Rosenthal M, Bush A, Deanfield J, Redington A
Department of Paediatric Respiratory Medicine, Royal Brompton National Heart and Lung Hospital, London, U.K.
Circulation. 1995 Jan 15;91(2):372-8. doi: 10.1161/01.cir.91.2.372.
There are several potential physiological differences between the atriopulmonary (AP) and the total cavopulmonary connection (TCPC) Fontan circulations. Studies suggest that the TCPC reduces energy loss due to turbulence and may have more dependence on respiratory movement for pulmonary blood flow. We compared cardiopulmonary physiology during rest and exercise in patients who had undergone the AP Fontan procedure with those who had undergone the TCPC Fontan procedure.
Forty-three children were studied more than 6 months after undergoing a Fontan procedure (23 AP and 20 TCPC); 106 healthy children were also studied as a control group. Measurements of effective pulmonary blood flow, stroke volume, arteriovenous oxygen difference, minute ventilation, heart rate, and oxygen and carbon dioxide consumption were made with an Innovision quadrupole mass spectrometer. Data from the control group allowed calculation of z scores for the Fontan groups matched for age, sex, pubertal stage, and body surface area. Maximal exercise performance was equal in the two Fontan groups, but it was below normal. However, adaptation to exercise was different in the Fontan groups. After 9 minutes of exercise, pulmonary blood flow rose less in the AP group than in the TCPC group (P < .01), and the stroke volume in the AP group also tended to be lower (P = .057) and their arteriovenous oxygen difference was significantly greater (P < .01). Although minute ventilation per unit of carbon dioxide production was similar in the Fontan groups at this level of exercise, children in the TCPC group breathed faster by approximately 10 breaths per minute (P < .005).
At submaximal exercise, children who had undergone the TCPC Fontan procedure had pulmonary hemodynamics superior to those of children who had undergone the AP procedure, largely because of respiratory adaptation that permitted blood to be "sucked" into the lungs. To achieve the same maximal exercise performance, children who had undergone the AP procedure had a superior metabolic adaptation to exercise stress.
心房肺（AP）和全腔静脉肺动脉连接（TCPC）Fontan循环之间存在一些潜在的生理差异。研究表明，TCPC减少了因湍流导致的能量损失，并且可能对呼吸运动在肺血流方面有更多依赖。我们比较了接受AP Fontan手术的患者与接受TCPC Fontan手术的患者在静息和运动时的心肺生理情况。
对43名接受Fontan手术6个月以上的儿童进行了研究（23例AP和20例TCPC）；还研究了106名健康儿童作为对照组。使用Innovision四极质谱仪测量有效肺血流量、每搏量、动静脉氧分压差、分钟通气量、心率以及氧和二氧化碳消耗量。根据对照组数据计算出与Fontan组年龄、性别、青春期阶段和体表面积相匹配的z分数。两个Fontan组的最大运动能力相当，但均低于正常水平。然而，Fontan组对运动的适应性不同。运动9分钟后，AP组的肺血流量升高幅度低于TCPC组（P < 0.01），AP组的每搏量也趋于更低（P = 0.057），且其动静脉氧分压差显著更大（P < 0.01）。尽管在该运动水平下，Fontan组每单位二氧化碳产生的分钟通气量相似，但TCPC组儿童的呼吸频率快约每分钟10次（P < 0.005）。
在次最大运动时，接受TCPC Fontan手术的儿童的肺血流动力学优于接受AP手术的儿童，这主要是因为呼吸适应性使得血液能够“吸入”肺部。为了达到相同的最大运动能力，接受AP手术的儿童对运动应激具有更好的代谢适应性。
