Rapid tracheal intubation with atracurium: the timing principle

Determination of dose and efficacy of atracurium for rapid sequence induction of anesthesia: A randomised prospective study

Background and Aims:

Succinylcholine and high dose rocuronium are neuromuscular blocking agents commonly used for rapid sequence induction of anesthesia. Their usage is limited or contraindicated in some circumstances. The aim of this study is to determine the dosage and efficacy of atracurium without priming for rapid sequence induction of anesthesia.

Material and Methods:

One hundred fifteen surgical patients under general anesthesia were randomised into three groups. All patients were given 2-3 mg/kg propofol and 1 μg/kg fentanyl intravenously for the induction of anesthesia followed by different doses of atracurium (0.6 mg/kg, 0.75 mg/kg or 1 mg/kg) without a priming dose. Tracheal intubation was performed within one minute after the administration of the study drugs. The intubating conditions, vocal cord movement and diaphragm movement were graded as the primary endpoints. Statistical analysis was done using one-way analysis of variance (ANOVA) and Post Hoc tests.

Results:

Atracurium doses of 1 mg/kg, 0.75 mg/kg, and 0.6 mg/kg provided 51.4%, 43.6% and 26.3% success rates of intubation without coughing or bucking, respectively (P = 0.03). The intubating conditions were graded as excellent or good in 86.5% of the 1 mg/kg atracurium group patients and in 84.6% of the 0.75 mg/kg group patients (P < 0.05). An atracurium dose of 1 mg/kg facilitated significant differences in vocal cord and diaphragm paralysis compared with the dose of 0.6 mg/kg (P = 0.03).

Conclusion:

The administration of a relatively high dose of atracurium without priming can be used as an alternative neuromuscular blocking agent for rapid sequence induction of anesthesia in some circumstances.

Drug Order in Rapid Sequence Intubation

BACKGROUND

The optimal order of drug administration (sedative first vs. neuromuscular blocking agent first) in rapid sequence intubation (RSI) is debated.

OBJECTIVE

We sought to determine if RSI drug order was associated with the time elapsed from administration of the first RSI drug to the end of a successful first intubation attempt.

METHODS

We conducted a planned secondary analysis of a randomized trial of adult ED patients undergoing emergency orotracheal intubation that demonstrated higher first-attempt success with bougie use compared to a tracheal tube + stylet. Drug choice, dose, and the order of sedative and neuromuscular blocking agent were not stipulated. We analyzed trial patients who received both a sedative and a neuromuscular blocking agent within 30 seconds of each other who were intubated successfully on the first attempt. The primary outcome was the time elapsed from complete administration of the first RSI drug to the end of the first intubation attempt, a surrogate outcome for apnea time. We performed a multivariable analysis using a mixed-effects generalized linear model.

RESULTS

Of 757 original trial patients, 562 patients (74%) met criteria for analysis; 153 received the sedative agent first, and 409 received the neuromuscular blocking agent first. Administration of the neuromuscular blocking agent before the sedative agent was associated with a reduction in time from RSI administration to the end of intubation attempt of 6 seconds (95% confidence interval = 0 to 11 sec).

CONCLUSION

Administration of either the neuromuscular blocking or the sedative agent first are both acceptable. Administering the neuromuscular blocking agent first may result in modestly faster time to intubation. For now, it is reasonable for physicians to continue performing RSI in the way they are most comfortable with. If future research determines that the order of medication administration is not associated with awareness of neuromuscular blockade, administration of the neuromuscular blocking agent first may be a logical default administration method to attempt to minimize apnea time during intubation.

The Role of Bolus Injection of Saline with Arm Elevation on Rocuronium onset Time: A Randomized Control Study

Background:

The onset time of neuromuscular blockade is a crucial time associated with the risk of hypoxia and pulmonary aspiration. Various strategies have been undertaken to shorten this onset time. Therefore, we investigated the effects of bolus of 20 ml saline followed by limb elevation after administration of rocuronium in a dose of 0.6 mg/kg to study the onset time.

Methodology:

Thirty patients were randomly allocated to the bolus saline group or control group. General anesthesia was induced and maintained with fentanyl and propofol. Rocuronium 0.6 mg/kg intravenous (IV) was administered followed by 20 ml saline bolus and limb elevation in the study group compared to administration of 0.6 mg/kg in a running drip only in the control. Onset of neuromuscular block was assessed by acceleromyography at the adductor pollicis muscle with train-of-four stimulation.

Results:

The lag time was shorter in bolus group (34 s median) than in control group (45 s median), P < 0.017. The onset time was shorter in bolus group (55 s median) than in control group (110 s median), P < 0.001. The T1 recovery to 25% was longer in bolus group (42 min median) than in control group (39 min median) which was statistically not significant.

