Calculations IV

Question 1

Acid-Base and arterial blood gases:

pH decreases as a solution becomes more ___________

Answer 1

acidic

Question 2

Acid-Base and arterial blood gases:

pH increases as a solution becomes more ___________

Answer 2

basic (alkaline)

Question 3

Human blood has a pH of __________________

Answer 3

7.4, slightly alkaline

Question 4

As a solution becomes more acidic (the concentration of protons increases), and the pH ____________

Answer 4

decreases

Question 5

As a solution becomes more basic (the concentration of protons decreases), and the pH _______________

Answer 5

increases

Question 6

Pure water is neutral having a pH of

Answer 6

7

Question 7

Stomach acid has a pH of ________

Answer 7

2, and is therefore acidic.

Question 8

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

The primary buffering system of the body is the ____________ system.

Answer 8

bicarbonate/carbonic acid

Question 9

The kidneys help to maintain a neutral pH by controlling bicarbonate (HCO3) reabsorption and elimination.

Answer 9

The lungs help maintain a neutral pH by controlling carbonic acid (which is directly proportional to the partial pressure of carbon dioxide or pCO2) retained or released from the body. Carbon dioxide acts as a buffer and an acid.

Question 10

(ABG) Arterial Blood Gases: what does each letter represent?

A/B/C/D/E

Answer 10

pH/pCO2/pO2/HCO3/O2 Sat

Question 11

(ABG) Arterial Blood Gases:

What is the reference range for pH?

Answer 11

7.35-7.45

Question 12

(ABG) Arterial Blood Gases:

What is the reference range for CO2?

Answer 12

35-45 mmHg

Question 13

(ABG) Arterial Blood Gases:

What is the reference range for O2?

Answer 13

80-100 mmHg

Question 14

(ABG) Arterial Blood Gases:

What is the reference range for HCO3?

Answer 14

22-26 mEq/L

Question 15

(ABG) Arterial Blood Gases:

What is the reference range for

Answer 15

> 95%

Question 16

Our lungs and our kidneys help regulate ___________

Answer 16

acid-base balance in the body

Question 17

The lungs can help us retain or blow off ________

Answer 17

CO2

• which is an acid in the pulmonary system

Question 18

Our kidneys help us retain or excrete _______

Answer 18

bicarbonate (HCO3)

• a basic component in the metabolic system

Question 19

When interpreting ABGs:

1) First step is too look at the pH and see if it is within range or if,

too low

too high

Answer 19

If the pH is low, then we know we have an acidosis

If the pH is high, then we know we have an alkalosis

Question 20

When interpreting ABGs:

2) Second step is too determine what other ABGs are abnormal:

If the CO2 is too high then we have a ____1______.

If the CO2 is too low then we have a _____2______.

remember CO2 is eliminated through the _____3______

Answer 20

1) acidosis (respiratory)

2) alkalosis (respiratory)

3) lungs

Question 21

When interpreting ABGs:

2) Second step is too determine what other ABGs are abnormal:

If the HCO3 is too high then we have a ______1______.

If the HCO3 is too low then we have a ______2_______.

remember HCO3 is eliminated through the _____3_____

Answer 21

1) alkalosis (metabolic)

2) acidosis (metabolic)

3) kidneys

Question 22

When interpreting ABGs:

3) Third step: Which of the abnormal values in step 2 matches with the pH in step 1?

Answer 22

ex. pH is decreased, CO2 is increased, and HCO3 is normal

pH indicated acidosis.

CO2 elevated also indicates acidosis.

so, patient has a respiratory acidosis.

Question 23

When interpreting ABGs:

4) Step 4: What if both CO2 and HCO3 are abnormal?

Answer 23

Usually only one of the values will match the pH, the other will go in the opposite direction from the pH. This is called compensation.

ex. pH is decreased, CO2 is decreased, and HCO3 is decreased

pH indicates acidosis.
CO2 indicates alkalosis.
HCO3 indicates acidosis.

This would be considered metabolic acidosis. with some degree of respiratory compensation.

Question 24

pH/pCO2/pO2/HCO3/O2 Sat

what are the reference ranges for each component in an arterial blood gas (ABGs):

Answer 24

pH = 7.35-7.45
pCO2 = 35-45 mmHg
pO2 = 80-100 mmHg
HCO3 = 22-26 mEq/L —————- for an arterial blood draw, if a venous blood draw values will differ.
O2 sat = > 95%

** remember we don’t use the pO2 or O2 saturation, when interpreting ABGs**

Question 25

when a patient is experiencing metabolic acidosis, it is common to calculate an ________________.

Answer 25

anion gap

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

Question 26

exs. of metabolic acidosis

a mnemonic to remember the causes of a gap acidosis is
CUTE DIMPLES =

Answer 26

DKA, toxicity,

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

Question 27

The anion gap is considered high if it is, __________________

Answer 27

> 12 mEq/L (meaning the patient has a gap acidosis)

Question 28

Buffer Systems and Ionization:

When the pKa = pH, this is the point which ____________

Answer 28

half the compound is protonated, and half is NOT protonated.

Question 29

Buffer Systems and Ionization:

Any time you are given a pKa, it refers to the ____________

Answer 29

acid form losing protons to the base form.

Question 30

Buffer Systems and Ionization:

If the pH > pKa, then ____

Answer 30

more of the acid is ionized, and more of the conjugate base is un-ionized.

Question 31

Buffer Systems and Ionization:

If the pH < pKa, then ______

Answer 31

more of the acid is un-ionized, and more of the conjugate base is ionized.

Question 32

Buffer Systems and Ionization:

If the pH = pKa, then ________

Answer 32

the ionized and un-ionized forms are equal.

Question 33

Percent ionization:

Answer 33

Is the percentage of the drug in the solution that has deprotonated.

Question 34

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

Answer 34

susceptible