THE RELEASE OF NITROGLYCERIN ABSORBED INTO THE CENTRAL VENOUS CATHETER

This study mas conducted to evaluate the release of nitroglycerin (NG) that has been absorbed into the central venous catheter. A 0.05% NG s olution was infused through a central venous catheter and the flow rat es were set at 1, 5, or 10 ml/h, given over 12, 24, or 18 h. The cathe ter,vas hushed with lactate Ringer solution after completion of the NG infusion, The elution of the lactate Ringer solution from the tip of the catheter was then collected and assayed for its NG concentration b y high performance liquid chromatography (HPLC), A higher concentratio n of NG was released with a faster flow rate and a longer infusion, Th e high level of NG release continued during the first 20 min, and rang ed from a minimum of 0.07 mg/ml to a maximum that exceeded 0.15 mg/ml, Subsequently, the NG concentration gradually declined, but low concen trations of 0.006-0.02 mg/ml were still maintained 360 min later. Thus , it is suggested that if a catheter such as the Swan-Ganz continues t o be used after the completion of a NG infusion, certain pharmacologic al effects due to the absorption of NG into the catheter body should b e expected for at least 60 min.