November 1, 1986Circulation
Systemic vascular resistance: an unreliable index of left ventricular afterload.
Why the study?
Does systemic vascular resistance accurately reflect left ventricular afterload compared to left ventricular end-systolic wall stress during pharmacological interventions?
Population
8 dogs instrumented with central aortic microtip and Swan-Ganz thermodilution catheters
Comparison
Infusions of nitroprusside, methoxamine… vs Control conditions
Design
Preclinical
Authors
Discussion
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Member takes
Implication
SVR may misrepresent LV afterload during vasopressor use; challenges its validity as surrogate and leaves open human validation of sigma es.
Structured PICO
Does systemic vascular resistance accurately reflect left ventricular afterload compared to left ventricular end-systolic wall stress during pharmacological interventions?
P
Population
8 dogs instrumented with central aortic microtip and Swan-Ganz thermodilution catheters
I
Intervention
Infusions of nitroprusside, methoxamine, dobutamine, and norepinephrine to alter left ventricular afterload and contractility
C
Comparator
Control conditions (baseline values before each drug infusion)
O
Outcome
Relationship between systemic vascular resistance (SVR) and left ventricular end-systolic wall stress (sigma es)surrogate
Systemic vascular resistance is an unreliable index of left ventricular afterload as it reflects only peripheral arteriolar tone and can change discordantly with true left ventricular systolic wall force.
Cite This Study
Lang et al. (1986) studied this question.