Evidence Base
Hemodynamic instability during surgery is common and clinically important
During surgery, anesthesia teams continuously assess cardiovascular status using multiple physiological signals, including arterial blood pressure, heart rate and other hemodynamic parameters.
Although modern patient monitors provide extensive physiological data, identifying meaningful changes in cardiovascular state can be challenging, particularly when changes develop gradually over time.
Intraoperative hypotension is associated with adverse outcomes
A substantial body of clinical evidence has demonstrated associations between intraoperative hypotension and postoperative complications. Research has linked prolonged episodes of low blood pressure during surgery with increased risk of:
Acute kidney injury
Myocardial injury
Stroke
Increased postoperative morbidity and mortality
A systematic review and meta-analysis of more than 130,000 patients found that intraoperative hypotension was associated with increased postoperative morbidity and mortality¹
Further analyses have demonstrated associations between the duration and severity of hypotension and risks of acute kidney injury and myocardial injury following non-cardiac surgery.²
Understanding the hemodynamic picture
Blood pressure is a dynamic physiological signal. Mean arterial pressure alone does not fully describe the complex interaction between:
Cardiac output
Vascular tone
Heart rate
Arterial pressure changes
Improving visibility of hemodynamic trends may help clinicians better understand cardiovascular changes occurring throughout surgery.
Evidence is moving from association to intervention
Historically, much of the evidence around intraoperative hypotension has shown association: patients who spend longer at low blood pressure have worse outcomes.
New interventional evidence is now emerging. In the HISTAP multicentre randomised trial, high-risk hypertensive patients undergoing major abdominal surgery had fewer major postoperative organ complications when managed to a higher intraoperative blood-pressure target, supported by continuous hemodynamic monitoring and protocolized fluid therapy.³
The benefit was driven mainly by fewer cases of acute kidney injury. This supports an important clinical principle: better detection, interpretation and management of hemodynamic instability may help reduce avoidable postoperative complications in selected high-risk surgical patients.
Building evidence-based tools for perioperative care
Directed Systems develops software designed to transform physiological data into meaningful hemodynamic information, supporting anesthesia professionals in assessing cardiovascular status during surgery.
Selected Publications
Wijnberge M, Schenk J, Bulle E, et al. Association of intraoperative hypotension with postoperative morbidity and mortality: systematic review and meta-analysis. BJS Open. 2021;5(1):zraa018. doi:10.1093/bjsopen/zraa018.
Salmasi, V., Maheshwari, K., Yang, D., Mascha, E. J., Singh, A., Sessler, D.I., & Kurz, A. Relationship between Intraoperative Hypotension, Defined by Either Reduction from Baseline or Absolute Thresholds, and Acute Kidney and Myocardial Injury after Noncardiac Surgery. Anesthesiology, 2017; 126(1), 47–65.
Cecconi M, Cortegiani A, Noto A, et al. HIgh versus STAndard blood Pressure target in hypertensive high-risk patients undergoing elective major abdominal surgery: the HISTAP multicenter randomized clinical trial. Intensive Care Medicine. 2026. doi:10.1007/s00134-026-08501-7.