Diagnosing autism: Contemporaneous surveys of parent needs and paediatric practice.

AIM: Concurrence between parents' information needs and clinicians' practice when diagnosing autism is unknown but may influence families' uptake of management and adjustment. We aimed to compare parents' experience and preferences with paediatrician report of (i) diagnosis delivery and (ii) information given at diagnosis and identify types and usefulness of resources accessed by families post-diagnosis. METHODS: The design used for the study are parent and paediatrician surveys. Participants are parents of children aged 1.5-18 years, diagnosed with autism between 01 January 2010 and 30 September 2012 and their paediatricians who are members of the Australian Paediatric Research Network. Study-designed quantitative and qualitative questions about diagnosis delivery and information given at diagnosis (written and spoken vs. neither) and parent perceived importance and harms of information accessed post-diagnosis. RESULTS: Paediatricians (53/198 (27%)) identified 1127 eligible families, of whom 404 (36%) participated. Parents were more likely to report receiving adequate time to discuss diagnosis than paediatricians (71 vs. 51%). Parents (98%) rated information about accessing allied health professionals and the meaning of diagnosis as most important, yet paediatricians offered written or spoken information about each infrequently (allied health: 22%; diagnosis: 42%). Post-diagnosis, allied health was the most important source of information (83%). Harmful resources conveyed helplessness or non-evidenced-based therapies, but few parents (14%) reported this. CONCLUSIONS: Parents want more information than can be conveyed in a single diagnostic consultation. Developing a tailored 'autism action plan' with written materials could improve parents' understanding of and satisfaction with children's autism diagnoses.

Diagnosing autism: Australian paediatric research network surveys.

AIM: Autism spectrum disorder (ASD) is a neurodevelopmental disorder with reported prevalence of more than 1/100. In Australia, paediatricians are often involved in diagnosing ASD and providing long-term management. However, it is not known how paediatricians diagnose ASD. This study aimed to investigate whether the way Australian paediatricians diagnose ASD is in line with current recommendations. METHODS: Members of the Australian Paediatric Research Network were invited to answer questions about their ASD diagnostic practice in a multi-topic survey and also as part of a study about parents needs around the time of a diagnosis of ASD. RESULTS: The majority of the 124 paediatricians who responded to the multi-topic survey and most who responded to the parent needs survey reported taking more than one session to make a diagnosis of ASD. Most paediatricians included information from preschool, child care or school when making a diagnosis, and over half included information from speech pathology or psychology colleagues more than 50% of the time. The main reasons for not including assessment information in the diagnostic process were service barriers such as no regular service available or long waiting lists. More than 70% reported ordering audiology and genetic tests more than half of the time. CONCLUSION: Not all paediatricians are following current recommendations for diagnosing ASD more than 50% of the time. While there are good reasons why current diagnostic approaches may fall short of expected standards, these need to be overcome to ensure diagnostic validity and optimal services for all children and their families.

Chocolate frogs do not increase completion of parent survey: randomised study.

Four months into a year-long, national survey assessing parents' experiences of a child's diagnosis of autism spectrum disorder, our response fraction was only 23%. We aimed to determine whether including a chocolate incentive in the postal survey would increase the response fraction. Families enrolled between 15 March and 25 May 2012 were randomised to receive a chocolate frog versus no chocolate frog. Both groups received a written reminder and replacement survey 2 weeks after the survey was posted and up to two telephone reminders thereafter. We analysed the effect of the incentive using χ(2) tests for the categorical response variable and t-tests for the continuous reminder and length of response variables at the end of (i) randomisation and (ii) the study (1 November 2012). A total of 137 families were randomised in the 6-week period. Parents who received an incentive were more likely to return a completed survey in the 6 weeks than those who did not (21% vs. 6%, P = 0.009). This effect faded by the end of the study (53% vs. 42%, P = 0.4). There were no differences between groups at either follow-up in the number of reminders that parents received or the number of days it took parents to return the survey. Including a chocolate-based incentive does not significantly increase response rate in a postal survey over and above standard reminder techniques like posting follow-up survey packs or phoning families.

Growth of lung parenchyma in infants and toddlers with chronic lung disease of infancy.

