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Peripheral vascular decoupling in porcine endotoxic shock
Feras Hatib1, Jos R C Jansen, Michael R Pinsky
1Edwards Lifesciences, Critical Care, Research and Development Department, Irvine, California, USA.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|June 25, 2011
Summary
Sepsis alters blood vessel tone, affecting cardiac output measurements. Central and peripheral pressure differences indicate a need for new algorithms to accurately assess cardiac output in septic shock.
Area of Science:
- Cardiovascular Physiology
- Hemodynamics
- Critical Care Medicine
Background:
- Cardiac output (CO) estimation relies on arterial pressure waveforms, assuming consistent vascular properties.
- Sepsis can disrupt normal vasomotor tone, potentially invalidating these assumptions and degrading CO estimates.
- Accurate CO monitoring is crucial for managing septic shock.
Purpose of the Study:
- To investigate if sepsis differentially alters central and peripheral vasomotor tone.
- To assess the impact of this decoupling on arterial input impedance (Z), vascular compliance (C), and resistance (R).
- To determine if this decoupling explains reduced precision of peripheral arterial pressure-based CO algorithms in septic shock.
Main Methods:
- Anesthetized pigs (n=19) underwent fluid-resuscitated endotoxic shock.
- Measured aortic, femoral, and radial artery pressures and flows.
- Calculated Z, C, and R using FFT and a two-element Windkessel model from central and peripheral data.
Main Results:
- Despite restored aortic and radial blood flow, mean arterial pressure decreased uniformly.
- Aortic pulse pressure exceeded peripheral pulse pressure.
- Calculated Z and C differed significantly when derived from aortic versus radial pressures, indicating central-to-peripheral decoupling.
Conclusions:
- Sepsis-induced central-to-peripheral vasomotor tone decoupling is quantifiable.
- This decoupling likely explains decreased accuracy of peripheral arterial pressure-based CO algorithms in septic shock.
- New algorithms accounting for vascular decoupling may be needed for precise CO assessment in sepsis.
