Mortality in a university surgical unit: what is an avoidable death?

Between January 1978 and December 1987 there were 23,557 surgical admissions to the University Surgical Unit in Southampton. During this period there were 543 deaths, an overall death per admission rate of 2.3%. During the 10-year period the number of admissions per year had risen from 1884 in 1978 (death per admission = 3.6%) to 3467 in 1987 (death per admission rate = 1.7%). At the monthly audit meeting an attempt was made to classify each death as 'avoidable' or 'unavoidable'. During this 10-year period it was considered that there were 89 'avoidable' deaths. This represents an avoidable mortality rate (AMR) of 0.38%. These 'avoidable' deaths were due to a wide variety of causes and this paper discusses the lessons learnt from a review of surgical mortality and outlines how units might compare results.