Multicentre evaluation of the impact of the introduction of outreach services in the United Kingdom

Background

Critical care outreach services (CCOS) have been introduced in the United Kingdom with aims to: avert or ensure timely admission to critical care; enable discharge from critical care; and share skills with ward staff. We aimed to assess the impact of the introduction of CCOS at the critical care unit level, as characterised by the case mix, outcome and activity of critical care unit admissions.

Methods

An interrupted time-series analysis was carried out using data from 108 units participating in the Case Mix Programme that had completed a survey on CCOS provision. Individual patient-level data were collapsed into monthly time series for each unit (panel data). Population-averaged panel-data models were fitted using a generalised estimating equation approach. Various outcomes reflecting the stated aims of CCOS were considered for three groups of admissions: all admissions to the unit; admissions from the ward; and unit survivors discharged to the ward. The primary exposure variable was the presence of a formal CCOS with secondary exposures of CCOS activities, coverage and staffing, identified from the survey data.

Results

Of 108 units in the analysis, 79 (73%) had a formal CCOS introduced between 1996 and 2004. For admissions from the ward, the presence of a CCOS was associated with significant reductions in: the proportion of admissions receiving cardiopulmonary resuscitation during the 24 hours prior to admission (odds ratio 0.84, 95% confidence interval 0.73–0.96); the proportion of admissions between 22:00 and 06:59 (0.91, 0.84–0.97); and the mean ICNARC physiology score (absolute reduction 1.2, 0.3–2.1). No significant effects of CCOS on outcomes including hospital mortality and readmission to critical care were identified for patients discharged to the ward.

Interpretation

The results of this study were mixed. While some differences in the characteristics of patients admitted to critical care units were found to be associated with the introduction of CCOS, there was no evidence for an impact on the outcomes of patients discharged from critical care. It was not possible to identify any clear characteristics for an optimal CCOS.