title: The effects of anesthesia and muscle paralysis on the respiratory system.
abstract: BACKGROUND
  Oxygenation is impaired in almost all subjects during anesthesia, and hypoxemia for shorter or longer periods is a common finding. Moreover, postoperative lung complications occur in 3-10% after elective abdominal surgery and more in emergency operations.
  
  
  CONCLUSIONS
  Rapid collapse of alveoli on induction of anesthesia and more widespread closure of airways seem to explain the oxygenation impairment and may also contribute to postoperative pulmonary infection. Causative mechanisms to atelectasis and airway closure seem to be loss of respiratory muscle tone and gas resorption.
  
  
  CONCLUSIONS
  Avoiding high inspired oxygen fractions during both induction and maintenance of anesthesia prevents or reduces atelectasis, while intermittent "vital capacity" maneuvers recruit atelectatic lung regions.
authors.affiliation: Clinical Physiology, Department of Medical Sciences, University Hospital, 75185 Uppsala, Sweden. goran.hedenstierna@medsci.uu.se
authors.forename: Göran
authors.initials: G
authors.lastname: Hedenstierna
authors.forename: Lennart
authors.initials: L
authors.lastname: Edmark
mesh_terms: D000758:Anesthesia / Q000009:adverse effects*; D006801:Humans; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects*; D011175:Positive-Pressure Respiration; D001261:Pulmonary Atelectasis / Q000209:etiology / Q000517:prevention & control; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012128:Respiratory Distress Syndrome / Q000209:etiology*; D012133:Respiratory Paralysis / Q000209:etiology*; D012137:Respiratory System