bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid improvement of static compliance after surfactant treatment in preterm infants with respiratory distress syndrome
Authors: Baraldi Eugenio , Pettenazzo Andrea , Filippone Marco , Magagnin G. Piero , Saia O. Sergio , Zacchello Franco
Published: March 2007

Respiratory mechanics were measured in 20 preterm infants before and in the 24‐hr period after treatment with surfactant. All infants were enrolled in the rescue clinical trial with Curosurf® carried out in the Neonatal Intensive Care Unit. They received a dose of 200 mg/kg lipid surfactant intratracheally after birth. Static compliance of the respiratory system (Crs) was measured by the single breath occlusion technique during both spontaneous and mechanical ventilation. Resistance of the respiratory system (Rrs) and expiratory time constant (Trs) were also measured. As early as 3 hr after surfactant administration a significant improvement of 45% in Crs measured during mechanical ventilation (CrsV) was noted (0.40 ± 0.14 vs 0.58 ± 0.17 mL/cm H2O/kg, P < 0.001), together with a significant improvement of the arterial/alveolar O2 tension ratio (Pa/Ao2) (0.12 ± 0.03 vs 0.30 ± 0.16. P < 0.01). The improvement of CrsV and Pa/Ao2 was confirmed 24 hr later (0.55 ± 0.15 mL/cm H2O/kg and 0.33 ± 0.18, respectively). A significant correlation was found between Crs and Pa/Ao2 ratio (r = 0.56, P < 0.001). Time constant values were significantly higher after surfactant treatment (0.15 ± 0.07 vs 0.09 ± 0.03 sec; P < 0.01). Rrs remained unchanged. These data indicate that Curosuf® given intratracheally after birth determines a rapid improvement of respiratory mechanics as soon as 3 hr after dosing, together with the improvement of oxygenation. From the findings obtained with the present study we show evidence that respiratory system mechanics may be a useful physiological measure to guide ventilatory strategy following surfactant therapy. © 1993 Wiley‐Liss, Inc.
Assessment of forced expiratory volume — time parameters in detecting histamine‐induced bronchoconstriction in wheezy infants
Authors: Turner Debra J. , Sly Peter D. , Lesouëf Peter N.
Published: March 2007

A new technique recently introduced allows the measurement of infant lung function from lung volumes raised by a pump prior to generation of forced expiratory flow‐volume (FEFV) curves. Forced expiratory volume‐time (FEV1) parameters rather than traditional flow parameters are used. The aim of this study was to assess the usefulness of FEV, parameters in detecting airway responsiveness to histamine in recurrently wheezy infants. Ten infants (age 7–18 months) sedated with 80 mg/kg chloral hydrate underwent a histamine inhalation challenge. Throughout the challenge FEFV curves were generated from end‐tidal inspiration. Raised FEFV curves, from a lung volume preset by 15 cmH2O inflation pressure, were gathered at baseline and after the final concentration of histamine. The mean fall from baseline was 47% in maximal flow at functional residual capacity (VmaxFRC) (P < 0.0005), 15.5% in FEV0.5 (P < 0.000l), 13.5% in FEV0.75 (P < 0.005), and 11.0% in FEV1.0 (P = 0.057), after the final concentration of histamine delivered. Tidal volume and inspiratory volume reached above FRC between pre‐ and posthista‐mine did not change. Mean oxygen saturation fell significantly from 97 to 93%. We conclude that FEV1 parameters adequately detect reduced lung function during histamine‐induced bronchoconstriction and appear suitable for histamine challenge testing in infants. © 1993 Wiley‐Liss, Inc.
Comparison of the squeeze technique and transcutaneous oxygen tension for measuring the response to bronchial challenge in normal and wheezy infants
Authors: Clarke Jane R. , Reese Amanda , Silverman Michael
Published: March 2007

