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ECONOMICS, EDUCATION, AND HEALTH SYSTEMS RESEARCH

Management of Simulated Oxygen Supply Failure: Is There a Gap in the Curriculum?

St. Michael's Anesthesia Research into Teaching (SMART) Simulation Group, St., Michael's Hospital, Department of Anesthesia, University of Toronto; Wilson Centre for Research in Education, University of Toronto, Toronto, Ontario, Canada

Address correspondence and reprint requests to Viren N. Naik, MD, MEd, FRCPC, Department of Anesthesia, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, ON, Canada M5B 1W8. Address e-mail to naikv{at}smh.toronto.on.ca.

	Abstract

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In this study we evaluated, in our residency program, the understanding and management of a simulated oxygen pipeline failure. Performances of 20 residents were evaluated by 2 raters. Fourth-year residents did not perform better than second-year residents (P = NS). The majority of the participants either did not have the knowledge to change the oxygen cylinder or did not attempt to change the oxygen, even after prompting. We conclude that the delegation of gas machine maintenance to perioperative personnel, such as respiratory therapists and technicians, may have created a new gap in knowledge and resulted in inadequate training.

	Introduction

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Although rare, anesthesiologists may be confronted with an oxygen supply failure. Closed-claims analyses have described catastrophic outcomes when this event occurs (1). An approach to managing such an event is essential to avoid potentially devastating complications. This requires an understanding of the anesthesia gas machine and its reserve oxygen supply.

The routine checking and maintenance of anesthesia equipment is a task that is increasingly being delegated to nonphysician personnel (2–4). Subsequently, anesthesia trainees may not have adequate exposure to this standard everyday practice. This could result in a diminished ability to manage an equipment-related crisis in the operating room, which may, in turn, compromise patient safety.

High-fidelity patient simulation reproduces the clinical setting to teach and assess clinical skills (5,6). It is an environment in which gaps in a trainee's knowledge, skills, or attitude can be safely identified without placing patients at risk. This can provide useful feedback to trainees and educators and may facilitate the improvement of the curriculum.

The purpose of this study was to evaluate the understanding and management of a simulated oxygen pipeline failure by residents in an anesthesiology training program.

	Methods

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After IRB approval and informed consent, 12 fourth-year and 8 second-year anesthesia residents were recruited as subjects. Confidentiality agreements were signed to ensure that information pertaining to the simulation scenario would not be disseminated. There were no exclusion criteria.

The study was conducted at the Patient Simulation Centre (St. Michael's Hospital, Toronto, Ontario, Canada) using a Laerdal SimMan® patient simulator and monitors (Laerdal Medical Canada Ltd., Toronto, Ontario, Canada), and an Ohmeda 8000® anesthesia gas machine (Datex-Ohmeda Inc., Mississauga, Ontario, Canada), which was incapable of being switched to a closed mechanical ventilation circuit.

All subjects had previous simulation experience. The 10-min scenario was a simulated carotid endarterectomy under general anesthesia. With simulated surgery underway and the carotid artery cross-clamped, there was a loss of pipeline oxygen supply. The reserve oxygen cylinder on the anesthesia gas machine was empty. If requested, subjects were provided with an oxygen cylinder without a regulator. A regulator was delivered if requested. If a new oxygen cylinder was not requested by the subject, one was delivered 4 min after the loss of pipeline oxygen supply. The candidate was then prompted to change the reserve oxygen cylinder. At all times a self-inflating resuscitation (Ambu®) bag, which was placed in obvious sight of the subject, was available to ventilate the patient's lungs. The oxygen supply failure was alleged to be a hospital-wide event, as conveyed to the participant by the perioperative staff; therefore, no technical support was available to the subjects. Two actors played standardized roles of surgeon and circulating nurse. The actors were advised to comply with subject requests and perform delegated tasks. The actors offered minimal help and only prompted the subject when required for progression of the scenario.

All performances were videotaped. Two staff anesthesiologists independently reviewed the tapes assessing each participant's ability to recognize and manage the event appropriately using a 7-item performance checklist. The checklist was constructed using a modified Delphi technique with expert staff anesthesiologists (Appendix 1), (7).

The Cohen's Kappa coefficient was used to assess the interrater reliability for each key action scored with the checklist. After computing the interrater reliability, the two raters reviewed the tapes for areas of disagreement and reached a final score through consensus. The performances of second-year and fourth-year residents were then compared using the Fisher's exact test. A two-tailed P < 0.05 was considered significant.

	Results

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The level of agreement between the raters was very good (overall Cohen's Kappa = + 0.76). It was excellent (Kappa: +0.67 to + 1.0) for 5 items, and fair for 2 items: "recognizes the loss of oxygen supply and pressure alarms" and "calls for a new cylinder" (both Kappa + 0.48).

