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Biomedical subjects

D M Gaba

Publications and source records attributed to D M Gaba.

At least 19 recordsLinked to original sources
PubMed1998

Assessment of clinical performance during simulated crises using both technical and behavioral ratings.

BACKGROUND: Techniques are needed to assess anesthesiologists' performance when responding to critical events. Patient simulators allow presentation of similar crisis situations to different clinicians. This study evaluated ratings of performance, and the interrater variability of the ratings, made by multiple independent observers viewing videotapes of simulated crises. METHODS: Raters scored the videotapes of 14 different teams that were managing two scenarios: malignant hyperthermia (MH) and cardiac arrest. Technical performance and crisis management behaviors were rated. Technical ratings could range from 0.0 to 1.0 based on scenario-specific checklists of appropriate actions. Ratings of 12 crisis management behaviors were made using a five-point ordinal scale. Several statistical assessments of interrater variability were applied. RESULTS: Technical ratings were high for most teams in both scenarios (0.78 +/- 0.08 for MH, 0.83 +/- 0.06 for cardiac arrest). Ratings of crisis management behavior varied, with some teams rated as minimally acceptable or poor (28% for MH, 14% for cardiac arrest). The agreement between raters was fair to excellent, depending on the item rated and the statistical test used. CONCLUSIONS: Both technical and behavioral performance can be assessed from videotapes of simulations. The behavioral rating system can be improved; one particular difficulty was aggregating a single rating for a behavior that fluctuated over time. These performance assessment tools might be useful for educational research or for tracking a resident's progress. The rating system needs more refinement before it can be used to assess clinical competence for residency graduation or board certification.

Anesthesiology↗
PubMed1997

Evaluation of a medical diagnosis system using simulator test scenarios.

This paper describes an informal but systematic method for how to test and verify a knowledge-based system in a large open-ended medical target domain. The system used is Guardian, an intelligent system for monitoring and diagnosis of post-cardiac surgery patients in an intensive-care unit. The knowledge base is tested and verified by running the system on a series of realistic test scenarios, both with an embedded simulator and with an external simulation system. The same scenarios are presented to human test subjects, making it possible to compare and analyze the performance of the knowledge-based system with that of human physicians. The use of simulators instead of clinical data also means that it is possible to test crucial scenarios which occur seldom in medical practice. Our results show that a system like Guardian might indeed be useful in medical care.

Artificial Intelligence↗
PubMed1997

The effect of electronic record keeping and transesophageal echocardiography on task distribution, workload, and vigilance during cardiac anesthesia.

BACKGROUND: Electronic anesthesia record keeping (EARK) systems increasingly are used in the operating room, but studies have only recently begun to investigate their effect on anesthesia task performance. Teak analysis, workload assessment, and vigilance assessment techniques were used to study senior residents providing anesthesia for coronary artery bypass graft (CABG) procedures. The impact on anesthesia residents' workload of the routine use of transesophageal echocardiography (TEE) also was examined. METHODS: Before each case, the record keeping system was randomly selected as either electronic (Distek ARKIVE; EARK) or traditional manual recording (MAN). Twenty CABG procedures (10 EARK and 10 MAN) were examined, with observation commencing with anesthetic induction and terminating on initiation of cardiopulmonary bypass. The activities of each resident, divided into 32 task categories (e.g., "laryngoscopy," "observe monitors," etc.), were recorded by a trained observer using a computer. The response latency to a randomly activated alarm light was used as a measure of vigilance ("vigilance latency"). Workload was rated by subject and observer at random 10- to 15-min intervals throughout the case. Data analysis included calculation of workload density (number of tasks/min multiplied by task-specific workload values) and task-links (relationship between sequential tasks). RESULTS: The two groups had a similar distribution of tasks before intubation. In only 4 of the 20 cases studied did any manual record keeping occur before intubation. After intubation, the EARK group spent less time record keeping and using the TEE but more time observing the monitors and conversing with the attending physician than the MAN group did. All subjects reported significantly higher workload scores before intubation compared with after intubation. Similarly, vigilance latency was greater before intubation compared with after intubation (57 vs. 31 s; P < 0.001). There were no significant differences between the two record keeping groups in subjective workload scores, workload density, or vigilance latency. During TEE use, vigilance latency was significantly longer, and workload density was greater than during other monitoring or recording tasks. CONCLUSIONS: This study provides an objective description of the task distribution and workload during the administration of anesthesia for cardiac surgery. Under the conditions of this study. EARK use modestly decreased the time spent record keeping during the postintubation prebypass period. However, there was no effect of EARK either on vigilance or several measures of workload. TEE use was associated with increased workload and possibly decreased vigilance.

