally, the 'probably incompetent' can be gently steered toward other fields of specialization. But that, too, is difficult since competence and understanding of the job may take a while to reveal themselves.

Figure 4: Structure of the data gathering process used in this study. (After Gaba and Howard)

6. The training of the anesthetists, for example in the use of a simulator, may be critical to ensure that they acquire 1.) the competence and skills in their domain and 2.) the ability to react fast under pressure in a crisis mode.

7. The presence of a backup for the anesthetist, who in a crisis situation can provide both assistance and a fresh look at an urgent diagnosis, may therefore also be critical. Although this backup is generally available in large hospitals, anesthesiologists and, in particular, residents may be reluctant to call for help for two reasons: overconfidence and fear of being judged incompetent. In other terms, it may be those who need help the most who are least likely to ask for it. In freestanding surgery centers, this backup help may simply not be available.

8. Detection of performance decline at mid-career and at the end of a doctor's career is an extremely difficult issue. There is no formal mechanism -in the absence of gross incompetence to force someone to retire when it is clear that he or she can no longer perform safely. The system seems to handle these cases informally by assigning easier cases to such people and providing informal assistance.

Provider Impairment

Still more complicated is the issue of mid-career performance decline due to drug abuse or alcoholism. Formal mechanisms involving confrontation of the individual and forced treatment are rarely used 1.) because they are painful for everyone and 2.) because they expose the confronters to legal actions. Informal mechanisms are not very effective because detecting and identifying the problem of drug or alcohol abuse is extremely difficult short of random testing. Yet, the presence of drugs as part of the working environment makes it tempting for some to use them for recreational purposes. Careful accounting by the nurses of the drug delivered and attention paid to the overprescription of a particular drug provide some clue but no guarantee that such a problem will be detected and addressed.


9. Mid-career reevaluation or recertification has been proposed (and resisted by a number of physicians). Techniques evolve, skills may decline, and some anesthetists may no longer be up to date and able to provide patients with the benefits of recent developments. Regular recertification similar to procedures of the airline industry can permit verification that physicians are able to perform their functions and could provide anesthetists an incentive to upgrade their technical skills.

10. Operating room procedures and environment dearly affect the safety of surgery. There is a constant tradeoff, as in many fields, between the sophistication of electronic equipment and the skills needed to use it properly. In particular, there is a tradeoff between the number of monitors and the frequency of false alarms that may distract the physician and/or cause him to turn off the system with potentially disastrous effects. A more subtle problem is that physicians trained exclusively in the use of such complex equipment may lose the basic skills and fundamental understanding that one needs to operate without them.

Yet, some procedures and equipment may be helpful in crisis situations. First and simplest, crisis management protocols and second, (and directly linked) computerized decision support system that may prevent oversights and guide the diagnosis can be useful.


11. Options have been suggested which are desirable for some people and elected by others as too cumbersome or expensive. First, the option to specialize in particular types of operations (e.g., cardiac or pediatric surgery) has been proposed and is already in place in some organizations; or the option to simply stay away from a particular type of cases about which one feels nervous or uncomfortable may be provided. The downside includes the multiplication of specialties with resulting cost increases and the loss of skills which may be needed in emergencies.

The second option is the possibility of forming surgeon-anesthetist teams. In a profession where egos can be large and delicate, the benefits are clear in cases of open personality conflicts that can pose a hazard to the patients. On the other hand, this proposal would create additional scheduling problems and an increase in cost.

Several management measures can therefore be envisioned to address these problems including: improvement of the mechanism of decision to operate, shorter working schedules (e.g., 12 or 16 hr. shifts), procedures for selection and screening, systematic simulator training, recertification, backup for the anesthetist, stringent monitoring of alcohol and drugs by random checks, and options of specialization and formation of surgeon-anesthetist teams. Each of these measures involves costs but may also provide substantial benefits in the form of increased patient safety.

These researchers are now in the process of linking this risk analysis model to organizational factors, by gathering the following information:

1. Which variables are affected by each factor initiating event and probabilities of detection and correction within given time frames)?

2. By how much can one expect these parameters to vary if one modifies the management factors and with what effect on the overall risk?

The risk analysis model thus provides a calibration tool by yielding the prior contribution of each parameter to the risk.

