bluuebunny/crossref_metadata_2025 huggingface dataset:
Monocytes in cystic fibrosis: Responsiveness to microbial stimuli
Authors: Thomassen Mary Jane , Barna Barbara P. , Farmer Mark O. , Doershuk Carl F. , Stern Robert C.
Published: March 2007

Peripheral blood monocytes were obtained from 19 patients with cystic fibrosis (CF) and age‐matched paired normal individuals. The oxidative metabolic response of these cells was measured by superoxide anion production before and after stimulation with Salmonella typhimurium or Pseudomonas aeruginosa lipopolysaccharide (LPS). CF monocytes showed slightly greater spontaneous superoxide anion production (14.1 ± 2.1 SEM nanomoles superoxide anion/ 106 monocytes/180 min; n = 12) than normal monocytes (9.5 ± 1.4; n = 12), P = 0.009. No differences between CF and normals were found in LPS‐stimulated superoxide anion production (CF = 33.5 ± 4.6, n = 13; normal = 33.8 ± 4.2, n = 13). Furthermore, CF monocytes responded to both P. aeruginosa and S. typhimurium LPS stimulation as well as to recombinant interferon‐gamma. Superoxide anion production of CF monocytes was comparable in autologous serum and in normal serum, and responses of patients colonized with P. aeruginosa and P. cepacia did not differ. We conclude that CF monocytes have a slightly increased metabolic level and, despite chronic infection, are capable of a further response to exogenous microbial stimuli. Pediatr Pulmonol 1990; 8:178‐181.
Effect of spontaneous and mechanical breathing on dynamic lung mechanics in hyaline membrane disease
Authors: Mammel Mark C. , Fisher Joel B. , Bing Dennis R. , Gatto Catherine W. , Boros Stephen J.
Published: March 2007

We measured then compared the dynamic lung mechanics of spontaneous breaths and mechanical breaths in 9 mechanically ventilated neonates with hyaline membrane disease. All were receiving intermittent mandatory ventilation. All breathed spontaneously between ventilator breaths. Tidal volume, transpulmonary pressure, dynamic lung compliance, airways resistance, and peak inspiratory and peak expiratory gas flows were determined for both the mechanical and the spontaneous breaths. The mechanical breaths consistently had larger tidal volumes, higher transpulmonary pressures, higher airway resistance, and lower lung compliance values (P < 0.05). Peak inspiratory and expiratory gas flows were also higher (P < 0.01) during mechanical breathing. The spontaneous breaths generated by patients and the mechanical breaths generated by mechanical ventilators are different. The lung mechanics measurements of these two different types of breathing should be collected, analyzed, and reported separately. Pediatr Pulmonol 1990; 8:222‐225.
Neonatal gastric intubation: Differential respiratory effects between nasogastric and orogastric tubes
Authors: Greenspan Jay S. , Wolfson Marla R. , Holt William J. , Shaffer Thomas H.
Published: March 2007

The acute effects of nasogastric (NG) and orogastric (OG) tube placement on pulmonary function of neonates was assessed as a function of infant weight. Lung function was obtained on 14 healthy infants weighing less than 2 kg and 10 infants heavier than 2 kg with an NG and an OG tube in place. Additionally, 15 infants were studied for a third time without gastric intubation. Lung function was determined with an esophageal balloon and by pneumotachography (PeDS™) via the least mean square analysis technique. Neither the below‐2 kg infants nor the above‐2 kg infants had apparent clinical compromise with NG and OG tube placement. Infants weighing less than 2 kg, however, demonstrated diminished minute ventilation and respiratory rate and had increased pulmonary resistance, resistive work of breathing, and peak transpulmonary pressure change with NG tube, as compared to OG tube, placement. The above‐2 kg infants demonstrated no change in pulmonary function with NG vs. OG tube placement. These data indicate that small neonates demonstrate significant pulmonary compromise with NG placement that may not be clinically apparent. Pediatr Pulmonol 1990; 8:254‐258.
Methodological aspects of flow‐volume studies in infants
Authors: Turner Debra J. , Morgan Susan E. G. , Landau Louis I. , Lesouëf Peter N.
Published: March 2007

Although valuable information is being obtained using new techniques to assess infant respiratory mechanics, there have been several concerns about the methodology. These relate to the possibility that chloral hydrate may affect flow‐volume measurements by altering upper airway caliber. There is also the possibility that physiological changes may be induced by inhalation of non‐pharmacologic and pharmacologic nebulized solutions. The aim of this study was to investigate these phenomena in a group of normal infants. Thoracic gas volume was determined and respiratory mechanics measured using the passive and forced expiratory flow‐volume techniques. Respiratory function was assessed in infants before and after 1) sleep was induced by administration of chloral hydrate (n = 10, mean age, 21 weeks); 2) inhalation of nebulized saline (n = 10, mean age, 19 weeks); 3) inhalation of nebulized salbutamol (n = 7, mean age, 22 weeks). A fall in tidal volume was found following administration of chloral hydrate but no significant change was seen in any other respiratory parameter. In addition, no change was seen in any parameter post‐saline or salbutamol nebulization. This study provides data which support several basic assumptions made about the infant flow‐volume techniques and should provide useful background information for future studies using these techniques. Pediatr Pulmonol 1990; 8:289‐293.
Glucocorticoid receptor concentrations in human lung at different growth stages
Authors: Labbe A. , Grizard G. , Dechelotte P. , Raynaud E. J.
Published: March 2007

