Measurement of cerebrospinal fluid output through external ventricular drainage in one hundred infants and children: correlation with cerebrospinal fluid production.

OBJECTIVE Cerebrospinal fluid (CSF) production rates influence shunt design and the care of children with hydrocephalus. Measurement of hourly CSF output through external ventricular drainage (EVD) reflects the CSF production. In the present study, hourly CSF outputs in children with hydrocephalus were measured while they were treated with EVD and correlated with the age, sex and body weight of the patients as well as other clinical parameters. METHODS One hundred children with hydrocephalus due to various causes had EVD treatment. Twenty-six had EVD on two or three separate occasions; thus, the CSF output measurements were observed and analyzed on the basis of 130 EVDs. The most common reason for EVD treatment was shunt infection (n = 75). The duration of EVDs ranged from 25 to 774 h (mean 269 h). The height of the drip chamber from the mid-head position ranged from 0 to 23 cm (mean 9.8 cm). The hourly CSF output was analyzed according to the patient's age, sex and body weight as well as the presence of CSF infection. RESULTS The hourly CSF output rapidly increases during the first year of life. By the second year, it reaches 64% of the hourly CSF output of 15-year-old children. The mean hourly output ranged from 0.1 to 26.5 ml/h (mean 8.1 ml/h), with the standard deviation ranging from 0.4 to 10.8 ml/h (mean 5.2 ml/h). A regression analysis indicated that the age and body weight appeared to correlate with the hourly CSF output. Using the natural logarithm of age, body weight and sex, these predictors accounted for 50.9% of the variability in hourly CSF output. The regression equation is as follows: hourly CSF output = 2.78 - 2.23(male = 0, female = 1) + 0.97 log(age in years) + 2.26 log(body weight in kg). R sd = 3.36, R(2) = 0.509. The type of infecting organism and the height of EVD did not influence the overall CSF output. CONCLUSION The hourly CSF output fluctuates, but the CSF output increases logarithmically with age and body weight. The gender also influences the CSF output, with males having a greater output than females. The data produced by the present study will help us to understand CSF production rates in developing children. They will also help us in the care of children receiving EVD treatment, as well as in selecting and designing shunt systems.