Validation of the TOF Cuff Monitor® Which Measures Neuromuscular Block on the Upper Arm
Condition: Neuromuscular Blockade
Study type: Interventional

Summary: 
      Neuromuscular blocking agents (NMBAs) are frequently used in anesthesia and quantitative
      neuromuscular monitoring is standard care. The TOF WATCH SX® monitor is considered as one of
      the reference monitoring devices in clinical research and clinical practice. With this
      monitor the ulnar nerve is stimulated at the wrist and the force of the movement of the thumb
      is measured with acceleromyography. This method requires freedom of movement of the patient's
      thumb. Unfortunately this is not always possible due to the constraints of patient
      positioning during the operation. The TOF Cuff® monitor is a modified non-invasive blood
      pressure cuff that incorporates stimulating electrodes in its inner surface and is based on
      the stimulation of the peripheral nerve in the arm (brachial plexus, ulnar and median nerves
      principally). The evoked neuromuscular activity is recorded through the changes in pressure
      generated in the inner part of the cuff by the muscular activity after the stimulus.
      Moreover, this device can be used for non-invasive reading of the blood pressure. This device
      has been validated with mechanomyography, but was never been compared with acceleromyography,
      which is the most common used neuromuscular monitoring method.
    

Detailed description: 
      Neuromuscular blocking agents (NMBAs) are frequently used in anesthesia for tracheal
      intubation, artificial ventilation, and continued muscle relaxation during surgical
      interventions. It is of particular importance to measure the neuromuscular block for several
      reasons:

        1. To monitor the onset of neuromuscular block and to intubate when deep muscular
           relaxation is attained.

        2. To choose the best antagonist and its dosage dependent of the degree of neuromuscular
           block (for instance sugammadex for deep neuromuscular block or neostigmine for
           superficial block).

        3. To avoid antagonization of neuromuscular block in the case of complete recovery of
           neuromuscular function.

      It is proven that monitoring of neuromuscular block reduces patient mortality. It avoids
      postoperative residual curarization, which is associated with complications such as
      hypoxemia, bronchoaspiration and pneumonia. Therefore the development and validation of new
      and efficacious neuromuscular monitoring devices is of great importance.

      Neuromuscular monitoring is done by stimulating with an electric current a nerve and to
      measure the response of the corresponding muscle. In clinical practice acceleromyography is
      the most often used quantitative measurement method, because it is much easier to apply than
      other established quantitative neuromuscular monitoring methods such as mechanomyograpy and
      electromyography. Acceleromyography is based on the piezoelectric effect where mechanical
      forces at play on the surfaces of certain materials, such as crystals or ceramics, induce an
      electrical current. According to Newton's second law of motion, force equals mass times
      acceleration (F=m x a). At constant mass, the acceleration measured and the voltage thereby
      generated can be used to derive the force of the stimulated muscle. It is standard practice
      to stimulate the ulnar nerve at the wrist and to measure the movement of the adductor
      pollicis. In the research setting acceleromyography (TOF Watch SX® monitor) is an established
      and widely used method. This method requires freedom of movement of the patient's thumb.
      Unfortunately this is not always possible due to the constraints of patient positioning
      during the operation. The TOF Cuff® monitor is a modified non-invasive blood pressure cuff
      that incorporates stimulating electrodes in its inner surface and is based on the stimulation
      of the peripheral nerve in the arm (brachial plexus, ulnar and median nerves principally).
      The evoked neuromuscular activity is recorded through the changes in pressure generated in
      the inner part of the cuff by the muscular activity after the stimulus. Moreover, this device
      can be used for non-invasive reading of the blood pressure. This device has been validated
      with mechanomyography, but was never been compared with acceleromyography, which is the most
      common used neuromuscular monitoring method.
    

Intervention name(s): Tof cuff; Tof Watch SX
Intervention type(s): Device; Device
Intervention description(s): The Tof Cuff will be installed on one arm. After anesthesia induction the Tof Cuff will be calibrated and continuos monitoring of the neuromuscular block started until complete recovery of neuromuscular block.; The Tof Watch SX will be installed on the opposite arm to the Tof Cuff. After anesthesia induction the Tof Watch SX will be calibrated and continuos monitoring of the neuromuscular block started until complete recovery of neuromuscular block.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Validation study for a neuromuscular monitoring device