LAUSR

BACKGROUND Almitrine, a drug enhancing hypoxic pulmonary vasoconstriction, has been proposed as a rescue therapy for refractory hypoxemia in Covid related Acute Respiratory Distress Syndrome (C-ARDS). We aimed at investigating the response to almitrine depending on the cause of ARDS (Covid vs Non Covid). METHODS Monocenter retrospective study from 2014 to 2021. All patients diagnosed with moderate to severe ARDS and treated with almitrine as rescue therapy for refractory hypoxemia were studied. Factor independently associated with oxygenation response to almitrine infusion were determined. RESULTS 60 patients with ARDS and treated with almitrine were analyzed, 36 (60%) due to SARS-CoV2 infection and 24 (40%) due to other causes. Baseline PaO2/FiO2 was 78 [61-101] mmHg, 76% had at least one prone positioning before the start of almitrine infusion. Median PaO2/FiO2 increased by +38 [7-142] mmHg (+61% [10-151]) after almitrine infusion. PaO2/FiO2 increased by +134 [12-186] mmHg in non-Covid ARDS (NC-ARDS) and by +19 [8-87] mmHg in C-ARDS. The increase in PaO2/FiO2 was lower in C-ARDS than in NC-ARDS (p=0.013). In multivariable analysis, C-ARDS, non-invasive ventilation and concomitant use of norepinephrine were independently associated with a decreased oxygenation response to almitrine infusion. CONCLUSIONS Our study reports a highly variable response to almitrine infusion in ARDS patients with refractory hypoxemia. Independent factors associated with a reduced oxygenation response to almitrine infusion were: Covid ARDS, concomitant use of norepinephrine, and non-invasive ventilatory strategy.