1. Oxygen saturation decreases acutely when opioids are given during anaesthesia 
G.B. Drummond, B. Lafferty 
British Journal of Anaesthesia 
Volume 104, Issue 5, Pages (May 2010)
DOI: /bja/aeq076
Copyright © 2010 The Author(s) Terms and Conditions

2. Fig 1
Changes in oxygen saturation associated with administration of fentanyl in a representative patient. Note the absence of changes in ventilation. This patient was undergoing laparoscopy.
British Journal of Anaesthesia  , DOI: ( /bja/aeq076)
Copyright © 2010 The Author(s) Terms and Conditions