Comparison of the effects of intravenous dexmedetomidine of different target-controlled infusion pharmacokinetic models for propofol (Marsh vs Schnider) during induction of anesthesia
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Date
2017
Authors
Siang, Tan Hai
Journal Title
Journal ISSN
Volume Title
Publisher
Pusat Pengajian Sains Perubatan, Universiti Sains Malaysia
Abstract
Background: Dexmedetomidine is selective alpha 2-agonist which is commonly used
for sedation and potential to be used as co-induction drug. The aim of this study was to
determine the effects of dexmedetomidine on induction using different target-controlled
infusion (TCI) pharmacokinetic models of propofol.
Methods: 64 patients, aged 18-60 year-old, classified under ASA I and II, who
underwent elective surgery under general anaesthesia, were randomised into two
groups; Group Marsh (n=32) and Group Schnider (n=32). All patients received 1
mcg/kg loading dose of intravenous (IV) dexmedetomidine over 10 minutes and
followed with TCI remifentanil at 2 ng /ml. After effect-site concentration (Ce) of
remifentanil achieved 2 ng/ml, TCI propofol induction was started. Group Marsh was
started with Marsh model at target plasma concentration (Cpt) of 2 mcg/ml, whereas
Schnider group was started with Schnider model at target effect concentration (Cet) of 2
mcg/ml. If induction was unsuccessful after 3 min, target concentration (Ct) was
gradually increased to 0.5 mcg/ ml every 30 seconds until succesful induction. Ct
requirement of propofol at successful induction, induction time, Ce of propofol at
successful induction and serial of haemodynamic parameters were recorded for
statistical analysisResults: Requirement of Ct of propofol for successful induction was significantly lower
in Group Schnider than Group Marsh [3.48 (0.90) vs. 4.02 (0.67) g/ml; P = 0.01].
Mean induction time was also shorter in Group Schnider than Group Marsh [134.96
(50.91) vs. 161.59 (39.64); P = 0.02] seconds. There were no significant differences in
Ce at successful induction and haemodynamic parameters between the two groups.
Conclusions: Dexmedetomidine as co-induction with TCI remifentanil and TCI
propofol reduced Ct requirement for induction and shorter induction time in Schnider
model than Marsh model of TCI propofol. However, haemodynamic effects were stable
in both groups.
Description
Keywords
Anesthetics , Intravenous