A comparison between impulse oscillometry system and spirometry for spirometry for detecting airway obstruction in children / 소아과

PURPOSE: Measurement of forced expiratory volume in 1 second (FEV1) is usually difficult to obtain in children under six years of age because it requires active cooperation. This study evaluates the sensitivity of impulse oscillometry system (IOS) parameters for detecting airway obstruction in comparison with FEV1. METHODS: We studied 174 children who performed the lung function and methacholine challenge tests to diagnose asthma by IOS and spirometry. Children were divided into two subgroups according to their PC20, which is a parameter for bronchial sensitivity. We compared IOS parameters with FEV1 at the baseline, post-methacholine challenge, and evaluated their correlation. RESULTS: At the baseline, reactance at 5 Hz (X5) and resistance at 5 Hz (R5) significantly differed between the PC20 positive (PC2016 mg/mL) group; however, FEV1, FEV1% predicted, FEV1_Zs (Z score) did not differ. FEV1 is correlated with X5 (r=0.45, P<0.01) and R5 (r=-0.69, P<0.01). FEV1_Zs is also correlated with X5_Zs (r=-0.26, P<0.01) and R5_Zs (r=-0.31, P<0.01). After the methacholine challenge test, dose-response slopes in FEV1 and X5 significantly differed between the two subgroups (P<0.05). CONCLUSION: IOS parameters were more discriminative than FEV1 for detecting decreased baseline lung function between two subgroups and have a good correlation with FEV1.

Safety and efficacy of the ultra-rush immunotherapy with extracts of Dermatophagoides pteronyssinus in children / 소아과

PURPOSE: Immunotherapy is accepted as the only treatment of allergic disease that can modify the natural course of the disease and ameliorate symptoms. This study aimed to evaluate the safety and efficacy of ultra-rush therapy using Dermatophagoides extracts in children. METHODS: Of children older than four years who had visited Bundang CHA Pediatric Allergy Clinic, those showing positive reactions only to Dermatophagoides in the skin prick test and to the nasal provocation test were included. In all, 11 and 12 patients respectively preferred conventional and ultra-rush immunotherapy. We elevated allergen concentrations diluted to 1,000:1 of the end strength by 2-3 times with 30-minute intervals and checked oxygen saturation, pulse rate, blood pressure, and systemic reactions every 15 minutes. Immunotherapy effectiveness was valued by changes in nasal provocation test scores before and after immunotherapy. RESULTS: The average ages of patients in the conventional and ultra-rush immunotherapy groups were 8.3+/-2.3 and 9.2+/-2.8 years, respectively. Systemic reactions were observed in six in the ultra-rush group (50%) without anaphylaxis and one (9%) in the conventional group. The average scores in the nasal provocation test before and after treatment in the conventional group were 8.2+/-1.5 and 4.6+/-2.1, respectively (P=0.043). In the ultra-rush immunotherapy group, the scores changed from 6.2+/-2.2 to 3.7+/2.5 (P=0.017). CONCLUSION: Ultra-rush immunotherapy using Dermatophagoides in children is effective for treating allergic disease but can induce systemic effects rather than conventional immunotherapy.

Reference values for respiratory system impedance using impulse oscillometry in school-aged children in Korea / 소아과

PURPOSE: The impulse oscillometry (IOS) is applicable to young children because it requires minimal cooperation and a non-invasive method to measure the mechanics of respiratory system. This study aimed to develop the reference values in school-aged children in Korea, using IOS which is a modification of forced oscillation technique (FOT). METHODS: Measurements were performed in 92 previously untrained healthy children, aged 7 to 12 years old, using IOS. We analyzed the relationships between the data about their age, height, weight, body surface area (BSA), body mass index (BMI) and the result of IOS using the linear regression test. RESULTS: The success rate of IOS was 92.4%. Stepwise multiple regression of resistance of respiratory system (Rrs) and reactance of respiratory system (Xrs) in natural form for age, height, weight, BSA, BMI showed that height was the most significant predictor and altogether of 5 variables explained the Rrs and Xrs most. Our regression equations at multiple frequencys were comparable to published reference values, especially about the Rrs obtained at 5 Hz. CONCLUSION: IOS is a feasible method to measure the respiratory resistance in untrained children. We got the reference values using IOS and it seems to be useful to diagnose a variety of respiratory diseases.

Assessment of Time Interval Between Onset of Ventricular Inflow and Onset of Early Diastolic Velocity by Tissue Doppler in Normal Infants

PURPOSE: Recently, time interval between onset of transmitral early inflow (E) and onset of early diastolic (Ea) velocity of the mitral annulus (TE-Ea) has been used to identify diastolic dysfunction in adults, but to date, no studies have been done in infants. The purpose of our study was to evaluate the normal values of TE-Ea in infants under 1 year of age, and to assess the influence of age, heart rate and cardiac growth on this index. METHODS: Thirty healthy children (mean+/-SD, age; 5.4+/-2.3 months) underwent echocardiography. Mitral and tricuspid inflow and tissue Doppler velocities were obtained from the leaflet tips and lateral site of the annulus, respectively, in the apical four-chamber view. The time intervals between the peak of R wave and onset of mitral and tricuspid E velocity (T(E)) and between peak of R wave and onset of Ea velocity (T(Ea)) were measured. The differences between these time intervals were calculated as T(E-Ea), which were compared with demographic and echocardiographic variables. RESULTS: Mean heart rate was 125.27+/-10.78 (bpm). Mitral T(E-Ea) was shorter than tricuspid T(E-Ea) (mean+/-SD, 24.89+/-10.33 msec versus 32.43+/-12.72 msec, P=0.016). Both mitral and tricuspid T(Ea) were significantly greater than T(E) (both: P<0.01). Age and heart rate did not show correlation with T(Ea-E). When correlated with echocardiographic variables, mitral T(E-Ea) tended to decrease as mitral ring area increased. CONCLUSION: In normal infants, T(E-Ea) values differ between both ventricles, which suggest differences in ventricular adaptation in the first year of life.