G. Michael Davis

Long-term pulmonary sequelae of severe bronchopulmonary dysplasia.

OBJECTIVE To evaluate the long-term pulmonary sequelae of survivors of bronchopulmonary dysplasia (BPD) of sufficient severity to have required supplemental oxygen for at least 1 month after term. STUDY DESIGN Fifteen patients with a mean age of 1.1 years were matched to preterm infants of similar gestational age and age at time of study. Pulmonary function testing included spirometry, plethysmographic lung volumes, carbon monoxide diffusion capacity, and in 9 of 15 subjects with BPD, measurement of lung static elastic recoil pressures. RESULTS The subjects with BPD had a mean expiratory volume in 1 second (FEV1) of 64% +/- 21% predicted (4 had an FEV1 < 50% predicted) compared with 85% +/- 11% (P < .01) for the preterm children in the control group. Subjects with BPD had a significant degree of gas trapping with a residual volume to total lung capacity ratio of 37% +/- 13% compared with 25% +/- 4% for the control group (P < .01). An inverse relationship was seen between the FEV1 and the time on supplemental oxygen (r = -0.84, P < .0001), with 3 of the 4 children whose FEV1 was < 50% requiring oxygen for more than 900 days. Those with the greatest degree of airflow limitation and gas trapping had the greatest abnormalities in both shape and position of the pressure volume curves of the lung. CONCLUSION Severe BPD may result in moderate to severe long-term abnormalities in pulmonary function tests.

Sleep-disordered breathing in children with myelomeningocele

BACKGROUND Although patients with myelomeningocele and the Chiari II malformation are known to have sleep apnea and respiratory control deficits, the prevalence, types, severities, and associations of sleep-disordered breathing (SDB) have not been adequately defined. METHODS A cross-sectional study of our myelomeningocele clinic population was undertaken to correlate polysomnographic results with historical data and findings from magnetic resonance imaging of the Chiari malformation, pulmonary function results, and nocturnal pulse oximetry. RESULTS A questionnaire survey of symptoms was available for 107 of 109 children (98% of the clinic population), and 83 patients agreed to undergo overnight polysomnography. Breathing during sleep was classified as normal in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately/severely abnormal in 17 cases (20%). Among the 17 patients with moderately/severely abnormal SDB, 12 patients had predominantly central apneas and 5 had predominantly obstructive apnea. Patients with a thoracic or thoracolumbar myelomeningocele, those who had previously had a posterior fossa decompression operation, those with more severe brain-stem malformations, and those with pulmonary function abnormalities were more likely to have moderately/severely abnormal SDB, relative risks (95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively. Failure of obstructive SDB to resolve after adenotonsillectomy in four patients suggested abnormal control of pharyngeal airway patency during sleep. Nocturnal pulse oximetry accurately predicted moderately/severely abnormal SDB with a sensitivity of 100% and a specificity of 67%. CONCLUSIONS The pathogenesis of SDB in patients with myelomeningocele involves the functional level of the spinal lesions, congenital and acquired brainstem abnormalities, pulmonary function abnormalities, disorders of upper airway maintenance, and sleep state. Polysomnography and nocturnal pulse oximetry should be performed in high-risk patients to detect and classify SDB.

Randomized controlled trial of ipratropium bromide and frequent low doses of salbutamol in the management of mild and moderate acute pediatric asthma

OBJECTIVES To compare the effectiveness and safety of alternative nebulized drug protocols in children with mild or moderate asthma exacerbations. METHODS We conducted a blinded, randomized, controlled trial with a 2 x 2 factorial design. Two interventions, nebulized salbutamol in frequent low doses (0.075 mg/kg every 30 minutes) and the addition of ipratropium bromide (250 micrograms), were compared with salbutamol in hourly high doses (0.15 mg/kg every 60 minutes) in children with mild or moderate acute asthma. The primary end point was the improvement in respiratory resistance. Secondary end points included oxygen saturation, corticosteroid use, patient disposition, and relapse status. RESULTS A total of 298 participants aged 3 to 17 years were studied, and 15% were admitted to the hospital; 14% of the children had relapses. No increased bronchodilation was associated with frequent low doses versus hourly high doses of salbutamol (RR = 0.9 [95% confidence interval 0.7, 1.3]) or the addition of ipratropium bromide versus placebo (RR = 1.0 [0.8, 1.3]). No group differences were observed in secondary end points. Salbutamol in frequent low doses was associated with increased vomiting (RR = 2.5 [1.1, 6.0]). CONCLUSION Our results do not support the use of frequent low doses of nebulized salbutamol or the addition of ipratropium bromide compared with hourly high doses of salbutamol in children with mild or moderate asthma.

