Fluid Therapy Flashcards
What percent of body weight is water
60%
Pediatric: maybe 70%
Obese: use lean body weight for calculations (lean body weight is 70% of BW)
In dogs and cats, what percent of total body water is intracellular vs extracellular
Intracellular: 2/3 of TBW (40% BW)
Extracellular water: 1/3 of TBW (20% BW)
within this, interstitial water is 75% of ECF and intravascular water is 25% of ECF
Extracellular water is approx 1/3 of total body water (or 20% of body weight), what are its further subdivisions
Interstitial water: 75% of ECF
Intravascular water: 25% of ECF
2/3 of the total body water is _____________ (40% of body weight)
intracellular fluid
1/3 of the total body water is ____________ (20% of body weight)
extracellular fluid
If you have a 10kg dog. What is:
-TBW
-Intracellular fluid water
-Extracellular fluid water
-Interstitial Fluid Water
-Intravascular fluid
TBW: 0.6 x 10= 6kg
Intracellular: 2/3 of 6 L= 4L
Extracellular: 1/3 of 6L = 2L
Interstitial: 3/4 of ECF= 1.5L
Intravascular= 1/4 of ECF = 0.5L (1/12 of TBW)
About what percent of the body weight is blood volume
8-9% of BW in dogs
5-6% of BW in cats
Intravascular fluid water volume is about 5% of the body weight, why is the blood volume 8-9% of TBW and 5-6% of the body weight in cats?
Because blood contains both a liquid phase (plasma) and a cellular phase (RBC)
-IV water volume takes only the liquid phase into acocunt
If you have a 30kg dog. What is:
-TBW
-Intracellular fluid water
-Extracellular fluid water
-Interstitial Fluid Water
-Intravascular fluid
TBW= 0.6xBW= 18L
ICF: 0.67xTBW= 12L
ECF: 0.33xTBW= 6L
Intravenous Water (plasma) volume= 0.25xECF = 0.25x 6= 1.5L
Interstitial fluid volume= 0.75xECF= 0.75x6=4.5L
If you have a 5kg cat. What is:
-TBW
-Intracellular fluid water
-Extracellular fluid water
-Interstitial Fluid Water
-Intravascular fluid
TBW= 0.6xBW= 3L
ICF: 0.67xTBW= 2L
ECF: 0.33xTBW= 1L
Intravenous Water (plasma) volume= 0.25xECF = 0.25x 1= 0.250L
Interstitial fluid volume= 0.75xECF= 0.75x1=0.750L
Barrier between ICF and ECF compartments
Semi-permeable cell membrane
Freely permeable to water based on concentration gradients
Impermeable to electrolytes and proteins unless by transport
*Fluid move because of osmotic forces
How is fluid moved between ICF and ECF
Fluid move because of osmotic forces
Semi-permeable cell membrane
Freely permeable to water based on concentration gradients
Impermeable to electrolytes and proteins unless by transport
How is fluid moved within the ECF- between Int and IV
*Fluid moved because of Starling forces
-Endothelium
-freely permeable to electrolytes based on concentration gradients- water will follow
-relatively impermeable to proteins, larger molecules
Osmolality is proportional to
the number of non dissociable ions in a given solution
-not a function of the size or the molecular weight of the ion, just the number
expressed as mOsm/kg
How do you calculate osmolarity
2(NA +K) + BUN (mg/dL)/2.8 + Glucose (mg/dL)/18
Normal values are 280-305mOsm/L for dogs and 95-320 mOsm/L for cats
Is potassium higher ICF or ECF
ICF
Is Na+ higher ICF or ECF
ECF
Is Mg2++ higher ICF or ECF
ICF
Is Cl- higher ICF or ECF
ECF
What allows for movement of K+ out of cell and Na+ into the cell
Na/K ATPase
Effective osmoles
generate osmotic pressure across a semi-permeable membrane that is not permeable to that particle
*will result in movement of water
*Determines the tonicity of that compartment
ex: Sodium, Potassium
Why does albumin have minimal effect on osmolality
because its molecular weight is very high (66,000 Da) which makes the particle number relatively low
*We use colloid osmotic pressure, also known as oncotic pressure, refers to the osmolality due to proteins
Ineffective osmoles
have osmotic potential but they are unable to diffuse across the barrier
No osmotic pressure is generated, no movement of water
contributes to total osmolality but not tonicity
ex: Urea (diffusible), glucose (metabolized)
Note: D5W is iso-osmolar AND hypotonic
What are Starling’s forces
determine the movement of water between the interstitial fluid compartment and the intravascular fluid compartment, within the ECF
1) Oncotic pressure
2) Hydrostatic pressure
3) Vascular permeability
4) Lymphatic drainage
The movement of fluid within the ECF depends on
1) Oncotic pressure
2) Hydrostatic pressure
3) Vascular permeability
(Starling forces)
What does hydrostatic pressure fluid movement depend on
The pressure difference between the capillary and the interstitial
causes fluid leakage out of the vessel
Capillary Hydrostatic pressure: primarily the venous pressure (Arterial pressure is not translated across the precapillary sphincter)
venous stasis will increase the capillary pressure
Intersitium hydrostatic pressure: characteristic of the tissue, tightness of the interstitial matrix
Venous stasis will ______________ the capillary pressure
increase
Changes in hydrostatic pressure causes
fluid leakage out of the vessel
What does oncotic pressure fluid movement depend on
the oncotic pressure difference between the capillaries and interstitisal
*Causes fluid to go into the vessels (Keeps fluids into the vessels)
Oncotic pressure depends on
proteins- number of particles = concentration/molecular weight
Differences in oncotic pressure causes fluid to ____________
go into the vessels
What is the normal capillary oncotic pressure
Dog: 21-25 mmHg
Cat: 23-28 mmHg
What does the filtration coefficient (Kfc) depend on
1) Capillary surface area: larger surface area will increase Kfc
2) Hydraulic conductivity (leakiness of the vessels)- characteristics of endothelium and endothelial continuity
*Liver and kidney have leaky vessels: large net movement of fluid out of blood vessels
*Brain and muscle have relatively tight vessels
What is the reflection coefficient
relatively permeability of the capillary bed to protein (reflection = bouncing back of the protein)
depends on tissue (low in liver, high in kidney)
Lungs have low Kfc and high reflection coefficient (non leaky)
Lungs have low Kfc and high reflection coefficient. What does that mean
they are relatively non-leaky
Changes in osmolality moves water between
ECF and ICF
glycocalynx
dense, gel-like meshwork that surrounds the cell, constituting a physical barrier for any object to enter the cell
difference in the oncotic pressures on each sides is what drives the movement of fluids
What are the different kinds of crystalloids
1) Hypotonic :D5W, 0.45% NaCl
2) Isotonic: LRS, 0.9% NaCl
3) Hypertonic (7.2% NaCl)
What are the different kinds of colloids
1) Synthetic (Hetastarch, Vetstarch)
2) Natural (e.g Plasma)
What are the different kinds of blood products
1) Fresh Whole Blood
2) Packed Red Blood Cells
3) Plasma Products
4) Platelet Products
Fluid shifts between the intersititium and IV compartments because of
Starling’s forces
1) Oncotic pressure
2) Hydrostatic pressure
3) Vascular permeability
4) Lymphatic drainage
What is the osmolality of hypotonic crystalloids
0.45% NaCl = 154 mOsm/L
What is the osmolality of isotonic crystalloids
0.9% NaCl = 310 mOsm/L
What is the osmolality of hypertonic crystalloids
7.5% NaCl = 1300 mOsm/L
Crystalloids can be classified on osmolality but how else can they be divided?
Based on electrolyte composition and acid base effects
-NaCl based vs balanced electrolyte (LRS or Plasmalyte)
-The amount and type of bicarbonate precursors
ex: 0.9% NaCl has none and is therefore an acidifying solution
ex: LactaTe (LRS) or lguconate/acetate (Plasmalyte) are alkalinizing solutions
What are examples of alkalizing solutions
LRS (Lactate is the bicarb precursor)
Plasmalyte/ Normosol R both have Acetate gluconate as their bicarb precursors
What is D5W
it behaves like water
No electrolytes or bicarb precursors
same osm of water (~287)
What do hypotonic crystalloids behave
it is distributed in both the ICF and ECF compartments
volume of distribution depends on the amount of Na in the solution
sometimes easier to consider hypotonic cyrstalloids as isontonic + water
-Isotonic fluid distribute 100% in ECF compartment
Water distributes 67% ICF and 33% ECF
How does isotonic fluid distribute when given
100% in the ECF compartment
You have 1000mL of Dextrose 5% in water. How is it distributed
D5W is iso-isomolar and hypotonic solution as dextrose is not an effective osmole (metabolized readilyy)
Should be consider equal to 1000mL of free water
so
ICF: 67% of 1000mL = 670mL
ECF: 33% of 1000mL = 330mL
You have 1000mL of 0.45% NaCl. How is it distributed?
