Dr. Saenz is a staff anesthesiologist and Dr. Guruli is chief of Anesthesiology Service, both at G.V. (Sonny) Montgomery VAMC in Jackson, Mississippi. Dr. Saenz and Dr. Guruli also are both assistant professors of anesthesiology at the University of Mississippi Medical Center in Jackson.
An attempt to place an oral intubation bite block failed, because the stiff EMG tube proved too difficult to pass through it. Therefore, the EMG tube and rolled gauze pads placed between the upper and lower teeth were used to protect the fiberoptic bronchoscope while it was guided past the base of the tongue. As was noted in the CT scan, the airway was deviated slightly to the left, and this information was useful for guiding the fiberscope. The location of the epiglottis was fairly difficult to ascertain due to redundant tissue in the hypopharyngeal area but was ultimately visible through the fiberscope.
The vocal cords were not visible, possibly due to the significant amount of airway edema and/or redundant tissue between the epiglottis and the vocal cords: Only the space beneath the epiglottis could be seen via the fiberscope. Passing the bronchoscope through the larynx also was problematic due to what may be described as altered spatial/angular relationships and due to the supraglottic edema/tissue leaving little room for the tip of the bronchoscope to be maneuvered. Figure 3 shows a CT scan image of the supraglottic area.
It took 45 minutes and multiple attempts to pass the bronchoscope into the trachea. The dexmedetomidine infusion was continued throughout this entire sequence. The patient tolerated this manipulation with little difficulty, despite the multiple airway maneuvers, and his hemodynamic and respiratory status remained clinically stable. Oxygen saturation was 95% to 100% during this sequence and the patient did not show evidence of significant upper airway collapse, desaturation, or apnea, which are sometimes encountered during sedation for airway manipulation.
The patient’s hemodynamic status remained near baseline values throughout the airway manipulation. The patient never lost his ability to cooperate. After manipulation of the fiberscope into the trachea, the tracheal rings and carina were visualized, and the tube was advanced over the scope. Minimal to mild coughing occurred once the tube passed through the vocal cords. The tube position in the trachea was verified with end-tidal CO2 and bronchoscopy and then the induction of anesthesia with propofol was completed. A laryngoscopy using a videolaryngoscope confirmed proper EMG electrode placement. Large-bore IV access and an arterial line were then secured.
The operation lasted about 15 hours. Maintenance of anesthesia was accomplished with the use of the volatile anesthetic desflurane, titrated to patient response to the surgical procedure. Additionally, 550 μg of IV fentanyl was used intermittently during the operation. Dexmedetomidine was infused at a rate of 0.2 to 0.4 μg/kg/h during the anesthetic, titrated to hemodynamic response. All hemodynamic parameters remained stable and within 20% of preoperative levels during the procedure. The blood loss during the procedure was minimal (< 100 mL), and acceptable readings from the EMG tube were confirmed throughout the surgical procedure.
The 686-gram thyroid mass was confirmed to be a multinodular goiter. Due to the difficulty with intubation, the length of the surgical procedure, and the likelihood of airway difficulties from edema possibly requiring reintubation, the patient was left intubated and mechanically ventilated overnight and sedated with a dexmedetomidine infusion of 0.3 μg/kg/h and propofol 35 mL/h. No further medications were required. He tolerated the ventilator without fighting, straining, coughing, or hypertensive responses and remained cooperative when aroused. He was successfully extubated the following day. Afterward, the patient maintained his airway and had only a mild right vocal cord paresis complicating his surgical management.
Discussion
The critical issues associated with this successful endotracheal intubation included the patient’s obesity, thyroid mass size, and deviation/compression of the trachea. Were this patient morbidly obese only, airway management would still be problematic; this was exacerbated by the concurrent pathologies. Dexmedetomidine possesses several advantageous properties for the perioperative period and was chosen as sedation for the awake intubation due to its sedative-analgesic effects, opioid sparing effects, lack of respiratory depression, maintenance of patient cooperation, and antisialagogue effect.2-5 Dexmedetomidine has previously been shown to be useful for awake intubation of difficult airway cases.4,6,7 Importantly, the dexmedetomidine sedation seemed to blunt the hypertensive responses often seen during airway maneuvers.8 It was also chosen as an intraoperative adjunct due to the above-noted opioid-sparing effects, given the importance of minimizing perioperative opioids needed for this morbidly obese individual with airway compromise.
In the literature, dexmedetomidine has been shown to greatly reduce the need for opioids, both intraoperatively and immediately postoperatively in many citations, for example, in postoperative mechanically ventilated coronary artery bypass graft patients.2,9 Opioid usage reduction is especially needed for the morbidly obese who are at increased risk of OSA and the attendant increased sensitivity to the respiratory depressant effects of narcotics. Postoperative opioids are being debated in the literature as potentially being a risk factor for cancer recurrence due to the effects on the immune system.5,10
