Correlating Brain Tissue Oxygen and Regional Cerebral Oximetry

NCT ID: NCT03128957

Last Updated: 2022-09-01

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 12 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-06-29
• Study Completion Date: 2021-06-22

Brief Summary

Controversy surrounds the use of regional cerebral oximetry (rSO2) as a measure of true cerebral oxygenation because of extracranial signal contamination and unmeasured confounding of cerebral a:v ratio. The measurement of brain tissue oxygen (PbrO2) has been used in routine neurosurgery and has been shown to reliably demonstrate cerebral hypoxia following severe head injury. It is the most direct measure of cerebral oxygenation. Here, we test the hypothesis that there is a correlation between PbrO2 and rSO2 under conditions of varying inspired oxygen fraction and the varying partial pressure of carbon dioxide in arterial blood in uninjured, normal human brain.

Patients who are scheduled for elective removal of secondary cerebral metastases under general anesthesia will be recruited following written informed consent obtained by a study team member during their preoperative evaluation. BIS and rSO2 optodes will be applied, before induction of anesthesia, by a single researcher on both sides of the patient's forehead, as recommended by the manufacturer. General anesthesia will be maintained by total intravenous anesthesia (TIVA) with a combination of propofol (80-150 mcg/kg/min) and remifentanil (0.05-0.1 mcg/kg/min) targeted to a Bispectral Index range 40-60 (BIS; Covidien, Boulder, CO). Following craniotomy, the LICOX probe will be placed under direct vision into an area of normal brain within the tumor excision canal by the attending neurosurgeon. During a pause in surgery FIO2 and minute ventilation will be sequentially adjusted to achieve the following pairs of ventilation set points: 1) FIO2 0.3 and paCO2 30mmHg, 2) FIO2 1.0 and paCO2 40mmHg. After ≥5 minutes at each set point FIO2, PaCO2, rSO2 and PbrO2 will be recorded as a "snap-shot".

A sample size of 15 achieves an 80% power with a one-sided type I error of 5% to detect a positive correlation of 0.6 (from the null hypothesis of no correlation) between changes in PbrO2 and changes in rSO2 subsequent on alterations made in ventilation strategy. Correlation will be measured using Pearson's Correlation. P values < 0.05 will be considered statistically significant.

Conditions

Stroke

Study Design

• Allocation Method: NA
• Intervention Model: SEQUENTIAL
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Varying cerebral oxygenation with varying ventilation

Compare oxygenation under conditions of varying ventilation strategy. Low end tidal CO2/Low inspired oxygen vs High end tidal CO2/high inspired oxygen

Group Type: EXPERIMENTAL

IVOS cerebral oximeter

Intervention Type: DEVICE

Measuring percutaneous cerebral oxygenation secondary to changing end tidal carbon dioxide and inspired oxygen fraction.

Licox cerebral oxygenation monitor

Intervention Type: DEVICE

Measuring tissue cerebral oxygenation secondary to changing end tidal carbon dioxide and inspired oxygen fraction.

Cerebral oxygenation

Intervention Type: OTHER

Measuring cerebral oxygenation with varying ventilation strategy

Interventions

IVOS cerebral oximeter

Measuring percutaneous cerebral oxygenation secondary to changing end tidal carbon dioxide and inspired oxygen fraction.

Intervention Type: DEVICE

Licox cerebral oxygenation monitor

Measuring tissue cerebral oxygenation secondary to changing end tidal carbon dioxide and inspired oxygen fraction.

Intervention Type: DEVICE

Cerebral oxygenation

Measuring cerebral oxygenation with varying ventilation strategy

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Patients who are scheduled for elective removal of secondary cerebral metastases under general anesthesia.

Exclusion Criteria

• Patients will be excluded if they refuse to give consent, have evidence of elevated intracranial pressure on preoperative CT scan, have coagulopathy, are taking therapeutic agents known to increase bleeding risk, have a history of cardiovascular disease, cerebrovascular disease, suffer from respiratory failure, or are not fluent English speakers.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Michigan

OTHER

Sponsor Role: lead

Responsible Party

Paul Picton

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Paul Picton, MB ChB

Role: PRINCIPAL_INVESTIGATOR

University of Michigan

Locations

University of Michigan

Ann Arbor, Michigan, United States

Countries

United States

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

HUM00105648

Identifier Type: -

Identifier Source: org_study_id