Clearsight™ use for haemodynamic monitoring during the third trimester of pregnancy – a validation study

Abstract

BackgroundWe assessed the validity of Clearsight™ as a non-invasive cardiac output and stroke volume monitoring device, comparing it with transthoracic echocardiography measurements during the third trimester of pregnancy. MethodsMeasurements obtained from Clearsight™ were compared with those from echocardiography as the gold standard. The precision and accuracy of the Clearsight™ was measured using the Bland and Altman method. Clinical agreement with echocardiography was assessed using the agreement tolerability index. ResultsMeasurements were recorded from 44 pregnant women with a median [IQR range] gestational age of 33 [30–37] weeks. We found that Clearsight™ measurements presented a systematic overestimation of cardiac output, with mean bias [CI 95%] of 2.7 [2.3–3.0] L/min, with limits of agreement of −0.1 to 5.4 L/min. It overestimated stroke volume, with a bias of 29.5 [25.0–33.4] mL and a limit of agreement of −1.6 to 60.1 mL. In addition, the analysis of cardiac output showed a percentage of error of 41% and intra-class correlation [CI 95%] of 0.37 [0.17 to 0.53, P <0.001]. For stroke volume, the percentage of error was 40% and intra-class correlation 0.16 [−0.1 to 0.34; P=0.27]. We found that agreement tolerability index scores were unacceptable. We evaluated the ability of the device to track changes in cardiac output by inducing a left lateral decubitus position, but the analysis was inconclusive. ConclusionThe agreement between Clearsight™ and the echocardiography measurements of cardiac output and stroke volume were not within an acceptable range in the third trimester of pregnancy.