@article {Adnot69, author = {S Adnot and P Radermacher and P Andrivet and JL Dubois-Rande and A Dupeyrat and F Lemaire}, title = {Effects of sodium-nitroprusside and urapidil on gas exchange and ventilation-perfusion relationships in patients with congestive heart failure}, volume = {4}, number = {1}, pages = {69--75}, year = {1991}, doi = {10.1183/09031936.93.04010069}, publisher = {European Respiratory Society}, abstract = {Vasodilators usually decrease arterial PO2 in patients with congestive heart failure (CHF) because of alteration in ventilation-perfusion (Va/Q) relationships. The effects of sodium nitroprusside (SNP) and urapidil (U), a new selective alpha 1-receptor antagonist, were investigated in seven patients with CHF. The distribution of ventilation and perfusion was examined using the multiple gas elimination technique. The haemodynamic responses to SNP and U were similar, cardiac index increasing by 25\% with SNP and by 31\% with U. Despite a similar increase of mixed venous oxygen tension, the arterial PO2 decreased from 11.3 +/- 0.8 to 9.6 +/- 0.6 kPa (p less than 0.01) with SNP but remained unchanged (11.0 +/- 0.9 vs 11.4 +/- 0.8 kPa, NS) with U. SNP and U both increased perfusion to lung units with Va/Q ratios of 0.1 or less with no change in shunt fraction. The fractional perfusion to total low Va/Q ratios (low Va/Q + shunt) was higher with SNP than with U (14.1 +/- 2.6 vs 9.5 +/- 2.3\%, p less than 0.01). The results suggest that gas exchange and Va/Q relationships are altered less with U than with SNP in patients with CHF.}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/4/1/69}, eprint = {https://erj.ersjournals.com/content/4/1/69.full.pdf}, journal = {European Respiratory Journal} }