Abstract/Text: BACKGROUND: Spontaneous pneumomediastinum (SPM) is an unusual occurrence with few cases reported. It is seen after intrathoracic pressure changes leading to alveolar rupture and dissection of air along the tracheobronchial tree. This study was undertaken to provide a thorough clinical and radiologic analysis of this patient population.
METHODS: A retrospective comparative analysis was performed on patients with SPM over 12 years. Patient demographics, clinical presentation, and radiographic and diagnostic studies were recorded. A clinical and radiologic comparison was performed with secondary pneumomediastinum.
RESULTS: Seventy-four patients were identified with a diagnosis of pneumomediastinum. A total of 28 patients with SPM were identified. The major initial complaints were chest pain (54%), shortness of breath (39%), and subcutaneous emphysema (32%). The main triggering events were emesis (36%) and asthma flare-ups (21%). No apparent triggering event was noted in 21% of patients. Chest radiograph was diagnostic in 69%; computed tomography was required in 31%. Esophagram, esophagoscopy, and bronchoscopy were performed on an individual basis and were invariably negative. When compared with secondary pneumomediastinum, SPM is more likely to be discovered by chest radiography, has a lower incidence of pneumothorax and pleural effusion, requires a shorter hospital stay, and has no associated mortality.
CONCLUSIONS: Spontaneous pneumomediastinum is a benign condition that often presents with chest pain or dyspnea. It can develop without a triggering event and with no findings on chest radiography. Treatment is expectant and recurrence is low. Secondary causes must be ruled out to avoid an unfavorable outcome.

Abstract/Text: BACKGROUND: Spontaneous pneumomediastinum (SPM) is an unusual occurrence with few cases reported. It is seen after intrathoracic pressure changes leading to alveolar rupture and dissection of air along the tracheobronchial tree. This study was undertaken to provide a thorough clinical and radiologic analysis of this patient population.
METHODS: A retrospective comparative analysis was performed on patients with SPM over 12 years. Patient demographics, clinical presentation, and radiographic and diagnostic studies were recorded. A clinical and radiologic comparison was performed with secondary pneumomediastinum.
RESULTS: Seventy-four patients were identified with a diagnosis of pneumomediastinum. A total of 28 patients with SPM were identified. The major initial complaints were chest pain (54%), shortness of breath (39%), and subcutaneous emphysema (32%). The main triggering events were emesis (36%) and asthma flare-ups (21%). No apparent triggering event was noted in 21% of patients. Chest radiograph was diagnostic in 69%; computed tomography was required in 31%. Esophagram, esophagoscopy, and bronchoscopy were performed on an individual basis and were invariably negative. When compared with secondary pneumomediastinum, SPM is more likely to be discovered by chest radiography, has a lower incidence of pneumothorax and pleural effusion, requires a shorter hospital stay, and has no associated mortality.
CONCLUSIONS: Spontaneous pneumomediastinum is a benign condition that often presents with chest pain or dyspnea. It can develop without a triggering event and with no findings on chest radiography. Treatment is expectant and recurrence is low. Secondary causes must be ruled out to avoid an unfavorable outcome.

Abstract/Text: Pneumomediastinum is an uncommon radiographic finding of potential clinical significance. Secondary pneumomediastinum (SPM) has a variety of etiologies that can lead to potentially morbid outcomes. There are limited data regarding the etiologies, diagnosis, and outcomes of this entity. A retrospective comparative study was conducted over an 11-year period of patients developing pneumomediastinum secondary to a specific pathologic or traumatic event. Forty-five patients were identified with an underlying condition resulting in SPM. Demographic data, radiologic findings, length of hospital stay, and mortality were recorded. Statistical comparison was conducted between patients with blunt thoracic trauma- and barotrauma-induced pneumomediastinum. Logistic and multiple linear regression analyses were performed to discover factors predictive of mortality and length of hospital stay. Median age of the patients was 40 years and 69% were men. Subcutaneous emphysema was identified in 44%, pneumothorax in 47%, and pleural effusion in 11%. Pneumomediastinum was identified by plain radiograph (CXR) in only 47% compared to 100% by computed tomogram (CT scan). Average length of hospital stay was 19 days and mortality was 38%. Patients with blunt thoracic trauma had a lower sensitivity for CXR to discover pneumomediastinum, were more likely to develop subcutaneous emphysema or pneumothorax, and had lower mortality and length of hospital stay compared with those with barotrauma-induced pneumomediastinum. Barotrauma was an independent predictor for hospital mortality. Secondary pneumomediastinum is a morbid condition with distinctive etiologies, radiologic findings, and outcomes. Barotrauma-induced pneumomediastinum is associated with a prolonged recovery and high mortality rate.

Abstract/Text: Background: In mechanically ventilated acute respiratory distress syndrome (ARDS) patients infected with the novel coronavirus disease (COVID-19), we frequently recognised the development of pneumomediastinum and/or subcutaneous emphysema despite employing a protective mechanical ventilation strategy. The purpose of this study was to determine if the incidence of pneumomediastinum/subcutaneous emphysema in COVID-19 patients was higher than in ARDS patients without COVID-19 and if this difference could be attributed to barotrauma or to lung frailty.
Methods: We identified both a cohort of patients with ARDS and COVID-19 (CoV-ARDS), and a cohort of patients with ARDS from other causes (noCoV-ARDS).Patients with CoV-ARDS were admitted to an intensive care unit (ICU) during the COVID-19 pandemic and had microbiologically confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. NoCoV-ARDS was identified by an ARDS diagnosis in the 5 years before the COVID-19 pandemic period.
Results: Pneumomediastinum/subcutaneous emphysema occurred in 23 out of 169 (13.6%) patients with CoV-ARDS and in three out of 163 (1.9%) patients with noCoV-ARDS (p<0.001). Mortality was 56.5% in CoV-ARDS patients with pneumomediastinum/subcutaneous emphysema and 50% in patients without pneumomediastinum (p=0.46).CoV-ARDS patients had a high incidence of pneumomediastinum/subcutaneous emphysema despite the use of low tidal volume (5.9±0.8 mL·kg-1 ideal body weight) and low airway pressure (plateau pressure 23±4 cmH2O).
Conclusions: We observed a seven-fold increase in pneumomediastinum/subcutaneous emphysema in CoV-ARDS. An increased lung frailty in CoV-ARDS could explain this finding more than barotrauma, which, according to its etymology, refers to high transpulmonary pressure.

Copyright ©ERS 2020.

Abstract/Text: Spontaneous pneumomediastinum (SPM) is a rare disorder most often affecting young males which is generally self-limiting. Despite the benign prognosis with few complications and little morbidity, it frequently confuses clinicians in primary settings, who may have difficulty differentiating SPM from other serious organ ruptures, especially oesophageal rupture (the so-called Boerhaave syndrome), which may lead to mediastinitis and may be fatal, even with appropriate interventions. An overview of adult SPM is provided, reviewing 17 studies (414 patients), including our clinical experience, and finally an algorithm for diagnosis and management of SPM is proposed, based on the characteristics of SPM.