Wolfe R R, Loehr J P, Schaffer M S, Wiggins J W
University of Colorado School of Medicine, Denver.
Am J Cardiol. 1991 Jan 1;67(1):84-7. doi: 10.1016/0002-9149(91)90105-t.
Little data are available on the hemodynamic effects of premedications and anesthetic agents on infants and children. Ketamine is the most frequently used anesthetic agent for cardiac catheterization procedures in pediatric patients with congenital heart disease. Previous reports both suggest and deny ketamine's pulmonary vasoreactive effects. Since the advent of sophisticated noninvasive equipment, one of the few indications for cardiac catheterization is to obtain accurate pressure data. If ketamine alters pulmonary vascular resistance, it would negate the primary reason for the procedure. Because the patient population studied herein resides greater than or equal to 1,200 meters above sea level, concerns about pharmacologic effects on pulmonary vascular resistance are enhanced. Simultaneous pulmonary artery and aortic pressures, thermodilution cardiac outputs, and blood gases were measured in room air (16% oxygen) and with ketamine infusion in 14 patients at cardiac catheterization. Reaction to hypoxia identified 3 groups: normal, intermediate and hyperresponders. The normal responders had normal resistance ratios (0.11) in room air and had little resistance ratio response to hypoxia (+0.02), hyperoxia (-0.03) or ketamine (+0.01). The intermediate responders had a slightly higher but normal resistance ratio (0.20) in room air, and a moderate reaction to hypoxia (+0.13), hyperoxia (-0.08) and ketamine (+0.11). The hyperresponders had an elevated resistance ratio (0.42) in room air and a striking reaction to hypoxia (+0.65), hyperoxia (-0.17) and ketamine (+0.49). Hypoxia and ketamine have a greater effect on resistance ratio than hypoxia alone in patients with reactive pulmonary vascular beds. Ketamine should not be used in children undergoing procedures to establish operability based on pulmonary vascular resistance or pulmonary vascular reactivity.
关于术前用药和麻醉药物对婴幼儿血流动力学影响的数据很少。氯胺酮是先天性心脏病小儿患者心脏导管插入术最常用的麻醉剂。先前的报道既表明又否认氯胺酮有肺血管反应性作用。自从先进的非侵入性设备出现以来，心脏导管插入术的少数指征之一就是获取准确的压力数据。如果氯胺酮改变肺血管阻力，将会使该操作的主要目的无效。由于本文研究的患者群体居住在海拔大于或等于1200米的地方，因此对肺血管阻力药理作用的担忧加剧。在14例接受心脏导管插入术的患者中，于室内空气（氧气含量16%）中以及输注氯胺酮时，同时测量肺动脉和主动脉压力、热稀释心输出量及血气。对低氧的反应确定了3组：正常反应者、中度反应者和高反应者。正常反应者在室内空气中阻力比正常（0.11），对低氧（阻力比增加0.02）、高氧（阻力比降低0.03）或氯胺酮（阻力比增加0.01）的阻力比反应很小。中度反应者在室内空气中阻力比略高但仍正常（0.20），对低氧（阻力比增加0.13）、高氧（阻力比降低0.08）和氯胺酮（阻力比增加0.11）有中度反应。高反应者在室内空气中阻力比升高（0.42），对低氧（阻力比增加0.65）、高氧（阻力比降低0.17）和氯胺酮（阻力比增加0.49）有显著反应。在有反应性肺血管床的患者中，低氧和氯胺酮对阻力比的影响比单纯低氧更大。对于根据肺血管阻力或肺血管反应性来确定手术可行性的儿童，不应使用氯胺酮。
