Predicted normal values of pulmonary function tests in normal Korean children

PURPOSE: Pulmonary function tests are useful and important methods for evaluating patients with respiratory diseases. To assess lung function, we need to establish normal values of lung function, which vary according to population, age, gender and growth, particularly in children. This study was undertaken to establish normal predicted values of pulmonary function tests and to predict renewed reference values by spirometry in Korean school children. METHODS: Spirometric forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory flow at 25% to 75% of FVC (FEF25%-75%), and peak expiratory flow rate (PEFR) were measured in 406 healthy elementary school children (age, 6-12 years old) in May, 2012. Multiple linear regression analysis was performed for each spirometric parameter against age, height, weight and body surface area (BSA) separately for boys and girls, and derived reference equations and coefficients for all the spirometric parameters. RESULTS: All the measured spirometric parameters were significantly correlated with age, height, weight, and BSA. FVC was higher in boys aged 6-10 years than girls at ages matched. Height showed the highest correlation coefficient for all the spirometric parameters followed by BSA, weight and age in both genders. The normal predicted values of FVC and FEV1 at 130 cm in this study using renewed reference equations were approximately in the middle compared to previous studies. CONCLUSION: We reported here the renewed reference equations for normal predicted values of pulmonary function tests with high coefficients of determination based on updated data in healthy Korean children.

Factors associated with various clinical manifestations of Mycoplasma pneumonia in children

PURPOSE: Mycoplasma pneumonia (MP) is a major cause of community-acquired pneumonia in children and young adults. We aimed to investigate the factors that may influence on the clinical manifestations of MP in children. METHODS: A total of 109 admitted children from October 2011 to February 2012 were prospectively enrolled with physical examination and laboratory tests (complete blood count, C-reactive protein [CRP], and particle agglutinin assay). The diagnosis of MP was made when there was an infiltration on the chest X-ray and the particle agglutination test was once over 1:640 or showed 4-fold increase in serial tests. They were grouped by age, fever duration after treatment, presence of pleural effusion and wheezing. RESULTS: Preschool children showed shorter duration of fever (P=0.001), more wheezing (P3 days) and pleural effusion were developed in children with higher CRP (P=0.018 and P=0.007). Wheezing has been developed in children with younger age (P=0.007). CONCLUSION: Younger age was a risk factor to develop wheezing in MP and prolonged fever and pleural effusion were more likely to develop in children with higher CRP.

Comparison of Clinical Manifestation and Laboratory Findings between H1N1 and Influenza B Infection / 소아알레르기및호흡기학회지

PURPOSE: Influenza virus is one of the most important viruses that cause the respiratory infection seasonally. In April 2009, H1N1 was detected in America and Mexico and then there was pandemic in Korea. We investigated the difference of clinical and laboratory findings between the infections of H1N1 and Influenza B. METHODS: We have retrospectively studied the patients under age of 15 years who visited Inje University Sanggye Paik Hospital from August 2009 to April 2010. Evaluation for influenza infection was performed by rapid antigen test or multiplex reverse transcriptase polymerase chain reaction. Complete blood count with differential counts, C-reactive protein and chest X-ray were checked. RESULTS: Enrolled patients were 2,226 in H1N1-infected group and 288 in influenza B-infected group. Seasonal variation was that H1N1 in autumn and winter but influenza B in spring. The male-to-female sex ratio was same as 1.23 in each group. The mean age of H1N1-infected group was higher than influenza B-infected group (P<0.001). Fever was developed similarly in both groups (P=0.114). However, cough, sputum, rhinorrhea, vomiting, diarrhea, and headache were more prevalent in influenza B infection compared to H1N1 infection (P<0.001). Pneumonia development and admission rate were higher in influenza B infection compared to H1N1 infection (P<0.001, respectively). CONCLUSION: Although H1N1 infection spread rapidly, H1N1 caused not so severe symptoms than influenza B. Because of the possibility that influenza epidemic will develop repeatedly in the future, we need to evaluate more about different characteristics depending on the virus subtype and prepare for them.