Fluid Management Flashcards
1
Q
anion gap
A
difference between cations and anions
Na+-(Cl-+HCO3-)
Normal = <12
>12 indicates pt has metabolic acidosis
2
Q
Respiratory acidosis results in…
A
- reduced myocardial contractility
- increased PVR
- decreased SVR
3
Q
Respiratory alkalosis results in…
A
- hypokalemia
- hypocalcemia
- dysrhythmias
- bronchoconstriction
- cerebrovasoconstricion
- hypotension
4
Q
Metabolic acisosis results in…
A
- reduced myocardial contractility
- increased PVR
- decreased SVR
5
Q
Metabolic alkalosis results in…
A
- hypokalemia
- hypocalcemia
- arrhythmias
- compensatory hypoventilation/hypercarbia
- reduced tissue oxygenation
6
Q
treatment of metabolic alkalosis
A
- expansion of intravascular volume
- administer K
- administer carbonic anhydrase inhibitor
7
Q
Base excess or deficit
A
- Used to measure deviation from normal bicarbonate level to help determine adequacy of intravascular volume
- 0 = normal bicarbonate level
- -2 to <0 = metabolic acidosis (base deficit)
- >0 to +2 = metabolic alkalosis (base excess)
8
Q
A
9
Q
Plasma solute concentrations
A
- Na: 140
- K: 4.3
- Mg: 2
- Cl: 105
- HCO3-: 24
- phosphate: 2
- Protein: 1
- Total Osm: 291
- pH: 7.4
10
Q
ECF solute concentrations
A
- Na: 140
- K: 4.3
- Mg: 2
- Cl: 105
- HCO3-: 24
- phosphate: 2
- protein: 0
- Total Osm: 290
- pH: 7.4
11
Q
ICF solute concentrations
A
- Na: 12
- K: 120
- Mg: 40
- Cl: 5
- HCO3-: 12
- Phosphate: 100
- protein: high
- Total osm: 290
- pH: 7.2
12
Q
sources of intra-op fluid requirements
A
- maintenance
- healthy adults require 2.5L/day over 24 hours
- fluid deficit
- Blood loss
- evaporative loss
- 3rd space loss
13
Q
calculating maintenance fluids
A
- 4-2-1 rule
- 4 ml/kg/hr for first 10 kg
- 2 ml/kg/hr for second 10 kg
- 1 ml/kg/hr for each additional kg
14
Q
Fluid deficit
A
- the maintenace requirement multiplied by the number of hours pt was NPO
- if receiving maintenace IVF, no NPO deficit
- if baseline hypovolemia exists, consider the overall deficit greater than just NPO deficit
- replace fluid to restore MAP, HR and filling pressures BEFORE induction
15
Q
Fluid deficit replacement strategy
A
- 1/2 of deficit replaced during first hour of surgery
- 1/4 of deficit replaced during second hour of surgery
- 1/4 of deficit replaced during third hour of surgery
16
Q
Blood loss estimations
A
- soaked gauze 4x4 = 10 ml
- soaked laparotomy pads = 100-150 ml
- suction containers
- floor and drapes
- consider if gauze and pads are being used wet or dry by surgeon
17
Q
floor spill approximations
A
- 1 inch diameter = 5ml
- 2 inch diameter = 20 ml
- 3 inch diameter = 45 ml
- 4 inch diameter = 80 ml
18
Q
Estimated blood volume
A
- neonates
- premie = 95 ml/kg
- term = 85 ml/kg
- infant = 80ml/kg
- child = 70 ml/kg
- adult
- men = 75 ml/kg
- women = 65 ml/kg
19
Q
allowable blood loss
A
ABL = (EBV x (starting HCT - allowable HCT))/ starting HCT
*helps anesthetist plan when to transfuse patient
20
Q
Evaporative loss
A
- evaporative loss is directly related to amount of surface area of surgical wound and duration of exposure
21
Q
3rd space loss
A
due to fluid shifts and intravascular volume deficit caused by redistribution of fluids
Ex. trauma, infection, burns, ascites
22
Q
Replacing evaporative and 3rd space losses
A
- short, superficial procedure = 0-2ml/kg/hr
- moderate, uncomp untra-abd, orthopedic = 3-5 ml/kg/hr
- Severe, long, invasive = 6-9 ml/kg/hr
- Emergency, mult injuries = 10-15 ml/kg/hr
23
Q
Blood loss replacement
A
- 3:1 crystalloid for blood
- 1:1 blood/colloid for blood
24
Q
ERAS
A
- enhanced Recovery after surgery
- fluid philosophy of avoidance of sodium and water overload
- carboloading pre-op
- maintain normothermia
- avoid opioids
- **questioning science behind replacement of 3rd space losses
25
Goal directed fluid therapy
* using advanced monitoring to make estimations of functional circulating volume
* is the patient going to respond to fluid?
