Letter to the Editor: "Use of inhaled epoprostenol with high flow nasal oxygen in non-intubated patients with severe COVID-19".

PURPOSE: Acute lung injury associated with COVID-19 contributes significantly to its morbidity and mortality. Though invasive mechanical ventilation is sometimes necessary, the use of high flow nasal oxygen may avoid the need for mechanical ventilation in some patients. For patients approaching the limits of high flow nasal oxygen support, addition of inhaled pulmonary vasodilators is becoming more common but little is known about its effects. This is the first descriptive study of a cohort of patients receiving inhaled epoprostenol with high flow nasal oxygen for COVID-19. MATERIALS AND METHODS: We collected clinical data from the first fifty patients to receive inhaled epoprostenol while on high flow nasal oxygen at our institution. We compared the characteristics of patients who did and did not respond to epoprostenol addition. RESULTS: The 18 patients that did not stabilize or improve following initiation of inhaled epoprostenol had similar rates of invasive mechanical ventilation as those who improved or stabilized (50% vs 56%). Rates of mortality were not significantly different between the two groups (17% and 31%). CONCLUSIONS: In patients with COVID-19 induced hypoxemic respiratory failure, the use of inhaled epoprostenol with high flow nasal oxygen is feasible, but physiologic signs of response were not related to clinical outcomes.

Evaluation of Continuous Inhaled Epoprostenol in the Treatment of Acute Respiratory Distress Syndrome, Including Patients With SARS-CoV-2 Infection.

BACKGROUND: Acute respiratory distress syndrome (ARDS) management is primarily supportive. Pulmonary vasodilators, such as inhaled epoprostenol (iEPO), have been shown to improve PaO2:FiO2 (PF) and are used as adjunctive therapy. OBJECTIVE: To identify the positive response rate and variables associated with response to iEPO in adults with ARDS. A positive response to iEPO was defined as a 10% improvement in PF within 6 hours. METHODS: This retrospective study included adults with ARDS treated with iEPO. The primary endpoint was the variables associated with a positive response to iEPO. Secondary endpoints were positive response rate and the change in PF and SpO2:FiO2 within 6 hours. Statistical analysis included multivariable regression. RESULTS: Three hundred thirty-one patients were included. As baseline PF increased, the odds of responding to iEPO decreased (odds ratio [OR], 0.752, 95% CI, 0.69-0.819, p < 0.001). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related ARDS (OR 0.478, 95% CI, 0.281-0.814, p = 0.007) was associated with decreased odds of a positive response to iEPO. The total population had a 68.3% positive response rate to iEPO. SARS-CoV-2-related ARDS and non-SARS-CoV-2-related ARDS had a 59.5% and 72.7% positive response rate, respectively. iEPO significantly improved PF (71 vs 95, P < 0.001) in the whole population. CONCLUSION AND RELEVANCE: iEPO was associated with a positive effect in a majority of moderate-to-severe ARDS patients, including patients with SARS-CoV-2-related ARDS. Lower baseline PF and non-SARS-CoV-2-related ARDS were significantly associated with a positive response to iEPO. The ability to predict which patients will respond to iEPO can facilitate better utilization.

High-Dose Nitric Oxide From Pressurized Cylinders and Nitric Oxide Produced by an Electric Generator From Air.

BACKGROUND: High-dose (≥ 80 ppm) inhaled nitric oxide (INO) has antimicrobial effects. We designed a trial to test the preventive effects of high-dose NO on coronavirus disease 2019 (COVID-19) in health care providers working with patients with COVID-19. The study was interrupted prematurely due to the introduction of COVID-19 vaccines for health care professionals. We thereby present data on safety and feasibility of breathing 160 ppm NO using 2 different NO sources, namely pressurized nitrogen/NO cylinders (INO) and electric NO (eNO) generators. METHODS: NO gas was inhaled at 160 ppm in air for 15 min twice daily, before and after each work shift, over 14 d by health care providers (NCT04312243). During NO administration, vital signs were continuously monitored. Safety was assessed by measuring transcutaneous methemoglobinemia (SpMet) and the inhaled nitrogen dioxide (NO2) concentration. RESULTS: Twelve healthy health care professionals received a collective total of 185 administrations of high-dose NO (160 ppm) for 15 min twice daily. One-hundred and seventy-one doses were delivered by INO and 14 doses by eNO. During NO administration, SpMet increased similarly in both groups (P = .82). Methemoglobin decreased in all subjects at 5 min after discontinuing NO administration. Inhaled NO2 concentrations remained between 0.70 ppm (0.63-0.79) and 0.75 ppm (0.67-0.83) in the INO group and between 0.74 ppm (0.68-0.78) and 0.88 ppm (0.70-0.93) in the eNO group. During NO administration, peripheral oxygen saturation and heart rate did not change. No adverse events occurred. CONCLUSIONS: This pilot study testing high-dose INO (160 ppm) for 15 min twice daily using eNO seems feasible and similarly safe when compared with INO.

