Unexpectedly high peak expiratory flow rates in normal Greek children

Peak expiratory flow among healthy children aged 5-14 years in China

Background

Guidelines of the Global Initiative for Asthma recommend the use of peak expiratory flow (PEF) in the assessment and management of patients with asthma. However, normal PEF values for Chinese children have not been thoroughly investigated.

Methods

This was a cross-sectional study of 3,169 healthy children aged 5-14 years from research centers in five cities of China: Guangzhou, Suzhou, Chengdu, Xi'an, and Beijing. We established pediatric reference values for PEF using a mini peak flow meter. PEF values recorded by the mini peak flow meter were compared with those obtained using a spirometer.

Results

Height was the biometric variable with greatest correlation to PEF for both sexes. Significant differences were noted between males and females. The regression equation for boys was calculated as PEF =4.39× height (cm) -300.48 (R² =0.76, P<0.001); for girls, this equation was PEF =4.13× height (cm) -278.04 (R² =0.72, P<0.001). PEF values for Chinese children according to age were close to those of Irish, Turkish, and British children but were lower than those of children in Greece; PEF values according to height were similar to those of Turkish and Danish children but lower than values for children in Ireland.

Conclusions

We established normal PEF values and developed predictive equations using linear regression analysis for Chinese children aged 5-14 years, while Greece and Ireland references were inappropriate for Chinese children.

Los Angeles phonospirometry technique: creating a normogram that correlates with peak expiratory flow measurements in children

OBJECTIVE

Measurement of peak expiratory flow (PEF) is recommended in the assessment of patients with asthma. However, the use of PEF involves multiple barriers, which have limited its use. Phonospirometry, as assessed by a novel Los Angeles phonospirometry technique, has shown good correlation to standard PEF measurements in a pilot study on symptomatic patients with asthma. We sought to develop a normogram for phonospirometry, and to validate the PEF normogram.

METHODS

A convenience sample of asymptomatic children ages 3-17 years old was approached for participation in the Emergency Department. Sample size calculations determined that at least 30 children per age group (n = 450) were needed. Children were asked to perform PEF measurements and phonospirometry, measured as the length of time (in s) the child was able to chant "lalala" in a single breath.

RESULTS

510 children were enrolled. Spearman's rho between PEF and phonospirometry was 0.722. Phonospirometry correlated with both age and height, with a Spearman rho of 0.697 and 0.696, respectively. This was slightly lower than the correlation of PEF with age and height with Spearman rhos of 0.877 and 0.902, respectively. A normogram was developed for phonospirometry based on age and height.

CONCLUSIONS

This study determined normal value ranges for the Los Angeles phonospirometry technique for age and height, and also showed that the technique has good correlation with PEF. This technique may be used to assess a pediatric patient with an acute asthma exacerbation.

Free running asthma screening test

The free running asthma screening test (FRAST) was evaluated in 503 Sheffield schoolchildren aged 6 to 12 years and compared with responses to an asthma questionnaire. The FRAST measured peak expiratory flow rate (PEFR) before and at 1, 5, and 10 minutes after maximum voluntary running for at least 5 minutes in a standardised environment. A fall in PEFR of greater than 15% in at least two postexercise readings was defined as abnormal. Six (1%) children did not do the test and 69 (14%) failed to complete it. Of these, 14 were known asthmatics, 18 were not testable, and 37 were normal when retested. There were 14 abnormal FRAST results among 412 'normal' children who completed the test and 10 of these were subsequently diagnosed asthmatic. None of 14 children with an abnormal FRAST result had been identified as wheezy, chesty, or asthmatic in the questionnaire. In this sample there was, on average, one child in every school class with unrecognised exercise induced bronchospasm. The FRAST is an acceptable, feasible, and cost effective way of identifying such potential asthmatics at school.