The aim of this study was to compare the fall in transcutaneous oxygen tension (Ptco2) as an outcome measure during bronchial provocation with histamine, with changes in airway function measured by the squeeze technique in healthy infants and those with wheezing disorders. Ptco2 was measured during histamine challenge in 20 infants, aged 6–16 months, of whom 14 had recurrent cough or wheeze (lower respiratory illness, LRI), and 6 were healthy. All were symptom free at the time of testing. The minimum value of Ptco2, after each nebulization was compared with the minimum baseline value. The response to increasing concentrations of histamine was also assessed by measuring maximal flow at functional residual capacity (VmaxFRC) by the squeeze technique. The inhaled concentration of histamine causing a 30% fall in VmaxFRC was calculated to give the provoking concentration (PC30). Baseline VmaxFRC was lower in symptomatic infants (117 mL/s) than the normal infants (322 mL/s; P <: 0.005), but the PC30 was not significantly different (7.7 and 5.7 g/L, respectively). There was no difference in baseline Ptc02 between the two groups. The infants with LRI had significant reductions in Ptc02 at both the final and preceding concentrations of histamine, whereas the normal infants had a significant and smaller reduction in Ptco2 only at the provoking concentration. Reduction in Ptc, during bronchial challenge was a less sensitive index of bronchial response in healthy infants than in infants with a history of recurrent LRI. © 1993 Wiley‐Liss, Inc.
Cytokines in sputum and serum from patients with cystic fibrosis and chronic pseudomonas aeruginosa infection as markers of destructive inflammation in the lungs.
Authors: Kronborg Gitte , Hansen Morten B. , Svenson Morten , Fomsgaard Anders , Hsiby Niels , Bendtzen Klaus
Published: March 2007

The presence of interleukin (IL)–1 receptor antagonist (IRAP) in plasma and sputum from patients with cystic fibrosis (CF) and chronic Pseudomonas aeruginosa lung infection was investigated together with IL‐lα, IL‐1β, IL‐6, and tumor necrosis factor‐α (TNF) in a cross‐sectional study. All cytokines were assayed by ELISAs. High concentrations of IRAP, IL‐lα, IL‐1β, IL‐6, and TNF in sputum samples and low or nondetectable levels of circulating cytokines were frequently found. Increased concentrations of plasma RAP are positively correlated with decreasing pulmonary function. In a longitudinal study of serum IRAP, a higher level of RAP was detected in a group of patients with poor pulmonary function compared to a group with good pulmonary function. © 1993 Wiley‐Liss, Inc.
The effect of maternal exercise on somatic growth and lung development of fetal rats: Morphologic and morphometric studies
Authors: Nagai Atsushi , Sakamoto Kyoichi , Konno Kimio
Published: March 2007

Our study was aimed at elucidating the effect of strenuous maternal exercise (running at a speed of 20 m/min) on fetal somatic growth and lung development. Dams were separated into three groups: (1) exercising during the entire course of pregnancy: (2) exercising from the 16th to the 20th gestational day: and (3) controls treated in the same manner as the exercising animals, but not exercised. There were no differences in the mother's body weight (mother's body weight total body weight of the fetuses) among the three groups. Overall growth and lung development in fetuses from mothers that exercised during the entire course of pregnancy showed markedly decreased size and weight of body and lung, smaller air spaces and thicker future alveolar walls, and fewer osmiophilic lamellated bodies in alveolar type II cells. The morphometric data of fetuses from mothers that had exercised only during late gestation were similar to those of control animals. The ratio of fetal lung volume to body weight was the same in all three groups. These findings indicate that long‐term strenuous maternal exercise induces retardation of fetal lung development, possibly accompanied by a disturbance of overall growth. Maternal exercise represents another means of manipulating lung development. © 1993 Wiley‐Liss, Inc.
Forced expiratory flows and lung volumes in normal infants
Authors: Tepper Robert S. , Reister Teresa , Angelicchio‐Keller C. , Kisling J.
Published: March 2007

Forced expiratory flows at functional residual capacity (VmaxFRC) by the rapid compression technique and functional residual capacity (FRC) by the helium dilution technique were assessed in 112 normal infants with a mean age of 10.7 months (range, 1.0–31.0). In predicting FRC, log transformation was appropriate and body length was the best predicator. For VmaxFRC, age was a better predictor than length, and logarithmic transformation was not required. magnified image

