Investigating the effectiveness of critical care outreach services: a systematic review

Objective: We explored the impact of critical care outreach activity on patient and service outcomes and aimed to contribute to developing a typology of critical care outreach services. Design: Following a sample search of Medline 15 relevant electronic databases were systematically searched from 1996 to 2004. Searches for publications from nine key authors and citations of eight key articles were performed. Hand searches of journals, bibliographies of reports and review articles, and conference abstracts were conducted. Relevant experts were contacted. A further two studies published after the review date were also included. Two reviewers assessed studies for inclusion, conducted quality assessment and extracted data. Data were synthesised using narrative techniques. Measurements and results: Seventeen papers and six brief reports were selected for inclusion from a list of 1,760 titles. As anticipated with a relatively new service such as critical care outreach, there were few controlled trials. There were two randomised controlled trials, 16 uncontrolled before and after studies, three quasi-experimental studies, one controlled before and after study and one post-only controlled study. The most frequent outcomes measured were mortality, cardiac arrest, unplanned critical care admissions from wards, length of stay, and critical care readmission rates. Conclusions: Although improvements in patient outcomes were found, the evidence in this review is insufficient to demonstrate this conclusively. The many differences in service delivery do not permit identification of service typology. Our findings point to a need for more comprehensive research of this expanding service in the United Kingdom.