Tracheal intubating conditions using propofol and remifentanil target-controlled infusion: a comparison of remifentanil EC50 for Glidescope and Macintosh

Joe

et al. 2013

BackgroundLidocaine is a useful intravenous and topical adjunct to facilitate tracheal intubation. We evaluated the effect of tracheal lidocaine on tracheal intubating conditions without neuromuscular blocking agent and hemodynamics during anesthesia induction with propofol and remifentanil target-controlled infusion (TCI).MethodsFifty patients, aged 18-60 years, scheduled for closed reduction of fractured nasal bone were randomly assigned to the control group (n = 25) or lidocaine group (n = 25). Anesthesia was induced with propofol-remifentanil TCI with the effect-site concentration of 5 µg/ml and 5 ng/ml. Four minutes after the start of propofol-remifentanil TCI, 4% lidocaine or saline 3 ml was instilled to larynx and trachea, and intubation was performed 1 min later. Acceptable intubation was defined as excellent or good intubating conditions. Hemodynamic data, induction and recovery profiles were recorded.ResultsIntubating condition was clinically acceptable in 13 out of 25 (52%) patients in the control group and in 22 out of 25 (88%) in the lidocaine group, and there was a significant difference between the two groups in regard to acceptable intubating conditions (P = 0.005). Mean arterial pressure change over time was significantly different between the two groups. There were no significant differences in the heart rate between the two groups.ConclusionsThis study demonstrated that laryngotracheal administration of 4% lidocaine could increase the percentage of acceptable conditions for tracheal intubation during propofol and remifentanil anesthesia without neuromuscular blockade.

Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Effect of tracheal lidocaine on intubating conditions during propofol-remifentanil target-controlled infusion without neuromuscular blockade in day-case anesthesia

Joe

et al. 2013

“…Many studies have been conducted to find the concentration of propofol required for appropriate unconsciousness when intravenous anesthesia was performed. Ithnin et al [14] reported that propofol concentration for adequate tracheal intubating condition was 3.0 µg/ml with remifentanil effect target concentration 4.41 ng/ml. Another study reported effect-site concentration of propofol for maintaining 41.1 ± 2.5 of bispectral index (BIS) value was 3.5 µg/ml [15].…”

Section: Discussionmentioning

confidence: 99%

The EC₅₀of remifentanil to minimize the cardiovascular changes during head holder pinning in neurosurgery

Seok

et al. 2012

BackgroundDuring neuroanesthesia, head holder pinning commonly results in sympathetic stimulation manifested by hemodynamic changes, such as increased heart rate and arterial blood pressure. Remifentanil has been used successfully to control acute autonomic responses during neurosurgical procedures. The objective of this study was to determine effect-site concentration of remifentanil for suppressing the hemodynamic response to head holder pinning with the probability of 50% (EC50).MethodsForty-one ASA physical status I or II patients, between the ages of 20-70, who were scheduled for neurosurgery were recruited into this study. After arrival in the operating room, standard monitoring was applied throughout the study, which included a bispectral index monitor. Both propofol and remifentanil were administered by Target-control infusion device. The Dixon "up-and-down" sequential allocation method was used to determine the EC50 of remifentanil.ResultsThe EC50 of remifentanil was 2.19 ± 0.76 ng/ml by the turning point estimate (TPE). In probit analysis, EC50 was 2.42 ng/ml (95% CI : -0.62-4.66) and EC95 was 5.70 ng/ml (95% CI : 4.02-67.53). The EC50 estimator comes from isotonic regression is 2.90 ng/ml (95% CI : 1.78-3.65). The EC95 estimator comes from isotonic regression is 4.28 ng/ml (95% CI : 3.85-4.41).ConclusionsThis study showed that EC50 of remifentanil was 2.19 ± 0.76 ng/ml by TPE. EC50 was 2.42 ng/ml (95% CI -0.62-4.66) in probit analysis, as back up analysis. The EC50 estimator comes from isotonic regression is 2.90 ng/ml (95% CI : 1.78-3.65).

“…The first patient was tested at an effect-site concentration of remifentanil 4.5 ng/ml. This was a target concentration close to the predicted remifentanil concentration at which there was a 50% probability of acceptable tracheal intubation (EC50) using a Macintosh laryngoscope [10]. If intubation was unacceptable, the target effect-site concentration of remifentanil for the next patient was increased by 0.5 ng/ml.…”

Section: Methodsmentioning

confidence: 99%

Comparison of effect-site concentration of remifentanil for tracheal intubation with the lightwand and laryngoscopy during propofol target-controlled infusion

Min

et al. 2011

BackgroundTarget-controlled infusion (TCI) of propofol and remifentanil can provide satisfactory intubating conditions without a neuromuscular blocking agent. We compared the effect-site concentration of remifentanil required for intubation with the lightwand and the Macintosh laryngoscope during propofol TCI without a neuromuscular blocking agent in adult patients.MethodsForty-nine patients were randomly assigned to the lightwand group (n = 25) or the direct laryngoscope group (n = 24). Anesthesia was induced by propofol TCI with an effect-site concentration of 5.4 µg/ml. Two minutes after start of propofol TCI, remifentanil was administered at the predetermined effect-site concentration. The effect-site concentration of remifentanil was determined using Dixon's up-and-down method (0.5 ng/ml as a step size). The first patient in each group was tested at 4.5 ng/ml of remifentanil. Tracheal intubation was performed 2 min after the start of remifentanil TCI. Acceptable intubation was defined as an excellent or good intubating conditions.ResultsUsing a modified Dixon's up and down method, the EC50 ± SD of remifentanil in the lightwand and laryngoscope groups was 4.75 ± 0.71 ng/ml and 5.08 ± 0.52 ng/ml, respectively; there was no statistically significant difference between the groups (P = 0.373).ConclusionsThe effect-site concentration of remifentanil for acceptable intubation with the lightwand and Macintosh laryngoscope in 50% of adults did not differ during propofol TCI without a neuromuscular blocking agent.