There were no gender differences for FRC or VmaxFRC; however, male infants exposed to passive cigarette smoke tended to have lower flows than male infants not exposed (P < 0.07). This study establishes normative values for VmaxFRC and FRC in infants between 1 and 31 months of age, and suggests that passive cigarette smoke exposure has an adverse effect upon forced expiratory flows in male infants. © 1993 Wiley‐Liss, Inc.
A common presentation of an uncommon cause of neonatal respiratory distress: Pneumonia alba
Authors: Edell Dean S. , Davidson James J. , Mulvihill Denise M. , Majure Marc
Published: March 2007

While lung involvement is an uncommon presentation of congenital syphilis, respiratory distress is a common leading symptom in sick newborns. We describe an infant who presented with respiratory distress thought to be secondary to congenital syphilis and discuss the findings suggestive of an etiology other than respiratory distress syndrome (RDS). © 1993 Wiley‐Liss, Inc.
Gender related differences in airway tone in children
Authors: Landau Louis I. , Morgan Wayne , McCoy Karen S. , Taussig Lynn M.
Published: March 2007

The effects of gender, volume history, and inhaled atropine and isoproterenol on lung mechanics were assessed in 16 normal boys and 14 normal girls using lung volumes, flow‐volume curves, and oscillatory resistances. Flows were measured from full and partial forced expiratory flow‐volume curves. Six girls and 6 boys were studied before and after inhaled atropine, and 10 boys and 8 girls before and after inhaled isoproterenol. Girls demonstrated a significant increase in flows on full and partial curves with a deep inspiration vmax‐partial 0.73 ± 0.34 (SD) to Vmax‐fullO.80 ± 0.37 and 0.83 ± 0.20 to 1.06 ± 0.29 TLC/s in each group and following inhalation of isoproterenol on the partial curves only (0.73 ± 0.34 to 0.93 ± 0.40 TLC/s). Boys showed a small but significant increase in Vmax with isoproterenol on full curves but not on partial curves. Following atropine, boys demonstrated a significant increase in Vmax on partial flow‐volume curves (0.78 ± 0.28 to 1.00 ± 0.35 TLC/s) and a significant decrease in specific respiratory resistance (7.6 ± 2.7 to 5.1 ± 0.9 cmH2O/s), whereas girls had no such changes. These data suggest that boys have greater resting air way tone than girls and that this tone is less responsive to deep inspiration and isoproterenol independently, although a combination of isoproterenol and a deep inspiration will produce increased flows in boys. Atropine reduces airway tone predominantly in boys, suggesting that the increased resting airway tone in boys is partially mediated via the vagus nerve. Pediatr Pulmonol. 1993; 16:31–35. © 1993 Wiley‐Liss, Inc.
Longitudinal evaluation of pulmonary function in infants and very young children with cystic fibrosis
Authors: Tepper Robert S. , Montgomery Gary L. , Ackerman Veda , Eigen Howard
Published: March 2007

