The purpose of this study is to evaluate the association of spirometry, Forced Expiratory Volume in 1 second(FEV1) and Forced Vital Capacity(FVC), with airway resistance via Impulse Oscillometry at 5 Hz(RAW) in assessing asthmatic pediatric patients.
We retrospectively reviewed 84 patient charts with a diagnosis of asthma. The patients were coached to breath passively. Artifacts caused by cough or swallowing show increased resistance. We reviewed the charts for the following parameters: age, sex, percent predicted of FEV1, (value <80% predicted is abnormal), percent predicted of FVC, (value<80& is abnormal), percent predicted of RAW, (value >150% is abnormal), maintenance inhaled steroids, and diagnosis.
The age ranged from 5 years old to 18 years old. 43(51.2%) of the patients were female and 41(48.8%) were male. 76(90.5%) of the patients had an RAW<150%. Of the patients with a normal RAW, 20(26.3%) had a FEV1<80% only, 2(2.6%) had a FVC <80% only, and 5(6.6%) had both an FEV1 and FVC<80%. Of the 8(9.5%) patients with an RAW>150%, 2(25%) had an FEV1<80% only, 3(37.5%) had both an FEV1 and FVC<80%, and 3(37.5%) of the patients had both an FEV1 and FVC>80%. All of the patients wih an RAW >150% were on maintenance inhaled steroids and had a diagnosis of moderate persistent asthma. Overall, 70(83.3%) patients had a diagnosis of moderate persistent asthma and 14(16.7%) patients had a diagnosis of mild persistent asthma. None of the patients were ill when testing.
In this study, a patient’s FEV1 and FVC were not associated with RAW. RAW could not be predicted by FEV1 and FVC. An increased RAW was not associated with a decreased FEV1 and FVC.
Spirometry and Impulse Oscillometry should be used together along with clinical history in evaluating patients for asthma. Impulse oscillometry alone should not be used in assessing asthma until further studies have been performed. Further studies are needed to evaluate the role of Impulse Oscillometry in relation to Spirometry when assessing asthmatic pediatric patients.
Khalila Lewis-Brown, None.