Echocardiography showed no significant difference in cardiac output measurements compared to thermodilution (MD -0.14; 95% CI, -0.30 to 0.02; P = 0.08), suggesting the techniques may be interchangeable under certain conditions.
Meta-Analysis (n=1,996)
Does cardiac output measurement via echocardiography provide consistent and interchangeable results compared to thermodilution in critically ill patients?
Echocardiography and thermodilution show no significant overall difference in cardiac output measurements and may be interchangeable under certain conditions in critically ill patients.
Effect estimate: MD -0.14 (95% CI -0.30 to 0.02)
p-value: p=0.08
Echocardiography, as a noninvasive hemodynamic evaluation technique, is frequently used in critically ill patients. Different opinions exist regarding whether it can be interchanged with traditional invasive means, such as the pulmonary artery catheter thermodilution (TD) technique. This systematic review aimed to analyze the consistency and interchangeability of cardiac output measurements by ultrasound (US) and TD. Five electronic databases were searched for studies including clinical trials conducted up to June 2019 in which patients' cardiac output was measured by ultrasound techniques (echocardiography) and TD. The methodological quality of the included studies was evaluated by two independent reviewers who used the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), which was tailored according to our systematic review in Review Manager 5.3. A total of 68 studies with 1996 patients were identified as eligible. Meta-analysis and subgroup analysis were used to compare the cardiac output (CO) measured using the different types of echocardiography and different sites of Doppler use with TD. No significant differences were found between US and TD (random effects model: mean difference MD, -0.14; 95% confidence interval, -0.30 to 0.02; P = 0.08). No significant differences were observed in the subgroup analyses using different types of echocardiography and different sites except for ascending aorta (AA) (random effects model: mean difference MD, -0.37; 95% confidence interval, -0.74 to -0.01; P = 0.05) of Doppler use. The median of bias and limits of agreement were -0.12 and ±0.94 L/min, respectively; the median of correlation coefficient was 0.827 (range, 0.140-0.998). Although the difference in CO between echocardiography by different types or sites and TD was not entirely consistent, the overall effect of meta-analysis showed that no significant differences were observed between US and TD. The techniques may be interchangeable under certain conditions.
Zhang et al. (Thu,) conducted a meta-analysis in Critically ill patients requiring cardiac output monitoring (n=1,996). Echocardiography vs. Thermodilution was evaluated on Mean difference in cardiac output (L/min) (MD -0.14, 95% CI -0.30 to 0.02, p=0.08). Echocardiography showed no significant difference in cardiac output measurements compared to thermodilution (MD -0.14; 95% CI, -0.30 to 0.02; P = 0.08), suggesting the techniques may be interchangeable under certain conditions.