Optimal Dose of Combination of Rocuronium and Cisatracurium
Condition: Chronic Otitis Media; Anesthesia
MeSH terms: Otitis Media
Study type: Interventional

Summary: 
      BACKGROUND: The combinations of rocuronium and cisatracurium have a synergic effect. The
      investigators studied whether the prediction is possible to have a sufficient effect of
      reducing the dose when combining the two neuromuscular blocking agents through monitoring
      neuromuscular relaxation during surgery.

      METHODS: Each group were intubating dose group (Group I, n=27) combined Effective Dose (ED)95
      rocuronium and ED95 cisatracurium, small amount reducing group (Group S, n=27) reduced 10% of
      each ED95 and large amount reducing group (Group L, n=27) reduced 20% of each ED95. Before
      patients arrived in the operating room, rocuronium and cisatracurium were prepared by a nurse
      who was not involved in this study. Each study drug was administrated to the patient and
      timer was started with TOF-Watch® monitoring. Train-of-four (TOF) of the ulnar nerve was used
      as setting of 2 Hz per 12 sec. The investigators checked time to TOF ratio=0 (Onset), time to
      1st TOF ratio>25% (Duration 25%) and TOF 25-75% (recovery index) under total i.v. anesthesia
      (TIVA). One way ANOVA was used for statistical analysis (α=0.05, β=0.2).
    

Detailed description: 
      Introduction:

      Rocuronium and cisatracurium are representative neuromuscular blocking agents used widely
      because the former have features of fast onset of peak effect and short duration of muscle
      relaxation relatively while the latter have comparatively long duration relaxation time and
      break down by Hofmann elimination and ester hydrolysis. A combination of the two have a
      synergic effect may be also used with either the priming method for rapid sequence
      intubation. It would contribute both to determine the effective combination rate clinically
      and to predict the pharmacokinetic characteristics that determine how much the synergistic
      effect of this combination. The investigators studied whether the prediction is possible to
      have a sufficient effect of reducing the dose when combining the two muscle relaxants through
      monitoring muscle relaxation during surgery.

      Materials and methods:

      This study was conducted to 81 patients scheduled for elective mastoidectomy and
      tympanoplasty after obtaining written informed consent. All patients included the American
      Society of Anesthesiologists (ASA) physical status I-II, aged 20-60, BMI 20-30 kg/m2. The
      exclusion criteria were as follows: a history of allergy to the study drugs, neuromuscular
      disease, pregnancy or breast-feeding, preoperative medication of antipsychotics or
      neuroleptics known to interact with non-depolarizing neuromuscular blocking agents (NMBAs),
      serum creatinine level>1.2 mg/dL, liver transaminase>40 U/L. Anthropometric variables such as
      height, weight were measured in ward before surgery. BMI calculated as total body weight
      divided by the squared height. Ideal body weight (IBW) was calculated by the formula of
      Devine {50 kg + 2.3 × (height [inch]-60) for man and 45.5 kg + 2.3 × (height [inch]-60) for
      woman} and used to administrate NMBAs of initial dose. Lean body weight (LBW) was calculated
      by the formula of James {LBW (men) = (1.10 × Weight(kg)) - 128 × ( Weight2 / (100 ×
      Height(m))2), (women) = (1.07 × Weight(kg)) - 148 × ( Weight2 / (100 × Height(m))2)}.
      Additive dose of NMBAs was administrated by LBW. Patients were randomly assigned to each
      group by opening of sealed allocation envelope. Each group were intubating dose group (Group
      I, n=27) combined ED95 rocuronium and ED95 cisatracurium, small amount reducing group (Group
      S, n=27) reduced 10% of each ED95 and large amount reducing group (Group L, n=27) reduced 20%
      of each ED95.

      Monitoring and Medication:

      In the operating room, monitoring was accomplished to patients with a noninvasive blood
      pressure, pulse oximetry, electrocardiography, thermometer, Bispectral Index (BIS VISTA
      Monitoring System; Aspect Medical Systems Inc, Norwood, MA, USA), and T1/T4 ratio used
      TOF-Watch® (Organon, Teknica B.V., Boxtel, the Netherlands). Every 5 min, measured things are
      recorded.

