Study of Rocuronium Onset Time According to Remifentanil Infusion

Study Overview
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Brief Summary
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The investigators therefore hypothesized that remifentanil could prolong the onset time of rocuronium, and evaluated the effect of remifentanil on the hemodynamic profiles (arterial pressure and heart rate) during the anesthetic induction sequence.

Detailed Description
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It has been reported that co-administration of ephedrine reduced the onset time of neuromuscular block of rocuronium (1-3). It also provided an improved condition for the rapid tracheal intubation (2,4). This beneficial effect was attributed to the increased cardiac output and tissue perfusion to muscle, and therefore, a more rapid delivery of rocuronium to the neuromuscular junction was achieved (4-5). If so, any drugs which decrease cardiac output consequently can prolong the onset time of rocuronium. Remifentanil is the first ultra-short acting opioid with a rapid onset. During the total intravenous anesthesia (TIVA) with propofol and remifentanil, prior administration of remifentanil could reduce the propofol infusion pain without other significant complications (6). However, remifentanil can decrease the arterial pressure and heart rate (7-8), so that it is likely to decrease the onset time of rocuronium for the opposite principle that ephedrine increases it. The investigators therefore hypothesized that remifentanil could prolong the onset time of rocuronium, and evaluated the effect of remifentanil on the hemodynamic profiles (arterial pressure and heart rate) during the anesthetic induction sequence.

Official Title
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The Effect of Remifentanil on the Onset Time of Rocuronium in Total Intravenous Anesthesia

Conditions
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Anesthesia

Intervention / Treatment
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* Drug: the order of drug administration


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: American Society of Anesthesiologist physical status I or II Aged 20-65 yr Elective surgery under general anesthesia with total intravenous anesthesia 8.5 kg/m2 < body mass index (BMI) < 25 kg/m2 Exclusion criteria: BMI > 25 kg/m2 or < 18.5 kg/m2 Any cardiovascular or neuromuscular disease Intake of drugs known to interact with the neuromuscular junction Patients wit risk of pulmonary aspiration Anticipated difficult airway history of known allergy to rocuronium

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: group R<br>In group R, remifentanil was infused first before administrating propofol and rocuronium | Drug: the order of drug administration<br>* In group R, remifentanil was infused first before administrating propofol and rocuronium and in group P, it was administered last after the rocuronium injection. In other words, the order of drug infusion in each group is remifentanil-propofol-rocuronium in group R and propofol-rocuronium-remifentanil in group P, respectively.<br>* Other names: fresopol;|
| Active Comparator: group P<br>in group P, remifentanil was administered last after the propofol and rocuronium injection | Drug: the order of drug administration<br>* In group R, remifentanil was infused first before administrating propofol and rocuronium and in group P, it was administered last after the rocuronium injection. In other words, the order of drug infusion in each group is remifentanil-propofol-rocuronium in group R and propofol-rocuronium-remifentanil in group P, respectively.<br>* Other names: fresopol;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the onset time of rocuronium | Onset time of rocuronium was defined as the time from the end of its injection to the 95% depression of single twitch response, and it was measured by an anaesthesiologist, unaware of the group allocation. | 3 minutes [after injection of rocuronium when general anesthesia is induced.] | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| mean arterial pressure (MAP) | before induction (baseline): When a patient enter the operating room, at rocuronium administration: immediately before injecting rocuronium, before tracheal intubation: immediately before intubation, after tracheal intubation: immediately after intubation. | 15 minutes [4 times; during the induction of general anesthesia as described below.] | 
| heart rate (HR) | before induction (baseline): When a patient enter the operating room, at rocuronium administration: immediately before injecting rocuronium, before tracheal intubation: immediately before intubation, after tracheal intubation: immediately after intubation. | 15 minutes [4 times; during the induction of general anesthesia as described below.] | 
| cardiac output | before induction (baseline): When a patient enter the operating room, at rocuronium administration: immediately before injecting rocuronium, before tracheal intubation: immediately before intubation, after tracheal intubation: immediately after intubation. | 15 minutes [4 times; during the induction of general anesthesia as described below.] | 
| pain from the propofol infusion | When propofol is administered for the induction of anesthesia, we investigate the pain by propofol. | 1 minute [at the time when propofol is administered.] | 
| cough or chest wall rigidity from the remifentanil infusion | when remifentanil is infused, the cough or chest wall rigidity is checked. | 1 minute [at the time when remifentanil is infused.] |