Drug-administration sequence of target-controlled propofol and remifentanil influences the onset of rocuronium. A double-blind, randomized trial

Effects of prophylactic atropine on the time to tracheal intubation with the pre-administration of remifentanil

BACKGROUND

Pre-administration of remifentanil in target-controlled propofol and remifentanil anaesthesia could prolong the time of onset of muscle relaxation owing to haemodynamic effects, thereby prolonging the time to tracheal intubation. Although the sympatholytic effects of remifentanil result in bradycardia and hypotension, these responses can be attenuated by the administration of atropine. Therefore, we investigated whether prophylactic administration of atropine could prevent the prolongation of the time to tracheal intubation.

METHODS

Sixty-four patients were included in this study. They were randomised into Group A (atropine 0.5 mg, n = 32) and Group S (saline 0.9%, n = 32), immediately before the pre-administration of remifentanil. The primary outcome was the time to tracheal intubation and the secondary outcomes were rocuronium onset time, time to loss of consciousness (LOC), time to reach a value of 60 on the bispectral index (BIS) and haemodynamic variables.

RESULTS

The median [Interquartile range] of the time to tracheal intubation was 240 [214, 288]s in Group S and 190 [176, 212]s in Group A(median difference: 50 s, 95% confidence interval: 27-80 s, P = .001). Rocuronium onset time was significantly decreased in Group A compared to that in Group S (129 [110, 156] vs 172 [154, 200], P = .001). The times to LOC and reach 60 on the BIS were not significantly different between the two groups. Cardiac output(CO) and heart rate were less decreased in Group A than in Group S (P = .02, P < .001, respectively).

CONCLUSIONS

Prophylactic administration of atropine could compensate for the reduction in CO in cases pre-administered with remifentanil in target-controlled propofol and remifentanil anaesthesia. This in turn prevented the prolongation of rocuronium onset time and reduced the time to tracheal intubation.

Pre-administration of remifentanil in target-controlled propofol and remifentanil anesthesia prolongs anesthesia induction in neurosurgical patients: A double-blind randomized controlled trial

BACKGROUND

Pre- and co-administration of remifentanil in target-controlled propofol and remifentanil anesthesia are the most common methods in clinical practice. However, anesthesia induction time by timing remifentanil administration was not identified. Therefore, we investigated the induction time of anesthesia based on type of remifentanil administration in target-controlled anesthesia.

METHODS

A total of 60 patients were randomly assigned to 1 of 2 groups: Pre-administered with remifentanil before propofol infusion (Group R, n = 30) and co-administered with remifentanil with propofol (Group N, n = 30). The primary outcome was total induction time based on the order of remifentanil administration. Secondary outcomes were from start of the propofol infusion time to loss of consciousness (LOC), rocuronium onset time, time to Bispectral index (BIS) 60, and hemodynamic variables.

RESULTS

The mean ± SD of total induction time was 180.5 ± 49.0 s in Group N and 246.3 ± 64.7 s in Group R (mean difference: 65.8 seconds; 95% CI: 35.0-96.5 s, P < .01). Time to BIS 60 and rocuronium onset time were longer in the Group R (P < .01 and P < .01, respectively). The Δheart rate and Δcardiac output values were lower in the Group R (P = .02 and P = .04, respectively). Injection pain was reported by 11 of 28 (39%) in the Group N and in 2 of 28 (7%) in the Group R (difference in proportion: 32%, 95% CI: 10-51%, P = .01).

CONCLUSION

Pre-administration of remifentanil in target-controlled propofol and remifentanil anesthesia prolongs total induction time about 35% compared to co-administration of remifentanil and propofol by decreased CO.

Optimal neuromuscular blocking effects of remifentanil during tracheal intubation under general anesthesia

Objective

This study was performed to determine the effect of the remifentanil dose on the onset time of rocuronium with electromyography.

Methods

This retrospective comparative study included 75 patients undergoing general anesthesia for elective surgery. Patients received lidocaine (40 mg) and propofol (2 mg/kg) followed by rocuronium (0.6 mg/kg) with either saline infusion (Group S), remifentanil at 0.5 µg/kg/minute (Group R 0.5), or remifentanil at 1.0 µg/kg/minute (Group R 1.0). Neuromuscular block was monitored by train-of-four (TOF) electromyography, and the times taken to reach TOF 0 and TOF ratio (TOFR) 25% were recorded.

Results

The times taken to reach TOF 0 and TOFR 25% were significantly higher in Groups R 0.5 and R 1.0 than in Group S. The time taken to reach TOF 0 was 130.0 ± 6.4 s in Group S, 142.6 ± 6.0 s in Group R 0.5, and 183.0 ± 11.6 s in Group R 1.0. The time taken to reach TOFR 25% was also higher in Groups R 0.5 and R 1.0 than in Group S.

Conclusions

As the remifentanil dose increases, the intubation time required to reach TOF 0 also increases. Remifentanil has an effect on the onset of rocuronium.

