Impact of an acute surgical unit on patient outcomes in South Australia

Compared with traditional (Trad) systems of managing emergency surgical presentations, the acute surgical unit (ASU) model provides an on-site registrar, on-call surgeon and dedicated emergency theatre, 24 h/day. To date, there have been no Australasian ASU studies of >3000 patients, nor from South Australia.

A retrospective historical control study compared the outcomes of adults admitted to the Lyell McEwin Hospital in the Trad (1 February 2010 to 31 July 2012) and ASU periods (1 August 2012 to 31 January 2015), who underwent an emergency general surgical procedure.

A total of 4074 patients met inclusion criteria; 1688 and 2386 patients during the Trad and ASU periods, respectively. The cohorts were not significantly different in median age, gender or American Society of Anesthesiologists scores. Compared with the Trad period, improved median time from emergency department referral to theatre start (19.4 h versus 17.9 h, P < 0.0001) and median length of stay (2.32 days versus 2.06 days, P < 0.0001) were observed during the ASU period. The proportion of procedures performed in-hours was similar (77.9% versus 79.6%, P = 0.18). Secondary outcomes of rates of intensive care unit admission, emergency department representation within 30 days, in-hospital mortality and 1-year all-cause mortality were unchanged.

Institution of an ASU was associated with decreased time from referral to theatre and reduced length of stay. The proportion of cases performed in-hours did not change. This may be related to the high Trad period rate and increased workload. These findings represent the largest Australasian study of an ASU and support the current model of care.