The regional anesthesia "learning curve". What is the minimum number of epidural and spinal blocks to reach consistency?

BACKGROUND AND OBJECTIVES: Wide variability exists in the amount of regional anesthesia practice to which residents are exposed during training. The number of attempts at various blocks before a trainee becomes proficient at performing these regional anesthetic techniques is not known. This study addresses the question: What is the minimum number of blocks a resident must perform to reach consistency during training in these techniques?

METHODS: Every regional anesthetic technique attempted by all beginning CA-1 anesthesiology residents (n = 7) during their first 6 months of training (July 1993 to December 1993) were recorded on a daily basis. Nonregional anesthetic techniques attempted were recorded for comparison. The objective measures used to define the degree of success were obtaining cerebrospinal fluid during attempted spinal anesthesia, subsequent anesthetic block during epidural placement, and detection of end-tidal carbon dioxide for endotracheal intubation.

RESULTS: An average of 77 +/- 9 epidural anesthetics, 44 +/- 6 spinal anesthetics, and 86 +/- 13 endotracheal intubations were attempted during the 6 months of training. The learning curves for each technique are of similar shape. Residents show significant (P < .05) improvement over baseline after 20 spinal and 25 epidural anesthetics, but a 90% success rate is not reached and maintained until 45 spinal and 60 epidural anesthetics are performed.

CONCLUSIONS: Approximately 20-25 procedures each are necessary before improvement in the techniques of spinal and epidural anesthesia is demonstrated by residents in training. If a 90% success rate is desired, 45 and 60 attempts at spinal and epidural anesthesia, respectively, may be necessary.