on the patient’s condition and a communication between the anesthesiologist, surgeon and interventional radiologist is essential. C. Voscopoulos et al. and Basem Abdalmalak et al. have successfully used dexmedetomidine based technique in tracheobronchial stenting in the cases of central airway obstruction. Bergese SD et al. evaluated the safety and efficacy of dexmedetomidine for sedation during awake fiberoptic intubation and they found that dexmedetomidine is effective as the primary sedative in the patients undergoing the awake fiberoptic intubation with difficult airway. In our case, as the patient was not able to lie down, it was challenging to maintain the airway as well as to make the anxious patient comfortable. Dexmedetomidine possesses anxiolytic, sedative, analgesic, and sympatholytic properties. The Federal Drug Administration has approved the use of dexmedetomidine as a sedative-analgesic and/or total anesthetic in adults and pediatric patients undergoing small minimally invasive procedures, with or without the need for tracheal intubation. It is a safe sedative alternative to benzodiazepine/ opioid combinations in the patients undergoing monitored anesthesia care for a multitude of procedures because of its analgesic, “cooperative sedation,” and lack of respiratory depression properties. Dexmedetomidine, coupled with local anesthesia, provided excellent sedative and operative conditions for awake laryngeal framework procedures. To conclude, dexmedetomidine along with adequate airway anesthesia can be an alternative in awake tracheal stenting. Samarjit Dey, Prithwis Bhattacharyya, Jayanta Medhi1, Adarsha Karadi Nellappa Department of Anaesthesiology, 1Otolaryngology, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGRIHMS), Shillong, Meghalaya, India Address for correspondence: Dr. Samarjit Dey, Department of Anaesthesiology, NEIGRIHMS, Shillong, PIN - 793 018, Meghalaya, India. E-mail: [email protected]
References 1. 2.
Ramamani M, Raj S, Manickam P. Anaesthesia for tracheo-bronchial stenting-a report of two cases. Indian J Anaesth 2008;52211. Voscopoulos C, Kirk FL, Lovrincevic M, Lema M. The use of “High Dose” dexmedetomidine in a patient with critical tracheal stenosis and anterior mediastinal mass. Open Anesthesiol J 2011;5:42-9. Abdelmalak B, Marcanthony N, Abdelmalak J, Machuzak MS, Gildea TR, Doyle DJ. Dexmedetomidine for anesthetic management of anterior mediastinal mass. J Anesth 2010;24:607-10. Bergese SD, Candiotti KA, Bokesch PM, Zura A, Wisemandle W, Bekker AY, et al. A Phase IIIb, randomized, double-blind, placebocontrolled, multicenter study evaluating the safety and efficacy of
dexmedetomidine for sedation during awake fiberoptic intubation. Am J Ther 2010;17:586-95. Grewal A. Dexmedetomidine: New avenues. J Anaesthesiol Clin Pharmacol 2011;27:297-302. Access this article online Quick Response Code:
Tongue bite injury after use of transcranial electric stimulation motor-evoked potential monitoring Sir, Monitoring of motor-evoked potential (MEP) during spine surgery is considered a safe technique but potential hazards include bite injuries, possibility of hazardous stimulator output, patient movement induced injury, seizures, cardiac dysrhythmias, and epidural electrode-related complications. Tongue and lip bite injuries are the most common reported complications during MEP monitoring with an incidence ranging from 0.2% to 0.63%.[1,2] Previous case reports have reported bite injuries including minor tongue lacerations, broken teeth, and even bitten endotracheal tube. Thirty-seven-year-old, ASA physical status I, male with BMI 24.3 Kg/m2, was posted for L3-4 laminectomy and excision of L3 intradural tumor in the prone position with transcranial electric stimulation (TES) MEP monitoring. After induction of anesthesia and intubation, the endotracheal tube was taped to the right side and a soft bite block (rolled up gauze) was inserted in the midline. Surgery and anesthesia were uneventful and lasted two hours. Tracheal extubation was performed in the OR but the patient was mildly sedated. Postoperative examination of the oral cavity revealed a tongue hematoma on the left side [Figure 1]. He was reassured about the self-resolving nature of the hematoma and was advised oral care regimen. Risk factors for tongue injury during TES MEP monitoring include C3-4 focused stimulation that directly activates the temporalis muscle and prone position (as in our patient) as it predisposes to tongue swelling. The mechanism of tongue injury may involve both corticobulbar activation with
Address for correspondence: Dr. Aparna Williams, Department of Anesthesiology, Christian Medical College and Hospital, Vellore - 632 004, Tamil Nadu, India. E-mail: [email protected]
References 1. 2.
3. 4. 5.