We measured glucocorticoid receptor concentrations in human lung at different stages of alveolar growth. Lung tissue was obtained from 9 surgically aborted or stillborn fetuses of 15 to 28 weeks gestational age, and from 6 infants and children, aged 2 months to 9 years, after lobar resection or at autopsy. Samples were taken from macroscopically healthy areas. Lung histology was performed in all cases. The receptor assay was done by establishing saturation curves for labeled dexamethasone in the absence or presence of a hundredfold excess of unlabeled dexamethasone. Total binding capacity and the dissociation constant were calculated from the saturation curves by the method of Scatchard. The receptor concentration in the fetuses was high (182 ± 88 fmol/mg prot.), irrespective of gestational age. The lowest concentration (35 fmol/mg prot.) was found in a fetus with pulmonary hypoplasia. In the infants and children the mean receptor concentration was significantly lower (14.6 ± 9.9 fmol/mg prot.); these included a case of sudden death in which the parenchymal structure was normal. Pediatr Pulmonal 1990; 9:140–145.
Effects of chest physical therapy on lung function in children recovering from acute severe asthma
Authors: Asher M. Innes , Douglas Catherine , Airy Margaret , Andrews Deborah , Trenholme Adrian
Published: March 2007

The effects of chest physical therapy in acute severe asthma in children have been studied in 38 children aged 6 to 13 years in a randomized placebo controlled trial. The study began between 6 and 24 hours after admission to hospital; 19 children received chest physical therapy (PT) and 19 children received placebo visits. Each child had 4 treatments over 2 days which were preceded by nebulized salbutamol. Lung volumes and flow rates were measured in a body plethysmograph before salbutamol and before and after either PT or placebo on the first and fourth treatments. Throughout the study standard asthma drug therapy was given. In both groups characteristics such as sex, race, age, height, weight, severity, and baseline lung function were similar. Taking into account the baseline, lung function at the end of the study was similar in both groups. Three 12 year old children in the PT group showed improvements in flows above those seen in any children in the placebo group. We conclude that chest PT, when combined with asthma drug therapy, does not improve lung function in most children in this age group with acute severe asthma. Pediatr Pulmonal 1990; 9:146–151.
Pulmonary vascular damage and the development of cor pulmonale following hyaline membrane disease
Authors: Hislop Alison A. , Haworth Sheila G.
Published: March 2007

Light microscopic morphometric techniques have been used to study the lungs in 17 infants and young children aged 2 weeks to 3.5 years who were born prematurely, developed hyaline membrane disease (HMD), and died with chronic lung disease. They were divided into three groups. In group 1 the babies died without recovering from their intitial illness at age 2–13 weeks. In group 2 they died, aged 4–15 months, having recovered from the neonatal illness. Neither group showed clinical or pathological evidence of cor pulmonale (CP). In group 3 children died aged 6 months to 3.5 years with CP. None of the 17 patients had classical fibrotic bronchopulmonary dysplasia (BPD) but all had a reduced alveolar number and an increase in bronchial smooth muscle in small airways. All three groups showed an increase in pulmonary arterial medial thickness (P < 0.001). In group 1 the appearance of the arteries suggested persistance of the fetal state. In group 2 and 3 the vessels had a more mature structure; in group 3 a marked secondary increase in muscularity was found, approaching the thickness seen in fetal life. In groups 2 and 3 muscle extended into smaller arteries than normal. Vein wall thickness was increased. The alveolar to arterial ratio was normal, the alveolar number was reduced, therefore the total number of arteries was reduced in all three groups. Thus, babies who recover from HMD may have significant vascular abnormalities in the absence of CP; conversely, CP if present, does not mean advanced obliterative pulmonary vascular disease. Thus, pulmonary vascular morphology does not correlate with the presence or absence of CP. Pediatr Pulmonal 1990; 9:152–161.
Corticosteroids do not affect the clinical or physiological status of infants with bronchiolitis
Authors: Springer Chaim , Bar‐Yishay Ephraim , Uwayyed Kamal , Avital Avraham , Vilozni Daphna , Godfrey Simon
Published: March 2007

The treatment of infants aged 1.5–11.0 months suffering from acute bronchiolitis with a combination of inhaled albuterol and systemic corticosteroids or inhaled albuterol and placebo was compared in 50 infants in a double blind study. The mean initial clinical score and the rate of improvement was similar in the two groups. The mean ± SD hospital stay was 5.0 ± 1.2 days for the steroid group and 5.2 ± 1.7 days for the placebo group. Lung function was measured in 14 infants (7 from each group) and showed evidence of increased lung volumes and severe airway obstruction in the acute stage (the mean values for the steroid group were: TGV, 31 mL/kg; SGaw, 0.104 L/s·cmH2O; V̇maxFRC, 12.9 mL/s/kg; for the placebo group: TGV, 35 mL/kg; SGaw, 0.104 L/s·cmH2O; V̇maxFRC, 8.5 mL/s/kg) which had improved 2–4 weeks later (steroid group: TGV, 25 mL/kg; SGaw, 0.168 L/s·cmH2O; V̇maxFRC, 21.6 mL/s/kg; –placebo group: TGV, 24 mL/kg, SGaw, 0.198 L/s·cmH2O, V̇maxFRC, 17.5 mL/s/kg). There were no significant differences of thoracic gas volume, specific airway conductance, and forced expiratory flow at resting lung volume between the two groups, either in the acute or convalescent stages. We conclude that corticosteroids do not change the rate of clinical improvement in acute bronchiolitis, nor do they effect lung function 2–4 weeks later. Pediatr Pulmonal 1990; 9:181–185.
Evaluation of a mainstream capnometer and end‐tidal carbon dioxide monitoring in mechanically ventilated infants
Authors: Meredith Keith S. , Monaco Frank J.
Published: March 2007

