OXYGEN therapy is widely used to prevent and treat postoperative hypoxemia. For oxygen supply, the nasal catheter is popular because of its simplicity, patient comfort, economics, and safeness. This report describes a life-threatening upper airway obstruction associated with the development of submucosal emphysema caused by oxygen therapy with a nasopharyngeal catheter. Other complications after oxygen therapy with nasal catheters are reviewed.

A 63-yr-old man (weight, 80 kg; height, 160 cm) was admitted in emergency to the surgical department for acute ischemia of his right leg. Preoperative chest radiograph showed cardiomegaly, pulmonary vascular congestion, and a right lower lobe infiltration. Physical examination showed obesity, hypoventilation on the right pulmonary base, and ischemia of his right leg. Thrombectomy with general anesthesia was planned. In addition to standard monitoring, a catheter was placed in the radial artery for blood pressure monitoring. After induction of anesthesia, an uneventful tracheal intubation was performed with a soft-cuffed tube (8.0-mm ID). Anesthesia was maintained with isoflurane in a mixture of nitrous oxide, 60%, in oxygen supplemented with fentanyl and vecuronium. Ventilation was adjusted to obtain end-tidal carbon dioxide at 3.5–4.5%, and the peak airway pressures noted were never >25 cm H2O. A nasogastric tube was inserted through the right nostril without difficulty and was left in place for the postoperative period. At the end of surgery, neuromuscular blockade was reversed, and the patient was allowed to breath 100% oxygen until recovery of anesthesia. At extubation, the patient was alert, and there was no respiratory distress. In the postanesthesia care unit, oxygen 5 l/min was administered with a nasopharyngeal catheter inserted through the left nostril. Several attempts of blind tracheal suctioning were performed through the left nostril to clear abundant bronchial secretions. The introduction of the suction catheter was technically difficult, and the attempts were performed with resistance. Blood was noticed in the aspiration fluid. After aspiration, the nasal catheter had to be reintroduced through the left nostril for oxygen administration. After a few minutes, the patient became suddenly dyspneic and cyanotic. He was agitated, and inspiratory stridor was noticed. The patient’s appearance was puffy and bloated from the top of the head to the neck. The patient was immediately intubated with an orotracheal tube (6.5-mm ID). The intubation was very difficult because of major swelling of the pharyngeal mucosa narrowing the upper part of the respiratory tract. Immediately after intubation, the stridor and cyanosis disappeared, and the patient was maintained on assisted ventilation with an inspired oxygen fraction of 40%. Manual examination of the pharynx aided by direct laryngoscopy showed that the tip of the nasal catheter was under the mucosa in the posterior wall of the pharynx, just below the uvula. Chest radiograph showed subcutaneous emphysema, particularly at the level of the pectoralis muscles, with pneumomediastinum and infiltration of the right lower lobe already present in the preoperative period; there was no evidence of a pneumothorax (fig 1). Within 6 h after discontinuing nasal oxygen, the subcutaneous emphysema had almost disappeared. Extubation was performed 14 h later and was uneventful. Oral feeding was started on the fourth day after surgery, and no infection of the retropharyngeal space occurred.

Fig. 1. Postoperative chest radiograph showing subcutaneous emphysema at the level of the pectoralis muscles, the pneumomediastinum, and the infiltration of the right lower pulmonary lobe.

Fig. 1. Postoperative chest radiograph showing subcutaneous emphysema at the level of the pectoralis muscles, the pneumomediastinum, and the infiltration of the right lower pulmonary lobe.

We report an unusual cause of respiratory distress after oxygen therapy with a nasal catheter. In our case, the use of a suctioning nasotracheal catheter caused laceration of the pharyngeal mucosa and facilitated the submucosal positioning of the catheter. Administration of oxygen was responsible for the development of submucosal swelling of the pharyngeal walls; subcutaneous emphysema of the face, neck, and anterior part of the thorax; and pneumomediastinum. Acute respiratory distress followed the narrowing of the upper part of the respiratory tract caused by submucosal emphysema.

The most common cause of postoperative airway obstruction is pharyngeal obstruction from a sagging tongue in the unconscious patient. Laryngeal obstruction can also occur secondary to a laryngeal spasm or as a result of direct airway injury. 1In the present case, upper airway obstruction was associated with subcutaneous emphysema. A perforation or erosion of any part of the gastrointestinal tract may result in subcutaneous emphysema, but life-threatening upper airway obstruction is a rare complication associated with subcutaneous emphysema. Golding et al.  2described the development of acute respiratory distress associated with subcutaneous emphysema, pneumomediastinum leading to bilateral pneumothorax after laceration of the pharynx by a nasogastric tube, and subsequent administration of oxygen with a nasal catheter. Respiratory distress ensued 3 h after the end of surgery and was caused by tension pneumothoraces. Golding et al.  did not describe submucosal emphysema or stridor. Larsen 3described a similar case, but the respiratory distress was also associated with pneumothorax requiring placement of a chest tube.

Subcutaneous emphysema may be an indicator of barotrauma in patients ventilated with high inflation pressures. Once the alveolar wall has ruptured, gas dissects along the perivascular interstitial spaces to the mediastinum. From there, the gas follows the fascia planes along the trachea and esophagus into the anterior mediastinum and into the subcutaneous tissues of the neck and chest. 4As the pressure increases, the pleura may rupture and cause pneumothorax. The ventilatory conditions of our patient during surgery were unremarkable, and the subcutaneous emphysema was positively not caused by barotrauma. Pneumothorax did not occur.

Other serious complications have been described after oxygen delivery with a nasal catheter. Gastric rupture has been reported after incidental insufflation in the esophagus caused by inadvertent oxygen administration through the gastric tube 5or by inadequate positioning of the nasopharyngeal catheter. 6Pneumocephalus and exophtalmos have also been described using a nasopharyngeal catheter for oxygen administration. 7 

The nasal catheter for routine oxygen supply in the recovery period is widely used as a seemingly noninvasive manner. However, to decrease the incidence of complications associated with this route of administration, the following procedure should be carefully observed. The clinical state of the patient must justify the administration of oxygen by the nasal route. The nasal catheter must be lubricated before insertion. It is important to direct the catheter parallel to the floor of the nose. The catheter must be introduced up to a length corresponding to the distance between the base of the nose and the tragus. Administration of oxygen with a nasal catheter should be avoided when a mucosal tear is suspected either as a result of diagnostic or therapeutic procedures or traumatic lesions. In such cases, the physician should select another oxygen delivery device.

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