Relationship Between Brain Tissue Oxygen and Near-Infrared Spectroscopy in Patients with Nontraumatic Subarachnoid Hemorrhage: Invited Commentary

Excerpt

In this new study developed by the Hugues de Courson team at Bordeaux University Hospital [1], the interchangeability between brain tissue oxygen (PbtO₂) and near-infrared spectroscopy (NIRS) in patients suffering from nontraumatic subarachnoid hemorrhage (SAH) was evaluated for the assessment of cerebral oxygenation. The authors designed this study, despite knowing all the limitations of NIRS. However, they considered it essential to do so, as PbtO₂ is an invasive monitoring system (involves the intracranial insertion of a catheter) and is not available worldwide. Unfortunately, their data show no significant correlation between NIRS and PbtO₂ values in patients with SAH. NIRS is unable to detect PbtO₂ values below 20 mm Hg and decreases in PbtO₂ values greater than or equal to 10%. De Courson et al. [1] conclude that the use of PbtO₂ cannot be substituted for NIRS in patients with SAH. Although this study does not have a real sample size, it was performed with a very well-done statistical analysis. On the other hand, however, as specified in the limitations, the data were collected manually by the assistance staff on an hourly basis: apparently, this reduces the ability to detect minimal variations in values over time. …