Reference values for intracranial pressure and lumbar cerebrospinal fluid pressure: a systematic review

Abstract

Background: Although widely used in the evaluation of the diseased, normal intracranial pressure and lumbar cerebrospinal fluid pressure remain sparsely documented. Intracranial pressure is different from lumbar cerebrospinal fluid pressure. In addition, intracranial pressure differs considerably according to the body position of the patient. Despite this, the current reference values do not distinguish between intracranial and lumbar cerebrospinal fluid pressures, and body position-dependent reference values do not exist. In this study, we aim to establish these reference values.

Method: A systematic search was conducted in MEDLINE, EMBASE, CENTRAL, and Web of Sciences. Methodological quality was assessed using an amended version of the Joanna Briggs Quality Appraisal Checklist. Intracranial pressure and lumbar cerebrospinal fluid pressure were independently evaluated and subdivided into body positions. Quantitative data were presented with mean ± SD, and 90% reference intervals.

Results: Thirty-six studies were included. Nine studies reported values for intracranial pressure, while 27 reported values for the lumbar cerebrospinal fluid pressure. Reference values for intracranial pressure were - 5.9 to 8.3 mmHg in the upright position and 0.9 to 16.3 mmHg in the supine position. Reference values for lumbar cerebrospinal fluid pressure were 7.2 to 16.8 mmHg and 5.7 to 15.5 mmHg in the lateral recumbent position and supine position, respectively.

Conclusions: This systematic review is the first to provide position-dependent reference values for intracranial pressure and lumbar cerebrospinal fluid pressure. Clinically applicable reference values for normal lumbar cerebrospinal fluid pressure were established, and are in accordance with previously used reference values. For intracranial pressure, this study strongly emphasizes the scarcity of normal pressure measures, and highlights the need for further research on the matter.

Keywords: CSF; Cerebrospinal fluid pressure; ICP; Intracranial pressure; Reference intervals; Reference values.

Fig. 1

Flowchart of study selection process. The section “insufficient data” covers studies did not report sufficient statistical data to be included in statistical analysis. Thus, no standard deviations, confidence intervals or reference intervals were reported in these studies. The included articles “Other sources” were found by manual searching the reference list of included studies

Fig. 2

Forest plot of lumbar cerebrospinal fluid pressure and intracranial pressure. Two forest plots describing the weighted average of lumbar cerebrospinal fluid pressure (LCSF_op) and intracranial pressure (ICP) reported in each included study. The LCSF_op is presented to the left and grouped into different body positions: lateral recumbent position and supine position. ICP is presented to the right, and also sub-grouped into different body positions: daytime, nighttime, supine and upright position