HeartSmart® for routine optimization of blood flow and facilitation of early goal-directed therapy
Kenneth Warring-Davies1, Martin Bland2
1The Intensive Care Unit, Bradford Royal Infirmary, Bradford, West Yorkshire, UK; 2Department of Health Sciences, University of York, York, North Yorkshire, UK
Abstract: The empirical physiological formulae of the new continuous cardiac dynamic monitoring HeartSmart® technology, which involves the use of a new inverse square rule of the heart, were investigated with pulmonary artery catheter (PAC) thermodilution in the estimation of CI in diverse patients. Clinical trial data collected from 268 adult surgery or intensive care patients requiring PAC placement were obtained from 7 NHS Trust hospitals, providing 2720 paired sets of CI estimations for comparison between HeartSmart® and PAC thermodilution. For 95% of pairs of measurements, HeartSmart® values were between 57% and 164% of PAC measurements; additionally, the larger limit of agreement between HeartSmart® and PAC thermodilution (1.26 L min-1•m-2) suggests that HeartSmart® agrees with PAC thermodilution as closely as PAC thermodilution agrees with itself. HeartSmart® can also estimate CI in the extreme circumstances of shock/sepsis, as indicated by PAC thermodilution CI values that were hypo- or hyperdynamic based on systemic inflammatory response syndrome criteria. In CI measurements for hypo- or hyperdynamic values that were matched between HeartSmart® and PAC thermodilution, the difference in total volumes and average CI measurements between the two methods was less than 5%. For unmatched hypo- or hyperdynamic values, the difference between total volumes and average CI measurements was less than 33% – an acceptable percentage of difference or error even for normal values of CI. HeartSmart® tracked PAC thermodilution CI hypodynamic values 98.2% of the time and hyperdynamic values 97.6% of the time. These findings show that CI estimations provided by the HeartSmart® empirical physiological formulae are comparable to those obtained using PAC thermodilution. HeartSmart® removes many of the technical barriers that prevent the routine adoption and practice of early goal-directed therapy, and represents a simple, reliable method of estimating CI and other hemodynamic variables at the bedside or in departments other than the Intensive Care Unit.
Keywords: cardiac index, early goal-directed therapy, HeartSmart®, cardiodynamics, blood flow
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