Crisis management during anaesthesia: bradycardia

Background: Bradycardia in association with anaesthesia may have many potential causes and associated conditions, some rare and/or obscure. A prompt appropriate response is important as some homeostatic mechanisms may be impaired under anaesthesia. Objectives: To examine the role of a previously described core algorithm “COVER ABCD–A SWIFT CHECK”, supplemented by a specific sub-algorithm for bradycardia, in the management of bradycardia occurring in association with anaesthesia. Methods: The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. Results: From the first 4000 incidents reported to AIMS, 265 reports which described bradycardia during anaesthesia were extracted and studied. Bradycardia was associated with hypotension in 51% of cases, cardiac arrest in 25% of cases and hypertension in one case. In 22% of reports apparent desaturation or an abnormality of ventilation was described. Bradycardia was caused by drug events (28%), airway related events (16%), autonomic reflexes (14%), and regional anaesthesia (9%). Airway and drug events caused 75% of cases involving children. It was considered that, correctly applied, the core algorithm COVER would have diagnosed 53 cases (20%) and led to corrective management in 45 (85%) of these; this included an important subset of airway and ventilation problems. Completion of COVER ABCD–A SWIFT CHECK followed by the specific sub-algorithm for bradycardia would have resulted in diagnosis and appropriate management in all but two cases. It would have led to earlier recognition of the problem and/or better management in 11 cases (4%) when compared with the actual management described in the reports. Conclusion: Steps should be taken to manage bradycardia whilst associated conditions are managed concurrently. Analysis of cardiac rhythm should not be pursued to the exclusion of supportive therapy. The use of a structured approach in the management of bradycardia associated with anaesthesia is likely to improve management in the small percentage of cases in which the diagnosis of the cause may be missed or delayed.