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. 2023 Jan;67(1):57-65.
doi: 10.1111/aas.14149. Epub 2022 Oct 4.

Impact of hyperoxia and phenylephrine on cerebral oxygenation: An experimental clinical study

Sofie S Pedersen  1   2 , Christian S Meyhoff  1   2 , Markus Harboe Olsen  3 , Zara R Stisen  1   2 , Anton Lund  3 , Kirsten Møller  3   4 , Jane Skjøth-Rasmussen  5 , Finn B Moltke  1 , Martin Kryspin Sørensen  3
Affiliations

Impact of hyperoxia and phenylephrine on cerebral oxygenation: An experimental clinical study

Sofie S Pedersen et al. Acta Anaesthesiol Scand. 2023 Jan.

Abstract

Background: Oxygen supply to the brain is of special importance during intracranial surgery because it may be compromised by intracranial pathology. A high arterial blood pressure (mean arterial pressure above 80 mmHg) and a high arterial oxygen tension (PaO2 above 12 kPa) is therefore often targeted in these patients, when for example intracranial pressure is increased or when a mass effect on brain tissue from a tumour is present, and it is pursued by administering vasopressors such as phenylephrine and by increasing inspiratory oxygen fraction (FiO2 ). However, whether these interventions increase cerebral oxygenation remains uncertain. We aimed to investigate the effect of hyperoxia and phenylephrine on brain tissue oxygen tension (PbtO2 ) in patients undergoing craniotomy.

Methods: In this experimental study, we included 17 adult patients scheduled for elective craniotomy. After securing a stable baseline of the oxygen probe, PbtO2 was measured in white matter peripherally in the surgical field during general anaesthesia. Primary comparisons were PbtO2 before versus after an increase in FiO2 from 0.30 to 0.80 as well as before versus after a bolus dose of phenylephrine (0.1-0.2 mg depending on patient haemodynamics). Data were analysed with the Wilcoxon signed rank test.

Results: We obtained complete data sets in 11 patients undergoing the FiO2 increase and six patients receiving the phenylephrine bolus. PbtO2 was 22 (median; 5%-95% range, 4.6-54) mmHg during 30% oxygen, 68 (8.4-99) mmHg during 80% oxygen (p = .004 compared to 30% oxygen), 21 (4.5-81) mmHg before phenylephrine, and 19 (4.2-56) mmHg after phenylephrine (p = .56 compared to before phenylephrine).

Conclusion: In patients undergoing craniotomy under general anaesthesia, brain tissue oxygen tension increased with a high inspiratory oxygen fraction but remained unchanged after a bolus dose of phenylephrine.

Keywords: cerebral oxygenation; hyperoxia; neurosurgery; oxygen; phenylephrine.

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Conflict of interest statement

Sofie S. Pedersen: Reports indirect research funding from Boehringer Ingelheim outside the submitted work. Christian S. Meyhoff: Co‐founder of a start‐up company, WARD247 ApS, with the aim of pursuing the regulatory and commercial activities of the WARD‐project (wireless assessment of vital signs). WARD247 ApS has finalised terms for licence agreement for any WARD‐project software and patents. One patent has been filed: ‘Wireless Assessment of Respiratory and circulatory Distress (WARD)—Clinical Support System (CSS)—an automated clinical support system to improve patient safety and outcomes’. Christian S. Meyhoff also reports direct and indirect research funding from Merck Sharp & Dohme Corp., Radiometer and Boehringer Ingelheim, as well as lecture fees from Radiometer, all outside the submitted work. Markus Harboe Olsen: Unrestricted grant from Neurescue Aps outside the submitted work. Zara R. Stisen: None to be reported. Anton Lund: None to be reported. Kirsten Møller: None to be reported. Jane Skjøth‐Rasmussen: None to be reported. Finn B. Moltke: None to be reported. Martin Kryspin Sørensen: None to be reported.

Figures

FIGURE 1
FIGURE 1
Study flow chart
FIGURE 2
FIGURE 2
PbtO2 and ScO2 during FiO2 0.30 versus 0.80 and before versus after phenylephrine. Line plots of (A) PbtO2 (mmHg) before (n = 6) versus after (n = 6) phenylephrine and during FiO2 0.30 (n = 12) versus 0.80 (n = 11). (B) ScO2 (%) before (n = 10) versus after (n = 9) phenylephrine and during FiO2 0.30 versus 0.80 (n = 15)
FIGURE 3
FIGURE 3
Median PbtO2 1 min before and 1–5 min after phenylephrine intervention. Median PbtO2 (mmHg) (IQR) 1 min before (depicted by −1 min) and 1–5 min after phenylephrine intervention administered (at 0 min)
FIGURE 4
FIGURE 4
Median ScO2 1 min before and 1–5 min after phenylephrine intervention. Median ScO2(%) (IQR) 1 min before (depicted by −1 min) and 1–5 min after phenylephrine intervention administered (at 0 min)
See this image and copyright information in PMC

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