is equal to 500mL of water + 500mL 0.9% NaCl
so
ECF distribution= 500mL + 33% of 500= 500+ 165= 665mL
ICF distribution= 67% of 500mL= 335mL
When should you use hypotonic crystalloids
1) True “maintenance” fluids
2) Free water deficit (ie. hypernatremia)
3) Maintenance fluid when Na restricted is needed (e.g heart and renal disease)
When are hypotonic crystalloids indicated
1) IV compartment volume expansion (ie shock treatment) - not good at going to the vasculature
2) Free water gain (hyponatremia)
What are the side effects of giving hypotonic crystalloids
1) Hyponatremia
2) If administered rapidly causes acute changes in blood osmolarity and fluid shifts
3) Resulting in neurological sequels and RBC damage
What are the most commonly used IV solutions
Isotonic crystalloids
-LRS
-Plasmayte 148, Plasmalyte A, Normosol R
-Normal/physiologic saline (0.9% NaCl)
What is the fluid behavior of isotonic crystalloids
*Stays within the ECF (3/4 intersititium space, 1/4 in intravascular space)
*Doesnt go into ICF
Redistribution to interstitial within 20-30 minutes according to Starling’s forces
T/F: isotonic crystalloids do not go into the ICF
true
*Stays within the ECF (3/4 intersititium space, 1/4 in intravascular space)
What are the indications for using Isotonic crystalloids
1) IV volume expansion (ie. treatment of shock)
2) ECF volume expansion (ie. rehydration, treatment of dehydration)
3) Replacement of ongoing loses
What are the contra-indications to using isotonic crystalloids
1) Low oncotic pressure
2) Severe cardiac or renal disease
3) Severe, active bleeding (large volume contraindicated)
4) Free water loss or gain (sodium disturbances)
What are the side effects of giving isotonic crystalloids
-Possible tissue edema (if aggressive/large volume) bc it goes into interstitial
-Possible worsening or creation of acid-base disorders
-Pro-inflammatory effects
How do hypertonic crystalloids behave
causes a shift of fluid from ICF/interstitium into the IV compartment
*Rapid volume expansion (5-7x the volume given)
But rapidly redistribute across all compartments (10-30min) - only transient impact on IV volume expansion
Also have microcirculation effects and improved cardiac contractility
horses: give smaller volumes
What are the indications for using hypertonic crystalloids
1) IV volume resuscitation (ie. shock treatment)
2) Traumatic brain injury- sucks water out of the brain
3) Correction of acute hyponatremia (usually use 3% NaCl)
What are the contra-indications for using hypertonic crystalloids
1) Chronic hyponatremia
2) Severe dehydration
What are the side effects of hypertonic crystalloids
1) Only transient volume expansion for 20-30 min
2) Cannot be re-dosed
3) Causes transient hypernatremia
4) Reflect vasodilation and bradycardia if bolused too fast
How do colloids behave
they contain larger molecules which do not readily cross capillary membranes
volume stays in the vascular space
contribute to oncotic pressure
How does hydroxyethyl starch (HES) behave
it is a synthetic colloid, modified polymers of amylopectin
volume of distribution is vascular space
volume expansion power of 80-120%
prolonged vascular expansion time compared to crystalloids
When should you give synthetic colloids like (HES, VES, Dextrans, Gelatin, HBOC)
1) IV fluid resuscitation (ie shock)- especially in cases with low albumin or transient response to isotonic crystalloids
2) Oncotic support for hypoproteinemia
What are the side effects or contraindications behind using synthetic colloids like (HES, VES, Dextrans, Gelatin, HBOC)
1) Coagulopathy: dose dependent (more than 20ml/kg/day with HES) but lower MW colloids like VetStarch is less concerning
mostly due to impaired platelet function
2) Renal injury: concern for increased risk of AKI and kidney failure in critically ill patients (lack of evidence in pets , just humans)
How might synthetic colloids like (HES, VES, Dextrans, Gelatin, HBOC) cause coagulopathies
mostly due to impaired platelet function
*VetStarch is less concerning than HES
What is the fluid behavior when giving natural colloids (plasma)
usually thought to expand vascular volume equivalent to the amount given (100%)
What are the indications for using natural colloids, like plasma
1) Acute blood loss
2) Coagulopathy
3) Hypoalbuminemia
What are the adverse effects of natural colloids
1) Cost
2) Low Availability
3) Transfusion reactions (less than 1%)
What is the fluid behavior of human serum albumin
stays in the vasculature AND pulls fluids from intersitium and ICF (VEP >100%)
What are the side effects of Human Serum Albumin
1) Acute (type I) and delayed (type III) hypersensitivity
2)redosing is absolutely contra-indicated and will trigger anaphylactic shock
3) In people, no documented benefit, except maybe in septic shock
What are the indications for human serum albumin
There really arent, it is a strong debate but possible severe sepsis and septic shock (hypoalbuminemia with severe side effects)
most patients it is contra-indicated, if previously received HSA especially
What are the pros/ cons of the oral/enteral route
Pros:
Most natural way, low cost and risks, can also provide nutritional/calric support, either spontanteous drinking or through feeding tube, much less risk of volume overload
Cons: usually patients needed fluid therapy were not able to maintain volume status to begin with because of sickness, need functional GI tract, volume and speed of administration is usually too high for correction of dehydration and/or hypovolemia
What are the complications of the oral/ enteral route
low effeciveness for fluid expansion
Risk of aspiration pneumonia if vomitting and/or low LOC
What are the advantages of IV route
1) Direct vascular access for volume expansion
2) Rapid administration is possible- cut down placement if needed
3) Multiple types of fluid can be given (all types of cyrstalloids, colloids, blood products)
used for IV fluid resuscitation, significant dehydration (especially with expected ongoing losses), critically ill patients
What are the indications for using IV route for fluids
used for IV fluid resuscitation, significant dehydration (especially with expected ongoing losses), critically ill patients
What are the peripheral IV locations that you can use
Cephalic
Medial saphenous in dogs
Lateral saphenous in cats
What are the central IV locations that you can use
Usually on the jugular vein
usually longer and with multi-lumen
can be peripherally inserted central catheter (PICC) in the lateral or medial spahenous
What are the differences between administering peripheral vs central vein IV
Peripheral: fast, easy cheap and the bigger and shorter catheters allows for a faster administration because the flow of the fluid is proportional to the radius of the tube but only for relatively isotonic fluid and is easy to dislodge and cant be used for sampling
Central: Safer admin of hypo- and hypertonic fluids, serial blood sampling but requires more expertise and shouldnt be used for TBI or high risk bleeding patients
Can peripheral or central venous be used for serial sampling
Central venous
Can peripheral or central venous be used for isotonic solutions
peripheral venous
When might the intraosseus route be used
1) Smaller patients (ie neonates_
2) Exotics such as birds or others
3) rapid access if IV access is not possible or challenging (ie shick, CPR)
4) Various sites: proximal humerus, femur or tibia; birds: distal ulnar and proximal tibia
What are possible complications of IV catherization
1) Infection/Inflammation- thrombophlebitis or catheter side inflammation/ infection
2) Thrombosis/ thromboembolism- clot formation with potential migration
3) Extravasation of fluids from catheter can cause severe necrosis
4) Blood loss if disconnected
5) Blood stream related infection (BSRI)
6) Cathetic fragment foregin body
What are the pros and cons of the intraosseus route?
Pros: rapid access to vascular space when IV not possible or challenging, drugs and fluids can be given equivalent to IV, relatively easy placement
Cons: often short-lived access, complications are not uncommon- infection (osteomyelitis), fracture, maybe technically challenging in very small patients
How are SQ fluids absorbed
fluid is administered in the intersitium (between shoulder blades) and will be gradually absorbed and distributed across fluid compartments according to Starling’s forces
-speed of distribution dependent on hydration status and peripheral perfusion
What kinds of fluids can be given through the SQ route
Only administer isotonic fluids, usually LRS
-Hypo/hypertonic solutions (ie D5W) can cause significant irritation/ and otissue injury
*some isotonic fluids like Plasmalyte may sting and should be avoided
T/F: you can give hypotonic solutions through SQ route
False
Hypo/hypertonic solutions (ie D5W) can cause significant irritation/ and otissue injury
What are the indications to giving SQ fluids
1) Mild dehydration
2) patient cannot be hospitalized
What are the advantages to giving Sq fluids
1) inexpensive
2) easy technically
3) Can be administered by owners as needed
What are the disadvantages of giving SQ fluids
1) Unreliable absorption
2) Limited volume so not for severe dehydration
3) Slow absorption so not for shock
4) Limited options for fluid administered (only isotonic)
What is the dose of most SQ fluids
Dose dependent of the room between the shoulder blades as well as appropriate rehydration volume (eg 5% of body weight)
What are the complications of SQ fluids
pain, irriation
pressure necrosis
excessive admin
hematoma
infection: SQ cellulitis, abscess formation
When you are talking about dehydration, what are you talking about
Loss of isotonic fluid (aka ECF- loss of water AND salt)
Dehydration is loss of
ECF - water and salt
What are the 5 physical examination signs of dehydration
1) Mucous membranes
2) Skin elasticity (turgor)
3) Position of eye in orbit
4) Changes in body weight
5) Volume status
6) + Thirst mechanism
How can you examine dehydration in a patient
Physical signs
1) Mucous membranes
2) Skin elasticity (turgor)
3) Position of eye in orbit
4) Changes in body weight
5) Volume status
6) + Thirst mechanism (behavior change)
Bloodwork: PCV/TP and BUN, creatinine
Urinalysis: specific gravity
When do signs of hypovolemia due to dehydration become evident
When the patient is severely dehydrated (10-12%)
How does the eye position change in due to dehydration
Mild dehydration (5-7%): normal position
Moderate dehydration (8-10%): may be sunken
Severe dehydration (10-12%): sunken eyes
How does skin elasticity change due to dehydration
Mild dehydration (5-7%): slightly decrease
Moderate dehydration (8-10%): decrease
Severe dehydration (10-12%): stands in a fold
What do the mucous membranes look like when a patient is dehydrated?
