Deck 16: Extrapulmonary Effects of Mechanical Ventilation

Question 1

Which of the following can increase the physiological dead space in apneic patients receiving volume control ventilation?

A) I:E ratio >1:1
B) A slow flow rate
C) Adding an inflation hold
D) Inspiratory time <0.5 second

Answer 1

D
In an apneic patient receiving volume control ventilation,an inspiratory time that is too short (i.e.,<0.5 second)may result in an increase in physiological dead space.Large I:E ratios and addition of an inflation hold increase the mean airway pressure.A slow flow rate can inverse the I:E ratio and also cause an increase in mean airway pressure.

Question 2

Normovolemic patients experience decreases in cardiac output above what level of PEEP?

A) 5 cm H₂O
B) 8 cm H₂O
C) 12 cm H₂O
D) 15 cm H₂O

Answer 2

D
Decreases in cardiac output can occur in normovolemic patients with levels of PEEP >15 cm H₂O.

Question 3

Calculate the cerebral perfusion pressure when the mean arterial blood pressure is 120 mm Hg and the ICP is 14 mm Hg.

A) 134 mm Hg
B) 106 mm Hg
C) 120/14 mm Hg
D) 134/106 mm Hg

Answer 3

B
MABP - ICP = CPP

Question 4

Malnutrition during mechanical ventilation can cause which of the following?

A) Increased oxygen consumption
B) Increased carbon dioxide production
C) Increased work of breathing
D) Increased spontaneous ventilation

Question 5

High tidal volumes and/or high levels of PEEP can cause which of the following?

A) Improvement in pulmonary blood flow
B) Increased right ventricular afterload
C) Interventricular septum shifts to the right
D) Increased myocardial perfusion

Question 6

During spontaneous breathing,the fall in intrapleural pressure that draws air into the lungs during inspiration also draws blood into the major thoracic vessels.This phenomenon increases which of the following?

A) Systemic vascular resistance
B) Right ventricular afterload
C) Right ventricular preload
D) Pulmonary capillary resistance

Question 7

The mode that causes the greatest reduction in cardiac output during ventilation is which of the following?

A) CPAP
B) IMV
C) IMV with PEEP
D) VC-CMV with PEEP

Question 8

Positive pressure ventilation increases splanchnic resistance,decreases splanchnic venous outflow,and may contribute to gastric mucosal ischemia,which can contribute to which of the following?

A) Liver metastases
B) Gastric mucosal ischemia
C) Gastric ulcers
D) Increased portal blood flow

Question 9

Which of the following is the most likely cause of uneven ventilation?

A) Low set tidal volumes
B) High inspiratory flow rates
C) High mean airway pressures
D) Elevated peak inspiratory pressures

Question 10

The harmful cardiovascular effects of PPV are influenced most by which of the following pressures?

A) Peak inspiratory pressure
B) Mean airway pressure
C) Positive end-expiratory pressure
D) Transpulmonary pressure

Question 11

An otherwise healthy 19-year-old male is currently intubated and being mechanically ventilated after a motorcycle accident in which he sustained a closed head injury and multiple rib fractures.Before the patient is taken to the operating room for cranial surgery,the respiratory therapist notices that he has jugular vein distention.The most likely cause of this problem is which of the following?

A) Increased cardiac output
B) Decreased ventricular preload
C) Increased intracranial pressure
D) Decreased systemic vascular resistance

Question 12

Which of the following condition must exist to cause the interventricular septum to move to the left during positive pressure ventilation?

A) Volume overload
B) Cardiac tamponade
C) Mean airway pressure >15 cm H₂O
D) Decreased coronary artery perfusion

Question 13

Positive pressure ventilation has which of the following effects on the kidneys?

A) Increases blood flow to the kidneys
B) Redistributes blood flow in the kidneys
C) Decreases sodium reabsorption in the kidneys
D) Increases urinary output

Question 14

Urinary output is severely reduced when the renal arterial pressure decreases below what level?

A) 75 mm Hg
B) 85 mm Hg
C) 95 mm Hg
D) 105 mm Hg

Question 15

Which of the following patient conditions is least likely to experience hemodynamic changes with high alveolar pressures during mechanical ventilation?

A) ARDS
B) Emphysema
C) Kyphoscoliosis
D) Third-degree chest wall burns

Question 16

Mechanical ventilation has an effect on the hormone _____________,which causes a decrease in urinary output.

A) cortisol
B) arginine vasopressin
C) parathyroid hormone
D) thyroid-stimulating hormone

Question 17

Which of the following ventilator parameters would result in the highest mean airway pressure?

A) PIP = 30 cm H₂O; PEEP = 10 cm H₂O; TI = 0.5 sec; TCT = 5 sec
B) PIP = 50 cm H₂O; PEEP = 10 cm H₂O; TI = 0.5 sec; TCT = 5 sec
C) PIP = 30 cm H₂O; PEEP = 15 cm H₂O; TI = 0.5 sec; TCT = 5 sec
D) PIP = 50 cm H₂O; PEEP = 10 cm H₂O; TI = 0.5 sec; TCT = 5 sec..