IV fluids Flashcards
What is the major component of all body fluids?
Water
When there is equilibration of water between compartments, what has been reached?
Homeostasis
What is the approximate total body water value for adult dogs & cats?
Neonates?
- 60%
- 80%
Do older patients have more or less total body water than adults?
Less
What is the 60:40:20 rule?
60% BW is water, 40% ICF, 20% ECF
Fluid needs are estimated based on what?
Lean body weight
How do you calculate lean body mass with a normal body weight?
With an obese body weight?
With a thin body weight?
- Normal body weight x 0.8
- Obese body weight x 0.7
- Thin body weight x 1.0
Is ICF composition similar to or different from ECF?
Very different from ECF
Is it easy or difficult to change ICF?
Difficult
ECF is composed of what?
Any fluid that is not inside a cell.
Changes in hydration are markedly affected where?
ECF
Where do we target when trying to change hydration status?
ECF
How much of ECF is intravascular?
What is this portion mostly composed of?
- 1/4
- Plasma
3/4 of ECF is composed of what?
Interstitial fluid
What does blood volume equal?
Plasma + erythrocytes
What is the blood volume of cattle?
60 mL/kg
What is the blood volume of dogs?
90 mL/kg
What is the blood volume of horses?
70 (TBs 100) mL/kg
What is the blood volume of cats?
65 mL/kg
What is the blood volume of sheep?
60 mL/kg
What is the blood volume of pigs?
50 mL/kg
What differs significantly between ECF and ICF?
Concentration of solutes
When total number of anions and cations in all body fluids is equal, what is maintained?
Electroneutrality
What are the 2 primary ECF cations?
Which is most abundant?
- Na+, K+
- Na+
Which ECF cation is present in small amounts but very physiologically important?
K+
What are the 2 primary ECF anions?
Cl-, HCO3-
What are the 2 primary ICF cations?
K+, Mg2+
What are the 2 primary ICF anions?
Organic phosphates, proteins
In diseased states, fluids are usually initially lost from where?
ECF
What are 3 types of fluid & solute loss?
- Loss of hypertonic fluids (solute in excess of water)
- Isotonic loss
- Loss of hypotonic fluids (water in excess of solute)
Which type of fluid/solute loss is the one most commonly seen under anesthesia?
Isotonic loss
Most of ECF is in what 2 areas?
- Interstitial compartment
- Intravascular space
Fluid division between plasma and interstitium maintains what?
Effective circulating volume
What are 4 examples of forms of water loss?
- Urinary
- Fecal
- Respiratory (panting)
- Cutaneous evaporation
What are 2 examples of cutaneous evaporation?
- Salivary (cats)
- Eccrine sweat glands (dog foot pads)
The function of renal solute load in diet and obligatory renal water losses for urinary solute excretion determine what?
Water requirements
What is the water requirement for small dogs?
Large dogs?
Cats?
- 60 mL/kg/d
- 40 mL/kg/d
- 50-80 mL/kg/d
Are maintenance fluids given in anesthesia?
No
How are maintenance fluid rates calculated in very large (> 50 kg) or very small (
- BWkg^0.75 x 70 = mL/day
- (BWkg x 30) + 70 = mL/day
What are 4 factors a patient history can uncover?
- Duration of issue
- Estimate losses
- Eating/drinking
- Panting, febrile
What is the most common fluid given in anesthesia?
Crystalloids
Solutions with electrolyte and non-electrolyte solutes able to enter all body fluid compartments are known as what?
Crystalloids
Where do crystalloids primarily exert their effects?
Interstitium & ICF spaces
In a balanced crystalloid, the composition resembles what?
ECF
What type of crystalloid composition does not resemble ECF?
Non-balanced
What are 3 examples of balanced crystalloids?
- Lactated Ringers (LRS)
- Normosol-R
- Plasma-Lyte 148
What is an example of a non-balanced crystalloid?
Saline
Every 1 mL of blood loss should be replaced with how much crystalloid?
3 mL
Where do colloids primarily exert their effects?
Intravascular compartment
What are 2 indications for the use of colloids?
- Shock
- Hypoproteinemia
What are 4 examples of colloids?
- Plasma
- Dextrans
- Hydroxyethyl starches
- Hemoglobin-based oxygen carrying fluid
What are 4 examples of parenteral route of administration for fluids?
- Subcutaneous
- Intraperitoneal
- Intraosseous
- IV
Subcutaneous fluid is only given in what type of patient?
Stable
What can prevent good uptake of fluids given SQ?
Vasoconstriction
What type of fluid is given SQ?
Isotonic
What are 4 things to be cautious about when giving fluids SQ?
- Thermal burns
- Infection
- Cellulitis
- Skin necrosis
Are there any advantages to giving fluids intraperitoneally?
No, can be potentially hazardous.
Capillary beds of medullary vascular system allow access to the vascular space for what route of administration?
Intraosseous
What is an alternative route of administration to IV in neonates?
Intraosseous
What is a form of administration that is used short-term in emergency situation?
Intraosseous
What is the preferred route of administration when blood volume expansion is needed?
IV
Which route of administration is better in a critically ill patient, IV or SQ?
IV
What are 6 potential complications of IV fluid therapy?
- Extravasation
- Thrombosis/thrombophlebitis
- Volume overload
- Infection
- Embolism
- Exsanguination
What are 2 examples of drugs that can cause extravasation?
