The consent of patient’s next of kin was obtained; however, institutional review board approval was exempted because neither the ethical problem nor the description to identify the patient was included in this case report. A 21-month-old boy with acute or chronic lung disease was admitted to the intensive care unit (ICU). He was 63 cm in height and weighed 7.9 kg. He was bone on the 24th week of gestation and weighed 645 g and had been provided with home oxygen therapy with 3 L/min oxygen administration. His chest computed tomography showed several giant bullae in the bilateral lungs (Fig. 1). He had gastroesophageal reflux and an intestinal feeding tube (6.5 F) and a gastric drainage tube (6 F) indwelled.
He had been suffering from upper respiratory infection and fever for a couple of days. He gradually developed hypoxia (SpO2 < 90%) with oxygen administration. Immediately after admission, his airway was established using a cuffed 3.5-mm tracheal tube. Immediately after the beginning of mechanical ventilation, 10-cm H2O positive end-expiratory pressure (PEEP) combined with moderate pressure support (8 cm H2O) was applied.
His respiratory status gradually improved. Five days after the commencement of mechanical ventilation, finally, his trachea was extubated. Immediately after extubation, HHFNC therapy at 20 L/min with an FiO2 of 0.35 (Optiflow system™, MR850 heated humidified RT202 delivery tubing; Fisher and Paykel Healthcare Ltd., Auckland, New Zealand) was applied through nasal cannula (Optiflow™ Junior Nasal Cannula Infant; Fisher & Paykel, Auckland, New Zealand).
However, severe stridor because of upper airway obstruction was observed, then a 10-cm-long 3.5-mm hand-made nasal airway (Portex™, Smith Medical, Kent, UK) was placed in the left nostril (10 cm depth). It was not confirmed whether or not inserting the tube too deeply because he violently resisted being checked with a laryngoscopy. But, stridor or retractive breathing was not observed. Therefore, HHFNC therapy was restarted with this airway position.
HHFNC was conducted smoothly for a while; however, he became restless and then started agonizing heavily with SpO2 reduction down to 70%. Critical abdominal distention was observed, and forced gastric drainage was started through a gastric tube. However, the critical situation was not improved. A subsequent chest X-ray revealed that the nasal airway was placed too deeply (Fig. 2), and the gastrointestinal air was severely accumulated (Fig. 3).
Immediately, the nasal airway was removed and HHFNC flow was reduced to 10 L/min. Frequent suctioning and continuous gastric drainage were required, which achieved gradual improvement of respiratory condition. Finally, HHFNC therapy was successfully terminated.