[Clinical studies of isosorbide dinitrate spray in postoperative patients]

We investigated the effect of isosorbide dinitrate (ISDN) single spray, containing 1.25 mg of ISDN, on cardiovascular and respiratory functions in eight postoperative patients. Concentrations of plasma ISDN and its metabolites were also investigated. Hemodynamic as well as blood gas studies were performed at 4 points (before, plus 10, 30 and 60 minutes after administration of ISDN) and the blood levels of ISDN and its metabolites were measured at 5 points (before, plus 5, 10, 30 and 60 minutes after administration of ISDN). Mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), cardiac index (CI), pulmonary capillary wedge pressure (PCWP) and central venous pressure (CVP) decreased significantly and heart rate (HR) increased significantly at 10 and 30 minutes after the spray. The maximum changes observed of each parameters were MAP 7%, MPAP 22%, CI 9%, PCWP 33%, CVP 36% and HR 6%. Systemic and pulmonary vascular resistance indices did not change significantly throughout the study. PaO2 decreased significantly only at 10 minutes after the spray. Plasma ISDN concentration showed the maximum value of 56.3 ng.ml-1 at 5 minutes after the spray. After this value, the concentrations decreased rapidly. From this study, we conclude that single spray of ISDN is effective in decreasing preload promptly, but it is not effective in decreasing afterload. When using the spray, we should pay attention to pulmonary oxygenation.