Inhaled high dose nitric oxide is a safe and effective respiratory treatment in spontaneous breathing hospitalized patients with COVID-19 pneumonia.

BACKGROUND: Inhaled nitric oxide (NO) is a selective pulmonary vasodilator. In-vitro studies report that NO donors can inhibit replication of SARS-CoV-2. This multicenter study evaluated the feasibility and effects of high-dose inhaled NO in non-intubated spontaneously breathing patients with Coronavirus disease-2019 (COVID-19). METHODS: This is an interventional study to determine whether NO at 160 parts-per-million (ppm) inhaled for 30 min twice daily might be beneficial and safe in non-intubated COVID-19 patients. RESULTS: Twenty-nine COVID-19 patients received a total of 217 intermittent inhaled NO treatments for 30 min at 160 ppm between March and June 2020. Breathing NO acutely decreased the respiratory rate of tachypneic patients and improved oxygenation in hypoxemic patients. The maximum level of nitrogen dioxide delivered was 1.5 ppm. The maximum level of methemoglobin (MetHb) during the treatments was 4.7%. MetHb decreased in all patients 5 min after discontinuing NO administration. No adverse events during treatment, such as hypoxemia, hypotension, or acute kidney injury during hospitalization occurred. In our NO treated patients, one patient of 29 underwent intubation and mechanical ventilation, and none died. The median hospital length of stay was 6 days [interquartile range 4-8]. No discharged patients required hospital readmission nor developed COVID-19 related long-term sequelae within 28 days of follow-up. CONCLUSIONS: In spontaneous breathing patients with COVID-19, the administration of inhaled NO at 160 ppm for 30 min twice daily promptly improved the respiratory rate of tachypneic patients and systemic oxygenation of hypoxemic patients. No adverse events were observed. None of the subjects was readmitted or had long-term COVID-19 sequelae.

Rescue Treatment With High-Dose Gaseous Nitric Oxide in Spontaneously Breathing Patients With Severe Coronavirus Disease 2019.

Treatment options are limited for patients with respiratory failure due to coronavirus disease 2019. Conventional oxygen therapy and awake proning are options, but the use of high-flow nasal cannula and continuous positive airway pressure are controversial. There is an urgent need for effective rescue therapies. Our aim is to evaluate the role of inhaled nitric oxide 160 ppm as a possible rescue therapy in nonintubated coronavirus disease 2019 patients. DESIGN: Retrospective evaluation of coronavirus disease 2019 patients in respiratory distress receiving nitric oxide gas as rescue therapy. SETTING: Massachusetts General Hospital, between March 18, 2020, and May 20, 2020, during the local coronavirus disease 2019 surge. PATIENTS: Coronavirus disease 2019 patients at high risk for acute hypoxemic respiratory failure with worsening symptoms despite use of supplemental oxygen and/or awake proning. INTERVENTIONS: Patients received nitric oxide at concentrations of 160 ppm for 30 minutes twice per day via a face mask until resolution of symptoms, discharge, intubation, or the transition to comfort measures only. MEASUREMENTS AND MAIN RESULTS: Between March 18, 2020, and May 20, 2020, five patients received nitric oxide inhalation as a rescue therapy for coronavirus disease 2019 at Massachusetts General Hospital. All received at least one dosage. The three patients that received multiple treatments (ranging from five to nine) survived and were discharged home. Maximum methemoglobin concentration after 30 minutes of breathing nitric oxide was 2.0% (1.7-2.3%). Nitrogen dioxide was below 2 ppm. No changes in mean arterial pressure or heart rate were observed during or after nitric oxide treatment. Oxygenation and the respiratory rate remained stable during and after nitric oxide treatments. For two patients, inflammatory marker data were available and demonstrate a reduction or a cessation of escalation after nitric oxide treatment. CONCLUSIONS: Nitric oxide at 160 ppm may be an effective adjuvant rescue therapy for patients with coronavirus disease 2019.

High Concentrations of Nitric Oxide Inhalation Therapy in Pregnant Patients With Severe Coronavirus Disease 2019 (COVID-19).

BACKGROUND: Rescue therapies to treat or prevent progression of coronavirus disease 2019 (COVID-19) hypoxic respiratory failure in pregnant patients are lacking. METHOD: To treat pregnant patients meeting criteria for severe or critical COVID-19 with high-dose (160-200 ppm) nitric oxide by mask twice daily and report on their clinical response. EXPERIENCE: Six pregnant patients were admitted with severe or critical COVID-19 at Massachusetts General Hospital from April to June 2020 and received inhalational nitric oxide therapy. All patients tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A total of 39 treatments was administered. An improvement in cardiopulmonary function was observed after commencing nitric oxide gas, as evidenced by an increase in systemic oxygenation in each administration session among those with evidence of baseline hypoxemia and reduction of tachypnea in all patients in each session. Three patients delivered a total of four neonates during hospitalization. At 28-day follow-up, all three patients were home and their newborns were in good condition. Three of the six patients remain pregnant after hospital discharge. Five patients had two negative test results on nasopharyngeal swab for SARS-CoV-2 within 28 days from admission. CONCLUSION: Nitric oxide at 160-200 ppm is easy to use, appears to be well tolerated, and might be of benefit in pregnant patients with COVID-19 with hypoxic respiratory failure.