RATIONALE: The clinical pathology describing infants with chronic lung disease of infancy (CLDI) has been limited and obtained primarily from infants with severe lung disease, who either died or required lung biopsy. As lung tissue from clinically stable outpatients is not available, physiological measurements offer the potential to increase our understanding of the pulmonary pathophysiology of this disease. OBJECTIVES: We hypothesized that if premature birth and the development of CLDI result in disruption of alveolar development, then infants and toddlers with CLDI would have a lower pulmonary diffusing capacity relative to their alveolar volume compared with full-term control subjects. METHODS: We measured pulmonary diffusing capacity and alveolar volume, using a single breath-hold maneuver at elevated lung volume. Subjects with chronic lung disease of infancy (23-29 wk of gestation; n = 39) were compared with full-term control subjects (n = 61) at corrected ages of 11.6 (4.8-17.0) and 13.6 (3.2-33) months, respectively. MEASUREMENTS AND MAIN RESULTS: Alveolar volume and pulmonary diffusing capacity increased with increasing body length for both groups. After adjusting for body length, subjects with CLDI had significantly lower pulmonary diffusing capacity (2.88 vs. 3.23 ml/min/mm Hg; P = 0.0004), but no difference in volume (545 vs. 555 ml; P = 0.58). CONCLUSIONS: Infants and toddlers with CLDI have decreased pulmonary diffusing capacity, but normal alveolar volume. These physiological findings are consistent with the morphometric data obtained from subjects with severe lung disease, which suggests an impairment of alveolar development after very premature birth.

Growth of the lung parenchyma early in life.

RATIONALE: Early in life, lung growth can occur by alveolarization, an increase in the number of alveoli, as well as expansion. We hypothesized that if lung growth early in life occurred primarily by alveolarization, then the ratio of pulmonary diffusion capacity of carbon monoxide (Dl(CO)) to alveolar volume (V(A)) would remain constant; however, if lung growth occurred primarily by alveolar expansion, then Dl(CO)/V(A) would decline with increasing age, as observed in older children and adolescents. OBJECTIVES: To evaluate the relationship between alveolar volume and pulmonary diffusion capacity early in life. METHODS: In 50 sleeping infants and toddlers, with equal number of males and females between the ages of 3 and 23 months, we measured Dl(CO) and V(A) using single breath-hold maneuvers at elevated lung volumes. MEASUREMENTS AND MAIN RESULTS: Dl(CO) and V(A) increased with increasing age and body length. Males had higher Dl(CO) and V(A) when adjusted for age, but not when adjusted for length. Dl(CO) increased with V(A); there was no gender difference when Dl(CO) was adjusted for V(A). The ratio of Dl(CO)/V(A) remained constant with age and body length. CONCLUSIONS: Our results suggest that surface area for diffusion increases proportionally with alveolar volume in the first 2 years of life. Larger Dl(CO) and V(A) for males than females when adjusted for age, but not when adjusted for length, is primarily related to greater body length in boys. The constant ratio for Dl(CO)/V(A) in infants and toddlers is consistent with lung growth in this age occurring primarily by the addition of alveoli rather than the expansion of alveoli.

Expired nitric oxide and airway reactivity in infants at risk for asthma.

BACKGROUND: Family histories of atopy, as well as histories of atopic dermatitis and food allergy, are important risk factors for an infant to have asthma. Although atopic sensitization appears to contribute to the development of asthma, it is unclear when the airways become involved with the atopic process and whether airway function relates to the atopic characteristics of the infant. OBJECTIVE: We sought to evaluate whether atopic infants without prior episodes of wheezing have increased expired nitric oxide (eNO) levels and heightened airway reactivity. METHODS: Infants with eczema were recruited, and atopic status was defined by specific IgE levels to foods or aeroallergens and total IgE levels. eNO, forced expiratory flow at 75% exhaled volume (FEF(75)), and airway reactivity to inhaled methacholine were measured in sedated infants. Airway reactivity was quantified by using the provocative concentration to decrease FEF(75) by 30%. RESULTS: Median age for the 114 infants evaluated was 10.7 months (range, 2.6-19.1 months). Infants sensitized to egg or milk compared with infants sensitized to neither egg nor milk had lower flows (FEF(75): 336 vs 285 mL/s, P < .003) and lower lnPC(30) (mg/mL) provocative concentrations to decrease FEF(75) by 30% (-0.6 vs -1.2, P < .02) but no difference in eNO levels. Infants with total serum IgE levels of greater than 20 IU/mL had higher eNO levels compared with infants with IgE levels of 20 IU/mL or less (14.6 vs 11.2 ppb, P < .023) but no difference in forced flows or airway reactivity. CONCLUSIONS: Our findings suggest that atopic characteristics of the infant might be important determinants of the airway physiology of forced expiratory flows, airway reactivity, and eNO.

Measurement of single breath-hold carbon monoxide diffusing capacity in healthy infants and toddlers.

