Pneumomediastinum in COVID-19: a phenotype of severe COVID-19 pneumonitis? The results of the UK POETIC survey

Abstract

BackgroundThere is an emerging understanding that coronavirus disease 2019 (COVID-19) is associated with increased incidence of pneumomediastinum. We aimed to determine its incidence among patients hospitalised with COVID-19 in the United Kingdom and describe factors associated with outcome.MethodsA structured survey of pneumomediastinum and its incidence was conducted from September 2020 to February 2021. United Kingdom-wide participation was solicited via respiratory research networks. Identified patients had SARS-CoV-2 infection and radiologically proven pneumomediastinum. The primary outcomes were to determine incidence of pneumomediastinum in COVID-19 and to investigate risk factors associated with patient mortality.Results377 cases of pneumomediastinum in COVID-19 were identified from 58 484 inpatients with COVID-19 at 53 hospitals during the study period, giving an incidence of 0.64%. Overall 120-day mortality in COVID-19 pneumomediastinum was 195/377 (51.7%). Pneumomediastinum in COVID-19 was associated with high rates of mechanical ventilation. 172/377 patients (45.6%) were mechanically ventilated at the point of diagnosis. Mechanical ventilation was the most important predictor of mortality in COVID-19 pneumomediastinum at the time of diagnosis and thereafter (p<0.001) along with increasing age (p<0.01) and diabetes mellitus (p=0.08). Switching patients from continuous positive airways pressure support to oxygen or high flow nasal oxygen after the diagnosis of pneumomediastinum was not associated with difference in mortality.ConclusionsPneumomediastinum appears to be a marker of severe COVID-19 pneumonitis. The majority of patients in whom pneumomediastinum was identified had not been mechanically ventilated at the point of diagnosis.

Understanding Pneumomediastinum as a Complication in Patients With COVID-19: A Case Series

“… 4 , 6 While some studies have attributed this to be due to barotrauma, from either significantly higher set positive end-expiratory pressure (PEEP) or higher minute ventilation, this does not provide an explanation for the increased disposition to pneumomediastinum in those not on mechanical ventilation. 10 This case series and the study by Melhorn et al 9 present a cohort of patients with pneumomediastinum in the setting of COVID-19 in whom most patients were not mechanically ventilated; 62.2% of our cohort and 54.4% of the cohort reported by Melhorn et al were not mechanically ventilated and yet developed pneumomediastinum. This phenomenon has also been reported in case reports and small case series.…”

“…It could be argued that NIV (bilevel or continuous positive airway pressure) provides the increase in PEEP that leads to traumatic pneumomediastinum, similar to that seen in patients on mechanical ventilation who received higher PEEP prior to diagnosis of pnuemomediastinum. 4 However, 11 (47.8%) of the subjects in this nonintubated cohort and 77 in the larger study by Melhorn et al 9 did not receive positive pressure from NIV prior to diagnosis. In addition, the mean positive pressure provided in these subjects who received NIV was minimal with an average of 10.8 cm H 2 O and 7 of these subjects never received a positive pressure higher than 10 cm H 2 O.…”

“… 15 - 17 While the retrospective nature of our data and the wide minute-to-minute variations of minute ventilation witnessed at the bedside prohibited accurate recording of our subjects’ tidal volumes or minute ventilation, the number of subjects in our cohort, and in comparable studies, who developed pneumomediastinum while on NIV or HFNC are supportive of P-SILI playing a precipitating role. 9 …”

“…Furthermore, in a larger analysis of 53 hospitals in the United Kingdom, 205 patients with COVID-19 were identified who were not mechanically ventilated when pneumomediastinum was identified. 9 This suggests that while VILI may provide an explanation for pneumomediastinum in intubated non-coronavirus patients, it does not explain the occurrence in coronavirus patients, especially in nonintubated patients.…”

Pneumomediastinum in the COVID-19 era: to drain or not to drain?

“…Traumatic; Non-Traumatic, and Iatrogenic [8], [9]. The pathogenesis of air leakage into the mediastinum is thought to be due to alveolar rupture leading to air dissecting along the bronchovascular sheaths and to pulmonary interstitial emphysema that spreads into the mediastinum [5], [10], 11].…”