An 88-year-old male with a 55 pack-year smoking history and an additional past medical history of COPD, and stage IA non–small cell lung cancer was referred for bronchoscopy. Prior to the procedure the patient was alert and oriented, afebrile, with BP 130/70, RR 14, and O2 saturation of 99% while breathing room air. The patient received a total of 100 µg IV fentanyl and 4 mg IV midazolam in divided doses during the bronchoscopy. Following the airway survey the diagnostic bronchoscope was removed and the patient received an additional 100 µg of fentanyl and 1 mg of midazolam prior to insertion of the scope for endobronchial ultrasound. Two minutes after insertion of the endobronchial ultrasound bronchoscope the patient developed a clenched hand and jaw and hypertension to 225/135 mm Hg. Respiratory motion was no longer evident upon examination of his chest wall. Oxygen saturation dropped to 81%. In addition to securing the airway the next most appropriate step would be:
A. Rapidly obtain CT of the headCorrect Answer: C
This patient has likely experienced fentanyl-induced chest wall rigidity. Skeletal muscle rigidity following opiate administration, which may primarily affect the musculature of the chest and abdomen, was first described in 1953. While a rare complication of opioid analgesia, it is thought to be more commonly associated the lipophilic synthetic opioids such as fentanyl, remifentanil, and sufentanil. Risk factors include extremes of age, concurrent use of medications that alter dopamine levels, and higher doses or rapidity of injection. Skeletal muscle rigidity decreases the compliance of the chest wall and increases work of breathing or may even lead to the cessation of spontaneous breathing. Decreased chest wall compliance can also complicate efforts at mechanical ventilation. Treatment includes reversal of opioids with naloxone (answer C) or mechanical ventilation and neuromuscular blocking agents.
Head CT would be an appropriate diagnostic tool in cases of suspected stroke, but in this case the temporal association with fentanyl administration and the cessation of chest wall motion make rigidity the more likely diagnosis.
The patient developed acute hypertension along with atypical motion of the hand and arm which may suggest the possibility of hypertensive emergency. Acute therapy of hypertensive emergency is aimed at lowering of blood pressure by 10% to 20% but, in this case, the hypertension is secondary to respiratory distress.
Benztropine is indicated for therapy of dystonic reactions such as those associated with the administration of antipsychotic medications but is not the appropriate choice for the primary diagnosis here.
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