Comprehensive Hemodynamic Monitoring of Stage 1 Shunted Single Ventricle Circulation
Pranava Sinha1, Nina Deutsch, MD1, Murfad S. Peer, MD1, Lok M. Sinha, MD1, Manan Desai, MD1, Syed Bukhari, MD1, Mark Nuszkowski1, Erin Montague1, Richard Jonas1, Dimitri Starostin, BC2, Nikolai Krivitski, BC3.
1Children's National Medical Center, Washington, DC, USA, 2Research and Development, Transonic Systems Inc., Ithaca, NY, USA, 3Research and Development, Transonic Systems Inc, Ithaca, NY, USA.
Objective(s): Single Ventricle circulation with a shunt (SVS) is inherently unstable. Parameters for assessing cardiac index (CI) such as SVC saturations, serum lactate or pH are indirect surrogates of perfusion, and no direct CO measurement tool is available. CI can be measured either directly using miniature transit time ultrasound flow probes (MTTUP) placed on great vessels or indirectly by generation of ultrasound dilution (UD) curves based on changes of blood ultrasound velocity upon saline injection. The aim of this study is to investigate the ability of MTTUP placed on the shunt or aorta to provide CI and Qp/Qs using UD techniques, thus providing comprehensive monitoring of SVS circulation using a single probe.
Methods: Six 3-5kgs swine underwent surgical creation of SVS. Aortic (Qs) and shunt flows (Qp) were directly measured with MTTUP. UD curves were obtained by intravenous injections of normal saline. Qp/Qs from direct TTUP and from UD were compared.
Results: 29 comparisons between Qp/Qs by MTTUP and UD were obtained. Mean Qp/Qs was 0.60(0.2- 2.15). Qp/Qs obtained using UD strongly correlated (R= 0.89)(Figure 1A) with ratio of directly measured Qp/Qs by MTTUP.Bland-Altman plot indicates small bias (<0.1,SD = 0.165) between the two methods (Figure 1B).
Conclusions: A single MTTUP placed either on the aorta or the shunt can provide comprehensive hemodynamic measurements in SVS by combination of ultrasound dilution to estimate Qp and Qs.