Pulse Pressure Question?

[newls1]

Ok so i know that arteriole constriction increases diastolic pressure which causes a decreasing pulse pressure in hemmorrhagic shock. me and a couple of my EMT buddies have been arguing as to why this is the cause. can anyone elaborate? thank you!

 

[Aidey]

I don't think I understand your question completely. Are you asking why the arterioles constrict during hemorrhagic shock?

 

[newls1]

I don't think I understand your question completely. Are you asking why the arterioles constrict during hemorrhagic shock?

no im asking "when they constrict, why does the increase in diastolic pressure, cause a decreasing pulse pressure"?

 

[JPINFV]

Pulse pressure is simply the systolic minus the diastolic. So if the diastolic rises faster than the systolic, you will have a decreasing pulse pressure. Furthermore, at the same time that the diastolic is rising, the systolic is falling since the loss of volume is also causing a decrease in venous return.

 

[medicdan]

What is a wide (90) pulse pressure indicative of, on a completely healthy/stable patient, apart from good ears on the EMT? Last week, at a BP clinic, I had a patient with a large pulse pressure-- but no explination, and no PMH.

 

[nova5267]

What is a wide (90) pulse pressure indicative of, on a completely healthy/stable patient, apart from good ears on the EMT? Last week, at a BP clinic, I had a patient with a large pulse pressure-- but no explination, and no PMH.

It probably has to do with the cardiac preload and the stroke volume correlation. A decreased cardiac preload can cause a wide pulse pressure but no other side effects may be seen! It may or may not become dangerous for the patient

 

[ccmedic]

What is a wide (90) pulse pressure indicative of, on a completely healthy/stable patient, apart from good ears on the EMT? Last week, at a BP clinic, I had a patient with a large pulse pressure-- but no explination, and no PMH.

Depends. Trends are much more valuable than single data points. Atherosclerosis can actually be a cause. Mechanically, the vasculature can be modeled as a system of dashpots (or capacitors, if you're more electrically inclined) and resistors. The dashpots represent the elasticity of the arteries. When an artery (such as the aorta) expands as blood flows from the heart, the elasticity of the aorta helps to dampen a sudden pressure change and thus helps maintains a more constant flow. The resistors represent the resistance inherent in a fluid flowing through a conduit (such as the arteries).

Since brevity is the soul of wit, the narrowing of artery walls due to atherosclerosis modulates the resistance function in this system and thus can account for the wide pulse pressure. Similarly, arteriosclerosis (as a reminder- the hardening of the arteries) modulates the dashpot function of the system due to loss of artery elasticity. Thus a beautiful example of the marriage of mathematics and pure science with medicine.