Anesthesiology↗
PubMed1997

Anesthesia patient risk: a quantitative approach to organizational factors and risk management options.

The risk of death or brain damage to anesthesia patients is relatively low, particularly for healthy patients in modern hospitals. When an accident does occur, its cause is usually an error made by the anesthesiologist, either in triggering the accident sequence, or failing to take timely corrective measures. This paper presents a pilot study which explores the feasibility of extending probabilistic risk analysis (PRA) of anesthesia accidents to assess the effects of human and management components on the patient risk. We develop first a classic PRA model for the patient risk per operation. We then link the probabilities of the different accident types to their root causes using a probabilistic analysis of the performance shaping factors. These factors are described here as the "state of the anesthesiologist" characterized both in terms of alertness and competence. We then analyze the effects of different management factors that affect the state of the anesthesiologist and we compute the risk reduction benefits of several risk management policies. Our data sources include the published version of the Australian Incident Monitoring Study as well as expert opinions. We conclude that patient risk could be reduced substantially by closer supervision of residents, the use of anesthesia simulators both in training and for periodic recertification, and regular medical examinations for all anesthesiologists.

Accidents↗
PubMed1995

Anesthesia crisis resource management: real-life simulation training in operating room crises.

Little formal training is provided in anesthesiology residency programs to help acquire, develop, and practice skills in resource management and decision making during crises in practice. Using anesthesia crisis resource management (ACRM) principles developed at another institution, 68 anesthesiologists and 4 nurse-anesthetists participated in an ACRM training course held over a 2 and a half-month period. The anesthesia environment was recreated in a real operating room, with standard equipment and simulations requiring actual performance of clinical interventions. Scenarios included overdose of inhalation anesthetic, oxygen source failure, cardiac arrest, malignant hyperthermia, tension pneumothorax, and complete power failure. A detailed questionnaire was administered following the debriefing and completed by all participants, documenting their immediate impressions. Participants rated themselves as having performed well in the simulator. Senior attendings and residents rated themselves more highly than did their junior counterparts. The potential benefit of this course for anesthesiologists to practice anesthesia more safely in a controlled exercise environment, was rated highly by both groups. Over one half of respondents in all categories felt that the course should be taken once every 12 months; another third of each group felt that the course should be taken once every 24 months. While no senior attendings believed that the course should be taken once every 6 months, approximately 10% of respondents in other categories that it should. Of respondents in the senior and junior attending category, 5% felt the course should never be taken. Although attendings were less favorable than residents in their rating of the value of the course, both groups were still enthusiastic.

Anesthesia↗
PubMed1995

Situation awareness in anesthesiology.

Situation awareness has primarily been confined to the aviation field. We believe that situation awareness is an equally important characteristic in the complex, dynamic, and risky field of anesthesiology. We describe three aspects of situations of which the decision maker must remain aware: subtle cues, evolving situations, and special knowledge elements. We provide examples of real or simulated anesthesia situations in which situation awareness is clearly involved in the provision of optimal patient care, and we map the elements of situation awareness onto a cognitive process model of the anesthesiologist. Finally, we consider how situation awareness can be further investigated and taught in this medical domain using anesthesia simulators and analyses of real cases. The study of situation awareness in anesthesiology may provide a good example of the wider application of the concept of situation awareness to nonaerospace environments.

Adult↗
PubMed1994

An objective methodology for task analysis and workload assessment in anesthesia providers.

