Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NAPLEX Review > Calculations IV > Flashcards

Calculations IV Flashcards

1
Q

What is body mass index (BMI)?

A

Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is BMI a useful measure of?

A

Body fat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the limitations of BMI?

A

BMI can over-estimate body fat in persons who are muscular, and can under-estimate body fat in frail elderly persons and others who have lost muscle mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In terms of waist circumference, what waist size is associated with higher disease risk?

A

High risk is defined as a waist size > 35 inches for women or > 40 inches for men

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the formula for BMI?

A

weight (kg)/[height (m)]^2 or weight (pounds)/[height (in)]^2 x 703

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What BMI is considered underweight?

A

< 18.5 kg/m2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What BMI is considered normal weight?

A

18.5 - 24.9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What BMI is considered overweight?

A

25-29.9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What BMI is considered obese?

A

> 30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the three potential measures of body weight for a patient?

A

Actual (or total) body weight, ideal body weight and adjusted body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is actual body weight or total body weight?

A

Actual body weight or total body weight is the weight of the patient when weighed on a scale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is ideal body weight?

A

Ideal body weight is the healthy (ideal) weight for a person

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do you calculate IBW for males?

A

50 kg + (2.3 kg)(number of inches over 5 feet)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do you calculate IBW for females?

A

IBW (females) = 45.5 kg + (2.3 kg)(number of inches over 5 feet)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is adjusted body weight?

A

Adjusted body weight is calculated when patients are obese or overweight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the formula to calculate adjusted body weight?

A

IBW + 0.4(TBW - IBW)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If a person is underweight, what measure of body weight do you use?

A

Use total body weight for all medications

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

If a person is normal weight, what measure of body weight do you use?

A
  • Use total body weight for most medications

- Use ideal body weight for aminophylline, theophylline, acyclovir and levothyroxine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

If a person is obese, what measure of body weight do you use?

A
  • Use ideal body weight for aminophylline, theophylline, acyclovir and levothyroxine
  • Use total body weight for LMWHs, UFH and vancomycin
  • Use adjusted body weight for aminoglycosides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are flow rates?

A

Flow rates are used to specify the volume or amount of drug a patient will receive over a given period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are examples of how flow rate can be expressed?

A

Milliters per hour, milligrams per hour, mcg/kg/min or as the total time to administer the entire volume of the infusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does flow rate depend on?

A

Flow rate depend on the dose of the medication and the concentration available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is creatinine?

A

Creatinine is a breakdown product when muscle tissue makes energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the normal range for serum creatinine?

A

The normal range for serum creatinine is approximately 0.6-1.3 mg/dL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What happens to creatinine when kidney function declines?

A

If kidney function declines and creatinine cannot be cleared, the creatinine levels will increase in the blood and the creatinine clearance with decrease

*Concentration of drugs that are renally cleared will also increase and a dose reduction may be required

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What should be assessed when a patient is dehydrated?

A

Patients should be assessed for dehydration when the serum creatinine is elevated because dehydration can cause both the serum creatinine (SCr) and the blood urea nitrogen (BUN) to increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the BUN:SCr ratio that indicates dehydration?

A

> 20:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are some signs of dehydration?

A

Signs of dehydration can include decreased urine output, tachycardia, tachypnea, dry skin/mouth/mucous membranes, skin tenting (skin does not bounce back when pinched into a fold) and possibly fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What can usually cause dehydration?

A

Dehydration is usually caused by diarrhea, vomiting and/or a lack of adequate fluid intake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the Cockgroft-Gault equation?

A

CrCl (mL/min) = ([140 - (age of patient)]/[72 x SCr]) x weight in kg (x 0.85 if female)

*formula used to estimate renal function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

When is the Cockcroft-Gault equation unreliable?

A

It is not reliable in very young children, ESRD patients or when renal function is fluctuating rapidly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

If a patient underweight, what body weight measure should be used for calculating CrCL?

A

Total body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

If a patient normal weight, what body weight measure should be used for calculating CrCL?

A

Ideal body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

If a patient overweight or obese, what body weight measure should be used for calculating CrCL?

