- 學位論文
體外循環中人工血管端對邊縫合於周邊動脈時夾角之探討-以體外模型對右鎖骨下動脈之灌注為例-
The Research of Included Angle on Artificial Vascular Graft End-to-Side Sutured to Peripheral Artery for Extracorporeal Circulation - In Vitro Model for Right Subclavian Artery Perfusion
摘要
利用人工血管以端對邊的方式，縫合於右鎖骨下動脈或右腋動脈，當作體外循環中動脈含氧血灌注的連接管，已成為現今在主動脈手術以及其他難以在升主動脈插管的心臟手術之重要方法。由其進行主動脈弓部手術時，從人工血管經由右鎖骨下動脈至右總頸動脈及右椎動脈的含氧血灌注，再經由威利氏循環的交通，可提供符合生理的腦部保護。而透過人工血管對右鎖骨下動脈灌注時，究竟對頭部及右上肢血流量如何的重新分配，一直是外科醫師及體外循環師所關心的。本實驗選取健康人的電腦斷層影像，利用逆向工程技術，重建一個主動脈弓部及其分支的假體，透過體外流體力學的實驗法，模擬使用8 mm直徑的人工血管，縫合於右鎖骨下動脈，以不同的夾角 (共計有15°，30°，45°，60°，75°與90°，6種夾角) 來進行體外實驗的灌流；並應用先前公開文獻中正常人血管血流量的參考值，作為提供組織足夠的灌流依據，以求得一個血流分配較佳的灌注夾角。實驗的結果顯示，透過人工血管對全身的灌注模式中 (Bi-Ac模式)，當夾角30° 時，是維持正常人體組織灌流較為理想的灌注夾角；而在僅針對頭部與上臂的灌注模式中 (Bi-ADEFc模式)，夾角30° 的血流灌注，亦是當主動脈弓部手術時，對於頭部組織保護較為理想的夾角。而在灌注夾角大於60° 時，不論何種灌流模式，對於頭部都有明顯灌注不足的現象，同時也會造成右上肢的過度灌流。此夾角確立後，除了對主動脈手術中的體外循環，能有預先的準備及良好的灌注外；對於其他像小傷口、再次手術及升主動脈鈣化的心臟血管手術而言，可達到體外循環中良好的組織保護，並降低手術的併發症。
並列摘要
By using an end-to-side vascular graft sutured to the right subclavian artery or right axillary artery as an arterial oxygenated blood perfusion conduit has become an alternative way of cardiopulmonary bypass setup, especially for aortic surgery and for surgery that cannot establish arterial access at the ascending aorta. During aortic arch surgery, physiological brain protection can be achieved by selective brain perfusion (with circle of Willis) via sending the oxygenated blood through the vascular graft to the right subclavian artery then to the right common carotid artery and right vertebral artery. However, the fraction of blood flow distribution to the brain and upper limb in this graft-subclavian perfusion has always been concern to the cardiovascular surgeons and perfusionists. In this study, by using reverse engineering to reconstruct a mock of aortic arch model based a health adult computer tomography image. Through in vitro study of hydrodynamic fluid test, the fractions of blood flow distribution under different included angle (15°, 30°, 45°, 60°, 75° and 90°, six included angles) between vascular graft (8 mm diameter) and right subclavian artery were calculated. Combining with previous publicized reference values of normal blood flow from physiological human vessels, we expect to obtain the ultimate included angle for suitable blood flow distribution and pressure for organ perfusion. As a result, perfusion to whole body mode (Bi-Ac mode), an angle of 30° is the most suitable included angle to maintain physiological tissue perfusion; and selected perfusion to head and upper limbs mode (Bi-ADEFc mode), an angle of 30° is also the most suitable included angle for brain protection. If the included angle is greater than 60°, hypo-perfusion of head and hyper-perfusion of right upper limb would occur. Once this ultimate included angle is established, it not only can be applied to aortic surgery, but also can be used in minimally invasive cardiac surgery, re-do cardiac operation and surgeries with severe calcified ascending aorta, with the result of this study, increasing safety of the cardiopulmonary bypass in terms of tissue protection and reducing operational complications can be achieved.