ADDITIVE EFFECT ON GAS-EXCHANGE OF INHALED NITRIC-OXIDE AND INTRAVENOUS ALMITRINE BISMESYLATE IN THE ADULT-RESPIRATORY-DISTRESS-SYNDROME

Objective: To assess the additive effect of inhaled nitric oxide (NO) and intravenous almitrine bismesylate (ALM) on gas exchange. Design: P rospective self-controlled study. Setting: 3 medico-surgical intensive care units. Patients: 17 patients with severe hypoxemia (PaO2/FIO2 ra tio: 88 +/- 30 mmHg, venous admixture: 47 +/- 7 %) and elevated mean p ulmonary artery pressure (MPAP: 30 +/- 5 mmHg) due to adult respirator y distress syndrome (ARDS). Interventions: 5 conditions were studied: 1) baseline, 2) 5 to 10 ppm of NO during 30 min, 3) discontinuation of NO during 30 min, 4) ALM infusion (0.5 mg/kg) during 30 min, 5) ALM i nfusion (0.5 mg/kg) during 30 min in combination with 5 to 10 ppm of N O. Measurement and results: The PaO2/FIO2 ratio rose from 88 +/- 30 to 98 +/0 37 mmHg (NS) with NO alone, and from 92 +/- 25 to 130 +/- 56 m mHg (P < 0.01) with NO + ALM (p < 0.05 vs NO alone). Seven patients we re considered as ''NO-responders'' (rise in PaO2/FIO2 ratio of 10 mmHg or more with NO); in this subgroup the PaO2/FIO2 ratio rose from 87 /- 30 to 128 +/- 39 mmHg (P < 0.05) with NO alone, and from 93 +/- 20 to 169 +/- 51 mmHg (p < 0.01) with NO + ALM (p < 0.05 versus NO alone) . MPAP decreased from 30 +/- 5 to 26 +/- 5 mmHg (p < 0.01) with NO alo ne, increased slightly from 28 +/- 5 to 31 +/- 5 mmHg (NS) with ALM al one and decreased to 27 +/- 5 mmHg (p < 0.05) with NO + ALM. Conclusio ns: NO + ALM had additive effects on gas exchange while decreasing MPA P in patients with ARDS. The effects of NO alone were small and non si gnificant, except in a subgroup of 7 patients in whom the combination of both therapies had the more pronounced results.