Shock and Resuscitation Flashcards
what is shock?
– Inadequate oxygen delivery to the tissues
– A condition of severe hemodynamic & metabolic dysfunction characterized by reduced tissue perfusion, impaired oxygen delivery & inadequate cellular energy production
is shock a disease?
no its a syndrome associated with many disease conditions
will you always see increased HR in cats that are in shock?
not always, they suck at compensating
what are some clinical signs of shock? (10)
- Reduced level of mentation
- Hypothermia / Cool extremities
- Tachycardia (bradycardia in cats)
- Increased respiratory rate & effort
- Poor peripheral pulses
- Decreased blood pressure
- Pale mucous membranes
- Prolonged capillary refill time
- Decreased urine production
- Decreased GI blood flow/ GI ulceration
what are some aspects of shock that are specific to cats?
- Bradycardia (HR < 160 bpm)
- Hypothermia
- Hypotension; Hypothermia decreases ability to cope with fluid load, Begin resuscitation but do not ‘blast’ a cat with fluids until you determine their response to rewarming
what is the physiologic response to shock and what does it lead to an increase in?
– Increased sympathetic output; Epinephrine (adrenaline) & NE released from adrenal glands
Increase in:
– Heart rate
– Cardiac contractility
– Vasoconstriction
what are three endocrine responses to shock
- Epinephrine & norepinephrine
– Released from adrenal glands & vasomotor endplates
– Immediate response - Antidiuretic hormone
– Released from the pituitary
– To conserve water
– Response within minutes - Renin–Angiotensin–Aldosterone (RAAS) system
– At the level of the kidneys
– Stimulated to conserve Na+ & water
– Response within hours
how is vasoconstriction organ selective (3)
– Affects organs with large numbers of a–adrenoreceptors; Skin, Skeletal mm, splanchnic organs, kidneys
– Perfusion maintained to; Carotid, coronary & hepatic arteries
– Allows preservation of blood flow to vital organs, but can result in ischemia of less vital tissues (Ie. Renal ischemia / failure)
what are the 3 stages of shock and what defines them?
- Early compensatory shock
– Physiologic responses maintain blood pressure - Early decompensatory shock
– Associated with clinical signs of shock - Decompensatory / terminal shock
– Irreversible shock
what are the clinical signs of early compensatory shock? what is the key sign?
- Clinical signs: Tachycardia, normal or elevated BP, normal or increased pulses, hyperemic mm, CRT< 1 sec
-heart rate is key
for early compensatory shock; what is happening by the patient? is it easy to diagnose? what is it a result of? what is the outcome?
- Appropriate cardiovascular compensation
- Easily missed, animal essentially normal
- Result of baroreceptor mediated release of catecholamines; successful increase in CO
- Good response noted to volume replacement, good outcome
what is the second stage of shock
early decompensatory shock
early decompensatory shock; what happens to blood flow, what are the clinical signs, what is the prognosis
- Redistribution of blood flow:
– decreased blood flow to the kidneys, gut, skin & muscles - Clinical signs:
– Tachycardia, tachypnea, poor peripheral pulses, hypotension, prolonged CRT, pale mm, hypothermia, depressed mentation - Prognosis
– Fair to good with immediate intervention
what is tiring in the second stage of shock
compensatory mechanisms
what stage is late decompensatory shock
terminal shock
can a patient suffer from more thn one category of shock
yerrrrr
late decompensatory shock; clinical signs, is it reversible, what damage has been done
- Clinical signs:
– Slowed heart rate (relative), pale cyanotic mm, absent CRT, weak / absent pulses, severe hypotension,
hypothermia, mentally unresponsive / coma, no urine production - Generally irreversible
– Not responsive to aggressive fluid resuscitation - Damage has overwhelmed the body’s natural protective mechanisms; Multiple organ dysfunction / failure
what is exhausted in late decompensatory shock
compensatory mechanisms
4 categories to classify shock
- Hypovolemic
- Obstructive
- Distributive = vasodilatory = hyperdynamic
- Cardiogenic
what is cardiogenic shock?
- Inadequate ventricular pump function
- Inadequate delivery of oxygenated blood to vital organs->Hypoperfusion
what can cardiogenic shock be due due?
May be due to:
– Myocardial failure (ie. Cardiomyopathy)
– Valvular dysfunction (ie. Severe mitral valve disease)
– Arrhythmias
what is hypovolemic shock? what happens regarding blood volume?
- Profound decrease in intravascular (blood) volume
– Loss of ≥ 30-40% of circulating blood volume OR 10-15% dehydration - Inadequate blood volume to deliver to vital organs -> Hypoperfusion
phase 1 of hemorrhage; what shifts? time range, what is attempted, what else adjusts
Phase 1 = Interstitial fluid shifts
– Within 1 hour
– Attempt to restore intravascular volume & organ perfusion
– Fluid shift dilutes; Red cell mass (PCV), Total solids (TS)
– Splenic contracture in the dog & horse; Spleen can sequester up to 30% of the RBCs
etiology of hypovolemic shock (2)
- Blood loss / hemorrhage
* External
* Internal - Dehydration
* Polyuria
* GI loss
* Burns
* 3rd space losses (eg. ascites)