The Effect of Magnesium Sulphate on the Time Course of Rocuronium Induced Neuromuscular Block (MagRoc)

The Effect of Magnesium Sulphate on the Time Course of Rocuronium Induced Neuromuscular Block - A Randomised Electrophysiology Study

The aim of this study is to investigate whether an optimized pre-treatment with intravenous magnesium enhances the speed of onset of a standard intubation dose of rocuronium.

Study Overview

• Status: Completed
• Conditions: Neuromuscular Blockade
• Intervention / Treatment: Drug: Physiologic saline; Drug: Magnesium sulphate

Detailed Description

In a previous study pre-treatment with intravenous MgSO4 60 mg kg-1 was not shown to have any impact on the onset of action of rocuronium [Kussmann et al, 1997]. Yet, in that study, MgSO4 was injected as a bolus after induction of anaesthesia, one minute only before the injection of the neuromuscular blocking agent. We suppose that magnesium needs some time to penetrate the neuromuscular endplate and to shift the Mg/Ca ratio in favor of magnesium. Thus, the particular design of the previous study may explain why magnesium had no scope to enhance the speed of onset of action of rocuronium.

The aim of our study is to investigate whether an optimised pre-treatment with magnesium (short infusion rather than bolus injection; reasonable delay between administration of magnesium and subsequent injection of the neuromuscular blocking agent) enhances the speed of onset of a standard intubation dose of rocuronium.

1. Preanaesthetic preparation

   • Solid food and liquid intake will not be allowed for a minimum of six hours before induction
   • Patients will be premedicated with 7.5 mg oral midazolam 45 min prior to induction
   • Standard monitoring will consist of: ECG, SaO2, ETCO2, non-invasive blood pressure, rectal or oesophageal T°

2. Study drug administration

   • Intravenous infusion of the study solution, 1 ml per kg bodyweight, corresponding to MgSO4 60 mg kg-1 in the magnesium group. The infusion will be given with an Infusomat during 15 minutes.

3. Induction and maintenance of anaesthesia

   • At the end of the study drug infusion, and after a preoxygenation period of three minutes, anaesthesia will be induced with sufentanil 0.2µg kg-1 and propofol, using a Target Controlled Infusion (TCI) system (Base Primea, Fresenius-Vial, Brezins, France) and the pharmacokinetic model of Schnider et al [Schnider et al, 1999]. The initial effect site concentration will be 4 µg ml-1.
   • Maintenance of anaesthesia will be with a propofol effect site

4. Neuromuscular monitoring

   • Neuromuscular function will be monitored using the TOF Watch® SX (NV Organon) and TOF nerve stimulation. The guidelines for good clinical research practice in pharmacodynamic studies of NMBAs will be followed.
   • The ulnar nerve is stimulated through surface electrodes, and the adductor pollicis muscle response is measured.
   • After the stabilisation period, rocuronium 0.6 mg kg-1 (2 x ED95) will be injected intravenously during 5 seconds.
   • The trachea will be intubated after a 95% depression of the first twitch

5.1. Neuromuscular measurements

• Onset time = time from beginning of injection of rocuronium until a 95% depression of the first twitch (T1).
• Duration 25% = time from beginning of injection of rocuronium until 25% T1 recovery.
• Recovery index T25-75 = time between 25% T1 recovery and 75% T1 recovery.
• Clinical recovery T25 - 0.9 = time between 25% T1 recovery and TOF ratio (T1/T4) of 0.9 (corresponding to safe extubation condition).

5.2. Haemodynamics

• Blood pressure
• Heart rate These measurements will be done before (baseline), and at 5-minute intervals during the study drug infusion. Before and immediately after tracheal intubation, haemodynamic measurements will be repeated.

5.3. Adverse events, safety

• Any minor adverse event (no need for intervention) or major adverse events will be recorded.

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Phase 4

Contacts and Locations

Study Locations

• Switzerland
  • Canton of Geneva
    • Geneva, Canton of Geneva, Switzerland, 1211
      • University Hospital of Geneva, Anesthesia Department

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• American Society of Anaesthesiology (ASA) status I or II
• Adults, aged 18 years to 60 years
• Scheduled for elective surgery lasting longer than 120 min without need for continuous curarisation

Exclusion Criteria:

• A history of allergy or hypersensitivity to rocuronium
• Neuromuscular disease
• Preoperative medications known to influence neuromuscular function (for instance, certain antibiotics and anticonvulsants)
• Electrolyte abnormalities
• Hepatic or renal insufficiency
• Patients with a body mass index <19 or >28 kg m2
• Pregnant or breastfeeding women
• Expected difficult intubation or mask ventilation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Single Group Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Physiologic saline	Drug: Physiologic saline; Intravenous infusion of the study solution, 1 ml per kg bodyweight, corresponding to MgSO4 60 mg kg-1 in the magnesium group and 1 ml per kg physiological saline. The infusion will be given with during 15 minutes.
Active Comparator: Magnesium sulphate	Drug: Magnesium sulphate; Intravenous infusion of the study solution, 1 ml per kg bodyweight, corresponding to MgSO4 60 mg kg-1 in the magnesium group. The infusion will be given during 15 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To study whether a pre-treatment with MgSO4, 60 mg kg-1, administered as an intravenous infusion 15 minutes prior to induction enhances the speed of onset of a standard intubation dose of rocuronium	Onset time ist the time in seconds from start of injection of rocuronium until 95% depression of the first twitch (T1) of the Train of four (TOF)	1 to 5 minutes

Secondary Outcome Measures

Outcome Measure	Time Frame
To study whether, and to what extent, pre-treatment with MgSO4 prolongs recovery characteristics of the neuromuscular block that is induced by rocuronium	minutes to hours
To study possible haemodynamic effects of pre-treatment with MgSO4.	hours

Collaborators and Investigators

• Sponsor: University Hospital, Geneva
• Investigators: Principal Investigator: Christoph A Czarnetzki, MD, MBA, University Hospital of Geneva, Anesthesia Department; Study Chair: Martin Tramer, MD, PhD, University Hospital of Geneva, Anesthesia Department

Publications and helpful links

General Publications

• Czarnetzki C, Lysakowski C, Elia N, Tramer MR. Time course of rocuronium-induced neuromuscular block after pre-treatment with magnesium sulphate: a randomised study. Acta Anaesthesiol Scand. 2010 Mar;54(3):299-306. doi: 10.1111/j.1399-6576.2009.02160.x. Epub 2009 Nov 16.

Study record dates

Study Major Dates

• Study Start: May 1, 2006
• Primary Completion (Actual): August 1, 2008
• Study Completion (Actual): August 1, 2008

Study Registration Dates

• First Submitted: November 29, 2006
• First Submitted That Met QC Criteria: November 29, 2006
• First Posted (Estimate): December 4, 2006

Study Record Updates

• Last Update Posted (Estimate): September 19, 2011
• Last Update Submitted That Met QC Criteria: September 15, 2011
• Last Verified: September 1, 2011

More Information

Terms related to this study

• Keywords: Magnesium; Rocuronium; Neuromuscular block; Time course of action
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Anti-Arrhythmia Agents; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Anesthetics; Membrane Transport Modulators; Anticonvulsants; Calcium-Regulating Hormones and Agents; Reproductive Control Agents; Calcium Channel Blockers; Tocolytic Agents; Magnesium Sulfate
• Other Study ID Numbers: CER 05-055