prospective trial of alerting to extended hypotensive exposures on long-term outcome after surgery

Conditions: Anesthesia; Hypotension

Summary: patients undergoing anesthesia for non-cardiac surgery will be randomized to either having their anesthesia team alerted or kept blinded to extended periods of less than normal blood pressure with the goal of studying if providing these alerts leads to improved outcome after surgery (lower risk of death or complication in the days and weeks following surgery).

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: a novel clinical decision support system (acg-anesthesia by talis clinical, llc) will be used to alert anaesthesia care team members to patients' sluscores™ in near real time (within 1 minute of documented exposures). at the time of transition from a sluscore™ of 0 to 1 (occurring in approximately every third anaesthetic), patients will be automatically randomized by the acg-anesthesia system to either alert or no alert (blinded) status with the intent of raising awareness on the part of the anaesthesia care team in the alert group of the occurrence of extended hypotensive exposures and their associated risk, allowing the team to render its best clinical judgment to initiate interventions aimed at bringing patients out of progressive hypotensive states. with one interim analysis planned after two years, a total of 56,248 patients are projected to be enrolled over a 4-year period for this trial to be powered to detect a 0.3% absolute reduction in 30-day mortality, by saving at least 50 lives in the alert group after two years (two-sided p\<0.016) or at least 70 lives (two-sided p\<0.019) at the conclusion of the trial.

Eligibility criteria:
inclusion criteria: * any adult patient presenting for any type of non-cardiac procedure performed under any type of anesthesia exclusion criteria: * pediatric patients (\< 18 yrs of age) * obstetric patients

Keywords: anesthesia hypotension