Physiologic and Pathophysiologic Consequences of Mechanical Ventilation article

Question 1

Can mechanical ventilation be performed using either positive pressure or negative pressure?

Answer 1

• yes, both can be used

positive pressure ventilation is the primary type used today

Question 2

What are the two major consequences of positive pressure ventilation?

Answer 2

• barotrauma

- ventilator-associated lung injury

Question 3

Besides barotrauma and ventilator-associated lung injury, what are some other negative pulmonary effects from positive pressure ventilation? (7 things)

Answer 3

• intrinsic positive end expiratory pressure (auto-PEEP)
• heterogeneous ventilation
• increased physiologic dead space
• decreased physiologic shunting
• diaphragmatic muscle atrophy
• respiratory muscle weakness
• diminished mucociliary motility.

Question 4

What is meant by auto-PEEP?

Answer 4

• it is when there is positive airway pressure at the end of expiration due to incomplete exhalation.

(It exacerbates the hemodynamic effects of positive pressure ventilation, increases the risk of pulmonary barotrauma, and makes it more difficult for the patient to trigger a ventilator-assisted breath)

Question 5

Positive pressure ventilation can cause non-pulmonary effects throughout the body. Name a few. (there are a total of eight)

Answer 5

• gastrointestinal stress ulceration
• decreased splanchnic perfusion
• gastrointestinal hypomotility
• fluid retention
• acute renal failure
• increased intracranial pressure
• weakness, inflammation
• disordered sleep