Purpose: To compare effects of dexmedetomidine or a subanesthetic dose of ketamine on the amplitude and latency of transcranial electrically generated motor evoked potentials. Overview of Literature: Total intravenous anesthesia (TIVA) is a standard anesthesia technique for transcranial electrical motor evoked potential monitoring in spine surgery. We aimed to determine whether the use of dexmedetomidine and ketamine as a component of TIVA exerted any beneficial effect on the quality of monitoring. Methods: A total of 90 American Society of Anesthesiologist grade I-III patients, aged 18-65 years, with a motor power of ≥4/5 grade as per the Medical Research Council Scale in all four limbs who were scheduled for elective spine surgery under transcranial electrical motor evoked potential monitoring were enrolled. The subjects were randomly allocated into the following three groups: group PD who received 0.5 µg/kg/hr dexmedetomidine infusion, group PK who received 0.5 mg/kg/hr ketamine infusion, and group PS who received normal saline infusion, along with standard propofol-fentanyl based TIVA regime. Amplitude and latency of bilateral motor evoked potentials of the tibialis anterior and abductor halluces muscle were recorded at Ti (at train-of-four ratio >90%), T30 (30 minutes post-Ti), T60 (60 minutes post-Ti), and Tf (at the end of spine manipulation). Results: Baseline median amplitudes were comparable among the study groups. In group PK, we noted a gradually enhanced response by 24%-100% from the baseline amplitude. The median amplitudes of all the muscles were higher in group PK than those in groups PS and PD at time points T60 and Tf (p<0.05).
Conclusions:The present study demonstrated that compared with dexmedetomidine and control treatment, a subanesthetic dose of ketamine caused gradual improvement in amplitudes without affecting the latency.
Dear Editor,Anisocoria in the postoperative period may indicate life-threatening conditions, and the possible causes are intracranial pathologies, Horner syndrome, acute angle closure glaucoma, ocular injury, or pharmacological blockade. 1,2 We report a unique case of postoperative anisocoria in a patient who underwent cervical spine surgery in a prone position with the patient's head secured on a head clamp.
Pregnancy in Ebstein anomaly could cause acute decompensated heart failure. Therefore, medical termination of pregnancy is the next course of action in such cases. We present a case of 25-year-old primigravida with Ebstein anomaly posted for termination of pregnancy at 8 weeks of gestation. The patient had dyspnea on minimal exertion with a recent episode of upper respiratory tract infection. Caudal epidural in place of lumbar epidural or general anesthesia was chosen in view of the recent episode of respiratory infection and minimal hemodynamic changes and early recovery of motor blockade associated with the former. Pregnancy was terminated successfully with minimal intraoperative hemodynamics variation. Hence, for minor gynecological procedure like termination of pregnancy, caudal epidural anesthesia provides an alternative option especially in cases where hemodynamic variation is least desired like decompensating congenital heart condition.
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