Pharmacologic Response to CPB- Exam 3 Flashcards Preview

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Flashcards in Pharmacologic Response to CPB- Exam 3 Deck (124):
1

Pharmacokinetics

What the body does to the drug

2

Pharmacodynamics

How a drug interacts with the body to produce its effects

3

First order kinetics

elimination of a drug occurs at a constant fraction of drug remaining in the body per unit of time

4

Zero order kinetics

when drug administration exceeds the body's ability to clear it, leading to drug accumulation

5

To prevent drug accumulation, what should be done?

Drug infusion rates should be adjusted according to patient response

6

To prevent drug accumulation, what should be done?

Drug infusion rates should be adjusted according to patient response

7

Changes in Pharmacokinetics due to CPB

Hemodilution
Hypothermia
Perfusion
Acid-Base Status
Sequestration

8

Changes in Pharmacokinetics due to CPB

Hemodilution
Hypothermia
Perfusion
Acid-Base Status
Sequestration

9

Hemodilution

Reduction in circulating protein concentration
Reduction in RBC concentration
Reduction in concentration of free drug (unless your pump prime matches exactly)
Alterations in organ blood flow, affecting distribution and clearance

10

Hemodilution

Reduction in circulating protein concentration
Reduction in RBC concentration
Reduction in concentration of free drug (unless your pump prime matches exactly)
Alterations in organ blood flow, affecting distribution and clearance

11

What happens if you add drugs to your prime BEFORE RAP? or AFter RAP?

Lose some when you rap
most of the time you wont have time to add drugs after you rap
usually you'll go on pump right after you rap

12

What happens if you add drugs to your prime BEFORE RAP? or AFter RAP?

Lose some when you rap
most of the time you wont have time to add drugs after you rap
usually you'll go on pump right after you rap

13

Hypothermia

Fluid shifts from intravascular to interstitial space
(altered volume of distribution, increased 3rd spacing)
Vasoconstriction (changes in organ perfusion)
Reduction in enzyme-mediated biotransformation
increased solubility of volatile anesthetics

14

Hypothermia

Fluid shifts from intravascular to interstitial space
(altered volume of distribution, increased 3rd spacing)
Vasoconstriction (changes in organ perfusion)
Reduction in enzyme-mediated biotransformation
increased solubility of volatile anesthetics

15

What are two important things to keep in mind regarding patient during perfusion?

Lungs excluded form circulation (valium, propofol, opioids)
Altered hepatic blood flow - vasoconstriction (fentanyl, propofol)

16

What are two important things to keep in mind regarding patient during perfusion?

Lungs excluded form circulation (valium, propofol, opioids)
Altered hepatic blood flow - vasoconstriction (fentanyl, propofol)

17

Acid Base Status

Altered organ blood flow (ph stat= increase cerebral blood flow)
altered ionization and protein binding

18

Sequestration

Drugs may be taken up by various components of the CPB circuit
-coated tubing
-oxygenators
-hemofilters (many factors influence the movmement of drug across the membrane; degree of protein binding is a major determinant)

19

When administering medications

Ensure you have physician's order or standing protocol authorizing you to administer the medication

The patient is not allergic to the medication
you should have the correct medication, the correct concentration and the correct dosage

Inspect the medication for expiration date, precipitates and sterility

20

When administering medications

Ensure you have physician's order or standing protocol authorizing you to administer the medication

The patient is not allergic to the medication
you should have the correct medication, the correct concentration and the correct dosage

Inspect the medication for expiration date, precipitates and sterility

21

What is in your drug box?

Heparin
Neo-Synephrine
NaHCO3
Lidocaine
MgSO4
Calcium
Potassium
Mannitol

22

What is heparin sodium derived from?

Bovine lung tissue or porcine mucosa standardized for anticoagulant activity

23

How is the potency of heparin sodium determined?

By biological assay using a USP reference standard based on units of heparin activity per milligram

24

Units/Mg Heparin Conversation

100 units = 1 mg
Ex. 5,000 units = 50 mg

25

What is the action of heparin sodium?

Stops coagulation by potentiating antithrombin III and inhibiting the action of activated Factors IX and XI

26

What is the action of heparin sodium?

Stops coagulation by potentiating antithrombin III and inhibiting the action of activated Factors IX and XI

27

How is heparin eliminated?

kidneys

28

What is the half-life of heparin?

At CPB doses is 2 or more hours; prolonged by hypothermia and renal blood flow alterations

29

What is the half-life of heparin?

At CPB doses is 2 or more hours; prolonged by hypothermia and renal blood flow alterations

30

Heparin Side Effects

Activation of t-PA and platelets
Boluses decrease SVR by 10-20%
Anaphylaxis rarely occurs
HIT and HITT

31

Heparin Loading Dose

300-450 units/kg
Rarely needs to exceed 35,000 to 40,000 units

32

How does heparin distribute?

Primarily in plasma, so increasing dose with increasing body weight is only relevant to a certain point

33

How does heparin distribute?

Primarily in plasma, so increasing dose with increasing body weight is only relevant to a certain point

34

What concentration of heparin should be added to prime?

Priming solution should contain heparin at approx the same concentration of the patient's blood stream

35

What prolongs the ACT?

Hypothermia, and hemodilution

36

What is target ACT?

Controversial (300 to 480 seconds)

37

Most vials you will see for adult CPB will be what concentration?

1000 units/ mL

Ex. Loading dose: 30,000 units
30,000 units x 1mL/1000units = 30 mL

38

Neo-Synephrine Action

Synthetic selective alpha 1- adrenergic agonist that causes vasoconstriction in arterioles

39

Neo-Synephrine Duration

Less than 5 minutes

40

How is Neo dosed?

Titrated to effect

41

What should you always do when giving neo?

Start with a test dose

42

Neo-Synephrine Dosing

IV bolus:
100 ug/mL
200 ug/mL
400 ug/mL

IV infusion:
10 or 15 mg in 250 mL IV fluid (40-60 ug/mL)

43

Neo-Synephrine Dosing

IV bolus:
100 ug/mL
200 ug/mL
400 ug/mL

IV infusion:
10 or 15 mg in 250 mL IV fluid (40-60 ug/mL)

44

How many mg typically in Phenylephrine vial?

10 mg Phenylephrine in 1 mL vial

45

How many mg typically in Phenylephrine vial?

10 mg Phenylephrine in 1 mL vial

46

Sodium Bicarbonate

A sterile, nonpyrogenic, hypertonic solution of sodium bicarbonate (NaHCO3) in water for injection for administration by the intravenous route as an electrolyte replenisher and system alkalizer

Also used to treat hyperkalemia

47

NaHCO3 Dosing

Dose (mEq) = 0.3 x Weight (kg) x BD (mEq/L)
*Or just "1 amp" (50 mEq)

48

NaHCO3 Dose for Hyperkalemia

Adults: 50 mEq
Peds: 1-2 mEq/kg

49

Lidocaine Action

reduces cell membrane permeability for sodium and potassium which increases the stimulation thresholds in ventricles

50

Lidocaine Site of Action

cell membrane

51

Lidocaine Duration of Action

15-30 minutes post bolus

52

Lidocaine Dosing

IV bolus: 1-2 mg/kg
Usually 100 to 200 mg bolus at XC removal
Not to exceed 300 mg/h r

53

Magnesium Sulfate Action

Controls transmembrane electrolytes and energy metabolism; cardiac arrythmias may occur during hypomagnesemia

54

What is heparin sodium derived from?

Bovine lung tissue or porcine mucosa standardized for anticoagulant activity

55

When can hypomagnesemia occur during CPB?

Poor pre op health
Albumin administration
Citrated blood product administration

56

MgSO4 Dosing

2 to 2.5 g initial bolus
1.75 g/hr infusion

57

MgSO4 Dosing on CPB

usually given as 2 to 4 grams at XC removal with lidocaine
Often 0.5 g/L concentration

58

Calcium Chloride Action

Involved in myocardial contractility, blood clotting, neurotransmission and muscle contraction
May be used for mixing with thrombin for platelet gel
Levels drop during CPB; may be necessary to replenish before coming off CPB; especially if citrated blood products are given

59

CaCl2 Dosing

200 to 1000 mg slow IV
Often 100mg/mL concentration
Given post XC removal and before termination of CPB if levels are low

