CASE PRESENTATION: A 42 year old male with a past medical history of subglottic tracheal stenosis and post-traumatic stress disorder presented with a two day history of progressive dyspnea and was admitted for elective tracheostomy. During his admission, patient had acute respiratory failure, requiring emergent tracheostomy. Due to extensive scarring, the patient was left with an unfinished tracheal stoma, with a temporary tube, and was transferred to the MICU. No inhalational anesthetics were utilized during tracheostomy. Due to his difficult airway, delirium, agitation, and anxiety, heavy sedation was required to maintain ventilation. He was difficult to sedate due to morbid obesity and tolerance to opiates and benzodiazepines. As such, the patient was started on Fentanyl drip, in addition to Versed, Propofol, and Precedex drips. Of note, the patient’s home Paxil had been continued on admission. The day following titration of Fentanyl to 300mcg/kg/h, patient became diaphoretic, hyperthermic, tachycardic, hypertensive, and exhibited bilateral mydriasis, tremors and clonus. Septic workup was initiated and found to be negative. Serotonin syndrome was diagnosed using Hunter’s criteria. Fentanyl and Paxil were discontinued, supportive care initiated, and Cyproheptadine was started, after which the patient had resolution of symptoms.