The problem of safety of anesthesia has often been compared to that of airline safety. Indeed, the two critical phases of takeoff and landing with long, uneventful periods in between, during which crises may nonetheless occur, make the two situations similar. The management problems may be similar as well, and one may learn from the airline industry about the benefits of screening, recertification, and monitoring for substance abuse.

A key issue is whether the medical profession is willing to police itself, or if economic and political pressures will force the responsibility on the managing institutions.

Dr. Elisabeth Pate'-Cornell is Professor of Industrial Engineering and Engineering Management at Stanford University. Her specialty is risk analysis, and her recent research has focused on the linkage between organizational factors and the risk of accidents in complex technical systems.

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Letters to the Editor

Supplemental O2 for MAC Cases: Is it Valuable? Is it a Hazard?

To the Editor

I need advice on addressing what I feel is an unsafe practice in our operating room regarding supplemental oxygen to patients having cataract extraction utilizing M.A.C.

Currently the patient has applied NIBP, EKG, pulse oximeter, and I additionally add a sternal notch stethoscope. A large curved perforated aluminum bar (placed in the traditional 'ether screen" location) with 8-10 L/M oxygen flowing through it and out near the patient's head is installed, the patient is sedated minimally, and the retrobulbar block is administered by the surgeon. The patient is then draped with disposable draping material with the long body sheet tented up onto one IV poll to allow visualization of the patient's lower face and to allow escape of accumulated supplemental oxygen and exhaled carbon dioxide.

My concerns are:

1. Sedating a geriatric patient without nasal oxygen in place

2. Collection of such a large volume of oxygen under the drapes

a. Does not help oxygenation much (minimally raises the SaO2 per pulse oximeter readings)

b. Creates a potential fire hazard

c. May promote rebreathing of the exhaled carbon dioxide which is not being properly vented away from the patient?

3. Potential fire hazard

a. Cautery is used (battery operated, but still hot enough to bum the drape material)

b. Disposable draping material is used

c. High flow oxygen is accumulating under the drapes

Fires in the OR are reported and the dangers are worse with the unregulated flammability of disposable drapes. I even saw a lengthy article on the subject in a professional firefighting journal.

I would appreciate any information to provide a safer anesthesia experience for our patients.

Doris M. Penndorf, CRNA Winsted, CT

Editor's Note: Readers are invited to respond and replies will be considered for publication in this column.

What is Value of F102 Monitoring Compared to Pulse Oximetry?

To the Editor

Regulations in some countries, such as ours (FRG), mandate the monitoring of inspiratory oxygen concentration (F'02) in the anesthesia breathing system (A.B.S). In my opinion, pulse oximetry (P.O.) adds more to patient safety than F102-monitoring ever could; therefore, I would like to ask two questions:

1. Would it diminish patient safety if, instead of also monitoring F102, arterial oxygen saturation alone were monitored by P.O.? Or would that even enhance patient safety, especially when using an 02/N20-mixer Which provides, under optical control via flowmeters, at least 21 volume percent 02 under all conditions? (1)

2. If, never the less, the monitoring of oxygen concentration in the A.B.S. is considered essential in spite of P.O., why in the inspiratory and not in the expiratory limb (at least in circle systems)? In my experience monitoring FE02, instead of F102, gives more information, e.g. on the effect of preoxygenation or indirectly on N20-washout at the end of anesthesia and is not less safe.

My first question has a financial background. Actually we, according to regulations, must buy a FIO2-monitor for every anesthesia machine. Due to this, our budget does not allow us to buy enough pulse oximeters. With respect to the fact that the sensors in the oxygen monitors used in our institution need replacing roughly once a year, oxygen monitors are nearly as expensive as P.O., but in my opinion, less useful. I would prefer to spend the money on P.O. Is this, from a scientific/practical point of view, reasonable? (I do not expect legal consequences to be considered).

I would appreciate very much if a discussion on these questions could take place.

Jurgen Link

Klinikum Steglitz der FU Berlin Federal Republic of Germany


1. Heath, J.R., Anderson, M.M., Nunn, J.F. Performance of quantiflex monitored dial mixer. Br. 1. Anaesth. 1973; 45:216

Reader Scorns Standards, Calls for Use of Anesthetists' Noses, Lungs, Ears as Anesthesia Monitors

To the Editor

I believe that there are areas in the USA and certainly many, many areas elsewhere in the world where the ASA (and other) Standards and Guidelines are, because of financial constraints, difficult or impossible to comply with.

