Intraoperative hypotension and neurological outcomes

Area of Science:

• Anesthesiology
• Neurology
• Critical Care Medicine

Background:

• Intraoperative hypotension (IOH) can lead to cerebral hypoperfusion and postoperative neurological injury.
• Cerebral blood flow (CBF) is influenced by blood pressure, autoregulation, and confounding factors.
• Current definitions and thresholds for IOH lack consensus regarding neurological complications.

Purpose of the Study:

• To refine the definition of intraoperative hypotension (IOH).
• To evaluate the impact of IOH on neurological outcomes.
• To review recent literature on IOH and its association with neurological injury.

Main Methods:

• Literature review of recent studies on intraoperative hypotension and neurological outcomes.
• Analysis of studies investigating blood pressure thresholds for IOH.
• Examination of factors influencing cerebral blood flow (CBF) and autoregulation.

Main Results:

• No definitive IOH threshold is established for neurological complications like stroke or delirium.
• Confounding factors and variability in cerebral pressure autoregulation complicate the assessment of IOH's impact.
• Cohort studies, the primary evidence, have limitations in establishing causality.
• Maintaining target blood pressure guided by regional cerebral oxygen saturation (rScO2) or autoregulation appears linked to fewer postoperative neurological complications.

Conclusions:

• Intraoperative hypotension is a modifiable risk factor for neurological outcomes, despite lacking a defined threshold.
• Optimizing blood pressure management is crucial for improving neurological outcomes.
• Monitoring rScO2 or cerebral pressure autoregulation is recommended for guiding blood pressure management.