Conclusion:

Rocuronium 0.6 mg/kg IV followed by bolus 20 ml saline and concomitant limb elevation resulted in shorter lag time, faster onset of neuromuscular blockade, good intubating conditions without prolonging clinical duration of action when compared to the control.

Effectiveness of the timing principle with high-dose rocuronium during rapid sequence induction with lidocaine, remifentanil and propofol

PURPOSE

The main purpose of this study was to examine the effectiveness of the timing principle with 1 mg kg(-1) rocuronium for rapid sequence intubation. As secondary outcomes, propofol and lidocaine with or without remifentanil were examined to note their effects on the cardiovascular responses to laryngoscopy and intubation.

METHODS

Thirty patients were randomly allocated to one of two groups of 15 patients each: a lidocaine-treated group (L) and a lidocaine/remifentanil-treated group (LR). Thirty seconds after lidocaine 1 mg kg(-1) with or without infusion of remifentanil 1 microg kg(-1) min(-1), all patients received a bolus of rocuronium 1 mg kg(-1). Shortly afterwards, patients were given propofol 2-2.5 mg kg(-1). Intubating conditions and cardiovascular responses were observed 60 s after rocuronium. The time to spontaneous recovery of visible train-of-four (TOF) counts of 4 was observed at the thumb during 1.0-1.5% end-tidal sevoflurane and remifentanil anesthesia.

RESULTS

All patients had excellent or good intubating conditions. Hypertension and tachycardia during laryngoscopy were well prevented in group LR, whereas they were significantly observed in group L. The times to reappearance of TOF counts of 4 were comparable in all groups [mean (SD); 63.6 (8.6) min in group L and 63.5 (11.6) min in group LR].

CONCLUSION

Application of the timing principle with 1 mg kg(-1) rocuronium is beneficial for rapid tracheal intubation. Co-administered lidocaine, remifentanil and propofol can definitely suppress cardiovascular responses during laryngoscopy and intubation.

Wirkortäquilibration, Anschlagzeit, „time to peak effect“

Contrary to the situation in "classical" clinical pharmacology, non-steady state phenomena play a fundamental role for clinical pharmacology in anesthesia. Their understanding is of tantamount importance for the safe and efficient application of drugs relevant to anesthesia. Concepts like optimised target-controlled infusion (TCI), effect compartment targeting and the small margin of error tolerable during maintained spontaneous ventilation, force the anesthesiologist to acquire a firm understanding of the difference between the concentration time course at the effect side vs. time course of the plasma concentration. The underlying concepts, their application for the rational use of muscle relaxants, propofol with TCI systems, volatile anaesthetics and opioids will be discussed.

Advances in airway pharmacology. Emerging trends and evolving controversy

The practice of emergency medicine is a constant onslaught of decision making and challenges and the issues of airway management are no exception. Obtaining proper airway control requires thoughtful organization and planning, and necessitates a thorough working knowledge of the drugs or medications employed. Because there are so many agents available, expertise in airway pharmacology has become essential. The emergency physician who is well versed in the uses, and the physiologic effects, contraindications, and alternatives of drugs administered is both providing immediate intervention and positively affecting patient outcome, which is certainly a goal worth achieving.

Tracheal intubation with rocuronium using the "timing principle"

We compared the endotracheal intubating conditions after rocuronium, using the "timing principle," with those after succinylcholine. The timing principle entails administration of a single bolus dose of nondepolarizing muscle relaxant, followed by an induction drug at the onset of clinical weakness. Forty-five patients were randomly assigned to three groups. Patients allocated to Groups 1 and 2 received rocuronium 0.6 mg/kg. At the onset of clinical weakness (onset of ptosis), anesthesia was induced with thiopental 4-6 mg/kg; intubation was accomplished after 45 s in Group 1 and after 60 s in Group 2. Patients in Group 3 received vecuronium (0.01 mg/kg) 3 min before the administration of thiopental and succinylcholine 1.5 mg/kg, and their tracheas were intubated 60 s later by a blind anesthesiologist. Intubating conditions were assessed according to a grading scale and were either good (5 patients in Groups 1 and 2, 4 patients in Group 3) or excellent (10 patients in Groups 1 + 2, 11 patients in Group 3) in all patients. Patients were interviewed postoperatively, and all were satisfied with the induction of anesthesia. We conclude that rocuronium 0.6 mg/kg provides good to excellent intubating conditions 45 and 60 s after the induction of anesthesia using the timing principle.

IMPLICATIONS

We compared the ease with which a breathing tube could be placed in patients using three techniques. The standard technique (succinylcholine) was compared with two others in which a muscle-relaxing drug (rocuronium) was administered just before the anesthetic drug (so-called timing principle). No difference among the techniques was observed.