In South Africa, one of the unwanted outcomes of Guidelines is the automatic assumption by legal authorities that failure to observe them is ipso facto evidence of negligence. In this country, such assumptions by the courts will lead automatically to disciplinary proceedings. But about half of our medical staff work in state-funded facilities and cannot always purchase what they wish to use. This is a disadvantage which is in no way due to their own negligence although they may suffer considerably as a consequence of the failure to adhere to Guidelines or Standards promulgated by our own Society of Anesthesiologists.

I don't want to debate that issue in the Newsletter, but I do think that it is appropriate to draw attention to inexpensive and reliable alternatives to some of the gadgetry which the Guidelines emphasize and which, I believe, could well be incorporated AS ALTERNATIVES WHEN CIRCUMSTANCES DICTATE, even in the ASA Standards. We overlook many of the gifts with which Nature has endowed us and that could be called a cardinal sin. To me it is certainly negligence.

So I do hope that you will be able to publish my small contribution.

Professor Ross Holland's report of a 'Wrong Gas" incident prompts me to remind readers of a very old, very reliable, very simple and very cheap method of making certain that such accidents do not occur.

In the distant past, before technology provided oxygen and carbon dioxide analyzers, it was routine practice for the anesthesiologist to use-his own nose and lungs to test the nature of the gases delivered by the machine and the integrity of the anesthetic circuit.

The anesthesiologist's ear and lungs can also be used to determine rapidly and accurately the precise placement of an endotracheal tube. One can use the ear if the patient is breathing spontaneously or the lungs if he/she is apneic. It is quite surprising how sensitive and how reliable are the chemo and baro-receptors of the human respiratory tract. The human ear is less reliable, but the pinna can feel air movement even if the cochlea is not functioning.

To those who fear the alleged deleterious effects of traces of anesthetic gases and vapours I can only say: firstly, that I have used the manoeuvres outlined above for an ongoing period of 50 years; secondly, that I had to submit to vasectomy to limit the fertility of myself and my wife; and thirdly (but, I believe, most importantly) that OR staff is daily exposed to the vapours of biocidal solutions which are used for cleaning and sterilizing environment and instruments. By definition these agents are lethal to living organisms. I am surprised that they were not first excluded as being possibly noxious to OR staff, before rushing to incriminate agents which our patients receive in high concentrations and for long periods without any very obvious deleterious effects. (I exclude accidents.)

So far, I have not been able to discover ANY study of the effects of biocidal agents on the virility, fertility and general health of anesthesiologists or nurses. Should such evidence exist, I would greatly appreciate a brief note citing the reference. Thank you.

Cecil Stanley Jones, F.F.A.R.A.C.S. Sangrove, Rondebosch

Republic of South Africa


1. Holland R: Foreign Correspondence: Another 'Wrong Gas' Incident in Hong Kong. APSF Newsletter 1991;6:9

Irrigation Solution Lines Pose Hazard

To the Editor

The practice of hanging irrigation solutions (for cystoscopy, arthroscopy, and wound debridement) in close proximity to intravenous fluids poses many potential hazards to patient safety during anesthesia, especially during a crisis. The following drawbacks were observed in four teaching hospitals in the Buffalo area:

(i) Loss of valuable. time in starting inotropes and other cardiac drugs since the IV poles and hooks are preempted by irrigation fluid bottles.

(ii) Accidental withdrawal and use of irrigation solution as solvent for drugs in powder form.

(iii) Opening up the irrigation line stopcock instead of the IV line stopcock to increase the IV infusion rate.

(iv) Accidental injection of drugs into the irrigation tubing instead of the IV line.

(v) Masking of audio alarms by pulsatile jet irrigation device.

Apart from the above mentioned hazards, the irrigation system adds to the clutter and crowding of tubes and wires at the head end of the patient. Keeping the irrigation solutions well away from the immediate extra-personal space of the anesthesiologist will greatly improve the speed and efficiency of the anesthesiologist's response to a -crisis and help -avert potentially dangerous mishaps.

