心肺脑复苏与脑保护的研究

Researches on Cardiopulmonary Cerebral Resuscitation and Cerebral Protection

关于心肺复苏(CPR)现已有较成熟的经验,如众所周知的ABC,即A:保持气道通畅(airway)、B:口对口人工通气(breathing)及C:闭胸心脏按压保持循环(circulation)。不过目前也存在一些争议。 新的观点认为CPR的顺序不应该是ABC,而应是首先立即恢复冠脉及脑血流,然后再进行人工通气,因为闭胸心脏按压时也能产生一定潮气量。由于大潮气量容易引起胃充气及胃内容误吸,所以现在认为人工通气时潮气量应从目前广泛接受的800-1200ml减低到500ml。 传统的闭胸心脏按压效果并不令人满意,这便促使人们寻找更有效的方法,如腹部间断加压法(IAC-CPR)、胸外按压-主动减压(ACD-CPR)及环胸挤压法(vest-CPR)。 肾上腺素是CPR中改善心输出量及血压的首选用药,目前仍主张先静注1mg,3-5分钟后可重复注射。当标准剂量无效时可适当加大剂量。 脑复苏及脑保护是复苏的难题。脑缺氧/缺血分为全脑性及局灶性。缺氧/缺血本身能造成神经元的直接损害,其中很多损害是再灌注引起的,其机理比较复杂,处理难度也很大,效果不满意。目前用轻度低温及利尿药达到降低氧耗、脱水、降低升高的颅内压效果较肯定。而针对不同发病机理的药物治疗,如应用巴比妥类药、钙通道阻滞药、氧自由基清除剂、铁螯合剂、大剂量糖皮质激素和兴奋性氨基酸抑制药等。

Patent airway, mouth - to - mouth venti-lation and closed chest compression referred to as ABC arewell accepted as three basic maneuvers of CPR. The firstpriority should be given to the restoration of circulation,with a patent airway closed chest compression moves a cer-tain amount of air in and out of the lungs and ventilationshould be established as soon as possible as a third priori-ty. A tidal volume of 800 - 1200ml has been recom-mended during mouth - to - mouth ventilation but largetidal volume induces stomach inflation and aspiration ofgastric content, so a smaller tidal volume of 500ml is ap-propriate. Although closed chest compression has been acceptedas standard technique of CPR but is inefficient so newmethods like interposed abdominal compression (IAC -CPR) and active compression - decompression (ACD -CPR) emerged. The dose of epinephrine administered during CPR hasbeen a long - time debate. So far high - dose epinephrinehas not yet been proved to improve survival rate and neuro-logic outcome, so standard dose should be started with. Cerebral resuscitation and protection are much morediffcult. The value of mild hypothermia and diuretics usedto reduce the increased intracranial pressure is well estab-lished. There are different drugs aimed at different bio-chemical events initiated by cerebral ischemia, includingbarbiturates, oxygen free radical scavengers, calciumchannel blockers etc. Being used as cerebral protectants,their clinical effectiveness remains to be confirmed.