Intraoperative Hypotension and 1-Year Mortality after Noncardiac Surgery

Background:Intraoperative hypotension (IOH) is frequently associated with adverse outcome such as 1-yr mortality. However, there is no consensus on the correct definition of IOH. The authors studied a number of different definitions of IOH, based on blood pressure thresholds and minimal episode durations, and their association with 1-yr mortality after noncardiac surgery. Methods:This cohort study included 1,705 consecutive adult patients who underwent general and vascular surgery. Data on IOH and potentially confounding variables were obtained from electronic record-keeping systems. Mortality data were collected up to 1 yr after surgery. The authors used two different techniques to reduce the influence of confounding variables, multivariable Cox proportional hazard regression modeling and classification and regression tree analysis. Results:The mortality within 1 yr after surgery was 5.2% (88 patients). After adjustment for confounding, the Cox regression analysis did not show an association between IOH and the risk of dying within 1 yr after surgery (hazard ratio around 1.00 with high P values for different definitions of IOH). Additional classification and regression tree analysis identified IOH as a predictor for 1-yr mortality in elderly patients. When the blood pressure threshold for IOH was decreased, the duration of IOH at which this association was found was decreased as well. Conclusions:This observational study showed no causal relation between IOH and 1-yr mortality after noncardiac surgery for any of the definitions of IOH. Nevertheless, additional analysis suggested that for elderly patients, the mortality risk increases when the duration of IOH becomes long enough. The length of this duration depends on the designated blood pressure threshold, suggesting that lower blood pressures are tolerated for shorter durations. The effect of IOH on 1-yr mortality remains debatable, and no firm conclusions on the lowest acceptable intraoperative blood pressures can be drawn from this study.

[1]  Fredrik Granath,et al.  Mortality Within 2 Years After Surgery in Relation to Low Intraoperative Bispectral Index Values and Preexisting Malignant Disease , 2009, Anesthesia and analgesia.

[2]  Jeffrey C. Sigl,et al.  Anesthetic Management and One-Year Mortality After Noncardiac Surgery , 2005, Anesthesia and analgesia.

[3]  N. Morton,et al.  Pharmacokinetic model driven infusion of propofol in children. , 1991, British journal of anaesthesia.

[4]  H Nakagawa,et al.  Adverse effects of limited hypotensive anesthesia on the outcome of patients with subarachnoid hemorrhage. , 2000, Journal of neurosurgery.

[5]  L. Thabane,et al.  Deliberate hypotension in orthopedic surgery reduces blood loss and transfusion requirements: A meta-analysis of randomized controlled trials , 2007, Canadian journal of anaesthesia = Journal canadien d'anesthesie.

[6]  Eric Jougla,et al.  Survey of Anesthesia-related Mortality in France , 2006, Anesthesiology.

[7]  M. Pessin,et al.  Mechanisms and clinical features of posterior border-zone infarcts , 1999, Neurology.

[8]  David A. Schoenfeld,et al.  Partial residuals for the proportional hazards regression model , 1982 .

[9]  Karel G M Moons,et al.  Incidence of Intraoperative Hypotension as a Function of the Chosen Definition: Literature Definitions Applied to a Retrospective Cohort Using Automated Data Collection , 2007, Anesthesiology.

[10]  L. Hollos,et al.  Effect Site Targeted Propofol Infusion In Clinical Practice: Comparison To Diprifusor , 2000 .

[11]  C. Ranawat,et al.  Randomized trial of hypotensive epidural anesthesia in older adults. , 1999, Anesthesiology.

[12]  M. Assi,et al.  Intraoperative hypotension and prolonged operative time as risk factors for slow graft function in kidney transplant recipients , 2006, Clinical transplantation.

[13]  M. Limburg,et al.  Ischemic stroke after surgical procedures , 1998, Neurology.

[14]  C. Kalkman,et al.  The accuracy of trained nurses in pre‐operative health assessment: results of the OPEN study , 2004, Anaesthesia.

[15]  D. Reich,et al.  Association of intraoperative hypotension and pulmonary hypertension with adverse outcomes after orthotopic liver transplantation. , 2003, Journal of cardiothoracic and vascular anesthesia.

[16]  F. Harrell,et al.  Prognostic/Clinical Prediction Models: Multivariable Prognostic Models: Issues in Developing Models, Evaluating Assumptions and Adequacy, and Measuring and Reducing Errors , 2005 .