Inhaled nitric oxide as a salvage therapy in patients with severe ARDS

Abstract

IntroductionInhaled nitric oxide (iNO) has been shown to preferentially dilate pulmonary vasculature within well ventilated regions of lung without causing systemic hypotension. Patients with severe ARDS may develop marked ventilation perfusion mismatch, severe hypoxemia, pulmonary hypertension, and right heart failure. Use of iNO may help mitigate these pathologic changes. So we used iNO to assess it as a salvage therapy in patients with severe ARDS. MethodsWe describe 4 cases of pneumonia with severe ARDS with right heart failure in which iNO was used as salvage therapy to improve right heart failure and oxygenation when they did not respond to conventional measures. iNO was delivered in inspiratory limb of ventilator circuit by NOxBOX mobile system. Dose of iNO was titrated between 5 and10 ppm. In each of these patients, we monitored hemodynamic status (pulse rate, intra-arterial blood pressure, vasopressor requirements), central venous pressure (CVP), serum lactate, methemoglobin (MetHb) levels, arterial blood gases (ABG) and PaO2/FiO2 (p/f) ratios every 6 h till first 24 h and then every 12 h till 24 h of stopping iNO. 2D Echo was done by a trained cardiologist before initiation of iNO and then every 24 h till 24 h of stopping NO and pulmonary artery systolic pressure (PASP) recorded. ResultsiNO was used for duration ranging from 30 to 120 h. In all patients hemodynamics, oxygenation and PASP showed improvement that persisted even after 24 h of discontinuing iNO. None of the 4 patients had methemoglobinemia or other serious side effects. ConclusioniNO may be used as a salvage therapy for refractory hypoxemia and right heart failure in severe ARDS.