University of Twente Student Theses


Non-invasive continuous cardiac output monitoring using transthoracic echocardiography (TTE) in ICU patients

Duijn, J.G.A. den (2022) Non-invasive continuous cardiac output monitoring using transthoracic echocardiography (TTE) in ICU patients.

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Embargo date:8 February 2025
Abstract:Introduction: Patients admitted to the intensive care unit (ICU) are often hemodynamically unstable or at risk of becoming unstable. Sometimes more advanced hemodynamic monitoring is needed, for example the measurement of the cardiac output (CO). This is mostly done with gold standard techniques as the pulmonary artery catheter (PAC), or the Pulse index Contour Cardiac Output (PiCCO). However, these techniques only measure the CO intermittently, and are invasive to the patient. A non-invasive technique to measure the CO is transthoracic echocardiography (TTE). However, TTE cannot measure the CO continuously as opposed to the current gold standards. As the current methods are not capable of measuring the CO non-invasively and continuously, the need remains for a method that can do both. Based on these limitations a continuous CO (cCO) monitoring system using TTE was developed using an external ultrasound probe holder. Objective: The goal of this research is to evaluate the feasibility and validity of the cCO measurements in ICU patients in addition to standard CO measurements. Method: In this prospective observational study 15 healthy volunteers (HVs) and 18 ICU patients (IPs) were included. Each subject was measured once with the cCO method. The cCO method consists of 4 measurements: a manual CO measurement, a static cCO measurement, a second manual CO measurement and a dynamic CO measurement by performing a passive leg raise. The data were analysed for feasibility, validity, and differences between groups. The feasibility was evaluated using percentage of successful measurements. Results: Feasibility for the cCO method was 100% for static and 73% for dynamic cCO measurements for the HVs group. Feasibility was 88% for static and 50% for dynamic cCO measurements for IPs. Mean cCO was not significantly different between static and dynamic measurements in the HV group (t(10)=0.544, p=0.599) and in the IP group (z(9)=0.344, p=0.731). No significant difference was found for the static cCO measurements between the HVs and the IP (p=0.65), nor for the dynamic measurements (p=0.463). The mean difference between manual and automatic CO was -1.1 l/min (with limits of agreements (LOA), being -0.15 and -2.1 l/min) for the HV group and -1.4 l/min (with LOA 0.13 and 3.0 l/min) for the IP group. Mean difference between automatic and PiCCO was -3.5 l/min (with LOA at -8.6 and 5.1 l/min). Mean difference between manual and PiCCO was -1.9 l/min (with LOA at -5.5 and 1.6 l/min). A significant correlation between manual and automatic CO measurements was found in HVs (r(30) =0.776, p<0.001) and in IPs (r(32)=0.87, p<0.001). No significant correlation was found between automatic and PiCCO (r(14)=0.26, p=0.36), and between manual and PiCCO (r(14)=0.41, p=0.14). Conclusion: The cCO method is a feasible method for 100% of HVs and 88% of IPs. Measured values with the cCO method correspond strongly with manual CO and weakly correspond with PiCCO. Furthermore, no significant differences were found between healthy volunteers and ICU patients. However, further research is needed to increase sample size and further develop the cCO method. Keywords: Cardiac Output, Continuous, Transthoracic Echocardiography, External Fixator, Intensive Care Patient
Item Type:Essay (Master)
Rijnstate Hospital, Arnhem, Netherlands
Faculty:TNW: Science and Technology
Subject:44 medicine, 50 technical science in general
Programme:Technical Medicine MSc (60033)
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