Department of Internal Medicine, University of São Paulo School of Medicine, Pacaembu, São Paulo, State of São Paulo 01246-000, Brazil.
Department of Emergency Medicine, Wayne State University School of Medicine, Detroit, MI 48201, USA.
Resuscitation. 2018 Feb;123:1-7. doi: 10.1016/j.resuscitation.2017.12.003. Epub 2017 Dec 5.
To identify whether any level of end-tidal carbon dioxide (ETCO) measured during cardiopulmonary resuscitation (CPR) correlates with return of spontaneous circulation (ROSC) or survival in adults experiencing cardiac arrest in any setting.
Systematic review. We included randomized controlled trials, cohort studies, and case-control studies of adult cardiac arrest in any setting that reported specific (rather than pooled) ETCO values and attempted to correlate those values with prognosis. Full-text articles were searched on EmBASE, MEDLINE, and Cochrane Database. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) guidelines were followed, assigning levels of quality to all evidence used in the meta-analysis.
Seventeen observational studies, describing a total of 6198 patients, were included in the qualitative synthesis, and five studies were included in the meta-analysis. The available studies provided consistent but low-quality evidence that ETCO measurements ≥10mmHg, obtained at various time points during CPR, are substantially related to ROSC. Additional cut-off values were also found. Initial ETCO or 20-min ETCO>20mmHg appears to be a better predictor of ROSC than the 10mmHg cut off value. A ETCO<10mmHg after 20min of CPR is associated with a 0.5% likelihood of ROSC.
Based upon existing evidence, ETCO levels do seem to provide limited prognostic information for patients who have experienced cardiac arrest. Given the many potential confounders that can influence initial ETCO levels, extreme or trending values may be more useful than static mid-range levels. Additional well-designed studies are needed to define optimal timing for the measurement of ETCO for prognostic purposes.
确定心肺复苏（CPR）期间测量的任何水平的呼气末二氧化碳（ETCO）是否与任何情况下发生心脏骤停的成年人的自主循环恢复（ROSC）或生存相关。
系统评价。我们纳入了在任何情况下报告特定（而非汇总）ETCO 值并尝试将这些值与预后相关联的成人心脏骤停的随机对照试验、队列研究和病例对照研究。在 EmBASE、MEDLINE 和 Cochrane 数据库上搜索全文文章。遵循推荐评估、制定与评价（GRADE）指南，为荟萃分析中使用的所有证据分配质量等级。
纳入了 17 项观察性研究，共描述了 6198 例患者，进行了定性综合分析，并纳入了 5 项研究进行荟萃分析。现有研究提供了一致但质量较低的证据，表明在 CPR 过程中各个时间点测量的 ETCO 值≥10mmHg 与 ROSC 密切相关。还发现了其他截止值。初始 ETCO 或 20 分钟 ETCO>20mmHg 似乎比 10mmHg 截止值更能预测 ROSC。CPR 20 分钟后 ETCO<10mmHg 与 ROSC 的可能性为 0.5%。
根据现有证据，ETCO 水平似乎确实为经历过心脏骤停的患者提供了有限的预后信息。鉴于许多可能影响初始 ETCO 水平的潜在混杂因素，极端或趋势值可能比静态中值范围更有用。需要更多设计良好的研究来确定测量 ETCO 以进行预后目的的最佳时间。