M. Kumar, M.D. Buffalo, NY

"Practice Pressure" A Constant Threat to Patient Safety


Has this scenario ever happened to you? You are running late, your referring surgeon is anxiously awaiting your presence, and your case assignment has suddenly been changed. You encounter a patient with multiple medical problems for whom you are requested to provide anesthesia care. The natural tendency and the pressure to "get the case going" inevitably results in your cutting corners in your pre-anesthetic assessment and construction of an anesthesia plan. Don't let this happen.

Despite the potential consequences of such practice pressures and the impact on your relationship with referring physicians, hospital personnel, etc., do not yield to the temptation to .get the case going' at any cost. You will most likely be doing yourself and more importantly the patient a disservice. The mental processes of the practice of anesthesiology and proper preparation for every anesthetic mandate that appropriate time and attention be devoted to each patient.

Granted that clinical urgency may dictate expediency, we must not lose sight of the fact that hasty evaluation and planning for an anesthetic has the potential to result in disastrous consequences. If and when you find yourself in such a situation, it is helpful to explain to all parties involved your concern for the appropriate evaluation and planning for anesthetic management. Even five or ten extra minutes for thoughtful preparation will result in better patient care, improved outcomes, and less potential need later for crisis management.

Virtually everyone understands the importance of thorough patient assessment and the resultant anesthetic plan with contingencies for unforeseen events. Do not let your ego or the surgeon's insistence compromise this thoughtful process.

I share these thoughts with you because I have found myself in this situation on numerous occasions. I trust that my experience is not unique in the practice of anesthesia. I find that if I simply take a deep breath, refuse to succumb to the practice pressure, and perform an unhurried patient evaluation and formulate the resulting anesthetic plan, everyone benefits. When I have hurried and 'cut corners," I found myself in undesirable clinical scenarios. It is my opinion that inadequate evaluation and preparation for administration of an anesthetic is an occurrence we can all prevent, thereby improving patient care, patient outcome, and our own self satisfaction with a job well done.

Casey D. Blitt, M.D.

Old Publeo Anesthesia, Tuscon, AZ

Member of the APSF Board of Directors

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Editorial response: A Surgeon's View

I am pleased to comment on Dr. Blitt's brief editorial on patient safety in the face of pressure to .get the case going."

I am highly sympathetic to his views for at least two reasons. First, I had a three-month anesthesiology rotation during my surgical residency in Cincinnati. From this brief experience I came to understand to some degree how things look from the other side of what used to be known as the ether screen.

Second, during many years of doing cardiac and other operations with anesthetic management regularly provided by a meticulous, deliberate anesthesiologist, I cannot recall ever telling this splendid person to speed up the process. I do recall many times when I was tempted to do so, but never succumbed because his performance was so outstanding, with an unparalleled safety record, that it seemed unwise to meddle with such superb clinical skills. If he wanted everything to be just right, it seemed obvious that this degree, of concern was in the patient's best interest, as well as my own.

It is only speculation, but I would wager that those surgeons whose impatience led them to try to hurry this anesthesiologist got a polite response followed by the same meticulous preparation that was his trademark.

C. Rollins Hanlon, M.D.

American College of Surgeons Chicago, IL

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Is Competency with our Equipment a Safety Problem?

by Joachim S. Gravenstein, M.D.

An FDA study which used modem anesthesia machines especially modified to produce different dangers and faults was recently reported in the ASA Newsletter (Lees DE: Pre-operative check-list revisited. August, 1991, 55(8):9-11). The results of the study were disappointing; many anesthesiologists clearly did not have a thorough understanding of their anesthesia machine.

These observations do not come as a surprise to experienced clinicians. The relentless progress of technology in anesthesia has confronted us with an ever-growing number of machines and devices, and with it have grown the difficulties of thoroughly understanding the underlying technology and mastering the operation of the devices. As clinicians, we like to remind our friends from industry that our primary interest is the patient and that we do not Re to divert our attention from the patient to equipment which, after all, is there to help us rather than to challenge us.

