You're over-thinking this bud. There's no such thing as a "PDF" feed. The RSS feed will only be able to send the plain text that you put in a post and pictures. This isn't a limitation set by WordPress, it's how the RSS works generally.
All a feed reader (Thunderbird for example) is going to see (from your latest post is:
Venous thromboembolism (VTE) is a clinical entity which includes deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE is a common medical condition affecting up to 117 patients per 100,000 population annually.1 The diagnosis of VTE is often difficult and frequently missed. Mortality in untreated PE is approximately 30%, but with adequate anticoagulant treatment, this can be reduced to 2–8%.2 The purpose of this Newsletter is to focus on the diagnosis and treatment of VTE, including PE and DVT in the emergency department (ED). In this EMCREG-International Newsletter, Dr. Charles Cairns, Associate Professor of Surgery and Medicine and Associate Chief of Emergency Medicine at the Duke University School of Medicine discusses the important disease process venous thromboembolism (VTE) which includes deep venous thrombosis and pulmonary embolism from the perspective of emergency medicine.
And then the link to get the PDF. If that's what you want then fantastic. What this will not do is automatically pass the PDF file to the person reading the feed.
If it's just text and images then I would suggest that you provide the content directly in the post. By all means provide the PDF as well for archiving purposes by the end reader.
And no, the XML file can't "force" feed anything. Only what it is designed to push (see above).
I hope this helps!