We describe a method for measuring carbon monoxide diffusing capacity (DL(CO)) and alveolar volume (V(A)) in sleeping infants, using a single 4-sec breath-hold technique. The breath-hold maneuver is obtained by inducing a respiratory pause of the respiratory system. Several inflations of the respiratory system with room air to a lung volume with an airway pressure of 30 cmH2O (V30) inhibit inspiratory effort. The respiratory system is then inflated with a test gas containing helium and a stable isotope of carbon monoxide (C18O), and a respiratory pause is maintained for 4 sec and followed by passive expiration to functional residual capacity. Concentrations of helium and C18O are continuously measured with a mass spectrometer. Twelve healthy infants between 6-22 months of age were evaluated. For 9 of 12 subjects, duplicate measurements of alveolar volume at 30 cmH2O (V(A30)) and DL(CO) were within 10%, which are the recommendations for older children and adults. Among these 9 subjects, values of V(A30) and DL(CO) increased with increasing body length (r2 = 0.82 and 0.79, respectively). The remaining 3 subjects had two values within 10-15%. Measurement of V(A) and DL(CO) with the single breath-hold technique at an elevated lung volume offers the potential to assess growth and development of the lung parenchyma early in life.

Lung growth in infants and toddlers assessed by multi-slice computed tomography.

RATIONALE AND OBJECTIVES: Postnatal lung growth and development have primarily been evaluated from a very limited number of autopsied lungs, but it remains unclear whether alveolarization of the lung is complete during infancy and whether the conducting airways grow proportionately. The purpose of this study was to evaluate lung growth and development in vivo in infants and toddlers using multislice computed tomography. MATERIALS AND METHODS: Thirty-eight subjects (14 male, 24 female) aged 17 to 142 weeks underwent low-dose volumetric high-resolution computed tomographic imaging at an inflation pressure of 20 cm H(2)O during an induced respiratory pause. Lung volume and weight were determined, as well as airway dimensions (inner and outer area and wall area) for the trachea and the next three to four generations. RESULTS: Lung volume, air volume, and tissue volume increased linearly with body length. The air and tissue components of the lung parenchyma increased at a constant rate with each other. In addition, airway caliber decreased with increasing generation from the trachea into each lobe. Airway caliber was also correlated with body length; however, there was no interaction effect between airway generation and body length on transformed airway size. CONCLUSIONS: In vivo assessment suggests that the growth of the lung parenchyma in infants and toddlers occurred with a constant relationship between air volume and lung tissue, which is consistent with lung growth occurring primarily by the addition of alveoli rather than the expansion of alveoli. In addition, the central conducting airways grow proportionately in infants and toddlers. This information may be important for evaluating subjects with arrested lung development.

Parental smoking and airway reactivity in healthy infants.

Parental tobacco smoking is associated with lower airway function and an increased incidence of wheezy respiratory illnesses in infants. We evaluated in 76 healthy infants whether exposure to parental tobacco smoking was associated with airway hyperreactivity, which could contribute to lower airway function and the increased wheezy illnesses. Airway function was measured using the raised-volume rapid thoracic compression technique, and airway reactivity was assessed by methacholine challenge (0.015-10 mg/ml), which was stopped for a more than 30% decrease in forced expiratory flow (FEF)(75) or the final dose with a less than 30% decrease. Parental tobacco smoking was associated with lower baseline airway function (FEF(50), 600 vs. 676 ml/second, p < 0.04; FEF(25-75), 531 vs. 597 ml/second, p < 0.05). Infants exposed to tobacco smoking were approximately half as likely to develop a more than 30% decline in FEF(75) at any given methacholine dose (hazard ratio = 0.4, p = 0.001). In addition, a history of asthma in an extended family member increased the likelihood that an infant would develop a more than 30% decline in FEF(75) (hazard ratio = 1.7, p = 0.04). We conclude that exposure to parental smoking is associated with lower airway function but not increased airway reactivity; however, family history of asthma is associated with heightened airway reactivity.

High-resolution computed tomography imaging of airway disease in infants with cystic fibrosis.

RATIONALE: The development of early lung disease in patients with cystic fibrosis (CF) remains poorly defined. OBJECTIVE: Determine whether asymptomatic infants with CF have evidence for changes in airway structure when assessed by high-resolution computed tomography, and whether airway structure correlates with airway function in this age group. METHODS: Thirteen infants with CF (8-33 mo) and 13 control infants (7-25 mo) were evaluated. Airway wall and lumen areas were measured from three 1-mm-thick cross-sectional images obtained from upper, middle, and lower lobes during a respiratory pause with the lungs inflated to an airway pressure of 20 cm H2O. Lung tissue density was measured from images obtained during a respiratory pause at FRC. Forced expiratory flows were measured by the rapid thoracic compression technique in 11 infants with CF. RESULTS: Airway wall area increased more per unit increase in airway size, whereas airway lumen area increased less per unit increase in airway size in the CF than in the control group. Among infants with CF, a greater ratio of wall to lumen area correlated with lower airway function. In addition, lung density at relaxed (passive) FRC was lower for infants with CF than for control infants (0.38 vs. 0.43 g/ml; p < 0.02). CONCLUSIONS: Our results indicate that infants with CF have thickened airway walls, narrowed airway lumens, and air trapping, when assessed by high-resolution computed tomography, and measurements of airway structure correlated with airway function.