Effects of organizational change in the ICU on high-risk surgical patients: a comparison of open and closed formats

Introduction

In 2000 the ICU in a teaching hospital in the Netherlands changed from open to closed format. In this retrospective study, outcomes of high-risk surgical patients before and after the organizational change were compared.

Methods

From 1990 to 2004, all surgical patients were prospectively collected in a database containing information about the type of surgery, use of the ICU, length of hospital stay, complications, and mortality. Multivariate logistic regression was used on these data to develop a risk prediction model for mortality. The model consisted of the variables acute hospital admission, acute surgery, severity of surgery and age. Severity of surgery was based on a classification of surgical operations used in teaching hospitals in the Netherlands, scoring operations as one to seven points. More than three points was defined as severe. Age was divided into quartiles. Points were scored per variable. In total, six points could be scored: acute admission, acute surgery and severe surgery received one point. Age scored zero to three points. A total score of four points or more was defined as high risk. The model was validated through cross-validation. The area under the receiver operating characteristics curve was 0.9. ICU use, morbidity and mortality before and after the change from open to closed format were retrospectively evaluated.

Results

Two groups were defined: Group A: high-risk surgical patients in the ICU in 1996 and 1997 (open format, n = 230) and Group B: high-risk surgical patients in the ICU in 2003 and 2004 (closed format, n = 228). The primary outcome was inhospital mortality. Secondary outcomes were inhospital morbidity and length of ICU stay. The groups were comparable in age, gender and type of surgery.

Mortality of the ICU patients was 25.4% in Group A and 15.9% in Group B (P < 0.01, 95% CI = 2.5 to 17.3). This was a relative change of 37.6%. Morbidity was 48.3% in Group A and 46.3% in Group B. The average length of ICU stay was 2.5 days in Group A, and 4.8 days in Group B (P = 0.001).

Conclusion

Changing an ICU organization to a closed format reduces mortality in high-risk surgical patients, without affecting morbidity.