Intraoperative hypotension and neurological outcomes

Abstract

Purpose of review Intraoperative hypotension (IOH) may render patients at a risk of cerebral hypoperfusion with decreasing cerebral blood flow (CBF), and lead to postoperative neurological injury. On the basis of the literature in recent years, this review attempts to refine the definition of IOH and evaluate its impact on neurological outcomes. Recent findings Although both absolute and relative blood pressure (BP) thresholds, with or without a cumulative period, have been used in collective clinical studies, no definitive threshold of IOH has been established for neurological complications, including perioperative stroke, postoperative cognitive disorder and delirium. The CBF is jointly modulated by multiple pressure processes (i.e. cerebral pressure autoregulation) and nonpressure processes, including patient, surgical and anaesthesia-related confounding factors. The confounding factors and variability in cerebral pressure autoregulation might impede evaluating the effect of IOH on the neurological outcomes. Furthermore, the majority of the evidence presented in this review are cohort studies, which are weak in demonstrating a cause--effect relationship between IOH and neurological complications. The maintenance of target BP based on the monitoring of regional cerebral oxygen saturation (rScO2) or cerebral pressure autoregulation seems to be associated with the decreased incidence of postoperative neurological complications. Summary Despite the lack of a known threshold value, IOH is a modifiable risk factor targeted to improve neurological outcomes. Ideal BP management is recommended in order to maintain target BP based on the monitoring of rScO2 or cerebral pressure autoregulation.

Effect of Deliberate Hypotension on Regional Cerebral Oxygen Saturation During Functional Endoscopic Sinus Surgery: A Randomized Controlled Trial

“…However, a lower MAP can decrease cerebral blood flow (CBF) and thus increase the risk of cerebral hypoperfusion, eventually leading to postoperative neurological injuries, such as stroke, postoperative delirium (POD), and POCD ( 11 ). A large retrospective cohort analysis of 7,457 patients undergoing cardiac surgery showed a strong association between continuous MAP below 64 mmHg and postoperative stroke during cardiopulmonary bypass, and the severity and duration of hypotension were closely connected with the risk of stroke after surgery ( 12 ).…”

Association Between Intraoperative Arterial Hypotension and Postoperative Delirium After Noncardiac Surgery: A Retrospective Multicenter Cohort Study

“…Analyses were adjusted for a priori-defined potential confounding variables based on available literature and clinical plausibility. 10,19,24 Potential confounding variables included patient demographics and comorbidities such as age, sex, body mass index (BMI), ASA physical status classification, diabetes mellitus, arterial hypertension, peripheral vascular disease, cerebrovascular disease, patent foramen ovale, smoking, depression, schizoaffective disorders, neurocognitive impairment, history of drug and alcohol abuse, as well as ischemic stroke or transient ischemic attack within 1 year before surgery. We further adjusted analyses for preoperative medications including benzodiazepines and antipsychotics as well as for intraoperative anesthesia-related factors and markers of procedural severity, including the admission type, emergency status, duration of surgery, high-risk surgery (transplant, general, vascular, or neurosurgery), and work relative value units (surgical work relative value units based on Current Procedural Terminology [CPT] codes).…”

“…[7][8][9] There are equivocal data on the association between intraoperative blood pressure management and the incidence of postoperative delirium. [10][11][12][13] A critical decrease in cerebral perfusion pressure, for example, during cardiac arrest is an independent risk factor for delirium. Similarly, intraoperative arterial hypotension compromises local perfusion pressures and reduces brain oxygenation.…”

Anesthetic Management for Spine Surgery in a Patient with Left Internal Carotid Artery Occlusion and Penetrating Aortic Ulcer: A Case Report

“…For patients with carotid artery stenosis, it is important to optimize brain perfusion and minimize myocardial stress [4]. Because intraoperative hypotension can worsen neurological outcomes, proper blood pressure management is required [5]. Several factors are known to decrease cerebral oxygenation during anesthesia.…”