BACKGROUND Cardiac output measurements may inform diagnosis and provide guidance of therapeutic interventions in patients with hemodynamic instability. The FloTrac™ algorithm uses uncalibrated arterial pressure waveform analysis to estimate cardiac output. Recently, a new version of the algorithm has been developed. The aim was to assess the agreement between FloTrac™ and routinely performed cardiac output measurements obtained by critical care ultrasonography in patients with circulatory shock. METHODS A prospective observational study was performed in a tertiary hospital from June 2016 to January 2017. Adult critically ill patients with circulatory shock were eligible for inclusion. Cardiac output was measured simultaneously using FloTrac™ with a fourth-generation algorithm (COAP) and critical care ultrasonography (COCCUS). The strength of linear correlation of both methods was determined by the Pearson coefficient. Bland-Altman plot and four-quadrant plot were used to track agreement and trending ability. RESULT Eighty-nine paired cardiac output measurements were performed in 17 patients during their first 24 h of admittance. COAP and COCCUS had strong positive linear correlation (r 2 = 0.60, p < 0.001). Bias of COAP and COCCUS was 0.2 L min-1 (95% CI - 0.2 to 0.6) with limits of agreement of - 3.6 L min-1 (95% CI - 4.3 to - 2.9) to 4.0 L min-1 (95% CI 3.3 to 4.7). The percentage error was 65.6% (95% CI 53.2 to 77.3). Concordance rate was 64.4%. CONCLUSIONS In critically ill patients with circulatory shock, there was disagreement and clinically unacceptable trending ability between values of cardiac output obtained by uncalibrated arterial pressure waveform analysis and critical care ultrasonography. TRIAL REGISTRATION Clinicaltrials.gov, NCT02912624, registered on September 23, 2016.

中文翻译：

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第四代 FloTrac 和重症监护超声在循环休克患者心输出量测量方面的差异：一项前瞻性观察研究。

背景技术心输出量测量可为血流动力学不稳定患者的诊断提供信息并指导治疗干预。FloTrac™ 算法使用未经校准的动脉压力波形分析来估计心输出量。最近，该算法的新版本已经开发出来。目的是评估 FloTrac™ 与循环性休克患者通过重症监护超声检查获得的常规心输出量测量值之间的一致性。方法 2016 年 6 月至 2017 年 1 月在一家三级医院进行前瞻性观察性研究。成人循环休克危重患者符合纳入标准。使用具有第四代算法 (COAP) 和重症监护超声 (COCCUS) 的 FloTrac™ 同时测量心输出量。两种方法的线性相关强度由 Pearson 系数确定。Bland-Altman 图和四象限图用于跟踪一致性和趋势能力。结果 17 名患者在入院前 24 小时内进行了 89 对心输出量测量。COAP 和 COCCUS 具有很强的正线性相关性（r 2 = 0.60，p < 0.001）。COAP 和 COCCUS 的偏差为 0.2 L min-1（95% CI - 0.2 至 0.6），一致性限制为 - 3.6 L min-1（95% CI - 4.3 至 - 2.9）至 4.0 L min-1（95% CI 3.3 至 4.7)。百分比误差为 65.6%（95% CI 53.2 至 77.3）。一致率为64.4%。结论 在循环休克的危重患者中，通过未校准的动脉压波形分析和重症监护超声检查获得的心输出量值之间存在分歧和临床上不可接受的趋势能力。试验注册 Clinicaltrials.gov，NCT02912624，注册于 2016 年 9 月 23 日。