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What Is Average Blood Flow And Pressure In The Vena Cava?

Posted on Mon, 21 Apr 2014

Question: What are typical blood flows and pressures in the vena cava as the flow approaches the heart for an adult male for the following conditions: a. at rest b. moderate activity, walking on level c. intense activity, i.e., climbing stairs Also, what are the heart discharge pressures for the same conditions As the pressures are likely to be pulsating please indicate average pressures or pressure ranges

Answered by Dr. Saumya Mittal (3 hours later)

Brief Answer: Its very very variable Detailed Answer: Hi I am Dr Saumya Mittal I will try to answer your query. First be clear that there are a huge number of factors which decide the flow of the blood in the blood vessels. These include the viscocity of blood the volume of blood the calibre of the vessel the lumen of the vessel the lipid profile of the vessel the heart rate the blood pressure the medicines being taken the activity being performed the effect of gravity the body weight. Assuming that the contributing factors are all normal, the average peak velocities during a ventricular systole ranged 30-45 cm/sec in the inferior and 10-35 cm/sec in the superior vena cava. The velocity increases between 36-76% of the resting levels during exercise. (Source: http://circres.ahajournals.org/content/23/3/349.full.pdf) I hope that answers your query. Any further related query is welcome. Dr S Mittal

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Saumya Mittal (3 days later)

Please supplement the answer, above, with the pressure in the vena cava that moves the blood into the heart and the discharge pressure of blood leaving the heart. I understand the variables you listed, above, but I am just interested in the power, work per unit time, that the heart generates while pumping blood. I am an engineer that designs hydraulic power systems and other types of fluid piping systems. Typical values for a normal male for the items are requested. I need intake and discharge pressures for the heart in addition to the flow data you provided to calculate power. I am interested in determining the capabilities of the human heart as a matter of general interest. Typical approximate values are acceptable. I did find the reply. I admit I over reacted, but it did take several attempts before I got to the reply which was frustrating. I did think I was following your instructions but kept getting a new screen instead of your response. Can I get a response to my follow up question or do I have to pay for further Information?

Answered by Dr. Saumya Mittal (4 days later)

Brief Answer: hope this helps Detailed Answer: sorry for the delay. i am usually not late. but some circumstances were unavoidable. the blood flow through the vena cava is essentially always the same as the blood pumped out of the heart. at rest, the flow of blood is 5.6 L/min for male and 4.9 L/min for a female. in the typical exercise conditions, the blood flow ranges from 4.0–8.0 L/min. vena cava is normally 1.5 to 2.5 cm in diameter.i guess that will help you calculate the wall pressure on the 2-3 cm segment of vena cava please note, these are average values only i hope you can design something that helps the doctors treat patients.

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Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar