Effects of Pinacidil, Tetrathylammonium and Glibenclamide on Hypoxic Vasoconstriction in Isolated Perfused Rabbit Lungs / 대한마취과학회지

BACKGROUND: This study investigated the effects of the K+ channel opener, pinacidil on hypoxic pulmonary vasoconstriction in isolated perfused rabbit lungs. In order to evaluate the vasodilatation mechanism of K+ channel opener, we also studied the effects of two K+ channel blocker, tetraethylammonium (TEA), a Ca2+ activated K+ channel blocker and glibenclamide (GLB), an ATP-sensitive K+ channel blocker. METHODS: Isolated lungs from white rabbits were ventilated with a normoxic gas (21%O2-5%CO2-74%N2) and a hypoxic gas (3%O2- 5%CO2-92%N2) alternatively, and then perfused with blood-containing perfusate solution. After a hypoxic pressor response (HPR) had been obtained, various drugs were added to the perfusate reservoir to achieve the predetermined circulating concentration, and the influences of the drugs on HPR were then tested. RESULTS: Pinacidil (0.3-6.0 mcM) produced a dose-dependent pulmonary vasodilation on hypoxic ventilation challenge. TEA (1 mM) caused pulmonary vasoconstriction in normoxic ventilation and potentiated a hypoxic pressor response. When the hypoxic pressor response was potentiated by TEA, pinacidil (1.0, 3.0 mcM) reduced the contraction, but GLB did not cause pulmonary vasoconstriction under normoxic ventilation, potentiate a hypoxic pressor response. CONCLUSIONS: Piacidil is capable of opposing the pulmonary responses of acute hypoxia. Moreover the effects of TEA and GLB suggest that HPV might be mediated through Ca2+ activated K+ channels, not through ATP-sensitive K+ channels.

A Comparison of the Transoesophageal Doppler and Thermodilution Techniques for Cardiac Output Measurement in Off-Pump Coronary Artery Bypass Surgery Patients / 대한마취과학회지

BACKGROUND: The aim of this study was to compare the accuracy of measured cardiac output using the newly developed esophageal doppler device with that of the thermodilution method using a pulmonary artery catheter. METHODS: In 15 patients undergoing off-pump coronary artery bypass surgery, cardiac outputs were measured at four episodes of surgery; (1) after induction of anesthesia, (2) during dissection of the internal mammary artery, (3) during anastomosis of the left anterior descending artery, and (4) after closure of the pericardium. RESULTS: The bias between the two methods was 0.52 +/- 1.09 L/min. Analysis of the changes in cardiac output from sample episode 1 to 2, from sample episode 2 to 3 and from sample episode 3 to 4, expressed as percent change values, shows no significant differences between the two methods (P > 0.05). CONCLUSIONS: The esophageal doppler accurately reflects changes in cardiac output with time when compared with that of the thermodilution.