* stroke volume variation
* pulse pressure variation
* systolic pressure variation
26
Frank Starling curve
27
hypotonic solutions
* Osm 253
* replaces water loss
* called "maintenance fluids"
* not used in OR
* Example: D5W
* water moves into ISF and cells
28
isotonic solutions
* osm 300
* replaces water and electrolyte loss
* called replacement fluids
* used in OR
* ex: LR, NS
29
hypertonic solutions
* D5 1/2 NS osm (432), 3% NS osm (1026)
* for hyponatremia or shock
* draws fluid into intravascular space
30
LR facts
* NS with electrolytes (K+, Ca++) and buffer (lactate)
* isotonic (275)
* provides 100 ml free water per liter of solution
* tends to lower Na+
* lactate gets converted to bicarb
* solution most similar to ECF
* avoid in ESRD b/c it contains K+
* do not mis with PRBC as the Ca++ binds to citrate in blood
31
LR electrolytes
* Na+ 130 mEq/L
* K+ 4 mEq/L
* Ca++ 3 mEq/L
* Cl- 110 mEq/L
* lactate 28 mEq/L
* glucose 0g/L
* pH 6.5
32
Normal saline facts
* 0.9% NaCl in water
* isotonic: osm 308
* in large volume produces high Cl- content which leads to dilutional hyperchloremic acidosis
* preferred solution for diluting PRBCs
33
0.9% NS electrolytes
* Na+ 154 mEq/L
* K+ 0 mEq/L
* Ca++ 0 mEq/L
* Cl- 154 mEq/L
* lactate 0 mEq/L
* glucose 0 g/L
* pH 6.0
34
Normosol-R electrolytes
* Na+ 140 mEq/L
* K+ 5 mEq/L
* Ca++ 0 mEq/L
* Cl- 98 mEq/L
* glucose 0 g/L
* Mg++ 3 mEq/L
* Acetate 27 mEq/L (buffer)
* gluconate 23 mEq/L
* pH 7.4
35
D5W
* hypotonic solution: osm 260
* rarely used perioperatively
* causes free water intoxication and hyponatremia
* provides 170-200 calories/1000 ml for energy
* can cause hyperglycemia
* except in DM pt receiving insulin or neonate
36
3% NaCL
* Na/Cl 513 mEq
* used rarely for low volume resuscitation
* mostly used to treat hyponatremia
* risk of hyperchloremia, hypernatremia, and cellular dehydration
37
Colloid solutions
* onsmotically active
* stay intravascular 3-16 hours while crystalloid stays about 15 minutes
* high molecular weight
* volume administered is equivalent to fluid/blood lost from intravascular volume
38
albumin
* obtained from fractionated human plasma
* possible to have reaction
* does not contain coagulation factors or blood group antibodies
* available as 5% or 25%
* size of molecule, which determines different oncotic pressures
* 5% solution common in OR
* 5% solutions causes oncotic pressure of 20
39
Dextran
* Synthetic colloid
* water soluble glucose polymers that get enzymatically degraded to glucose
* might have to give extra insulin
* Dextran 70- used for volume expansion
* draws fluid in from ISF
* Dextran 40- used for prevention of thrombosis
* decreases viscoscity of blood
40
Dextran side effects
* anaphylactoid reaction
* platelet inhibition
* noncardiac pulmonary edema
* inerference with crossmatching
41
Hetastarch
| (Hespan 6%)
* synthetic colloid
* as effective as albumin for volume expansion
* nonantigenic- does not create immune response
* cheaper than albumin
* stored in reticuloendothelial system for several hours and renally excreted
* **max dose: \<20 ml/kg/day** because it pulls SO much fluid from cells
* oncotic pressure 30
42
indications for blood transfusions
* expand intravascular volume
* \*increase oxygen carrying capacity
* hemoglobin and hematocrit
* rarely if HGB \> 10
* definitely if HGB \<6
* if between, depends on pts risk for complications and inadequate oxygenation
* use of "trigger" not recommended
43
risks of blood product administration
1. Hepatitis B or C
2. HIV
3. Bacterial sepsis
4. allergic reactions/febrile reactions
5. lung injury
6. hemolytic reactions
7. noncardiogenic pulmonary edema
8. acute hypotensive transfusion reaction
44
PRBCs facts
* Type and Rh factor is sufficient for most people to be compatible
* 1 unit PRBC increases HGB 1 gm/dl
* HCT of one unit is 70%
* decreases as the PRBCs age
45
PRBCs reconstituted with:
* 0.9% NS
* 5% dextrose in 0.4% NS
* 5% dextrose in 0.9% NS
* Normosol-R
46
PRBC citrate toxicity
* citrate binds to Ca++, causes hypocalcemia
* monitor ionized calcium
47
complications of autologous blood
1. anemia
2. pre-op myocardial ischemia from the anemia
3. administration of the wrong unit
4. need for more frequent blood transfusion
5. febrile and allergic reaction
48
Platelet facts
* one unit comes from centrifuging single unit of whole blood
* volume 200-400 ml
* one unit increases platelet count 7,000-10,000 one hour after transfusion
* incidense of platelet related sepsis is 1 in 12,000
* bacterial contamination risk 1:2,000
49
Platelet uses
1. thrombocytopenia
2. dysfunctional platelets
3. active bleeding
4. platelet count \<50,000
50
FFP facts
* contains clotting factors and plasma proteins
* volume 200-250 ml
* must be ABO compatible
* each unit increases each clotting factor level by 2-3%
51
FFP uses
1. urgent reversal of warfarin
2. know coagulation factor deficiencies
3. correction of microvascular bleeding when PT or PTT is increased
4. correction of microvascular bleeding in a pt transfused with more than one blood unit when PT and PTT cannot be obtained in timely fashion
52
cryoprecipitate facts
* the last thing to consider transfusing
* derived from precipitate remaining after FFP is thawed
* ABO compatible
* administer rapidly through filter 200 ml/hr, complete within 6 hours
53
cryoprecipitate contents
1. factor VII
2. fibrinogen
3. vWF
4. XIII
54
Cryoprecipitate uses
1. von Willebrand's disease
2. fibrinogen deficiencies
