Bronchiolitis is a common presentation to paediatric emergency departments. In the absence of any effective treatments, most of the care focuses on supportive measures e.g. oxygen or feeding supplementation.
There is no clear cut-off for the requirement for supplemental oxygen, but this generally varies between 90 – 95% saturations. These cut-offs are often used to decide about admitting to hospital, but they are not predictive of the progression of the illness.
This randomised, double-blind, parallel-group trial aims to investigate the role of pulse oximetry in making decisions around hospital admissions. It essentially tries to determine whether as doctors, we over-rely on these measurements.
Schuh S, Freedman S, Coates A, Allen U, Parkin PC, Stephens D, Ungar W, DaSilva Z, Willan AR. Effect of oximetry on hospitalization in bronchiolitis: a randomized clinical trial. JAMA. 2014 Aug 20;312(7):712-8. doi: 10.1001/jama.2014.8637.
Who were the participants?
They were infants presenting with bronchiolitis to a tertiary paediatric emergency department over a five-year period. They had to have saturations of 88% or higher to be included.
Those with cardiopulmonary, neuromuscular, haematologic, or congenital airway anomalies were excluded. They also excluded those with severe respiratory distress.
There were 108 infants in the control group, and 105 infants in the intervention group.
What was the intervention?
Recruited infants were randomised to either the true saturation group or the altered saturation group.
Those in the altered saturation group had their saturations displayed three points higher than the true reading (i.e. if the true reading was 89% the sats monitor displayed 92%).
Doctors in the department knew that 50% of the infants would have their saturations altered in some way, but they didn’t know how much or in which direction.
What were the outcomes?
The primary outcome was admission to the hospital within 72 hours – this included either admission to the ward or active care for respiratory symptoms for at least six hours. Active care was: oxygen, IV fluids, or bronchodilators.
Secondary outcomes included: supplemental oxygen in ED, the timing of agreement for discharge home, length of stay, and representations within 72 hours.
What were the hospitalisation rates?
In the true saturations group, 41% were admitted. In the altered saturations group, only 25% were admitted (p=0.005)
There were no differences in the secondary outcomes (p=0.16).
What does this all mean for us?
By falsely elevating the oxygen satss by just three points, there was a significant reduction in hospital admission rates for bronchiolitis in infants.
Oxygen saturations are just one of the factors we should take into account when deciding on the need for admission in bronchiolitis. We must be careful not to over-depend on arbitrary cut-offs.