We evaluated a new lightweight capnometer with a < 1 mL deadspace neonatal airway adapter and endotracheal tube connector unit (NAC) for use in mechanically ventilated neonates. The evaluation consisted of: 1) a bench test comparison of air flow resistance between the standard endotracheal tube and connector with the new NAC (flow rates, 1.5 to 12.8 L/min); 2) a determination of the effect of NAC placement on Pa; 3) pre‐ and post‐NAC pulmonary mechanics; and 4) an analysis of paired Pet and Pa in 16 infants requiring mechanical ventilation. Paired t test of the slopes of the resistance curves was significant (P = 0.002) while analysis of variance of differential pressures was not (P = 0.29). All post‐NAC placement Pa were smaller than pre‐placement values; there were no differences in pulmonary mechanics, and Pet correlated closely with Pa (n = 132, r = 0.79) defined as Pet = 0.68 • Pa + 5.21; x̄ ± 1 SD, Pa–Pet was 4.7 ± 4.7 torr and Pet/Pa was 0.86 ± 0.14. Pediatr Pulmonal 1990; 9:254–259.
The paradox of adult respiratory distress syndrome in neonates
Authors: Pfenninger Juerg , Tschaeppeler Heinz , Wagner Bendicht Peter , Weber Jann , Zimmerman Arthur
Published: March 2007

Six full‐term newborn infants are described who suffered from severe adult respiratory distress syndrome (ARDS). The triggering event was intrauterine/perinatal asphyxia in five, and group B streptococcal (GBS) septicemia in three. All had severe respiratory distress/failure and were ventilated mechanically with high concentrations of inspired oxygen and positive end‐expiratory pressure. Radiography of the chest showed dense bilateral consolidation with air bronchograms and reduced lung volume. Persistent pulmonary hypertension (PPH) was documented in all cases. The coincidence of ARDS and PPH rendered respiratory management extremely difficult. For this reason high‐frequency ventilation was instituted in all patients in order to improve CO2 elimination and induce respiratory alkalosis. Acute complications of respiratory therapy were encountered in five patients (pneumothorax, pulmonary interstitial emphysema, pneumopericardium). Three infants died (irreversible septic shock, progressive severe hypoxemia, and sudden cardiac arrest) after 17, 80, and 175 h of life. Histologic examination of the lungs was possible in all fatal cases and revealed typical changes of acute to subacute stages of ARDS. Three infants survived, the mean time of mechanical respiratory support being 703 h. Two patients were still dependent on oxygen after 1 month of life, and all survivors had increased interstitial markings and increased lung volumes on their chest roentgenograms at this time. Pediatr Pulmonol 1991; 10:18–24.
Effectiveness and safety of small vs. large doses of enteric coated pancreatic enzymes in reducing steatorrhea in children with cystic fibrosis: A prospective randomized study
Authors: Brady Mary Sue , Rickard Karyl , Yu Pao‐Lo , Eigen Howard
Published: March 2007

Among cystic fibrosis (CF) centers, usual doses of enteric coated (EC) pancreatic enzymes vary from one to six capsules per meal based upon arbitrary criteria for stool and growth patterns. Large doses of non‐EC enzymes are associated with increased serum urate (SU) and urinary uric acid (UUA) but data are unavailable for EC enzymes. This study compared the effectiveness and safety of a relatively large dose (patient's usual dose) versus a small dose (¼ usual dose) of EC enzymes in nine nourished children with CF, regarding decreasing fecal fat and stool nitrogen losses and maintaining normal SU and UUA concentrations. A crossover study design randomly assigned large or small doses to two consecutive 7 day treatment periods within each child. Large doses of EC enzymes reduced steatorrhea and increased SU and UUA. SU was normal with both treatments and UUA was normal, i.e., 17 of 18 values were between the 10th and 95th percentiles for healthy children eating a normal diet. When fat excretion was greater than 10% with small doses of EC enzymes, large doses resulted in reduced fat excretion and normal UUA. These data suggest that large doses of EC enzymes reduce steatorrhea and are safe in patients who have malabsorbtion with small doses. Pediatr Pulmonol 1991; 10:79–85.
Exercise performance and breathing patterns in cystic fibrosis: Male‐female differences and influence of resting pulmonary function
Authors: Orenstein David M. , Nixon Patricia A.
Published: March 2007

Despite improved prognosis for patients with cystic fibrosis (CF), they continue to suffer from progressive decline in pulmonary function and exercise tolerance. Beyond puberty, female patients have greater loss of pulmonary function and higher mortality than males, yet no one has studied male‐female differences in exercise tolerance among patients. We therefore compared the responses to progressive exercise in 58 male and 52 female patients with CF and analyzed the influence of resting pulmonary function and gender on these responses and on breathing patterns during exercise. Within each of three pulmonary function groups (group 1: FEV1 ⩾ 65% predicted; group 2: FEV1 = 50–64% predicted; and group 3: FEV1 < 50% predicted), female patients had lower exercise tolerance than males. This was reflected in the overall group for each gender: males' peak work load was 130 ± 64 W, females' 111 ± 32 W (P = 0.04); males' peak oxygen consumption, 36.9 ± 11.4 mL/kg/min and females', 31.0 ± 7.4 mL/kg/min (P = 0.0006). There was no interactive effect between gender and pulmonary function. Neither respiratory rate nor tidal volume differed between sexes. Male and female patients, irrespective of disease severity, employed similar proportions of their ventilatory capacity at exhaustion; group mean minute ventilation to maximum voluntary ventilation ratio ranged from 62.9 to 78.3%, with no apparent relationship to disease severity. Pediatr Pulmonol 1991; 10:101–105.
Repeated provocation tests in asthmatic children for testing tachyphylaxis to histamine
Authors: Roorda Ruurd Jan , Gerritsen Jorrit , van Aalderen Wim M. C. , Schouten Jan P. , Knol Klaas
Published: March 2007

Tachyphylaxis to histamine was investigated in 16 children, aged 7–15 years, with mild asthma. Three consecutive histamine challenges were performed at intervals of 24 hours and 1 hour, respectively. No significant differences in IVC, FEV1, and PC20‐histamine values between the three measurements were observed. After a 24 hour interval there was no difference in percentage fall of FEV1, but there was a slight (not significant) decrease in fall of FEV1 after a 1 hour interval. The PC20‐histamine values showed good reproducibility with a 24 hour as well as with a 1‐hour period between the tests (geometric mean PC20, 2.04 mg/mL ± 3.50 %SD, 1.96 mg/mL ± 4.37 %SD, 2.17 mg/mL ± 4.12 %SD; correlation coefficients for a 24 hour interval, r = 0.87 and for a one‐hour interval, r = 0.94 (P < 0.01)).

We conclude that in children there is no strong evidence for tachyphylaxis to histamine. Our results differ from studies on tachyphylaxis in adult asthmatics. Possibly different mechanisms exist in children and in adults. Pediatr Pulmonol 1991; 10:106–111.
Sleep apnea and hypoxemia in recently weaned premature infants with and without bronchopulmonary dysplasia
Authors: Sekar K. C. , Duke James C.
Published: March 2007

Infants with bronchopulmonary dysplasia (BPD) experience significant hypoxemia. Apnea indices and oxygen saturation levels of ten infants with BPD were compared to ten healthy premature infants who were evaluated to rule out apnea or bradycardia prior to discharge from the hospital. Infants with BPD who had been recently (< 7 days) weaned from supplemental oxygen were evaluated on and off supplemental oxygen. Premature controls had never received oxygen nor ventilation assistance. Infants with BPD were born significantly more prematurely (28.1 ± 1.0 vs. 33.0 ± 3.9 weeks; P = 0.0012) while chronologic ages at the time of evaluation, adjusted for prematurity, were equal (37.1 ± 3.1 vs. 38.0 ± 2.7 weeks). Comparisons of apnea densities (expressed as percent of sleep time) between BPD and non‐BPD prematures revealed the following: neither the average obstructive apnea (0.15 ± 0.36 vs. 0.14 ± 0.31) nor periodic breathing densities (6.0 ± 8.56 vs. 10.2 ± 5.84) were different. Infants with BPD experienced significantly more central apnea (0.62 ± 0.34 vs. 0.16 ± 0.11; P = 0.003) than did non‐BPD prematures. Average oxygen saturation levels were significantly less among BPD vs. non‐BPD prematures (90.0 ± 10.18% vs. 95.7 ± 4.33%; P = 0.033). When supplemented with oxygen, BPD prematures had significantly higher saturation (X̄ = 94.5%) than when breathing room air (X̄ = 90.0%). Both central apnea and periodic breathing densities declined significantly with this improvement in saturation (0.64 vs. 0.04% and 6.0 vs. 1.4%, respectively). These data suggest that saturation status may indicate central respiratory stability in chronic lung disease. Pediatr Pulmonol 1991; 10:112–116.
Acute effect of passive smoking on lung function and airway responsiveness in asthmatic children
Authors: Oldigs Maike , Jörres Rudolf , Magnussen Helgo
Published: March 2007

The effect of a 1‐hour exposure at rest during passive cigarette smoking (20 ppm CO) or Sham was investigated in 11 children with bronchial asthma (age range, 8–13 yr; ten boys, one girl). Nine of the subjects were on regular therapy with inhaled β2‐agonists and disodium cromoglycate. Both drugs were withheld at least 6 hours prior to each study session. Exposure was performed in an environmental chamber. Before and immediately after exposure, lung function and symptom scores were determined. After exposure, a histamine inhalation challenge was performed to determine the concentrations that caused a 100% increase in SRaw (PC100SRaw) and a 20% fall in FEV1, (PC20FEV1). Mean (SD) SRaw before and after Sham was 8.7 (3.6) and 9.0 (3.2) cmH2O·s, and mean FEV1 (SD) was 1.97 (0.32) and 1.98 (0.40) L, respectively. Before and after cigarette smoking, mean SRaw (SD) was 10.4 (5.3) and 9.4 (3.3) cmH2O·s, and mean FEV1 (SD) was 1.95 (0.37) and 1.94 (0.35 L, respectively. Geometric mean (SD) PC100SRaw and PC20FEV1 after Sham was 1.39 (3.0) and 0.70 (2.7) mg/mL, and after passive smoking 1.65 (2.5) and 0.96 (2.3) mg/mL, respectively. There were no statistical differences in lung function and PC values between Sham and passive cigarette smoking. The main symptoms during passive smoking were irritation of the eye and the nasopharynx. Our observations suggest that in children with mild bronchial asthma 1 hour of passive cigarette smoking does not cause consistent changes of lung function and bronchial responsiveness. Pediatr Pulmonol 1991; 10:123–131.
Comparison of three methods for measuring respiratory mechanics in ventilated children
Authors: Seear Michael , Wensley David , Werner Heinrich
Published: March 2007

