The objective of this study is to evaluate the effect of adding dexmedetomidine on evoked potentials in adult patients undergoing spinal surgery under intravenous anesthesia
A catastrophic complication of spinal surgery is nerve and spinal cord injury. The incidence of neurological defects after spinal surgery can be reduced from 3.7%-6.9% to less than 1% with proper electrophysiological monitoring. Somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) are currently used as adjunct diagnostic methods in spinal surgery, such as scoliosis surgery and spinal stenosis decompression. Total intravenous anesthesia (TIVA) with propofol and opioids is commonly used in SEPs and MEPs monitoring as it causes increase in latency in comparison to inhalational anesthetics that cause decrease in amplitude . The amplitudes of MEPs and SEPs are reduced by halogenated volatile anesthetics, limiting their use in spinal surgery that requires electrophysiological monitoring. When volatile anesthetics did not exceed 0.3MAC, they had little effect on MEPs and SEPs . Martin et al. discovered that volatile agent-based anesthesia has application value during neurophysiological monitoring, such as faster awakening and rapid wake-up tests. As well, volatile anesthetics can reduce the dosage of propofol. As a result, spinal surgery benefits from combined intravenous inhalation anesthesia. As an adjuvant, dexmedetomidine may be useful in reducing the need for propofol. Dexmedetomidine is a potent and highly selective alpha-2 agonist. It has the effect of sedation, analgesia, sympatholytic, minimal respiratory depression and possible neuroprotection. Its addition to the anesthetic regimen is believed to have the potential of sparing other hypnotics requirement, especially propofol, thus facilitating MEP and SSEP monitoring while providing the beneficial effects it has.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
78
Anesthesia will be induced with propofol (2mg/kg) and fentanyl (1 ug/kg). Anesthesia will be maintained with propofol and fentanyl infusion, commenced at 10 mg/kg/hr and 0.5 ug/kg/hr respectively and adjusted to keep BIS between 40 \& 50 during surgery. Minimal dose of atracurium 0.1 mg/kg will be given at induction to facilitate intubation.
Anesthesia will be induced with propofol (2mg/kg) and fentanyl (1 ug/kg). Anesthesia will be maintained with propofol and fentanyl infusion, commenced at 10 mg/kg/hr and 0.5 ug/kg/hr respectively and adjusted to keep BIS between 40 \& 50 during surgery. In addition patients will receive Dexmedetomidine (0.5ug.kg) loading dose infused over 10 mins followed by a constant infusion rate of (0.2ug/kg/hr). Minimal dose of atracurium 0.1 mg/kg will be given at induction to facilitate intubation.
Anesthesia will be induced with propofol (2mg/kg) and fentanyl (1 ug/kg). Anesthesia will be maintained with propofol and fentanyl infusion, commenced at 10 mg/kg/hr and 0.5 ug/kg/hr respectively and adjusted to keep BIS between 40 \& 50 during surgery. In addition the anesthesia will be maintained with inhalational anesthesia of 50% oxygen , 50% air plus sevoflurane concentration adjusted to keep BIS between 40 \& 50 . Minimal dose of atracurium 0.1 mg/kg will be given at induction to facilitate intubation
Ain Shams University
Cairo, Egypt
The amplitude score of Somato sensory evoked potential
The amplitude score of the waveforms will be measured. More than 50% decrease in the amplitude and more than 10% prolongation of the latency of Compound muscle action potential ( CMAP) from the baseline values will be defined as significant
Time frame: 6 hours postoperatively
The latency of Somato sensory evoked potential
The latency of the waveforms will be measured. More than 50% decrease in the amplitude and more than 10% prolongation of the latency of Compound muscle action potential (CMAP) from the baseline values will be defined as significant
Time frame: 6 hours postoperatively
The latency of motor evoked potential
The latency of the waveforms will be measured. More than 50% decrease in the amplitude and more than 10% prolongation of the latency of Compound muscle action potential (CMAP) from the baseline values will be defined as significant
Time frame: 6 hours postoperatively
The amplitude score of motor evoked potential
The amplitude of the waveforms will be measured. More than 50% decrease in the amplitude and more than 10% prolongation of the latency of Compound muscle action potential (CMAP) from the baseline values will be defined as significant
Time frame: 6 hours postoperatively
Intraoperative fentanyl consumption
Fentanyl (1 ug/kg) will be used to induce anesthesia.
Time frame: Intraoperatively
Intraoperative propofol consumption
Propofol (2mg/kg) will be used to induce anesthesia
Time frame: Intraoperatively
Intraoperative dexmedetomidine consumption
Dexmedetomidine (0.5ug/kg) loading dose infused over 10 mins followed by a constant infusion rate of (0.2ug/kg/hr)
Time frame: Intraoperatively
Intraoperative sevoflurane consumption
the anesthesia will be maintained with inhalational anesthesia of 50% oxygen , 50% air plus sevoflurane concentration adjusted to keep BIS between 40 \& 50
Time frame: Intraoperatively
Changes in heart rate
Heart rate will be assessed immediately before the operation and every 10 minutes in the first 30 minutes of the operation then every 15 minutes till the end of the operation.
Time frame: Till the end of operation
Changes in mean arterial pressure
Mean arterial pressure will be assessed immediately before the operation and every 10 minutes in the first 30 minutes of the operation then every 15 minutes till the end of operation
Time frame: Till the end of operation
Quality of surgical field
Quality of surgical field will be evaluated every 15 minutes using the surgical field rating (SFR) scale of six points : 5 - massive uncontrollable bleeding, 4 - heavy but controllable bleeding that significantly interfered with dissection, 3 - moderate bleeding that moderately compromised surgical dissection, 2 - moderate bleeding - a nuisance but without interference with accurate dissection, 1 - bleeding, so mild it was not even a surgical nuisance, 0 - no bleeding and virtually bloodless field. Surgical field was graded as good, fair, and poor as: good - SFR scale 0 or 1, fair - SFR scale 2or 3, poor - SFR scale 4 or 5).
Time frame: Till the end of operation
Intraoperative bleeding
Intraoperative bleeding will be measured by collecting blood in a marked container of 2500 ml capacity and the blood soaked by gauze pieces \[4×4 soaked gauze piece (15 ml blood), completely soaked abdominal towel (150 ml blood)\]
Time frame: Intraoperatively
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.