Background Emergency department (ED) crowding causes prolonged waiting times.

Objective To evaluate the potential benefit of introducing clinical assistants to a busy and crowded ED.

Methods This was a retrospective cohort study at an urban, academic tertiary medical centre. We introduced one clinical assistant to each ED shift. The main task of clinical assistants was managing the flow of incoming ED patients. The case group consisted of all adult non-trauma emergency patients during the case period from 1 September to 30 November 2008. The first control group consisted of all adult non-trauma emergency patients between 1 June and 31 August 2008 and the second control group consisted of all patients treated between 1 September and 30 November 2007. The primary outcome was the ‘waiting time’, defined as the time from triage to the time of the first medical order entered into the computer system. The secondary outcome was the number of adult non-trauma emergency patients who left the ED without being seen.

Results There were 12 257 cases and 25 950 controls. The mean and median waiting times were significantly shorter in the case group. The mean waiting time of the case group was 20.86 min, which was 4.51 min (17.8%) shorter than that of the first control group and 7.41 min (26.2%) shorter than that of the second control group. The median waiting time of the case group was also significantly shorter than those of the control groups. The number of the patients who left without being seen was significantly smaller in the case period.

Conclusions In a busy and crowded ED, the introduction of clinical assistants to an existing emergency health service effectively reduces patient waiting times and decreases the number of patients leaving without being seen.