Elective Craniotomy, General Anaesthesia, Neurosurgery
Conditions
Brief summary
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.
Interventions
DEVICENIRS measurements on skin, skull and dura
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.
DRUGPhenylephrine's effect on brain oxygenation
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.
DRUGNormal vs. high inspired oxygen
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.
Sponsors
University Hospital Bispebjerg and Frederiksberg
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| ScO2 (NIRS-measured cerebral oxygen saturation) | During surgical procedure | Difference in ScO2 between dura and skin (Primary analysis for substudy 1) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| PBrO2 (Partial pressure of brain tissue oxygen) | During surgical procedure | Cerebral oxygenation, measured by a Clark-electrode (Licox (R)) (Primary outcome measure for substudy 2) |
| ScO2 (NIRS-measured cerebral oxygen saturation) | Measurements will be performed as the surgeon exposes the skull. | Difference in ScO2 between dura and skull, and between skull and skin (this will be the secondary analyses of substudy 1) |
| ScO2 (NIRS-measured cerebral oxygenation) | NIRS signal is obtained continuously during the Phenylephrine intervention | NIRS-signal during Phenylephrine intervention (this will be the secondary outcome of substudy 2) |
Countries
Denmark
Outcome results
None listed