      Premedications with midazolam 2 mg and glycopyrrolate 0.2 mg were administrated to patients
      intramuscularly 1 h before surgery. Before patients arrived in the operating room, rocuronium
      and cisatracurium were prepared by a nurse who was not involved in this study. The syringe
      containing each study drug was conveyed to the performer of this study as the status of
      shielding the scale. The syringes of rocuronium and cisatracurium used each other syringe.
      Anesthesia was induced with propofol 1.5-2.5 mg/kg, remifentanil 0.4-0.6 mcg/kg, afterward
      maintained with target controlled infusion (TCI) of propofol 5-10 mg/kg/hr and remifentanil
      0.05-2 mcg/kg/min. The infusion pump (Orchestra Module DPS, Fresenius-Vial, Brezins, France)
      was operated with Minto's and Marshall's pharmacokinetic model for effect site TCI of
      remifentanil and propofol.

      The opposite arm against operation side was used for neuromuscular monitoring and attached to
      armboard of TOF-Watch®. Each study drug was administrated to the patient and timer was
      started with T1/T4 ratio monitoring. The surface electrodes of ulnar nerve placed at the
      wrist and Train-of-four (TOF) stimulation was used as setting of supramaximal square wave
      impulses with 200μs duration, 2 Hz per 12sec. The investigators checked times to TOF ratio=0
      (Onset), 1st TOF ratio>25% (Duration 25%) and TOF 25-75% (Recovery Index), recovery time of
      90% (TOF 25-90%) under total i.v. anesthesia (TIVA). Also the investigators checked the rate
      of additional rescue dose administrated with 10% of initial NMBAs dose, operation time from
      incision to surgical wound dressing, anesthesia time from entering to going out the operation
      room. Body temperature was maintained above 35°C using warm air blanket. The arterial
      pressure cuff was placed on the opposite arm against TOF monitoring.

      Adverse Events and Management:

      In all patients, anesthesia level was assessed based on a BIS score of 40-60. Moderate
      hypertension (>120% of baseline) or hypotension (<80% of baseline) was treated by increasing
      or decreasing rate of propofol infusion with fluid supplement. Severe hemodynamic change
      (systolic pressure < 90 mmHg or > 200 mmHg) was controlled by intravenous (IV) administration
      of phenylephrine 50 mcg or nicardipine 250 mcg repeatedly until being hemodynamic stable
      status. Unexpectedly, when hiccup or self-contained respiration was showed, additional rescue
      dose of NMBAs was administrated to the patient even though T1/T4 ratio was lower than 25%.

      Statistical Analysis:

      All data are expressed as means ± standard deviations (SDs), numbers (percentages), or
      medians (upper and lower quartiles), as appropriate. Data between the groups were compared
      using the χ2 test, Fisher exact test, independent t test, or the Mann-Whitney U test, as
      appropriate. To assess data normality, the Kolmogorov-Smirnov test was performed on the data
      set. According to a preliminary study, 24 patients would be required in each group with a
      power of 0.9 and a type I error of 0.05. Factoring in a drop-out rate of 10%, the
      investigators calculated that 27 patients would be required for each group. All statistical
      analyses were performed with the SPSS 18.0 (SPSS Inc., Chicago, IL, USA) program. A P value
      <0.05 was considered statistically significant.
    

Intervention name(s): 10% reduction of combination of Esmeron® and Nimbex®; 20% reduction of combination of Esmeron® and Nimbex®
Intervention type(s): Drug; Drug
Intervention description(s): Patients were randomly assigned to each group by opening of sealed allocation envelope. After collection of data, allocation number was matched with each group. The participants matched at Group S were administered with NMBAs reduced 10% of each ED95. Before patients arrived in the operating room, rocuronium and cisatracurium were prepared by a nurse who was not involved in this study. Each drug dosage was determined by allocation number. The syringe containing each study drug was conveyed to the performer of this study as the status of shielding the scale. The syringes of rocuronium and cisatracurium used each other syringe.; The participants matched at Group L were administered with NMBAs reduced 20% of each ED95.
Other intervention name(s): Esmeron®, 74119419, ATC code:M03AC09; Nimbex®, 74500213, ATC code:M03AC11; Esmeron®, 74119419, ATC code:M03AC09; Nimbex®, 74500213, ATC code:M03AC11
Intervention MeSH terms: Rocuronium; Atracurium; Cisatracurium
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: combination; rocuronium; cisatracurium; neuromuscular blockade monitoring; drug synergism