新型体外可调节肺动脉环缩装置对需肺血流约束治疗相关疾病血流动力学影响的实验研究

Complex congenital heart diseases seriously endanger lives of babies diagnosed as severe pulmonary hypertension, high-pressure univentriclular heart and transposition of the great artery with intact ventricle septal defect which requires training of left ventricle. Classical pulmonary artery banding is hard to adjust pulmonary blood flow precisely which leads to a high postoperative mortality mostly because of the difficulties in balancing the pulmonary blood flow after operations, that is, either over or less restricted pulmonary blood flow may equally extend hospital stays or fail in preventing the progress of pulmonary hypertension, or even losing the opportunity of second operation. Current remote-control banding devices in vitro experienced by foreign labs are expensive and complicatedly designed, among which be structured by rigid plane seriously affecting normal pulmonary blood flow and cause hemodynamic changes. Medical grade Luer joints and fingers of rubber gloves are used as materials by certain domestic banding devices proved nondurable. Our research is to develop a superior implantable pulmonary blood control device which can be easily adjusted in vitro or removed when necessary and is certainly low-cost. The advantages of it lies in the flexible "C" shape design with saccule catheter as the inner wall, into which injecting fluid is to adjust the pulmonary blood flow monitored by ultrasound. After partially immobilized such device by fixing it to the root of pulmonary without affecting the aorta by Dacron patch, one may easily locate it by X-ray because of its iron structure. You only have to pull out the guide wire to quickly release the fluid injected before when emergency. Operators simply bury the catheter beneath the skin of patients requiring long term ventricle training to avoid the risks of infection. Generally speaking, such design fits the national conditions through its simpleness, cheapness and mostly reliability. Animal experiments contribute in study of postoperative hemodynamic effects after banding by observing the pathologic changes. It would be helpful to improve the current design and would further decrease mortality and clinical expense and increase the assurance of second operations.

合并重度肺动脉高压复杂畸形、高压型单心室及需左室训练的完全大动脉转位等严重危及婴幼儿生命。全麻下开胸肺动脉环缩术因患儿与生活状态差异大难以精确调节，即使术中满意也易导致术后肺血流过多或过少，肺血流限制过多显著增加围术期死亡率和监护室住院时间，限制不够则不能阻止肺动脉高压进展或丧失二次手术矫正机会。国外实验体外遥控肺动脉环缩装置可于拔管后清醒下调节肺动脉限制程度，但成本高、结构复杂。本研究提出一种新型植入式体外可调节肺血流限制装置，术中可方便安装于肺动脉根部，待患儿平稳度过围术期，清醒状态超声监测指导调节肺动脉环缩程度，球囊外接导管可埋置皮下，根据随诊反复调节肺血流，并可于二次手术时去除。本研究将装置初步用于动物实验，研究对围术期血流动力学影响及肺血流调节精准性，观察肺动脉环缩后的病理改变及可能存在的左右肺动脉牵拉等以完善设计，临床应用将降低此类患儿死亡率、住院费用及显著提高二次手术成功率。

合并重度肺动脉高压的复杂畸形、高压型单心室及需要左室训练的完全大动脉转位等复杂先心病严重危及婴幼儿的生命。全麻开胸下肺动脉环缩术是目前常用的术士，但因患儿与生活状态差异大难以精确调节，即使术中调节满意，也容易导致术后肺血流过多或者过少，肺血流限制过多显著增加围术期死亡率和监护室住院时间，限制不够则不能够阻止肺高压的进展或丧失二次手术矫正的机会。国外目前新研制了体外遥控调节肺动脉环缩装置，用于拔管后清醒状态下肺动脉的环缩，可随时调节，但成本高、结构复杂，本研究提出的一种新型可调节环缩装置可在术中安装在肺动脉根部，不做任何调整，待术后平稳度过围术期，清醒状态下，在超声检测下，通过向导管内注射生理盐水，逐渐环缩肺动脉，调整完成后可将导管一端埋入皮下，在二次手术时取出。在本次课题研究中，将装置初步用于动物实验，研究其对围术期实验动物血流动力学的影响及肺动脉血流调节的精准性，观察肺动脉环缩后的病理生理改变。在实验中证实，该装置可有效地收缩肺动脉，在超声检测跨装置压差30-50mmHg时环缩效果稳定，不容易产生弹性疲劳或漏水。在目标压差大于60mmHg时，需要缓慢注水，防止血流动力学波过大波动，如果出现氧供氧需严重失衡，需要松开部分环缩，但不能全部松开，防止短时间肺血过多造成肺水肿。在合理的压差控制下，该装置可保持2个月以上压差不变，这对肺动脉环缩术来说是有重要的意义，既可以达到目标环缩强度，有可以随时调节环缩程度，对于II期手术的储备非常重要。在高压组中发现，压力差越高，环缩装置的压差越不稳定，可能与动物烦躁血流变化有关，也可能与本装置的材料不具备太大的延展性有关，不能随着动脉的运动产生细微变化，因此材料的升级可能是下一步装置研究的改进项目之一。另外在实验过程中发现整个环缩装置的环形部分会对主动脉产生挤压，虽然环缩过程中不会向主动脉侧突出，但为了进一步较少附加影响，下一步还要改进装置的外形设计。