Real and apparent blood pressures.?

Question

Five clear plastic, perfectly crafted demonstration models are made for educational purposes, with special attention being paid to the accuracy and detail of the complete cardiovascular system. Each has an identical heart, beating at a controlled steady 73 bpm, delivering 5 litres/min total systemic flow round the loop. All other details are completely uniform APART FROM the five aortas and principal arteries, large and small, as far down as the brachial arteries.

For interest's sake, one of the models has perfect normal (i.e., young and healthy) elasticity for its aorta and arteries.

Two others have theirs made of (a) much less compliant plastic and (b) much more compliant plastic.

The fourth has its aorta and arteries made from virtually non-compliant plastic, and (you guessed!) the fifth has its made of something like condom latex..

So, five perfect, uniform models, all having blood ejected from the ventricle at the same pressure.

What will the brachial B/P's be?

Oh, yes... and why?

Jackie O. Don't worry, -you're in godd company!
Big J,... sorry, it's the readings of B/P at the brachial artery which I'm asking about....but some of what you wrote is clearly correct.

Big J, - Thanks. You're right of course, as you can't calculate the exact values without lots of other info. But what I'm getting at is, - if a student were to obtain readings by auscultation at the five diff'rent brachial arteries, -how would they compare? And what would he/she conclude?

No best answer. ...must go to vote, -sorry

Answer 1

Abstract:
Objective: To determine the validity of an electronic health record (EHR) in the identification of patients with left ventricular dysfunction in a primary care setting.

Design: A cross-sectional study.

Setting: Nine clinics participating from the Providence Research Network (PRN) comprising 75 physicians serving approximately 200 000 patients. All clinics utilise the Logician™ EHR for all patient care activities.

Patients: The study included all PRN patients with an active chart.

Interventions: All patients with a heart failure diagnosis in the problem list were identified by database query. Left ventricular ejection fraction (LVEF) data were identified through query of local cardiology and hospital echocardiography databases. Additional LVEF data were sought in a manual search of paper charts.

Measurements and main results: To determine the problem list coding accuracy for a heart failure (HF) diagnosis we evaluated sensitivity, positive predictive value and related derived statistical measures using documented LVEF as the 'gold standard'. Of 205 755 active PRN patients, 1731 were identified with a problem list entry of HF. Based on comparison with documented LVEF, the sensitivity for problem list entry was 43.9% and 54.4% when HF was defined as an LVEFle 55% and le 40%, respectively.

Conclusion: The validity of an EHR problem list entry of HF was poor. The problem list validity could be enhanced through reconciliation with other data sources. Inaccurate EHR problem lists may have clinical consequences, including underprescribing of beneficial therapies.

Keywords: DATA QUALITY; HEART FAILURE; MEDICAL RECORD SYSTEM; QUALITY IMPROVEMENT

Document Type: Miscellaneous

Affiliations: 1: Clinical Pharmacy Specialist, Providence Health System, Portland, Oregon, USA 2: Director of Primary Care Research 3: Chief Medical Officer 4: Assistant Professor, Oregon State University College of Pharmacy, Portland, Oregon, USA 5: Director of Clinical Informatics Research and Development, Partners HealthCare System and Assistant Professor of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
follow this link for further information:

http://www.ingentaconnect.com/content/rmp/ipc/2004/00000012/00000003/art00003;jsessionid=4f5gbb40opdh7.alice

Answer 2

The more compliant the vessel, the lower the BP. Compliancy in this case would relate to vasodilation, causing decreased afterload/SVR. (When blood is ejected into the artery, the artery will expand more, decreasing the pressure in the vessel.

Coincidentaly, the less compliant vessels will harbour a higher blood pressure, because there is less room for the blood to flow through!

Did I pass? (Stroke volume is approximately 68.5ml/min) You can't accurately calculate a BP based on these numbers alone, you would need to know the ejection force of the LV, and you would need to give some number for compiancy of said vessels.

However, if you can prove me wrong, please do!

*Addendum*
I do believe that I have fully answered that question, in regards to what would the brachial BP's be given the elasticity (compliancy) of the material the pseudo-vessels are formed from.

Answer 3

I dont have one freaking clue....