Continuous measurements of airway pressure, gas flow, and tidal volume were made in 22 mechanically ventilated children, both during steady state conditions and following airway occlusion at end‐inflation. For each child, three methods of analyzing the stored data were used to generate values of respiratory system compliance and resistance: 1) end‐inspiratory hold technique (Bone: Respir Care 28:597, 1983; Rossi et al. Am Rev Respir Dis 131:672, 1985); 2) constant flow technique (Rossi et al. J Appl Physiol 58:1849, 1985; Suratt et al. J Appl Physiol 49:1116, 1980); and 3) multiple linear regression (Roy et al. Comput Biomed Res 7:21, 1974; Bhutani et al. Pediatr Pulmonol 4:150, 1988). In the absence of an accepted standard, we used the inspiratory hold technique as a reference. All methods gave comparable values for respiratory mechanics over a wide clinical range. However, multiple linear regression was the most convenient of the three: it can be automated and continuously displayed, there is no subjective input, values are taken throughout the respiratory cycle, and it is completely noninvasive. We also found that respiratory system resistance was largely a measure of endotracheal tube resistance and that respiratory compliance is a more sensitive monitor of lung function in intubated children. Pediatr Pulmonol 1991; 10:291–295.
Longitudinal changes in lung function during the first three years of premature infants with moderate to severe bronchopulmonary dysplasia
Authors: Mallory George B. , Chaney Hollis , Mutich Rebecca L. , Motoyama Etsuro K.
Published: March 2007

Bronchopulmonary dysplasia (BPD) is a chronic obstructive pulmonary disease of prematurely born infants following prolonged mechanical ventilation and oxygen therapy. Developmental changes in pulmonary function of children with BPD during their early years have been difficult to study. We longitudinally studied maximal expiratory flow‐volume curves by the forced deflation technique in 11 infants who had previous tracheostomy with moderate to severe BPD. Patients were classified into: those who were mechanically ventilated for less than 5 months (Group A), and those who were ventilated for 10 or more months (Group B). At 6 months of age, forced vital capacity (FVC) was 28.1 and 25.5 mL/kg in Group A and B, respectively, significantly less than normal (41.8 mL/kg). The maximum expiratory flow at 25% FVC (MEF25) at 6 months of age was 6.9 and 8.1 mL · kg−1 · s−1 in Group A and B, respectively, (predicted value, 39.2 mL · kg−1 · s−1). FVC reached the normal range by 12 months of age in Group A, but remained lower until 36 months of age in Group B. MEF25 gradually increased in Group A, reaching 18.0 mL · kg−1 · s−1 at 36 months of age, whereas in Group B it was severely decreased at the same age (3.5 mL · kg−1 · s−1). More than 75% of the patients had airway hyperreactivity at all ages. We have demonstrated that in patients with moderate to severe BPD, vital capacity is moderately decreased, but catches up to normal levels by 36 months of age. In contrast, severe lower airway obstruction persists in all infants, although in those with moderate BPD gradual improvement is seen. These findings suggest that in BPD neither obstruction of the smaller intrathoracic airways nor bronchial hyperreactivity resolves during the first 3 years of life.Pediatr Pulmonol. 1991; 11 :&14.
Bronchial hyperreactivity in children with Marfan syndrome
Authors: König Peter , Boxer Robert , Morrison John , Pletcher Beth
Published: March 2007

Marfan syndrome is known to have pulmonary manifestations such as pneumothorax. There have been few previous studies of pulmonary function tests and none of bronchial hyperreactivity. Therefore, pulmonary function tests were performed in 11 children with Marfan syndrome and 11 normal children. Bronchial responsiveness was tested in ten of the Marfan patients by methacholine challenge test and response to bronchodilator. Because of disproportionate length of legs in Marfan patients, an “ideal” standing height was calculated from sitting height. Pulmonary function tests, as absolute values or as percent predicted based on “ideal” height, were not different in Marfan patients and normals, although a few individual patients had abnormal function (mostly airway obstruction and hyperinflation). Response to methacholine challenge was positive on forced expiratory volume in 1 second (FEV1), forced expiratory flow between 25 and 75% VC (FEF25–75%), and FEF50%, in 37.5%, 60%, and 70% of tests respectively. A significant response to bronchodilators was obtained in 40% of patients as measured by FEV1, in 90% by FEF25–75% and in 100% by FEF50%. Pulmonary function tests after bronchodilator were significantly higher when compared with values before the bronchodilator as well as with the baseline before methacholine. Therefore, most if not all patients with Marfan syndrome had hyperreactive airways in this relatively small group of patients. Even though only one patient had a diagnosis of asthma, six more had subtle symptoms. It is concluded that tests for bronchial hyperreactivity could be part of the routine investigation in Marfan syndrome. Further studies on larger numbers of patients are still needed. Pediatr Pulmonol. 1991;11 :29‐36
Effect of positive end‐expiratory pressure on respiratory compliance in children with acute respiratory failure
Authors: Sivan Yakov , Deakers Timothy W. , Newth Christopher J. L.
Published: March 2007

We studied the effect of positive end‐expiratory pressure (PEEP) on the compliance of the respiratory system (Crs) in 25 children (age, 3 weeks to 10 years) requiring mechanical ventilation. Functional residual capacity (FRC) measurements were performed at 2 cm H2O increments, from 0 to 18 cm H2O of PEEP, and the FRC values were regressed versus PEEP. Static Crs, Crs/kg, and specific compliance (Crs/FRC) were calculated for each PEEP level. When FRC normality was reached Crs/kg improved in 15/25 (60%) patients but decreased in 2/25 (8%). Overall, Crs/kg increased from a mean ± SE of 0.94 ± 0.09 to 1.35 ± 0.13 mL/cm H2O/kg (P = 0.003) and Crs/FRC from a mean ± SE of 0.067 ± 0.006 to 0.077 ± 0.007 mL/cm H2O/mL (P = 0.057).

