Kirkham F J
Institute of Child Health (UCL), The Wolfson Centre, Mecklenburgh Square, London WC1N 2AP, UK.
Pediatr Cardiol. 1998 Jul-Aug;19(4):331-45. doi: 10.1007/s002469900318.
Because of advances in surgical and cardiopulmonary bypass techniques it is now possible to definitively repair the vast majority of congenital heart disease in infancy or childhood. Although the majority of survivors do not have obvious cerebral sequelae, there is increasing disquiet about the high incidence of acute neurological events in the immediated postoperative period as well as evidence that at long-term follow-up there are subtle cognitive and motor deficits in many. Some children are more at risk of neurodevelopmental problems, either because of their cardiac (e.g. , extensive aortopulmonary collaterals) or cerebrovascular (e.g., the propensity to large vessel dissection) anatomy or because of genetic predisposition (e.g., to prothrombotic disorders). The incidence may vary with the surgery (e.g., the Fontan operation) and the cardiopulmonary bypass technique necessary to achieve an adequate technical repair (e.g., low or no flow at deep hypothermia). Recognition of the population at risk will lead to prevention of serious sequelae. Data collected in adults may be misleading, and many pediatric units have developed their own practice, but recent studies in animal models of child surgery and in children have produced some evidence to guide management to ensure the optimal cerebral as well as cardiac outcome. Pump flow should be maintained at least 30 ml/kg/min where possible, with inotropic support to maintain blood pressure if necessary. If pump flow must be lowered or circulatory arrest is essential, thorough cerebral cooling to deep hypothermic temperatures is mandatory; a pH-stat strategy may make this easier, but an alpha-stat strategy may be better in those operations that can be performed at moderate hypothermia. There is no evidence that the available pulsatile pumps offer an advantage. Tissue oxygenation may reach critical levels and a high hematocrit and oxygen tension may reduce the risk of significant hypoxia. There is a risk of embolization in children, which can be reduced with membrane oxygenators and careful monitoring; the role of arterial filtration remains controversial. The only protective agent that can currently be recommended is methylprednisolone to protect the spinal cord (e.g., in operations on the aortic arch). Further studies are needed in this important area.
由于外科手术和体外循环技术的进步，现在有可能在婴儿期或儿童期对绝大多数先天性心脏病进行确定性修复。虽然大多数幸存者没有明显的脑部后遗症，但人们对术后即刻急性神经事件的高发生率越来越担忧，同时也有证据表明，在长期随访中，许多人存在细微的认知和运动缺陷。一些儿童更容易出现神经发育问题，这可能是由于他们的心脏（例如广泛的主肺动脉侧支）或脑血管（例如大血管夹层的倾向）解剖结构，或者是由于遗传易感性（例如血栓形成倾向）。发病率可能因手术（例如Fontan手术）和实现充分技术修复所需的体外循环技术（例如深低温下低流量或无流量）而异。识别高危人群将有助于预防严重后遗症。在成人中收集的数据可能会产生误导，许多儿科单位都有自己的做法，但最近在儿童手术动物模型和儿童中的研究已经产生了一些证据，以指导管理，确保获得最佳的脑部和心脏结果。只要有可能，泵流量应维持在至少30毫升/千克/分钟，必要时使用血管活性药物支持以维持血压。如果必须降低泵流量或必须进行循环停止，则必须将脑部彻底冷却至深低温；pH稳态策略可能会使这更容易，但在可以在中度低温下进行的手术中，α稳态策略可能更好。没有证据表明现有的搏动泵具有优势。组织氧合可能达到临界水平，高血细胞比容和氧张力可能降低严重缺氧的风险。儿童存在栓塞风险，使用膜式氧合器并仔细监测可降低这种风险；动脉滤器的作用仍存在争议。目前唯一可以推荐的保护剂是甲基强的松龙，用于保护脊髓（例如在主动脉弓手术中）。在这个重要领域还需要进一步研究。
