Effects of low-dose sevoflurane on infant motor evoked potentials

JRCT ID: jRCT1041230094

Registered date:18/10/2023

Basic Information

• Recruitment status: Pending
• Health condition(s) or Problem(s) studied: Spinal diseases
• Date of first enrollment: 18/10/2023
• Target sample size: 28
• Study type: Interventional

Intervention(s)

Begin general anesthesia with sevoflurane (5-8% end expiratory concentration) and laughing gas (40% concentration mixed with oxygen). After the patient is asleep, a peripheral venous tract is secured in the upper extremity. Next, to obtain an anesthetic depth suitable for tracheal intubation, an intravenous bolus of 2 mg/kg of propofol and 2 mcg/kg of fentanyl is administered, followed by tracheal intubation via an endotracheal tube. Propofol (4-6 mg/kg/h) and remifentanil (0.5-1 mcg/kg/min) with/without sevoflurane (end-expiratory concentration 0.5-1.0%) is then administered as standard anesthesia (no muscle relaxants are used for nerve monitoring to monitor muscle contractions). After tracheal intubation, the patient is placed in the supine position, a neuromonitoring device is attached, control data are recorded preoperatively, and neuromonitoring is performed and recorded as appropriate during the procedure.

The following protocol was developed to avoid exceeding this normal clinical scope.

Perform a slow induction with sevoflurane (5-8% sevoflurane under 40% laughing gas).
Once the patient is asleep, secure a peripheral venous tract in the upper extremity.
After obtaining a suitable depth of anesthesia for tracheal intubation with 2 mg/kg propofol and 2 mcg/kg fentanyl, intubation is performed.
Propofol (5 mg/kg/h) and remifentanil (0.5-0.8 mcg/kg/min) (hereafter TIVA) are started as base general anesthesia from the time tracheal intubation is completed.
Increase the dose of remifentanil if there are signs of shallow anesthetic depth (body movements or changes in vital signs).
Ensure that the patient is placed in the supine position and mechanically ventilated with fresh gas at 6 L/min or more for at least 20 minutes before measuring the control potential, and that the exhaled sevoflurane concentration on the monitor is 0.
Return the minute ventilation volume to 3 L/min and measure and record the control MEP potential
In group S (intervention group), sevoflurane at 0.1 age-adjusted MAC (0.2%-0.25% end-expiratory concentration for infants) is added to TIVA for 20 minutes under ventilation at 3 L/min. After 20 minutes, when the sevoflurane concentration is stable, again After 20 minutes, when the sevoflurane concentration stabilized, the MEP was again measured and recorded.
In the P group (control group), TIVA (propofol 5 mg/kg/h + remifentanil 0.5-0.8 mcg/kg/min) is continued for 20 minutes at 3 L/min of ventilation, and then the MEP is recorded.

Outcome(s)

• Primary Outcome: Percentage (%) of attenuation of the TOP to BOTTOM values of the MEP potential waveform (continuous variable) in the upper extrimities.
• Secondary Outcome: Percentage (%) of attenuation of the TOP to BOTTOM values of the MEP potential waveform (continuous variable) in the lower extrimities.

Key inclusion & exclusion criteria

• Age minimum: Not applicable
• Age maximum: < 1age old
• Gender: Both
• Include criteria: Spinal surgery patients scheduled for intraoperative MEP less than 1 year old

Exclude criteria

Patients with preoperative lower limb motor dysfunction (incomplete or complete paralysis)
Patients who should refrain from using inhalation anesthetics (sevoflurane)
(e.g., neuromuscular disease, history (including suspicion) of malignant hyperthermia)
Patients who cannot use propofol (e.g., egg white allergy)
Patient and family refusal for any reason
Intraoperative circulatory instability due to anesthetics administered by intraoperative intervention
If the anesthesiologist in charge (independent of the research team) determines that the protocol anesthetic agents do not provide adequate depth of anesthesia

Related Information

• Primary Sponsor: Kojima Taiki