Chapter 09: Ventilatory Assistance

Chapter 09: Ventilatory Assistance

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. A patient has coronary artery bypass graft surgery and is transported to the surgical intensive care unit at noon and is placed on mechanical ventilation. Interpret the initial arterial blood gas levels

pH: 7.31

PaCO₂: 48 mm Hg

Bicarbonate: 22 mEq/L

PaO₂: 115 mm Hg

O₂ saturation: 99%

a.	Normal arterial blood gas levels with a high oxygen level
b.	Partly compensated respiratory acidosis; normal oxygen
c.	Uncompensated metabolic acidosis with high oxygen levels
d.	Uncompensated respiratory acidosis; hyperoxygenated

 

 

ANS:  D

The high PaO₂ level reflects hyperoxygenation; the PaCO₂ and pH levels show respiratory acidosis. The respiratory acidosis is uncompensated as indicated by a pH of 7.31 (acidosis) and a normal bicarbonate level. No metabolic compensation has occurred.

 

DIF:    Cognitive Level: Analyze/Analysis                                   REF:   Box 9-3 | Table 9-3

OBJ:   Describe methods for assessing the respiratory system, including physical assessment, interpretation of arterial blood gases, and noninvasive techniques.

TOP:   Nursing Process Step: Assessment

MSC:  NCLEX Client Needs Category: Physiological Integrity

 

2. The provider orders the following mechanical ventilation settings for a patient who weighs 75 kg. The patient’s spontaneous respiratory rate is 22 breaths/min. Which arterial blood gas abnormality may occur if the patient continues to be tachypneic at these ventilator settings?

Settings:

Tidal volume: 600 mL (8 mL per kg)

FiO₂: 0.5

Respiratory rate: 14 breaths/min

Mode assist/control

Positive end-expiratory pressure: 10 cm H₂O

a.	Metabolic acidosis
b.	Metabolic alkalosis
c.	Respiratory acidosis
d.	Respiratory alkalosis

 

 

ANS:  D

Assist/control ventilation may result in respiratory alkalosis, especially when the

patient is breathing at a higher rate that the ventilator rate. Each time the patient initiates a spontaneous breath—in this case 22 times per minute—the ventilator will deliver 600 mL of volume.

 

DIF:    Cognitive Level: Analyze/Analysis                                   REF:   p. 186

OBJ:   Relate complications associated with mechanical ventilation.

TOP:   Nursing Process Step: Evaluation

MSC:  NCLEX Client Needs Category: Physiological Integrity

 

3. A patient’s ventilator settings are adjusted to treat hypoxemia. The fraction of inspired oxygen is increased from 0.6 to 0.7, and the positive end-expiratory pressure is increased from 10 to 15 cm H₂O. Shortly after these adjustments, the nurse notes that the patient’s blood pressure drops from 120/76 mm Hg to 90/60 mm Hg. What is the most likely cause of this decrease in blood pressure?

a.	Decrease in cardiac output
b.	Hypovolemia
c.	Increase in venous return
d.	Oxygen toxicity

 

 

ANS:  A

Positive end-expiratory pressure increases intrathoracic pressure and may result in decreased venous return. Cardiac output decreases as a result, and is reflected in the lower blood pressure. It is essential to assess the patient to identify optimal positive end-expiratory pressure—the highest amount that can be applied without compromising cardiac output. Although hypovolemia can result in a decrease in blood pressure, there is no indication that this patient has hypovolemia. As noted, higher levels of positive end-expiratory pressure may cause a decrease, not an increase, in venous return. Oxygen toxicity can occur in this case secondary to the high levels of oxygen needed to maintain gas exchange; however, oxygen toxicity is manifested in damage to the alveoli.

 

DIF:    Cognitive Level: Analyze/Analysis                                   REF:   p. 184 | p. 196

OBJ:   Relate complications associated with mechanical ventilation.

TOP:   Nursing Process Step: Evaluation

MSC:  NCLEX Client Needs Category: Physiological Integrity

 

4. The nurse is caring for a patient with an endotracheal tube. The nurse understands that endotracheal suctioning is needed to facilitate removal of secretions and that the procedure

a.	decreases intracranial pressure.
b.	depresses the cough reflex.
c.	is done as indicated by patient assessment.
d.	is more effective if preceded by saline instillation.

 

 

ANS:  C

Suctioning is performed as indicated by patient assessment. Suctioning is associated with increases in intracranial pressure; therefore, it is important to hyperoxygenate the patient before suctioning to reduce this complication. Suctioning can stimulate the cough reflex rather than depress this reflex. Saline instillation is associated with negative physiological outcomes and is not recommended as part of the suctioning procedure; it does not loosen secretions, which is a common misperception.

 

DIF:    Cognitive Level: Understand/Comprehension                    REF:   p. 180

OBJ:   Discuss methods for maintaining an open airway.

TOP:   Nursing Process Step: Implementation

MSC:  NCLEX Client Needs Category: Physiological Integrity