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Reference: JAMA 2014 Aug 20;312(7):712 (level 2 [mid-level] evidence)
Pulse oximetry is routinely used in the assessment and monitoring of children with bronchiolitis. It is a safe and convenient way of measuring oxygenation status, and may detect hypoxemia before it becomes clinically apparent. The American Academy of Pediatrics (AAP) guideline currently recommends that supplemental oxygen should be used in children with bronchiolitis with oxygen saturation persistently ≤ 89% on pulse oximetry (Pediatrics 2006 Oct;118(4):1774 full-text). However, the role of oximetry as part of the decision on whether to admit children to hospital is unclear. A recent randomized trial of 213 infants aged 1-12 months with mild-to-moderate bronchiolitis evaluated the effect of oximetry readings on hospitalization rates.
All infants had oxygen saturation ≥ 88% (mean 97% in each group) at baseline and were randomized to oximetry measurements that were artificially elevated by 3% above true values vs. true oximetry values. The primary outcome was hospitalization within 72 hours or hospital care for ≥ 6 hours due to concerns about respiratory distress. The primary outcome rate was 25% with artificially elevated oximetry display vs. 41% with true oximetry display (p = 0.005). There were no significant between-group differences in the amount of supplemental oxygen administered in the emergency department, or in the length of hospital stay. As well, there was no significant difference in the rate of unscheduled medical visits for bronchiolitis.
Pulse oximetry is one of several different factors used in evaluating the need to admit an infant with bronchiolitis to the hospital, and clinical findings such as respiratory distress or feeding difficulties may indicate a need for hospital admission irrespective of oxygen saturation values. The findings from this trial are consistent with those of a previous observational study that found that oxygen saturation levels were a significant predictor of hospital admission after emergency department evaluation for moderate-to-severe bronchiolitis (Pediatr Emerg Care 2012 Feb;28(2):99). However, the ability to interpret these new results is limited by the fact that most infants in the study had near-normal oxygen saturation at baseline (mean oxygen saturation was 97%, and only 13% overall had oxygen saturation < 94%). Nonetheless, these findings suggest that there may be an overreliance on pulse oximetry in deciding whether to admit infants with mild-to-moderate bronchiolitis to the hospital. These data highlight the need to avoid weighing a single finding in isolation, rather than viewing it as one piece of a larger clinical picture.
For more information see the Bronchiolitis topic in DynaMed.