Assessment of physiological parameters within glioblastomas in awake patients: a prospective clinical study

Abstract

Object. Multiparametric brain monitoring probes now make it possible to measure cerebral physiology. This prospective clinical study was designed to evaluate the pathophysiological environment of tumoural and peritumoural tissue O₂, CO₂, pH, HCO₃- and temperature of awake patients with glioblastoma.

Methods. A Neurotrend multiparametric sensor was placed using intraoperative image guidance into glioblastoma after biopsy under general anesthetic. Postoperative monitoring was then performed in awake patients.

Results. Twelve patients were recruited and monitoring was performed, and well tolerated in 9 for up to 22 hrs. Mean glioblastoma tumour values were: tissue oxygen pressure (PtiO₂) 21.0 mmHg, standard deviation ± 7.9; PtiCO₂ 60.2 ± 17.2 mmHg; temperature 36.9 ± 0.4°C, pH 7.08 + 0.2; and HCO₃ 17.1 ± 3.7. Mean peritumoural brain values in 5 patients were PtiO₂ 29.1 ± 27.6 mmHg; PtiCO₂ 48.6 ± 7.0 mmg; temperature 36.4 ± 0.6°C; pH 7.20 ± 0.09 and HCO₃ 19.1 ± 3.5. There were trends for the PtiO₂ to decrease with increasing brain depth. As glioblastoma PtiCO₂ levels decreased, pH increased. There were no relationships between either tumoural PtiO₂ and pH, or PtiO₂ and PtiCO₂, however there were large intra- and inter-tumoural variation in monitoring values. There were technical problems in some patients with the Neurotrend sensor that limited its application, and that compromised aspects of data collection and interpretation, particularly of PtiO₂.

Conclusion. This study has shown that this novel approach to monitoring glioma pathophysiology is feasible and well tolerated by patients. The data, much of which is novel, contributes to the knowledge of glioblastoma pathophysiology. However, further study and clinical exploitation awaits the development of a more reliable multiparametric sensor.

Key words:

• glioblastoma
• monitoring
• oxygen
• hypoxia pathophysiology

Acknowledgment

This work was funded by a research grant from the Melville Trust.

Declaration of interest: IRW received an Educational Travel Grant from Codman to attend a conference on Neuromonitoring in June 2005. IRW has also been paid consultancy and received ad hoc lecture fees from Link Pharmaceutical, Archimedes Pharmaceutical, Schering-Plough and Ark Therapeutics. No other authors have any conflict of interest. The authors alone are responsible for the content and writing of the paper.