Overreliance on Oximetry for Infants in ED, Study Suggests

Larry Hand

August 19, 2014

Pediatric emergency department (ED) physicians may be relying too much on oxygen saturation readings from pulse oximetry devices when deciding whether infants with bronchiolitis are hospitalized, according to an article published in the August 20 issue of JAMA.

Suzanne Schuh, MD, from the Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada, and colleagues conducted a randomized trial during 2008 to 2013 involving 213 otherwise healthy infants, aged 4 weeks to 12 months, with mild to moderate bronchiolitis and true oxygen saturations of 88% or higher.

The researchers note that bronchiolitis is the leading cause of infant hospitalization in the United States, accounting for annual costs of more than $1 billion.

The researchers randomly assigned the infants to 1 of 2 groups: 108 infants were assigned to true oxygen saturation readings and 105 to altered oximetry measures. The oximetry device manufacturer altered devices so that they would produce a reading 3% above true values.

The researchers did not inform ED physicians of the hypothesis of the study but did inform them that they had a 50% chance of having displayed saturations altered by a physiologically small amount and that true saturations were at least 88%. They also did not inform physicians of the magnitude or direction of altered readings.

The researchers found that 44 (41%) of the true oximetry group and 26 (25%) of the altered oximetry group were hospitalized within 72 hours or received more than 6 hours of ED care, for an absolute difference of 16% (95% confidence interval, 3.6% - 28.4%; P = 0.005). The effect remained significant after the researchers accounted for physicians as a random effect.

"Because the groups had similar severity and the adjustment for the experimental saturation resulted in lack of primary treatment effect, the difference in displayed saturations was likely the primary reason for the observed reduction in hospitalizations," the researchers write.

They note that most infants admitted to the hospital in this study had near-normal saturation levels or modest hypoxia, and that the limited number of infants is a significant limitation and did not allow them to set a threshold going forward.

The researchers also note, however, that previous studies have shown similar results in terms of oxygen saturation thresholds and hospital admissions.

"This suggests that oxygen saturation should not be the only factor in the decision to admit or discharge and may need to be reevaluated," they conclude.

Ethical Research?

In an accompanying editorial, Robert Vinci, MD, from the Department of Pediatrics at Boston Medical Center, Boston University School of Medicine, Massachusetts, and Howard Bauchner, MD, editor-in-chief of JAMA, ask the question: "Is it ethical to deceive physicians about real findings?"

"The authors did adhere to important principles of research," they write. "First, they obtained informed written consent from the parents, although not from the physicians. Second, the authors went to great length to ensure that the study was safe.... Displaying altered oximetry readings has been used in previous neonatal studies. There is unease when physicians are presented with artificially altered data, but for some research questions this may be necessary. For all research studies it is necessary to ensure that the study is safe and patients are fully informed of all risks."

How to treat young children with bronchiolitis has been uncertain and remains uncertain, they note, and the new study highlights the challenge ED physicians and primary care providers face.

They conclude, "[I]t is now clear that the oxygen saturation reading can influence decision making in ways that many clinicians have thought likely — overreliance on physiologic information of uncertain importance derived from a medical device. While physicians seek to improve the science of clinical decision making, the art of medicine and clinical assessment should not be trumped by overreliance on a single physiologic parameter. The care of patients with bronchiolitis will continue to improve as experienced physicians emphasize and continue to use a complete clinical evaluation and assessment as the most important element in the care of these infants and children."

This research was supported by the Thrasher Research Fund and the Physicians' Services Incorporated Foundation, and Masimo provided the oximeters used in the study. The authors and editorialists have disclosed no relevant financial relationships.

JAMA. 2014;312:699-700, 712-718.

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