Acute myocardial infarction in Doncaster. I. Estimating size of coronary care unit.

A "no refusal" coronary care service (for one year) was offered to a selected sample of 10 general practices (total list 74,657). The patients were admitted to a three-bedded unit in Doncaster Royal Infirmary and data were collected to enable estimation of the size of unit necessary to serve the whole population in the area (census estimate 268,560; total G.P. list 315,811). This estimation was based on:1. The frequency of admission to hospital of suspected acute myocardial infarction in one year, estimated at 978 from the total population.2. The average duration of stay in the unit, which was 2.45 days.3. The distribution of observed occupancy was approximately Poissonian.From these the average expected bed occupancy was calculated as 6.56 and reference to probability tables gave the frequency of overload for different numbers of beds provided. The incidence of acute myocardial infarction in the area is estimated at 275 per 100,000 per annum, on calculations based on the practice list size, and at 323 per 100,000 per annum, on calculations based on census figures.