Chapter 4; Establishing the Need for Mechanical Ventilation

Chapter 4; Establishing the Need for Mechanical Ventilation

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. Respiratory failure due to inadequate ventilation is known as which of the following?

a.	Hypoxemic
b.	Hypercapnic
c.	Compensated
d.	Chronic

 

 

ANS:   B

Inadequate ventilation decreases the amount of carbon dioxide excreted by the lungs. This causes a buildup of carbon dioxide in the blood, which is hypercapnia.

 

DIF:    1                      REF:    pgs. 49-51

 

2. The underlying physiological process leading to pure hypercapnic respiratory failure is which of the following?

a.	Ventilation/perfusion mismatch
b.	Intrapulmonary shunting
c.	Diffusion impairment
d.	Alveolar hypoventilation

 

 

ANS:   D

When a person cannot achieve adequate ventilation to maintain a normal partial pressure of carbon dioxide in the arteries (P_aCO₂), it is known as acute hypercapnic respiratory failure. Ventilation/perfusion (V/Q) mismatch, intrapulmonary shunting, and diffusion impairment lead to hypoxemic respiratory failure.

 

DIF:    1                      REF:    pgs. 49-51

 

3. A patient with an opiate drug overdose is unconscious and has the following arterial blood gas results on room air: pH 7.20; partial pressure of carbon dioxide (P_aCO₂) 88 mm Hg; partial pressure of oxygen (PaO₂) 42 mm Hg; bicarbonate (HCO₃^–) 25 mEq/L. Which of the following best describes this patient’s condition?

a.	Chronic hypoxemic respiratory failure
b.	Chronic hypercapnic respiratory failure
c.	Acute hypoxemic respiratory failure
d.	Acute hypercapnic respiratory failure

 

 

ANS:   D

A drug overdose will affect the patient’s central nervous system, knocking out the patient’s respiratory center. This will cause an increase in the partial pressure of carbon dioxide in the arteries (P_aCO₂). The alveolar hypoventilation is causing the low partial pressure of oxygen (P_aO₂). If this was a chronic hypercapnic respiratory failure the patient’s bicarbonate level would be elevated above the normal level.

 

DIF:    2                      REF:    pg. 50

 

4. Acute hypercapnic respiratory failure may be caused by which of the following?

a.	Decrease fractional inspired oxygen (FIO2)
b.	Pulmonary shunt
c.	Respiratory muscle fatigue
d.	Perfusion/diffusion impairment

 

 

ANS:   C

A decreased fractional inspired oxygen (FIO₂), pulmonary shunt, and perfusion/diffusion impairment will lead to acute hypoxemic respiratory failure. Respiratory muscle fatigue would decrease a patient’s ability to “move air” and would cause acute hypercapnic respiratory failure.

 

DIF:    1                      REF:    pg. 50

 

5. Hypercapnic respiratory failure due to increased work of breathing will be caused by which of the following?

a.	Drug overdose
b.	Myasthenia gravis
c.	Asthma exacerbation
d.	Pulmonary embolism

 

 

ANS:   C

An asthma exacerbation is characterized by bronchoconstriction due to bronchospasm, edema, and inflammation of the airways. This increases the amount of work a patient must do to overcome the increase in airway resistance, thereby increasing the patient’s work of breathing. A drug overdose causes hypercapnic respiratory failure, but because of a reduced drive to breathe. Myasthenia gravis is a neuromuscular disease that may paralyze the ventilatory muscles, causing a patient to not be able to move air. A pulmonary embolism would increase dead space by blocking off perfusion to a part of the lung. This would cause acute hypoxemic respiratory failure.

 

DIF:    1          REF:    pg. 50; Box 4-2