The problem we encounter may be described with this imaginary but not unlikely scenario:

The anesthesia staff of Hospital X decides to buy a device from Company Y. The device is a sophisticated intravenous drug delivery system that also monitors a number of parameters. The device promises to offer distinct advantages in the care of a category of patients requiring anesthesia. When the device is delivered to the department, an 'in-service' is arranged. This takes place from 2 to 4 P.M. on a workday. Only about half of the anesthesiologists in the department can attend; the others are busy in the operating room. Of those who attend the in--service, the majority will use the equipment right away, but one or two have assignments elsewhere, and thus will not be able to become thoroughly acquainted with the new apparatus. Half a year later, during an emergency at midnight, one of the anesthesiologists who went through an in--service but subsequently did not use the equipment has a patient in great need of the equipment but he cannot recall some of the details of its operation.


Of course, the equipment came with a 3-inch thick manual that describes in great detail how the unit works. This book, however, was written by engineers who were proud of the great flexibility and sophistication of the unit they had designed. The unit, therefore, had multiple knobs triggering cascades of programs suitable to make the unit perform in any one of many different modes. However, before the manual describing the sophistication of the apparatus was sent out, the corporate attorneys of the company went over the manual and added disclaimers and cautionary statements, all couched in a language not designed to make for easy reading. The anesthesiologist did not need to worry about the shortcoming of this printed material because it had long since been lost. Thus the clinician had to decide whether to deny the patient the benefit of a potentially useful device or to attempt to operate it as fully and correctly as he possibly could figure out.

The Committee on Education and Training of the APSF has met repeatedly during the last two years to discuss this difficult issue with representatives from a number of companies. All participants in these discussions agree that we do have a problem and that the problem has many facets, prominent among them:

1. Clinicians tend to be very busy, working long and often unpredictable hours. This makes it difficult for them to be available when educational in-service exercises are planned, particularly if these are extensive. A single in--service may well be inadequate because a lesson learned will soon be forgotten unless the clinician uses the equipment regularly after a successful session.

2. The designers of equipment used by anesthesiologists do not always take clinical realities sufficiently into account. The manufacturers' pride in providing elegant operational features is understandable; but some sophisticated features may add only marginally to the utility of the equipment while contributing significantly to the requirement for extensive educational sessions before the equipment can be used properly. Standardization of equipment has been achieved in many areas, for example, the arrangement of gas pedal, brake, and clutch in automobiles. In anesthesia the manufacturers of equipment have many opportunities to standardize features of their equipment and thus make life easier for the clinician. Organizations of users of the equipment have been slow to formulate guidelines which might be helpful to industry. Beyond voluntary standardization, many improvements relating to the man-machine interface of equipment are conceivable.

3. The instructional material that comes with equipment is frequently woefully inadequate. The descriptions do not cater to the requirements of the clinician and ease of understanding. Furthermore, even though the equipment will be used by many different clinicians, most units come with only one set of instructions which have a tendency to get lost in busy hospitals.

What can be done about these problems?

The question has been raised whether anesthesia personnel should demonstrate mastery of operation of the equipment before they can actually use it in the clinical setting. The analogy has been made that this would be no less than is required of pilots who must demonstrate their competence in the operation of specific aircraft before being permitted to operate the aircraft. Anesthesia practice does not lend itself to such an approach. Yet, we must recognize that we do have problems and we must begin to work toward their solutions.

We believe that these problems need to be addressed by clinicians and by industry. We recommend for discussion the following three steps suggested to minimize the existing problems:

1. We recommend that representatives from anesthesia and industry put their heads together to identify problems and to work toward a solution, perhaps with help from experts in human factors. For example, to assess the magnitude of the problem, the manufacturers of anesthesia machines and ventilators or of certain monitors might prepare a simple questionnaire covering basic features of the equipment. Anesthesia providers might then test themselves (anonymously) to see whether or not they have an adequate grasp of key features of the equipment. If not, their shortcomings should offer the manufacturers excellent information on how to improve the design of the equipment, the operation manual, and the in--service approach.

2. We recommend that practitioners and departments determine if members have an adequate understanding of the equipment in use in the given department. If the result of such a determination shows that deficits exist, the practitioners or the department should develop locally appropriate solutions to improve the situation.

3. We recommend that industry make more use than heretofore of clinical input in the design of their equipment and in the description of their equipment and its operation. We also recommend that the equipment be accompanied by Operator Manuals for every individual user.

The work required to improve what we believe to be a problem will not be completed overnight, but a joint effort of clinicians and industry should greatly benefit our patients.

