Mod 1 - Fluid Therapy (8/14) Flashcards
Quiz 1
Water makes up 1% of an animal’s body weight. 2% is intracellular fluid and 3% is extracellular. Extracellular fluid is made up of 4, 5, 6, & 7.
- 50-60%
- 40%
- 20-30%
- plasma (5%)
- interstitium (15%)
- lymph (2%)
- transcellular (1-3%)
What 5 signalments can alter total body water?
- age (young = more, old = less)
- sex (M > F)
- species
- level of exercise
- body condition
ICF contains a higher concentration of 1.
ECF contains a higher concentration of 2 & 3.
- K+
- Na+, Cl-
How much fluid does a patient intake per day?
40-60 mL/kg/day
How much fluid from a patient is lost per day?
24-48 mL/kg/day
What 2 things can cause an abnormal fluid balance?
- decreased fluid intake - fasting, anorexia, NPO
- increased fluid losses - V+, D+
What 5 things can cause an isotonic fluid loss?
- V+
- D+
- hemorrhage
- 3rd space
- sweat
What 2 things can cause a hypertonic fluid loss?
- Loop diuretics (K+)
- Addison’s disease
What 3 things can cause a hypotonic fluid loss?
- renal failure
- respiratory loss
- burns
What are the 4 steps to developing a fluid therapy plan?
- assess patient’s need for fluids
- determine dose
- select type and route
- select rate of administration
What are 3 reasons to administer fluids to a patient?
- maintain euhydration
- restore circulating volume (dehydration, hypovolemia)
- treat a specific disease process
What is hypovolemia?
Emergency Y/N?
a decrease in effective circulating volume, resulting in circulatory shock
EMERGENCY
What are the 2 causes of hypovolemia, with examples of each?
- absolute - fluid loss, hemorrhage
- relative or distributive - vasodilation (sepsis, SIRS, iatrogenic)
What is dehydration?
Usually a chronic loss of total body water
Dehydration vs. hypovolemia
1. which should be replaced rapidly (minutes to hours)?
2. which should be replaced slowly (days)?
- hypovolemia
- dehydration
How do you calculate a fluid dose?
deficit/dehydration + maintenance + losses
What is the maintenance rate for a patient?
40-60 mL/kg/day (this will vary from patient to patient!)
Regarding dehydration, what compartment is the total body water typically pulled from?
What about in large animals?
extracellular fluid (vasculature)
ECF & colon or rumen
What happens when we “guess-timate” loss of fluids due to dehydration?
we often overestimate the losses - important to reassess frequently!
How do we get the amount of fluids we need to replace a deficit/dehydration?
% dehydration x weight (kg) = fluid amount (L)
List 4 objective ways to measure dehydration.
- HR
- CRT
- PCV/TS
- creatinine
List 5 subjective ways to measure dehydration.
- skin elasticity
- sunken eyes
- MM moisture
- MM color
- mentation
T/F - we can tell if a patient is 5% or less dehydrated on physical exam.
False - we can’t!
T/F - a patient over 15% dehydrated will be dead.
True
T/F - fluid therapy should be tailored to the patient.
True
What 2 things can affect PCV?
- anemia (dec. RBCs)
- splenic contraction (inc. RBCs)
What 3 things can affect TS?
- inflammation (inc. fibrinogen in LA)
- renal disease (dec. protein)
- gastrointestinal disease (dec. protein)
What are 4 sensible losses that are included in the estimation of fluid losses?
- V+
- nasogastric reflux
- D+
- hemorrhage
Calculate the fluid dose:
500 kg horse estimated at 6% dehydration with 4 L of reflux every 6 hours (Q4).
M: 500 kg x 50 mL/kg/day = 25,000 mL/day = 25 L
D: 500 kg x 0.06 = 30 L
L: 4 L x 6 hr = 24 L/day
25 L + 30 L + 24 L = 79 L/day = ~3 L/hr
T/F - it’s best to calculate a fluid plan for 24-48 hours and reassess after.
False - every 12 hours or sooner
What are 7 considerations we need to think about when deciding the route of fluid administration?
- species
- patient compliance
- owner finances
- disease treated
- volumes required
- facilities available
- monitoring
Water available for oral consumption is a good choice for patients that…? (2)
- only need maintenance
- are able to consume it on their own
Enteric or intragastic fluid intake
1. name 3 pros
2. name 4 cons
PROS:
1. low cost
2. fewer side effects
3. for maintenance & replacement
CONS:
1. volume limitations
2. can’t give if refluxing
3. not for >8% dehydration
4. possible trauma/pneumonia
IV fluid intake
1. name 3 pros
2. name 4 cons
PROS:
1. allows for resuscitation & faster administration
2. fluids go directly into vasculature
3. good if PO/IG is not an option
CONS:
1. non-physiological route (may cause dehydration when stopped, can quickly affect electrolyte balance)
2. caution with certain diseases
3. catheter complications
4. more costly
What 4 diseases should you take caution with when administering IV fluids?
- heart failure
- anuria
- urinary obstruction
- pulmonary edema
Intraosseous fluid intake
1. when would this route be beneficial?
2. what species is this route great for?
3. what 4 locations can this be done?
4. what is 1 risk?
- difficult to get venous access
- pigs
- 1) tibia, 2) radius, 3) femur, 4) humerus
- osteomyelitis
SQ fluid intake
1. name 1 pro
2. name 3 cons
PRO:
1. many administration sites
CONS:
1. limited volume given
2. slow absorption
3. must be isotonic
Rectal fluid intake
1. name 3 pros
2. name 4 cons
PROS:
1. low cost
2. good to use if no venous access
3. absorption similar to PO
CONS:
1. inaccurate due to losses
2. less accepted by owner/patient
3. rectal injury
4. can’t use with severe D+
Intraperitoneal fluid intake
1. which is the fastest: SQ, IP, or IV?
