Background Intraoperative Hypotension (IOH) during non-cardiac surgery is a common side effect of anesthesia that is associated with acute kidney injury (AKI), myocardial injury (MI), mortality, and other adverse outcomes1,3,4. These risks increase as the duration and severity of IOH exposure increase3,4. Blood pressure is a modifiable risk factor of mortality and organ damage that can be readily treated by the anesthesia provider2 . Limiting IOH can improve patient outcomes and produce monetary savings5 . The objective of this project is to report the incidence of IOH at a large tertiary teaching hospital, and extrapolate the risks of mortality and organ damage among patients with IOH. This project also identifies IOH risk factors, and reports timing of IOH during surgery.
Methods We conducted a retrospective analysis of secondary, observational data at Providence Sacred Heart Medical Center (PSHMC) • Eligibility Criteria. Inclusion: patients \u3e18 years of age who received general anesthesia for elective non cardiac surgery from October 1, 2017 to September 30, 2018 Exclusion: cardiopulmonary bypass, emergent, cesarean & pediatric surgical populations; persons with blood pressure frequency \u3e5 minutes • Patient demographic and surgical data from electronic medical records were extracted using a REDCap data collection tool • We defined IOH according to absolute mean arterial pressure thresholds described by Wesselink et al., 20184 • Descriptive analyses were conducted to examine baseline demographics, incidence and timing of IOH in the study population • Multivariable analyses using binary logistic regression were performed to examine risk factors associated with IOH ( = 0.5) • The risks of mortality, AKI & MI associated with each IOH definition were extrapolated based upon data from a 2018 systematic review4 • This project was approved by the PSHMC Clinical Innovation and Research Council, and deemed exempt from human subjects research by Providence Health Care institutional review board
Discussion At a large tertiary teaching hospital, we found that 24% of our study population experienced IOH associated \u3e 50% increased risk of MI, while 8% and 6% of patients experienced IOH associated with a \u3e2 times greater risk for AKI and mortality, respectively. Female sex, longer case duration, and interventional radiology, cardiology, and plastics service lines were among the top IOH risk factors. 42% of IOH occurred between anesthesia induction and surgical incision, even though that time period only accounted for 19% of the intraoperative time. These findings suggest that up to one-quarter of non-cardiac surgical patients may be at elevated risk for organ damage, and as much as 6% patients may double their risk of mortality due to IOH. Given these risks, anesthesia providers should minimize IOH, and be aware of patient and surgical characteristics associated with higher IOH risk. The period between anesthesia induction and surgical incision may represent a time in which the anesthesia providers can work independently to reduce IOH exposure. Future projects should examine the utility of strategies for anesthesia providers to reduce IOH exposure in patients undergoing noncardiac surgery and reassess incidence rates.https://digitalcommons.psjhealth.org/other_pubs/1117/thumbnail.jp
