Intubation and mechanical ventilation avoided by using almitrine bismesylate in an acute hypoxemic pneumonia

Use of almitrine in spontaneously breathing patients with COVID-19 treated with high-flow nasal cannula oxygen therapy and with persistent hypoxemia

BACKGROUND

Almitrine, a selective pulmonary vasoconstrictor in hypoxic area, improves oxygenation in mechanically ventilated patients with COVID-19 but its effects in spontaneously breathing patients with COVID-19 remain to be determined.

METHODS

We prospectively studied the effects of almitrine (16 µg/kg/min over 30 min followed by continuous administration in responders only) in 62 patients (66% of male, 63 [53-69] years old) with COVID-19 treated with high-flow nasal cannula oxygen therapy (HFNO) and with persistent hypoxemia, defined as a PaO₂/FiO₂ ratio < 100 with FiO₂ > 80% after a single awake prone positioning session. Patients with an increase in PaO₂/FiO₂ ratio > 20% were considered as responders.

RESULTS

Overall, almitrine increased the PaO₂/FiO₂ ratio by 50% (p < 0.01), decreased the partial arterial pressure of carbon dioxide by 7% (p = 0.01) whereas the respiratory rate remained unchanged and 46 (74%) patients were responders. No patient experienced right ventricular dysfunction or acute cor pulmonale. The proportion of responders was similar regardless of the CT-Scan radiological pattern: 71% for the pattern with predominant ground-glass opacities and 76% for the pattern with predominant consolidations (p = 0.65). Responders had lower intubation rate (33 vs. 88%, p < 0.01), higher ventilator-free days at 28-day (28 [20-28 ] vs. 19 [2-24] days, p < 0.01) and shorter ICU length of stay (5 [3-10] vs.12 [7-30] days, p < 0.01) than non-responders.

CONCLUSIONS

Almitrine could be an interesting therapy in spontaneously breathing patients with COVID-19 treated with HFNO and with persistent hypoxemia, given its effects on oxygenation without serious adverse effects regardless of the CT-Scan pattern, and potentially on intubation rate. These preliminary results need to be confirmed by further randomized studies.

Effect of intravenous almitrine on intubation or mortality in patients with COVID-19 acute hypoxemic respiratory failure: A multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Severe hypoxemia in patients with COVID-19 pneumonia might result from hypoxic pulmonary vasoconstriction, contributing to ventilation/perfusion (V/Q) mismatch. Because almitrine improves V/Q, it might reduce the risk for mechanical ventilation (MV) in such patients. Our primary objective was to determine the effect of almitrine on the need for MV at day 7.

METHODS

In a randomised double-blind placebo-controlled trial involving 15 ICUs, patients hospitalized for COVID-19 pneumonia and experiencing acute hypoxemic respiratory failure were randomly assigned to receive 5 days of intravenous low-dose (2 µg.kg^-1.min^-1) almitrine or placebo. The primary outcome was endotracheal intubation for MV or death within 7 days after randomisation. Secondary outcomes included in-hospital mortality, 28-day mortality, number of ventilator-free days, number of days in the ICU and the hospital, and treatment discontinuation for pre-specified adverse effects. This trial was registered with ClinicalTrials.gov, NCT04357457.

FINDINGS

Between September 3, 2020 and September 25, 2021 181 patients were enrolled and randomly assigned to almitrine (n=89) or placebo (n=92). 179 patients (excluding two who withdrew from the study) were included in the intention-to-treat analysis (mean age: 60·1 years; 34% women) and analyzed. On day 7, the primary endpoint occurred in 32 patients assigned to almitrine (36%) and in 37 patients assigned to placebo (41%), for a difference of -4·3% (95% confidence interval: -18·7% to 10·2%). Secondary outcomes (28-day mortality, in-hospital mortality, ventilator-free days at day 28, days in the ICU and the hospital, and treatment discontinuation for pre-specified adverse effects) did not differ between the two groups.

INTERPRETATION

In patients with COVID-19 acute hypoxemic respiratory failure, low-dose almitrine failed in reducing the need for MV or death at day 7.

FUNDING

Programme Hospitalier de Recherche Clinique (PHRC COVID 2020) funded by the French Ministry of Health, Les Laboratoires Servier (Suresnes, France) providing the study drug free of charge.

Chemo- and ergoreflexes in health, disease and ageing

The chemo- and ergoreflexes (muscle receptors) are among the major reflex arches, which adapt the respiratory and the cardiovascular system to the needs of the body and contribute to its homeostasis. The present paper reviews the interplay of these reflexes with other major cardiovascular reflex arches; the methods used for their calculation and their normal range data. The clinical implications of chemoreflex sensitivities and ergoreflexes in chronic heart failure (CHF) as well as the application of chemoreflexes in coronary artery disease, sudden cardiac death and multiple organ dysfunction syndrome are discussed.