Assessment of intracranial pressure volume relationships in childhood: thelumbar infusion test versus intracranial pressure monitoring

Object: This study was undertaken to compare the results of two tests that are widely used to assess intracranial pressure-volume relationships in chi ldren: the lumbar steady state infusion test providing information about th e resistance to cerebrospinal fluid (CSF) outflow (R-out). and continuous i ntracranial pressure (ICP) monitoring. Methods: The study included 28 child ren aged 5-91 months, on whom both tests were performed. The median duratio n between the tests was 1 month. With the child in general narcosis, the lu mbar CSF pressure was recorded before and during infusion of artificial CSF and the R-out was calculated on the basis of the opening (Po) and plateau (Pp) pressures (R-out = Pp-Po/infusion rate). ICP was recorded every 5 s us ing a computer-based system. Conclusions: We found no significant correlati on between R-out and mean ICP asleep. There were no significant relationshi ps between abnormal mean ICPs during sleep (defined as either 10 or 15 mmHg ) and abnormally high R-out values (defined as either 10 or 12 mmHg/ml/min) , and no significant relationships between abnormally high R-out values (10 or 12 mmHg ml(-1) min(-1)) and the presence of abnormal ICP elevations (de fined as either 20 or 25 mmHg and lasting 5 min). Therefore the calculation of R-out by the infusion test performed on children under general anesthes ia gave no reliable prediction of abnormal ICP.