Thirty‐two infants with cystic fibrosis (CF) had pulmonary function testing and chest radiographs at the time of diagnosis and on average 1 year later, when they had no acute respiratory symptoms. At diagnosis, 14 of 32 infants had respiratory symptoms (RESP) and 18 did not have respiratory symptoms (NRESP). There were no significant differences in age, weight, or length between the RESP and NRESP groups. At diagnosis, the RESP group had significantly lower forced expiratory flows compared to the NRESP group (41±32% vs. 98±48 % predicted); however, there were no significant differences in functional residual capacity or chest radiographic scores. Between diagnosis and follow‐up, the NRESP group had no significant change in pulmonary function but a decline in chest roentgenographic (CXR) scores (22±2 to 21±2). For infants in the RESP group, there were no significant changes in FRC or CXR score. Maximal expiratory flow at functional residual capacity (Max FRC) rose from diagnosis to 1 year follow‐up (41±32 % to 74±27 % predicted; P < 0.002); however, at follow‐up flows for the RESP group remained significantly lower than flows for the NRESP group (74 % vs. 113 % predicted; P < 0.0.005). For the 32 infants with CF, there was significant correlation between percent predicted Max FRC at follow‐up and at diagnosis (r = 0.47; P<0.02). Those infants with lower percent predicted flows at diagnosis were more likely to have lower percent predicted flows 1 year later. Flows at follow‐up were not related to a family history of asthma or to passive smoke exposure. We conclude that the potential benefits of early diagnosis by neonatal screening and the choice of therapeutic interventions early in life will depend upon the causes of the relationship between low flows at diagnosis and at follow‐up. Pediatr Pulmonol. 1993; 16:96–100. © 1993 Wiley‐Liss, Inc.
Polysomnography in obese children with a history of sleep‐associated breathing disorders
Authors: Silvestri Jean M. , Weese‐Mayer Debra E. , Bass Michelle T. , Kenny Anna S. , Hauptman Susan A. , Pearsall Sheilah M.
Published: March 2007

We hypothesized that obese children with a history of breathing difficulty during sleep would demonstrate (1) evidence of complete and partial obstructive sleep apnea (OSA) with hypercarbia and/or hypoxemia; and (2) correlation between symptoms, degree of obesity, adenoid and tonsil size, and polysomnography (PSG) results. We evaluated 32 obese children [% ideal body weight (IBW), 196±45%] with a sleep history questionnaire, airway radiographs, electrocardiograms (ECG), and PSG. By history, we found snoring (100%), difficulty breathing (59%), sweating (44%). restlessness (53%), arousals (41%), apnea (50%), worsening with upper respiratory infection (URI) (81%), hypersomnolence (59%), and mouth breathing (59%). We found adenoid and/or tonsil enlargement on 75% of airway x‐ray pictures. ECGs were abnormal in 5 patients. Among all patients, mean sleep study oxyhemoglobin saturation (SaO2) was 85±16% and mean end‐tidal CO2 (PetCO2 ) was 51±7 torr; 84% had paradoxical inward movement of the chest on inspiration, 59% had OSA, and 66% had partial OSA. In those with ⩾200% IBW and adenotonsillar enlargement, elevated PetCO2 and the presence of hypoxemia (SaO2<90%) for ⩾5% of the total sleep time (TST) were correlated, unlike in patients of similar weight but without adenotonsillar enlargement. Individual symptoms did not correlate with the severity of PSG abnormalities. By discriminant analysis, using three variables (IBW, presence of adenotonsillar tissue, and presence of ⩾5 symptoms), we could predict PSG abnormalities with up to 81% reliability. Our findings indicate that in obese children, particularly those with %IBW ⩾200 and adenotonsillar hypertrophy, with sleep‐disordered breathing evaluation by polysomnography should be considered. Pediatr Pulmonol. 1993; 16:124–129. © 1993 Wiley‐Liss, Inc.
Effect of obesity on pulmonary function in children
Authors: Inselman Laura S. , Milanese Ann , Deurloo Antoinette
Published: March 2007

The effect of obesity on pulmonary function was studied in 13 children, aged 8‐15 years, with 147‐300% ideal body weight (IBW). Measurements included lung volumes, airflow rates pre‐ and post‐bronchodilator nebulization, diffusing capacity (DLCO), maximal voluntary ventilation (MW), minute ventilation V̇E), and resting energy expenditure (REE). When compared with predicted normal values for sex, height, and body surface area (BSA), decreases (mean % predicted,±SE) were observed in expiratory reserve volume (ERV, 36±5); forced expiratory volume in 1 second (FEV1, 73±5); forced expiratory flow between 25% and 75% of vital capacity (FEF25‐75% 70±6); DLCO, absolute (52±3) and corrected (DLCO/VA, 71±5); and MVV (62±5). Residual volume (RV), RV/total lung capacity (TLC), VE, and REE were elevated. Other lung volumes were normal. Thus, obese children have altered pulmonary function, which is characterized by reductions in DLCO and ventilatory muscle endurance and airway narrowing. These alterations may reflect extrinsic mechanical compression on the lung and thorax, and/or intrinsic changes within the lung. The reduced DLCO may result from decreases in alevolar surface area relative to lung volume. Pediatr Pulmonol. 1993; 16:130–137. © 1993 Wiley‐Liss, Inc.
The effects of bedside pulmonary mechanics testing during infant mechanical ventilation: A retrospective analysis
Authors: Rosen William C. , Mammel Mark C. , Fisher Joel B. , Coleman J. Michael , Bing Dennis R. , Holloman Keith K. , Boros Stephen J.
Published: March 2007

