Exam 2 - Shock and Fluid Therapy Flashcards
What is shock?
Inadequate cellular energy production due to low blood flow and low blood pressure
What does shock most commonly occur secondary to?
Poor tissue perfusion from low blood flow and critical decrease in oxygen delivery
What are the types of shock?
compensated and uncompensated
What is compensated shock?
Compensatory mechanisms maintain the viability organisms in the state of shock
What is uncompensated shock?
The compensatory mechanisms fail to perfuse vital tissue resulting in progressive circulatory collapse, disruption of the metabolic pathways, and death
What clinical signs are associated with compensated shock?
Pale mucous membranes, poor pulse quality, cold extremities, tachycardia, and normal blood pressure
What clinical signs are associated with decompensated shock?
Grey mucous membranes, bradycardia, hypotension, and altered mentation
True or False: Cats do not always display classic signs of shock
True
What signs may present in cats in early stages of shock?
bradycardia, hypothermia, and hypotension
What are the classifications of shock?
hypovolemic, distributive, and cardiogenic
What is hypovolemic shock?
when there is a loss of intravascular volume
What is distributive shock?
when there is maldistribution of vascular volume
What is cardiogenic shock?
when there is failure of the cardiac pump
What clinical findings are associated with hypovolemic shock?
Internal or external blood loss
Increased vascular permeability - infection, toxins, and immune reactions
Excessive loss of other body fluids due to vomiting, diarrhea, polyuria, and burns
Decreased CO due to diminished venous return
Triggers compensatory mechanisms to try and increase blood volume
What compensatory mechanisms are there to try and increase blood volume?
Vasoconstriction, increased cardiac contractility, and tachycardia
What are some examples of causes of hypovolemic shock?
Hemorrhage, severe dehydration, trauma, and infections
What amount of blood loss is associated with hemorrhagic hypovolemic shock?
1/4 to 1/3 blood volume loss
What can cause severe dehydration hypovolemic shock?
water deprivation, vomiting, and diarrhea
What infections can lead to hypovolemic shock?
EVA, Ebola, African swine fever
What clinical findings are associated with distributive shock?
Vasogenic shock (widening vessels), severe decrease in peripheral vascular resistance, pooling of blood in the venous system, and decreased venous return to the heart
Think hypotension to the extreme - blood just kind of sits where it is
What are some examples of distributive shock?
Septic shock, endotoxin, systemic inflammatory response syndrome (SIRS), anaphylaxis, and obstruction
What obstructive disorders can lead to distributive shock?
Heartworm disease and saddle thrombosis
What clinical findings are associated with cardiogenic shock?
Insults that negatively affect cardiac output
Can affect heart rate or contractility
What are some examples of cardiogenic shock?
Myocardial degeneration, cardiac tamponade, congestive heart failure, cardiac arrhythmias, drug overdose, and electrolyte imbalances
What can cause myocardial degeneration that results in cardiogenic shock?
Vitamin E/selenium, monensin, and infarcts
What drug overdoses can lead to cardiogenic shock?
anesthetics, beta blockers, and Ca+ channel blockers
What electrolyte imbalances can lead to cardiogenic shock?
hyperkalemia
What are some consequences of shock?
Insufficient oxygen cells Anoxic injury to endothelial cells Metabolic acidosis Myocyte damage Lesions Severe organ congestion Systemic response Multiple organ dysfunction Death
Why can anoxic injury as the result of shock be bad?
There is increased vascular permeability and loss of intravascular fluid
Why can metabolic acidosis as the result of shock be bad?
Insufficient renal and muscle perfusion
Suppresses cardiac output
Why can mycoyte damage as the result of shock be bad?
Insufficient perfusion and decreased cardiac output
What are the goals of compensatory mechanisms during shock?
Shunts blood to the brain, heart, and kidneys
Mobilize fluid from interstitial to intravascular space
Activation of sympathetic nervous system
Activation of the renin-angiotensin-aldosterone system (RAAS)
Release of ADH
What does activation of the sympathetic nervous system in the face of shock do?
Epi/norepi are released and cause tachycardia, vasoconstriction, and retention of sodium and water
What does the activation of the renin-angiotensin-aldosterone system (RAAS) in the face of shock do?
Vasoconstriction and retention of Na and water
What does release of ADH in the face of shock do?
promotes vasoconstriction
What lesions are associated with shock?
