['To present a case of severe hypercapnic respiratory failure in an adult burn patient and to describe our clinical problem solving approach during support with an unconventional mode of mechanical ventilation.', "A 19-yr-old male with smoke inhalation and flame burns to 50% total body surface area was admitted to the Ross Tilley Burn Centre. High frequency oscillatory ventilation (HFOV) was initiated on day three for treatment of severe hypoxemia. By day four, the patient met consensus criteria for acute respiratory distress syndrome. On day nine, alveolar ventilation was severely compromised and was characterized by hypercapnea (PaCO(2) 136 mmHg) and acidosis (pH 7.10). Attempts to improve CO(2) elimination by a decrease in the HFOV oscillatory frequency and an increase in the amplitude pressure failed. An intentional orotracheal tube cuff leak was also ineffective. A 6.0-mm nasotracheal tube was inserted into the supraglottic hypopharynx to palliate presumed expiratory upper airway obstruction. After nasotracheal tube placement, an intentional cuff leak of the orotracheal tube improved ventilation (PaCO(2) 81 mmHg) and relieved the acidosis (pH 7.30). The improvement in ventilation (with normal oxygen saturation) was sustained until the patient's death from multiple organ dysfunction four days later."] Do hypercapnic respiratory failure and partial upper airway obstruction during high frequency oscillatory ventilation in an adult burn patient?