60

Hyperkalemia CaCl2 Dosing

Adults: 0.5-1g CaCl2
Peds: 20 mg/kg Calcium Gluconate

61

Hyperkalemia CaCl2 Dosing

Adults: 0.5-1g CaCl2
Peds: 20 mg/kg Calcium Gluconate

62

Potassium Chloride

The major intracellular ion
Necessary for normal cardiac contractions
Hyperkalemia more of an issue than hypokalemia (cardiopleigia)

63

Potassium Chloride

The major intracellular ion
Necessary for normal cardiac contractions
Hyperkalemia more of an issue than hypokalemia (cardiopleigia)

64

KCl Dosing for Cardioplegia

15-30 mmol/L of solution delivered into the heart
i.e. 4 to 1 cdpg requires 5 times the delivery strength in the cardioplegia bag

65

KCl Dosing for Hypokalemia

Dose (mEq) = weight (kg) x 0.3 x K+ deficit

66

KCL Usual concentration

2 mEq/L
Give it slowly especially if XC not on

67

KCL Usual concentration

2 mEq/L
Give it slowly especially if XC not on

68

Mannitol Action

Osmotic diuretic prevents reabsorption in the proximal tubule (also thought to be a free radical scavenger)

69

Mannitol Action

Osmotic diuretic prevents reabsorption in the proximal tubule (also thought to be a free radical scavenger)

70

Mannitol Dosing

During CPB 0.5 to 1.0 g/kg
Often given as 12.5 g vials in prime or during warming

Inspect carefully for precipitate or cystals
Use a filtered needle during administration

71

What else is in your drug box?

THAM
Amicar
Trasylol
Thrombate III
Benadryl
Solu-Medrol
Dextrose
Albumin
Insulin
Forane

72

THAM

tromethamine

73

THAM Action

Creates an alkaline environment by combining with hydrogen ions to form bicarbonate

74

THAM Dosing

Each 100 mg contains tromethamine 3.6 g (30mEq)
Dose (mL) = wt (kg) x Base deficit (mEq/L) x 1.1

75

THAM Dosing

Each 100 mg contains tromethamine 3.6 g (30mEq)
Dose (mL) = wt (kg) x Base deficit (mEq/L) x 1.1

76

Amicar

Aminocaproic acid

77

Amicar Action

Inhibits plasminogen activators to prevent conversion to plasmin
Reduces bleeding cased by hyperfibrinolysis

78

Amicar Dosing

Loading Dose: 5g IV
Infusion: 1 - 1.25g/hr (30 g/day max)

79

Trasylol Action

Inhibits fibronlysis and turnover of coagulation factors (serine protease inhibitor)

80

Trasylol Action

Inhibits fibronlysis and turnover of coagulation factors (serine protease inhibitor)

81

Trasylol Dosing Test Dose

1 mL at least 10 min before dosing

82

Trasylol Dosing Loading Dose

200 mL (280 mg) over 20-30 min

83

Trasylol Dosing Infusion dose

50 mL/hr

84

Trasylol Dosing Pump Prime Dose

200 mL

85

What's important to remember about trasylol?

may artificially prolong act results

86

What's important to remember about trasylol?

may artificially prolong act results

87

Thromate III (antithrombin) Action

inactivates thrombin and activated forms of clotting factors IX, X, XI, and XII which results in inhibition of coagulation

The anticoagulant effect of heparin is enhanced with thrombate III in patients with antithrombin III (AT-III) deficiency

88

Thrombate III Dosing

Dose (IU)= (desire-baseline AT-III level) x Kg / (1.4)

89

Each vial of thromate III will contain how many units?

500 units

90

You should use Thrombate III within how many hours of reconstitution?

within 3 hours

91

Benadryl Action

antihistamine, sedative, antiemetic, anticholinergic
Given on CPB after suspicion of allergic reaction

92

Benadryl Dosing

10-50 mg

93

Solu-Medrol Generic Name

methylprenisolone

94

Solu-Medrol Action

Intermediate acting glucocorticoid used on bypass to combat inflammation, often during circulatory arrest cases
may cause hyperglycemia

95

Solu-Medrol Dosing

125 mg - 1g
Sterile powder which must be mixed with the accompanying diluent

96

Solu-Medrol must be used within how many hours of mixing?

