Abstract Fentanyl is frequently used in the intensive care unit for procedural sedation, ventilatory synchrony, and analgesia. While common side effects of synthetic opioids are well recognized, a rare and underreported complication is fentanyl-induced chest wall rigidity, also known as "wooden chest syndrome."The largest published case series in critically ill adults identified 42 cases of suspected fentanyl-induced rigid chest syndrome but did not provide a denominator of all fentanyl-exposed ICU patients1, so a precise incidence rate is not currently available. We present a case of a patient with acute liver failure complicated by ventilator dependence who, following initiation of fentanyl, had the new onset of ventilator dyssynchrony with obvious chest wall and abdominal rigidity. A 59-year-old male with decompensated cirrhosis (decompensations included esophageal varices and hepatic encephalopathy on lactulose), and type 2 diabetes mellitus was transferred from an outside facility for liver transplant evaluation. He initially presented for acute liver failure and septic shock, with his course complicated by oliguric acute kidney injury requiring continuous renal replacement therapy. Initial ventilator settings onarrival to our hospital included pressure support of 5 cmH2O, PEEP of 5 cmH2O, and FiO2 of 35% while sedated with dexmedetomidine infusion. Fentanyl was initiated on the day of admission, starting at 50 mcg per hour and titrated to 100 mcg per hour within 15 minutes. Shortly thereafter, the patient developed ventilator dyssynchrony and intermittent apnea, with tidal volumes falling below 100 mL and elevated peak pressures. On exam, he was normotensive and unresponsive to noxious stimuli; he demonstrated vigorous chest wall and abdominal muscle activation, particularly during expiration. Despite ventilator and circuit adjustments, ventilation remained ineffective. ETCO2 rose from 27 to 40 mmHg. Point-of-care ultrasonography and chest radiography showed no acute pulmonary pathology, and bronchoscopy revealed diffusely collapsible airways but no other abnormalities. His medication list was examined for possible contributions to other common causes of rigidity in the ICU—including serotonin syndrome, neuroleptic malignant syndrome, malignant hyperthermia, and baclofen withdrawal— and none were identified. Fentanyl was discontinued and propofol was initiated, resulting in improved synchrony. Fentanyl was later reintroduced at lower doses without recurrence; naloxone was not administered as a reversal agent. This case highlights the importance of recognizing fentanyl-induced chest wall rigidity as a potential causeof ventilator dyssynchrony in critically ill patients. 1. Tammen AJ, Brescia D, Jonas D, Hodges JL, Keith P. Fentanyl-Induced Rigid Chest Syndrome in Critically IllPatients. J Intensive Care Med. 2023;38(2):196-201. doi:10.1177/08850666221115635 This abstract is funded by: None
Popovich et al. (Fri,) studied this question.