Table 1 summarizes our results. Although the majority of subjects recognized that the patient was not receiving adequate oxygen, most did not recognize the origin of the alarms indicating an oxygen supply failure. None of the subjects responded by increasing the flow of air in the gas machine. Most subjects did not know how to change the oxygen cylinder or how to open the reserve supply. Furthermore, the majority did not attempt to open or change the cylinder even after being prompted by the surgeon. Almost all subjects exercised the basic procedure of ventilating the patient's lungs with the self-inflating resuscitation bag. There were no significant differences in recognition or management of the scenario between second-year and fourth-year residents.

	Discussion

Top Abstract Introduction Methods Results Discussion Appendix References

 
The results of this study suggest that oxygen supply failure is poorly understood and suboptimally managed by anesthesiology residents. The choice to ventilate with the Ambu® bag instead of attempting to open the reserve tank or change the oxygen cylinder after prompting indicates a lack of the equipment knowledge required to manage this situation safely and efficiently. Also, performances by fourth-year residents were not better than their second-year resident counterparts. This finding contrasts with other technical and nontechnical skills that have been found to improve when comparing junior to senior residents (8–10). Presumably, the reason these skills improve is that they are specifically taught, developed, and practiced in the course of training.

Currently, the task of checking anesthetic equipment is delegated to nonanesthesia personnel. This is in accordance with developed guidelines (2,3,11) and has shifted the focus of maintaining functioning equipment from the anesthesiologist. However, the proper functioning of anesthetic equipment, including the provision of a continuous supply of oxygen, remains the responsibility of the anesthesiologist (11).

The knowledge of equipment forms part of the curriculum of anesthesia residency programs (12). However, the application of this knowledge is often not formally evaluated or likely to be observed during the training period as a result of this task shifting. High-fidelity patient simulation is a useful tool to identify gaps in anesthesia trainee knowledge (13,14). In addition, a resident's performance can be assessed repeatedly. This allows monitoring of progress, early identification of areas of weakness, and the provision of focused individual feedback (15).

Our study has one important limitation. The presence of a second group, routinely exposed to anesthesia machine checking, would have helped to draw stronger conclusions.

In conclusion, this study shows that anesthesia residents are not familiar with the management of oxygen supply failure. High-fidelity simulation has identified this gap in trainees' education and knowledge. We suggest that patient simulation may be a useful tool to identify areas of weakness in a training curriculum in which gaps in knowledge may lead to catastrophic outcomes.

The authors would like to thank the anesthesiology residents at the University of Toronto for their participation in this study. We would also like to acknowledge the contribution of Ms. Erinn Macaulay (Research Student).

	Appendix

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Appendix: Performance Checklist of Oxygen Pipeline Failure Management
Each key action was checked as "Performed" or "Not Performed."

1. Recognizes and understands the meaning of the oxygen failure alarms and loss of pressure in oxygen gauges (wall outlet and anesthesia gas machine)

2. Opens oxygen cylinder on anesthesia gas machine

3. Recognizes that the oxygen cylinder is empty

4. Calls for a new oxygen cylinder

5. Changes the empty oxygen cylinder

6. Ventilates the patient's lungs with the Ambu® bag

7. Anticipates patient awakening

	Footnotes

 
Accepted for publication October 4, 2005.

	References

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1. Caplan RA, Vistica MF, Posner KL, Cheney FW. Adverse anesthetic outcomes arising from gas delivery equipment: a closed claims analysis. Anesthesiology 1997;87:741–8.[Web of Science][Medline]
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3. Australian and New Zealand College of Anaesthetists. Recommendations on Checking Anaesthesia Delivery Systems. http://www.anzca.edu.au/publications/profdocs/profstandards/ps31_2003.htm. 2003.
4. United States Food and Drug Administration. Anesthesia Apparatus Checkout Recommendations. Rockville, MD: Food and Drug Administration, 1993.
5. Issenberg SB, McGaghie WC, Hart IR, et al. Simulation technology for health care professional skills training and assessment. JAMA 1999;282:861–6.[Abstract/Free Full Text]
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7. Duffield C. The Delphi technique. Aust J Adv Nurs 1988;6:41–5.[Medline]
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10. Forrest FC, Taylor MA, Postlethwaite K, Aspinall R. Use of a high-fidelity simulator to develop testing of the technical performance of novice anaesthetists. Br J Anaesth 2002;88:338–44.[Abstract/Free Full Text]
11. American Society of Anesthesiologists. Standards, Guidelines and Statements: The Organization of an Anesthesia Department. http://www.asahq.org/publicationsAndServices/standards/16.pdf. 2001.
12. Education Committee of the Royal College of Physcians and Surgeons of Canada. Objectives of Training and Specialty Training Requirements in Anesthesia. http://rcpsc.medical.org/residency/certification/training/anesth_e.html. 2000.
13. Schwid HA, Rooke GA, Carline J, et al. Evaluation of anesthesia residents using mannequin-based simulation: a multiinstitutional study. Anesthesiology 2002;97:1434–44.[Web of Science][Medline]
14. Morgan PJ, Cleave-Hogg D, DeSousa S, Tarshis J. Identification of gaps in the achievement of undergraduate anesthesia educational objectives using high-fidelity patient simulation. Anesth Analg 2003;97:1690–4.[Abstract/Free Full Text]
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