tacky
T?F: dehydration decreases tear and saliva production
true
What influences membrane moistness
1) Hydration staus
2) Evaporation (panting)
3) Tear production influenced by KCS “dry eye”
How does the skin elasticity test determine hydration status
there is less fluid in the interstitial space and there is a decrease in elasticity/ turgor leading to an increased time to return to a normal position
Elasticity of the skin depends on
hydration status - also used to assess overhydration
also age
young: increase skin elasticity
old: decrease skin elasticity
obese: increase skin elasticity
How do young animals influence the skin elasticity test
they have increased skin elasticity
How do old animals influence the skin elasticity test
they have decreased skin elasticity
How do obese animal influence the skin elasticity test
they have increased skin elasticity
What other factors influence the position of the eye in the orbit for dehydration assessment
1) Obesity
2) Ocular disease
3) Breed and conformation
What causes the eye to sink with dehydration
sunken eye is associated with reduced volume of retrobulbar fat
What is the best way to assess hydration status
changes in body weight
get historical background
-normal dogs- no access to water
-induce dehydration (diuretics)
-monitoring body weight and physical examination findings
furosemide depletes a patients
extracellular fluid compartment
A patient that is 10% dehydrated lost
10% of their body weight
ex: 10 kg dog that is 10% dehydrated lost one L of water
What 2 factors triggers the thirst sensation
1) Decrease in ECF (aka dehydration) triggers ADH release which triggers RAAS system and triggers thirst centers in the brain to search out and ingest water
2) Increase in osmolality of the extracellular space (ie an increase in the concentration of sodium)
Dehydration is loss of ___________ fluid while hypovolemia is loss of ____________ fluid
interstitial; intravascular
What percent dehydration causes shock
> 10% dehydration you have significant hypovolemia
-Loss of intravascular fluid
What is the difference between dehydration and hypovolemia
ex: 10 kg dog is 10% dehydrated and losts 10% of BW= 1kg=1L
Dehydration is loss of ECF compartment 3.4 from intersitium= 750ml and 1/4 from IV = 250ml
10% dehydration in a 10kg dog corresponds to a loss of 250mL from the intravenous compartment
if 10kg dog, 800mL is blood volume so they lost 31% of blood volume. you see signs of hypovolemia for a loss of 30% of blood voluleme
A 10kg dog is 10% dehydrated. How much IV volume is lost
10 kg dog is 10% dehydrated and losts 10% of BW= 1kg=1L
Dehydration is loss of ECF compartment 3.4 from intersitium= 750ml and 1/4 from IV = 250ml
10% dehydration in a 10kg dog corresponds to a loss of 250mL from the intravenous compartment
You will see the clinical signs associated with hypovolemia when ______________
greater than 30% of blood volume is lost / >10% dehydrated
T/F: the body can compensate to maintain vascular volume but cannot do the same for interstitium volume
True
How does dehydration affect BUN
it will increase it
Dehydration is loss of ___________ fluid so you should replace with _____________
loss of isotonic fluid; replace with isotonic crystalloid
What is the time frame for correcting dehydration
4-24 hours
(average is 8-12 hours)
depends on: severity, speed of loss, compensatory, species, comorbidities (heart, lungs, kidneys), age, practicality, monitoring abilities
What is the equation for maintenance (dogs and cats)
Dogs:
132 x BW(kg) ^0.75 or
(*) 70 x BW(kg)^0.75
-preferred
Cats:
70x BW(kg)^0.75
Generally, what are the fluids rate for maintenance in dog and cat
40-60mL/kg/day
or
2-4mL/kg/hr or 1-2mL/kg/hr
Big dog or cat= lower end
small dog= higher end
or
30 x BW(kg) + 70(ml/day)
After fluid maintenance, you want to do fluid replacement, what should you use
Isotonic crystalloid
-too much Na and too little K
-add potassium to the fluid bag
-kidneys will handle the sodium load
hypotenoic crystalloid or true maintenance fluid- Plasmalyte 56 or Normosol-M when renal function is compromised or if in heart failure; for large animals
How should you account for abnormal ongoing losses (vomiting, diarrhea, burns, etc)
weight the losses or just do 1/2 maintenance for a lot of diarrhea or 1x maintenance for a lot of diarrhea
How do you monitor ongoing losses
Re-assess the patient by blocks of 4-12 hours
-PE
-BW
-Fluid balance (input versus output)
-Quantitative: urine output if urinary catheter or amounts of food/water eaten/drunk
-Qualitative: hypersalivation, diarrhea
You are presented with a 3yo M/C Labrador retriever who has had diarrhea for the past 3 days. He got into the garbage the day before. Still drinking water. No hematochezia or melena.
T=101.3
P=108
R=30, mm pink
slightly tacky, CRT= 2sec
BW: 40kh
Skin tent is very mildly prolonged and the eyes are in their normal position in orbit. What is the amount of dehydration? What should you give for maintenance
Mild to moderate dehydration 5-8% (pick 6%)
Deficit = 40 x 0.06= 2.4 kg(L) lost
Fluid type: Isontonic crystalloid (LRS)
timeframe:
6hr = 400ml/hr
10 hours= 240ml/hr
Maintenance= 70x40^0.075= 1113mL/ day= 46mL/hr
Total= 446mL/hr for 6 hours or 286mL/hr for 10 hours
Shock is defined as
inadequate cellular energy production due to critical decrease in DO2 compared to O2 consumption VO2 in tissues
O2 need»»» O2 delivery
inadequate cellular energy production due to critical decrease in DO2 compared to O2 consumption (VO2) in tissues
O2 need»»» O2 delivery
shock
What is produced as a result of anaerobic respiration
Lactate
What are the results when there is a decrease in O2 delivery, seen in patients with shock
1) Anaerobic metabolism
2) Increased lactate production and decreased ATP production
3) Cell dysfunction and failure (pump dysfunction of NA-K ATPase leading to intracellular edema, leakage of intracellular contents extracellularly and inability to regulate intracelular pH)
4) Multi-organ dysfuction (MODS)
What is the result of pump dysfunction of Na-K ATPase during shock?
pump dysfunction of NA-K ATPase leading to intracellular edema, leakage of intracellular contents extracellularly and inability to regulate intracellular pH)
What could limit the delivery of O2 to tissues in dogs and cats?
1) Respiratory: hypoxemic
2) Heart: cardiogenic (Decreases in SV or HR)
3) Vessels: Hypoxemic- (Hemoglobin, SaO2, PaO2), Hypovolemic, Distributive
4) Organs/Cells: Metabolic
due a decrease in circulating blood volume
severe dehydration >10-12%
can be from GI losses (Parvovirus), excessive diuresis (AKI) or burn
or
Blood loss from trauma
Hypovolemic shock
Why might a patient be in Hypovolemic shock
due a decrease in circulating blood volume
severe dehydration >10-12%
can be from GI losses (Parvovirus), excessive diuresis (AKI) or burn
or
Blood loss from trauma
Why might a patient be in cardiogenic shock
shock due to decreased forward flow from the heart
1) Congesitve heart failure (Mitral valve disease, dilated/ hypertrophic cardiomyoapthy)
2) Cardiac arrhythmias (ventricular tachycardia, atrial fibrillation, bradyarrhythmia)
3) Cardiac tamponade (Obstructive shock)
4) Drug overdose- beta blockers, calcium channel blockers
How might a patient be in distributive shock
due to marked decrease or increase in systemic vascular resistance or maldistribution of blood
inadequate blood flow to organs, due to vasodilation- sepsis or anaphylaxis
obstruction of blood flow coming to heart or leaving heart
-Gastric dilation volvulus (GDV)
-Pulmonary thrombo-embolism (PTE), saddle thrombus
-heartworm disease, pericardial effusion
What is the result of obstruction of blood flow due to gastric dilation volvulus (GDV), PTE, saddle thrombus, heartworm disease, pericardial effusion?
