High or low doses of almitrine bismesylate in ARDS patients responding to inhaled NO and receiving norepinephrine?

Objective: To evaluate the effects on oxygenation and pulmonary haemodynamics of almitrine bismesylate (AB) 5 microg/kg per minute and 16 microg/kg per minute in ARDS patients responding to and receiving inhaled NO (iNO) and presenting septic shock requiring norepinephrine, while no difference was observed in a previous trial including iNO responders and nonresponders.

Design: Prospective, cohort study.

Setting: Adult medico-surgical intensive care unit of a university hospital.

Patients: Fifteen patients with ARDS receiving and responding to iNO (10 ppm) and presenting septic shock requiring norepinephrine (mean 0.5+/-0.45 microg/kg per minute, range 0.08- 2.08).

Interventions: The protocol consisted of two consecutive phases in a fixed order: continuous intravenous infusion of AB 5 microg/kg per minute for 30 min, and continuous intravenous infusion of AB 16 microg/kg per minute for 30 min.

Measurements And Main Results: AB 5 microg/kg per minute significantly increased PaO2/FiO2 ( P<0.05) compared with iNO alone [160 (range 77-450) mmHg vs 122 (range 70-225) mmHg]. AB 16 microg/kg per minute produced a greater increase of PaO2/FiO2 ( P<0.05) when compared with 5 microg/kg per minute [227 (range 84-501) mmHg]. AB did not improve shunt at any dose regimen. AB produced an increase in mean pulmonary arterial pressure (MPAP) from 22+/-5 to 25+/-4 mmHg ( P<0.03). MPAP did not significantly increase between the two doses. Pulmonary vascular resistances and other haemodynamic and respiratory parameters were not affected by almitrine bismesylate.

Conclusions: These results suggest that it is possible to obtain a further improvement in oxygenation by increasing AB infusion rate in ARDS patients iNO responders receiving norepinephrine. Due to the potential deleterious effects of AB, this strategy should be used in the most severely hypoxaemic patients.