Anthony Mansell

Relationship of asthma severity and psychological problems in children.

OBJECTIVE To determine whether physiological severity of asthma is associated with increased psychological symptoms in children. METHOD Participants were 337 children, aged 7 to 19 years (mean 11.9, SE 0.13), and a parent of each child. Childrens asthma severity was rated by experienced pediatric asthma specialists using current guidelines from the National Heart, Lung, and Blood Institute. Children filled out the Childrens Manifest Anxiety Scale and the Weinberger Adjustment Inventory. Parents reported on their childs medical history, completed the Child Behavior Checklist (CBCL) about their child, and completed the Pennebaker Inventory of Linguid Languidness as a measure of their own physical symptoms. RESULTS Child-rated anxiety symptoms were unrelated to asthma severity or to markers of asthma functional morbidity. Parental ratings of internalizing symptoms in their children were related to severity. Parent physical symptoms explained 10.2% of the variance in CBCL Internalizing symptoms, and asthma severity added an additional 6.7% to the variance. CONCLUSIONS Asthma severity may be a more salient stressor to parents, who in turn report higher levels of child internalizing symptoms for children with severe asthma, than to children themselves. Contrary to prior hypotheses, children with severe asthma did not rate themselves as having higher levels of anxiety than those with mild or moderate asthma or than standardized norms.

Cardiorespiratory Response to Exercise after the Fontan Procedure for Tricuspid Atresia

ABSTRACT: Noninvasive exercise testing was used to assess gas exchange in 13 patients age 6–25 yr who had undergone Fontan procedures for tricuspid atresia, five of whom had preexisting Glenn shunts. The results were compared to 28 age- and sex-matched controls. Oxygen saturation was measured by ear oximetry at rest and after exercise. Ventilation oxygen consumption (VO2), carbon dioxide production (VCO2), and heart rate were measured during progressive exercise. The ventilatory equivalents for oxygen (VE/VO2) and carbon dioxide (VE/VCO2), mixed expired pCO2 (PECO2) end-tidal pCO2 (PETCO2), and dead space to tidal volume ratio (VD/VT) were determined during steady state exercise on a cycle ergometer. Heart rate was higher for VO2 by 15% (p < 0.02) and ventilation was higher for both VO2 (by 37%, p < 0.001) and VCO2 (by 27%, p < 0.002) in the patients than the controls. Mean VE/VO2 was 35.4 ± 7.8 (SD) compared to 25.8 ± 3.1 (p < 0.001) and mean VE/VCO2 was 41.7 ± 9.0 compared to 31.6 ± 4.3 (p < 0.001). Mean PECO2 was 21.4 ± 4.4 torr with controls at 27.9 ± 3.8 (p < 0.001) and mean PETCO2 was 33.0 ± 5.3 torr compared to 40.0 ± 3.3 (p < 0.001). The patients had a mean oxygen saturation of 92 ± 5% at rest and abnormal saturation after exercise (87 ± 9, p < 0.005). There were no differences in VE/VO2, VE/VCO2, PECO2, PETCO2, % of Hb saturated with oxygen before and after exercise, or VD/VT ratios between the five patients who had also undergone the Glenn operation and those who had not. Two patients who had right atrium to right pulmonary artery anastomoses demonstrated higher (VE/VO2 and VE/VCO2 ratios, lower end-tidal and mixed expired pCO2, and lower % of Hb saturated with oxygen before and after exercise than the patients with right atrium to right ventricle anastomoses. Patients with tricuspid atresia who have undergone the Fontan operation show high heart rate for oxygen consumption, high ventilation for O2 consumption and CO2 production, low expired CO2 concentrations, and oxygen desaturation during exercise. The results indicate elevated physiological dead space and ventilation perfusion mismatch consistent with maldistribution of pulmonary blood flow in patients with Fontan physiology who have had either a right atrium to pulmonary artery or right atrium to right ventricle connection with or without a previous Glenn shunt. Longer follow-up of these patients will be necessary to determine the late clinical implications of these findings.

The effect of transfusion on lung capacity, diffusing capacity, and arterial oxygen saturation in patients with thalassemia major.

ABSTRACT. Our previous cross-sectional study of patients with thalassemia major suggested progressive lung changes characterized by low total lung capacity, hypoxemia, and elevated transfer factor for carbon monoxide. We reevaluated nine of the patients for three reasons: 1) to determine the relationship of the previous findings to the immediate effects of blood transfusion; 2) to assess the longitudinal progression of the lung changes; and 3) to evaluate the effect of splenectomy on lung volume changes in these patients, all of whom underwent splenectomy in the interval between the two studies. We found that during the 5- to 6-yr period between studies total lung capacity had decreased significantly (p<0.05) from a mean 86% predicted to a mean 79% predicted. However, vital capacity increased significantly (p<0.05) from a mean 81% predicted to 88% with no significant change in functional residual capacity. There was no significant immediate effect of transfusion on total lung capacity, vital capacity, or functional residual capacity. However, the diffusion constant for carbon monoxide increased significantly (p<0.005) immediately following transfusion and there was a positive correlation between the increase and the amount of blood transfused (r=0.74, p<0.05). Arterial oxygen saturation was below 95% in five of eight patients and increased significantly with transfusion (p<0.05). We conclude: 1) thalassemia major and/or its treatment is associated with hypoxemia and a progressive reduction in total lung capacity. 2) Despite the progressive reduction in total lung capacity, splenectomy in patients with thalassemia major increases expiratory reserve volume and thereby increases vital capacity. 3) The previous finding of elevated KCO carbon monoxide is explained quantitatively as a transient effect caused by blood transfusion. 4) Transfusion in patients with thalassemia major without overt signs of cardiac failure is usually associated with a transient increase in arterial oxygen saturation.

Frequency and Correlates of Overweight Status in Adolescent Asthma

Background: Debate exists within the literature concerning whether asthma and obesity are linked as comorbid conditions. Further study is required to understand the relationship between asthma and overweight status, and developmental considerations are an important priority area. Objective: The present study addressed gaps in the existing literature by comparing rates of overweight status among a matched sample of adolescents with and without asthma and by examining correlates of overweight status among youth with asthma. Methods: Rates and correlates of overweight status were compared among a matched cohort of 103 adolescents with asthma, 75 adolescents with asthma characterized by history of a severe acute event, and 92 normal controls. Results: Significantly higher rates of overweight status were found among the asthma groups compared to the control group and to population estimates. Significant correlates for overweight status included younger age and earlier age at asthma diagnosis, suggesting that receiving an asthma diagnoses in early childhood may increase the propensity for weight gain. Conclusion: Asthma and obesity are problematic comorbid conditions, and specialized obesity prevention programs may be particularly necessary at the onset of a new asthma diagnosis. Clinical Implications: Identifying and addressing the factors that may contribute to the potential for obesity among youth with asthma are key research and clinical practice priorities.

Thresholds of resistive load detection in children with asthma

Threshold detection of added resistive loads was studied in asthmatic children and compared to data previously obtained in a group of healthy children. The relationships between possible psychological predictors of perceptual ability, the perceptual threshold, and functional morbidity variables were also investigated. Our subjects were 103 children (mean age, 10.9 years) with asthma who completed two laboratory protocols in which they were asked to distinguish breaths with varying degrees of added resistance from unloaded breaths. Using two different computer‐driven protocols, resistances were presented as percentages of each childs intrinsic respiratory system resistance (Rrs). Cognitive ability was assessed through subtests of the Wechsler Intelligence Scale for Children, 3rd edition (WISC‐III), and functional morbidity was quantified through a combination of school absences, emergency medical visits, and days hospitalized.

Resistive-load detection in healthy school-aged children.

The ability to detect changes in respiratory resistance, which may be important in acute and chronic adaptations to airways obstruction, has not been measured previously in children. Two methods were used to measure the resistive‐load detection thresholds (the added resistance that produced a “just noticeable difference” in perception) in a group of 38 healthy children and adolescents aged 7–16 years. Total respiratory system resistance (Rrs), as measured by forced oscillation, was used as an index of each childs intrinsic baseline (pre‐test) resistance. To determine thresholds, a computer program added various percentages of baseline resistance according to response (first method) and then in random order (second method). Thresholds by at least one of the two methods were detectable in 32 of the children (84%), and failure to detect a threshold was less common in older than in young children. Thresholds obtained by each method were significantly related to one another (r = 0.54, P < 0.05). Baseline resistance accounted for a marginally significant proportion of the variation in thresholds as assessed by the tracking method (R2 = 0.12, P < 0.10) and a large proportion of the variation in thresholds as assessed by the random method (R2 = 0.66, P < 0.0001). Thresholds expressed in terms of percent of baseline resistance were found to have mean values of 100.4–105.0%, regardless of gender or age. Results from a comparison group of adults (n = 10) indicated lower threshold by both procedures (mean values, 71.90–76.50%). We conclude that perceptual thresholds for added resistive loads are determined, in part, by growth‐related changes in intrinsic resistance. Pediatr Pulmonol. 1996; 22:357–363.