Distributive shock
-due to marked decrease of increase in systemic vascular resistance or maldistribution of blood from the obstruction of blood flow from/away heart
How does sepsis lead to shock
vasodilation leading to inadequate blood flow to the organs (Distributive shock)
How does anaphylaxis lead to shock
vasodilation leading to inadequate blood flow to the organs (Distributive shock)
What are the different types of shock
1) Hypovolemic (decrease circulating blood volume from loss or dehydration- GI, diuresis, or burn)
2) Cardiogenic (decreased forward flow from CHF, arrhythmias, tamponade or drugs)
3) Distributive: inadequate blood flow from increased or decreased vascular resistance (sepsis, anaphlyaxis, GDV, PTE, HWI, pericardial effusion)
4) Hypoxemic shock: due to decreased O2 content in arterial blood from severe pulmonary disease, anemia, dyshemoglobinemia (CO toxicity, methmoglobinemia)
5) Metabolic shock: due to decrease in cellular metabolic machinery, hypoglycemia, cyanide toxicity, cytopathic hypoxia of sepsis
How does GDV lead to obstructie shock
there is compression of great vessel that decreases venous return and preload
How does cardiac tamponade lead to obstructive shock
there is compression of the heart leading to reduced diastolic filling
How does tension pneumothorax lead to obstructive shock
there is compression of the heart leading to reduced diastolic filling
What are potential causes of hypoxemic shock
due to decreased O2 content in arterial blood (CaO2= 1.34 x Hb x SaO2) + 0.0031 x PaO2)
1) Severe pulmonary disease
2) Low Hb: anemia
3) Dyshemoglobinemia: CO toxicity, methmoglobinemia
What are the potential causes of metabolic shock
due to decrease in metabolic machinery
1) Hypoglycemia
2) Cyanide toxicity
3) Cytopathic hypoxia of sepsis
What are the compensatory mechanisms for patients with shock
Goal to return to normal circulating volume and normal pressure
1) Increased sympathetic activity (EP/ NE) leading to Vasoconstriction (Increase HR and contractility)
2) Renin-Angiotensin- Aldosterone system activation + ADH release, leading to vasoconstriction-H20 and Na+ retention
3) Mobilization of fluid from interstitial to the intravascular space
What is the point of vasoconstriction as compensatory for patients with shock
Vasoconstriction under SNS activation leads to increase HR and contractility
Vasoconstriction under RAAS activation leads to H20 and NA2+ retention
What is the heart rate of patients with shock
Cats: HR <160 and HR >220 bpm
Dogs: HR >160 for small breed and >100 bpm for large breed
What are the pulse quality changes you will see in patients with shock
1) Pulse deficit
2) Bounding pulse: severe anemia and sepsis
3) Weak/Absent: femoral / metatarsal pulse- hypotension
4) Asymmetrical pulse: saddle thrombus of cats
What might you see with the CRT in patients with shock/ poor perfusion
> 2sec: vasoconstriction
<1s: vasodilation = sepsis
How might you have a patient in shock but their mucous membranes are injected
Sepsis, feber, pain, anxiety
Why might a patient in shock have white mucous membranes
anemia, poor peripheral perfusion (Vasoconstriction)
Why might a patient have brown mucous membranes
acetaminophen toxicity
How might a patient have yellow mucous membranes
liver disease
What will the mentation of a patient with shock be
dull and depressed
What are the 3 stages of shock *
1) Compensated Stage: Mild to moderate alteration in perfusion parameters, Mid increase in lactate, and normal blood pressure
2) Decompensated Stage: moderate to severe alteration in perfusion parameters, major increase in lactate, low blood pressure
3) Terminal Stage: Severe alteration in perfusion parameters, even more major increase in lactate
Low blood pressure
What is the goal of treating hypovolemic shock
to return to normal circulating volume + normal blood pressure
How might hypovolemic shock occur
1) Severe dehydration >10-12%
2) Hemorrhage (trauma)
What are the clinical signs of a dog with hypovolemic shock
Compensated
a) level of consciousness is normal to decreased
b) CRT is normal to increased
c) Tachycardia (Small >140-160 while large is >100 bpm
d) Blood pressure is WNL/ hypertension
e) Good peripheral pulse
f) +/- Increased respiratory rate
g) +/- cold extremities
Decompensated
a) level of consciousness is decreased
b) CRT is increased majorly, pale mucous memebranes
d) tachycardia/bradycardia
e) Hypotension: SBP <90mmHg
f) Weak peripheral pulse
g) Cold extremities
How does blood pressure change when a patient is in hypovolemic shock
at first there will be compensation to correct the blood pressure and it will be normal to hypertensive but then when it is decompensated, the patient will be hypotensive SBP <90 mmHg
What are the clinical signs of hypovolemic shock in cats
Lethargy, laterla recumbency
tachycardia (HR> 220bpm) / bradycardia (HR <140 bpm)
Pale mucous membranes
Weak pulses
Hypotension
Hypothermia
How do the clinical signs of dogs and cats in hypovolemic shock differ
cats dont really have the compensated/ decompensated shock they just come in with
Lethargy, laterla recumbency
tachycardia (HR> 220bpm) / bradycardia (HR <140 bpm)
Pale mucous membranes
Weak pulses
Hypotension
Hypothermia
What is the pathophysiology of sepsis
1) Gram - (LPS) and Gram + (cell wall components) are a stimuli fro host immune system that cause cytokine storm (TNFa, IL-1, IL-6, IL-8, IL-4, IL-10, IL-13…)
2) Massive release of NO leading to powerful vascular smooth muscle relaxant -> vasodilatory state
3) Disturbances in endothelium permeability and microcirculation abnormalities
What are the clinical signs of septic shock in dogs
Hyperdynamic phase: fever, tachycardia, CRT <1s. Hyperemic mucous membranes, bounding pulses, blood pressure within normal range
Hypodynamic phase: dull mentation, prolonged CRT, pale mucous membranes, tachycardia (bradycardia), weak peripheral pulse, hypotension (<90 mmHg)
What are the clinical signs of septic shock in cats
Lethargy, lateral recumbency
tachycardia (HR >220 bpm) / bradycardia (HR <140bpm)
pale mucous membranes
weak pulses
Hypotension
Hyperthermia/ normothermia
What are the bedside diagnostic tests for determining shock state (type)
1) Lactate, PCV/TP, blood glucose
2) Blood gas
3) Electrocardiogram
4) Pulse oximetry
5) Point of Care ultrasound (POCUS)
What is normal lactate levels
<2-2.5 mmol/L
2-2.5: indicates poor perfusion
slight 2-3
mild: 3-5
moderate: 5-8
marked: 8-10
severe >10 mmol/L
get serial values rather than single one
You have a patient with a blood glucose <65 mg/dL. What might be causes of the hypoglycemia
Sepsis!! might be cause of shock
Addisons Disease
Porto-systemic shunt
What does Increased PCV and TP tell you
dehydration
What does increased PCV with decreased TP tell you
acur blood loss
What does decreased PCV with normal to increase TP tell you
possible IMHA
What will you see on ECG of a patient with shock
1) Ventricular tachycardia,
2) supra-ventricular tachycardia
3) atrial fibrillation
*Helps dictating the treatment
Cyanosis occurs when
5g/dL of Hb is not oxygenated
SpO2 = 67%, PaO2= 37mmHg (for normal PCV)
Why might it be more tricky to evaluate blood pressure in cats
doppler tends to underevlauate systolic, reading closer to the mean arterial pressure
Hypotension <90mmHg
Normal BP >90mmHg
What is normal BP
> 90mmHg
What is the point of abdominal POCUS for determining the shock type
to identify peritoneal/ retroperitoneal free fluid
What position should an animal be in for abdominal POCUS for determining shock type
right lateral recumbency
What views should you look at for abdominal POCUS for determining shock type
1) Diaphragmaticohepatic
2) Splenorenal
3) Cystocolic
4) Hepatorenal
What is the goal of thoracic POCUS for determining shock type
pleural/ pericardial effusion, comet tails, size of the left atrium
What position are dogs in for thoracic POCUS
patient in standing or sternal position
What do comet tails tell you
Blines to indicate the presence of an alveolar- interstitial pathology
important to look at the overall distribution of the B lines throughout the lung parenchyma
What is normal LA/Ao ratio
Dogs: <1.3
Cats <1.6
Suspicious for CHF if
dogs >1.3
cats >1.6
Diagnostic for CHF is LA/Ao >2
What are the 7 steps of shock resuscitations
1) Fluid or not?
2) What route?
3) What type?
4) How mich?
5) How fast?
6) End points of resuscitation?
7) What if it does not work?
If you have a patient in shock. When should you give fluids? When should you not?
