[Haemodynamic response to sodium nitroprusside in healthy people and in patients with left heart failure (author's...

In 10 healthy persons (group I) and in 10 patients with left heart failure the haemodynamic response to reduction of the arterial blood pressure with sodium nitroprusside (SNP) is studied. The systolic arterial pressure (SAP) is reduced in two stages first to 100 mm Hg and than to 90 mm Hg. The SAP was then allowed to reach 100 mm Hg by reduction of the SNP dose. At this SAP a constant amount of SNP and 500 ml Dextran 60 were infused. In group I the cardiac index (CI) decreases from 3,6 +/- 0,4 1/minXm2 at a SAP of 136 +/- 11 mm Hg to 3,2 +/- 0,2 1/minXm2 (p less than 0,05) at a SAP of 101 +/- 2 mm Hg. At a SAP of 89 +/- 3 mm Hg the CI is 3,0 +/- 0,3 1/minXm2 (p less than 0,05). The right atrial pressure (RAP) and the pulmonary capillary wedge pressure (PCWP) are significantly reduced (p less than 0,01). After infusion of 500 ml Dextran 60 the CI increases to 3,9 +/- 0,3 1/minXm2 (p less than 0,05). In group II at a SAP of 132 +/- 8 mm Hg the CI is 2,7 +/- 0,2 1/minXm2, at a SAP of 99 +/- 3 mm Hg the CI is 3,0 +/- 0,3 1/minxm2 (p less than 0,05) and at a SAP of 91 +/- 2 mm Hg decreases to 2,7 +/- 0,2 1/minXm2. RAP and PCWP are significantly reduced (p less than 0,01). After infusion of 500 ml Dextran 60 the CI increases to 3.3 +/- 0,2 1/minxm2 (p less than 0,05). These results show, that SNP-Infusion in patients with left heart failure can improve cardiac performance. In patients without cardiac disease the CI decreases after SNP-Infusion due to the low preload of the heart. In both groups preload restoration with Dextran 60 can increase the cardiac index.