Background/Objectives The prevalence of brain tissue hypoxia (BTH; PbtO2 < 20 mm Hg) in patients with spontaneous ICH is not well established. In this study, we aimed to quantify the prevalence of BTH and to assess determinants of brain tissue normoxia (BTN; PbtO2 ≥ 20 mm Hg) and BTH resolution. Methods This retrospective cohort study included 58 patients with ICH admitted to a neurological intensive care unit (ICU) between 2010 and 2020 with multimodal invasive neuromonitoring. BTN was sought by avoiding low cerebral perfusion pressure (CPP) and low blood hemoglobin levels, and by maintaining normocapnia, normoxemia, normothermia, and metabolic homeostasis. Hourly PbtO2, CPP, and temperature data were matched with intermittent variables (blood gases, hemoglobin, glucose, sodium, and microdialysis) over 10 days. Regression analyses were performed using generalized estimating equations to account for repeated measurements. Results Patients were 61 [interquartile range (IQR), 55–69] years old and presented with an ICH score of 2 (1–3). Of the patients, 52 (90%) underwent surgical evacuation via hemicraniectomy and/or craniotomy, while 6 (10%) received invasive neuromonitoring only. The median initial ICH volume was 40.2 (IQR 29.5–55.8) mL. Surgical evacuation achieved a median reduction of 86.6% (IQR 69.0–94.2), leaving a median residual volume of 5.5 (IQR 3.0–14.1) mL. The overall prevalence of BTH was 31%. In multivariable analysis, the following factors led to the highest percentage of BTN: CPP 80–89 mm Hg [odds ratio (OR) 1.88, 95% confidence interval (CI) 1.32–2.68, p < 0.001; reference: < 60 mm Hg], partial pressure of oxygen (PaO2) 90–99 mm Hg (OR 1.64, 95% CI 1.15–2.14, p = 0.001; reference: < 80 mm Hg), core body temperature 36.0–37.4 °C (OR 2.10, 95% CI 1.34–3.28, p = 0.001; reference: < 36.0 °C), PaO2/fraction of inspired oxygen (FIO2) 100–199 (OR 3.52, 95% CI 1.60–7.75, p = 0.002; reference: < 100) in a model corrected for probe position. Only CPP [74.6 (66.8–82.7) vs. 72.5 (64.9–80.2) mm Hg, p < 0.001)] was significantly higher after BTH resolution as compared with the time when PbtO2 was lowest during 229 BTH episodes. Conclusions BTH was observed during 31% of the monitored time in patients with a large hematoma volume despite the use of a PbtO2-targeted therapy. These findings generate the hypothesis that physiological determinants, such as CPP, are significantly associated with the achievement of BTN in regions near to the ICH.

Determinants of Brain Tissue Normoxia in Patients with Large Spontaneous Intracerebral Hemorrhage

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2026年6月23日

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Anna Berek,
Philipp Kindl,
Bogdan Ianosi,
Max Gaasch,
Mario Kofler,
Melanie Bergmann,
Lauma Putnina,
Raimund Helbok,
Alois J. Schiefecker,
Bettina Pfausler,
Ronny Beer,
Verena Rass

摘要

Background/Objectives

The prevalence of brain tissue hypoxia (BTH; P_btO₂ < 20 mm Hg) in patients with spontaneous ICH is not well established. In this study, we aimed to quantify the prevalence of BTH and to assess determinants of brain tissue normoxia (BTN; P_btO₂ ≥ 20 mm Hg) and BTH resolution.

Methods

This retrospective cohort study included 58 patients with ICH admitted to a neurological intensive care unit (ICU) between 2010 and 2020 with multimodal invasive neuromonitoring. BTN was sought by avoiding low cerebral perfusion pressure (CPP) and low blood hemoglobin levels, and by maintaining normocapnia, normoxemia, normothermia, and metabolic homeostasis. Hourly P_btO₂, CPP, and temperature data were matched with intermittent variables (blood gases, hemoglobin, glucose, sodium, and microdialysis) over 10 days. Regression analyses were performed using generalized estimating equations to account for repeated measurements.

Results

Patients were 61 [interquartile range (IQR), 55–69] years old and presented with an ICH score of 2 (1–3). Of the patients, 52 (90%) underwent surgical evacuation via hemicraniectomy and/or craniotomy, while 6 (10%) received invasive neuromonitoring only. The median initial ICH volume was 40.2 (IQR 29.5–55.8) mL. Surgical evacuation achieved a median reduction of 86.6% (IQR 69.0–94.2), leaving a median residual volume of 5.5 (IQR 3.0–14.1) mL. The overall prevalence of BTH was 31%. In multivariable analysis, the following factors led to the highest percentage of BTN: CPP 80–89 mm Hg [odds ratio (OR) 1.88, 95% confidence interval (CI) 1.32–2.68, p < 0.001; reference: < 60 mm Hg], partial pressure of oxygen (P_aO₂) 90–99 mm Hg (OR 1.64, 95% CI 1.15–2.14, p = 0.001; reference: < 80 mm Hg), core body temperature 36.0–37.4 °C (OR 2.10, 95% CI 1.34–3.28, p = 0.001; reference: < 36.0 °C), P_aO₂/fraction of inspired oxygen (F_IO₂) 100–199 (OR 3.52, 95% CI 1.60–7.75, p = 0.002; reference: < 100) in a model corrected for probe position. Only CPP [74.6 (66.8–82.7) vs. 72.5 (64.9–80.2) mm Hg, p < 0.001)] was significantly higher after BTH resolution as compared with the time when P_btO₂ was lowest during 229 BTH episodes.

Conclusions

BTH was observed during 31% of the monitored time in patients with a large hematoma volume despite the use of a P_btO₂-targeted therapy. These findings generate the hypothesis that physiological determinants, such as CPP, are significantly associated with the achievement of BTN in regions near to the ICH.