Tool Predicts Length of Hospital Stay for Pediatric Asthma

Ingrid Hein

November 16, 2020

A new tool can predict when an asthma exacerbation will put a child in the hospital for 2 days or more, researchers report.

Jose Rojas Camayo

"Heart rate, respiratory rate, and oxygen saturation levels with percentile-based cutoffs are independent predictors of hospital stays in children," said Jose Rojas Camayo, MD, from the University of Texas Medical Branch in Galveston.

Previous ranges for heart and respiratory rates were "based on empirical data rather than evidence-based data," Camayo said during his presentation at the American College of Allergy, Asthma & Immunology 2020 Annual Scientific Meeting, where the study was given first place for the best fellow-in-training study in the Clemens von Pirquet awards.

In 2011, evidence-based centile charts for children were developed from a systemic review of 69 observational studies that looked at heart rate data for 143,346 children and respiratory rate data for 3,881 children.

That review, which was aimed at helping clinicians update clinical and resuscitation guidelines, showed changes according to age. "As children get older, they tend to have lower values of respiratory rate," Camayo explained.

For their retrospective analysis, he and his colleagues evaluated whether the centile-based approach — with oxygen saturation, heart rate, and respiratory rate — can be used predict length of hospital stay for children admitted for asthma exacerbation.

They examined the charts of 695 children, 2 to 18 years of age, who were hospitalized at the Lincoln Medical Center in Bronx, New York. The mean hospital stay was 43.3 hours (range, 5 - 183 hours).

To create a model with the best cutoff rates, the researchers grouped patients into two categories: children who stayed in the hospital less than 2 days, and those who stayed 2 days and longer. They then explored Pediatric Advanced Life Support (PALS) cutoff values and oxygen saturation.

Cutoffs based on percentiles were able to predict risk for hospital stays longer than 2 days in children who experienced asthma exacerbation.

Model Most Predictive of Risk for Prolonged Hospitalization
Variable Odds Ratio 95% CI
Oxygen saturation < 95% 1.955 1.307–2.926
Heart rate >10 beats above the 99th percentile 1.578 1.127–2.210
Respiratory rate >5 breaths above the 99th percentile 1.454 1.038–2.035

Each factor put a child at greater risk for a longer hospital stay. "With more factors present, the rate of hospitalization of more than 2 days increases," Camayo explained. "If we have these three factors present, the rate of hospitalization for more than 2 days is about 85%; if we have only one, it's around 30%; and if we have none, around it's 23%."

Important to Pediatric Treatment Plan

Stanley Fineman

"Knowing that a patient is at greater risk for prolonged hospitalization can be helpful in planning their treatment," said Stanley Fineman, MD, from the Emory University School of Medicine in Atlanta.

"The data from this study show that asthmatic children with poorer Pediatric Advanced Life Support reference values — including lower oxygen saturation and higher heart and respiratory rates — were at greater risk for longer hospitalization. This is important since it suggests that these parameters can help predict which children are sicker and may require more intensive treatment during their hospitalization," he added.

"Although one might consider this 'obvious', it is always helpful to back it up with data. Potentially, the patient's treatment can be adjusted, or 'beefed-up,' in those with increased risk of prolonged length of stay," Fineman said.

Camayo and Fineman have disclosed no relevant financial relationships.

American College of Allergy, Asthma & Immunology (ACAAI) 2020 Annual Scientific Meeting: Abstract A027. Presented November 15, 2020.

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