An American Academy of Pediatrics clinical practice guideline on the diagnosis and management of bronchiolitis was published recently in Pediatrics .1 This important guideline was evidence based and intended to help guide practitioners in the management of this commonly encountered and potentially serious condition. Recommendation 7a in the guideline includes the following statement: “If the Spo2 [pulse oxygen saturation] does persistently fall below 90%, adequate supplemental oxygen should be used to maintain Spo2 at or above 90%. Oxygen may be discontinued if Spo2 is at or above 90%… .”1 The authors state in … Address correspondence to Joel L. Bass, MD, Department of Pediatrics, Newton-Wellesley Hospital, 2014 Washington St, Boston, MA 02462. E-mail: jbass{at}partners.org