Prospective, Randomized Trial of Alerting to Extended Hypotensive Exposures on Long-Term Outcome Following Adult Non-Cardiac Surgical Procedures: The SLUScore™ Trial

Background:

We recently identified a significant association of postoperative morbidity and 30-day mortality with the concept of "hypotensive exposures" during anaesthesia. Specifically, we found in approximately 160,000 patients from 3 institutions (Cleveland Clinic, Vanderbilt University and Saint Louis University) that roughly every third adult patient undergoing a non-cardiac procedure under anaesthesia experienced twice the 30-day all-cause mortality portended by extended cumulative periods of less than normal intraoperative blood pressure. This association was independent of co-morbidity (Charlson Co-morbidity index), causing the same relative increase in mortality in "healthy" as in "sick" patients. A new method was introduced to quantify hypotensive exposures in form of a novel risk score called the SLUScore™, a score with values from ranging from 0 (no hypotensive exposure) to a maximum of 31 (the maximal number of exposures exceeded of a certain risk-based set of limits for time accumulated at a mean arterial blood pressure below thresholds between 75 and 45 mm Hg), with each increment of the SLUScore™ portending an equivalent 5% increase in 30-day postoperative mortality.

Hypothesis:

We test the hypothesis that alerting the anaesthesia care team to progressive hypotensive exposures (a progressive increase in their SLUScore™) improves 30-day survival. This will be tested in a prospective, randomised trial.

Methods and Design: