Background: Hypoxic patients with Covid 19 pneumonia are at high risk of adverse outcomes . Inhaled Nitric Oxide (iNO) inhibits viral entry and replication of SARS-CoV2 and in vivo proof of its antiviral actions is unavailable to date . This feasibility study was conducted to test the antiviral effects of iNO and to describe clinical outcomes .
Methods: The phase II open label, randomised controlled feasibility trial (ISRCTN 16806663) conducted at a South Indian tertiary care referral centre, recruited COVID-19 pneumonia patients with hypoxic respiratory failure and allocated them into iNO cases and control groups (1:1). iNO was administered as pulses for 30 minutes for three consecutive days at 12-hour intervals in cases, in addition to standard of care received by the control group . The primary outcome was decline in viral load, as defined by a surrogate change in the RT-PCR cycle threshold . The co-primary clinical outcome was time to improvement of> 2 points on the WHO Ordinal Scale (WOS).
Results: Among the 29 patients enrolled , 14 iNO cases and 11 controls completed the study protocol . Longitudinal analysis revealed a significant difference in the decline (p <0.002, N= 23) in viral load among the iNO cases compared to controls . The proportion of patients achieving 2-point improvement in the WOS within 14 days of randomisation was significantly higher in the iNO cases (n=11 , 79 %), as compared to the controls (n=4 , 36 %) (p=0.05).
Conclusions: Our study demonstrated significant improvement in virological and clinical outcomes among patients with adjunct iNO therapy and no adverse effects were reported.