quiz 8

Question 1

Sao2 90, 75, 50. what is Po2?

Answer 1

60, 40, 27

Question 2

can you use standard pulse ox in MRI?

Answer 2

no, need MRI pulse ox

Question 3

will endobronchial intubation be seen on pulse ox?

Answer 3

usually not noticed

Question 4

list of pulse ox limitations d/t no pulse or low perfusion?

Answer 4

Hypotension
Hypothermia
Hypovolemia = shock
Hypoperfusion = low cardiac output
Tourniquet
BP cuff inflation
Asystole, V.Fib.
Peripheral vasoconstriction = increased SVR

Question 5

Fetal hemoglobin and bilirubin ______ affect pulse oximetry

Answer 5

do not

Question 6

shows a SpO2 of 100%, this is an overestimation of the true oxygenation, co-oximeter used to distinguish between the two?

Answer 6

Carboxyhemoglobin

Question 7

When Fe+2(ferrous) in Hb is oxidized to Fe+3 (ferric) form and cannot transport O2? O2 sat is ~85% - Why?

Treatment?

Answer 7

Methemoglobin

absorbs equally at both wavelengths, 1:1

Methylene Blue or ascorbic acid

Question 8

What can cause Methemoglobin?

Answer 8

benzocaine (hurricane spray)**
nitrates
nitrites
nitroglycerine
nitroprusside
sulfonamides

Question 9

ETCO2 can reliably indicate ______ but not ______

Answer 9

esophageal intubation
not
Endobronchial intubation

Question 10

gold standard for tracheal intubation?

Answer 10

ETCO2

Question 11

Pulse oximetry Measures a difference between _______ absorption in diastole and ________ absorption during systole

Answer 11

background

peak

Question 12

infrared light what number?, ______ absorbs more of this light, corresponds to ______ saturation

Answer 12

940nm

oxyhemoglobin

100%

Question 13

red light what number? ________ absorbs more of this light, corresponds to ____ saturation

Answer 13

660nm

deoxyhemoglobin

50%

Question 14

Poor accuracy for pulse ox at SpO2 less than?

Answer 14

30%

Question 15

poor accuracy of pulse ox when Hgb less than?

Answer 15

3-4

Question 16

poor accuracy of pulse ox with venouse pulsations such as?

Answer 16

Right heart failure (cor pulmonale)
tricuspid regurgitation

seen in dependent (down) limb

Question 17

Normal end-tidal CO2 to arterial CO2 gradient (dCO2) is

what does this value represent?

Answer 17

2-5 mmHg

alveolar deadspace

Question 18

reasons for dCO2 (deadspace) ?

Answer 18

• Decreased PAP
• Upright posture
• Pulmonary emboli (PE): air, fat, thrombus, amniotic fluid
• COPD
• Mechanical obstruction of pulmonary artery
• Ventilated gas leaving normal pathway: cuff leak, tracheal disruption, bronchopleural fistula
• Decreased CO or decreased BP

Question 19

Causes of increased EtCO2

Answer 19

• Malignant hyperthermia
• Hypoventilation (most common)
• Bicarbonate
• Laparoscopy (CO2 inflation)
• Hyperthermia
• Improved blood flow to lungs after hypotension or resuscitation
• Tourniquet released
• Water in capnograph sensor
• Breathing circuit error: CO2 absorber exhausted, -rebreathing, inadequate fresh gas flow, faulty valves in circuit

Question 20

Causes of decreased EtCO2

Answer 20

Hyperventilation
Airway leak, leak around cuff
Decreased blood flow to lungs
Pulmonary embolism
Decreased cardiac output, arrhythmias
Incipient pulmonary edema
Hypothermia
Inadequate sample volume
Sample catheter misplaced