Fluid Therapy Flashcards
What fraction of body fluid is ICF?
2/3
Extracellular Fluid is 1/3rd body fluid and comprises what structures?
Interstitial and Intravascular
Intracellular fluid has low/high Na+ and low/high K+
low Na+, high K+
Intravascular fluid when compared with interstitial fluid has high/low protein
high
What is the normal range for urinary losses
1500ml-2000ml per day
0.5-1.0mls/kg/hr
What is the normal Potassium requirement per day
0.5-1.0 mEq/kg/day
What is the normal Sodium requirements per day
1-2 mEq/kg/day
In 1L of N/S how many mEq of Na+ is there
154mEq, and 77mEq in a 500ml (the more commonly used bag at UHWI)
How much N/S and Potassium should be added for every litre of NG aspirate
1L N/S
10-20mEq K+
Do you administer supplementary potassium in the first 48 hrs post op ?
No
1) Hypovolemia causes aldosterone secretion and slat retention by kidney
2) potassium is released by damaged tissues
3) Potassium levels can also increase post blood transfusion
(Do not give K+ until the patient is passing adequate urine)
What is the maximum amount of potassium that can be safely administered in 500ml of N/S
20mEq
Q1-
In a 70 kg patient with normal U/Es and a daily urine output of 1500ml who also has NG losses of 2L what should the fluid replacement regime be?
Total vol. replaced: 4.5L
3L N/S, 1.5L D5W
60mEq of KCl
How much crystalloids should be given as replacement for every ml of blood lost, and why
3ml
This is because at least 2ml will move into the interstitial tissue and 1ml will remain intravascular
What is the formula for total fluid requiremnt?
Maintenance fluid + deficit + ongoing losses
List 4 types of ongoing losses
GI, Tubes/Drains, Third Spacing, Blood loss
Define crystalloids
These are solutions of crystalline solids in water
Why do you need to administer 3-4x the deficit when N/S is used to resuscitate a patient?
Because only 30% of the N/S administered actually remains in the intravascular component
Large volumes of N/S can lead to what metabolic complication
Hyperchloremic acidosis, since N/S has a higher concentration of Cl- ions than plasma
How can you avoid hyperchloremic metabolic acidosis when large volumes are required ?
Use balanced fluids such as Ringer’s LActate
What is the value, in mmol/L, of Na+ in Hartmann’s?
131
What is the value, in mmol/L, of Na+ in N/S
154
What is the value, in mmol/L, of Cl- in Hartmann’s
112
What is the value, in mmol/L, of K+ in Hartmann’s
5
What is the value, in mmol/L, of K+ in N/S
0
What is the value, in mmol/L, of Cl- in N/S
154
What is the fluid content of Lactated Ringer’s ?
Na+ = 131
K+ = 5
Cl- = 112
HCO3- =29
Ca2+= 4
What is the fluid content of N/S?
Na+= 154
K+ = 0
cl- = 154
HCO3- = 0
ca2+= 0
Why is N/S concidered an almost isotonic solution?
Because the conc. of Na+ and Cl- both exceed that of plasma
How many grams of glucose is in 1L of D5W
50g
How many calories is in 1 L of dextrose water?
200 calories= (50g x4)
Is D5W hypotonic or hypertonic solution?
hypotonic
Is N/S hypotonic or hypertonic solution?
isotonic (slightly hypertonic)
What is an indication for 5% dextrose, 0.2% saline?
Hypernatremic children (since the 1/5th n/s will have a dilutional effect on the Na)
Renal Impairment
What is the main indication for NaHCO3 8.5% sol. ?
Severe metabolic acidosis
What is the formula used to determine the necessary amount of NaHCO3
1/3 x body weight x base excess
What is the average dose of NaHCO3 when correcting acidosis
2-4 mls over 15 minutes
What are the clinical indications for mannitol
- raised ICP (due to cerebral edema)
-renal impairment
What are the indications for Hypertonic saline?
Dilutional Hyponatremia
- TURP syndrome
- SIADH secretion
Dilutional Hyponatremia
- TURP syndrome
- SIADH secretion
Can be corrected with which crystalloid
Hypertonic solution
- raised ICP (due to cerebral edema)
-renal impairment
can be corrected with which crystalloid
MAnnitol
What are colloids
These are suspensions of high molecular weight molecules
How are colloids classified
As synthetic or natural
and protein or non-protein
List 2 protein colloids
Albumin
Gelatin sol.List
2 non-protein colloids
hydroxyethol starch
Dextrans
List 2 natural colloids
Plasma
Albumin3
List 3 synthetic colloids
Gelofusine
Hydroxyethyl starch
Dextran
List 1 advantage and 1 disadvantage of colloids
Adv: stays in the intravascular component for up to 24hrs
Disad: large volumes can cause coagulopathy (Factor VII)
What is the infusion to blood loss ration for colloids
(Crystalloids 3mls:1ml blood lost)
1ml:1ml blood lost
What are some disadvantages of using Plasma in fluid therapy (3)
- may activate complement system
- increased risk of transfer of infections
- inc. risk of post traumatic multi-organ system failure
What is one advantage of using albumin in fluid therapy?
It is a free radical scavenger
What is one disadvantage of using albumin in fluid therapy?
It inhibits platelet aggregation and enhances the inhibition of factor xa by antithrombin II
List 6 complications of fluid thearpy
1)Volume overload
2)Electrolyte imbalance
3)Haemodilution&coagulopathy
4)hyper/hypoglycemia
5)anaphylactic reaction
6)complications of blood transfusion
What are the three grades for dehydration
Mild: 5-10%
Moderate: 10-15%
Severe: >20%
What are the normal plasma potassium levels
3.5 -5.0mEq/L
What method is used for calculating fluid requirements per hour
4, 2, 1 rule
4- first 10
2- 2nd 10
1- rest
