CARDIOPULMONARY CONSIDERATIONS

Question 1

ISCHEMIC HYPOXIA

Answer 1

• decreased/absent blood flow
• heart failure (systemic hypoxia)
• shock (peripheral hypoxia)
• thrombosis (hypoxia in single organ)

Question 2

HISOTOXIC HYPOXIA

Answer 2

• failure of cells to use O2 due to cell poisoning

Question 3

HYPOXIC HYPOXIA

Answer 3

• low arterial PO2

TYPICAL CAUSES

• high altitude; alveolar hypoventilation
• decreased lung diffusion capacity
• abnormal Vent-Perf ratios

Question 4

ANEMIC HYPOXIA

Answer 4

• decreased total amount of O2 bound to hemoglobin

TYPICAL CAUSES

• blood loos
• CO poisoning
• anemia

Question 5

EXPIRATORY RESERVE VOLUME

Answer 5

• additional volume of air that can be exhaled forcefully AFTER a tidal exhalation
• approx 1 - 1.5 L

ERV = EC - VT

Question 6

TIDAL VOLUME

Answer 6

• volume of air during single normal breath under resting conditions
• approx 500 ml

Question 7

TOTAL LUNG CAPACITY

Answer 7

• amount of air in lungs after a max (forced) inhalation

- TLC = FVC + RV

Question 8

FUNCTIONAL RESIDUAL CAPACITY

Answer 8

• FRC
• amount of air left in lungs after a normal (unforced) exhalation

FRC = ERV + RV

Question 9

RESIDUAL VOLUME

Answer 9

• RV
• volume of air left in lungs after maximum exhale
• ~25% VC females; ~35% VC in males
• increases w/ age

Question 10

FORCED EXPIRATORY VOLUME

Answer 10

• FEV

- pulm fxn test that measures % of air expelled in set amount of time (i.e. FEV1) = FEV in 1 second

Question 11

VITAL CAPACITY

Answer 11

• VC
• max volume of air exhaled after maximum inhalation
• VC = VT + ERV + IRV

Question 12

INSPIRATORY CAPACITY

Answer 12

• IC
• max amount of air that can be inhaled after a tidal exhalation
• IC = VT + IRV

Question 13

INSPIRATORY RESERVE VOLUME

Answer 13

• IRV
• additional volume of air that can be inhaled after a tidal inhale
• approx volume = 2.5 - 3.5 L

Question 14

LUB

Answer 14

• S1
• closure of AV valves
• beginning of ventricular systole

Question 15

DUB

Answer 15

• S2
• closure of SL valves
• beginning of ventricular diastole

Question 16

P-wave

Answer 16

• atrial depolarization
• duration: 80 ms
• normal: electrical signal spread from SA to AV node

Question 17

P-R Segment

Answer 17

• connects P wave to QRS complex
• DURATION: 50 - 120 ms
• electrical vector from AV node to bundle of His to bundle branches to Purkinje fibers
• shows flat on ECG reading

Question 18

P-R Interval

Answer 18

• measured P-wave to beginning of Q-wave
• reflects time taked for AP to travel from SA node to AV node and enter ventricles
• good estimate of AV node fxn
• duration: 120 to 200 ms

Question 19

QRS Complex

Answer 19

• ventricular depolarization & atrial repolarization

- duration: 80 to 120 ms

Question 20

ST Segment

Answer 20

• starts at end of S-wave and ends at beginning of T-wave
• isoelectric
• period where ventricles are fully depolarized
• duration: 80 - 120 ms

Question 21

T-Wave

Answer 21

• ventricular repolarization

- duration: 160 ms

Question 22

ABSOLUTE REFRACTORY PERIOD

Answer 22

• interval from beginning of QRS complex to apex of T-wave

Question 23

RR Interval

Answer 23

• interval between to R spikes, represents 1 cardiac cycle
• used to calculate HR
• duration: 0.6 to 1.2 sec