The Asthma Quiz for Kidz: A Validated Tool to Appreciate the Level of Asthma Control in Children

BACKGROUND There is an urgent need to bridge the large gap between optimal and observed asthma control among Canadian children. OBJECTIVES To adapt the criteria of asthma control proposed in the 1999 Asthma Consensus Statement for children and validate the proposed cut-offs in children with asthma. METHODS Six clinical criteria of asthma control were phrased as questions and response options, and pretested for clarity. A cross-sectional study was conducted in children one to 17 years of age presenting to the hospitals asthma clinics. Children nine years of age or older and their parents were asked to complete The Asthma Quiz for Kidz separately, and then together, before the medical visit. Parents of younger children completed the questionnaire with their child. Physicians were not informed of the results of the quiz. RESULTS The mean age of the 343 participants was 8.0+/-4.4 (SD) years with a mean baseline forced expiratory volume in 1 s of 96+/-15% of predicted values. Asthma severity was rated as mild (67%), moderate (29%) or severe (4%). Overall, 57% of subjects endorsed at least two of the six criteria of poor control. The median (interquartile range) Asthma Quiz score was significantly higher when the physicians assessment of asthma control was poor than when the physicians assessment of asthma control was good (3 [1, 5] versus 1 [0, 2], P<0.001), but it did not correlate with the spirometry. A score of at least 2 out of 6 had 73% sensitivity and 59% specificity for identifying poor control. INTERPRETATION The Asthma Quiz score provides complementary information to, but does not replace, lung function testing. A score of 2 or more out of 6 suggests poor asthma control and should prompt patients to consult their physician for reassessment.

High physician adherence to phenotype-specific asthma guidelines, but large variability in phenotype assessment in children

Abstract Background: The implementation of international pediatric asthma guidelines hinges on the distinction between intermittent and persistent phenotypes and the prescription of recommended phenotype-specific pharmacotherapy. Objectives: To ascertain key factors associated with specialist-confirmed phenotype and document physicians’ adherence to practice recommendations in an academic pediatric asthma center. Design/methods: Using electronic health records, we identified a cohort of children aged 1–17 years who presented to a tertiary-care asthma center between 2002 and 2007 and received a diagnosis of asthma from a pediatric specialist. Outcomes included: determinants of phenotypes and conformity with phenotype-specific treatment recommendations. Results: Of the 3490 eligible children (11,119 visits), most (47%) were preschoolers, 35% were 6–11 years and 18%, 13–17 years. Of children with confirmed asthma, 59% were classified on presentation as having intermittent, 41% as persistent, asthma. The within-patient phenotype varied over time with a consistency index of 0.76 (best = 1); the latter was significantly lower in preschoolers than older children (p < 0.0001). The persistent phenotype was highly physician-dependent; it was also positively associated with child’s age, asthma severity, multiple triggers, calendar year, and duration of follow-up. Compared to 33% of children with intermittent asthma, 82% of those with persistent asthma were prescribed a maintenance controller, most as monotherapy; combination therapy was usually prescribed after a trial of monotherapy. Conclusion: Pediatric asthma specialists were highly adherent to phenotype-specific pharmacotherapy. However, even in an academic center, the notable degree of intra-patient and between-physician variation in phenotype, particularly in preschoolers, was an important impediment to prescribing a maintenance controller. The findings underline the importance of developing validated and standardized means of assessing phenotypes, applicable to the whole pediatric age spectrum.