A

If BMI < 25, use ideal body weight. If BMI > 25, use adjusted body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is pH?

A

The pH refers to the acidity or basicity of a solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What does an increase or decrease in pH represent?

A

As a solution becomes more acidic (the concentration of proton increases), the pH decreases. When the concentration of protons decrease, the pH increases and the solution is more basic, or alkaline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How can the acid-base status of. patient be determined?

A

The acid-base status of a patient can be determined with an arterial blood gas (ABG)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is the primary buffering system of the body?

A

The bicarbonate/carbonic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What organ helps maintain neutral pH?

A

The kidneys help to maintain a neutral pH by controlling bicarbonate reabsorption and elimination

40
Q

What is the role of bicarbonate in the body?

A

Bicarbonate acts as a buffer and a base

41
Q

How does the lungs help maintain a neutral pH?

A

The lungs help maintain a neutral pH by controlling carbonic acid (which is directly proportional to the partial pressure of carbon dioxide or pCO2) retain or released from the body

42
Q

What is the role of carbon dioxide in the body?

A

Carbon dioxide acts as a buffer and an acid

43
Q

What is acidosis?

A

An acid-base disorder that leads to a pH < 7.35

44
Q

What is alkalosis?

A

If the disorder leads to a pH > 7.45

45
Q

What is the primary disturbance in a metabolic acid-based disorder?

A

The primary disturbance in a metabolic acid-base disorder is the plasma HCO3 concentration

46
Q

How is metabolic acidosis categorized?

A

A metabolic acidosis is characterized primarily by a decrease in plasma HCO3 concentration

47
Q

How is metabolic alkalosis characterized?

A

In a metabolic alkalosis, the plasma HCO3 concentration is increased

48
Q

What is metabolic acidosis associated with?

A

Metabolic acidosis may be associated with an increase in the anion gap

49
Q

What is the primary disturbance in a respiratory acid-base disorder?

A

The primary disturbance in a respiratory acid-base disorder is pCO2

50
Q

How is respiratory acidosis characterized?

A

In respiratory acidosis, the pCO2 is elevated

51
Q

How is respiratory alkalosis characterized?

A

In respiratory alkalosis, the pCO2 is decreased

52
Q

What is the reference range of pH?

A

7.35 - 7.45

53
Q

What is the reference range for pCO2?

A

35 - 45 mmHg

54
Q

What is the reference range for pO2?

A

80 - 100 mmHg

55
Q

What is the reference range for HCO3?

A

22 - 26 mEq/L

56
Q

What is the reference range for O2 sat?

A

> 95%

57
Q

How are ABGs presented in a written chart note?

A

ABG: pH/pCO2/pO2/HCO3/O2 sat

58
Q

What is the anion gap?

A

The anion gap is the difference in the measured cations and the measured anions in the blood

59
Q

What are the possible causes of metabolic acidosis?

A

Cyanide, uremia, toluene, ethanol (alcoholic ketoacidosis), diabetic ketoacidosis, isoniazid, methanol, propylene glycol, lactic acidosis, ethylene glycol, salicylates

60
Q

When is the anion gap considered high?

A

> 12 mEq/L

61
Q

How is the anion gap calculated?

A

Anion gap (AG) = Na - Cl - HCO3

62
Q

What is the role of buffer systems?

A

Buffer systems help to reduce the impact of too few or too many hydrogen ions in body fluids. Buffers minimize fluctuations in the pH so that harm is avoided

63
Q

What could the under or overproduction of hydrogen ions do?

A

These hydrogen ions could cause harm, including degrading some drugs, destabilizing proteins, inhibiting proteins, inhibiting cellular functions and, with too much of a change outside of the narrow change, cells die and death can occur

64
Q

What are buffer systems composed of?

A

Buffer systems are composed of either a weak acid and salt of the acid or a weak base and a salt of the base

65
Q

What is an acid?

A

An acid is a compound that dissociates, releasing (donating) protons into solution

*Once the proton is released, the compound is now a conjugate base, or its salt form

66
Q

What is a base?

A

A base picks up, or binds, the proton

67
Q

How are acid-base reactions equilibrium reactions?

