The Importance of PbtO2Probe Location for Data Interpretation in Patients with Intracerebral Hemorrhage

Background/objective Monitoring of brain tissue oxygen tension (PbtO2) provides insight into brain pathophysiology after intracerebral hemorrhage (ICH). Integration of probe location is recommended to optimize data interpretation. So far, little is known about the importance of P(bt)O(2)catheter location in ICH patients. Methods We prospectively included 40 ICH patients after hematoma evacuation (HE) who required PbtO2-monitoring. PbtO2-probe location was evaluated in all head computed tomography (CT) scans within the first 6 days after HE and defined as location in thehealthy brain tissueorperilesionalwhen the catheter tip was located within 1 cm of a focal lesion (hypodense or hyperdense). Generalized estimating equations were used to investigate levels of P(bt)O(2)in relation to different probe locations. Results Patients were 60 [51-66] years old and had a median ICH-volume of 47 [29-60] mL. Neuromonitoring probes remained for a median of 6 [2-11] days. PbtO2-probes were located in healthy brain tissue in 18/40 (45%) patients and in perilesional brain tissue in 22/40 (55%) patients. In the acute phase after HE (0-72 h), P(bt)O(2)levels were significantly lower (21 +/- 12 mmHg vs. 29 +/- 10 mmHg,p = 0.010) and brain tissue hypoxia (BTH) was more common in the perilesional area as compared to healthy brain tissue (46% vs. 19%, adjOR 4.0, 95% CI 1.54-10.58,p = 0.005). Episodes of BTH significantly decreased over time in patients with probes in perilesional location (p = 0.001) but remained stable in normal appearing area (p = 0.485). A significant association between BTH and poor functional outcome was only found when probes were located in the perilesional brain tissue (adjOR 6.6, 95% CI 1.3-33.8,p = 0.023). Conclusions In the acute phase, BTH was more common in the perilesional area compared to healthy brain tissue. The improvement of BTH in the perilesional area over time may be the result of targeted treatment interventions and tissue regeneration. Due to the localized measurement of invasive neuromonitoring devices, integration of probe location in the clinical management of ICH patients and in research protocols seems mandatory.

Automated summary

The location of PbtO2 probes in ICH patients significantly affects brain tissue oxygen tension levels and pathophysiological status. Brain tissue hypoxia is more common in perilesional area, and targeted treatment interventions in this area may help improve the condition.