Cerebral Flow-metabolism Coupling During Adult Surgery

Summary

The brain is a highly active organ that requires a large blood flow to function properly. Normally, blood flow is tightly linked to the brain's energy demands. However, during surgery, anesthesia can affect this relationship in different ways. Some types of anesthesia can decrease blood flow to the brain, while others can increase it. Anesthesiologists need to be careful to maintain adequate blood flow to the brain during surgery, especially when blood pressure drops. Drugs may be used to increase blood pressure, but some of these drugs can also affect blood flow to the brain. It is still unclear how to best maintain blood flow to the brain during surgery and how different types of anesthesia and drugs affect this process.

The study aims to assess the clinical utility of a new technique that uses light-based neuromonitoring to measure changes in cerebral blood flow and metabolism. The investigators will recruit 80 adult patients undergoing surgery under general anesthesia and randomize them into one of four groups to evaluate the effects of different anesthetic agents and vasopressors on brain hemodynamics and metabolism. The study will include patients over 18 years of age with no history of neurological conditions, substance abuse, or contraindications to cerebral oximetry devices or specific anesthetic agents. The patients will receive standard anesthesia care and be monitored with our light-based neuromonitoring system. This study aims to demonstrate the device's ability to detect changes in cerebral hemodynamic parameters related to anesthesia induction and systemic hypotension. This study will also evaluate the effects of anesthetic maintenance agents and vasopressors on cerebral hemodynamics and neurovascular coupling.

Conditions

• Anesthesia

Interventions

DRUG

Propofol

Patient will receive propofol as their maintenance agent during surgery. The typical dose is 150-200 mg/kg/min.

DRUG

Sevoflurane

Patient's anesthesia will be maintained with 1 MAC of sevoflurane during surgery.

DRUG

Ephedrine

The patient will receive ephedrine infusion as the primary vasopressor of choice. The typical dose of ephedrine infusion is 10-50 mg/hr (dilution 2 mg/ml).

DRUG

Phenylephrine

Patient will receive phenylephrine infusion as the primary vasopressor of choice. The typical dose of phenylephrine infusion is 10-40 mcg/min (dilution 100 mcg/ml).

Sponsors & Collaborators

• Jason Chui

  lead OTHER

Principal Investigators

• Jason Chui, MD · Western University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

FACTORIAL

Eligibility

Min Age

19 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-10-03

Primary Completion

2025-12-31

Completion

2025-12-31

Countries

• Canada

Study Locations