BACKGROUND: Administering anesthesia is a complex task in which either human or equipment failure can have disastrous consequences. An improved understanding of the nature of the anesthesiologist's job could provide a more rational basis for improvements in provider training as well as the design of anesthesia equipment. The objective of this study was to develop a set of techniques to evaluate anesthesiologist performance and to determine what information could be obtained from performing real-time task assessment and workload analysis tests in the operating room. METHODS: The methodology used included time-motion analysis, secondary task probing, and subjective workload assessment. The time-motion data was subjected to subsequent analysis to generate quantitative measures such as task duration (time spent focused on an individual task) and task density (the number of tasks initiated per minute). The latency of response to a "vigilance light" was used as a secondary task probe. Finally, both the observer and the subjects themselves scored workload at 10-15-min intervals throughout the case. Two groups of anesthesia providers performing general endotracheal anesthesia for simple ambulatory surgical cases (1-4 h duration) were examined using this methodology. In the first group, 3rd-yr anesthesia residents and experienced certified registered nurse anesthetists (n = 11) performed cases under limited supervision by an attending anesthesiologist. In the second group, novice residents in their first 8 weeks of training (n = 11) performed similar cases under nearly constant attending supervision. RESULTS: The two groups seemed to manifest different patterns of task behavior, task density, subjective workload, and latency of response to the vigilance task. Response latency to the vigilance task increased at times of increased workload (e.g., during induction of anesthesia). The experienced (less supervised) providers spent significant amounts of time observing the monitors and the surgical field, whereas the novice subjects spent more time conversing with the supervising attending. Despite performing fewer tasks per minute (lower task densities), the novice subjects exhibited longer latencies of response to the vigilance light and increased subjective workload. Novice subjects also had longer task duration values. For example, postintubation, novices focused on their monitors for an average of twice as long as did experienced subjects (13 +/- 2 vs. 7 +/- 1 s) before moving on to another task. CONCLUSIONS: These techniques permitted an objective description of task characteristics, workload, and vigilance in anesthesia personnel under actual work conditions. This methodology could aid in understanding the factors that affect anesthesiologists' performance and may prove useful in assessing the progress of training.

Anesthesiology↗
PubMed1994

Production pressure in the work environment. California anesthesiologists' attitudes and experiences.

BACKGROUND: Pressure to put efficiency, output, or continued production ahead of safety has caused catastrophic accidents in various industries. The authors assessed the attitudes and experiences of anesthesiologists concerning production pressure. METHODS: A random, repeated-mailing survey was conducted among 647 members of the American Society of Anesthesiologists residing in California. Questions were asked about attitudes toward production pressure and other patient safety issues, frequency of occurrence of various operating room events, encounters with situations involving unsafe actions, and ratings of sources of production pressure. RESULTS: Forty-seven percent of those sampled returned surveys. The demographics of the respondent population were largely similar to those of the population of anesthesiologists in California. There was no systematic difference between the respondents to the first versus the second mailing, reducing (but not eliminating) the possibility of self-selection bias. Nearly half (49%) of respondents had witnessed production pressure result in what they believed to be unsafe actions by an anesthesiologist. Such events included elective surgery in patients without adequate evaluation or with significant contraindications to surgery. Anesthesiologists felt pressures within themselves to work agreeably with surgeons, avoid delaying cases, and avoid litigation. They also reported overt pressure by surgeons to proceed with cases instead of cancelling them, and to hasten anesthetic procedures. Some aspects of production pressure were perceived differently by those reimbursed by fee-for-service versus those paid by salary. CONCLUSIONS: Production pressure from internal and external sources is a reality for many anesthesiologists and is perceived in some cases to have resulted in unsafe actions being performed.

Anesthesiology↗
PubMed1992

Bronchial cuff pressures of two tubes used in thoracic surgery.

The pressure/volume characteristics of the bronchial cuff of a polyvinylchloride (PVC) double-lumen endobronchial tube (DLT) was compared with the inflatable cuff of a bronchial blocker. At the volumes needed to seal a series of rigid model bronchi the PVC DLT bronchial cuff consistently generated significantly lower pressures than the bronchial blocker cuff.

