Related Experiment Videos
Sampling of exhaled nitric oxide in children: end-expiratory plateau, balloon and tidal breathing methods compared
Q Jöbsis1, S L Schellekens, A Kroesbergen
1Dept. of Paediatrics, Erasmus University Medical Centre/Sophia Children's Hospital, Rotterdam, The Netherlands.
Insights
The balloon method for measuring exhaled nitric oxide (NO) in children with asthma is comparable to the standard method. This simple technique allows for NO assessment in young children without specialized equipment.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Biomedical Engineering
Background:
- Exhaled nitric oxide (NO) is a marker of airway inflammation in asthma.
- Current standard methods for NO measurement require controlled exhalation, which can be difficult for children.
- Simpler, child-friendly methods are needed for accurate NO assessment in pediatric asthma.
Purpose of the Study:
- To compare exhaled NO concentrations from a standard controlled exhalation method with two simpler methods: blowing into a balloon and tidal breathing.
- To evaluate the feasibility and agreement of these alternative methods in children with allergic asthma.
Main Methods:
- 101 stable allergic asthmatic children performed duplicate measurements using: 1) standardized slow exhalation (20% vital capacity/sec) with biofeedback, 2) single exhalation into a mylar balloon, and 3) 2-minute tidal breathing through a mouthpiece.
- Exhaled NO was measured using a chemiluminescence analyzer.
- Agreement was assessed using intraclass correlation coefficients (ICC).
Main Results:
- 29% of children could not perform the standardized slow exhalation for at least 3 seconds.
- All children successfully completed the balloon and tidal breathing methods.
- Exhaled NO levels were similar between the standard method (5.3 ppb) and the balloon method (5.2 ppb) (ICC=0.73).
- Tidal breathing yielded significantly higher NO levels (8.0 ppb) with lower agreement (ICC=0.53) and suggested nasal contamination.
Conclusions:
- The balloon method provides exhaled NO measurements comparable to the standard end-expiratory plateau method in asthmatic children.
- The balloon method is a simple, cost-effective, and feasible alternative for assessing exhaled NO in children, especially when specialized equipment is unavailable.
- Tidal breathing is less reliable due to potential nasal air contamination.
Abstract:
The aim of this study was to compare exhaled nitric oxide concentrations obtained during controlled slow exhalation, presently considered as the method of choice, with two sampling methods that are easily performed by children: blowing air into a balloon and tidal breathing through a mouthpiece. One hundred and one well controlled, stable allergic asthmatic children (median age 11.7 yrs) performed the following tasks in duplicate: 1) exhalation from total lung capacity through a mouthpiece against a resistor with a standardized flow rate of 20% of the subject's vital capacity per second, using a biofeedback system; 2) a single deep exhalation into an NO-impermeable mylar balloon; and 3) tidal breathing through a low resistance mouthpiece over 2 min. NO was measured using a chemiluminescence analyser. Twenty-nine children (29%) were not able to perform a constant-flow exhalation of at least 3 s. All children performed the balloon and tidal breathing methods without difficulty. NO concentrations (means +/-SEM) were 5.3+/-0.2 parts per billion (ppb) at the end-expiratory plateau, 5.2+/-0.3 ppb in balloons (intraclass correlation coefficient (r(i)) = 0.73) and 8.0+/-0.4 ppb during tidal breathing (p<0.001, r(i) = 0.53 compared to plateau values). Mean values of NO during tidal breathing increased significantly with time, suggesting increasing contamination with nasal air. It was concluded that, in asthmatic children, the end-expiratory plateau concentration of nitric oxide during exhalation at 20% of the vital capacity per second is similar to the values obtained with the balloon method, with satisfactory agreement, but differs from values obtained during tidal breathing. The balloon method is cheap, simple and offers the interesting possibility to study exhaled nitric oxide in young children independently of the presence of a nitric oxide analyser.