Yes: Hypovolemic and maldistributive
NO: Cardiogenic, anemic/ hypoxemic, metabolic
When should you NOT give fluids to a patient that is in shock
when it is cardiogenic, anemic, or hypoxemic caused
important to get history, physical exam (cardiac auscultation), and blood pressure first
only use fluids for hypovolemic or maldistributive
What is the best route to fix shock caused by hypovolemia or maldistributive
Intravenous first
if you cant- intraosseous
How do you deliver large volumes quickly, say to correct hypovolemic shock*
Think of Poiseuille’s law where flow depends on pressure, radius, and viscosity
1) Increase pressure (gravity, slam bags, or rapid delivery system)
2) Increase the radius of catheter (increases flow rate by power 4)
3) Decreasing the length of catheter (use short catheter)
4) Increasing the number of catheters
Note: more viscous fluids will be more difficult to push
How does the length of the catheter relate to the flow
inversely. the longer the slower flow
Why might you not use a fluid pump to fix a patient in hypovolemic shock
It maxes out at 1L/hour and you want to deliver it faster
What should you do if you want to deliver a large volume of fluids quickly to correct hypovolemic shock
Think of Poiseuille’s law where flow depends on pressure, radius, and viscosity
1) Increase pressure (gravity, slam bags, or rapid delivery system)
2) Increase the radius of catheter (increases flow rate by power 4)
3) Decreasing the length of catheter (use short catheter)
4) Increasing the number of catheters
Note: more viscous fluids will be more difficult to push
Why do you not want to give hypotonic fluid to correct hypovolemic shock
because most goes intracellularly and intertitial (extra), small amount goes IV
VEP=8.3%
ex: 100mL given- behaves like water: 2/3 goes intracellular, 1/3 goes into extracellular and only 25% of that goes into the vascular space
What is volume expansion power (VEP)
the amount of fluid in the vascular space at equilibrium
depends on individual fluid behavior in the body
What is the Volume Expansion power of Isotonic saline
It does not go into intracellular compartment
*All goes into extracellular but 3/4 goes into interstitial while 1/4 goes into IV
VEP= 25%
What is the volume expansion power of colloids
VEP= 100%
all goes into the IV
What is the volume expansion power of hypertonic saline (7-7.5% NaCl)
500%
water is pulled from the intracellular and interstitial space
Rank the following fluids (Colloids, Hypotonic, Isotonic, Hypertonic) by their Volume Expansion Power***
(Know this will be on test)
Hypotonic fluids: 8.3%
Isotonic fluids: 25%
Colloids: 80-120%
Hypertonic Saline: 500-700%
Rank the following fluids by their volume needed to be given for shock
Isotonic > Colloids > Hypertonic Saline
What is your fluid for first line for shock in small animal clinical practice
Isotonic crystalloid
-cheap, readily available, and rapidly eliminated
colloids take a long time to go away if you give too much
When do you not want to use isotonic crystalloids for shock
low albumin or COP
concerns about active bleeding (small volume is more appropriate)
High risk of volume overload when patient has heart murmur or lung disease
When do you want to use colloids for shock
1) small volume resuscitation
2) transient response to crystalloids
3) no response to crystalloids
4) Low albumin or COP
When do you not want to use colloids for shock
1) Coagulopathies
2) Renal failure
When should you use hypertonic saline for shock
1) Large animal (EQ, V< large dog)
2) traumatic brain injury
When should you not use hypertonic saline for shock
Severe hypernatremia or hyponatremia
What are the pros and cons of hypertonic saline
Pros: small volume, improves cardiac output, improves oxygen delivery to tissue
Cons: Can only give once (seizures because it makes brain cells smaller), hypernatremia, bradycardia and vasodilation if “flash bolus”
What are the shock doses of fluids for dogs **
It depends on VEP of fluid
Isotonic fluid: 80-100mL/kg
Colloids: 20mL/ kg
Hypertonic fluid: 5mL/kg
Blood products: 20ml/kg
*Give aliquot of shock dose- usually 25-33% depending on factors
What is a typical shock dose of isotonic fluid in a dog
80-100mL/kg
What is a typical shock dose of colloids in a dog
20ml/kg
What is a typical shock dose of hypertonic fluid in a dog
5ml/kg
What is a typical shock dose of blood products in a dog
20ml/kg
What are the typical shock doses in cats **
Isotonic fluid: 40-60ml/kg
Colloids: 10ml/kg
Hypertonic fluid: 3ml/kg
Blood products 10ml/kg
about half of what the dog is
Give aliquot of shock dose- usually 25-33% depending on factors
What is a typical shock dose of isotonic fluid in a cat
40-60ml/kg
What is a typical shock dose of colloids in a cat
10ml/kg
What is a typical shock dose of hypertonic fluid in a cat
3ml/kg
What is a typical shock dose of blood products in a cat
10ml/kg
When delivering a shock dose of fluids, you typically give an aliquot of ____________ of the dose but it depends on__________
25-33% of dose
depends on: severity, speed of loss, compensatory mechanisms, species, comobordities, age, practicality, monitoring abilities, cause of shock
How fast should you give fluids for shock
aliquot of the shock dose (25-33%) over a period of time
usually 5 to 30 minutes depending on:
severity, speed of loss, compensatory mechanisms, species, comobordities, age, practicality, monitoring abilities, cause of shock
T/F: you should always aliquot the shock dose
False- it is true you typically give 1/3 to 1/2 of the dose depending on factors but with hypertonic saline you need to give all of the dose over 5 minutes
When should you not give 1/2 to 1/3 of the shock fluid dose?
Hypertonic Saline
-Must be given over 5 minutes
-Redistribute in all compartments in 20-30 munutes
*If too fast= bradycardia/ vasodilation
*If too slow: loses the VEP
Needs to be followed boy another type of fluid (colloids or isotonic crystalloid but at 1/4 the dose
What happens in hypertonic saline is given too fast? What about too slow?
Too fast = bradycardia/ vasodilation
Too slow= loses the VEP
*Give over 5 minutes (ENTIRE DOSE)
What kind of horse cannot handle hypertonic saline
Foals (infants in general)
T/F: you should never use hypertonic saline in infants (foals, kittens, etc)
True
What is unique about giving blood products to correct shock
Most clinicians will use higher aliquots of volume as a shock dose (10-20ml/kg)
Can be given fast 5-30 minutes
if possible equal volume of plasma and red blood cells
If you give fluids to correct shock and it is not working, what should you do?
1) More fluids?
2) Positive inotropes (Dobutamine)
3) Vasopressors- Dopamine, Norepinephrine, Vasopressine
Permissive hypotension
when there is a patient that is hypotensive with an uncontrolled hemorrhage
you need to keep systolic blood pressure 80-90 until hemorrhage is controlled
*Not too low, not too high
What should you do if a patient is in septic shick
1) early fluid resuscitation (isotonic)
2) early use of a vasopressor (NE)
3) Early antimicrobial use
4) Find and control source of sepsis
*Use of artifical colloids is controversial
What should you do when managing patients with burns to correct fluid
1) Higher volume of crystalloids (evaporative losses)
2) Use of colloids or albumin products (because of protein loss
When do you use blood products for fluid resuscitation
Severe hypovolemic hemorrhagic shock
-more negative base excess
-higher lactate
-more severe shock (Higher HR, lower temp)
-Lower PCV and TP
-Higher Anumal trauam score
-Semi quantitative FAST 3 and 4
You have a 30kg dog HBC that is obtunded, HR 160, white mm, CRT 4sec, poor pulses and cold extremities. How do you correct this shock
Fluids IV
Isotonic (LRS or Plasmalyte)
80-100mL/kg
2400-3000mL is shock dose, start with 1000mL
a pump will only deliver at 999mL/hr, instead use 18G short IV catheter without any extension set or T port and placing the liter bag in a pressure bag constantly pumped 300mmHg, 1 liter can be delivered in 7 minutes
Shoot for 10-15 minutes for a reasonable achievable goal
What is the ROSE concept of fluid therapy for patients in shock
1) Resuscitation with fluids in order to stabilize the patient
2) Optimization of fluid therapy to support major organs, electrolyte status, acid base status, and other metabolic parameters such as oxygen delivery and lactic acidosis
3) Stabilization to provide continued support for the patient
4) Evacuation to minimize risk of volume overload and actively remove volume
early goal-directed fluid management using fluid boluses for patient rescue
resuscitation of fluid therapy
organ support and maintaining tissue perfusion using fluid boluses
optimization of fluid therapy
conservative fluid management for maintenance and replacement
stabilization of fluid therapy
late goal- directed fluid removal (de-resuscitation) to minimize risks of volume overload (generally weeks)
evacuation of fluid therapy
How long can an adult horse go without food?
2-3 weeks
lots of glycogen
(foals only for 6-12 hours)
Why might a large animal be in hypovolemic shock
1) Hypovolemia/ dehydration from GI disease, liver disease, renal disease, neurologic disease
2) Blood loss (around 8-10L loss)
Why might a large anumal be in distributive shock
1) Sepsis
2) Toxemia
3) Anaphylaxis
T/F: cardiogenic shock is uncommon in large animals
true- but treatment is focused on cardiac function and oxygen support
Why might you give fluids in large animals
1) Resuscitation (Hypovolemic/ Distributive/ Cardiogenic)
2) Maintenance (Supprotive care for disease or adverse effects of medication like Banamine)
3) Replacement (Water, electrolytes, proteins for GI disease, Liver, renal, neurologic
4) Nutrition: Adults, neonates, requirements, volume
What are parameters of the CV system that you can assess when looking at the hydration status of large animals
1) Heart Rate: Tachy or bradycardia
2) Mucus membranes: pink (shock or anemia), bright pink (increased capillary circulation), red (poor capillary perfusion), grey/blue: hypxia
3) CRT: <3seconds or prolonged
4) Blood pressure: pulse quality poor and jugular refill slow
5) PCV/TP: best for monitoring and evaluations of trends
not good for predicting hydration at initial exam since factors associated with disease can affect these
T/F: PCV/TP in large animals is helpful in determining hydration of the animal *
False
best for monitoring and evaluations of trends
not good for predicting hydration at initial exam since factors associated with disease can affect these
What do pale mucous membranes of a horse tell you
Shock; Anemia
What do red/brown mucous membranes tell you on a horse
poor perfusion; methemoglobinemia
What do bright pink mucous membranes on a horse tell you
increased perfusion; polycythemia
What do red/ purple mucous membranes in a horse tell you
poor perfusion; toxemia
eyeball recession in large animals
very good for assessing hydration stayus in calves
acceptable in ruminants and camelids
estimate mm recession and multiple by 1.6
not accurate in horses although eyeball recession is seen in hypovolemic foals
T/F: eyeball recession is an effective method of hydration assessment in horses
not accurate in horses although eyeball recession is seen in hypovolemic foals
How do you determine the hydration status of cows using eyeball recession
estimate mm recession and multiple by 1.6
Where are places you can do a skin tent in large animals
point of shoulder, neck, eyelid
variable by species, gender, and age
*Does not work well in animals with thick skin (male llamas)
What is seen of the neurologic status of animals that are dehydrated
lethargic obtinded, stuporous, comatose
(affects end-organ perfusion)
What is the temperature of patients that are severely dehydrated
cold extremities= poor peripheral perfusion
further coolness extends up the limb = more severe circulatory collapse
extremities warm up as shock is resolved
What is normal urine output
1-2ml/kg/hr
(out 50% of intake)
decreased by poor hydration, shock ,renal injury)
Large animals have renal azotemia if they have
elevated creatinine and an isosthenuric or hyposthenuric urine specific gravity
T/F: In horses and cattle, increases in urea nitrogen can be modest in renal azotemia due to excretion of urea into GI system
True
Why can you get pre-renal or renal azotemia with septic or hypovolemic shock in large animals
the decreased perfusion of the kidney that occurs with hypovolemic or septic shock can result in renal ischemia and consequent renal damage
Bacterial and toxic insults from septic shock can also damage the renal tissue
In large animals without renal disease, you would expect creatinine to ______ within 12-24 hours of fluid therapy
Half
In large animals, a core-peripheral temperature change of greater than 13F equals
less than 65% of CO
How do you do skin turgor in large animals to estimate the percent dehydration
pinch skin and twist 90 degree, hold for 1 second and release
measure the time it takes to return to normal
% dehydration = (2x seconds it takes) -4
What is the equation to estimate % dehydration in large animals using a skin tent
pinch skin and twist 90 degree, hold for 1 second and release
measure the time it takes to return to normal
% dehydration = (2x seconds it takes) -4
What is the equation to estimate dehydration in cows using eye recession
Estimated Dehydration (% of BW= degree of eye recession into orbit (mm) x 1.6
Dehydration in calves i estimated to be _________ when their eye recession into the orbit is greater than 4%
greater than 8% dehydrated
What the result of fluid therapy to reduce lactate levels in horses
Hyperlactatemia is not solely due to dehydration but also the disease processes going on.
