Rspt 1340 Beachey Ch 12 Ventilation-Perfusion

Front 1

What is the major effect of a low VA/QC ratio?

Back 1

Hypoxemia

Front 2

What are the causes of general hypoventilation?

Back 2

Muscle paralysis, muscle weakness, and drug induced respiratory center depression

Front 3

What conditions are associated with Intrapulmonary shunting?

Back 3

Pneumonia, Pulmonary edema, Pneumothorax, and Bronchial occlusion

Front 4

What changes are consistent with hypoxemia due to hyperventilation?

Back 4

Reciprocal changes between PaCO2 and Pa02

Front 5

What techniques prevent alveolar collapse even during expiration?

Back 5

Peep and Cpap

Front 6

What conditions are associated with the dead space?

Back 6

Pulmonary embolism, Severe hypotension, Alveolar overdistension, and Auto-peep

Front 7

What are the major characteristics of increased alveolar dead space?

Back 7

Increased work of breathing and VE out of proportion with the PaCO2

Front 8

What is true of P(A - a)O2?

Back 8

-Increased P(A - a)O2 indicates increased physiological shunting.

-Normal P(A - a)O2 is approximately 7 to 14 mmHg during breathing of Room air.

-P(A - a)O2 is as high as 50 to 60 MMHg during the breathing of 100% oxygen.

-The variability of P(A - a)O2 with FIO2 limits its usefulness as a shot indicator when FIO2 is changed.

Front 9

What statements are true of PaO2/PA02?

Back 9

-PaO2/PA02 is more stable than

P(A-a)O2 when FIO2 changes.

-The lower normal limit of PaO2/PA02 is approximately 0.75.

Front 10

What statements are true of the Pa02/FIO2?

Back 10

- A normal changes approximately 380 to 475.

- Its usefulness as a shunt indicator is limited.

- The major problem with Pa02/FIO2 is that changes in PaCO2 affect it.

-Pa02/FIO2 is the least accurate indicator of shunt.

Front 11

What is the definition of absolute shunt?

Back 11

When ventilation gradually decreases to 0 with no change and blood flow.

Front 12

What is anticipated P(A - a)02 when 100% oxygen is breathed?

Back 12

50 mmhg

Front 13

What explains why the mere breathing of 100% oxygen increases the P(A-a)O2 ?

Back 13

Because of the unique way hemoglobin binds to 02 molecules.

Front 14

Increasing the FIO2 in patients with shunting will have what effect?

Back 14

It does little to improve arterial oxygenation.

Front 15

What is the hallmark of Intrapulmonary shunting?

Back 15

Refractory hypoxemia

Front 16

What equation is an indicator of the severity of a shunt?

Back 16

P(A-a)O2

Front 17

What is considered the best corrective treatment for intrapulmonary shunting?

Back 17

Restore ventilation to airless alveoli

Front 18

What clinical conditions associated with alveolar collapse may be adversely affected by peep/cpap?

Back 18

Pneumothorax

Front 19

What is the most common cause of hypoxemia?

Back 19

VA/QC mismatch

Front 20

Increasing the FIO2 in patients with VA/QC mismatch will have what effects?

Back 20

Raise your PA02

Front 21

What is the explanation for the production of hyperventilation and respiratory alkalosis associated with hypoxemia?

Back 21

Peripheral chemoreceptor stimulation

Front 22

What type of patients with severe flow limitation and VA/QC mismatch may be unable to increase their over all alveolar venilation enough to sustain a normal PaCO2?

Back 22

Advanced COPD

Front 23

The record of a patient on mechanical ventilation reveals the following information: VE equals 10 L/min, PaCO2 = 43 mmhg, PECO2 equal 17 MMHG, PaO2=70 mmhg. Can ventillation be considered efficient for this patient?

Back 23

PaO2-PeCO2÷PaCO2

43-17÷43=.6 or 60%

No, because the dead space value is more than 40%.

Front 24

Assuming that cardiovascular function is constant the blank is the most reliable shunt indicator.

Back 24

Pa02/PAO2

Front 25

A physician is trying to determine the best index of oxygenation for a patient undergoing mechanical ventilation who has required frequent changes in FIO2. What available in indices of oxygenation should be recommended for this patient?

Back 25

PaO2/PAO2

Front 26

Which level of calculated shunt fraction is associated with the least significant clinical effect?

Back 26

10% or less

Front 27

What are some examples of an anatomic shunt that physically bypasses alveoli?

Back 27

Ventricular septal defect And bronchial veneous admixture

Front 28

What are some examples of an intrapulmonary shunt which flows through capillaries of and unventilated alveoli?

Back 28

Atelectasis, pulmonary edema, pneumonia, bronchial occlusion, ards, airway mucus plug, and pneumothorax

Front 29

A young previously healthy drug overdose victim in the ER presents with the following ABG's while breathing Room air: PH 7.22 , P02 59 mmhg, PCO2 63 mmhg, barometric pressure 760 mmhg. What is the mechanism causing this person's hypoxemia? over all hyperventilation, VQ mismatch, or absolute shunt? Calculate PA02. Is there an oxygen transfer alveolar gas to capillary blood problem?

Back 29

Overall hyperventilation, PAO2 74.13 mmhg, no there is not an oxygen transfer problem.

Front 30

A patient diagnosed with COPD presents with the following ABG's while breathing Room air: PH 7.45 , P02 60 mmhg, PCO2 33 mmhg, barometric pressure 730 mmhg. What is the mechanism causing this person's hypoxemia? over all hyperventilation, VQ mismatch, or absolute shunt? Can any of these mechanisms be immediately ruled out? This patient was given oxygen via nasal cannula at 2 L/min. Their resulting Pa02 was 90mmhg. What is the predomincant hypoxemia mechanism?

Back 30

V/Q mismatch, A shunt responds poorly to oxygen therapy.