Noninvasive Technique for Evaluation of Cerebral Edema in Patients with Brain Injury

Abstract

Objective: to monitor the efficiency of intensive therapy for brain injury, which presents a great difficulty due to the fact that available noninvasive monitoring techniques for intracranial processes are unavailable. The present study was undertaken to substantiate the monitoring of cerebral hydration by a noninvasive bioimpedance technique.Subjects and methods. Twenty-eight patients with isolated brain injury (BI) and edema verified by computed tomography were examined. A control group consisted of 70 persons without signs of mental confusion and BI in the history. The noninvasive bioimpedance technique was used to evaluate the degree of brain tissue hydration. The hydration coefficient was developed in healthy persons, which reflected the degree of interstitial space hydration in the examined patients with BI. In parallel, cerebral hemodynamic parameters were recorded by rheoencephalography. Cerebral oxygen budget was estimated by jugular oximetry. For correction of cerebral edema, all the patients underwent hyper-ventilation in restored systemic blood circulation and provided pulmonary gas exchange. The study was conducted at 2 stages: before and after 30-minute moderate hyperventilation.Results. According to the effect of hyperventilation, the patients were divided into two groups: 1) 17 patients in whom hyperventilation was attended by the decrease in cerebral liquid volume; 2) 11 patients in whom hyperventilation was accompanied by the accumulation of cerebral interstitial liquid.Conclusion. A noninvasive brain impedance technique may be used as monitoring to evaluate the efficiency of antiedematous therapy for brain injury.

Keywords

• brain edema
• noninvasive impedance technique
• hyperventilation
• cerebral blood flow