ABSTRACT
Background: Impulse oscillometry is an effort-independenttechnique of assessment of airway resistance and reactance, andcan be performed in children unable to complete spirometry.Objective: To evaluate the utility of impulse oscillometry andspirometry for assessing asthma control in children.Study design: Prospective cohort study.Participants: Children aged 5-15 years, with mild to severepersistent asthma.Intervention: On each 3-monthly follow-up visit, clinicalassessment, classification of control of asthma, impulseoscillometry and spirometry were performed.Outcome: Utility of impulse oscillometry parameters [impedance(Z5), resistance (R5), reactance (X5) at 5 Hz, and R5-20(resistance at 20Hz -5Hz) (% predicted), and area of reactance(AX, actual values)] and FEV1 (% predicted) to discriminatebetween controlled and uncontrolled asthma was assessed byreceiver operating characteristic (ROC) curve. Association ofFEV1 and impulse oscillometry parameters over time withcontrolled asthma was evaluated by generalized estimatingequation model.Results: Number of visits in 256 children [mean (SD) age, 100(41.6) mo; boys: 198 (77.3%)], where both impulse oscillometryand spirometry were performed was 2616; symptoms werecontrolled in 48.9% visits. Area under the curve fordiscrimination between controlled and uncontrolled asthma byFEV1, AX, R5-20, Z5, R5, and X5 were 0.58, 0.55, 0.55, 0.52,0.52 and 0.52, respectively. FEV1 [OR (95% CI): 1.02 (1.01-1.03)]and AX [OR (95% CI): 0.88 (0.81-0.97)] measured over theduration of follow-up were significantly associated withcontrolled asthma.Conclusion: Spirometry and impulse oscillometry parametersare comparable in ascertaining controlled asthma. Impulseoscillometry being less effort-dependent may be performed formonitoring control of childhood asthma, especially in youngerchildren.
ABSTRACT
Objective: To avoid excessive oxygen exposure and achieve target oxygen saturation(SpO2) within intended range of 88%-95% among preterm neonates on oxygen therapy.Methods: 20 preterm neonates receiving supplemental oxygen in the first week of lifewere enrolled. The percentage of time per epoch (a consecutive time interval of 10 hours/day) spent by them within the target SpO2 range was measured in phase 1 followed byimplementation of a unit policy on oxygen administration and targeting in phase 2. In phase 3,oxygen saturation histograms constructed from pulse-oximeter data were used as dailyfeedback to nurses and compliance with oxygen-targeting was measured again. Results:48 epochs in phase 1 and 69 in phase 3 were analyzed. The mean (SD) percent time spentwithin target SpO2 range increased from 65.9% (21.4) to 76.5% (12.6) (P=0.001).Conclusion: Effectiveimplementation of oxygen targeting policy and feedback usingoxygen saturation histograms may improve compliance with oxygen targeting.
ABSTRACT
Objective: To determine whether fractional exhaled nitric oxide (FENO) has a utility as a diagnostic or predictive maker in acute exacerbations of asthma in children. Design: Analysis of data collected in a pediatric asthma cohort. Setting: Pediatric Chest Clinic of a tertiary care hospital Methods: A cohort of children with asthma was followed up every 3 months in addition to any acute exacerbation visits. Pulmonary function tests (PFT) and FENO were obtained at all visits. We compared the FENO values during acute exacerbations with those at baseline and those during the follow up. Results: 243 asthmatic children were enrolled from August 2009 to December 2011 [mean (SD) follow up - 434 (227) days]. FENO during acute exacerbations was not different from FENO during follow up; however, FENO was significantly higher than personal best FENO during follow up (P < 0.0001). FENO during acute exacerbation did not correlate with the severity of acute exacerbation (P=0.29). The receiver operating characteristics curve for FENO as a marker for acute exacerbation had an area under the curve of 0.59. Cut-off of 20 ppb had a poor sensitivity (44%) and specificity (68.7%) for acute exacerbation. Conclusions: FENO levels during acute exacerbation increase from their personal best levels. However, no particular cut off could be identified that could help in either diagnosing acute exacerbation or predicting its severity.