Comparison of Two Monitors That Measure Neuromuscular Function During Surgeries
Condition: Neuromuscular Blockade
Study type: Observational

Summary: 
      Anesthesiologists are often required to give certain drugs, called muscle relaxants to the
      patients for surgery. These drugs make the people weak for the procedure to make the work of
      the surgeon easier and prevent unexpected movements. The effect of these drugs must be
      terminated by the end of the procedures to ensure that the patients can breathe normally.
      Over the years several monitors have been developed to monitor the effect of these drugs. The
      monitors use different principles to measure muscle function. Some monitors are integrated
      into anesthesia machines while others are battery-operated, portable devices. The aim of the
      present study is two compare monitors using different technologies. Both monitors stimulate a
      peripheral nerve at the wrist that makes the thumb twitch. The older device (TOF-Watch SX)
      measures the acceleration of thumb movement, the new device (TetraGraph) measures the
      electrical activity of the muscle that moves the thumb. The two devices will be connected so
      that with one simulation both types of signals can be recorded and analyzed. The monitors
      will be used during the surgeries as described by the manufacturer. The study will not
      influence the surgical procedure or the anesthetic of the patients. The aim of the study is
      to collect data on how the two monitors correlate, since they measure neuromuscular function
      by different technologies (acceleromyography and electromyography).
    

Detailed description: 
      The aim of this single center, one-arm, observational, prospective, non-inferiority study is
      to compare neuromuscular data obtained with two neuromuscular monitors. The two monitors are
      the electromyography-based TetraGraph neuromuscular monitor and the acceleromyography-based
      TOF-WATCH SX device.

      The study will enroll 50 patients undergoing elective surgeries that require muscle
      relaxation. Patients will be only enrolled after written informed consent is obtained.
      Exclusion criteria include: neuromuscular disease in patient history, patient taking any
      medication that affects neuromuscular transmission, open wound or sores at the site of
      electrode placement, expected difficult airway, pregnancy or breastfeeding state, or
      implanted pacemaker.

      The study will be conducted using one of the patient's arms. Both neuromuscular monitors will
      be applied on the same arm. The monitors will be connected by optical cable link to
      synchronize nerve stimulation and data recording. The aim of this setting is to obtain both
      acceleromyography and electromyography signals of the adductor pollicis muscle in response to
      ulnar nerve stimulation. This setting ensures identical stimulation conditions for the two
      monitors. Only the TOF-Watch SX will be used for nerve stimulation while the TOF-Watch will
      collect acceleromyography data of the thumb and TetraGraph will collect the electromyography
      data of the adductor pollicis muscle.

      The ulnar nerve will be stimulated via single use electrocardiography electrodes used by
      TOF-Watch SX. The piezoelectric probe of TOF-Watch SX will be applied on the thumb via hand
      adapter, according to the manufacturer's instructions. The stimulating electrodes of
      TetraGraph will be isolated, since the device will not deliver electrical stimulation, only
      register the compound muscle action potentials of the adductor pollicis muscle evoked by
      TOF-Watch SX stimulation. The sensing electrodes of TetraGraph will be applied above the
      thenar and the interphalangeal joint of the thumb.

      The TetraGraph monitor used for the study has a modified software compared to the
      commercially available monitors. This study device is used only for the current study.

      Also, the cable of the TOF-Watch SX monitor has been modified to connect to the TetraGraph
      monitor for synchronization . The results of the responses analyzed by the TetraGraph device
      will not be used for clinical care decisions.

      Neuromuscular monitoring will be started after the induction of anesthesia before the
      administration of neuromuscular blocking agent and terminated at the extubation of the
      patient. After calibration, the TOF-Watch will be left to stimulate automatically every 15
      sec. Neuromuscular monitoring will be performed during surgery according to clinical
      standards, it will be stopped before extubation to avoid patient discomfort associated with
      neurostimulation.

      During deep neuromuscular block the examiner will deliver post tetanic count stimulation
      every 5 min.

      TOF-Watch SX data will be stored on a laptop computer using the devices software. TetraGraph
      is using a built-in SD card for data collection.

      Beside acceleromyography and electromyography train-of-four ratios, train-of-four counts and
      post tetanic counts the following data will be recorded in a clinical research form:

        -  date of surgery, type of surgery,

        -  patient identification number, patient's sex, weight, height, BMI, dominant hand side,

        -  time of anesthesia induction, drugs used to induce anesthesia

        -  time of starting neuromuscular monitoring

        -  time of muscle relaxant administration, type and dose of muscle relaxant

        -  time of tracheal intubation and extubation,

        -  time of beginning and end of surgery

        -  time of reversal agent administration, type and dose of reversal agent

        -  use of surgical devices

      To avoid uncertainty, only the data of TOF-Watch SX will be provided to the anesthesiology
      team for clinical use. TetraGraph data will be kept blinded from healthcare providers. All
      clinical decisions will be made according to TOF-Watch SX measurements, as per current
      clinical care. If any doubt arises regarding the reliability of the data delivered by
      TOF-Watch SX, the anesthesia workstations' built-in NMT modules (Infinity Trident NMT
      Smartpod, Draeger, Lübeck, Germany) will be used to guide clinical care.

      Propofol target control infusion with bispectral index monitoring will be used to provide
      anesthesia. The administration of muscle relaxants, reversal agents and time of intubation
      and extubation will be at the discretion of the attending anesthesiologist as per usual
      clinical routine.

      All patients will be monitored postoperatively for one day to detect any unexpected adverse
      events.

      Statistical analysis:

      Data will be analyzed offline after the completion of the study. Based on a priori sample
      size calculation, 50 patients will be enrolled in the study. Paired T-test and Bland-Altman
      analysis will be performed to examine the agreement between the two devices.
    

Intervention name(s): neuromuscular blockade monitoring
Intervention type(s): Device
Intervention description(s): Neuromuscular blockade monitoring via two different types of monitoring devices
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients of the University of Debrecen Clinical Center who are scheduled for elective
        surgery
      
Keywords: neuromuscular monitoring; acceleromyography; electromyography