Related Experiment Videos
Sensitivity of spirometric measurements to detect airway obstruction in infants
Marcus H Jones1, John Howard, Stephanie Davis
1Department of Pediatric Pulmonary and Critical Care, Indiana University School of Medicine, James Whitcomb Riley Hospital for Children, 702 Barnhill Drive, Room 4270, Indianapolis, Indiana 46202-5225, USA.
Insights
Forced expiratory flow volume curves effectively assess infant airway function. Flow measures, particularly FEF50, better detect abnormal lung function than timed volumes in infants with respiratory symptoms.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Assessing infant airway function is crucial for diagnosing and managing respiratory conditions.
- Current methods may have limitations in differentiating varying severities of respiratory symptoms in infants.
Purpose of the Study:
- To evaluate the utility of forced expiratory flow volume curves from raised lung volumes in assessing airway function in infants.
- To compare the sensitivity of flow measures versus timed volume measures in detecting abnormal lung function.
Main Methods:
- Infants were divided into two groups: those with previous respiratory symptoms (Group 1) and those currently symptomatic (Group 2).
- A control group of healthy infants was used for comparison.
- Flow volume curves were analyzed using forced vital capacity (FVC), forced expiratory flow at 50% (FEF50), 75% (FEF75), and 25-75% of FVC (FEF25-75), and forced expiratory volume in 0.5 seconds (FEV0.5) and FEV0.5/FVC ratio, all expressed as Z scores.
Main Results:
- All measured variables, except FVC, showed significantly negative Z scores, distinguishing symptomatic infants from asymptomatic ones.
- Flow variables (FEF50, FEF75, FEF25-75) exhibited more negative Z scores than timed expiratory volumes (FEV0.5, FEV0.5/FVC) in both infant groups.
- FEF50 demonstrated the highest performance in identifying abnormal lung function, with flow measures generally detecting more abnormalities than timed volume measures.
Conclusions:
- Forced expiratory maneuvers using the raised volume rapid compression technique can effectively differentiate infant groups based on respiratory symptom severity.
- Measures of forced expiratory flow are superior to timed expiratory volume in detecting abnormal airway function in infants.
Abstract:
We evaluated the ability of forced expiratory flow volume curves from raised lung volumes to assess airway function among infants with differing severities of respiratory symptoms. Group 1 (n = 33) had previous respiratory symptoms but were currently asymptomatic; group 2 (n = 36) was symptomatic at the time of evaluation. As a control group, we used our previously published sample of 155 healthy infants. Flow volume curves were quantified by FVC, FEF50, FEF75, FEF25-75, FEV0.5, and FEV0.5/FVC, which were expressed as Z scores. All variables except FVC had Z scores that were significantly less than zero and distinguished groups 1 and 2 with progressively lower Z scores. The mean Z scores of the flow variables (FEF50%, FEF75%, and FEF25-75%) were more negative than the Z scores for the timed expired volumes (FEV0.5 or FEV0.5/FVC) for both groups. In general, measures of flow identified a greater number of infants with abnormal lung function than measures of timed volume; FEF50 had the highest performance in detecting abnormal lung function. In summary, forced expiratory maneuvers obtained by the raised volume rapid compression technique can discriminate among groups of infants with differing severity of respiratory symptoms, and measures of forced expiratory flows were better than timed expiratory volume in detecting abnormal airway function.