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Pepsin measured in induced sputum--a test for pulmonary aspiration in children?
Evelyn Ervine1, Cyril McMaster, William McCallion
1Respiratory Research Group, Queen's University Belfast, Northern Ireland, UK. evelynervine@hotmail.com
Insights
Pepsin detection in induced sputum is not a reliable marker for pulmonary aspiration in children. Sputum induction itself appears to trigger gastroesophageal reflux (GER), invalidating the test for diagnosing reflux-related respiratory issues.
Area of Science:
- Pediatric Pulmonology
- Gastroenterology
- Diagnostic Biomarkers
Background:
- Gastroesophageal reflux (GER) can cause respiratory symptoms in children.
- Pepsin in sputum is a potential indicator of pulmonary aspiration due to GER.
- Sputum induction is a common method for obtaining respiratory samples.
Purpose of the Study:
- To evaluate pepsin in sputum as a marker for pulmonary aspiration secondary to GER in children.
- To determine if sputum induction procedure itself can induce GER, potentially invalidating results.
- To test the hypothesis that healthy children lack detectable pepsin in induced sputum.
Main Methods:
- Recruited children (aged 4-16) from surgical outpatient clinics.
- Obtained sputum via hypertonic saline induction after spirometry.
- Measured pepsin concentration using an in-house enzyme-linked immunosorbent assay (lower limit of detection: 1.19 ng/mL).
Main Results:
- Pepsin was detected in 85% (17 of 20) of sputum samples from children.
- No adverse effects were reported during the sputum induction procedure.
- The study included 20 children who completed the protocol.
Conclusions:
- Sputum induction appears to induce physiological GER in healthy children.
- Measuring pepsin in sputum obtained via induction is not a useful method for investigating reflux-related respiratory disease.
Purpose:
The purpose of this study was to investigate if pepsin measured in sputum is a useful marker of pulmonary aspiration secondary to gastroesophageal reflux (GER) in children. It is possible that the induced sputum procedure could cause GER and invalidate the results. The hypothesis stated that healthy children (those without history of respiratory or gastroesophageal symptoms) would not have pepsin detected in induced sputum.
Methods:
Children attending surgical outpatients in the Royal Belfast Hospital for Sick Children (Belfast, Northern Ireland) were recruited. After spirometry, sputum was obtained by induction with hypertonic 3% saline. Spirometry was repeated, and complications were noted. An "in-house" enzyme-linked immunosorbent assay was used to measure pepsin concentration in sputum. The lower limit of detection of pepsin was 1.19 ng/mL.
Results:
Children (n = 21) aged 4 to 16 years were recruited. Twenty children completed the study. No adverse effects were reported. Pepsin was detected in 17 (85%) of 20 sputum samples.
Conclusions:
The act of sputum induction appears to induce physiologic GER in a healthy childhood population. The analysis of pepsin in sputum obtained by sputum induction is therefore not useful in the investigation of reflux-related respiratory disease.
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