Pulse Oximetry and Peak Expiratory Flow Rate Correlations in Acute Asthma Exacerbation in Children

Abstract

Background: The relationship between oxygen saturation (SpO₂ ) and peak expiratory flow rate (PEFR) in patients with acute asthma is  variable.

Aim: This study aims to assess the predictive value and correlation of this relationship in identifying children with mild  symptoms of asthma exacerbation and defining their role in guiding early intervention decision-making.

Patients and Methods: This  was a retrospective review of the register of children with asthma seen at the respiratory clinic of a tertiary center in Nigeria from April  2014 to February 2020. Information on their biodata, medical history, clinical status, baseline SPO₂, and %predicted PEFR was retrieved  and analyzed.

Results: The mean values for participants with no symptoms and those with mild symptoms of asthma exacerbation were respectively: SpO₂ was 97 ± 1.6% and 96 ± 2.6% (MD: 1.2; 95% CI; 0.7–1.7, P < 0.001); %predicted PEFR: 77.8 ± 17.8 and 64.1 ± 23 (MD;  13.68; 95% CI; 7.3 to 20.0, P < 0.001). Among those with uncontrolled asthma who were having mild symptom exacerbation of their  asthma, the correlation between SpO₂ and %predicted PEFR was significantly moderate (r = 0.44, P = 0.04). Children with SpO₂ between  the range of 92%–95% were significantly more likely to have mild symptoms of asthma exacerbation (OR: 2.52,95% CI: 1.22, 5.2, P = 0.01) compared to those with SpO₂ >95%.

Conclusion: Children with SpO₂ of <95% are more likely to have an acute asthma exacerbation. While  SpO₂ and PEFR have more role in identifying children without acute asthma exacerbation and a limited role in identifying children  with mild symptoms of asthma due to their exacerbation due to their moderate to poor correlation.