Case-controlled study of critical care or surgical ward care after elective open colorectal surgery.

BACKGROUND: Evidence for the benefit of critical care after surgery is limited. This study assessed the value of immediate admission to the critical care unit (CCU) after open colorectal surgery.
METHODS: Patients aged over 45 years were screened with a cardiopulmonary exercise test to determine their anaerobic threshold. Less fit patients defined by an anaerobic threshold below 11 ml oxygen per kg per min were assigned to either critical care or surgical ward care. Those with an anaerobic threshold of 11 ml oxygen per kg per min or above were assigned to ward care. The outcome measure was the number of cardiac events.
RESULTS: Of 153 patients who underwent exercise testing, 55 had an anaerobic threshold of at least 11 ml oxygen per kg per min (ward care) and 98 had a threshold of less than 11 ml oxygen per kg per min, of whom 39 were allocated to ward care and 51 to critical care. Median length of CCU stay was 31 (range 5-46) h. More cardiac events occurred in patients allocated to ward care (7 of 39) than in those allocated to critical care (0 of 51): absolute difference 18 (95 per cent confidence interval 10 to 26) per cent (P = 0·002). There were no cardiac events in patients with an anaerobic threshold of 11 ml oxygen per kg per min or higher.
CONCLUSION: Patients with an anaerobic threshold of at least 11 ml oxygen per kg per min and those with a threshold below 11 ml oxygen per kg per min managed in the CCU had fewer cardiac events.