[Cerebral blood flow and CO2-responsiveness in early aneurysmal surgery].

The purpose of our study was to investigate the fact that, during aneurysmal surgery, the degree of reduced cerebral blood flow (CBF) and disturbed CO2 responsiveness due to subarachnoid hemorrhage (SAH) were influenced by the elapse of time from SAH to surgery. Fifteen patients with SAH, between 26 and 63 years of age (44 +/- 16) were in grade-I according to the Hunt & Hess scale. These patients were divided into three groups according to the time lapse from onset of SAH to aneurysmal surgery. In group A (G-A: n = 4) the operations were performed within 12 hours from the onset of SAH. In group B (G-B: n = 4) the operations were performed between 12 and 24 hours after SAH, and in group C (G-C: n = 7) between 24 and 72 hours after the onset of SAH. All these operations were done under general anesthesia with N2O 4 l/min, O2 3 l/min and halothane 0.3-0.8%, and ventilation was controlled with pancuronium bromide. After about three hours from induction of anesthesia, but restricted within microsurgical maneuver, our study was performed. CBF and CO2 responsiveness were estimated with the cerebral circulatory index (inverse of arterial oxygen content minus jugular venous oxygen content: CCI). The O2 content and CCI were calculated with the following formula: Cont. O2 = 1.39 X Hb (g/dl) X O2 Sat + 0.003 X PO2, CCI = 1/CaO2-CjO2 where CaO2 is the content of O2- in arterial blood and CjO2 in jugular blood. To estimate the cerebral CO2 responsiveness, we changed the tidal volume during the period studied.(ABSTRACT TRUNCATED AT 250 WORDS)