Whats the mechanism of neurogenic shock causing decrease in CO ?
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Step I Neurogenic shock
Started by Sonia usmle
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no more sympathetic control of vascular tone --> decrease in total peripheral resistance that can't be compensated for with autonomics
Autonomic compensation cant be done to increase CO thus CO remains decreased
This uncompensated decreased SVR could lead to reduced pul vascular resistance and reduced venous return --> reduced preload ???
Is this concept correct?
If so, decrease in preload and CO are all due to failure of compensation on reduced TPR. . .
This uncompensated decreased SVR could lead to reduced pul vascular resistance and reduced venous return --> reduced preload ???
Is this concept correct?
If so, decrease in preload and CO are all due to failure of compensation on reduced TPR. . .
I do not think that the fall in CO is all due to failure to compensate for reduced TPR.
CO: HR X SV.
in neurogenic shock, there is a loss of sympathetic outflow (if the lesion is above L1). As a result:
HR decreases (bradycardia) because of a reduced sympathetic drive and an unopposed parasympathetic outflow (via intact vagal nerves) to SA nodes
SV decreases; as you have correctly pointed out, there is a reduction in venous return because of peripheral vasodilation and blood pooling away from the heart
Thank you. I missed to think about the reduced HR due to loss of sympathetic control in neurogenic shock
I got it.
