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

Optimal effective-site concentration of remifentanil for sedation during plate removal of maxilla

Background

Removal of the plate following Le Fort I osteotomy and BSSO (bilateral sagittal split osteotomy) is a common procedure. However, patients who undergo plate removal experience intense pain and discomfort. This study investigated the half-maximal effective concentration (Ce₅₀) of remifentanil in the prevention of plate removal pain under sedation using dexmedetomidine.

Methods

The study evaluated 18 patients, between 18 and 35 years of age, scheduled for elective surgery. Remifentanil infusion was initiated after sedation using dexmedetomidine, and started at a dose of 1.5 ng/mL on the first patient via target-controlled infusion (TCI). Patients received a loading dose of 1.0 µg/kg dexmedetomidine over 10 min, followed by a maintenance dose of 0.7 µg/kg/h. When the surgeon removed the plate, the patient Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score was observed.

Results

The Ce of remifentanil ranged from 0.9 to 2.1 ng/mL for the patients evaluated. The estimated effect-site concentrations of remifentanil associated with a 50% and 95% probability of reaching MOAA/S score of 3 were 1.28 and 2.51 ng/mL, respectively.

Conclusions

Plate removal of maxilla can be successfully performed without any pain or adverse effects by using the optimal remifentanil effect-site concentration (Ce₅₀, 1.28 ng/mL; Ce₉₅, 2.51 ng/mL) combined with sedation using dexmedetomidine.

Remifentanil Requirement for Inhibiting Responses to Tracheal Intubation and Skin Incision Is Reduced in Patients With Parkinson's Disease Undergoing Deep Brain Stimulator Implantation

BACKGROUND

Parkinson's disease (PD) is a common neurodegenerative disease affecting the quality of life in the elderly. We speculated that PD patients might have abnormal pharmacodynamics due to the degenerative neural system, and the present study was performed to investigate the pharmacodynamics of remifentanil in PD patients.

MATERIALS AND METHODS

Two arms of patients were recruited, including 31 PD patients undergoing pulse generator placement after deep brain stimulator implantation and 31 pair-controlled patients undergoing intracranial surgery without PD (NPD). Patients were anesthetized with target-controlled infusion of propofol and remifentanil. The effective concentration of remifentanil to inhibit responses to intubation and skin incision in 50% and 95% patients (EC50 and EC95) was determined by the up and down method.

RESULTS

Demographic data, bispectral index, and hemodynamic values were similar between the PD and the NPD groups. The average remifentanil concentration used in the PD group for tracheal intubation is significantly lower than in the NPD group (P<0.001). The EC50 for inhibiting the response to tracheal intubation were 1.86 ng/mL (95% confidential interval [CI], 1.77-1.96 ng/mL) in the PD group and 3.20 ng/mL (95% CI, 3.13-3.27 ng/mL) in the NPD group. The average remifentanil concentration used in the PD group for skin incision is significantly lower than in the NPD group (P<0.001). EC50 for inhibiting the response to skin incision were 2.17 ng/mL (95% CI, 2.09-2.25 ng/mL) in the PD group and 3.09 ng/mL (95% CI, 3.02-3.17 ng/mL) in the NPD group.

CONCLUSIONS

The remifentanil concentrations required for inhibiting responses to tracheal intubation and skin incision are reduced markedly in PD patients undergoing pulse generator placement (NCT01992692).

Hemodynamic effects of topical lidocaine on the laryngoscope blade and trachea during endotracheal intubation: a prospective, double-blind, randomized study

PURPOSE

Minimizing hemodynamic changes during the peri-intubation period is a concern for anesthesiologists. We investigated the effect of lidocaine sprayed on the laryngoscope blade and trachea on hemodynamics during direct laryngoscopic intubation.

METHODS

Seventy-two patients were randomly allocated to one of four groups: 10% lidocaine was sprayed either on the laryngoscope blade (group L), on the trachea (group V), or on the laryngoscope blade and the trachea (group LV). No lidocaine was used in group C. Anesthesia was induced in all patients with remifentanil (effect site concentration: 4.0 ng/ml) and propofol (effect site concentration 4.0 μg/ml) continuous infusion using a target control infusion (TCI) device. Mean arterial pressure (MAP) and heart rate (HR) were recorded during the peri-intubation period.

RESULTS

Changes in MAP and HR over time were markedly different among the four groups (P < 0.05). MAP at 1 min post-intubation was significantly lower in groups L, V, and LV than in group C (86.1 ± 12.7, 85.3 ± 12.6, and 83.7 ± 13.1 vs. 106.3 ± 22.9 mmHg, P < 0.01). Maximum MAP values were lower in groups L and LV than in group C (P < 0.05). HRs at 1, 2, and 3 min post-intubation were lower in group LV than in group C (70.4 ± 9.0 vs. 84.2 ± 15.3; 64.0 ± 8.1 vs. 79.2 ± 15.4; 61.6 ± 8.3 vs. 77.2 ± 14.5 beats/min, P < 0.01, respectively).

CONCLUSIONS

Lidocaine sprayed on the laryngoscope blade and/or trachea reduced the hemodynamic response to laryngoscopic intubation during the post-intubation period following anesthetic induction with remifentanil and propofol using a TCI device.

Optimal effect-site concentration of remifentanil when combined with dexmedetomidine in patients undergoing cystoscopy

Background

Cystoscopic procedure is a very common practice in the field of urology due to its ability to survey the bladder for a variety of indications. However, patients who undergo cystoscopy feel intense pain and discomfort. This study investigated the half maximal effective concentration (EC₅₀) of remifentanil in preventing cystoscope insertion pain under sedation using dexmedetomidine.

Methods

The study was prospectively conducted on 18 male patients, aged 18 to 65. Remifentail infusion was initiated together with dexmedetomidine, and started at a dose of 2.4 ng/ml on the first patient. The effect-site concentration (C_e) of remifentanil for each subsequent patient was determined by the previous patient's response using Dixon's up-and-down method with an interval of 0.3 ng/ml. Patients received a loading dose of 1.0 µg/kg dexmedetomidine over 10 minutes, followed by a maintenance dose of 0.6 µg/kg/hr. After the patient's OAA/S score (Observer's Assessment of Alertness/Sedation scale) reached 3-4, and the C_e of remifentanil reached target concentration, the urologist was allowed to insert the cystoscope and the pain responses were observed.

Results

The effect-site concentration of remifentanil required to prevent cystoscope insertion pain in 50% of patients under sedation using dexmedetomidine was 1.30 ± 0.12 ng/ml by Dixon's up-and-down method. The logistic regression curve of the probability of response showed that the EC₅₀ and EC₉₅ values (95% confidence limits) of remifentanil were 1.33 ng/ml (1.12-1.52 ng/ml) and 1.58 ng/ml (1.44-2.48 ng/ml), respectively.

Conclusions

Cystoscopic procedure can be carried out successfully without any pain or adverse effects by optimal remifentanil effect-site concentration (EC₅₀, 1.33 ng/ml; EC₉₅, 1.58 ng/ ml) combined with sedation using dexmedetomidine.