Tranquilli W J, Thurmon J C, Benson G J
Am J Vet Res. 1986 Oct;47(10):2134-7.
The arrhythmogenic dose of epinephrine (ADE) was determined in 6 pigs during steady-state anesthesia (1.5% halothane in O2) and steady-state anesthesia plus xylazine (1.1 mg X kg-1 X hr-1; IV infusion) and after either prazosin (alpha 1) or metoprolol (beta 1) adrenergic blockade during halothane-xylazine (H-X) anesthesia. A constant infusion (1, 2, 3, 5, and 10 micrograms X kg-1 X min-1) of freshly mixed epinephrine (100 micrograms X ml-1 in saline solution) was used to determine ADE. The ADE was defined as the total dose of epinephrine which produced 4 or more continuous or intermittent, premature, ventricular contractions within a 15-s period. The mean epinephrine total dose values during 1.5% halothane anesthesia, H-X anesthesia alone, or H-X anesthesia after either prazosin (0.1 mg X kg-1) or metoprolol (0.5 mg X kg-1) adrenergic blockade were 3.60 +/- 0.844, 2.68 +/- 0.402, 11.85 +/- 3.804, and 5.17 +/- 0.587 micrograms X kg-1, respectively. Xylazine administration did not significantly decrease ADE, although mean arterial pressure significantly increased. Prazosin administration significantly increased ADE and was associated with an increased heart rate and a decreased mean arterial pressure. We conclude that alpha 1-blockade with prazosin is more protective to epinephrine-induced arrhythmias in H-X-anesthetized pigs than is beta 1-blockade with metoprolol.
在6头猪处于稳态麻醉（氧气中1.5%氟烷）、稳态麻醉加赛拉嗪（1.1毫克/千克/小时；静脉输注）以及在氟烷 - 赛拉嗪（H - X）麻醉期间使用哌唑嗪（α1）或美托洛尔（β1）进行肾上腺素能阻滞之后，测定了肾上腺素的致心律失常剂量（ADE）。使用新鲜混合的肾上腺素（盐溶液中100微克/毫升）以恒定输注速率（1、2、3、5和10微克/千克/分钟）来测定ADE。ADE被定义为在15秒内产生4次或更多次连续或间歇的室性早搏的肾上腺素总剂量。在1.5%氟烷麻醉、单独的H - X麻醉或在使用哌唑嗪（0.1毫克/千克）或美托洛尔（0.5毫克/千克）进行肾上腺素能阻滞后的H - X麻醉期间，肾上腺素的平均总剂量值分别为3.60±0.844、2.68±0.402、11.85±3.804和5.17±0.587微克/千克。尽管平均动脉压显著升高，但赛拉嗪的使用并未显著降低ADE。哌唑嗪的使用显著增加了ADE，并伴有心率增加和平均动脉压降低。我们得出结论，在H - X麻醉的猪中，与使用美托洛尔进行β1阻滞相比，使用哌唑嗪进行α1阻滞对肾上腺素诱导的心律失常更具保护作用。