Initiating causes (hemorrhage, burn, tamponade, etc.), edema and pooling of blood, and degenerative changes in tissues from anoxia
Where does severe organ congestion occur in states of shock?
liver, GI tract, kidneys, and adrenals
What systemic response is associated with shock (this is bad)?
generalized cardiovascular collapse
What organ system is typically affected in dogs during shock?
GI tract
What organ system is typically affected in cats with shock?
lungs
What organ system is typically affected in horses with shock?
Large colon
What main diagnostics do you want to do for a patient in shock?
Blood gas analysis, lactate, CBC, chemistry, coagulation panel, and urinalysis
What additional diagnostics can be done for patients in shock?
Radiographs, US, echo, ECH, BP, and pulse ox
What is the goal of treatment in shock patients?
To give large volumes of fluids to restore effective circulating volume and tissue perfusion
How do you want to treat patients with hypovolemic shock?
IV fluids
How do you want to treat patients with cardiogenic shock?
Furosemide - be careful with IV fluids
How do you want to treat patients with distributive shock?
IV fluids
What ‘tools’ are recommended for treatment of shock?
Large bore catheters, vasopressors, antimicrobials if needed, and analgesia
True or False: Steroids are not recommended in patients with shock.
true
What percentage of total body water does intracellular fluid make up? Extracellular fluid?
Intracellular - 66%
Extracellular 33%
What are the components of extracellular fluid?
Plasma/intravascular (25%) and Interstitial (75%)
Define hypovolemia based on where the water loss is.
Lack of fluid in the intravascular component
Define dehydration based on where the water loss is.
Lack of fluid in the interstitial compartment
At what percentage of water loss do clinical changes occur?
> 10%
At what percentage of water loss is dehydration minimally detected?
5%
How can you address hydration status?
Skin tent, heart rate, pulse strength, limb temperature, weakness, capillary refill time, mucous membrane color, and blood pressure
What will you find on PE in a patient with 5% dehydration?
Tacky mucous membranes
What will you find on PE in a patient with 8% dehydration?
Dry mucous membranes and decreased skin turgor
What will you find on PE in a patient with 10% dehydration?
Retracted globes, persistent skin tent, and hypovolemia present
What will you find on PE in a patient with 10-12% dehydration?
Hypovolemic shock and eventual death
How can fluids be given for fluid therapy?
Parenteral and enteral
What are the forms of parenteral fluids?
Intravenous (IV), intraosseous (IO), and subcutaneous (SC)
What is daily fluid therapy calculated based on?
dehydration, maintenance, and ongoing losses
How is the fluid deficit calculated?
BW (kg) x (% dehydration/100) = fluid deficit (L)
Over what period of time should dehydration be corrected?
over 24-48 hours
What type of fluids are crystalloids?
isotonic fluids meaning their osmolarity/sodium concentration is similar to plasma
Why can giving crystalloids be bad (referring to absorption)?
they are made up of small solutes so in 20-30 minutes, 60-80% is out of the intravascular space
If you choose to give crystalloids rapidly, at what blood volume can you give for a dog?
90 ml/kg
If you choose to give crystalloids rapidly, at what blood volume can you give for a cat?
40-60 ml/kg
What is hypotensive resuscitation?
Keeping the patient dehydrated and at a MAP of 60 mmHg so that you can control hemorrhage before aggressive fluid therapy
What are the most common fluids we use in veterinary medicine?
LRSm Normosol R, 0.9% sodium chloride, and plasma-lyte
What types of fluid are colloids?
hyperoncotic - made up of large molecules
What about absorption is different between colloids and crystalloids?
Colloids pull fluid into the intravascular space and there is a greater increase in blood volume than infused volume
What colloids do we use in vet med and at what ‘dose’?
Hetastarch, Vetstarch
10-20 ml/kg
What do you need to follow up use of colloids with?
crystalloids because if you just use colloids you will end up dehydrating the patient
What is the ‘dose’ of colloids in cats?
5-10 ml/kg
What does hypertonic saline cause when you give it to a patient?
It will cause a transient osmotic shift from extravascular to intravascular compartments
At what ‘dose’ is hypertonic saline given?
5 ml/kg
What does hypertonic saline do in a patient when it is given?
It decreases endothelial swelling, modulates inflammation, increases cardiac contractility
What must you follow the administration of hypertonic saline with?
crystalloids because using them alone can lead to dehydration
What blood products can be given as fluid therapy?
Whole blood and fresh frozen plasma
Is administered over 1-2 hours
What are hemoglobin based oxygen carrying solutions, or oxyglobin, used for?
To deliver oxygen to patients - they contain hemoglobin