Unilateral Diaphragmatic Paralysis Inhibits Postnatal Lung Growth in the Piglet

ABSTRACT: To test the hypothesis that regional growth of lung parenchyma depends on regional distending pressure, left cervical phrenectomy was done in ten 2-month-old piglets. The unilateral diaphragmatic paralysis reduced mean transpulmonary pressure in the left hemithorax from 5.5 ± 1.0 (x ± SD) to 2.5 ± 1.2 cm H2O (p < 0.01, n = 5). When five of the piglets were killed 48 h later, wet lung weight, total protein content, and nucleic acid content did not differ from values in the five sham operated controls. The five remaining phrenectomized piglets were compared to their five sham-operated controls 7 days after surgery. Wet weight of the left lung was reduced by 29% (p < 0.01) and DNA content was reduced by 18% (p < 0.05). Wet weight of the right lung, contralateral to the paralyzed hemidiaphragm, was reduced by 11% (p < 0.05). At this time, body weight, bilateral transpulmonary pressure, and ratios of total protein/DNA and RNA/DNA in lung tissue did not differ from the sham-operated controls. These results suggest that regional growth of lung parenchyma by cell proliferation adjusted to changes in regional transpulmonary pressure caused by the unilateral phrenectomy.

Improved Methodology for Threshold Detection Studies in Asthmatic Children

Abstract This paper reports the differences between two methodologies for threshold detection of added resistive loads in children and adolescents. The first-generation apparatus utilized a series of laminar flow screens to present various total resistances, while in the second generation the apparatus utilized a servo-controlled cone that occluded an aperture to varying degrees. Protocol modifications in the second generation methodology included forced choice, attentional enhancements, and larger increments of added resistance. Two studies conducted 2 years apart provided data on the first and second generations of methodology. All participants in Study 1 (N = 33) and Study 2 (N = 33) were children with asthma. Subjects were matched for both age and asthma severity. Results showed the methodologic improvements in the second generation to be significant. Tracking and random thresholds were achieved by 85% and 82% of the subjects in Study 2 compared to 76% and 42% in Study 1, respectively. The correlation...

1795 DISTENDING PRESSURE DETERMINES POSTNATAL GROWTH OF LUNG PARENCHYMA IN THE CAT

To test the hypothesis that distending pressure produced by the respiratory muscles determines postnatal growth of lung parenchyma, we studied unilateral diaphragmatic paralysis in kittens. Twelve 10–12 week old kittens underwent left thoracotomy. In 6, unilateral phrenectomy was done via the thoracotomy; the other 6 served as controls. Five to 7 weeks later, body weight had increased by 49% in the phrenectomized group and by 47% in the controls (NS). However functional residual capacity by helium dilution under ketamine hydrochloride anaesthesia was lower in the phrenectomized group (35 ± 4 ml versus 58 ± 9 ml in the controls, P<.001). As measured by bilateral pleural balloons, mean transpulmonary pressure ipsilateral to the phrenectomy was lower than mean transpulmonary pressure contralateral to the phrenectomy (P<.05). In postmortem studies, growth of contralateral lungs relative to ipsilateral lungs was greater in the phrenectomized animals than in the controls, as shown by ratios of contralateral/ipsilateral wet lung weight (1.44 versus 1.34, P< .005), maximum inflation volume (1.53 versus 1.33, P< .005) and total protein content (1.45 versus 1.26, P<.002). Ratios of total protein/DNA and ENA/DNA were unchanged. We conclude that postnatal growth of lung parenchyma by cell proliferation in the cat depends on pulmonary distending pressure.