A case of subcutaneous emphysema/mediastinal emphysema during the use of humidified high-flow nasal cannula

Abstract

Background: Heated, humidified, high-flow nasal cannula (HHFNC) oxygen therapy allows optimal humidification of inspired gas at high flows and creates a distending pressure similar to nasal continuous positive airway pressure [1]. It has been safely used in adults with moderate hypoxemia with few complications [2, 3]. Hereby, we report serious complications occurred during HHFNC oxygen therapy. Case presentation: A 53-year-old female with hemophagocytic lymphohistiocytosis (HLH) was admitted to the intensive care unit because of respiratory failure. After weaning from mechanical ventilation which lasted for 2 weeks, HHFNC therapy at 40 L/min with an FiO2 of 0.5 was started for hypoxemia. Four days later, dyspnea and hypoxemia occurred and chest X-ray and CT scan revealed localized pneumothorax, subcutaneous emphysema, and massive pneumomediastinum. After cessation of HHFNC, respiratory condition improved. Conclusion: Subcutaneous emphysema, pneumothorax, and pneumomediastinum should be notified as a serious complication during HHFNC therapy.

A case report of pneumomediastinum in a COVID‐19 patient treated with high‐flow nasal cannula and review of the literature: Is this a “spontaneous” complication?

“…As a form of oxygen support, HFNC is considered to be safe and gentler than mechanical ventilation when used in adults with moderate hypoxemia, 61,62 and Vianello et al 63 tested HFNC in patients with severe hypoxemic acute respiratory failure consequent to SARS‐CoV‐2 infection, suggesting its safety for less severe patients. However, they were rarely reported, pneumothorax and pneumomediastinum are possible complications of HFNC even in non–COVID‐19 patients 64‐66 …”

“…However, they were rarely reported, pneumothorax and pneumomediastinum are possible complications of HFNC even in non-COVID-19 patients. [64][65][66] An increased gradient of pressure in the alveoli compared with the lung interstitium was described as a possible mechanism by Makclin et al 67 Following rupture of the alveolar membrane, air penetrates into the interstitium, first causing interstitial emphysema, subsequently reaching the pulmonary hilum, and eventually provoking pneumomediastinum. 68 This can happen when the intra-alveolar pressure increases or when the pressure in the interstitium decreases.…”

Pneumomediastinum in a patient with COVID-19 due to diffuse alveolar damage

“…In this patient, the origin of the pneumomediastinum is seen as a result of acute respiratory distress syndrome. 6 A few cases of pneumomediastinum in patients with COVID-19 have been reported. The probable mechanism in these patients was diffuse alveolar damage leading to cyst formation and subsequent rupture.…”

Conservative management of subcutaneous emphysema and pneumomediastinum in a COVID-19 viral pneumonia patient-case report

“…In tracheal injury due to instrumentation, mediastinal emphysema, pneumothorax, dyspnea, dysphonia, cough, hemoptysis and pneumoperitoneum can occur. 9 Subcutaneous emphysema can be diagnosed by chest xray but some cases of pneumomediastinum can be missed without a lateral film. CT scan is the definitive diagnostic tool.…”