The Validity and Tolerability of Awake Calibration of the TOF Watch SX Monitor (CaliRev)

The Validity and Tolerability of Awake Calibration of the TOF Watch SX® Monitor: An Interventional Prospective Single Two-center Study

Neuromuscular blocking agents (NMBAs) are frequently used in anesthesia and quantitative monitoring of neuromuscular block is standard care. Normally the calibration of the neuromuscular monitor is done after anesthesia induction to avoid patient discomfort. Under certain circumstances there is no time for the calibration process. In the so-called rapid sequence induction (RSI) the neuromuscular blocking agent has to be injected immediately after the induction agent. As the neuromuscular monitor cannot be calibrated, precise neuromuscular monitoring is not possible, and this is of particular disadvantage, when high doses of non-depolarizing neuromuscular blockers are injected to fasten the onset of neuromuscular block. The primary objective is to validate the measurements of the TOF Watch SX® monitor calibrated in awake patients by comparing them with the measurements obtained with the TOF Watch SX® monitor calibrated after anesthesia induction (Gold standard).

The secondary objective is to evaluate the tolerability of the awake calibration process of the TOF Watch SX® monitor.

Study Overview

• Status: Terminated
• Conditions: Neuromuscular Blockade
• Intervention / Treatment: Device: TOF Watch SX

Detailed Description

Neuromuscular function will be assessed by acceleromyography of the adductor pollicis with a TOF-Watch SX® monitor on both arms. By randomization it will be chosen on which arm the awake calibration will be done. 5 minutes before the awake calibration process the patients will receive 0.2 µg/kg of sufentanil intravenously. Immediately after the end of the calibration process the patients will rate the pain of the calibration process on a visual analog scale from 0 to 10. Anesthesia will then be induced and immediately at loss of consciousness continuous TOF stimulation will be continued every 12s. Then the calibration process on the other arm will be started, followed by continuous TOF stimulation. After having obtained stable baseline measurements with the TOF-Watch SX® monitor, a bolus dose of rocuronium 0.6 mg kg-1 will be administered intravenously. The trachea will be intubated when full neuromuscular block is reached. No additional rocuronium will be given. Both neuromuscular monitors will be linked via a fiber-optic (TOF-Link®) cable with UBS port to a laptop. Specific software will be used to record the measurements (TOF watch SX® monitor, version 2.2). Neuromuscular monitoring will be continued until a normalized TOF ratio of 0.9 has been obtained on both arms. The onset of neuromuscular block and its spontaneous recovery will be recorded and the results obtained on each arm will be compared. Every patient is his own control.

• Study Type: Interventional
• Enrollment (Actual): 64
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Canton Of Geneva
    • Geneva, Canton Of Geneva, Switzerland, 1211
      • University Hospital of Geneva, Anesthesia Department
  • Ticino
    • Lugano, Ticino, Switzerland, 6900
      • Ospedale Regionale di Lugano

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• American Society of Anesthesiologists class I or II
• patients undergoing elective surgery lasting at least 60 minutes under general anesthesia requiring neuromuscular blockade using rocuronium bromide for endotracheal intubation

Exclusion Criteria:

• Patient with a history of allergy or hypersensitivity to rocuronium.
• Patients with neuromuscular disease
• Patients with preoperative medications known to influence neuromuscular function (for instance aminoglycosides, phenytoin, lidocaine)
• Patients with electrolyte abnormalities (for instance, hypermagnesemia)
• Patients with a body mass index <19 or >30 kg m2
• Patient having participated in any clinical trial within 30 days, inclusive, of signing the informed consent form of the current trial
• Patients undergoing interventions that need a continuous deep neuromuscular block
• Pregnant or breast feeding women

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Awake calibration; The dominant arm of the patient	Device: TOF Watch SX; Neuromuscular monitoring via the TOF Watch SX device
Active Comparator: Asleep calibration; The non dominant arm of the patient	Device: TOF Watch SX; Neuromuscular monitoring via the TOF Watch SX device

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total recovery time	Total duration of the neuromuscular block defined as the time in minutes from start of injection of rocuronium until a normalized TOF ratio of 90%	during the duration of the general anesthesia

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Onset time	The time in seconds from start of injection of rocuronium until 95% depression of the first twitch (T1) of the TOF	during the duration of the general anesthesia
Dur TOFc1	Time in minutes from administration of rocuronium to emergence of the 1st twitch of the TOF	during the duration of the general anesthesia
Dur TOF 25%	Time in minutes from administration of rocuronium to emergence of a TOF ratio of 25%	during the duration of the general anesthesia
Dur TOF 50%	Time in minutes from administration of rocuronium to emergence of a TOF ratio of 50%	during the duration of the general anesthesia
Dur TOF 75%	Time in minutes from administration of rocuronium to emergence of a TOF ratio of 75%	during the duration of the general anesthesia
TOF pain: VAS	The pain experienced during the calibration process evaluated by a visual analogue scale from 0 to 10.	before inductin of general anesthesia

Collaborators and Investigators

• Sponsor: Christoph Czarnetzki
• Collaborators: Hôpital du Valais
• Investigators: Study Chair: Christoph A Czarnetzki, MD, University Hospital, Geneva

Study record dates

Study Major Dates

• Study Start (Actual): October 26, 2018
• Primary Completion (Actual): November 9, 2021
• Study Completion (Actual): November 9, 2021

Study Registration Dates

• First Submitted: August 24, 2018
• First Submitted That Met QC Criteria: August 27, 2018
• First Posted (Actual): August 28, 2018

Study Record Updates

• Last Update Posted (Actual): January 21, 2022
• Last Update Submitted That Met QC Criteria: January 10, 2022
• Last Verified: January 1, 2022

More Information

Terms related to this study

• Keywords: Tof Watch, rocuronium
• Other Study ID Numbers: CaliRev

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No