Lactate will decrease but doesnt go down all the way due to other processes going on (ie sepsis)
The rate of lactate clearance is associated with prognosis
What are the levels of dehydration in calves (moderate, marked, and severe)
Moderate (5-8%) Eyeball recession of 2-4mm and skin tent of 4-6 seconds
Marked(8-10%) Eyeball recession of 4-6mm and skin tent of 6-7 seconds
Severe (10-15%) Eyeball recession of 6-8mm
and skin tent of 7-10 seconds
What is anion gap and how do you calculate it
[Na+] [K+] - [Cl-] -[HCO3-]
If the plasma concentration of bicarbonate decreases to buffer the effect of the increased chloride concentration, the patient is in _______________
Hyperchloremic acidosis
If the plasma concentration of bicarbonate decreases to buffer the effect of the increase in unidentified anions (lactate), the pation is in
Lactic acidosis
If the plasma concentration of bicarbonate increases to buffer the effect of the decrease in chloride concentration, then the patient is in
hypochloremic alkalosis
if the plasma concentration of bicarbonate decreases to buffer the effect of the decrease in weak concentration, then the patient is in
hypoproteinemic acidosis
is there increased protein (TP or albumin) with metabolic acidosis or alkalosis
metabolic acidosis
is there a decrease protein (TP or albumin) with metabolic acidosis or alkalosis
metabolic alkalosis
Why is dextrose mostly used in adult horses
to reduce the levels of triglycerides (negative energy balance)
When might you give sodium bicarbonate
in ruminants suffering from neonatal diarrhea or GI disease.
it is alkalinizing to resolve the metabolic acidosis (adding in Na+)
Rarely used in horses
when might you give magnesium to a horse
when they do not do well with calcium supplementation
why is treatment of metabolic acidosis using sodium bicarbonate so common in cows
because it is likely due to hyponatremia in calves and accumulation of strong anions (lactate) in cases of GI disease (enteritis, rumen acidosis, metabolic disorders, sepsis)
What is the base excess
calculated parameter that helps determine the variation of patient bicarbonate from the expected normal bicarbonate
Positive number with metabolic alkalosis and negative number with metabolic acidosis.
(BE= Patient HCO3 - 24)
Base excess is _____ with metabolic acidosis and ______ with metabolic alkalosis
Positive number with metabolic alkalosis and negative number with metabolic acidosis.
(BE= Patient HCO3 - 24)
How do you determine how much sodium bicarb you need to give to return the base excess to normal?
HCO3- requirement: BW (kg) x BE x (0.4 to 0.6)
0.4-0.6 is the fluid compartment for HCO3-
We use 0.5
When do you give dextrose to horses
1) Hypoglycemia
2) Anorexia
3) Negative energy balance- hypertriglyceridemia
*Add to crystalloid fluids at 1-5%
When adding Dextrose to fluids for supplementation, what percent makes it isotonic vs hypertonic
5% - isotonic
>10% Hypertonic
Why might you give 5% dextrose in water
istonic and delivers free water (No sodium) when dextrose is metabolize
foals do not metabolize sodium well
T/F: foals do not metabolize sodium well
True. give D5W
istonic and delivers free water (No sodium) when dextrose is metabolize
What should you be careful when supplementing potassium
Supplement orally if possible 0.2-0.4g KCl/kg/day
Mut IV max is
hourly: 0.5mEq K+/kg/hr
daily: 3-5mEq K/kg/24 hours (preferred because at an hourly rate the daily limit will be reached in 6-10 hours)
It can have effects on heart if you exceed this
When is calcium supplemented
to treat periparturient hypocalcemia in cattle, sheep, and goats
Too rapid admin can result in cardiac arrest so recommended to admin over a period of at least 15 minutes
hypocalcemia is also observed with several medical conditions including septicemia, enteritis, and hepatic lipidosis
Why might you need to supplement calcium in horse with Gi disease
they are hypocalcemia and they will benefit from calcium supplementation to help impove GI motility and improve muscle strength
How do you treat periparturient hypocalcemia in ruminants
Administer 1ml/kg Calcium Gluconate IV over at least 15 minutes
How do you deliver calcium for large animals for supportive care
Add up to 25ml Ca gluconate per liter of crystalloid fluids that are given at a maintenance fluid rate
Decrease this amount if admin fluids at a higher than maintenance rate
Why might you give magnesium (MgSO4) to arge animal
1) Horses with ileus
2) Cardiac arrythmias
3) Refractor hypokalemia and hypocalcemia
What are the different fluid administration route in large animals
Oral: functional GI tract, cheap, less invasive, nutrition, rehydration for midly affected animals
IV: Requires IV access, vein complications, shock tx, dysfunctional tract
SQ: IV cather not possible, moderately rapid absorption (1-2 hours), limtied volume due to volume to surface area
IO: neonates
Why do they use distilled water mixed with crystal salt (ECF) for IV fluid therapy in livestock
Cost- commercial IV fluids are very expensive for that size
What are the different drip sets used in large animals
10 drop/ml: 1 drop/sec= 360ml/hr
15 drop/ml: 1 drop/sec= 240
What IV catheter size should you choose for hypovolemia shock treatment in horses
10G, 12G, 14G most commonly
diameter affects rate of the fluid
How do you do fluid resuscitation on horses
Isotonic crystalloid
10-20ml/kg
20-30minutes
Re-assessment of clinical and lab parameters
Usually 2-3 boluses
ex 20x500kg= 10,000 or 10 L bolus
reasess and repeat as needed
What is the goal of fluid resuscitation in large animals
rapid correction of deficit
minimizing effects of fluid overload
incremental approach and frequent reassessment
goal: restore tissue perfusion
What is maintenance rate for adult livestock
3ml/kg/hour
range 2-4 ml/kg/hr
ex: 500kg= 36L/day
What is the maintenance rate of equine
2-3 ml/kg/hr
60ml/kg/day
less when not eating (1ml/kg/hr)
ex: 500kg = 30L/day
How do treat for ongoing losses in livestock
can be due to enteritis, colitis, sweating
expectation is 5-10% BW
so add another 2-4 ml/kg/hr
*twice maintenance
T/F: maintenance fluid rate and requirements are the same for neonates and adults
False- they have different physiology
Oral fluid therapy is commonly used in livestock. But why is it not used in horses, contraindicated?
Gi diseases and shock: abdominal distension, diarrhea, reflux, colic (with the exceptions of large colon impaction and some large colon displacements)
*Will increase abdominal distension and discomfort
Fluid absorption is also diminished.