We examined the effects of regular bedside testing of pulmonary mechanics (PM) on the outcome of 468 acutely ill, mechanically ventilated neonates. During the first of two 18‐month study periods, 217 infants were mechanically ventilated without the assistance of PM measurements. During the second 18‐month period, 251 infants were ventilated with the assistance of at least daily PM measurements. Using data obtained from the PM tests, we adjusted the infants' ventilators to maintain tidal volume, inspiratory time, and pressure‐volume loops within predetermined limits. With the exception of the PM measurements, given the limitations of retrospective analyses, both groups of infants received identical medical and nursing care. The infants ventilated with the assistance of PM testing developed fewer pneumothoraces (4.0%; 10/251) vs. no PM testing, 10.1 % (22/217); P < 0.05 by Chi‐square analysis. Infants weighing less than 1,500 g ventilated with the assistance of PM measurements had less intraventricular hemorrhage (IVH) overall, most notably, less grades I and II IVH (total IVH‐PM testing, 39.1% vs. no PM testing, 65.7%; P < 0.01; Grades I‐II IVH‐PM testing, 30.4% vs. no PM testing, 54.9%; P < 0.01). IVH incidence was decreased independent of pneumothorax occurrence. Survival rates, incidences of bronchopulmonary dysplasia, and durations of mechanical ventilation and hospitalization were similar. This retrospective analysis suggests that PM testing during infant mechanical ventilation reduces common acute ventilator‐associated complications. Pediatr Pulmonol. 1993; 16:147–152. © 1993 Wiley‐Liss, Inc.
Continuous end‐tidal CO2 in pediatric bronchoscopy
Authors: Franchi Luis M. , Carlos Maggi J. , Nussbaum Eliezer
Published: March 2007

In recent years flexible fiberoptic bronchoscopy (FFB) has been applied to children for diagnostic and therapeutic purposes. Sedation during FFB. along with the introduction of the bronchoscope into the pediatric airway, may cause hypoventilation, leading to hypoxia and desaturation, even in the presence of oxygen supplementation. Arterial oxygen saturation is usually monitored by pulse oximetry (S) during FFB. End‐tidal P (P) monitoring is not routinely used. Twenty‐two pediatric patients (15 days to 18 years old) undergoing FFB and receiving supplemental oxygen were studied prospectively and had continuous P and S measured before and during the procedure (bronchoscope at the carina or either main bronchus). Mean P (±SD) decreased from 33.9 (±6.0) mmHg before to 27.1 (±12.1) mmHg during the procedure (P < 0.024). Concomitantly, mean S (±SD) also decreased from 99.9 (±0.4)% before to 95.7 (±11.1)% during the procedure (P < 0.015). P changes seemed to precede the variations in S, especially in young patients who experienced significant desaturation and decompensation during FFB. We conclude that P and S decrease during FFB in children, even with supplemental oxygen. We speculate that this reflects airway obstruction by the instrument. Further studies are needed to assess the utility of P monitoring in pediatric FFB. Pediatr Pulmonol. 1993; 16:153–157. © 1993 Wiley‐Liss, Inc.
The effect of age on oxygen desaturation during histamine inhalation challenge in normal infants
Authors: Young Sally , Geelhoed Gary C. , Stick Stephen M. , Landau Louis I. , Lesouéuf Peter N.
Published: March 2007

