Perioperative respiratory failure is usually caused by atelectasis (collapse of lung tissue with loss of volume). (See also Overview of Mechanical Ventilation.)
Effective means of preventing or treating atelectasis include
Incentive spirometry
Ensuring adequate analgesia for chest and abdominal incisions
Upright positioning
Early mobilization
Atelectasis caused by abdominal distention should be alleviated according to the cause (eg, nasogastric suction for excessive intraluminal air, paracentesis to evacuate tense ascites).
Hypoperfusion, regardless of cause, may result in respiratory failure through inadequate delivery of oxygen to respiratory muscles coupled with excess respiratory muscle load (eg, acidosis, sepsis). Mechanical ventilation is useful for diverting blood flow from overworked respiratory muscles to critical organs such as the brain, kidney, and gut.
