Crystallization of LA and Adjuvant Mixtures in Cerebrospinal Fluid

Trial details

Who runs it

Medical University Innsbruck

Trial code

NCT07442929

Record updated

25 August 2026

Original description

Different mixtures of local anesthetics or local anesthetics with adjuvants that are known to precipitate in vitro are tested in human cerebrospinal fluid (CSF). CSF is gained from patients with normal pressure hydrocephalus scheduled for elective lumbar puncture. Patients signed an ICF for leftover samples.Read full original descriptionShow less

Crystallization of Local Anesthetic and Adjuvant Mixtures in Cerebrospinal Fluid as a Model for Interstitial Space - a Semiquantitative in Vitro Trial

Different mixtures of local anesthetics or local anesthetics with adjuvants that are known to precipitate in vitro are tested in human cerebrospinal fluid (CSF). CSF is gained from patients with normal pressure hydrocephalus scheduled for elective lumbar puncture. Patients signed an ICF for leftover samples.

CSF will be assessed for pH values at different timepoints (t0-t3; 0 to 60 minutes).

In a second step six commonly used mixtures of LA with LA or LAs with adjuvants will be mixed using the following mixture ratios: ropivacaine 0.75% + lidocaine 2% (ratio 1:1), ropivacaine 0,75% + mepivacaine 2% (ratio 1:1), ropivacaine 0.75% + chloroprocaine 2% (ratio 1:1), lidocaine 2% + sodium bicarbonate 8.4% (ratio 1:0.1), ropivacaine 0.75% + lidocaine 2% + sodium bicarbonate 8.4% (ratio 1:1:0.1) and ropivacaine 0.75% + dexamethasone (1.5:1). The used mixture ratios are inspired by commonly mixtures described in the current literature and have been proven to precipitate in vitro. For every mixture, a Grade of Crystallisation will be determined at baseline without CSF and then at t0 (immediately) to t3 (60 minutes) every 15 minutes.

Inclusion: Patients with normal pressure hydrocephalus scheduled for elective lumbar puncture.

Exclusion: Age < 18 years.

ClinicalTrials.gov NCT07442929