Impact of various anesthetic regimens on motor-evoked potentials in infants undergoing spinal surgery: A case series.

Motor-evoked potential (MEP) monitoring is commonly used in children. MEP monitoring in infants is difficult due to smaller signals requiring higher stimulation voltages. There is limited information on the effect of different anesthetics on MEP monitoring in this age group. This case series describes the effect of different anesthetic regimens on MEP monitoring in infants. Patients <1 year of age who underwent spinal surgery with MEP monitoring between February 2022 and July 2023 at a single tertiary care children hospital were reviewed. The motor-evoked potential amplitudes were classified into 4 levels based on the voltage in the upper and lower limbs (none, responded, acceptable, sufficient). "Acceptable" or "sufficient" levels were defined as successful monitoring. A total of 19 infants were identified, involving 3 anesthesia regimens: 4/19 (21.1%) cases were anesthetized with propofol/remifentanil total intravenous anesthesia (TIVA), 3/19 (15.8%) with propofol/remifentanil/low-dose sevoflurane and another 12/19 (63.2%) cases who initially received propofol/remifentanil/sevoflurane and were converted to propofol/remifentanil anesthesia intraoperatively. The 4 cases with propofol/remifentanil showed 20/32 (62.5%) successful monitoring points. In contrast, 6/24 (25%) successful points were achieved with propofol/remifentanil intravenous anesthesia/0.5 age-adjusted minimum alveolar concentration sevoflurane. In 12 cases converted from propofol/remifentanil/low-dose inhalational anesthetics to TIVA alone, successful MEP monitoring points increased from 46/96 (47.9%) to 81/96 (84.4%). Adding low-dose inhalation anesthetic to propofol-based TIVA suppresses MEP amplitudes in infants. The optimal anesthetic regimen for infants requires further investigation.

Anesthesia management of neonates and infants requiring intraoperative neurophysiological monitoring: A concise review.

Intraoperative neurophysiological monitoring is currently used to prevent intraoperative spinal cord and nerve injuries during neonatal and infant surgeries. However, its use is associated with some issues in these young children. The developing nervous system of infants and neonates requires higher stimulation voltage than adults to ensure adequate signals, thereby necessitating reduced anesthesia dose to avoid suppressing motor and somatosensory-evoked potentials. Excessive dose reduction, however, increases the risk of unexpected body movement when used without neuromuscular blocking drugs. Most recent guidelines for older children and adults recommend total intravenous anesthesia with propofol and remifentanil. However, the measurement of anesthetic depth is less well understood in infants and neonates. Size factors and physiological maturation cause pharmacokinetics differences compared with adults. These issues make neurophysiological monitoring in this young population a challenge for anesthesiologists. Furthermore, monitoring errors such as false-negative results immediately affect the prognosis of motor and bladder-rectal functions in patients. Therefore, anesthesiologists need to be familiar with the effects of anesthetics and age-specific neurophysiological monitoring challenges. This review provides an update regarding available anesthetic options and their target concentration in neonates and infants requiring intraoperative neurophysiological monitoring.

Bradycardia with sevoflurane in siblings with Branchio-oto-renal syndrome.

Branchio-oto-renal syndrome (BOR, Melnick-Fraser syndrome, MIM#113650) refers to a rare autosomal dominant disorder characterized by branchial cysts or fistulas, hearing loss, external ear malformation, preauricular pits and renal abnormalities. The authors present three episodes of significant bradycardia in two siblings diagnosed with BOR syndrome during the sevoflurane general anesthesia. There is no published experience of anesthesia with this syndrome. Bradycardia occurred variously at induction, maintenance and immediately prior to emergence and required surgical stimulation, atropine, or epinephrine to treat. We seek to raise awareness of the potential for bradycardia during the procedures in patients with this syndrome requiring volatile anesthesia, especially sevoflurane.