Dr. Gravenstein, University of Florida, Gainesville, is chairman of the Anesthesia Patient Safety Foundation Committee on Education and Training.

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APSF Committee on Education and Training:

Joseph S. Arcarese

Paul E. Berkebile, M.D.

Michael L. Good, M.D.

Beverly K. Nichols, CRNA

Ellison C. Pierce, M.D

Arthur Schneiber, M.D.

Peter J. Schreiber

N. Ty Smith, M.D.

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"Medic Alert" System for Difficult Airway is Subject of National Communication Effort

by Lynette J. Mark, M.D.,

Improvement of communications with subsequent anesthesia personnel concerning a patient who is discovered to have a difficult airway is the goal of a new program designed to help warn of identified anesthesia risks. Very often today, even if it is explained to the patient in detail and he/she is given a letter to carry, the patient cannot be relied upon to transmit information to subsequent anesthesia providers. If the previous anesthetic record is at another institution, or, sadly, often even in the same institution, it is frequently not available to anesthesiologists making preanesthetic evaluations. Thus, critical information about difficult conditions or past overt adverse events may not reach the personnel most in need of it to safely anesthetize the patient.

The Division of Critical Care Anesthesia at Johns Hopkins Medical Center has been working with Ms. Joyce Drake of the Medic Alert Foundation International to insure that once an airway event happens, consistency in documentation and an easily accessible central data bank are available. From experiences and questions raised by the work of the American Society of Anesthesiologists Difficult Airway Task Force, and Drs. Benumof, Norton, Ovassapian, and others, we specifically addressed the question 'Is there a uniform way that patients and physicians can be informed of critical information?"

Existing practices for the dissemination of information include: anesthesia record (non uniform, handwritten, not easily interpreted); progress notes (not consistently entered, questions about intent and content); and post-operative patient visit (not consistent, questions about purpose, questions about patient understanding or retention).

New directions that we have been working on include: The Anesthesiology Consultant Report (ACR). The ACR is a brief, 1-2 page report that conveys information about perioperative evaluation and preparation, operating room techniques and management, and perioperative recommendations for future anesthetics to our medical, surgical, and anesthetic colleagues. The ACR is intended to supplement the intra-operative anesthesia record, not replace it, although it could conceivably replace the postanesthesia note. This project is supported by an Education Research Grant from the Foundation for Anesthesia Education and Research.

We will have a full report on it within the year. To date, we have identified issues and limitations of the ACR: acceptance by anesthesia colleagues to change existing practice; time to generate an ACR; question of relative worth versus aggravation of excessive paperwork in the medical record system. We have, however, identified a critical group of patients in which a document such as the ACR becomes eminently worthwhile those with difficult airways or intubations. We felt that identification and documentation of events relating to these patients was so critical that we developed an in-hospital identification system as described below.

Difficult Airway/Intubation : Patient Wrist Band and Chart Label. We received institutional review board approval to place a highly visible temporary bracelet on any patient identified as having a difficult airway or intubation and a special label on the hospital chart. (An existing model to compare is the "allergy alert bracelet" that many hospitals already use). Select patients are recommended for and enrolled into the permanent Medic Alert Foundation International emergency medical ID system.

Difficult Airway/Intubation Alert: Medic Alert Foundation International. We officially established a category, 'difficult airway/intubation,' and created a brochure to explain to physicians and patients about difficult airway/intubation and Medic Alert. Medic Alert is a non-profit international organization that provides health care personnel with immediate 24 hour access to a computerized medical record/data bank. The patient is given a wallet card containing his or her medical record and a highly visible permanent bracelet or necklace to attract the attention of health care personnel should the patient fail to or be unable to relate his/her problem. The one-time enrollment fee of 0.00 is traditionally paid by the patient. Indigent patients may be enrolled at no fee if the application is accompanied by a letter from the enrolling physician. The application requires patient consent. Yearly, the patient receives an updated wallet card; physicians can update the medical record any time (the fee for updating is $7.00).

The Medic Alert data bank is in existence and functioning. Use of the brochure simplifies patient management, but patients can be enrolled without the specialized application by completing a standard Medic Alert application and identifying: Difficult Airway/Intubation; Medical Institution and medical record #, procedure and date, clinically applied algorithm, recommendations for colleagues, and significant medical conditions. Additionally, the application should be mailed to the attention of Joyce Drake.