Rapid Sequence Intubation in Traumatic Brain-injured Adults

Deciding on proper medication administration for the traumatic brain injury (TBI) patient undergoing intubation can be daunting and confusing. Pretreatment with lidocaine and/or vecuronium is no longer recommended; however, high-dose fentanyl can be utilized to help blunt the sympathetic stimulation of intubation. Induction with etomidate is recommended; however, ketamine can be considered in the proper patient population, such as those with hypotension. Paralysis can be performed with either succinylcholine or rocuronium, with the caveat that rocuronium can lead to delays in proper neurological examinations due to prolonged paralysis. Recommendations for post-intubation continuous sedation medications include a combination propofol and fentanyl in the normotensive/hypertensive patient population. A combination midazolam and fentanyl or ketamine alone can be considered in the hypotensive patient.

Effects of single-shot and steady-state propofol anaesthesia on rocuronium dose-response relationship: a randomised trial

BACKGROUND

Similar to volatile anaesthetics, propofol may influence neuromuscular transmission. We hypothesised that the administration of propofol influenced the potency of rocuronium depending on the duration of the administration.

METHODS

After consent, patients scheduled for elective surgery randomly received rocuronium either after induction of anaesthesia with propofol (2 min of propofol, n = 36) or after 30 min of propofol infusion (30 min of propofol, n = 36). Remifentanil was given in both groups. Neuromuscular monitoring was performed by calibrated electromyography. The dose-response relationship of rocuronium was determined with a single-bolus technique (0.07, 0.1, 0.15, 0.2, 0.3 and 0.45 mg/kg rocuronium). The primary endpoints were the ED50 and ED95 of rocuronium after 2 and 30 min propofol. Data are presented as means with (95% confidence interval). The trial is registered with the Eudra-CT: 2009-012815-16.

RESULTS

A total of 72 patients were included. Time to maximal neuromuscular blockade was significantly shorter in patients after 30 min of propofol [3.3 min (2.9-3.7)] compared with patients anaesthetised with 2 min of propofol [4.6 min (4.0-5.2)]. After 30 min of propofol, the slope of the dose-response curve was significantly steeper (30 min of propofol: 4.34 [3.62-5.05]; 2 min of propofol: [3.34 (2.72-3.96)], resulting in lower ED95 values of rocuronium (30 min of propofol: 0.287 mg/kg [0.221-0.368]; 2 min of propofol [0.391 mg/kg (0.296-0.520)]. The ED50 were not different between groups.

CONCLUSION

The potency of rocuronium was significantly enhanced after propofol infusion for 30 min. Estimates of potency those are usually determined during steady-state anaesthesia might underestimate rocuronium requirements for endotracheal intubation at the time of induction.

Influence of a modified propofol equilibration rate constant (k(e0)) on the effect-site concentration at loss and recovery of consciousness with the Marsh model

This study compared the predicted effect-site concentration of propofol at loss and recovery of consciousness when using target-controlled infusion devices with the same pharmacokinetic model (Marsh) but a different plasma effect-site equilibration rate constant (ke0 ), the Diprifusor(TM) (ke0 0.26 min(-1) ) and Base Primea™ (ke0 1.21 min(-1) ). We studied 60 female patients undergoing minor gynaecological surgery under general anaesthesia. Although the total dose of propofol and time until loss of consciousness were comparable, the effect-site concentration at loss of consciousness was significantly lower with the Diprifusor than with the Base Primea (1.2 (0.3) μg.ml(-1) vs 4.5 (0.9) μg.ml(-1) , respectively, p < 0.001). The effect-site concentration at recovery of consciousness was significantly higher with the Diprifusor than with the Base Primea (1.8 (0.4) μg.ml(-1) vs 1.5 (0.2) μg.ml(-1) , respectively, p = 0.01). In conclusion, the effect-site concentration of propofol differs depending on the ke0 , despite the use of the same pharmacokinetic model. Therefore, the ke0 should be considered when predicting loss and recovery of consciousness based on the effect-site concentration of propofol.

[Storage at room temperature does not change cisatracurium onset time: a prospective, randomized, double-blind controlled study]

OBJECTIVE

Storage of cisatracurium at room temperature seems to have no effect on its degradation in vitro contrary to the recommendations of storage at +4°C. The purpose of this study was to evaluate the influence of cisatracurium' s storage temperature on its onset time.

STUDY DESIGN

Prospective, randomized, double-blind trial study.

PATIENTS AND METHODS

Thirty patients were enrolled. The control group consisted of 15 patients receiving cisatracurium (0.15mg/kg) stored at room temperature and the intervention consisted of 15 patients receiving cisatracurium (0.15mg/kg) stored at +4°C. The primary endpoint was to compare cisatracurium onset time depending on the storage temperature.

RESULTS

Cisatracurium onset time was 235 (180-292) seconds in the "room temperature" group vs. 240 (210-292) seconds in the "refrigerated" group. There was no difference between the onset of cisatracurium depending on the temperature of storage (p=0.51). Subgroups analysis in the "room temperature" group did not show any difference in cisatracurium onset depending on whether it was stored at room temperature for one, two or three weeks. Excellent intubation score was obtained for 100% of the patients.

CONCLUSION

This study demonstrated that cisatracurium's storage at room temperature had no influence on its onset time. It provides an argument for the preservation of cisatracurium at room temperature for a period not exceeding 21 days. Monitoring the onset of curarization may increase the quality score of intubation.