Crystallization of LA and Adjuvant Mixtures in Cerebrospinal Fluid

Conditions

Hydrocephalus

Keywords

local anesthetics;, local anesthetic mixtures, cerebrospinal fluid, in vitro, crystallization, pH, adjuvants

Brief summary

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.

Detailed 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. 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.

Related papers

No related papers found yet.

Interventions

None listed

Study design

Observational model

OTHER

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

No

Inclusion criteria

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

Exclusion criteria

* Age \< 18 years

Design outcomes

Primary

Measure	Time frame	Description
Grade of Crystallisation	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

Measure	Time frame	Description
pH value and of CSF and CSF LA mixtures	1 hour	pH value
pCO2 of CSF and CSF LA mixtures	1 hour	pCO2 in mmHg

Countries

Austria

Contacts

PRINCIPAL_INVESTIGATORElisabeth Gasteiger, MD PhD

Medical Unicersity Innsbruck

Outcome results