Arterial oxygen saturation (S) is usually measured during inhalation challenges in infants as desaturation has been demonstrated with provoked bronchoconstriction. We wished to examine whether measurement of S would provide a simple noninvasive indicator of respiratory function (RF) changes occuring during inhalation challenge in infants. Histamine inhalation challenges were performed longitudinally in 22 normal healthy infants at 4 and 26 weeks of age. RF was measured by calculating maximum forced expiratory flow at functional residual capacity (VmaxFRC) using the rapid thoracic compression technique. Airway responsiveness was assessed using histamine; the provoking concentration (PC) was that which caused a fall in VmaxFRC of at least 40% from baseline. The provocative concentration for an exact fall of 40% in VmaxFRC (PC40) from baseline was derived by linear interpolation. S was continuously monitored by pulse oximetty. One month old infants had higher S levels throughout the inhalation challenge in comparison to their S levels at 6 months of age. Significant falls in S, were observed at the PC at both ages. However, at the age of 26 weeks the infants had greater median falls in S [PC, 4.5% (95%Cl: 3.0, 7.0)] compared to the response at age 4 weeks [3.0% (95%Cl: 1.0, 4.0) (P < 0.01)]. Median falls in VmaxFRC at the PC were not different between the ages. These results indicate an age‐dependent discordance between airway and S response in healthy infants during histamine‐induced bronchoconstriction. Pediatr Pulmonol. 1993; 16:158–162. © 1993 Wiley‐Liss, Inc.
Continuous positive airway pressure by nasal prongs in bronchiolitis
Authors: Soong Wen‐Jue , Hwang Betau , Tang Ren‐Bin
Published: March 2007

Ten infants with evidence of impending respiratory failure from severe bronchiolitis were successfully treated with continuous positive airway pressure (NCPAP) with double nasal prongs. Their mean (SD) age was 6.7 (3.8) months and mean (SD) body weight was 7.1 (2.1) kg. Respiratory assessments were made immediately before and 2 hours after application of NCPAP. Clinical symptoms, signs, and arterial blood gases improved in all patients, with a significant fall in mean (SD) respiratory rate [71 (6) vs. 54 (9) per minute], mean (SD) heart rate (178 (9) vs. 154 (15) per minute], and mean (SD) partial pressure of arterial carbon dioxide (Pa; 48.0 (13.9) vs. 42.4 (12.9) mmHg]. There was a significant rise in mean (SD) arterial blood pH 33 (0.05) vs. 7.37 (0.05)) and mean (SD) oxygenation ratio [Fio2/Pao2, 155 (25) vs. 175 (22)]. We believe NCPAP is an effective method, with numerous advantages in the treatment of severe bronchiolitis. Early application of NCPAP is suggested to avoid the need for mechanical ventilation. Pediatr Pulmonol. 1993; 16:163–166. © 1993 Wiley‐Liss, Inc.
Comparison of helium dilution and nitrogen washout measurements of functional residual capacity in premature infants
Authors: Yuksel B. , Greenough A. , Chan V. , Russell R. Ross
Published: March 2007

Comparison has been made of measurements of functional residue capacity (FRC) by a helium gas dilution (He) and a nitrogen washout (N2) technique. Twenty infants (median gestational age, 29.5 weeks) were studied at a median postnatal age of 25 days. No infant was oxygen dependent. The coefficient of repeatability of FRC (He) was 6.4 mL/kg and of FRC (N2), 6.3 mL/kg. The coefficient of repeatability of the two methods combined was 13.8 mL/kg. In 10 infants the results of two techniques differed by more than 20% of the mean FRC; those infants were born at a significantly earlier gestation than the rest of the cohort (P < 0.01). We conclude that, except in very immature infants, techniques for measuring FRC (He) and FRC (N2) yield reproducible and comparable results in convalescent premature infants. Pediatr Pulmonol. Pediatr Pulmonol. 1993; 16:197–200. © 1993 Wiley‐Liss, Inc.
Regional Distribution of Myosin Heavy Chain Isoforms in Rib Cage Muscles as a Function of Postnatal Development
Authors: Vazquez Roger L. , Daood Molly , Watchko Jon F.
Published: March 2007

