Neuro-Ox 2018: Assessment of Cerebral Oxygenation Under Three Clinically Relevant Conditions

University Hospital Bispebjerg and Frederiksberg18 enrolled

Overview

This is a prospective observational study, consisting of 3 substudies carried out during elective neurosurgery under general anaesthesia. Each participant will take part in all 3 substudies. First, the capability of Near Infra Red Spectroscopy (NIRS) to measure the brain oxygenation is examined. A NIRS-electrode is placed on forehead skin, on the skull, and on dura. Secondly, a small dose of Phenylephrine is given, and the brain oxygenation is measured by a Clark-electrode and a NIRS-electrode, to see how Phenylephrine affects these measurements. In the third substudy, the brain oxygenations' (NIRS and Licox) response to an inspired oxygen fraction of 0.30 vs. 0.80 is investigated.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Neurosurgery Elective Craniotomy General Anaesthesia

Interventions

NIRS measurements on skin, skull and duraDEVICE

During a neurosurgical procedure, we will measure the brain oxygenation with a NIRS-electrode, first on forehead skin, then on the skull and finally directly on dura.

Phenylephrine's effect on brain oxygenationDRUG

With a Clark-electrode (Licox(R)) in the white matter and a NIRS-electrode on the forehead skin, we will give a small dose (0.1 mg iv.) Phenylephrine.

Normal vs. high inspired oxygenDRUG

By the end of the neurosurgical procedure, still with a Clark-electrode in the white matter and a NIRS-electrode on forehead skin, we will change the inspired oxygen fraction from 0.3 to 0.8.

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Adult (\>18 years) patients * Elective craniotomy Exclusion Criteria: * Repeat craniotomy * Preoperative hypotension (defined as systolic blood pressure below 110 mmHg) * Preoperative hypoxia (defined as peripheral oxygen saturation (SpO2) \< 90% without oxygen supplementation before surgery) * No negative pregnancy test for women \<50 years.

Locations (1)

Rigshospitalet

Copenhagen, Denmark

Outcomes

Primary Outcomes

ScO2 (NIRS-measured cerebral oxygen saturation)

Difference in ScO2 between dura and skin (Primary analysis for substudy 1)

Time frame: During surgical procedure

Secondary Outcomes

PBrO2 (Partial pressure of brain tissue oxygen)

Cerebral oxygenation, measured by a Clark-electrode (Licox (R)) (Primary outcome measure for substudy 2)

Time frame: During surgical procedure

PBrO2 (Partial pressure of brain tissue oxygen)

Cerebral oxygenation during inspired oxygen fraction 0.80 vs. 0.30 (Primary outcome for substudy 3)

Time frame: 'Normoxia' is induced with FiO2 = 0.30 for 5 minutes, and then changed to 'Hyperoxia' with FiO2 = 0.80 for the subsequent 5 minutes, while registering the Licox-signal.

ScO2 (NIRS-measured cerebral oxygen saturation)

Difference in ScO2 between dura and skull, and between skull and skin (this will be the secondary analyses of substudy 1)

Time frame: Measurements will be performed as the surgeon exposes the skull.

ScO2 (NIRS-measured cerebral oxygenation)

NIRS-signal during Phenylephrine intervention (this will be the secondary outcome of substudy 2)

Time frame: NIRS signal is obtained continuously during the Phenylephrine intervention

Data from ClinicalTrials.gov

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