2. which is the slowest?
3. name 2 risks
1 & 2. SQ < IP < IV
3. 1) peritonitis, 2) organ puncture
What are crystalloid fluids?
What are colloid fluids?
salt solutions
fluids with large molecules that stay within the vasculature to inc. oncotic pressure
T/F - colloids are used for small volume resuscitation and maintenance fluids.
False - small volume resus. only!
Crystalloids
When are:
1. isotonic fluids appropriate?
2. hypotonic fluids appropriate?
3. hypertonic fluids appropriate?
- replacement fluids for hypovolemia & dehydration
- maintenance fluids for normal losses
- resuscitation
Isotonic crystalloids have high 1 (electrolyte).
Hypotonic crystalloids have lower 2 and higher 3, 4, and 5.
- Na+
- Na+
- K+
- Ca++
- Mg++
How much crystalloid fluids remains in the vasculature 1 hour post-infusion?
25%
(75% gets redistributed to the interstitium)
Large volumes of Na+ cause 1 diuresis.
- K+
What is the IV dose of K+?
What rate of K+ should be given, and if it’s any higher than that, toxicity may occur?
20-40 mEq/L
<5 mEq/kg/hr
What 2 things can occur with hypocalcemia?
- anorexia
- dystocia/lactation
What is the small animal dose of Ca++?
50-150 mg/kg
Mg++ is often depleted in (acute/chronic) illness. It is important in 1 function. With Mg++ toxicity, you will often see 2, 3, and, if given orally, 4.
chronic
1. neuromuscular
2. depression
3. neurological signs
4. diarrhea
What is the dose for Mg++?
4-16 mg/kg/day
Hypoglycemia is common in 1 & 2.
- neonates
- toy breeds
Why should you avoid Dextrose 5% in water?
The dextrose is rapidly metabolized and then you’re just giving water, which will cause further electrolyte imbalances & diuresis.
What is the problem with replacement fluids?
They contain a lot of Na+, which can cause diuresis and rebound dehydration, depletes electrolytes, and any excess Na+ retained can cause edema.
Saline is 1% 2 and causes 3 and 4 metabolic acidosis. This metabolic acidosis results in renal vaso_5_ and (increased/reduced) renal perfusion.
- 0.9%
- NaCl
- hypernatremia
- hyperchloremic
- vasoconstriction
reduced
When is 0.9% NaCl indicated? (2)
- hyperkalemia
- hypochloremia (or metabolic alkalosis)
With 0.9% NaCl, what causes K+ to shift out of cells to be excreted?
Hyperchloremia, or metabolic acidosis
What are the 2 things that can cause hypovolemic shock, with examples of each?
- dec. effective circulating volume - severe dehydration, hemorrhage, burns
- circulatory collapse - loss of vascular tone, inc. endothelial permeability (sepsis, anaphylaxis)
How do you treat hypovolemic shock?
rapid fluid resuscitation
What is the primary goal of treatment of hypovolemic shock?
preservation of organ function
What is the shock dose of isotonic crystalloids?
Why should we give 25% of the shock dose?
60-80 mL/kg
Because the risk of overestimating how much fluids to give could be fatal!
When should you reassess and repeat a shock dose of fluids?
when the animal has not improved
How do you know when you can start maintenance fluids (& no longer give shock boluses)?
when the patient’s vitals stabilize
How many times can you give a shock bolus consecutively?
up to 3x
Hagen-Poiselle’s Law deals with 1 & 2 to maximize the fluid rate.
What should 1 & 2 be to give the max amount of fluids as fast as possible?
- diameter
- length
diameter = as large as possible
length = as short as possible
What are 6 things that can increase fluid rates?
- inc. catheter or extension diameter
- dec. catheter or extension length
- use 2 catheters
- remove any extension sets
- use pumps
- use a slam bag or utilize gravity
Hypertonic crystalloids are used for (small/large) volume resuscitation.
What happens when you use hypertonic crystalloids?
small
rapid fluid shift to intravascular space - interstitium first, then intracellular space
How big is the expansion of the intravascular space when using hypertonic crystalloids?
~4x the amount given
How long does the volume expansion last when using hypertonic crystalloids?
45min
What are 4 effects of giving hypertonic crystalloids?
- improves CO, stroke volume, MAP, & cardiac contractility (+ inotrope)
- dec. ICP
- anti-inflammatory
- anti-edema
What are 2 contraindications for using hypertonic crystalloids?
- hypernatremia
- uncontrolled blood loss
T/F - natural colloids (blood, plasma, albumin) can be used for resuscitation.
False - worry about possible anaphylactic reactions
What are 2 indications to use colloids?
- dec. oncotic pressure
- rapid expansion of intravascular volume
What is a side effect in cats/dogs that can occur when using colloids?
coagulation problems - inhibition of factor VIII and von Willibrand factor
What are 5 safety considerations you should think about when considering fluid therapy?
- fluids are a DRUG
- electrolyte imbalances can occur (esp. with IV)
- be cautious with K supplementation
- overdose may result in pulmonary edema, volume overload, hemodilution
- may inc. mortality in septic & post-op patients
T/F - we don’t need to rush when giving fluids - they can be discontinued whenever the DVM is ready.
False - work to discontinue fluids ASAP
What are 4 ways to monitor fluid therapy?
- PE
- PCV/TS Q6-12hrs
- VBG (electrolytes, lactate, creatinine)
- USG
The patient should be stable for 1 hours before you should discontinue fluids. Weaning should be (gradual/immediate).
12-24hrs
gradual