The maximum compliance (mean Max Crs/kg, 1.56 ± 0.12 mL/cm H2O/kg, and mean Max Crs/FRC, 0.089 ± 0.005 mL/cm H2O/mL) was significantly higher than the compliance at the clinically chosen PEEP level and the compliance at the PEEP that normalized FRC. Maximum compliance was achieved within 4 cm H2O of the PEEP that normalized FRC. In 14/25 (60%) of cases the PEEP at maximum compliance coincided with the PEEP that resulted in FRC normalization.

We concluded that static respiratory compliance improves in most (but not all) children with acute respiratory failure when FRC is normalized. Static respiratory compliance reaches maximum levels at PEEP values that are close (but not equal) to those that result in FRC normalization. Thus, assessment of the effect of PEEP on compliance is required in individual patients.
Rib cage to abdominal asynchrony in children undergoing polygraphic sleep studies
Authors: Sivan Yakov , Ward Sally Davidson , Deakers Timothy , Keens Thomas G. , Newth Christopher J. L.
Published: March 2007

We assessed rib cage (RC) to abdominal (AB) asynchrony in 110 children, aged 1 to 50 months who underwent diagnostic daytime polygraphic sleep studies (PSG), and correlated the results. RC—AB asynchrony was calculated by the phase angile (PA) technique and compared to normal values (0–24°) derived from a separate group of 45 control children, matched for age and weight. Eighty‐two of the 110 patients had PSG as part of their evaluation for obstructive sleep apnea. There was a high association between the phase angles and the PSG results (P < 0.01; Fisher's exact test). PSG was abnormal in 38/82 patients (46%) and the phase angle was increased in 51/82 (62%) (mean ± SD, 68° ± 39°; range 28°–168°) compared to the normal controls (P < 0.001). Fourteen of the 110 patients had bronchopulmonary dysplasia; of these, PSG and PA results agreed in six normal and seven abnormal studies and disagreed in only one (P = 0.002). Six of 110 patients had Down's syndrome; 5 of 6 had increased RC—AB asynchrony, compared to 3 of 6 who had abnormal PSG. Eight of 110 patients were evaluated for central apnea and hypoventilation; PA was abnormal in 4 of 8, who also had abnormal PSG and in 1 with normal PSG. We conclude that RC—AB measurement by the PA technique may be an important adjunct to the evaluation of breathing disorders during sleep in small children and it may be a good screening test for small children who need PSG.
Importance of using lung function regression equations appropriate for ethnic origin
Authors: Greenough A. , Hird M. F. , Everett L. , Price J. F.
Published: March 2007

Functional residual capacity (FRC) can be assessed reliably in young children using a helium gas dilution technique. The aim of the present study was to determine if differences in lung volume are found in asthmatic children of different ethnic origins. Eighty‐eight children were studied, 53 of Caucasian origin and 35 of Afro‐Caribbean origin. Their median age was 6.1 years (range, 5.3–9.0 years). FRC measured by helium gas dilution is reported as a percentage of predicted for height, using a published regression equation as well as regression equations appropriate for the ethnic origin of the child. In the majority of both groups FRC was elevated above the ethnically appropriate regression equation for healthy children. The Caucasian children apparently had higher FRCs than the Afro‐Caribbean children if comparing the absolute lung volume, and if lung volume was expressed as percent of predicted for height, by a regression equation uncorrected for ethnic origin (P < 0.02). This difference disappeared when ethnically appropriate regression equations were used. We conclude that lung volumes are similar in asthmatic children of different ethnic origin and that it is important to use ethnically appropriate regression equations.
Antineutrophil elastase activity in cystic fibrosis serum
Authors: Cantin André M. , Lafrenaye Sylvie , Bégin Raymond O.
Published: March 2007

The antigenic concentrations of alpha‐1‐antitrypsin (α1AT) were measured in 13 patients with cystic fibrosis (CF) and in 11 healthy subjects. Serum α1AT was purified by immunoaffinity chromatography and the antielastase activity of the purified α1AT was determined by measuring the molar ratio necessary to inhibit human neutrophil elastase (HNE). The association rate constant of α1AT with HNE was determined in a timed assay. The capacity of CF serum α1AT to form complexes with porcine pancreatic elastase was studied by polyacrylamide gel electrophoresis. Antigenic concentrations of α1AT μmol/L were markedly increased in the serum of all patients with CF (61.9 ± 4.3 μmol/L) in comparison to a reference standard (36.7 ± 1.8 μmol/L; P < 0.0001). CF serum α1AT was fully active against HNE, and its association rate constant in the presence of HNE was similar to that of healthy subjects. In addition, CF serum α1AT formed complexes with porcine pancreatic elastase that were electrophoretically indistinguishable from those of normal serum α1AT. These results indicate that patients with CF have increased serum α1AT concentrations and that this antiprotease, when purified from serum, functions normally.
Variability of dynamic compliance measurements in spontaneously breathing and ventilated newborn infants
Authors: Ratjen F. A. , Wiesemann H. G.
Published: March 2007

We studied reproducibility and variability of dynamic pulmonary compliance (Cdyn) by making measurements with the esophageal balloon at multiple locations within the esophagus, in both spontaneously breathing and mechanically ventilated newborn infants. Reliable measurements could be obtained over a range similar to that reported for measurements with a liquid‐filled catheter. In spontaneously breathing infants Cdyn was found to be highly variable. This variability was unrealated to catheter position but was associated with concomitant changes in pulmonary resistance. Probably because of the high variability, the correlation of Cdyn with a measurement of respiratory system compliance (Crs) was rather poor (r = 0.63). Cdyn measured in mechanically ventilated infants was significantly less variable and compared favorably to Crs (r = 0.86), but its accuracy could not be adequately assessed since the comparison of esophageal and airway occlusion pressure was not feasible in all infants. In addition, significant differences in Cdyn were found between spontaneous and ventilated breaths during mechanical ventilation. Further studies in both ventilated and spontaneously breathing infants are needed to assess the variability of Cdyn over extended time periods. Pediatr pulmonol.1992; 12:73–80.
Time course of lipid‐laden pulmonary macrophages with acute and recurrent milk aspiration in rabbits
Authors: Colombo John L. , Hallberg Timothy K. , Sammut Paul H.
Published: March 2007

