Cardio/Pulm common laboratory tests

Question 1

What is purpose of arterial blood gases test?

Answer 1

Evaluate:

• acid-base status (pH)
• ventilation (PaCO2)
• oxygenation of arterial blood (PaO2)

Question 2

What does the PaO2 and SaO2 tell us?

Answer 2

Partial pressure of oxygen in arterial blood (PaO2) and percent oxygen saturation of hemoglobin (SaO2) explain how well lungs are functioning to oxygenate the blood

Question 3

What does the PaCO2 (partial pressure of carbon dioxide) of arterial blood tell us?

Answer 3

tells us how well the lungs are removing CO2 from the blood

Question 4

What do changes in the PaCO2 cause?

Answer 4

changes in the blood pH

Question 5

What occurs if there is an imbalance in the blood pH?

Answer 5

imbalance in either direction affects the nervous system and can cause convulsions or coma

Question 6

What is the function of bicarbonate (HCO3-)?

Answer 6

• part of the chemical buffering system that keeps blood from becoming too acidic or basic
• often part of the ABG test

Question 7

What is collected in an ABG?

Answer 7

1) pH
2) PaCO2
3) PaO2
4) HCO3-
5) SaO2

Question 8

What is the average range of adult blood pH?

Answer 8

7.4 (7.35-7.45)

Question 9

What is the average range of adult blood PaCO2?

Answer 9

40 mmHg at sea level breathing ambient air

35-45 mmHg

Question 10

What is the average range of adult blood PaO2?

Answer 10

97 mmHg at sea level breathing ambient air

80-100 mmHg

Question 11

What is the average range of adult blood HCO3-?

Answer 11

24 mEq/L (22-26 mEq/L) milliequivilants of solute per litre of solvent

Question 12

What is the average range of adult blood SaO2?

Answer 12

95-98%

Question 13

What is acidemia?

Answer 13

elevated acidity of blood, pH is less than 7.35

Question 14

What is alkalemia?

Answer 14

decreased acidity of blood, pH is greater than 7.45

Question 15

What is hypoxemia?

Answer 15

low level of O2 in arterial blood (PaO2 <80 mmHg)

Question 16

What is hypoxia?

Answer 16

low level of O2 in the tissue despite adequate perfusion of the tissue

Question 17

What is respiratory acidosis?

Answer 17

decreased ventilation (hypoventilation) increases [CO2] in blood –> decreases blood pH –> making it more acidic

Question 18

What is respiratory alkalosis?

Answer 18

alveolar hyperventilation decreases PaCO2

-reflexes causes a decrease in ventilation rate

Question 19

What does a cholesterol test measure?

Answer 19

aka lipid panel

• amount of cholesterol and triglycerides in the blood
• determines risk of atherosclerosis
• Consists of four parts: total cholesterol, HDL, LDL, and tryglycerides

Question 20

What does a Complete Blood Count measure?

Answer 20

RBC count
total WBC count
white blood cell differential
platelets
hemoglobin
hematocrit

Question 21

What is the hematocrit reading?

Answer 21

percentage of RBC in total blood volume

• low may indicate anemia, blood loss, and vitamin or mineral deficiencies
• high may indicate dehydration, polycythemia vera (condition that causes over production of RBCs)

Question 22

What is a PTT Partial thromboplastin and prothrombin Time (PT) test?

Answer 22

• measures how quickly blood clots
• used to monitor oral anticoagulant therapy or screen for bleeding disorders
• examines clotting factors of the intrinsic pathway with the exception of platelets
• PTT is more sensitive than PT