Comparison of non-invasive cardiac output measurement and pulse-indicated continuous cardiac output monitoring for determining hemodynamic parameters in patients with critical septic shock: a prospective study

Abstract Objective To compare non-invasive cardiac output measurement (NICOM) and pulse-indicated continuous cardiac output (PiCCO) monitoring for determining hemodynamic parameters in patients with critical septic shock and to analyze the correlation between the two techniques. Methods Patients with critical septic shock admitted to the Department of Critical Care Medicine at Peking Union Medical College Hospital from April to December 2015 who required hemodynamic monitoring were enrolled prospectively. Cardiac output (CO) and stroke volume variation (SVV) were measured by NICOM and PiCCO in all patients and compared by Spearman’s correlation and Bland–Altman analyses. Trial registration: ChiCTR-OOB-17014129. Registered 24 September 2017. retrospectively registered. Results Thirty-one patients were included in the study (19 males and 12 females, mean age ± standard deviation, 55.5 ± 18.1 years), with a mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score of 22.7±6.1. There was no significant difference in CO measured by the NICOM and PiCCO methods (5.10 [4.35, 6.50] L/min vs. 4.89 [4.34, 6.23] L/min; P > 0.05). However, SVV measured by NICOM was significantly higher than that measured by PiCCO (13.00 [11.00, 16.00] vs. 12.00 [9.00, 15.00]; P = 0.009). CO and SVV determined by NICOM and PiCCO were significantly correlated according to Spearman’s correlation analysis (CO: R = 0.904, P < 0.001, 95% confidence interval 0.932–1.135; SVV: R = 0.841, P < 0.001, 95% confidence interval 0.601–0.786). Bland–Altman analysis revealed a bias in mean CO of 0.21 L/min (P = 0.0032) and limits of agreement of −1.12 to 1.54 L/min; and a bias in mean SVV of 1.56 (P < 0.0001) and limits of agreement of −2.56 to 5.68. Conclusions Hemodynamic parameters monitored by NICOM and PiCCO differed in patients with critical septic shock, but the correlation between the two methods was good. Use of non-invasive NICOM may therefore help to reduce complications associated with invasive procedures. Keywords: Septic shock; Non-invasive cardiac output measurement; Cardiac output; stroke volume variation