Figure 1: Tongue hematoma
pulse-trains and direct muscle or trigeminal nerve stimulation, because jaw-clenching also occurs with single pulses. Use of C3/4 TES might produce stronger biting than C1/2 TES because the electrodes are closer to facial motor cortex, jaw muscles, and trigeminal nerves. Placement of a bite block is standard practice during MEP monitoring, but it does not necessarily prevent injury to oral structures as is evident in our case. Tongue injury due to bite block dislodgement and movement of the tongue between the teeth has been reported earlier. There is no consensus on the type and number of bite blocks to reduce these injuries. Most reviewers suggest the use of soft bite blocks[1,5] as rigid bite blocks may cause pressure injury to the tongue and lingual nerve and dental trauma. The use of three soft bite blocks (one in between the molars on each side and one in the centre) and dental guards on the mandibular and maxillary dental lines with a soft bite block in between have been suggested. Frequent intraoperative checking of the position of the bite block and the tongue has been recommended but this may be difficult if the patient is in the prone position, as in our case. All anesthesiologists need to be aware of and discuss the risk of injury to structures of the oral cavity when using TES MEP monitoring with the patient. Careful assessment for tracheal extubation is warranted in cases at high risk for injury, as an injured and swollen tongue may cause airway obstruction and need for re intubation. The use of less frequent and low voltage stimulation, correct placement of bite blocks, and continued vigilance to their position can go a long way in preventing patient bite injuries during TES MEP monitoring. Aparna Williams, Georgene Singh Department of Anesthesiology, Christian Medical College, Vellore, Tamil Nadu, India 440
MacDonald DB. Intraoperative motor evoked potential monitoring: Overview and update. J Clin Monit Comput 2006;20:347-77. Tamkus A, Rice K. The incidence of bite injuries associated with transcranial motor-evoked potential monitoring. Anesth Analg 2012;115:663-7. Deiner SG, Osborn IP. Prevention of airway injury during spine surgery: Rethinking bite blocks. J Neurosurg Anesthesiol 2009;21:68-9. Lam AM, Vavilala MS. Macroglossia: Compartment syndrome of the tongue? Anesthesiology 2000;92:1832-5. Pajewski TN, Arlet V, Phillips LH. Current approach on spinal cord monitoring: The point of view of the neurologist, the anaesthesiologist and the spine surgeon. Eur Spine J 2007;16(Suppl 2):S115-29. Mahmoud M, Spaeth J, Sadhasivam S. Protection of tongue from injuries during transcranial motor-evoked potential monitoring. Pediatr Anaesth 2008;18:902-3. Access this article online Quick Response Code:
Induction and intubation in a Kleeblattschadel syndromic child with posterior cranial distractors Sir, Posterior external cranial distractors are used for surgical correction in patients with craniosynostoses. Presence of a posterior external cranial distractor is challenging to the anesthesiologists as the child cannot be placed supine, even for intubation. This female child was born with an abnormally shaped large head and was diagnosed to have Kleeblattschadel syndrome, hydrocephalus, and pancraniosynostoses. Anterior craniofacial reconstruction was done at 2 months and posterior cranial expansion with foramen magnum decompression at 4 months. External distractors were placed for posterior cranial fossa expansion at 8 months. Now, 1-year-old and posted for posterior external cranial distractor removal in prone position.
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To evaluate the relationship between stimulus intensity by constant current transcranial electric stimulation and interstimulus interval (ISI) for eliciting muscle motor evoked potentials (MEPs) in three different hand muscles and the tibialis anteri
Transcranial direct current stimulation (tDCS) causes a complex spatial distribution of the electric current flow in the head which hampers the accurate localization of the stimulated brain areas. In this study we show how various anatomical features
To develop a pipeline for realistic head models of nonhuman primates (NHPs) for simulations of noninvasive brain stimulation, and use these models together with empirical threshold measurements to demonstrate that the models capture individual anatom
Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. We measured electric potentials intrac
Transcranial electric stimulation (TES) is an emerging technique, developed to non-invasively modulate brain function. However, the spatiotemporal distribution of the intracranial electric fields induced by TES remains poorly understood. In particula
Transcranial magnetic stimulations (TMS) have been used for many years as a diagnostic tool to explore changes in cortical excitability, and more recently as a tool for therapeutic neuromodulation. We are interested in their applications following br
Postactivation depression of the Hoffmann (H) reflex is associated with a transient period of suppression following activation of the reflex pathway. In soleus, the depression lasts for 100-200 ms during voluntary contraction and up to 10 s at rest.
After focal brain injuries occur, in addition to the effects that are attributable to the primary site of damage, the resulting functional impairments depend highly on changes that occur in regions that are remote but functionally connected to the si
We applied a low-intensity pulsed transcranial ultrasound stimulation (pTUS) to the ischemic cortex after a distal middle cerebral artery occlusion (dMCAO) to study whether pTUS is capable of protecting brain from ischemic injury.