- Thiopental
- NSAIDs
What are 7 basic things that are monitored during fluid therapy?
- HR
- RR
- CRT
- MM color
- Temperature
- Mentation
- Urine production
What are 4 other measurements taken during fluid therapy?
- Central Venous Pressure (CVP)
- Systemic Arterial Blood Pressure (ABP)
- Pulmonary Capillary Wedge Pressure (PCWP)
- Cardiac output (CO)
Anesthesia and surgery disrupt what?
Homeostasis
What is the goal of peri-anesthetic fluid management?
Correct abnormalities as much as possible before anesthetic event.
Most anesthetic drugs negatively effect what?
Cardiovascular and renal function
What are 4 reasons to administer IV fluids?
- Maintain patent IVC
- Counteract effects of anesthetic drugs
- Replace insensible losses
- Replace procedural losses
What are 6 concerns with peri-anesthetic fluid management?
- Hypovolemia
- Hypervolemia
- Anemia
- Hypoproteinemia
- Acid base and electrolyte abnormalities
- Abnormal glucose
What are 4 reasons hypoproteinemia is significant with anesthesia?
- Many anesthetic drugs are highly protein bound
- More drug available when protein levels are low, leads to more profound effects
- Low protein leads to loss of fluids from intravascular space
- Hypotension & pulmonary edema likely
What species is more prone to over-hydration?
Cats
What is the peri-anesthetic fluid rate for most dogs?
For cats?
- 10 mL/kg/hr
- 5 mL/kg/hr
Does redistribution of crystalloids happen quickly or slowly?
Quickly
How much crystalloid remains intravascular 15 minutes after infusion?
20-30%
Blood loss should be replaced with how much fluid?
3-4 times the volume of blood lost
Where do crystalloids get redistributed?
Interstitial space
Fluid has to be administered cautiously with what 3 conditions?
What is the dose lowered to?
- Cardiac disease
- Anuric renal failure
- Geriatric
- 2-5 mL/kg/hr
What can be used to treat anesthetic induced hypotension?
Fluid bolus
How much crystalloid can be given as a rapid bolus in addition to the continued hourly rate?
5-10 mL/kg over 15 minutes (or less)
The same amount as an hourly rate, but all given within 15 minutes.
How much is a shock rate fluid bolus?
1 blood volume/hour
What are 4 examples of fluid delivery set sizes?
- 10 drops/mL
- 15 drops/mL
- 20 drops/mL
- 60 drops/mL
Which size fluid delivery set is used in larger patients?
Smaller?
- Larger: 10 drops/mL
- Smaller: 60 drops/mL
Is it ok to bolus supplemented bags of fluids?
No
How much K+ can safely be given in an hour?
0.5 meq/kg/hr
What can be given in large volumes to expand ECF volume without changes in electrolyte composition?
What is the exception? Why?
- Crystalloids
- Saline: saline is not balanced
Which type of crystalloid is acidifying?
Normal saline (0.9% NaCl)
What type of cases may normal saline be a good choice for management in?
Chronic renal cases
What is an example of a balanced electrolyte solution (BES)?
Lactated Ringers Solution
What is the alkalinizing agent in LRS?
Lactate
What does LRS contain that one needs to be aware of if transfusing blood?
Calcium
Caution with LRS use should be used in what condition and in what species?
- Lactic acidosis
- Reptiles
What is a common choice for anesthetized patients?
LRS
What is the alkalinizing agent for Normosol-R and Plasmalyte 148?
Acetate
Normosol-R and Plasmalyte 148 may cause what with very rapid administration?
Vasodilation
Caution needs to be used with Normosol-R and Plasmalyte 148 in what type of patient?
Why?
- Diabetic ketoacidosis patients
- These fluids increase blood ketone concentrations
What is an example of a resuscitation crystalloid?
Hypertonic saline (7.5% NaCl)
Where does hypertonic saline draw fluid?
Into intravascular space
Hypertonic saline always has to be followed up with what?
Replacement crystalloid
What is the administration dose of hypertonic saline?
4 mL/kg IV
What is hypertonic saline used to increase?
ICP
The component of total osmotic pressure in plasma contributed by colloids is known as what?
Colloid osmotic pressure (oncotic pressure)
What are 3 uses for colloids?
- Correct hypovolemia
- Support colloid osmotic pressure
- Hypoproteinemic patients (TP
Oncotic pressure provided by colloids depends on what?
Number of particles
Duration of action of colloids depends on what?
Size of particles
What is the most commonly used synthetic colloid in vet medicine?
Vetstarch (hetastarch)
Hetastarch is metabolized by what?
What will this cause in the patient?
- Amylase
- Increase in amylase levels
What is the infusion rate of hetastarch?
2-5 mL/kg/hr
What is the maximum amount hetastarch that can be given per day?
Vetstarch?
- 20 mL/kg/day
- 40-50 mL/kg/day
What can too much start lead to?
Coagulopathies
What are 6 examples of negative effects that can be seen with hetastarch?
- Volume overload
- Coagulation
- Renal failure
- Hepatic failure
- Anaphylaxis
- Pruritus
What are 2 examples of colloid blood products?
- Plasma protein (FFP, whole blood)
- Lyophilized albumin
Plasma protein is used primarily for what?
Clotting factors
