Barotrauma Rate Is Roughly 25% in ARDS Patients Receiving ECMO

Barotrauma incidence in patients with acute respiratory distress syndrome (ARDS) receiving extracorporeal membrane oxygenation (ECMO) is 18.9% during ECMO and 7.1% after decannulation, according to study findings published in Respiratory Medicine.

Studies indicate that patients with ARDS receiving mechanical ventilation have a high risk of barotrauma, which often has poor prognosis and high mortality. Although ECMO should theoretically protect patients from barotrauma, whether it does is unclear. Investigators in China therefore sought to assess the incidence, risk factors, and epidemiology of barotrauma in patients with ARDS treated with ECMO.

The researchers conducted a retrospective analysis of 127 patients at least 15 years of age with ARDS treated with veno-venous ECMO at the China-Japan Friendship Hospital, Beijing, China, from December 2013 to December 2021. Patients with COVID-19 were excluded. Of those patients 21 had barotrauma before ECMO, 24 (18.9%) developed barotrauma during ECMO, and 9 (7.1%) patients developed barotrauma after ECMO. 

Among the 24 patients who developed barotrauma during ECMO (median age, 38 years, 37.5% women) median total ECMO run time was 29 days and median length of hospital stay was 43 days. Of these patients, 18 developed pneumothorax, 16 developed subcutaneous emphysema, 13 developed mediastinal emphysema, and 3 developed interstitial emphysema. With respect to the timing of barotrauma in relation to ARDS, the investigators found the condition developed in 6 patients within 7 days after ARDS onset; in 5 patients within 8 to 14 days of ARDS onset; in 13 patients after more than 14 days after ARDS onset (average onset, 18.7 days; median onset, 13.5 days). With respect to the timing of barotrauma in relation to the establishment of ECMO: 11 patients developed barotrauma within 7 days; 7 patients within 8 to 14 days; and 6 patients more than 14 days (average onset, 11.4 days; median onset, 8.5 days). Within this cohort, in-hospital mortality was 62.5%, and 6-month follow-up mortality was 76.2%.

Among the 9 patients who developed barotrauma after ECMO decannulation (median age, 60 years; 22.2% women), median length of hospital stay was 32.5 days. Of those patients, 5 developed pneumothorax, 4 developed subcutaneous emphysema, 4 developed mediastinal emphysema, and 2 developed interstitial emphysema. ECMO mean duration among these patients was 13.4 days. The average time to barotrauma occurrence after ECMO decannulation was 8.3 days, with 75.0% of barotrauma occurring in the late stages of ARDS (an average of 26.2 days after ARDS onset) and at least 8 days into ECMO treatment (for 54.2% of patients). In-hospital death occurred in 6 of the 9 patients.

Among the 73 patients (57.5%) who did not experience barotrauma, (median age, 54 years; 34.2% women), the median total ECMO run time was 9 days and the median length of hospital stay was 16 days. The mortality rates for these patients were 58.9% during hospitalization and 68.6% by the 6-month follow-up.

Risk factors for developing barotrauma during ECMO, identified via univariate and multivariate analyses, were elevated body temperature after establishing ECMO (odds ratio [OR], 2.997; 95% CI, 1.325-6.779; P =.008) and PJP (OR, 3.15; 95% CI, 1.070-9.271; P =.037). Investigators also identified younger age (OR, 0.953; 95% CI, 0.923-0.983; P =.003) and low platelet count after establishing ECMO (OR, 0.985; 95% CI, 0.972-0.998; P =.02) as possible risk factors. Notably, the researchers found no difference in ventilator parameters between patients with and without barotrauma.

Study limitations include unaccounted-for residual confounding and the retrospective design.

“In theory, the incidence of barotrauma should be low, but our study found a relatively high incidence in ARDS patients, 18.9% during ECMO and 7.1% after ECMO decannulation,” said study authors. “Future studies should investigate whether ultra-protective mechanical ventilation also could be feasible and effective in preventing barotrauma in high-risk patients.”