In the ambulance, a good physical exam and maternal hx can be done, pre and post ductal sp02, ekg, glucose, vascular access,etc...What about the remainder of the exam? Lung sounds, heart sounds, ekg, capilary refil? The developing hepatomegaly makes me suspect hepatic congestion secondary to R sided heart failure/RV outflow obstruction given the information we have thus far....standing by awaiting further.