[Hemodynamics and serum nitroglycerin concentration during intraoperative use of nitroglycerin patches]

We investigated the effect of number of nitroglycerin (TNG) as patches, containing 5 mg of TNG per sheet, on hemodynamics in 29 adult patients undergoing elective surgery. Patients were randomly allocated to four groups according to the number of the sheets applied (0, 2, 5 and 10 sheets). Hemodynamics as well as plasma TNG concentration were measured at 4 points (just before and 30, 60 or 120 minutes after application of TNG patch) in each group (n > or = 6). Plasma TNG concentrations depended on the number of the sheets and increased until 120 min after the application. Mean arterial pressure decreased gradually and significantly after applying two sheets or more. However, no relation was observed between the plasma concentration of TNG and the decrease in mean arterial pressure. We conclude that induced hypotension can not be intensified by increasing the number of the sheets of TNG patch.