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

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 O(2), CO(2), pH, HCO(3)- 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 (PtiO(2)) 21.0 mmHg, standard deviation +/- 7.9; PtiCO(2) 60.2 +/- 17.2 mmHg; temperature 36.9 +/- 0.4 degrees C, pH 7.08 + 0.2; and HCO3 17.1 +/- 3.7. Mean peritumoural brain values in 5 patients were PtiO(2) 29.1 +/- 27.6 mmHg; PtiCO(2) 48.6 +/- 7.0 mmg; temperature 36.4 +/- 0.6 degrees C; pH 7.20 +/- 0.09 and HCO3 19.1 +/- 3.5. There were trends for the PtiO(2) to decrease with increasing brain depth. As glioblastoma PtiCO(2) levels decreased, pH increased. There were no relationships between either tumoural PtiO(2) and pH, or PtiO(2) and PtiCO(2), 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 PtiO(2).



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.