High-frequency oscillatory ventilation (HFOV) is an alternative mode of ventilatory support for patients with severe adult respiratory distress syndrome (ARDS) failing conventional ventilation. Reported complications include pneumothorax, pneumomediastinum, and subcutaneous emphysema. While necrotizing tracheobronchitis (NTB) has been widely reported in the pediatric literature with a reported incidence between 4–44%, it is rare in adults. We report a case of NTB associated with HFOV.
A 41-year-old previously healthy Ecuadorian male was taken to the operating room with signs and symptoms consistent with an acute appendicitis. He was found to have a normal appendix. On the fifth hospital day, broad spectrum antibiotics were initiated for a fever to 103 and diffuse bilateral infiltrates on his chest radiograph. A chest CT scan revealed diffuse interstitial infiltrates with mediastinal adenopathy. A biopsy of an enlarged supraclavicular lymph node was performed. On the 8th hospital day, he was transferred to the Intensive Care Unit and intubated for hypoxemic respiratory failure. On the same day, his lymph node biopsy revealed anaplastic T-cell lymphoma for which chemotherapy was initiated. He remained on the ventilator through five days of neutropenia with no improvement. With the resolution of his neutropenia, his condition deteriorated with worsening hypoxemia despite optimal ventilator support. After an unsuccessful trial of prone ventilation, High Frequency Oscillatory Ventilation (HFOV Sensor Medics Adult HFOV 3100B) with Nitric Oxide (NO) was initiated. On the 28th hospital day the patient developed hypercapnea prompting an urgent bronchoscopy which revealed a bronchial mucosa replaced by dry, hemorrhagic, eschar-like debris nearly occluding the airway. Extensive bronchoscopic debridement was required on a daily basis. Numerous evaluations of tissue and bronchoalveolar specimen were negative for bacterial, fungal, viral etiologies. Cytology was negative for lymphoma. As inadequate humidification was postulated to be causing this condition, changes were made to the ventilator circuit to optimize humidification. Over the next seven days, surveillance bronchoscopy revealed dramatic improvement of the tracheobronchial mucosa. Unfortunately, the patient’s ARDS and overall clinical condition was unremitting despite aggressive measures. He continued to decline and died after 30 days of mechanical ventilation.
Only eleven adult cases of NTB have been reported, with nine associated with High Frequency Jet Ventilation (HFJV) and two with conventional ventilation. A combination of inadequate humidification, sub-mucosal ischemia, and high operating pressures has been implicated as an etiology of this disorder. In neonates, NTB has been associated with life-threatening airway obstruction and death with most cases identified at autopsy. In recent review of HFOV by Derdak (1), NTB is not listed as a potential complication. To our knowledge, this is the first case of NTB reported in association with HFOV. Perhaps as HFOV is utilized more frequently as an alternate mode, NTB will become better recognized as a potential complication.
In patients being placed on HFOV, maintaining an adequately humidified circuit is essential. An urgent bronchoscopy is indicated for a sudden onset of unexplained hypercapnea. Reversal of this disorder is possible with identification and management of the precipitating factors. Once identified, frequent bronchoscopy may be necessary secondary to distal bronchial obstruction caused by the sloughing of necrotic debris. This diagnosis seems to portend a grim prognosis. All of the adult cases reported died as a result of or shortly after detection of NTB.
K.K. Chung, None.