When should oral fluids not be used in horses
Gi diseases and shock: abdominal distension, diarrhea, reflux, colic (with the exceptions of large colon impaction and some large colon displacements)
Foals do not drink water until
they are 1 month or older
How is oral fluid therapy performed in livestock
Ruminants: Oral gastric tube
Calves: bottle, bucket, oro or nasogastric tube
horses: nasogastric tube
foals: pan/ bucket/ nasogastric tube
When should you do oral fluid therapy in horses
when they have functional GI tract and no shock
Oral fluid therapy stimulates the
gastrocolic reflex- encourages movement
What should you always do when performing oral fluid therapy
always check for reflux first
What is added to fluids in oral rehydration therapy in livestock
1) Electrolytes
2) Glucose or glycine
3) Alkalizing activity (acetate, propionate, citrate, bicarbonate)
What is significant about colostrum in dairy breeds
there is high milk production that dilutes colostral IgG
need to administer >10% BW within 6 hours of birth (while >5% BW within 6 hours for nondairy breeds)
How much colostrum should you deliver to neonates
dairy breeds: need to administer >10% BW within 6 hours of birth (while >5% BW within 6 hours for nondairy breeds)
ex: 50kg foal is 2.5L, administer max 500ml at one time (or per hour)
How much milk (replacer) to calves and foals drink per day *
Calves drink 15-20% BW/day
Foals drink 20-25% BW/day
Feeding larger volumes of milk (replacer) increases the risk of
Clostridial Enterocolitis
*start at lower volume per feeding and gradually increase
What might increase the milk (replacer) you feed to neonates by 50%
cold weather
What is the blood volume of a horse
about 8% of BW= 40L
How do you perform rapid volume expansion in a horse
Hypertonic Saline (7.2% NaCL) and then should always be followed by volume administration using BES (Balanced Electrolyte Administration)
What vein is best for rapid fluid resuscitation in horses
Jugular vein - large bore catheter: 10 or 12G
two catheters
large bore admin set to connect fluid bag to cathether
why is oral fluid resuscitation not ideal for hypovolemic horses
if hypovolemic, blood flow to the GI tract is reduced
What is proper IV catheter care in the horse
clean gloves
flush q6hrs
limit aspiration
end cap: remove or wip with alcohol before use, change it daily, and do not lay down
inspect: at least q6hr, leakage at insertion, pain, heat, swelling
check wrapping
What are the indications for using dextrose in horses *
1) Hypertrigylceridemia
2) Prolonged anorexia
3) Breeds are risk: miniature horses, ponies, donkeys, overweight animals
4) Laminitis- hyperinsulinemia
What are reasons to stop fluid therapy in a horse
1) Clinical and laboratory assessments
2) Eating and drinking (not 100%)
When do you give plasma in adult horses
colitis, DIC concerns, and to replenish clotting factors
When should you give blood transfusions to adult horses
1) Acute or Chronic
2) PCV <20% (nx is 33%)
3) Elevated lactate
4) Blood loss estimated >30% of blood volume
5) HR (>80bpm), mucus membrane color, sweating, colic, cold extremities, hypotension
What is usually the first lime therapy in adult horses to combat hypovolemia
BES
What should you do for oral fluid therapy in a horse
*only for large colon impaction or large colon displacement
-Use a nasogastric tube
5-8L q 2-6 hours
with electrolytes (BES)
NaCl (28g), NaHCO3 (17g), KCl (3g), 5L water
What is caloric requirements for 500kg adult horse for maintenance
16.4Mcal/day (33kcal/kg/day)
What should you for maintenance support in a horse with inability to eat
small bore nasogastric feeding tube
-complete pelleted feed
or parenteral nutrition (IV) of dextrose, protein, lipids
What is the blood volume of a foal
16% of BW (different from the 8% of adult)
so for a 50kg foal, it is about 8L
What is the normal urine of USG of foals
1.001-1.010
Milk is low in _______ so foals are not very tolerant to supplementing ________
sodium
How do you do fluid resuscitation on a hypovolemic foal?
10-20ml/kg
Most are recumbent and hypovolemic foals need 2-3 fluid boluses
ex: 50kg foal: 1 L bolus administered 2-3 times
**Monitor perfusion parameters and urine production
How do you treat failure of transfer of passive immunity in a goal
Plasma IV
1-2L/50 kg foal
or
Colostrum via NG tube (1.5-2L/ 50kg foal; 500ml) good quality
How do you treat Clostridial entercolitis in foals
IV- maintenance, replacement, nutrition
or disease with functional GI tract: Colostrum or milk via nasogastric feeding tube
How do you treat neonatal isoerytholysis in foals
resuscutation can include oxyglobin or blood transfusion
What are the problems you get when doing oral fluid/milk therapy in foals that are sick (dysfunctional GI tract)
GI related diseases: ileus, colic, gas accumulation, diarrhea
rare to do oral- do IV fluid instead
How do you manage IV fluid therapy more conservatively in foals
Rate: 2-4ml/kg/hr
but there is a fluid restrictive rate (not at altitude) of
100ml/kg/day for first 10kg BW
50ml/kg/day for 2nd 10kg BW
25ml/kg for remaining kg BW
*Monitor foals closely for adequacy of fluids or fluid overload
What are the same across mammals in regards to fluid therapy
1) Maintenance: 2-3ml/kg/hr
2) A quarter shock dose = 20ml/kg IV as bolus
3) When in doubt, balanced crystalloids
What is the difference between maintenance fluid doses in adult and neonate livestock
Adults: 2-3mL/kg/hr
Neonate: 3-4mL/kg/hour
What is the Holliday Segar Rule
It is a rule to account for maintenance fluid requirements in neonates livestock
For first 10kg: 4mL/kg/h (100mL/kg/day)
For second 10kg: 2mL/kg/h (50mL/kg/day)
For every kg thereafter 20mL/kg/day (1ml/kg/h)
When should you give maintenance fluids to livestock
1) Patient is not drinking for extended time
2) Behicle for fixing electrolyte/ acid base/ energy disturbance without overproviding fluid volume
3) Increased maintenance requirements in the face of increased metabolic rate (ex: sick, weather, etc)
Most patients will have decreased ____________ while being administered isotonic fluids if you are keeping up with requirements (blood pressure and osmolarity)
decreased thirst drive
When should you consider doing fluid therapy in neonate livestock
as soon as there is slight separation in eyeball recession 6-8% dehydrated and neck skin tent of 5-10 seconds
What is the most accurate representation of the patient’s current hydration status if the kidneys are working in livestock
Urine specific gravity
What is the labwork evidence of dehydration in livestock
USG: >1.025 in adults and >1.014 in neonates
*the best (when kidneys are working)
Elevated PCV/TS
Elevated Serum Lactate: Dehydration, Sepsis, and Liver disease
Pre-renal azotemia: elevations in creatinine which decrease 50% over 12-24hours of fluid therapy. >1.8mg/dL in all species except camelids (Creatinine <2.7mg/dL) *
What is the replacement rate for livestocks
based on the est % dehydration
(BW kg x % dehydration = L to replace)
as bolus or CRI
20ml/kg (1/4 shock dose) is also reasonable
What are the ongoing losses that you should account for in livestock
1) VOmiting (pigs)
2) Diarrhea
3) Sepsis
4) Excess urine production
5) Lactation (140L/day)
6) Osmotic GI “loss”
T/F: you can do oral for volume repletion in pigs
False_ no pigs, they need to be heavily sedated
When should you not use oral hydration for volume depletion in livestock
1) Never pigs
2) No ileus or vomiting
3) No bloated animals
Where can you give IV fluids in pigs
ear catheter, other livestock is jugular
T/F: livestock are at lower risk of thrombophlebitis compared to other species (horse, dog, cat, etc)
true
T/F: it is really difficult to give SQ fluids in livestock
true- their skins are really tight
what species are especially tolerant of clean but non-sterile IV fluids
ruminants like cows and goats
this is a reasonable costsaving measure, particularly in production animals
What livestock species do you worry about with fluid overload
Camelids and neonates
also other animas if they have cardiac disease and pulmonary disease
also dont want to damage the glycocalyx
What is a normal pH of livestock
7.35-7.45
the amount of bicarbonate needed to bring your pH back to a normal range
Base deficit (BE)
calculate the bicarb needs:
Weight (kg) x 0.6 x base deficit = mmol of HCO3-
In livestock, how do you correct the base deficit
with bicarbonate
-correct half the base deficit as a slow bolus and the remainder over 12-24 hours
-8.4% Sodium bicarbonate contains 1meq/mL
-Baking soda contains 12mmol/g of HCO3
-Isotonic bicarb: 150mEq of NaHCO3/L (12 g of baking soda; 150ml of HCO3)
Calves with scours that present in lateral recumbency likely have a base deficit of at least
10
What is the physiochemical “Stewart” approach
that acid base balance is determined by the balance of OH- / H+ ions in solution rather than just pH alone
‘H+ concentration is determined by 3 independent variables
1) Strong Ion difference
2) Partial pressures of CO2
3) Total Weak Acids (Atot)
‘H+ concentration is determined by what 3 independent variables
1) Strong Ion difference
2) Partial pressures of CO2
3) Total Weak Acids (Atot)
What is the strong ion difference
strong ions are those which fully dissociate in water and the difference between these anions and cations is the strong ion difference
[Na+] + [K+] - [Cl-]= SID3
must maintain electroneutrality
H20 + CO2 <-> H2CO3 <-> H+ + HCO3
What is normal TCO2 in livestock
20-30mmol/L
Plasmalyte has:
Na: 140
Cl: 98
K: 5
What is the SID of this fluid
[Na] + [K]- [Cl]
= 47mmol/L
this is high so plasmalyte is a slightly alkalinizing solution
If you have a normal strong ion difference, what might be causing your acid-base disturbance?
