High Concentration Oxygen Therapy in Pediatric Asthma Leads to Higher CO2 Levels

pediatric asthma with nebulizer
In pediatric patients with moderate to severe asthma exacerbations, a titrated oxygen regimen that only administers oxygen therapy to patients with proven hypoxemia should be considered.

In pediatric patients with moderate to severe asthma exacerbations, the use of titrated oxygen therapy (TOT) decreases the risk for hypercapnia compared with the use of high concentration oxygen therapy (HCOT). Moreover, an association was demonstrated between lower asthma scores and hospital admissions in patients treated with a TOT regimen in contrast to HCOT, according to study results published in Pediatric Pulmonology.

In this prospective randomized controlled clinical trial conducted in the pediatric emergency department (ED) of the Children’s Hospital at Montefiore in the Bronx, New York, investigators sought to compare the effects of HCOT vs TOT with a target oxygen saturation between 92% and 95% on the transcutaneous carbon dioxide (PtCO2) measurement in pediatric patients who had presented to the ED with a moderate or severe asthma exacerbation, which was defined as an Asthma Score of >5.

Patients eligible for the study were between age 2 and 18 years with a history of asthma. PtCO2 and asthma scores were measured at 0 minutes (baseline), 20 minutes, 40 minutes, and 60 minutes, and then every 30 minutes until disposition decision. The primary study outcome was a change in PtCO2. Secondary study outcomes included hospital admission rate and change in asthma score. A total of 96 patients were enrolled in the study: 49 in the HCOT group and 47 in the TOT group. The mean participant age was 8.27 years.

Results of the study showed that PtCO2 at 0 minutes was similar in both arms (35.33+ 3.875 mm Hg with HCOT vs 36.66+4.69 mm Hg with TOT; P =.13). In contrast, PtCO2 at

60 minutes was significantly higher in the HCOT group vs the TOT group (38.08+5.11 mm Hg vs 35.51+4.57 mm Hg, respectively; P =.01).

At baseline, the asthma score was similar in both arms (7.55+1.34 with HCOT vs 7.30+1.18 with TOT; P =.33). At 60 minutes, however, the asthma score was significantly lower in the TOT group compared with the HCOT group (3.57+1.25 vs 4.71+1.38, respectively; P =.0001). Furthermore, the rate of hospital admissions was higher in the HCOT arm compared with the TOT arm (40.5% vs 25.5%, respectively; odds ratio, 2.19; 95% CI, 0.889-5.41; P =.088).

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The investigators concluded that the use of HCOT in children experiencing an asthma exacerbation leads to significantly higher carbon dioxide levels, which, in turn, increases asthma scores and trends toward higher rates of hospital admission. Thus, they recommend the utilization of a TOT regimen in these patients. Larger studies are warranted in order to validate these findings.


Patel B, Khine H, Shah A, Sung D, Medar S, Singer L. Randomized clinical trial of high concentration versus titrated oxygen use in pediatric asthma [published online April 3, 2019]. Pediatr Pulmonol. doi:10.1002/ppul.24329