The Dependent Variable
Rebuilding cardiovascular physiology from first principles.
| Platform |  | Pricing | Freemium | Publishes | Twice weekly |
|---|---|---|---|---|---|
| Issues | 17 | Founded | 3 months ago | Last Issue | 7 days ago |
| Active | |||||
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thedependentvariable.comLatest Issues
The Afterload Problem
Afterload is usually taught as “the load the heart pumps against.”
It sounds straightforward until you ask what that load actually is.
Arterial pressure? Systemic vascular resistance? Aortic impedance? Effective arterial elastance? Ventri...
The Pressure That Wasn’t Measured
A brief extra post outside my usual schedule. I came across this paper while reviewing the recent haemodynamics literature and thought it was too relevant to leave until later. It connects directly with two themes I’ve been exploring here...
The Preload Problem
Preload, Frank–Starling and filling pressure are not the same thing. A first-principles rethink of what actually limits cardiac output.
In 2001, James Norton went through the physiology literature looking at how preload was defined. He fou...
What Actually Happens When We Give Fluid or Vasopressors?
We give fluid and vasopressors every day, and we usually describe what they do with a small set of familiar phrases. Fluid increases preload. Noradrenaline increases venous return. Venoconstriction mobilises stressed volume. Vasopressors in...
Episode VIII: The Dependent Variable
Venous Return Wars
The Venous Return Wars have raged for decades. Champions have arisen on both sides. Guyton rules the haemodynamic empire, and his apprentice Magder defends it. The physics is strong with the rebels, but they have yet to...
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Rebuilding cardiovascular physiology from first principles.
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