48 hours

97

What are some examples of inhalation anesthetics?

Halothane
Isoflurane
Sevorflurane

98

Forane Action

ethers that modulate the GABA (A) receptor, use for induction and maintenance of anesthesia
Potent vasodilators
Pungent odor

99

Forane Dosing

Bottle must be used with appropriate adapter to fill forane vaporizer on your pump; spillage can cause structural degradation of plastic

Scavenge oxygenator gas outflow when using anesthetic gas

100

Set Vaporizer of forane at what percent after initiation of gas flow?

0.5 % to 2% ; can be temporarily increased for blood pressure control

101

Set Vaporizer of forane at what percent after initiation of gas flow?

0.5 % to 2% ; can be temporarily increased for blood pressure control

102

AmSECT Standard for Scavenging Gases

Standard 6.8: An anesthetic gas scavenge line shall be employed whenever inhalation agents are introduced into the circuit during CPB procedures

103

AmSECT Standard for Scavenging Gases

Standard 6.8: An anesthetic gas scavenge line shall be employed whenever inhalation agents are introduced into the circuit during CPB procedures

104

Short Term Anesthetic Gas Exposure

Liver and kidney disease
Headache
Irritability
Fatigue
Nausea
Drowsiness
Compromised performance
-Decreased vigilance
-Slow reaction time

105

Low Term Anesthetic Gas Exposure

Miscarriage
Genetic damage
cancer
miscarriage and birth defects in the spouses of exposed workers

106

Low Term Anesthetic Gas Exposure

Miscarriage
Genetic damage
cancer
miscarriage and birth defects in the spouses of exposed workers

107

What are the three approaches to scavenging gases?

1. Nothing (adequate that air is being circulated)
2. Active ventilation system
3. Passive ventilation system

108

What is one more approach to gas scavening?

Suction tubing attached to oxygenator gas outflow
-with tiny holes cut into it
-with a 1/4'' x 1/4'' x 1/4'' Y connector on it
Attached to wall suction or waste suction set at - 100 mmHg

109

Albumin

Concentration of proteins derived from human blood
Increases plasma volume or serum albumin levels
May not be consented for by jehovah's witnesses patients

110

Albumin Concentrations

Varying concentrations 5%, 20%, 25%
-25% contains 250 g of protein for every 1000 mL

111

Albumin will increase circulating volume how much?

3.5 x the volume injected, in an adequately hydrated individual

112

Albumin Dosing in Prime

12.5 to 25 g in prime, or as needed

113

Most vials you will see for adult CPB will be what concentration?

1000 units/ mL

Ex. Loading dose: 30,000 units
30,000 units x 1mL/1000units = 30 mL

114

What should you always do when giving neo?

Start with a test dose

115

Sodium Bicarbonate

A sterile, nonpyrogenic, hypertonic solution of sodium bicarbonate (NaHCO3) in water for injection for administration by the intravenous route as an electrolyte replenisher and system alkalizer

Also used to treat hyperkalemia

116

Magnesium Sulfate Action

Controls transmembrane electrolytes and energy metabolism; cardiac arrythmias may occur during hypomagnesemia

117

Serum Albumin

118

Insulin Action

stimulates glucose utilization by muscle nad fat, and acts on the liver to inhibit glycogenolysis and gluconeogenesis

119

Insulin Action

stimulates glucose utilization by muscle nad fat, and acts on the liver to inhibit glycogenolysis and gluconeogenesis

120

Glucose Target Range During Cardiac Surgery

110-180 mg/dL

121

Insuling Dosing

Very anesthesia and hospital protocol dependent

100 u/mL
10-20 units IV on CPB
Never shake vial, roll in your hands to mix
Use 1 mL syringe or dedicated insulin syrgine

122

Insulin Dosing for Hyperkalemia

Adults: 25 g Dextrose + 10 units INsulin
Peds: 1-2 g/ kg Dextrose + 0.3 units Insulin per gram of Dextrose

123

Dextrose D-50

Concentrated carbohydrate in the form of dextrose in water used to treat hypoglycemia

124

Dextrose Dosing

10-25g