A

There is drug moving back and forth between the acid and base state

68
Q

What can be used to determine if the drug is acting as an acid or base?

A

The pH and pKa

69
Q

What does it mean when pH = pKa?

A

When the pH = pKa, the molar concentration of the salt form and 50% in acid form. When the pH = pKa, this is the point at which half of the compound is not protonated (ionized), and half is protonated (un-ionized)

70
Q

What does it mean when there is a strong acid or base?

A

A strong acid or base means 100% dissociation

71
Q

What does it mean when there is a weak acid or base?

A

A weak acid or base means very limited dissociation

72
Q

What does it mean when pH > pKa?

A

If the pH > pKa, more of the acid is ionized, and more of the conjugate base is un-ionized

73
Q

What does it mean when pH = pKa?

A

If the pH = pKa, the ionized and un-ionized forms are equal

74
Q

What does it mean when pH < pKa?

A

If the pH < pKa, more of the acid is un-ionized, and more of the conjugate base is ionized

75
Q

Why is the percentage of drug in the ionized vs. un-ionized state important?

A

An ionized drug is soluble but cannot easily cross lipid membranes. An un-ionized drug is not soluble but can cross the membranes and reach the proper receptor site. Most drugs are weak acids so they are soluble and can pick up a proton to cross the lipid bilayer

76
Q

What is the purpose of Henderson-Hasselbalch equation?

A

It is used to solve for the pH

77
Q

What is the weak acid formula?

A
78
Q

What is the weak acid formula?

A

pH = pKa + log [salt/acid]

79
Q

What is the weak base formulas?

A

pH = (14 - pKb) + log [base/salt] = pKa + log [base/salt]

80
Q

How do you calculate the percent ionization of a weak acid?

A

% ionization = 100 / [1 + 10^(pKa - pH)]

81
Q

How do you calculate the percent ionization of a weak base?

A

% ionization = 100 / [1 + 10^(pH - pKa)]

82
Q

Describe calcium carbonate

A

Calcium carbonate has acid-dependent absorption and should be taken with meals. It is a dense form of calcium and contains 40% elemental calcium

83
Q

Describe calcium citrate.

A

Calcium citrate has acid-independent absorption and can be taken with or without food. It is less dense and contains 21% elemental calcium

84
Q

What is calcium acetate used for?

A

Calcium acetate is used as a phosphate binder and not for calcium replacement

*Though the capsules contain 25% elemental calcium, absorption from this formulation is poor

85
Q

How is aminophylline and theophylline dosed?

A

They are dosed using IBW in normal weight and obese patients for safety

86
Q

How do you convert from aminophylline to theophylline?

A

Multiply by 0.8

87
Q

How do you convert from theophylline to aminophylline?

A

Divide by 0.8

88
Q

What happens when a patient’s neutrophil count is low?

A

The lower a neutrophil’s count, the more susceptible that patient is to infection

89
Q

What is the Clozapine REMS programs designed for?

A

The Clozapine REMS Program is designed to reduce the risk of severe clozapine-induced neutropenia; clozapine cannot be refilled if the ANC is < 1000 cells/mm^3

90
Q

If a patient is neutropenic, what are some monitoring parameters?

A

A neutropenic patient should be monitored for signs of infections, including fever, shaking, general weakness or flu-like symptoms. Precautions to reduce infection risk, such as proper hand-washing and avoiding others with infection, should be followed

91
Q

What is normal ANC levels?

A

2200 - 8000

92
Q

What is neutropenia levels?

A

< 1000 (at risk for infection)

93
Q

What is severe neutropenia levels?

A

< 500

94
Q

What is profound neutropenia levels?

A

< 100

95
Q

How do you calculate ANC?

A

Multiply the WBC by the percentage of neutrophils (the segs plus the bands) and divide by 100

ANC (cells/mm^3) = WBC x [(% segs + % bands)/100]

96
Q

How can neutrophils be labeled on a lab report?

A

Neutrophils can be labeled polymorphonuclear cells (PMNs or polys) or segmented neutrophils (segs) on a lab report

NAPLEX Review (45 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions