Intraoperative hypotension is associated with acute kidney injury (AKI). Clinicians thus frequently use vasopressors, such as norepinephrine, to maintain blood pressure. However, vasopressors themselves might promote AKI. We sought to determine whether both intraoperative hypotension and cumulative intraoperative norepinephrine dose are independently associated with postoperative AKI in patients undergoing noncardiac surgery. This was a retrospective cohort analysis of 38 338 adult male and female patients who had noncardiac surgery. The primary outcome was AKI within the first 7 postoperative days. We performed adjusted multivariable logistic regression analysis to determine whether intraoperative hypotension (quantified as area under a mean arterial pressure [MAP] of 65 mm Hg) and cumulative intraoperative norepinephrine dose were independently associated with AKI. The median (25th percentile, 75th percentile) area under a MAP of 65 mm Hg was 0.09 (0.02, 0.22) mm Hg∗day in patients with AKI and 0.05 (0.01, 0.14) mm Hg∗day in patients without AKI (P<0.001). The cumulative intraoperative norepinephrine dose was 1.92 (0.00, 13.09) μg kg^-1 in patients with AKI and 0.00 (0.00, 0.00) μg kg^-1 in patients without AKI (P<0.001). Both the area under a MAP of 65 mm Hg (odds ratio 1.55 [95% confidence interval 1.17-2.02] per mm Hg∗day; P=0.002) and the cumulative intraoperative norepinephrine dose (odds ratio 1.02 [95% confidence interval 1.01-1.02] per μg kg^-1; P<0.001) were independently associated with AKI. Both intraoperative hypotension and cumulative intraoperative norepinephrine dose were independently associated with postoperative AKI in patients undergoing noncardiac surgery. Pending results of trials testing whether these relationships are causal, it seems prudent to avoid both profound hypotension and high norepinephrine doses in adults undergoing noncardiac surgery.

Background: Intraoperative hypotension is common in patients having non-cardiac surgery and is associated with serious complications and death. However, optimal intraoperative blood pressures for individual patients remain unknown. We therefore aim to test the hypothesis that personalized perioperative blood pressure management—based on preoperative automated blood pressure monitoring—reduces the incidence of a composite outcome of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery. Methods: IMPROVE-multi is a multicenter randomized trial in 1272 high-risk patients having elective major abdominal surgery that we plan to conduct at 16 German university medical centers. Preoperative automated blood pressure monitoring using upper arm cuff oscillometry will be performed in all patients for one night to obtain the mean of the nighttime mean arterial pressures. Patients will then be randomized either to personalized blood pressure management or to routine blood pressure management. In patients assigned to personalized management, intraoperative mean arterial pressure will be maintained at least at the mean of the nighttime mean arterial pressures. In patients assigned to routine management, intraoperative blood pressure will be managed per routine. The primary outcome will be a composite of acute kidney injury, acute myocardial injury, non-fatal cardiac arrest, and death within 7 days after surgery. Discussion: Our trial will determine whether personalized perioperative blood pressure management reduces the incidence of major postoperative complications and death within 7 days after surgery compared to routine blood pressure management in high-risk patients having major abdominal surgery. Trial registration: ClinicalTrials.gov NCT05416944. Registered on June 14, 2022.

BACKGROUND: Haemodynamic monitoring and management is a mainstay of peri-operative anaesthetic care. OBJECTIVE: To determine how anaesthesiologists measure and manage blood pressure and cardiac output, and how they guide fluid administration and assess fluid responsiveness in patients having noncardiac surgery. DESIGN: Web-based survey. SETTING: Survey among members of the European Society of Anaesthesiology and Intensive Care (ESAIC) in October and November 2021. PARTICIPANTS: ESAIC members responding to the survey. MAIN OUTCOME MEASURES: Respondents’ answers to 30 questions on haemodynamic monitoring and management, and fluid therapy. RESULTS: A total of 615 fully completed surveys were analysed. Arterial catheters are usually not placed before induction of general anaesthesia (378/615; 61%) even when invasive blood pressure monitoring is planned. Mean arterial pressure (532/615; 87%) with lower intervention thresholds of 65 mmHg (183/531; 34%) or 20% below pre-operative baseline (166/531; 31%) is primarily used to guide blood pressure management. Cardiac output is most frequently measured using pulse wave analysis (548/597; 92%). However, only one-third of respondents (almost) always use cardiac output to guide haemodynamic management in high-risk patients (225/582; 39%). Dynamic cardiac preload variables are more frequently used to guide haemodynamic management than cardiac output [pulse pressure variation (almost) always: 318/589; 54%]. Standardised treatment protocols are rarely used for haemodynamic management (139/614; 23%). For fluid therapy, crystalloids are primarily used as maintenance fluids, to treat hypovolaemia, and for fluid challenges. The use of 0.9% saline and hydroxyethyl starch has declined over the last decade. The preferred methods to assess fluid responsiveness are dynamic preload variables and fluid challenges, most commonly with 250 ml of fluid (319/613; 52%). CONCLUSION: This survey provides important information how anaesthesiologists currently measure and manage blood pressure and cardiac output, and how they guide fluid administration in patients having noncardiac surgery.

Hypotension after induction of general anaesthesia is common in high-risk patients having noncardiac surgery. Anaesthesiologists often give manual boluses of vasopressors repeatedly to maintain blood pressure during induction of general anaesthesia, including the fast-acting vasopressor norepinephrine which has a short half-life. We tested the hypothesis that giving norepinephrine continuously during induction of general anaesthesia, compared with giving it as repeated manual boluses, improves blood pressure stability in high-risk noncardiac surgery patients. In this single-centre trial, 72 participants undergoing noncardiac surgery were randomised to continuous norepinephrine infusion or manual bolus norepinephrine administration during induction of general anaesthesia. Blood pressure was monitored continuously with an arterial catheter. The primary endpoint was blood pressure stability, quantified as the generalised average real variability of mean arterial pressure within 15 min after starting induction of general anaesthesia. A total of 71 participants completed the study (mean [range] age: 66 [47-86] y; 48% female). The mean (standard deviation) generalised average real variability of mean arterial pressure was 19 (6) mm Hg min^-1 in 36 participants assigned to continuous norepinephrine infusion, compared with 25 (7) mm Hg min^-1 in 35 participants assigned to manual bolus norepinephrine administration (P<0.001). Giving norepinephrine continuously during induction of general anaesthesia, compared with giving it as repeated manual boluses, improved blood pressure stability in higher-risk individuals undergoing noncardiac surgery. NCT05997303.