Magnusson J, Werner O, Carlsson C, Nordén N, Pettersson K I
Br J Anaesth. 1983 May;55(5):405-14. doi: 10.1093/bja/55.5.405.
Forty patients undergoing microlaryngoscopy were anaesthetized with thiopentone and nitrous oxide. Twenty patients received metoprolol 200 mg in a slow-release tablet once daily for 4 days up to, and including, the morning of operation, and 10 mg i.v. shortly before induction of anaesthesia. The other patients received placebo tablets and physiological saline i.v., instead. Both groups of 20 patients were further subdivided, half of the patients receiving fentanyl 1.0-1.5 mg during anaesthesia, the effect of which was antagonized by naloxone at the end of the procedure. The other patients received saline i.v. instead of fentanyl or naloxone. Metoprolol decreased heart rate and the general level of arterial pressure during anaesthesia, but did not affect the fluctuations in pressure. Arterial plasma noradrenaline concentrations during microlaryngoscopy were enhanced by metoprolol, in comparison with placebo, the reverse being the case for cortisol concentrations. Fentanyl decreased arterial pressure and plasma ACTH and cortisol concentrations regardless of whether the patient had received metoprolol. Plasma adrenaline and noradrenaline concentrations were decreased by fentanyl in the patients receiving metoprolol.
40例行显微喉镜检查的患者用硫喷妥钠和氧化亚氮麻醉。20例患者每天服用一次200毫克缓释美托洛尔片，持续4天，直至手术当天上午（包括手术当天上午），并在麻醉诱导前不久静脉注射10毫克。另外20例患者则分别服用安慰剂片和静脉注射生理盐水。每组20例患者再进一步细分，其中一半患者在麻醉期间接受1.0 - 1.5毫克芬太尼，手术结束时用纳洛酮拮抗其作用。另外一半患者静脉注射生理盐水，而非芬太尼或纳洛酮。美托洛尔可降低麻醉期间的心率和动脉压总体水平，但不影响血压波动。与安慰剂相比，美托洛尔可提高显微喉镜检查期间动脉血浆去甲肾上腺素浓度，而皮质醇浓度情况则相反。无论患者是否服用美托洛尔，芬太尼均可降低动脉压以及血浆促肾上腺皮质激素和皮质醇浓度。在服用美托洛尔的患者中，芬太尼可降低血浆肾上腺素和去甲肾上腺素浓度。
