assignment Flashcards
definition of shock
shock is defined as ACUTE failure of circulatory system which results in hypoxia
-organs and tissues of body are not being supplied with adequate amount of blood
definition of HYPOVOLEMIC shock
specific to HEART
-significant decrease in blood or plasma volume that vascular compartments of heart do not fill therefore CO DECREASES
LOSS OF whole blood, plasma, extracellular fluid
when does hypovolemic shock occur?
when there is an ACUTE loss of 20% of circulating blood
caused by EXTERNAL trauma (like a severe burn)
or INTERNAL trauma (like haemorrhaging)
pathophysiology of hypovolemic shock?
-BLOOD LOSS–> amount of blood pumped from LV decreases (stroke volume decreased)—> arterial pressure is maintained because of norepinephrine released from SNS—>CO decreases because of SV decreased
compensatory mechanisms of hypovolemic shock (most immediate)?
most immediate compensatory mechanisms are sympathetic mediated response and renin!
- work to maintain CO and BP
- sympathetic outflow activates both alpha and beta receptors!
mechanisms to maintain CV function?
- contractility and rate of heart INCREASE
- vasoconstriction occurs to keep BP up and pump blood (SNS stimulation)
mechanisms to maintain blood volume?
RAAS- ADH and aldosterone released
LIVER constricts its veins and sinusoids to mobilize blood stored in liver into circulation
manifestations of hypovolemic shock?
loss of blood= THIRST increased HR SKIN= COOL decreased in arterial BP decreased urine output
treatment of hypovolemic shock?
treatment directed at RESTORING organ and tissue perfusions as well as vascular blood volume
-O2 administration
meds, fluids, blood IV
vasoactive meds only when volume deficits corrected but hypotension remains (acts to constrict or dilate BVs)
goal of hypovolemic treatment
RESTORE vascular volume
cardiac output and arterial pressure fail to 0 when..
approx 35-45% of total blood volume has been removed
