Detailed Description: My training in echocardiography methods has allowed me to perform physiology based cardiovascular research both in human neonates and animal experimental models. The cornerstone of my research is to improve our understanding of the neonatal heart and how acute cardiovascular physiologic change is influenced by disease processes and therapeutic interventions.
1. Physiology of the Ductus Arteriosus; Over the past 5 years our work has focused on the physiologic effects of PDA ligation. We were the first to describe the Post-Ligation Cardiac Syndrome (PLCS) characterized by oxygenation failure and hemodynamic instability, 8-12 hours after surgical intervention [Teixeira et al, J Perinat 2008]. We subsequently demonstrated that the nature of left ventricular (LV) dysfunction relates to altered loading conditions [McNamara et al, J Thoracic & Cardiovasc Surg 2010]. Recently we have developed a predictive model, based on echo-derived estimation of left ventricular output, and demonstrated that commencement of prophylactic afterload reducing treatment with intravenous milrinone leads to improvement in neonatal outcomes. Current studies are investigating the value of plasma troponin and adrenal gland performance testing in the perioperative period.
2. Adjunctive Pulmonary Vasodilator Therapy in Persistent Pulmonary Hypertension of the Newborn. We were the first to report improvement in oxygenation in neonates with resistant PPHN with intravenous Milrinone (PDE 3 inhibitor) [McNamara et al, J of Critical Care 2006; Bassler et al. Biol Neonate 2005]. We have recently completed a pharmacological study of the effects of milrinone in PPHN; the manuscript is currently under review. Recently, we have completed a similar study that demonstrates the efficacy of Vasopressin in iNO responsive patients.
3. Echocardiography and Animal Experimental studies: High frequency ultrasound (13-15 MHz) using a small iL13 probe has allowed us to image small animal models. We are the first group to conduct dynamic evaluations of neonatal rodent myocardial function and have performed more than 1000 animal evaluations to date. My expertise in animal echocardiography has allowed me to establish many collaborations. We have successfully used echocardiography in both rodent and neonatal porcine models to investigate the effect of resuscitation gas mixtures, ventilation and drugs on myocardial performance (McCaul et al, Resuscitation 2006; 68:267-75, McCaul et al, Anaesthesia & Analgesia 2006; 102(2):542-8). We have also pioneered the assessment of myocardial performance and pulmonary hemodynamics in a neonatal rodent (< 20 grams) model of hypoxia using high frequency echocardiography and contributed to several publications using these techniques.
Within the Department of Physiology
Outside the Department of Physiology:
Ron Clyman University of San Francisco
Jeff Reese Vanderbilt university, Nashville