Factors affecting Cerebrospinal Fluid Flow in a Shunt System

Nineteen adult hydrocephalic patients under treatment with a medium-pressure Raimondi′s peritoneal catheter were studied for various factors believed to affect the cerebrospinal fluid (CSF) flow rate through the shunt system. Observation of body position in three patients revealed that the recumbent position mean flow rate was less than 0.01ml/min and that head elevation led to increases in the flow rate, of 0.04 to 0.08ml/min at an inclination of 30°, and of 0.14 to 0.43ml/min at 80° In most patients, coughing led to a sudden increase in flow rate, with a rapid elevation of intracranial pressure (ICP). Continuous electroencephalographic, electro-oculographic, electromyographic, respiratory, and ICP monitoring disclosed a slight increase in ICP during the rapid eye movement (REM) sleep in three of four patients studied. The CSF flow rate was highest between 10 pm and 7 am, and this nocturnal increase was considered to be related to the elevation of ICP during REM sleep. There did not appear to be any relationship between the rate of CSF flow and the volume of fluid intake. In two patients given rapid intravenous administration of 50g of glycerol or 500 to 1, 000ml of lactated Ringer′s solution there were no significant changes in CSF flow. In conclusion, increases in the flow rate of CSF through a shunt system were related to body position, coughing, and increases in ICP during the REM sleep.