does flexed/extended positioning matter for LP opening pressure?

24 Jan

BOTTOM LINE (at the top): not really. not much.

STUDY 1: (Avery et al.)

53 children had their opening pressure measured in both the flexed and extended lateral recumbent positions (mean age = 11.7 years)

mean opening pressure was higher in the flexed (25.1 +/- 9.2 cm H2O) compared with the extended (24.4 +/- 8.4 cm H2O) position

Most (92.4%) opening pressure measurements had less than a 5 cm H2O difference between positions.

a statistically significant decrease in cerebrospinal fluid opening pressure, although the magnitude of the difference is small and of doubtful clinical significance


STUDY 2: (Sithinamsuwan P et al.)

(n = 83) underwent lumbar puncture while in the flexed lateral decubitus position and then were moved to the relaxed position.

Mean pressures for Flexed and recubment position were 178.54 and 160.52 mmH2O respectively, p <0.001.

authors recommend an equation…or using 200 mmH2O as the threshold for increased ICP with flexed posture.

if 20mmH2O is your upper limit threshold for opening pressure, the difference doesn’t matter much.



References: study 1, study 2, picture


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