右美托咪啶镇静对小儿心血管系统的影响

背景右美托咪啶（dexmedetomidine，DEX）可影响成年人的心率（heartrate，HR）、平均动脉压、心脏指数（cardiacindex，CI）、心搏指数（strokeindex，SI）和体循环血管阻力指数（systemicvascularresistanceindex，SVRI）。本研究旨在探讨DEX镇静对小儿心血管系统是否存在类似作用。方法给予DEX后使用影像学方法监测小儿血流动力学的变化。第一组（DEX．短时）8例患者接受DEX2μg/kg于10分钟内输注完毕且手术在10分钟内完成；第二组（DEX．长时）9例患者在首次给药（DEX2μg／kg）的基础上按需追加DEX1μg／（kg·h），手术时间超过10分钟。使用无创心排血量探头监测CI、SI、SVRI。用重复测量的方差分析比较10分钟、20分钟和出室（Aldrete评分达9）3个时间点血流动力学与基础数值的差异，数据以均数表示（可信区间95％）。结果DEX-短时组共8例，DEX．长时组共9例。在DEX-短时组，T1点的HR和C1分别降低了18．9（2．3～35．5）次／分和0．74（0．15—1．33）L／（min·m2），其余无显著变化，所有指标在R，点都恢复到基础值。在DEX．长时组，HR、CI降低持续至恢复期[分别降低了24．0（8．3—39．6）次／分、1．51（0．95～2．06）L／（min·m2）]；同时，恢复期的SI降低8．0l（1．71-14．31）ml／m2，而SVRI升高[776．0（271．9—1280．4）dyn-s／（cm5·m2）]。两组的平均动脉压均未见显著变化。结论DEX使小儿Cl降低，且有累积效应。对于接受长时间手术的患者，胍、CI持续降低到患者出室，同时伴随SI降低、SVRI升高。

BACKGROUND： Dexmedetomidine （DEX） affects heart rate （HR）, mean arterial blood pressure, cardiac index （CI）, stroke index （SI）, and systemic vascular resistance index （SVRI） in adults. In this study we sought to determine whether similar effects occur in children undergoing DEX sedation. METHODS： Hemodynamic changes in children were followed during IV DE）（ sedation for radiological procedures. One group of 8 patients （DE,X-brief） received a bolus （2 mcg/kg bolus over 10 minutes） and completed the procedure within 10 minutes. The second group of 9 patients （DEX-prolong） received the bolus plus additional DEX as needed to maintain sedation for procedures lasting longer than 10 minutes （additional 1 mcg/kg/hr infusion with second bolus if needed）. CI, SI, and SVRI were measured using a continuous noninvasive cardiac output monitor. Changes in hemodynamic variables at minutes 10, 20, and discharge （time at which patient achieved Aldrete Score 9） were compared to baseline by repeated measures ANOVA with effect sizes reported as mean [ 95 % confidence interval]. RESULTS： Data were obtained during 8 D EX-brief and 9 DEX-prolong procedures. In DEX-brief, HR and CI decreased （18.9 -2.3 to 35.5 ] bpm and 0.74 [0. 15 to 1.33 ] L/min/ m2; respectively） at T1. There was no change in any other hemodynamic variables and all hemodynamic variables returned to baseline at recovery. In DEX-prolong, both HR and CI remained decreased （24.0 [8.3 to 39.6] bpm, 1.51 [0.95 to 2.06] L/min/m2 ; respectively） at recovery. In addition, SI was decreased （8.01 [ 1.71 to 14.31 ] mL/m2） and SVRI was increased （776.0 [271.9 to 1280, 4] dynes-sec/cm5/m2） at recovery in the DEX-prolong group. There were no significant changes in mean arterial blood pressure in either group. CONCLUSIONS： DEX decreases CI in children and has a cumulative effect. For patients undergoing prolonged procedures HR and CI remained decreased at the time of discharge together with a decrease in SI and an increase in SVRI.