Ch. 11

Question 1

Define respiratory failure.

Answer 1

the inability of the respiratory system to maintain an adequate amount of (1) oxygen (O2) exchange between the alveoli and the pulmonary capillaries, or (2) carbon dioxide (CO2) removal out of the lungs, or (3) a combination of both.

Question 2

Identify the six major anatomic alterations of the lungs
and subsequent clinical scenarios that can lead to respiratory failure.

Answer 2

(1) atelectasis
(2) alveolar consolidation
(3) increased alveolar- capillary membrane thickness
(4) bronchospasm
(5) excessive bronchial secretions
(6) distal airway and alveolar weakening

Question 3

Evaluate the two major classifications of respiratory
failure.

Answer 3

(1) hypoxemic (type I) respiratory failure, or (2) hypercapnic (type II) respiratory failure, or (3) a combination of both.

Question 4

Describe hypoxemic respiratory failure (type I)
(oxygenation failure).

Answer 4

Hypoxemic respiratory failure (type I) is used to describe a patient whose primary problem is inadequate oxygenation. Patients with hypoxemic respiratory failure typically demon- strate hypoxemia—a low PaO2—and a normal, or low PaCO2 value.

Question 5

Explain respiratory disorders associated with hypoxemic
respiratory failure.

Answer 5

Question 6

Discuss the pathophysiologic mechanisms of hypoxemic
respiratory failure.

Answer 6

(1) alveolar hypoventilation,
Oxygenated blood
(2) pulmonary shunting, and
(3) ventilation-perfusion (V /Q ) mismatch.

Question 7

Describe hypercapnic respiratory failure (type II)
(ventilatory failure).

Answer 7

when the primary problem is alveolar hypoventilation. Patients
with hypercapnic respiratory failure demonstrate an increased
PaCO2 and, without supplemental oxygen, a decreased PaO2.

Question 8

Describe the pathophysiologic mechanisms of hypercapnic
respiratory failure.

Answer 8

1. Alveolar hypoventilation
2. Inc. dead space disease
3. V/Q ratio mismatch

Question 9

Explain respiratory disorders associated with hypercapnic
respiratory failure.

Answer 9

Question 10

Differentiate the types of ventilatory failure.

Answer 10

(1) acute ventilatory failure (high PaCO2 and low pH), or (2) chronic ventilatory failure (high PaCO2 and normal pH).

Question 11

Describe the major components of the mechanical
ventilation protocol.

Answer 11

Non invasive or invasive ventilation

Question 12

What is pulmonary shunting?

Answer 12

the portion of the cardiac output that moves from the right side to the left side of the heart without being exposed to alveolar oxygen (PAO2)

Question 13

What is alveolar hypoventilation?

Answer 13

an abnormal condition of the respiratory system that develops when the volume and distribution of alveolar ventilation is not adequate for the body’s metabolic needs. It is characterized by an increased PaCO2 level and, without supplemental oxygen, a decreased PaO2.

Question 14

What is V/Q mismatch?

Answer 14

Under normal conditions, the overall alveolar ventilation is
about 4 L/min and pulmonary capillary blood flow is about
5 L/min, making the average overall ratio of ventilation to
blood flow about 4 : 5 or 0.8.

Question 15

What is the formula for the VD/VT ratio?

Answer 15

Question 16

What is the formula for the A-a gradient?

Answer 16

PAO2 = FIO2 (PB − PH2O) − PaCO2 x 1.25

Question 17

What is the normal range for the A-a gradient?

Answer 17

7-15mmHg

Question 18

What is another name for Hypercapnic Respiratory Failure?

Answer 18

Ventilatory failure

Question 19

What is another name for Hypoxemic Respiratory Failure?

Answer 19

Oxygenation failure

Question 20

What are the common causes of alveolar hypoventilation?

Answer 20

central nervous system depressants, head trauma, chronic obstructive pulmonary disease, obesity, sleep apnea, and neuromuscular disorders (e.g., myasthenia gravis or Guillain-Barré syn- drome).

Question 21

What is the tx for alveolar hypoventilation?

Answer 21

Ventilate support

Question 22

What are absolute shunts?

Answer 22

(also called true shunt) are commonly classified under two major categories: anatomic shunt and capillary shunt.

Question 23

What is the normal anatomic shunt?

Answer 23

In the healthy lung, there is a normal anatomic shunt of about 3% of the cardiac output.

Question 24

What are capillary shunts?

Answer 24

caused by (1) alveolar collapse or atelectasis, (2) alveolar fluid accumulation, or (3) alveolar con- solidation or pneumonia

Question 25

What are relative shunts?

Answer 25

or a shunt- like effect is said to be present (Figure 10-1). Relative shunt are caused by an airway obstruction, an alveolar- capillary diffusion defect, or a combination of both.

Question 26

What is the normal A-a gradient for a pt on 100% O2?

Answer 26

25-65mmHg

Question 27

What is the critical value for the A-a gradient?

Answer 27

350 mmHg

Question 28

What are somethings that inc the A-a gradient?

Answer 28

High O2
(1) oxygen diffusion disorders (e.g., chronic interstitial lung diseases), (2) ventilation- perfusion ratio mismatching, (3) right-to-left intracardiac shunting (e.g., a patent ventricular septum), and (4) age.