[Effect of general anesthesia induction on cerebral circulation in subacute and chronic subdural hematoma assesssed...

Cerebral circulation in 21 patients with subacute (SSH) and chronic subdural hematoma (CSH) were studied by computerized rheoencephalography before and after induction of general anesthesia. ECG and REG courses were sampled with a frequency of 62.5 Hz during a period of 15 minutes, and both sets of data points were fitted by an cubic polynomials. We introduced the classification of the REG pulse related waveform (PRW) according to the number of the inflection points in the anacrotic branch. The cases of normal pulse form, with almost vertical systolic upstroke corresponded with only one inflection point in the ascending branch (grade I). We assumed that the presence of three or greater number of inflection points reflected more gradual systolic rise, is characteristic for regressive changes of the arterial wall (grade II). The relative duration of the anacrotic branch was calculated. The first obtained result was the significant correlation between REG and clinical status. The unfavorable effect of induction on cerebral circulation corresponded with less favorable results of treatment. Our preliminary results indicate the clinical value of REG examination in the preoperative evaluation of the cerebral circulation.