Kirshbom P M, Skaryak L A, DiBernardo L R, Kern F H, Greeley W J, Gaynor J W, Ungerleider R M
Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA.
Circulation. 1995 Nov 1;92(9 Suppl):II490-4. doi: 10.1161/01.cir.92.9.490.
Aortopulmonary collaterals (APC) have been associated with an increased risk of choreoathetosis after deep hypothermic circulatory arrest (DHCA). To study the effects of APC on cerebral hemodynamics and metabolism before and after DHCA, a piglet model was developed.
Protocol 1: Eight 4- to 6-week-old piglets underwent placement of a left subclavian-to-main pulmonary artery shunt. Control shunts (n = 4) were ligated, APC shunts (n = 4) were left patent. All animals were placed on cardiopulmonary bypass (CPB) and cooled in identical fashion for 20 minutes. Temperature probes were placed in the nasopharynx, cortex, and deep brain. Control animals achieved significantly lower temperatures in all three areas by the end of cooling (17.5 degrees C versus 20.1 degrees C, 19.0 degrees C versus 22.3 degrees C, and 17.5 degrees C versus 21.0 degrees C, respectively, P < .005). Protocol 2: Six control and six APC animals were instrumented as described. All were placed on CPB, cooled to 18 degrees C, arrested for 90 minutes, and rewarmed to 37 degrees C. Cerebral blood flow (CBF) was measured with radioactive microspheres while warm on CPB, after cooling, and after rewarming. Arterial and sagittal sinus blood gases and CBF were used to calculate the cerebral metabolic rate of oxygen consumption (CMRO2). Both CBF and CMRO2 were significantly higher after rewarming to 37 degrees C in control versus APC animals (28 +/- 3 versus 14 +/- 2 mL/100 g per minute and 1.72 +/- 0.21 versus 1.04 +/- 0.14 mL O2/100 g per minute, respectively, P < .05).
APC decrease the rate of cerebral cooling on CPB and even if temperature is controlled result in increased cerebral metabolic derangement after DHCA. Patients with such collaterals may need additional measures to optimize cerebral protection.
主肺动脉侧支（APC）与深低温停循环（DHCA）后发生舞蹈手足徐动症的风险增加有关。为研究APC对DHCA前后脑血流动力学和代谢的影响，建立了仔猪模型。
方案1：8只4至6周龄仔猪接受左锁骨下动脉至主肺动脉分流术。对照组分流（n = 4）结扎，APC分流（n = 4）保持通畅。所有动物均行体外循环（CPB），并以相同方式冷却20分钟。将温度探头置于鼻咽、皮质和脑深部。冷却结束时，对照组动物在所有三个区域的温度显著更低（分别为17.5℃对20.1℃、19.0℃对22.3℃、17.5℃对21.0℃，P <.005）。方案2：按上述方法对6只对照动物和6只APC动物进行监测。所有动物均行CPB，冷却至18℃，停循环90分钟，然后复温至37℃。在CPB上体温正常时、冷却后及复温后，用放射性微球测量脑血流量（CBF）。用动脉血和矢状窦血气及CBF计算脑氧代谢率（CMRO2）。复温至37℃后，对照组动物的CBF和CMRO2均显著高于APC动物（分别为28±3对14±2 mL/100 g每分钟和1.72±0.21对1.04±0.14 mL O2/100 g每分钟，P <.05）。
APC降低CPB时脑冷却速率，即使温度得到控制，DHCA后也会导致脑代谢紊乱加重。有此类侧支的患者可能需要采取额外措施以优化脑保护。
