A comparison of simple tests to distinguish cerebrospinal fluid from saline

Abstract

Purpose: This prospective study was undertaken to determine if anesthesiologists of different levels of training, using simple tests, can distinguish cerebrospinal fluid (CSF) from saline.Methods: Thirty-two anaesthetists, divided into four groups, dependent upon levels of training, participated in the study. Each was asked to distinguish saline from an artificial CSF solution using four different tests: tactile temperature, glucose strip, pH strip, and turbidity when mixed with thiopental.Results: Participants identified cerebrospinal fluid correctly with 8496 accuracy using the temperature test, 9796 using the glucose test, 91% using the pH test, and 5096 using the thiopentone test, More than half of the participants guessed while using the thiopentone test, and those who did not guess were only 4796 accurate, Conclusion: Level of training made no difference in distinguishing CSF from saline. No one test was 10096 reliable, Clinical utility of the thiopentone test appears to be limited. The temperature, glucose, and pH tests, when used together, appear to be a useful way of distinguishing CSF from saline.Objectif : Cette Etude prospective visait ~ determiner si des anesth6sistes possEdant des degrEs diff&ents de formation pouvaient, fi l'aide de simples tests, faire la distinction entre du liquide c6phalo-rachidien (LCR) et du sol.phys (SP).M&hod~ : Trente-deux anesthEsistes, divis& en quatre groupes d'aprEs leur niveau de formation, ont particip~ I'&ude. On a demand6 a chacun de faire la distinction entre du SP et une solution artificielle de LCR en utilisant quatre tests dif&ents : la temp@rature tactile, le papier r@actif au glucose, le papier r~actif au pH et 1'6preuve de turbidit6 au thiopentone. ][~ultats : les participants ont identifi6 correctement le LCR avec un degrE d'exactitude de 8496 avec le test de la teml~rature, 9796 avec le test du glucose, 91% avec le test du pH et 5096 avec le test de turbidit6 au thiopentone. Plus de la moiti6 des participants ont ~devin6~ avec le test au thiopentone et rexactitude n'Etait que de 4796 chez ceux qui n'avaient pas devinE.Conclusion : Le niveau de formation n'a fait aucune difference Iorsqu'il s'agissait de distinguer entre le LCR et le solut6 physiologique. Aucun des tests n'Etait fiable ~ 10096. Les tests de la teml~rature, du glucose et du pH, utJlisEs conjointement, semblent utiles pour distinguer le liquide cEphalo-rachidien du solute physiologique.

A comparison of epidural and cerebrospinal fluid glucose in parturients at term: an observational study

“…The volume of saline collected was not standardized, and this may be considered a study limitation since the volume injected may influence the volume leaking out. However, our observational study, unlike previous studies, 11,12 was designed to reflect clinical practice and therefore optimise external validity. The two dural punctures that occurred in the study were clinically obvious.…”

“…Previous studies have used qualitative and semi-quantitative methods, including pH and glucose measurements using urinary dipstick reagent strips. [10][11][12] Dural punctures generally occur during insertion of the epidural needle, 13 and therefore a bedside glucometer was used to measure glucose content at that time.…”

“…Several techniques to distinguish between CSF and saline have been proposed, including testing for the presence of protein or glucose, temperature, pH and changes in turbidity when mixed with thiopental. [10][11][12] No single test is reliable and all are qualitative tests that generally use CSF substitutes rather than real CSF. 11,12 No quantitative tests to distinguish between CSF and saline during epidural catheter insertion have been described.…”

“…[10][11][12] No single test is reliable and all are qualitative tests that generally use CSF substitutes rather than real CSF. 11,12 No quantitative tests to distinguish between CSF and saline during epidural catheter insertion have been described. Although bedside testing for glucose may be diagnostic for CSF, this has not been formally tested.…”

Neuraxial Blocks: Spinal and Epidural Anesthesia

“…A higher viscosity, higher temperature ( Fig. 41.39 ), near-neutral pH, higher glucose content, and turbidity with thiopentone help identify the fl uid as CSF [ 73 ]. If the fl uid is not CSF, one can proceed with the procedure.…”