The risk of postoperative deterioration of non-cardiac surgery patients with ICU referral status who are admitted to the regular ward: a retrospective observational cohort study.

Background: Higher-risk surgical patients may not be admitted to the intensive care unit due to stable immediate post-operative status on review. The outcomes of this cohort are not well described. Our aim was to examine the subsequent inpatient course of intensive care unit -referred but not admitted surgical patients.

Methods: All patients aged ≥18 years who were referred but not admitted for post-operative management in a tertiary metropolitan intensive care unit following non-cardiac surgery between 1/7/2017 and 30/6/2018 were eligible for inclusion in this retrospective observational cohort study. Primary outcome was Medical Emergency Team activation. Secondary outcomes included unplanned intensive care unit admission; length of stay; and 30-day mortality. Risk of serious complications and predicted length of stay were calculated using the National Surgical Quality Improvement Program scoring tool.

Results: Fifteen of 60 patients (25%) had a MET-call following surgery, eight (13%) patients required unplanned intensive care unit admission, with median (IQR) time to Medical Emergency Team call 9 (6-13) hours. No patients died within 30-days. There was no significant difference between mean National Surgical Quality Improvement Program predicted and actual length of stay; after adjustment, National Surgical Quality Improvement Program predicted risk of serious complications was associated with unplanned intensive care unit admission (OR [95% CI] = 1.08 [1.00-1.16], p = 0.04), although not Medical Emergency Team calls.

Conclusions: Post-operative deterioration occurs frequently, and early, in a cohort of high-risk surgical patients initially assessed as being safe for ward care. Changes to current triage models for post-operative intensive care unit admission may reduce the impact of complications in this high-risk group.