Blood pressure and cerebrospinal fluid pressure studies during lumbar air encephalography.

Blood pressure and cerebrospinal fluid pressure changes were studied during lumbar air encephalography under general anaesthesia. Two anaesthetic techniques were used. In one group spontaneous respiration with nitrous oxide, oxygen and halothane was used and in the other controlled ventilation with nitrous oxide and oxygen was maintained. Larger falls in blood pressure, on sitting up, were seen in the spontaneous respiration group and cerebrospinal fluid pressures were also higher in these patients but never rose to dangerous levels. It is concluded that a technique of controlled ventilation with nitrous oxide and oxygen is preferable during lumbar air encephalography.