THE EFFECT OF REVERSAL OF MYONEURAL BLOCKADE ON CEREBROSPINAL-FLUID PRESSURE FOLLOWING CEREBRAL ANEURYSM SURGERY

Drugs with a depolarizing action at the myoneural junction may cause a rise in intracranial pressure. Neostigmine, which is commonly used to reverse residual myoneural blockade, has a depolarizing action, and y et its effect on intracranial pressure is unknown. Lumbar cerebrospina l fluid pressure, which mirrors intracranial pressure, was determined in 12 patients undergoing cerebral aneurysm surgery. Cerebrospinal flu id pressure was measured during dense myoneural blockade and after its reversal with neostigmine. These effects on cerebrospinal fluid press ure were compared with those produced when the arterial partial pressu re of carbon dioxide (Paco(2)) rose from 4 to 5 kPa. After reversal of myoneural block, there was a small (nonsignificant) change in cerebro spinal fluid pressure from 3.6 to 4.3 kPa and a larger (significant) r ise in cerebrospinal fluid pressure to 9.7 kPa when the Paco(2) was al lowed to rise. In this group of patients, reversal of myoneural blocka de with neostigmine causes no significant change in cerebrospinal flui d pressure.