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

What this Trial Is About

This research investigates how different mixtures of local anesthetics and their combinations with other drugs behave when mixed with human cerebrospinal fluid CSF. The study focuses on patients with normal pressure hydrocephalus who are scheduled for an elective lumbar puncture. The main goal is to analyze how these drug mixtures crystallize over time, which is important for understanding their behavior in the body. The study evaluates six specific mixtures of local anesthetics and adjuvants, including combinations like ropivacaine with lidocaine, mepivacaine, chloroprocaine, sodium bicarbonate, and dexamethasone in various ratios. These mixtures are tested in vitro by mixing with CSF collected from patients. Researchers measure the grade of crystallization at the start and at multiple intervals up to 60 minutes, as well as pH and pCO2 values of the mixtures. Participants provide leftover CSF samples obtained during their scheduled lumbar puncture. The samples are assessed at baseline and every 15 minutes for one hour to track crystallization and chemical changes. The primary outcome is the grade of crystallization within this hour. Secondary outcomes include pH and pCO2 levels of the CSF and mixtures. The study spans from September 2025 to September 2026 under the Medical University Innsbruck.

Crystallization of LA and Adjuvant Mixtures in Cerebrospinal Fluid