Emergency department non-invasive cardiac output study (EDNICO): a feasibility and repeatability study

D Mcgregor,S Sharma,S Gupta,S Ahmad,T Godec,Tim Harris

doi:10.1186/s13049-019-0586-6

Abstract

BackgroundThere is little published data investigating non-invasive cardiac output monitoring in the emergency department (ED). We assessed six non-invasive fluid responsiveness monitoring methods which measure cardiac output directly or indirectly for their feasibility and repeatability of measurements in the ED: (1) left ventricular outflow tract echocardiography derived velocity time integral, (2) common carotid artery blood flow, (3) suprasternal aortic Doppler, (4) bioreactance, (5) plethysmography with digital vascular unloading method, and (6) inferior vena cava collapsibility index.MethodsThis is a prospective observational study of non-invasive methods of assessing fluid responsiveness in the ED. Participants were non-ventilated ED adult patients requiring intravenous fluid resuscitation. Feasibility of each method was determined by the proportion of clinically interpretable measurements from the number of measurement attempts. Repeatability was determined by comparing the mean difference of two paired measurements in a fluid steady state (after participants received an intravenous fluid bolus).Results76 patients were recruited in the study. A total of 207 fluid responsiveness measurement sets were analysed. Feasibility rates were 97.6% for bioreactance, 91.3% for vascular unloading method with plethysmography, 87.4% for common carotid artery blood flow, 84.1% for inferior vena cava collapsibility index, 78.7% for LVOT VTI, and 76.8% for suprasternal aortic Doppler. The feasibility rates difference between bioreactance and all other methods was statistically significant.ConclusionOur study shows that non-invasive fluid responsiveness monitoring in the emergency department may be feasible with selected methods. Higher repeatability of measurements were observed in non-ultrasound methods. These findings have implications for further studies specifically assessing the accuracy of such non-invasive cardiac output methods and their effect on patient outcome in the ED in fluid depleted states such as sepsis.

Highlights

There is little published data investigating non-invasive cardiac output monitoring in the emergency department (ED)
Fluid responsiveness is commonly defined as a stroke volume increase of at least 10% following a fluid bolus of 200-500mls 10–15 min [8]
The stroke volume was simultaneously measured by LVOT Left ventricular outflow tract velocity time integral (VTI), common carotid artery blood flow monitoring (CCABF), bioreactance, and plethysmography using the vascular unloading technique (PVUT)

Summary

Introduction

Targeting intravenous fluid therapy to fluid responsiveness and fluid tolerance, and stroke volume/cardiac output, may optimise tissue oxygenation and reduce the risk of tissue oedema. In the intensive care setting, fluid resuscitation is frequently guided by invasive monitoring of cardiac output, previously with Pulmonary Artery Catheterisation (PAC), and commonly with less invasive devices, such as arterial pulse pressure analysis or oesophageal Doppler [9]. These methods are invasive and unsuitable for routine monitoring in the Emergency Department [10, 11]

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