Some sort of anion gap due to
1) unmeasured anions like albumin and phosphate
2) Total weak acids (A-) like uremic acids, organic acids, salicylate (Aspirin/ Peptobismol)
3) Lactate
What might substances might be causing an anion gap in livestock
K- ketones
L- lactate
U- uremic acids
E- ethylene glycol
How do you correct hypocalcemia in livestock
IV- as bolus via simplex or in crystalloids, 1 bottle CMPK or CalGluc/cow (can be scaled down for small ruminants
Oral: calcium gluconate oral paste
*Sq may be irritating
What is the max rate of potassium in livestock before cardiac monitoring is required
0.5mEq/kg/hr
if higher they can get standstill
If you give a 205mEq bottle to a 680 kgcow over 30 minutes, why might you be worries
this is at a rate of 0.6mEq/kg/hr which is over the 0.5mEq/kg/hr in which you need to begin to monitor their heart for standstill
You have a goat with urolithiasis. What should you do?
1) Post-Renal Azotemia will resolve readily after the obstruction is removed.
2) Fluids to drive potassium down
a) dextrose at 1-2x maintenance requirement
b) Isotonic with low potassium concentration (0.9% NaCl)
3) Calcium gluconate (25-50ml/L)
4) Insulin
*Should drive potassium down
What should you do before panicking about hyperkalemia in livestock?
Make sure the sample was not hemolyzed
When should you worry about providing energy in livestock
1) Animals off feed for >2 days
2) Negative energy balance (lactation or pregnancy)
3) Neonates off feed >4-6 hours
4) Causes of hypoglucemia (sepsis, hyperinsulinemia, and liver disease)
What might falsely elevate serum potassium in livestock
Hemolysis
Why should you not tube neonatal ruminants more than a couple times
Omasal groove will go away if they do not nurse
if you drop milk into the rumen and they will end up with ruminal acidosis
How might you correct livestock with hyperglycemia
these are often camelids that have blunted insulin response in face of disease or animals with sepsis
Give insulin as SC bolus or CRI
Camelids often develop a blunted __________ response in the face of disease
blunted insulin response in the face of disease
Does hyper or hypoglycemia develop because of sepsis
hyperglycemia
Potter, a 3-year old, 20 kg FS (female spayed) Pointer mix, presents to your clinic for an acute onset of vomiting (~ 12 hours, vomited large amounts of liquid 10+ times). The owner also reports that she may have ingested some of her bedding material 3 days ago. On initial physical exam, she is very dull with a temperature of 99.2 degrees F, pulse rate=160 beats/minute, respiratory rate 10 and pale pink mucous membranes with ~ 3 second capillary refill time. She is unable to stand on her own without assistance.
Based on primary survey information, is Potter in shock?
yes
Which of the following fluids will create the highest short-term intravascular volume expansion?
Hypertonic (7.5%) saline
A 2 year old FS Beagle (12 kg) presents with severe, acute vomiting and bloody diarrhea of 36 hours duration. She is obtunded, has a heart rate of 180 bpm, and has pale mucous membranes with a capillary refill time of 3 seconds. You place an intravenous catheter and run some initial bloodwork. Her PCV is 65% and her TP is 7.2 mg/dL. (3 points)
Pair the following “shock volume” with the appropriate fluid type for THIS patient
Hypertonic crystalloid
Isotonic Crystalloid
Synthetic Colloid
Hypertonic crystalloid: 60mL
Isotonic Crystalloid: 1000mL
Synthetic Colloid: 240mL
Sadie is a 2 year-old female spayed Labrador presented for vomiting and diarrhea of 5 days duration. She weighs 25 kg. Her skin turgor is slightly decreased; she has pink but tacky mucous membranes with a CRT of 1.5 seconds. The position of her eye in the orbit is normal; her heart rate is 100 bpm with strong pulses. You estimate her to be have moderate dehydration (let’s pick 7% for our calculations).
The physical examination findings described above are characteristic of what type of fluid losses:
Extracellular fluid compartment (isotonic loss
Which of the following is an indication for mechanical ventilation?
A) Hypoxemia without oxygen supplementation
B) Severe hypoxemia without oxygen supplementation
C) Severe hypoxemia on oxygen supplementation
D) Hyperventilation on oxygen supplementation
C) Severe hypoxemia on oxygen supplementation
You are treating a llama that is sick and appears 5% dehydrated on presentation and has a presenting creatinine of 6.3 mg/dl. You initially replenish the calculated fluid deficit over the first 4 hours of fluid therapy and then maintain the llama on a balanced electrolyte fluid at a fluid rate of 6 ml/kg/hr. The following day, about 24 hours from the initiation of fluid therapy, you check a serum creatinine level again and it is 3.0 mg/dl. Normal creatinine for a llama is 1.2 to 2.6 mg/dl. Since the creatinine did not return to normal after 24 hours of fluid therapy, you determine that the llama must have renal failure.
False- The fluid therapy successfully decreased the creatinine in half within 24 hours. That is consistent with a normal response for pre-renal azotemia.
You are treating a 40 kg septic calf that does not appear dehydrated, has hyperemic mucous membranes and extremities are still warm. Laboratory test results are below with normal values in parenthesis (normal):
Creatinine 3.8 mg/dl (0.6 – 1.0)
Glucose = 34 mg/dl (80-100)
Na = 133 mEq/L (132-144)
K = 3.3 mEq/L (3.8-5.6)
Cl = 101.8 (90-102)
Bicarbonate = 12.4 mEq/L (23-33)
Base Excess = -12 mEq/L
SID = 34.5 mEq/L (40-45)
Anion Gap = 22.1 (15-23)
Based on these findings, which of the selections below would be the best choice of initial fluid therapy to help resolve the major metabolic problems in this calf and replace 1/2 of the total body base deficit?
1 liter of plasmalyte with 2.5% dextrose and 120 mEq of sodium bicarbonate administered at a rate of 6 ml/kg/hr.
In this calf you want to address 3 primary things;
1) The azotemia noted by the elevated creatinine.
2) The hypoglycemia
3) The metabolic acidosis due to both low sodium and slightly high anion gap (probably lactate)
To do this, you would like a fluid rate above maintenance coupled with an appropriate glucose supplementation and 1/2 the Total Body Deficit of bicarbonate. Since you will have a higher than maintenance fluid rate, dropping the dextrose in the solution to 2.5% instead of 5% is justified. However, it is good to check after the first hour to make sure that is satisfying the needs of the calf.
You examine a 9-year-old horse for signs of colic. The horse has been colicky for 3 days and during that time frame has been administered Banamine (flunixin meglumine) 500 mg PO q 12 hrs. After your examination you are suspicious of a large colon impaction. The horse’s examination findings are listed below:
Weight: 500 kg
HR: 62 bpm
RR: 18 bpm
T: 100.5F
MM: tacky, pink, CRT: 3 sec.
Extremities: cool, but not cold
PCV: 45%
TP: 7 g/dl
Lactate: 3 mmol/L
Creatinine: 3.5 mg/dl
What type of fluid therapy and rate is the most appropriate to use in this horse:
A combination of IV and enteral fluids: IV fluids at 3 L / hr and enteral fluids at 5 L every 4 hrs with electrolytes added
If the horse was not azotemic only providing enteral fluid therapy would likely be sufficient and effective. However, this level of azotemia paired with the known use of NSAIDs in a horse that was not eating well and therefore likely was not drinking enough is concerning for renal azotemia in addition to likely a pre-renal component. This is significant enough to warrant diuresis and attempt to prevent further renal injury. Therefore we would suggest the use of IV fluid therapy at twice maintenance. Additionally enteral therapy using BES (water with electrolytes added) is beneficial to hydrate the ingesta and stimulate GI motility.
You are working with an owner that just lost a mare that was nursing a foal due to colic in the mare. The owners have purchased some Mare’s Match milk replacer for the foal. The foal is 3 weeks old and weighs 100 lb. The Mare’s Match label says to feed 25% of the foal’s body weight per day as liquid milk replacer. After discussing feeding plans with the owner, they decide that they can only feed 3 times daily. Based on this information, how many LITERS of Mare’s Match milk replacer should they currently feed to the foal per feeding based on calculations using the Mare’s Match label instructions
3.8
Total amount of milk replacer per day is calculated as
(100/2.2) X 0.25 = 11.36 L per day. Divided into 3 feedings, that would be 3.78 L or about 3.75 L per day.
You examine a 440 lb steer with diarrhea. In your physical exam, you find that the eyeballs are recessed about 4 mm and the steer has a skin tent along the neck of about 6 seconds. Based on this information, you estimate that the steers hydration deficit in liters is:
Based on eyeball recession and skin tent, you estimate that the animal is 8% dehydrated. The steer weighs 200 kg (440 lb). Thus, the hydration deficit is
200 kg X 0.08 = 16 kg = 16 L
You are ausculting a horse with a respiratory rate of 24 breaths per minute. Normal intensity bronchial breath sounds are heard at the larynx and trachea. The breath sounds over the thorax consist of bronchovesicular sounds in the cranial ventral thorax that are softer than the tracheal sounds. Vesicular breath sounds can be heard in the cranial dorsal lung fields and become softer to inapparent in the caudal dorsal lung fields. What would be the best clinical interpretation of the most likely respiratory pathology?
Normal
This is a standard description of normal breath sounds in most animals. Bronchial sounds are normally heard over the upper airways and in most animals. They are generally louder than the loudest thoracic breath sounds. Bronchovesicular breath sounds are typically heard in the cranial ventral thorax and then become more vesicular or absent as you move away from the large airways.
T/F: PCV and TP is a good method at assessing hydration
it is not!
lactate is a good measure because it reflects tissue perfusion
