COMMENTARY

Bronchiolitis After the ED: Should We Worry About O2 Saturation?

William T. Basco, Jr, MD, MS

Disclosures

April 25, 2016

Effect of Oxygen Desaturations on Subsequent Medical Visits in Infants Discharged From the Emergency Department With Bronchiolitis

Principi T, Coates AL, Parkin PC, Stephens D, DaSilva Z, Schuh S
JAMA Pediatr. 2016 Feb 29. [Epub ahead of print]

Study Summary

Since the widespread adoption of pulse oximetry in patient assessment, the frequency of bronchiolitis admissions has more than doubled. Recent evidence[1] suggests that pulse oxygen saturation (SpO2) levels are important drivers of the decision to admit a patient to the hospital from the emergency department (ED) and may unduly influence clinical decision-making.

This aim of this study was to evaluate oxygen desaturation events after discharge from the ED among children with bronchiolitis. The investigators were particularly interested in identifying whether an infant's SpO2 level in the first 72 hours after ED discharge was associated with increased use of healthcare. The sample comprised infants with bronchiolitis, aged 6 weeks to 12 months, excluding children with chronic medical conditions.

Children with a diagnosis of bronchiolitis were discharged from the ED with a pulse oximeter that monitored but did not display SpO2 values or issue alarms. Therefore, parents were unaware of the infant's SpO2 level. The oximeter probe issued an alarm only if it became dislodged from the infant, and parents were instructed on how to replace it. The parents also completed a diary of sleep and other activities. After the pulse oximeters were returned, study nurses interviewed the parents to obtain information on medical care received by their children during the 72-hour monitoring period.

Desaturation was defined as an SpO2 level < 90% that lasted for at least 1 minute. An "unscheduled medical visit" was any unplanned visit prompted by concerns about the child's respiratory status. "Major desaturation" was defined as at least three desaturation events or an SpO2 level < 90% for at least 10% of the time.

Study Findings

Data from 118 of the 139 enrolled children (mean age, 4.5 months) were available for analysis. Almost two thirds (63.6%) of the children experienced a desaturation event during the 72 hours immediately after ED discharge. One quarter of the children made at least one unscheduled visit, divided between primary care providers and return visits to the ED. Among those who returned for medical care, 34% received additional medications.

Among the 75 infants who experienced a desaturation event, 79% spent more than 1 minute with SpO2 levels ≤ 80%, and 39% experienced SpO2 levels ≤ 70% for more than 1 minute. Among patients with any desaturation, 24% made a return medical visit compared with 26% of children with no desaturation events, a difference that was not statistically significant. Likewise, rehospitalization occurred in one infant with desaturations and two infants without desaturations, also not statistically significant.

When children with and without major desaturation events were compared, the frequency of unscheduled medical visits was essentially the same (24% with a major desaturation, 25% without a major desaturation). Nor did a measure of cumulative hypoxia correlate with the frequency of unscheduled medical visits. The investigators concluded that most infants discharged from the ED with bronchiolitis experienced desaturation events, and these desaturation events did not correlate with subsequent medical visits or hospitalization.

Viewpoint

I imagine that most practitioners found these results quite surprising. I don't think the study authors are exaggerating when they say that concern about posthospitalization desaturation influences decisions by clinicians, especially without good epidemiologic data on the frequency of desaturations or whether they are clinically meaningful. This study shows that brief desaturations, and even sustained desaturations, are strikingly common among infants discharged from the ED with bronchiolitis. It also shows, at least in this population, that those desaturations appear to be clinically meaningless.

However, this is a single-center study, and as noted in an accompanying editorial,[2] the relatively small sample size may preclude identifying rare untoward events that occur along with desaturation. For that reason alone, it would be worth repeating this study or conducting a similar study in a larger population, as well as in different patient populations, to tease out any potential relationships between desaturation and clinical condition that might convince clinicians that monitoring SpO2 can be helpful in caring for patients with bronchiolitis.

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