Performance of Bedside Lung Ultrasound by a Pediatric Resident: A Useful Diagnostic Tool in Children With Suspected Pneumonia.

OBJECTIVES: Recent studies suggest that lung ultrasound is a good, radiation-free alternative to chest radiography in children with pneumonia. We investigated how bedside lung ultrasound performed by a pediatric resident compared with chest radiography in children with suspected pneumonia. METHODS: This was a prospective study comparing bedside lung ultrasound to chest radiography as the reference standard. Children aged 0 to 15 years with suspected pneumonia at a pediatric emergency department were included and underwent chest radiography and lung ultrasound. A pediatric resident with minimal practical ultrasound experience and with no access to supervision performed the bedside lung ultrasound and was blinded to the patients' medical evaluation. RESULTS: A total of 82 children underwent both chest radiography and lung ultrasound (57% boys; median [interquartile range] age, 1.5 [1.1-2.5] years). The lung ultrasound took 7 to 20 minutes to perform, and 10% were of suboptimal quality due to an uneasy child. The prevalence of consolidations by chest radiography was 50%. Lung ultrasound had a sensitivity of 40% (95% confidence interval [CI], 30%-51%), specificity of 91% (95% CI, 83%-96%), positive likelihood ratio of 4.71 (95% CI, 2.21-10.04), and negative likelihood ratio of 0.65 (95% CI, 0.54-0.79). CONCLUSIONS: Bedside lung ultrasound is a useful tool, with a good specificity, to find lung consolidations in children even when the sonologist has minimal practical ultrasound experience and no access to supervision. We suggest the use of bedside lung ultrasound as a diagnostic tool in children with suspected pneumonia.

Accuracy of whole-body plethysmography requires biological calibration.

BACKGROUND: Specific airway resistance (sRaw) measured by whole-body plethysmography in young children is increasingly used in research and clinical practice. The method is precise and feasible. However, there is no available method for calibration of the resistance measure, which raises concern of accuracy. Our aim was to determine the agreement of sRaw measurements in six centers and expand normative sRaw values for nonasthmatic children including these centers. METHOD: Identical hardware with different software versions was used at the six centers. Measurements followed a standard operating procedure: (1) seven healthy young children were brought to each of the six centers for sRaw measurements; and (2) 105 healthy preschool children (52 boys; mean age, 5.1 years; interquartile range, 4.3 to 6.0) were recruited locally for sRaw measurements. RESULTS: (1) The sRaw of the seven-children study group was significantly lower at two centers compared with the other four centers, and one center had significantly higher sRaw than all the other centers (p < 0.05). Error in the factory settings of the software was subsequently discovered in one of the deviating centers. (2) Normative data (105 preschool children) were generated and were without significant difference between centers and independent of height, weight, age, and gender. We subsequently pooled these normative data (105 children) with our previous data from 121 healthy young children (overall mean sRaw, 1.27; SD, 0.25). CONCLUSION: Control using biological standards revealed errors in the factory setting and highlights the need for developing methods for verification of resistance measures to assure accuracy. Normative data were subsequently generated. Importantly, other centers using such normative data should first consider proper calibration before applying reference values.

Exhaled nitric oxide in healthy young children during tidal breathing through a facemask.

The aim of this study was to establish reference values and to examine day-to-day and within-day variations of exhaled nitric oxide (eNO) during tidal breathing in healthy children using a newly described method. Exhaled NO was measured on-line and off-line during tidal breathing through a facemask. In a subgroup of children measurements were repeated during the course of a single day and on the same time on three consecutive days. A total of 133 healthy children were included in the study and measurements were obtained from 121 children aged 2-7 yr (61 boys and 60 girls). The geometric mean eNO concentration and 95% CI was 3.9 (3.5-4.2) parts per billion (p.p.b.) for on-line measurements and 3.0 (2.7-3.3) p.p.b. for off-line measurements. Exhaled NO was independent of gender, age, height and weight. The 95% reference intervals (RI) for on-line and off-line measurements were 1.2-8.2 and 1.3-7.1 p.p.b. respectively. Twenty-three children completed measurements of within-day and day-to-day variations, none of which showed significant variation. In conclusion, the established reference values and data on variability within and between days may facilitate the clinical application for measurement of eNO during tidal breathing in young children.

Measurement of exhaled nitric oxide in young children during tidal breathing through a facemask.

Measurement of exhaled nitric oxide (eNO) offers a non-invasive means for assessment of airway inflammation. The currently available methods are difficult to apply in preschool children. We evaluated four methods potentially applicable for eNO measurement during tidal breathing in young children. eNO was assessed during tidal breathing in 24 children, 2-7 yr old, using a facemask which separated nasal and oral airflow. Facemasks with and without a one-way valve allowing exhalation through the nose were used. Expiratory flow control was not attempted. Measurements of eNO were performed both on-line and off-line. In 11 children, 8-12 yr old, measurements were compared with the standard single breath on-line method. eNO was significantly lower applying the one-way valve in on-line and off-line measurements in comparison with measurements without the valve [4.6 and 3.9 parts per billion (ppb) vs. 6.9 ppb and 6.5 ppb]. The mean within subject coefficient of variation (CV) was significantly lower in on-line measurements with the one-way valve (9.6%) compared with the other three methods (18.8, 27.7 and 29.3% respectively). Measurements with a facemask fitted with a one-way valve yielded similar eNO levels as the standard single breath method (7.0 ppb vs. 6.9 ppb) and reproducibility (9.8% vs. 7.1%). In conclusion, reproducible measurements of eNO can be obtained without control of expiration flow using a facemask fitted with a one-way valve on the nasal compartment. The likely explanation to this is that the one-way valve reduces the admixture of nasal NO, thereby improving the reliability of eNO measurements.

Serial lung function and responsiveness in cystic fibrosis during early childhood.

In a 4-year prospective study, we evaluated specific airway resistance (sRaw) by whole-body plethysmography, respiratory resistance by the interrupter technique, and respiratory resistance and reactance at 5 Hz by the impulse oscillation technique combined with measurement of responsiveness to bronchodilators and cold air in 30 children (mean [range] age 5.7 [2 to 8] years) with cystic fibrosis (CF). Spirometry was done at school age. Mean sRaw was consistently abnormal: the mean z score (SD) was 2.52 (2.02) (p < 0.001) at the start and was unchanged 36 months later at 2.74 (2.02). Mean z score (SD) for FEV(1) at first satisfactory measurement, at a mean age (range) of 6.1 (4.9-7.5) years was -1.2 (1.2) and was further reduced to -1.85 (1.2) 4 years from inclusion at a mean age (range) of 9.9 (6.8-12) years. Neither respiratory resistance by the interrupter technique nor the impulse oscillation technique demonstrated consistent abnormal levels. Patients with CF as a group did not differ from healthy subjects in responsiveness to bronchodilators and cold air. sRaw may be a useful tool in CF during early childhood. Reduced lung function was documented from consistently abnormal levels of sRaw and FEV1 during the study. Bronchodilator responsiveness and response to cold air challenge were normal.