COVID-19 Acute Respiratory Distress Syndrome and Pulmonary Embolism: A Case Report of Nebulized Nitroglycerin and Systemic Thrombolysis For Right Ventricular Failure.

BACKGROUND: Acute respiratory compromise caused by complications of COVID-19, such as acute respiratory distress syndrome (ARDS) or thromboembolic disease, is a complex syndrome with unique challenges in treatment. Management often requires time and intensive care through a multiprofessional, multispecialty approach. Initial management is particularly challenging within the limited-resource environment of the emergency department (ED). The emergency physician's toolbox of treatments with reasonably rapid onset remains limited to respiratory support, prone positioning, steroids, and anticoagulation. CASE REPORT: We present a case of a patient with COVID-19 complicated by ARDS and bilateral pulmonary emboli with severe right ventricular dysfunction and systemic hypotension treated with nebulized nitroglycerin and systemic thrombolytic therapy in the ED. Serial evaluation of right ventricular function using point of care ultrasound over the next 2 h showed improvement of function with both agents as well as improvement in the patient's respiratory rate and work of breathing. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case describes a novel use of a widely available medication for patients with COVID-19-induced right ventricular dysfunction. Nebulized nitroglycerin may be an option to improve right ventricular function when other inhaled pulmonary vasodilators are not available in the initial ED setting. © 2021 Elsevier Inc.

Evaluation of the Efficacy and Safety of Inhaled Epoprostenol and Inhaled Nitric Oxide for Refractory Hypoxemia in Patients With Coronavirus Disease 2019.

OBJECTIVES: The objectives of this study were to evaluate the efficacy and safety of inhaled epoprostenol and inhaled nitric oxide in patients with refractory hypoxemia secondary to coronavirus disease 2019. DESIGN: Retrospective single-center study. SETTING: ICUs at a large academic medical center in the United States. PATIENTS: Thirty-eight adult critically ill patients with coronavirus disease 2019 and refractory hypoxemia treated with either inhaled epoprostenol or inhaled nitric oxide for at least 1 hour between March 1, 2020, and June 30, 2020. INTERVENTIONS: Electronic chart review. MEASUREMENTS AND MAIN RESULTS: Of 93 patients screened, 38 were included in the analysis, with mild (4, 10.5%), moderate (24, 63.2%), or severe (10, 26.3%), with acute respiratory distress syndrome. All patients were initiated on inhaled epoprostenol as the initial pulmonary vasodilator and the median time from intubation to initiation was 137 hours (68-228 h). The median change in Pao2/Fio2 was 0 (-12.8 to 31.6) immediately following administration of inhaled epoprostenol. Sixteen patients were classified as responders (increase Pao2/Fio2 > 10%) to inhaled epoprostenol, with a median increase in Pao2/Fio2 of 34.1 (24.3-53.9). The mean change in Pao2 and Spo2 was -0.55 ± 41.8 and -0.6 ± 4.7, respectively. Eleven patients transitioned to inhaled nitric oxide with a median change of 11 (3.6-24.8) in Pao2/Fio2. A logistic regression analysis did not identify any differences in outcomes or characteristics between the responders and the nonresponders. Minimal adverse events were seen in patients who received either inhaled epoprostenol or inhaled nitric oxide. CONCLUSIONS: We found that the initiation of inhaled epoprostenol and inhaled nitric oxide in patients with refractory hypoxemia secondary to coronavirus disease 2019, on average, did not produce significant increases in oxygenation metrics. However, a group of patients had significant improvement with inhaled epoprostenol and inhaled nitric oxide. Administration of inhaled epoprostenol or inhaled nitric oxide may be considered in patients with severe respiratory failure secondary to coronavirus disease 2019.