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NCT Number: NCT07442929

Crystallization of LA and Adjuvant Mixtures in Cerebrospinal Fluid

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.

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Key information

Conditions

Hydrocephalus Brain Diseases Central Nervous System Diseases Nervous System Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Medical University Innsbruck

Innsbruck, Tyrol, 6020, Austria

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients with normal pressure hydrocephalus scheduled for elective lumbar puncture.

Exclusion criteria

  • Age < 18 years

Treatment and study plan

Primary outcomes

  1. Grade of Crystallisation

    Time frame: 1 hour

    For the grading of detectable precipitations, a scale from 0 (no signs of precipitation / single particulates < 10 μm) to 5 (heavy polymorphic crystallization: > 100 solid bodies > 10 μm, and > 1 solid body > 50 μm or > 1 solid body > 100 μm) will be used.

Secondary outcomes

  1. pH value and of CSF and CSF LA mixtures

    Time frame: 1 hour

    pH value

  2. pCO2 of CSF and CSF LA mixtures

    Time frame: 1 hour

    pCO2 in mmHg

Sponsors and collaborators

Lead sponsor

Medical University Innsbruck

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Mar 2, 2026
Registry last updated
Aug 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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