Data_Sheet_1_Definitions of low cardiac output syndrome after cardiac surgery and their effect on the incidence of intraoperative LCOS: A literature review and cohort study.docx

ObjectivesLow cardiac output syndrome (LCOS) is a serious complication after cardiac surgery. Despite scientific interest in LCOS, there is no uniform definition used in current research and clinicians cannot properly compare different study findings. We aimed to collect the LCOS definitions used in literature and subsequently applied the definitions obtained to existing data to estimate their effect on the intraoperative LCOS incidences in adults, children and infants.
DesignThis is a literature review, followed by a retrospective cohort study.
SettingThis is a single-institutional study from a university hospital in the Netherlands.
ParticipantsPatients from all ages undergoing cardiac surgery with cardiopulmonary bypass between June 2011 and August 2018.
InterventionsWe obtained different definitions of LCOS used in the literature and applied these to data obtained from an anesthesia information management system to estimate intraoperative incidences of LCOS. We compared intraoperative incidences of LCOS in different populations based on age (infants, children and adults).
Measurements and main resultsThe literature search identified 262 LCOS definitions, that were applied to intraoperative data from 7,366 patients. Using the 10 most frequently published LCOS definitions, the obtained incidence estimates ranged from 0.4 to 82% in infants, from 0.6 to 56% in children and from 1.5 to 91% in adults.
ConclusionThere is an important variety in definitions used to describe LCOS. When applied to data obtained from clinical care, these different definitions resulted in large distribution of intraoperative LCOS incidence rates. We therefore advocate for standardization of the LCOS definition to improve clinical understanding and enable adequate comparison of outcomes and treatment effects both in daily care and in research.

### 研究目标
心脏术后低心排血量综合征（Low Cardiac Output Syndrome, LCOS）是一类严重的手术并发症。尽管学界对LCOS已有诸多研究关注，但当前临床与科研领域尚未形成统一的定义，导致临床医师无法对不同研究的结果开展合理比较。本研究旨在收集已发表文献中报道的各类LCOS定义，并将所获定义应用于现有临床数据集，以评估其对成人、儿童及婴幼儿术中LCOS发生率的影响。
### 研究设计
本研究为文献综述结合回顾性队列研究的混合设计。
### 研究场景
本研究为单中心研究，数据来源于荷兰某大学附属医院。
### 研究对象
2011年6月至2018年8月期间，所有接受体外循环心脏手术的各年龄段患者。
### 干预措施
本研究首先收集了已发表文献中报道的各类LCOS定义，随后将这些定义应用于从麻醉信息管理系统获取的临床数据集，以估算术中LCOS的发生率；同时基于年龄分层（婴幼儿、儿童、成人），比较不同人群的术中LCOS发生率差异。
### 测量指标与主要结果
文献检索共识别出262种LCOS定义，将其应用于7366例患者的术中临床数据集后，采用发表频次最高的10种LCOS定义进行分析，结果显示婴幼儿LCOS发生率区间为0.4%至82%，儿童为0.6%至56%，成人为1.5%至91%。
### 研究结论
当前用于描述LCOS的定义存在显著异质性。将这些不同定义应用于临床护理数据集时，会导致术中LCOS发生率的估算结果出现较大分布差异。因此，本研究呼吁统一LCOS的定义，以提升临床认知水平，并为日常临床护理与科研工作中结局指标及治疗效果的合理比较提供支撑。