Exploration of the relationship between partial pressure of brain tissue oxygen and intracranial pressure

• Published in: Brain & spine 2024-01, Vol.4, p.102848, Article 102848
• Main Authors: Shaw, Martin, Moss, Laura, Piper, Ian, Kommer, Maya, Boulton, Richard, O'Kane, Roddy, Hawthorne, Christopher
• Format: Article
• Language: English
• Subjects: Intracranial pressure; Non-linear model; Partial pressure of brain tissue oxygen; Short Communication
• ISSN: 2772-5294; 2772-5294
• DOI: 10.1016/j.bas.2024.102848

Partial pressure of brain tissue oxygen (PbtO2) has been shown to be a safe an effective monitoring modality to compliment intracranial pressure (ICP) monitoring. It is related to metabolic activity, disease severity and mortality. Understanding the complex relationship between PbtO2 and ICP for patients with traumatic brain injury will enable better clinical decision making beyond simple threshold treatment strategies. Patients with PbtO2 monitoring were identified from the BrainIT database, a multi-centre dataset, containing minute by minute PbtO2 and ICP readings. Missing data was imputed and a multi-level log-normal regression model with a compound symmetry correlation structure was built. This accounted for any increased correlation due to the repeated measurements. The model was adjusted for mean arterial pressure and the partial pressure of carbon dioxide. Non-linearity was assessed using analysis of deviance and trends using expected marginal means. 11 subjects with over 82,000 readings were included. They had a median age of 38 (IQR: 37–47), 73% were male, a median length of stay of 11.8 (IQR: 6.6–19.7) days and a median extended Glasgow outcome scale of 7.00 (IQR: 5–8). There is a statistically significant (p