Editor’s note: Suggestions are welcome for other pertinent articles from the anesthesia patient safety literature to be summarized in future issues.
Caplan R.A., Ward RJ, Posher K., Cheney F.W.: Unexpected cardiac arrest during spinal anesthesia: a dosed claims analysis of predisposing factors. Anesthesiology 68: 5-1 1, 1988.
The authors of this interesting paper reviewed some 900 cases compiled by the American Society of Anesthesiologists Committee on Professional Liability during its nationwide study of closed insurance claims from major anesthetic mishaps. The authors describe 14 cases of intraoperative cardiac arrests during spinal anesthesia in otherwise healthy patients. They maintain that each mishap occurred for less than obvious reasons, and may represent a “sentinel event: an unusual or unexpected outcome that should not occur under the prevailing conditions of health care.” These cases thus provided an opportunity for a detailed analysis that might “reveal recurring patterns of clinical management that contributed either to occurrence or outcome”.
Citing the “almost irresistible tendency to assume that overt negligence has played an important contributory role [in an anesthetic catastrophe]”, the authors were struck by “the overall adequacy of basic anesthetic care” in these cases. The patients were selected for spinal by experienced clinicians, the amount of supplemental sedation did not appear to be excessive, and intraoperative vigilance appeared to be adequate. The highest spinal level was T4′ The average time between the last verification of adequate circulation and ventilation and the first indication of problems was only 1.6 minutes. The average time between the first indication of inadequate circulation or ventilation and the onset of cardiopulmonary resuscitation was also only 1.6 minutes. In spite of prompt resuscitation efforts, six patients died in the hospital and another seven suffered severe neurologic dysfunction.
The authors were able to identify two management patterns which correlated with these poor outcomes. The first was the use of “sufficient sedation to produce a comfortable appearing, sleep like state in which there was no spontaneous verbalization”. This occurred in seven of the patients, and in six of these cyanosis was noted prior to the cardiac arrest. Thus, the possibility of respiratory insufficiency as the precipitant of cardiac arrest was raised for in approximately half of the patients.
A second pattern involved the conduct of CPR. The average duration of CPR was eight to ten minutes; ephedrine and atropine were given early during the resuscitations, but epinephrine was not given until about five minutes after the initiation of CPR, and, on the average, about seven and one half minutes after the first clue of hemodynamic compromise. The authors suggest that the presence of high spinal anesthesia with concomitant sympathectomy, and hence relative intravascular hypovolemia and bradycardia, may have explained the difficulty of successfully resuscitating these patients after the onset of cardiac arrest.
In concluding, the authors reiterate that these cases represent cardiac arrests which “seemed to evolve with unexpected speed against the background of apparently stable hemodynamics.” They point out that they cannot fully understand this based on the data, nor can they determine the incidence of such occurrences, but “wish to emphasize that spinal anesthesia-conducted under routine conditions and in a standard manner-carries a poorly understood potential for sudden cardiac arrest and severe brain injury in healthy patients”.
They offer three suggestions for anesthetic care based on their findings: First, the use of a pulse oximeter for sedated patients; second, the use of epinephrine “early in the treatment of sudden bradycardia”; and third, “a full resuscitation dose of epinephrine. . immediately upon the recognition of cardiac arrest”.
Dr. Arthur Keats, in an accompanying editorial, praises the efforts of the University of Washington team and enlarges the discussion of possible mechanisms for cardiac arrest and inadequate resuscitation of these patients. Caplan and his coworkers have clearly provided a valuable lesson in analysis of this uncommon type of anesthetic mishap.
Abstracted by Kimball C. Atwood, M.D., Harvard Medical School and New England Deaconess Hospital, Boston.
Simulators Studied for Role in Patient Safety
by J.S. Gravenstein, M.D.
The APSF is currently examining what clinical I anesthesia simulators could contribute to the training and education of anesthesiologists and nurse anesthetists.
A number of investigators have developed simulators that can be used to demonstrate the pharmacokinetics of drugs, the responses of patients to anesthesia, the workings of an anesthesia machine, and the meanings of variables reported by monitors, to name a few.
These simulators allow the trainee to “play a scenario” without threatening the safety of the patient and to explore what would happen if an adverse process were allowed to go unchecked. Of course, simulators are widely and successfully used in many other are-as. Best known are the flight simulators employed by all major airlines and the Air Force. These simulators are wonders of technology. Even though they are enormously expensive, (one flight simulator may cost $ 1 0,000,000), the aviation industry has found them to be cost effective. Other users of simulators (including the Navy and the atomic energy industry) concur.
The Foundation raised the question: What can simulators do for us in anesthesia? Will they be simply research toys for a few computer wizards or can they really play an important part in the training and education of clinical personnel?
In September of 1988, the Foundation will bring together a group of educators in anesthesia and the designers of several simulators to answer that question. The educators will have an opportunity to examine and test the simulators (or be tested by them) and explore how these devices might fit into the educational curriculum of trainees as well as programs for continuing education. Once we understand the role simulators might play in our specialty, we can ask the question whether these newcomers to medicine will be cost-effective.
Dr. Gavenstein, University of Florida, Gainesville, is a member of the APSF Executive Committee.