Sear John W, Higham Helen
Nuffield Department of Anaesthetics, University of Oxford, John Radcliffe Hospital, Headington, Oxford, England.
Drugs Aging. 2002;19(6):429-51. doi: 10.2165/00002512-200219060-00003.
The elderly patient may show normal physiological changes of the cardiovascular and respiratory systems that accompany aging, as well as features of intrinsic cardiac disease. The latter include: a past history of myocardial infarction or ischaemic heart disease; history of congestive cardiac failure; angina; arterial hypertension (BP >140/90mm Hg); and conduction disorders. A key aspect to the safe and effective anaesthetic management of the elderly patient with cardiac disease is a careful preoperative assessment and optimisation of pre-existing drug therapies. All cardiac medications should be continued up to and including the morning of surgery with the exception of anticoagulation involving warfarin, and perhaps large doses of angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists in patients with hypertension or heart failure. Anaesthetic techniques used in these patients should avoid episodes of excessive hypotension after induction of anaesthesia or large blood loss, or the combination of hypertension and tachycardia after noxious stimulation. The latter physiological disturbances are pivotal for the development of myocardial ischaemia. Both premedication (if used) and anaesthesia should avoid excessive sedation and respiratory depression. The choice of anaesthetic technique may vary between: a balanced technique involving an opiate and a volatile agent; an intravenous technique utilising infusions of propofol; or regional anaesthesia with or without additional sedation. There are no good data to suggest any one technique is better than the rest. The occurrence of ischaemia in the perioperative period may precede the postoperative development of significant cardiac morbidity and mortality (including myocardial infarction or unstable angina, congestive cardiac failure, cerebrovascular accidents, and severe arrhythmias). A number of strategies have been examined to reduce these adverse outcomes. The effect of acute beta-adrenoceptor blockade in treatment-naive patients is associated with reduction in the haemodynamic response to noxious stimuli and decreased ECG evidence of myocardial ischaemia, as well as a reduction in the number of cardiac adverse events. Other drugs (calcium channel antagonists, alpha(2)-agonists and adenosine modulators) have a less predictable influence on both myocardial ischaemia and hard cardiac outcomes. There is inadequate evidence at present to define the optimal time course for acute beta-blockade, or the groups of patients in whom preoperative beta-blockade should be initiated in the absence of contraindications. Nevertheless, addition of beta-blockers to the preoperative regimen should be considered in patients with evidence of or at risk for coronary disease undergoing major surgery. There is also evidence that long-term beta-adrenoceptor or calcium channel blockade or nitrate therapy for the high-risk cardiac patient offers little protection against silent myocardial ischaemia, nonfatal infarction, cardiac failure and cardiac death.
老年患者可能会出现伴随衰老的心血管和呼吸系统的正常生理变化,以及内在心脏病的特征。后者包括:心肌梗死或缺血性心脏病病史;充血性心力衰竭病史;心绞痛;动脉高血压(血压>140/90mmHg);以及传导障碍。对患有心脏病的老年患者进行安全有效的麻醉管理的一个关键方面是仔细的术前评估和对现有药物治疗的优化。所有心脏药物应持续使用直至手术当天上午,包括手术当天上午,但涉及华法林的抗凝治疗除外,对于高血压或心力衰竭患者,大剂量的血管紧张素转换酶抑制剂和血管紧张素II受体拮抗剂可能也除外。这些患者使用的麻醉技术应避免麻醉诱导后出现过度低血压或大量失血,或避免有害刺激后出现高血压和心动过速的情况。后一种生理紊乱是心肌缺血发生的关键因素。术前用药(如果使用)和麻醉都应避免过度镇静和呼吸抑制。麻醉技术的选择可能有所不同,包括:一种涉及阿片类药物和挥发性麻醉剂的平衡技术;一种使用丙泊酚输注的静脉技术;或有或没有额外镇静的区域麻醉。没有充分的数据表明哪种技术比其他技术更好。围手术期缺血的发生可能先于术后发生严重的心脏发病率和死亡率(包括心肌梗死或不稳定型心绞痛、充血性心力衰竭、脑血管意外和严重心律失常)。已经研究了许多策略来减少这些不良后果。在未接受过治疗的患者中,急性β肾上腺素能受体阻滞剂的作用与减少对有害刺激的血流动力学反应、减少心肌缺血的心电图证据以及减少心脏不良事件的数量有关。其他药物(钙通道拮抗剂、α2激动剂和腺苷调节剂)对心肌缺血和严重心脏结局的影响较难预测。目前没有足够的证据来确定急性β受体阻滞剂的最佳用药时间,也没有足够的证据来确定在没有禁忌证的情况下应在哪些患者群体中开始术前β受体阻滞剂治疗。然而,对于接受大手术的有冠心病证据或有冠心病风险的患者,应考虑在术前治疗方案中加用β受体阻滞剂。也有证据表明,对高危心脏病患者进行长期β肾上腺素能受体或钙通道阻滞或硝酸盐治疗对无症状心肌缺血、非致命性梗死、心力衰竭和心源性死亡几乎没有保护作用。