Noninvasive Measurements of Cardiac Hemodynamic and Tissue Perfusion Indices in Normal Infants
Purpose: Neonatal care lacks reproducible and clinically relevant measurements of hemodynamic indices (stroke volume, SV; cardiac output, CO; cardiac index, CI) and end-organ oxygenation (cerebral, renal, splanchnic). Two technological innovations have allowed non-invasive, real-time measurement of both: Electrical cardiometry (EC) detects ascending aorta erythrocyte orientation changes to provide hemodynamics; near-infrared spectroscopy (NIRS) assesses regional oxygen delivery as regional oxygen saturation (rSO2). Despite their promise EC and NIRS have not been studied thoroughly in surgical infants. A first step is to verify that EC and NIRS provide reproducible measurements that correlate under steady-state conditions in healthy infants.
Methods: An IRB-approved observational study with parental consent of EC (ICON, Cardiotronic Inc., La Jolla, CA) and NIRS (INVOS, Covidien/Somanetics, Boulder, CO) in 3 healthy asymptomatic infants (1.9-2.5 kg, 34-41 wk gestation, 2-15 wk of age) over 5 hours of observation. Coefficients of variation (CoV) estimated reproducibility. Linear regression gave correlations between hemodynamic indices and rSO2, p significant at < 0.05.
Results: EC gave measurements of CO and CI with CoV that ranged from 11.2%-15.6%, SV having more variability, 16.4%-18.0%. Cerebral rSO2 were most consistent (CoV 5.2%-9.4%), followed by renal (8.1%-14.8%) and splanchnic rSO2 (18.4%-20.6%). Strongest correlations between EC and NIRS were with SV and renal perfusion (r=0.58, p<0.0001), but significant correlations also were present between hemodynamic indices and cerebral (with CO and CI; r=0.39, p<0.0001) and splanchnic rSO2 (with CI; r=0.38 p<0.0001).
Conclusions: Data variation limits clinical decisions based on single EC and NIRS measurements. Research is needed to determine the value of EC and NIRS in detecting trends over longer periods, especially during the therapeutic administration of cardiotonic and vasoactive medications. Of interest is whether the technology can characterize the changes in hemodynamics and perfusion associated with surgical conditions such as necrotizing enterocolitis, gastroschisis, and patent ductus arteriosus.
American Pediatric Surgeons Association Annual Meeting (APSA)
San Antonio, TX
Long, Eric L., Barbara Weaver, Joshua Glenn, Robert L. Vogel, Andrew Bozeman, Brandon Lerner, Renee Kleris, Joseph M. Van De Water, Don K. Nakayama, Misael Rodriguez.
"Noninvasive Measurements of Cardiac Hemodynamic and Tissue Perfusion Indices in Normal Infants."
Biostatics Faculty Presentations.