Pneumomediastinum in COVID-19 disease: Outcomes and relation to the Macklin effect

Abstract

Aim Pneumomediastinum (PM) is associated with several etiologies and mechanisms. Although it has been described more than 100 years ago, the literature is limited to small retrospective studies. This study aimed to follow patients with coronavirus disease (COVID-19) that developed PM during hospitalization and describe their clinical and radiological evolution. Methods A prospective cohort was developed with patients with PM, excluding those with aerodigestive trauma, inside a hospital COVID-19 dedicated hospital. Clinical variables including onset of symptoms, hemodynamic instability, associated complications, the need of interventions, and disease course were all recorded. Also, radiological findings such as the presence of the Macklin effect, extension of lung involvement by COVID-19, and characteristics of the PM were analyzed. Results Twenty-one patients with non-traumatic PM were followed, resulting in an overall incidence of 0.5% during the study period. Seven (33%) patients had associated pneumothorax and malignant/tension PM was observed in three (14%) cases. The Macklin effect could be found in 11 patients (52%) and the majority of them had more than 50% of lung involvement due to COVID-19. The mortality rate was 49%; however, no deaths were directly related to the PM. Conclusions PM incidence is probably increased in the severe acute respiratory syndrome caused by COVID-19, especially in those with greater involvement of the lungs, and the Macklin effect may be an important underlying mechanism of this complication. Usually, PM has a benign course, but complications like tension/malignant PM may occur requiring prompt detection and intervention.

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

“…The mean age of the cohort (59.1 years) is consistent with inpatient international COVID-19 PTM cohorts from Brazil, Romania, Turkey, Pakistan and the USA [ 13 , 16 – 19 ]. It is somewhat younger than the mean age of general COVID-19 inpatients in the UK, according to the largest epidemiological study (70.4 years) [ 20 ].…”

“…Pneumothorax was found to co-exist with PTM in 40.3% of cases. This compares to reported rates of between 20.0% and 72.7% in other series with more than 10 patients [ 6 , 13 , 16 – 18 , 22 ]. There was no finding of an effect on mortality of pneumothorax within this cohort, nor specifically for those patients who were mechanically ventilated when pneumothorax occurred.…”

COVID-19 ARDS: a review of imaging features and overview of mechanical ventilation and its complications

“…Pneumomediastinum has been identified as the most common barotrauma-related event in patients with mechanical ventilation for COVID-19 ARDS [ 26 ]. Pneumomediastinum occurs secondary to alveolar rupture with backtracking of air through the interstitium in the peribronchial and perivascular sheaths into the hilum and eventually into the mediastinum, a phenomenon which has been described as Macklin effect [ 27 , 29 , 30 ]. Pneumomediastinum can be identified on chest x-ray by radiolucent air surrounding the normal anatomic structures within the mediastinum.…”

Air leak syndromes (Pneumomediastinum, pneumothorax, and subcutaneous emphysema) in Critically ill COVID – 19 patients – Prevalence, risk factors, and outcome.

“…12 The Macklin effect has been observed in COVID-19 patients and could explain the high incidence of spontaneous pneumo-mediastinum often leading to pneumothorax. 13,14,25,26 We studied D-dimer, CRP and Ferritin at admission to assess the role of in ammation. Admission D-dimer in ALS group was observed to be higher and reached statistical signi cance.…”