For further information regarding enrollment of patients or to receive the specialized application, contact Dr. Lynette Mark, Johns Hopkins University (410-955-6482/80) or Ms. Joyce Drake, Medic Alert, Chicago Regional Office (312-2806366).

Future directions for study include revision of the Medic Alert application to include 'research questions" to begin to amass a data bank of information that may ultimately help facilitate the prospective identification of difficult airway/intubation patients, help devise new technologies and airway/intubation strategies, etc.

The Hopkins Division of Critical Care Anesthesia conducted a survey during the March International Anesthesia Research Society Annual Meeting using a 'Difficult Airway/Intubation Alert, Dissemination of Information Questionnaire.' Eighty-five people responded and 80 supported the concept of Difficult Airway/Intubation Alert, Medic Alert.

This project has now considerably evolved and the investigators are formulating a prospective study to access the acceptability, implementation, and efficacy of the Difficult Airway/Intubation Alert with at least five major institutions that we anticipate will include Hopkins, Massachusetts General (Dr. Roberts), University of Michigan (Dr. Norton), George Washington (Dr. Epstein), and the Chicago V.A. (Dr. Ovassapian).

Dr. Mark is a member of the Division of Critical Care Anesthesia, Johns Hopkins Medical Center, Baltimore, MD.

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ASA Safety Tapes Add "Difficult Airway II"

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

The Difficult Airway, Part Two: Management The Cricothyroid Membrane, ASA Videotape No. 16, will be available for distribution by the Burroughs Wellcome Company beginning this summer.

The tape, funded through an educational grant from Burroughs Wellcome, examines in detail the techniques of transtracheal jet ventilation, retrograde intubation, and cricothyroidotomy. It was filmed in the studios at the University of California, San Diego, with Terence M. Davidson, M.D., as producer/writer and Ms. Beth Meyer as director. Special thanks went to Harvey Shapiro, M.D. (host/narrator), Gayle Woodson, M.D., Steven Saltz, M.D., and Tony Sanchez, M.D.

The entire airway safety series has been overseen by the ASA Patient Safety and Risk Management Committee's Task Force on The Difficult Airway. Serving on the task force are:

Robert A. Caplan, M.D., chairman; Jonathan L. Benumof, M.D., Michael J. Bishop, M.D., Casey D. Blitt, M.D., Frederick W. Cheney, M.D., David M. Gaba, M.D., Ellison C. Pierce, Jr., M.D., Mark H. Zornow, M.D., and Terence M. Davidson, M.D., Professor of Surgery (Head and Neck), Associate Dean for Continuing Medical Education, University of California, San Diego. The series is a production of the Office of Learning Resources-Television, School of Medicine, University of California, San Diego.

The Airway Safety Videotape, Part Three: Fiberoptic Intubation, will be filmed in early summer and made available to anesthesia practitioners in the Fall.

Part One: The Algorithm, an ASA funded tape, was made available for distribution in August 1991.

All tapes in the ASA Patient Safety Videotape Series, many of which are still available, are distributed by Burroughs Wellcome representatives. Available tapes include:

Cassette A

Videotape No. I ASA Series Overview

Videotape No. 2 Preventing Disconnection in the Breathing Circuit

Videotape No. 3 Anesthesia Machine Checkout Cassette B

Videotape No. 4 Anesthesia Record keeping

Videotape No. 5 Human Error in Anesthesia

Videotape No. 6 Adverse Events Cassette C

Videotape No. 7 Monitoring with the Six Senses

Videotape No. 8 Monitoring with Instruments

Videotape No. 9 Anesthesia Equipment Service: An Organized and Cooperative Approach to Maintenance and Repair

Videotape No. 10 Margin of Safety: Monitoring the Neuromuscular junction

Videotape No. 11 Emergence: Patient Safety in the Post-Anesthesia Care Unit

Videotape No. 12 The impaired Practitioner

Videotape No. 13 Safety Considerations in Obstetrical Anesthesia

Videotape No. 14 Anatomy of an Anesthesia Machine

Videotape No. 15 The Difficult Airway, Part One: The Algorithm

Videotape No. 16 The Difficult Airway, Part Two: Management -The Cricothyroid Membrane

Dr. Pierce is President of the APSF and Executive Producer of the ASA Patient Safety Videotape Series.

