Human error identification: an analysis of myringotomy and ventilation tube insertion

To use a human reliability assessment tool to identify commonly occurring errors during myringotomy and ventilation tube (VT) insertion and to quantify the likelihood of error occurrence.

Error-free task analysis for myringotomy and VT insertion was defined at the outset. Fifty-five consecutive myringotomy and VT insertion procedures were videotaped. The operator was either the senior author (S.S.M.H.) or a trainee in the specialist registrar or senior house officer grade. Three assessors (M.-L.M., M.S.W.L, and S.S.M.H.) blinded to operator identity independently evaluated each procedure. Interobserver agreement was calculated (kappa values).

Twelve potential error types were identified. A total of 87 errors were observed in 55 procedures. In 53% of procedures (n = 29) multiple errors were identified. Seven percent of procedures (n = 4) were error free. The 4 most frequent errors identified were (1) failure to perform a unidirectional myringotomy incision (n = 37; 43%); (2) multiple attempts to place VT (n = 14; 16%); (3) multiple attempts to complete the myringotomy (n = 11; 13%); and (4) magnification setting too high (n = 11; 13%). The human error probability was 0.13. Interobserver agreement as expressed by kappa statistics was high.

Human error identification in this most common of otologic procedures is crucial to future error avoidance. Eliminating the 2 most common errors in this model will halve the human error probability. Extending the role of error analysis to error-based teaching as an educational tool has potential.