High levels of lipid‐laden macrophages (LLM) in bronchial washings have been associated with food aspiration. We studied the time course of appearance and clearance of LLM in rabbits undergoing either a single milk instillation, five weekly milk instillations or saline (control) instillations into the airways. Cells were obtained by bronchoalveolar lavage of intubated rabbits at uniform time intervals following the single or the last of five milk/saline instillations. LLM semi‐quantitative indexes were derived using oil‐red‐O staining. Significantly elevated indexes were found in both milk groups 6 hr after milk instillation. In the single saline and milk instillation groups the indexes were not different beginning on the 4th day, and indexes from 8 of 9 rabbits had returned to baseline by the 6th day. However, indexes remained significantly elevated up to 17 days in the group receiving weekly milk instillations. Indexes from all rabbits in the repeat milk instillation group remained elevated for 12 days or longer. This group also developed increased numbers of binucleated macrophages. Quantitation of LLM in this model appears to be a sensitive indicator of recurrent lipid aspiration, these cells remaining in the airways for several days after the last aspiration event.
Lung function measurements in awake compared to sleeping newborn infants
Authors: Lødrup K. C. , Mowinckel P. , Carlsen K. H.
Published: March 2007

Tidal breathing flow‐volume loops were recorded in 19 healthy newborn infants when awake and asleep. This preceded and followed measurements of passive lung mechanics (by single breath occlusion). Our aim was to evaluate possible differences in lung function due to state of arousal or any influence of the occlusion technique. Expiratory volumes and flow rates were larger in awake than in sleeping infants before, but not after occlusion measurements. In sleeping, but not in awake infants, expiratory volumes and flow rates were higher after occlusion than before. Respiratory system compliance was significantly larger in sleeping than awake infants, while differences in respiratory system resistance and airway plateu pressure did not reach a significant level. Our results show that lung function can be measured in awake as well as sleeping infants, but differs significantly according to their arousal state, and whether tidal expiratory flow measurements are performed before or after airway occlusion measurements. Separate reference values for awake and sleeping infants may, therefore, be required. Marked intrasubject variability was found in the occlusion measurements, and criteria for acceptable measurements need to be defined.
Estimation of arterial carbon dioxide by end‐tidal and transcutaneous P measurements in ventilated children
Authors: Sivan Yakov , Eldadah Maher K. , Cheah Teik‐ee , Newth Christopher J. L.
Published: March 2007

Simultaneous measurements of arterial, end‐tidal, and transcutaneous carbon dioxide (Pa, Pet, Ptc, respectively) were obtained in 134 children receiving mechanical ventilation (ages, 2 days to 16 years; mean, 2.5 years). The mean ± SD Pet± bias (Pa − Pet) was 3.4 ± 6.6 mmHg. When the Pet bias was plotted against the Pa/P ratio, a change in the scatter was obvious at about 0.3. The Pet bias for patients with Pa/P under 0.3 was 7.8 ± 7.3 mmHg compared to 0 ± 3.4 in patients with Pa/P above 0.3 (P < 0.001). Pet differed significantly from Pa (P < 0.001) only for patients with Pa/P under 0.3. The slope (Pa versus Pet) for these patients was 1.59, while the slope for patients with Pa/P above 0.3 coincided with the line of identity (1.00). The mean ± SD Ptc bias (Pa − Ptc) was − 1.3 ± 7.2 mmHg. Skin perfusion was recorded at the area close to the transcutaneous CO2 monitor electrode and was defined as normal when capillary refill was below 3 seconds. The Ptc bias for patients with normal skin perfusion was −0.2 ± 5.4 mmHg (P = 0.73) compared to −4.1 ± 9.9 for patients with decreased skin perfusion (P = 0.01). The slope of Ptc against Pa was closer to identity in patients with normal skin perfusion (1.17) than in patients where it was decreased (slope, 1.40). We suggest that Pa estimation by both Pet and Ptc is sufficiently precise and reliable for clinical use in critically ill children. Certain limitations stem from the nature of the techniques. Measurement of alveolar to arterial O2 ratio may improve the precision of Pa estimation by capnography; assessment of skin perfusion is important in order to increase the accuracy of the transcutaneous method, especially in critically ill children.
Airway responsiveness in infants following bronchiolitis
Authors: Tepper Robert S. , Rosenberg David , Eigen Howard
Published: March 2007

Airway responsiveness to inhaled methacholine was assessed in 18 infants, 4 and 10 months old, following bronchiolitis. Pulmonary function was measured from partial expiratory flow‐volume curves generated by the rapid compression technique. Sleeping infants inhaled increasing concentrations of methacholine until maximal expiratory flows at functional residual capacity (VmaxFRC) decreased by 30% or 2.5 mg/mL was inhaled. Airway responsiveness was quantitated by: 1) the threshold concentration (log TC) required to decrease VmaxFRC by 2 standard deviations from baseline; 2) the concentration required to decrease VmaxFRC by 30% (log PC30); and 3) the slope of the dose‐response curve between TC and PC30 (log SPC30). At both the first and second evaluation, the bronchiolitic infants had lower baseline VmaxFRC (% pred.) than 24 control infants. In addition, the bronchiolitic infants had heightened airway responsiveness compared to controls, demonstrating lower values for logTC and logPC30 and steeper slopes to their dose‐response curves (logSPC30). After accounting for the relationship between airway responsiveness and age, the occurrence of bronchiolitis was found to be a significant independent factor 10 months but not 4 months following bronchiolitis. The bronchiolitic infants did not demonstrate the decline in airway responsiveness with increasing age that occurs in normal infants. We conclude that infants exhibit heightened airway responsiveness following bronchiolitis. © 1992 Wiley‐Liss, Inc.
Prediction of the acute response to surfactant therapy by pulmonary function testing
Authors: Wallenbrock Mark A. , Sekar K. C. , Toubas Paul L.
Published: March 2007