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Foreign Correspondence: Day Surgery Recovery: When Is It Safe to Discharge to Home
We Could Not Even Recognize Perfection

by Michael Rosen

A great deal of concern has been shown about patients' return to full activity after "day-stay' (outpatient) surgery. When is it safe to do so? When would it be legally acceptable to drive? When would it be acceptable to drive a public service vehicle? Or fly an aeroplane? Mostly, a cautious approach is justified, especially in the case of sensitive occupations which could cause damage to more than the individual. What seems to be reasonable then is to take a minimum period based on the pharmacokinetics of the drugs, and then add a further period for safety. That is the cautious approach.

There are two related issues which are often overlooked and require closer examination. Firstly, we accept that those who have minor procedures under local anaesthetic need not restrict their activities. When the patient has a larger dose of local anaesthetic and certain areas are blocked (e.g. a limb) there would be some restrictions imposed, although attitudes may vary greatly. We assume that after local anaesthetic in smallish doses, the patient is not impaired. However, the stress of the situation may have effects. This too should be checked! It is not good enough to assume all is well because the accident rate appears low.

Secondly we ought also to encourage much wider reporting of the incidence of drugs other than alcohol in road casualties. The data is poor as it is; and there is no compulsion to ask or to tell. Perhaps a compulsory urine sample would be appropriate.

When it comes to general anaesthetics, the assumption is that no one ever recovers promptly. The tests that we use are still relatively crude and it can be most difficult to detect impairment. If we can detect a decrement in performance we may assume impairment. However, the converse is not acceptable: no decrement cannot be taken to indicate full recovery. And herein lies the quandary. We know that drugs are being improved all the time. For example, the introduction of propofol is a step forward. Moreover it is not too great a jump in imagination to anticipate a drug which breaks down completely into totally inactive fragments almost instantly (e.g. within 15 minutes). With the emergence of a near-perfect drug, could we actually test for lack of impairment? I doubt whether it is possible now. Perfection could pass us. by unrecognized.

These are matters which are growing in importance with the increase in day-stay surgery and the requirement to get individuals back to work swiftly.

Dr. Rosen is a member of the Department of Anaesthetics, University of Wales College of Medicine, Cardiff. Reproduced with permission of the publisher from The Recovery Times, the second letter @f the Recovery Interest Group, August, 1991.

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Event Case Reports Sought

The Anesthesia Patient Safety Foundation is seeking reports of interesting safety-related events. If you have been involved in, or, witnessed, an event that might teach other anesthesiologists how to better avoid or manage a difficult situation, please let us know. We welcome any reports but we are particularly interested in events involving human factors issues and potentially preventable close-cause.

All reports should be ANONYMOUS. Do not include any identifiers or an inside return address. We intend to publish as many interesting reports as possible in the APSF Newsletter, along with comments when appropriate.

Remember, YOU are your colleagues' best teacher!

Send your reports to:

David M. Gaba, M.D.

Secretary, Anesthesia Patient Safety Foundation

Anesthesiology Service, 112A

Palo Alto VAMC

3801 Miranda Avenue

Palo Alto, CA 94304

Look forward to the 'Experience is the Best Teacher" column in upcoming APSF Newsletters.

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Safety booth at the ASA: Shown above is the ASA committee on Patient Safety and Risk Management display booth at last year's annual meeting of the American Society of Anesthesiologists. David Sprague, M.D. (left) of the University of North Carolina was the exhibit coordinator. David Gaba, M.D. (right), of Stanford University, APSF Secretary, holds a transtracheal jet ventilator. The APSF section of the exhibit featured information about the difficult airway but abundant other literature was available for distribution. Plan to visit the booth at this year's ASA.

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, 1992

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

APSF Executive Committee:

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

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., Nancy Gondringer, C.R.N.A.; Jeffrey S. Vender, M. D., Ralph A. Epstein, M.D., Bernard V. Wetchler, M.D., Mr. Mark D. Wood.

Editorial Assistant Ms. Nola Gibson

Address all general, membership, and subscription correspondence to:


Anesthesia Patient Safety Foundation

515 Busse Highway

Park Ridge, IL 60068

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 39216-4505

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