What is the pathophysiology of postoperative atelectasis?

Updated: Oct 22, 2020
  • Author: Tarun Madappa, MD, MPH; Chief Editor: Nader Kamangar, MD, FACP, FCCP, FCCM  more...
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Answer

Atelectasis is a common pulmonary complication in patients following thoracic and upper abdominal procedures. General anesthesia and surgical manipulation lead to atelectasis by causing diaphragmatic dysfunction and diminished surfactant activity. The atelectasis is typically basilar and segmental in distribution. After induction of anesthesia, atelectasis increases from 1 to 11% of total lung volume. End-expiratory lung volume is also found to be decreased.

In 2009 study, a recruitment maneuver plus positive end-expiratory pressure (PEEP) reduced atelectasis to 3 ±4%, increased end-expiratory lung volume, and increased the PaO2/FiO2 ratio from 266 ±70 mm Hg to 412 ±99 mm Hg. It was found that the PEEP alone did not reduce the amount of atelectasis or improve oxygenation, but a recruitment maneuver followed by PEEP reduced atelectasis and improved oxygenation. [5]


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