We tested the hypothesis that pretreatment pulmonary function values would be predictive of the response to the synthetic pulmonary surfactant, Exosurf® (Burroughs Wellcome Co.) treatment of infants with respiratory distress syndrome (RDS). Pulmonary compliance and resistance were measured prior to Exosurf treatment in 40 infants with severe RDS. In 36 patients who survived for at least 24 hr the acute response to therapy was quantitated by calculated post‐treatment/pretreatment ratios of ventilator efficiency index (VEI) and arterial/alveolar oxygen tension ratios [Pa/A]. The values of these calculated response ratios 24 and 48 hr after treatment varied widely among individual patients. The magnitude of the response was not related to birthweight, gestational age, age at treatment, pretreatment VEI, pretreatment Pa/A, or pretreatment pulmonary compliance. However, the response to Exosurf as measured by improvements in Pa/A at 24 and 48 hr was related to pretreatment pulmonary resistance (r = −0.34, P < 0.05 and r = −0.60, P < 0.001), high pretreatment pulmonary resistance was associated with a poor response to Exosurf 24 and 48 hr after treatment. © 1992 Wiley‐Liss, Inc.
Nonbronchoscopic approach to bronchoalveolar lavage in children with artificial airways
Authors: Alpert Brad E. , O'Sullivan Brian P. , Panitch Howard B.
Published: March 2007

Bronchoalveolar lavage (BAL) performed with a fiberoptic bronchoscope (FOB) is a useful method for sampling alveolar contents. Since the smallest FOB with a channel has a diameter of 3.6 mm, BAL is difficult to accomplish through artificial airways (AA) < 5.0 mm I.D. We used a 4F balloon wedge pressure catheter to perform BAL through small AA. Supplemental O2 or ventilatory support was delivered via an adaptor through which the catheter was introduced. After it was passed distal to the AA, the balloon was inflated with normal saline (NS) to a predetermined volume, and advanced until resistance was felt. The balloon was deflated, advanced slightly, and then reinflated to achieve airway occlusion. Five aliquots of 0.75 mL/kg of NS were used for BAL. The procedure was performed in 20 children from 1 month (950 g) to 6½ years of age (median, 9 months). All specimens contained abundant alveolar macrophages, indicating good recovery of alveolar contents. Clinically significant information was obtained in 17 (85%) cases, and no patient required an open lung biopsy. In conclusion, nonbronchoscopic bronchoalveolar lavage is a valuable method for obtaining alveolar contents in children with small AA that preclude the use of an FOB, and it obviates the need for open lung biopsy in many patients. This technique could be used as a research tool for measuring constituents of alveolar contents in infants and small animals. © 1992 Wiley‐Liss, Inc.
Compact apparatus for measurement of ventilatory response to carbon dioxide in newborns and infants
Authors: Kobayashi Keiko , Katayama Masao , Miyasaka Katsuyuki
Published: March 2007

We developed a rebreathing system for measuring response to carbon dioxide (CO2) of newborns and infants for use at the bedside. The system based on Read's method is small, easy to operate, and includes a computer‐controlled gas switching sequence, computerized calculation, and display functions. © 1992 Wiley‐Liss, Inc.

We measured the CO2 response in 11 infants with or without apnea, who were born at 26–33 weeks gestation and were 12 to 215 days old at the time of the study. Our results suggest that the presence of apnea in premature infants may correspond to a low CO2 response.

The method was convenient for clinical use because it allowed an investigator to carry out bedside tests in only a few minutes. With our system we were able to assess respiratory center function in newborns and infants.
The effects of airway hyperresponsiveness, wheezing, and atopy on longitudinal pulmonary function in children: A 6‐year follow‐up study
Authors: Sherrill Duane , Sears Malcolm R. , Lebowitz Michael D. , Holdaway M. David , Hewitt Chris J. , Flannery Erin M. , Herbison G. Peter , Silva Phil A.
Published: March 2007

We examined growth of spirometric lung function in 696 children of European ancestry who were followed from ages 9 to 15 years and stratified according to their degree of responsiveness to methacholine inhalation challenge, atopic status, and respiratory symptoms. Subjects were participants in the longitudinal Multidisciplinary Health and Development Study in Dunedin, New Zealand. Forced expired volume in 1 second (FEV1), and vital capacity (VC) were measured at 9, 11, 13, and 15 years of age, concurrently with assessment of airway responsiveness determined by the concentration of methacholine causing a 20% fall in FEV1 (PC20 FEV1). Atopic status was assessed at age 13 by skin‐prick testing to 11 allergens. In children demonstrating airway hyperresponsiveness, FEV1 increased with age at a slower rate, and the FEV1/VC ratio had a faster rate of decline through childhood, compared to non‐responsive children. Subjects with positive skin tests to house dust mite and cat dander also had lower mean FEV1/VC ratios than the control group. Any reported wheezing was associated with slower growth of FEV1 and VC in males. We conclude that in New Zealand children with airway responsiveness and/or atopy to house dust mite or cat growth of spirometric lung function is impaired. © 1992 Wiley‐Liss, Inc.