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ニトログリセリン(TNG)低血圧麻酔にジルチアゼム(DZ)を併用した場合の心血管系に及ぼす効果を,エンフルラン麻酔下の17名の婦人科手術患者を対象に検討した。収縮期血圧は,TNG単独投与のA群では目標とする90mmHgに到達するのに15分以上を要したが,DZを2μg/kg/min (B群),5μg/kg/min (C群)で併用すると5分後に目標値となり,中止後の復圧も容易であった。C群の心拍数は投与60分でA群に比較し有意に低値となり,中止15分後も低下した。中心静脈圧,肺動脈圧,肺動脈楔入圧は3群とも有意に低下したが,心拍出量はC群で低血圧開始前に比べ有意に減少した。収縮期血圧を90mmHg前後に維持させるTNGの投与量は,DZの併用により量依存性に減少した。DZを2μg/kg/minで同時投与すれば,調節性に優れ心血管系を抑制することなくTNGの投与量を節減できる。

Hemodynamic effects of nicardipine-induced hypotension during enflurane/nitrous oxide were evaluated in 10 surgical patients. An infusion of nicardipine was titrated to maintain mean arterial pressure at 60 to 70 mmHg under enflurane 1.5 to 2.0 vol% and nitrous oxide 60 vol%. Mean arterial pressure was well controlled with the nicardipine infusion, whereas cardiac index increased with decreased systemic vascular resistance. Heart rate increased concomitantly with decreased blood pressure, which indicated that enflurane 1.5 to 2.0 vol% did not suppress baroreceptor reflex during nicardipine administration. However, rate-pressure-product was not increased by the nicardipine. Right and left ventricular systolic work indices were not increased by the nicardipine. Right ventricular ejection fraction was not also changed by the nicardipine. Although serum norepinephrine level increased during the nicardipine infusion, the values remained within physiological ranges. Our results suggest that nicardipine-induced hypotension may be safely performed during enflurane/nitrous oxide anesthesia because neither ventricular work nor myocardial oxygen demand was increased by nicardipine.