gms | German Medical Science

64th Annual Meeting of the German Society of Neurosurgery (DGNC)

German Society of Neurosurgery (DGNC)

26 - 29 May 2013, Düsseldorf

Pharmacodynamics of S-Ketamine in gyrencephalic spreading depolarizations

Meeting Abstract

  • Edgar Santos - Neurochirurgische Klinik, Ruprecht-Karls-Universität Heidelberg
  • Renan Sanchez-Porras - Neurochirurgische Klinik, Ruprecht-Karls-Universität Heidelberg
  • Michael Schoell - Neurochirurgische Klinik, Ruprecht-Karls-Universität Heidelberg
  • Zelong Zheng - Neurochirurgische Klinik, Ruprecht-Karls-Universität Heidelberg
  • Andreas Unterberg - Neurochirurgische Klinik, Ruprecht-Karls-Universität Heidelberg
  • Oliver W. Sakowitz - Neurochirurgische Klinik, Ruprecht-Karls-Universität Heidelberg

Deutsche Gesellschaft für Neurochirurgie. 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC). Düsseldorf, 26.-29.05.2013. Düsseldorf: German Medical Science GMS Publishing House; 2013. DocMO.15.10

doi: 10.3205/13dgnc135, urn:nbn:de:0183-13dgnc1357

Published: May 21, 2013

© 2013 Santos et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Objective: Cortical spreading depolarizations are related to worse outcome in brain injury patients. Ketamine can reduce the incidence of CSDs in humans but the best administration regimen is yet unknown. The aim of this study was to characterize the effects of S-ketamine, using single i.v. bolus and continuous i.v. infusion, in the dynamics of blood volume changes using intrinsic optical signal imaging (IOS) during the induction, propagation and termination of CSDs in the porcine brain.

Method: Sixteen anaesthetized male German Landrace swine (mean weight of 30 kg) were craniotomized and monitored over 16 - 20 hours. Video recording was implemented using a camera with an optical bandpass filter (564 nm, FWHM: 15 nm) and a light source. Blood volume changes in relationship to a reference picture over the cortex surface were visualized over time. CSDs were induced by K+ stimulation in a selected gyrus in both hemispheres. A single dose of 125 mg S-ketamine bolus i.v. was given slowly to seven animals, continuous infusion of 120 mg/h for 2 hours was administered in six animals and an infusion of 60 mg/h for 2 hours was administered in three animals.

Results: Following a single bolus of S-ketamine there was a reduction of the spatial expansion of CSDs and a significant reduction in propagation velocity. Nevertheless, few CSDs still propagated in the vicinity of the stimulation but further expansion was blocked. The effect lasted for 30 - 40 minutes. Using continuous infusion at 60 mg/h also reduced spatial expansion. This was, however, less sharp delineated. An infusion at a rate of 120 mg/h almost completely blocked the expansion of CSDs from the place of stimulation to other gyri. After the infusions were stopped, the next CSD appeared after 10 - 15 minutes and the dynamics of the CSDs were normalized.

Conclusions: The effect of ketamine in the induction, expansion area and velocity over the gyrencephalic brain can be modified using different pharmacodynamic schemes as evaluated by in-vivo IOS.