The introduction of brain tissue oxygen (PbtO₂) monitoring into the neuro-intensive care unit (NICU) has created exciting opportunities for intervention but requires many questions to be answered before it can achieve widespread adoption. This article will cover the technical aspects of PbtO₂ monitoring, the physiological correlates of PbtO₂, the published literature on PbtO₂ monitoring in children, and practical approaches to monitoring and managing PbtO₂ in the clinical situation.

PbtO₂ is measured and monitored continuously using a thin catheter inserted into brain parenchyma. It is increasingly being used in the management of patients with acute neurological pathology, most commonly severe traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH), to complement other forms of monitoring. The ease of use and the potential for continuously monitoring the adequacy of brain oxygenation and measuring its response to intervention in realtime have contributed to its growing popularity in the NICU, as clinicians try to avoid or ameliorate secondary injury to maximize the chance of a favorable outcome.

Post mortem¹ and clinical studies^2–4 suggest that secondary brain hypoxia–ischemia contributes significantly to poor outcome after TBI; therefore, the rationale for monitoring appears to be strong. The purposes of monitoring oxygenation of the brain are four-fold: to detect episodes of threatened brain ischemia/hypoxia early and respond immediately; to detect the adverse effects of therapy directed at other physiological parameters (e.g. hyperventilation for increased intracranial pressure [ICP]); to titrate therapy (e.g. optimizing cerebral perfusion pressure); and to assist interpretation of perturbations of other modalities, such as ICP. However, it is only recently that methods that enable monitoring of some aspects of brain oxygenation have begun to be used regularly in the NICU, of which PbtO₂ arguably appears to be the most promising.

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