Background: Vasoplegic syndrome (VPS) is defined as systemic hypotension due to profound vasodilatation and loss of systemic vascular resistance (SVR), despite normal or increased cardiac index, and characterized by inadequate response to standard doses of vasopressors, and increased morbidity and mortality. It occurs in 9%–44% of cardiac surgery patients after cardiopulmonary bypass (CPB). The underlying pathophysiology following CPB consists of resistance to vasopressors (inactivation of Ca²⁺ voltage gated channels) on the one hand and excessive activation of vasodilators (SIRS, iNOS, and low AVP) on the other. Use of angiotensin-converting enzyme inhibitor (ACE-I), calcium channel blockers, amiodarone, heparin, low cardiac reserve (EF < 35%), symptomatic congestive heart failure, and diabetes mellitus are the perioperative risk factors for VPS after cardiac surgery in adults. Till date, there is no consensus about the outcome-oriented therapeutic management of VPS. Vasopressors such as norepinephrine (NE; 0.025–0.2 µg/kg/min) and vasopressin (0.06 U/min or 6 U/h median dose) are the first choice for the treatment. The adjuvant therapy (hydrocortisone, calcium, vitamin C, and thiamine) and rescue therapy (methylene blue [MB] and hydroxocobalamin) are also considered when perfusion goals (meanarterial pressure [MAP] > 60–70 mmHg) are not achieved with nor-epinephrine and/or vasopressin.

中文翻译：

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心血管手术后血管麻痹综合征：病理生理学和以结果为导向的治疗管理综述

背景：血管麻痹综合征 (VPS) 定义为尽管心脏指数正常或增加，但由于深度血管舒张和全身血管阻力 (SVR) 丧失导致的全身性低血压，其特征是对标准剂量的血管加压药反应不足，以及发病率和死亡率增加。9%–44% 的心脏手术患者在体外循环 (CPB) 后发生。CPB 后的潜在病理生理学包括对血管升压药的抗性（Ca ^2+失活一方面是电压门控通道），另一方面是血管扩张剂（SIRS、iNOS 和低 AVP）的过度激活。使用血管紧张素转换酶抑制剂（ACE-I）、钙通道阻滞剂、胺碘酮、肝素、低心脏储备（EF < 35%）、症状性充血性心力衰竭和糖尿病是心脏手术后VPS的围手术期危险因素成年人。迄今为止，关于 VPS 的以结果为导向的治疗管理尚未达成共识。血管加压药如去甲肾上腺素（NE；0.025–0.2 µg/kg/min）和加压素（0.06 U/min 或 6 U/h 中位剂量）是治疗的首选。当灌注目标（平均动脉压 [MAP] >