From the Journals

Inhaled vasodilator type has no impact on outcomes



Inhaled vasodilators with nitric oxide and epoprostenol yielded similar patient outcomes, based on data from more than 11,000 patients.

Mechanically ventilated patients with severe acute respiratory failure may be treated with inhaled vasodilators using nitric oxide or epoprostenol to improve oxygenation, but data on practice patterns and head-to-head comparisons of effectiveness for the two options are limited, wrote Nicholas A. Bosch, MD, of Boston University, and colleagues.

In a study published in the journal Chest, the researchers used the Premier Healthcare Database to emulate a cluster randomized trial. The study population included 11,200 patients aged 18 years and older who were hospitalized at one of 303 hospitals with acute respiratory failure or acute respiratory distress between 2016 and 2020.

The patients received either nitric oxide (iNO) or epoprostenol (iEpo) during a hospital stay. A total of 6,366 patients received iNO first, 4,720 received iEpo first, and 114 received both on the same day. The median age of the patients was 58 years, and 64.6% of patients received neuromuscular blockades on the day they began vasodilator therapy. The primary outcome for effectiveness was successful extubation within 28 days of receiving a vasodilator. The outcomes for evaluating practice patterns included the choice of first inhaled vasodilator, days of invasive mechanical ventilation before starting a vasodilator, duration of use, proportion of patients who switched between iNO and iEpo, and the proportion who received each type of vasodilator.

A total of 104 hospitals (34.3%) used iNO exclusively, and 118 hospitals (38.9%) used iEpo exclusively. No differences in successful extubation rates appeared between these iNO and iEpo groups (37.0% vs. 34.7%; hazard ratio, 0.97). In addition, no differences were observed between the iNO and iEpo hospitals in total hospital costs or patient deaths or discharge to hospice, and the results persisted in a multivariate analysis.

Overall, the results were similar in a subgroup analysis, although patients receiving iNO were more likely to have successful extubation after controlling for organ dysfunction, the researchers noted.

“Our study provides stronger and more robust evidence that there are no differences in patient outcomes based on inhaled vasodilator type,” and suggest that either type may be used for patients whom clinicians think would benefit, the researchers wrote in their discussion. However, neither vasodilator type has been shown to significantly improve mortality, they noted.

The findings were limited by several factors including the observational design, lack of data on medication dose, and the use of nonrandom samples of hospitalizations and patients with laboratory and vital signs data, the researchers noted. The study also did not identify the specific indication for inhaled vasodilator therapy, and did not adjust for other therapies such as prone positioning or adherence to lung protective ventilation, they said.

However, the results were strengthened by the large sample size and more precise estimates of effectiveness than previous smaller studies, and suggest similar outcomes for patients and costs for hospitals, they concluded.

The study was funded by the National Institutes of Health National Center for Advancing Translational Sciences. Lead author Dr. Bosch also was supported by NIH/NCATS, the National Heart, Lung, and Blood Institute, and the Department of Defense. The researchers had no financial conflicts to disclose.

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