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Effect of supine posture on peak expiratory flow rates in asthma
1Department of Paediatrics, R K Khan Hospital, Durban, South Africa.
Insights
Supine posture significantly reduces peak expiratory flow rate (PEFR) in children with asthma, unlike in healthy children. This airflow obstruction resolves upon standing, suggesting posture alone can trigger asthma symptoms like nocturnal wheeze.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
Background:
- Asthma exacerbations, particularly nocturnal symptoms, are common in children.
- The impact of body posture on respiratory function in pediatric asthma is not fully understood.
Purpose of the Study:
- To investigate the isolated effect of supine posture on peak expiratory flow rate (PEFR) in asthmatic children.
- To compare PEFR changes in asthmatic children versus non-asthmatic controls when in a supine position.
Main Methods:
- 22 children with asthma and 15 non-asthmatic controls underwent PEFR measurements.
- Measurements were taken while standing and then at 30-minute intervals for up to 4 hours in a supine position.
- Tests were conducted in a controlled, low-stress environment to isolate postural effects.
Main Results:
- Asthmatic children exhibited a significant decrease in PEFR when in the supine position compared to controls.
- PEFR values returned to baseline levels upon resuming an upright posture without medication.
- The observed drop in PEFR was independent of asthma severity.
Conclusions:
- Supine posture alone can induce airflow obstruction in children with asthma.
- This postural effect may be a significant contributing factor to nocturnal wheezing and coughing in pediatric asthma.
- Posture management could be a consideration in managing asthma symptoms.
Abstract:
In order to determine the effect of supine posture alone on the peak expiratory flow rate (PEFR) in children with asthma, 22 children with asthma of varying severity had PEFR readings taken in the standing position and subsequently at 30 minute intervals in the supine position for a period of up to four hours. In order to minimise any stress factors no other procedures--for example, taking of blood specimens--were performed during the duration of the tests, which were carried out in a relatively dust free room with no curtains and minimal furniture. Fifteen non-asthmatic children acted as controls. The results showed a significant drop in the PEFR readings in the supine position in asthmatic children compared with the controls; this reverted back to baseline levels on assuming an upright posture at the end of the test without any medication. It is concluded that airflow obstruction can be induced by supine posture per se in asthmatic children; this may be a major factor contributing to nocturnal wheeze or cough.