Humans↗
PubMed1992

Anesthesia crisis resource management training: teaching anesthesiologists to handle critical incidents.

The authors have developed a course in Anesthesia Crisis Resource Management (ACRM) analogous to courses in Crew (Cock-pit) Resource Management (CRM) conducted in commercial and military aviation. Anesthesiologists do not typically receive formal training in crisis management although they are called upon to manage life-threatening crises at a moment's notice. Two model demonstration courses in ACRM were conducted using a realistic anesthesia simulation system to test the feasibility and acceptance of this kind of training. Anesthesiologists received didactic instruction in dynamic decision-making, human performance issues in anesthesia, and in the principles of anesthesia crisis resource management. After familiarization with the host institution's operating rooms and with the simulation environment, they underwent a 2-h simulation session followed by a debriefing session which used a videotape of their simulator performance. Participants rated the course as intense, helpful to their practice of anesthesiology, and highly enjoyable. Several aspects of the course were highly rated, including: videotapes of actual anesthetic mishaps, simulation sessions, and debriefing sessions. Scores on written tests of knowledge about anesthesia crisis management showed a significant improvement following the first course (residents) but not the second course (experienced anesthesiologists). Although the ultimate utility of this training for anesthesiologists cannot easily be determined, the course appeared to be a useful method for addressing important issues of anesthesiologist performance which have previously been dealt with haphazardly. The authors believe that ACRM training should become a regular part of the initial and continuing education of anesthesiologists.

Anesthesiology↗
PubMed1991

A comparison of etomidate and thiopental anesthesia for cardioversion.

Sixteen ASA class II or III male patients (aged, 52 to 66 years) undergoing elective cardioversion were randomly assigned to receive either thiopental or etomidate according to an observer-blinded, parallel study design. The appropriate drug was administered in 2-mL aliquots every 15 seconds until the patient no longer responded to verbal commands, at which time cardioversion was attempted. The total dose for induction was 0.22 +/- 0.2 mg/kg and 3.2 +/- 0.4 mg/kg for etomidate and thiopental, respectively. The cardiorespiratory data after induction were evaluated for maximal percent change from baseline. The baseline heart rate was 106 +/- 6 beats/min and 98 +/- 8 beats/min for the etomidate and thiopental groups, respectively (mean +/- SEM). The heart rate decreased 5% after induction with etomidate and increased 7% with thiopental (P less than 0.05). The baseline mean arterial pressure (MAP) was 96 +/- 3 mm Hg and 105 +/- 11 mm Hg for the etomidate and thiopental groups, respectively (mean +/- SEM). The MAP decreased 4% with etomidate and 3% with thiopental. Respiratory rate was significantly increased by 22% after etomidate compared with a 22% decrease in respiratory rate with thiopental (P less than 0.05). Seven of eight patients in the thiopental group required only one countershock, whereas four of eight patients in the etomidate group required only one shock. One patient in each group could not be successfully cardioverted. Recovery time and clinical side effects were similar between groups except for mild myoclonus in the etomidate group. Titration to effect of either etomidate or thiopental provided satisfactory anesthesia for elective cardioversion in hemodynamically stable patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Role of experience in the response to simulated critical incidents.

Eight experienced anesthesiologists (faculty or private practitioners) were presented with the same simulated critical incidents that had previously been presented to 19 anesthesia trainees. The detection and correction times for these incidents were measured, as was compliance with Advanced Cardiac Life Support (ACLS) guidelines during cardiac arrest, and the occurrence of unplanned incidents. Experienced personnel tended to react more rapidly than did trainees, but differences between second-year anesthesia residents (CA2) and experienced anesthesiologists were not statistically significant. There was a high variability in performance between incidents and within each group. Unplanned errors and management flaws still occurred with experience subjects. The response to incidents during anesthesia is a complex process that involves multiple levels of cognitive activity and is vulnerable to error regardless of experience. Most trainees seemed to acquire adequate response routines by the end of the CA2 year. Formal reasoning appeared to play a minor role in responding to intraoperative events, but the exact nature of the anesthesiologist's cognition remains to be thoroughly investigated.

Anesthesiology↗