We studied the expression of myosin heavy chain (MHC) isoforms, utilizing electro‐phoretic methods, in rib cage (RC) muscles: the scalenus medius, the parasternal, cephalic, midthoracic, and caudal intercostal muscles; and in the diaphragm (DI) of rats during postnatal development and when mature. At day 1, all RC muscles and the DI expressed MHC neonatall embryonic (6942% of total MHC complement) with little MHC slow and 2A; the RC muscles alone expressed a small proportion of MHC 2B (24%). On day 4, MHC neonatallembryonic expression still predominated (55–71%) but increased MHC 2A expression was observed in both the RC (11–21%) and DI (31%); MHC 28 (57%) was noted in the RC muscles but not the DI. By day 14, MHC neonatallembryonic and 2A expression each comprised a third of the total MHC complement of the RC muscles, MHC 2X was first observed, and MHC 2B expression increased. The day 14 DI was comprised of equal proportions of MHC neonatal/embryonic, slow and 2A with little MHC 2X (11%). The adult and day 30 animals expressed comparable muscle‐specific MHC phenotypes: the DI characterized by a proportional mixture of MHC slow, MHC 2A, and MHC 2X, with little MHC 26, whereas the RC muscles expressed predominately MHC 28 (40–62%). We conclude that the RC muscles and DI show comparable MHC phenotypes in the immediate newborn period but differ in their MHC expression during postnatal development and when mature. The RC muscles show only minor intermuscle variations in MHC phenotype during development, and when mature are characterized by fast MHC isoform expression, particularly MHC 2B. Pediatr Pulmonol. 1993; 16:289–296. © 1993 Wiley‐Liss, Inc.
Low‐frequency vs. High‐frequency respiratory mechanics after methacholine challenge in artificially ventilated rabbits
Authors: Belaguid A. , Marchal F. , Mazurek H. , Hascoet J. M. , Peslin R.
Published: March 2007

Respiratory system resistance (Rrs) and elastance (Ers) were estimated by two methods, before and after methacholine in six anesthetized, paralyzed, and artificially ventilated rabbits. Rrs and Ers, were obtained (1) by multiple linear regression analysis of the relationship between tracheal pressure and tidal volume and flow [Rrs (mlr)], Ers (mlr), and (2) by analysis of the Fourier transforms of tracheal pressure and flow resulting from 4 to 30 Hz pseudorandom pressure oscillations delivered by an Infant Star respirator [Rrs(os), Ers(os)]. Rrs (os) was significantly lower than Rrs (mlr). For instance, Rrs (os) at 20 Hz [Rrs (os)20] was (mean±SD) 17.3±3.5 vs 21.4±3.6 cm H2O · L−1 · s (P < 0.01) for Rrs (mlr). Ers (os) was significantly higher than the respective value obtained by multiple linear regression (718.2±81.0 vs 403.7±43.0 cm H2O L−1; P < 0.01). After methacholine, the changes of respiratory mechanics were similar with both methods. Rrs (mlr) and Rrs (os)20 increased respectively by 131±45 and 134±76%, and Ers(mlr) and Ers(os) increased respectively by 63±7 and 54±13%. A significant correlation was observed between Rrs(mlr) and Rrs (os)20 (r = 0.97) and between Ers (mlr) and Ers(os) (r = 0.96). We conclude that positive response to methacholine may be detected by forced oscillation as well as by multiple linear regression. However, the identified physiological components of the lung response (alteration in lung viscoelastic properties, increased lung inhomogeneity or increased intrathoracic airway shunt) are likely to be different with each method. Pediatr Pulmonol. 1993; 16:297–302. © 1993 Wiley‐Liss, Inc.
The effect of instrumental dead space on measurement of breathing pattern and pulmonary mechanics in the newborn
Authors: Marsh Michael J. , Ingram Dorothea , Milner Anthony D.
Published: March 2007

The effect of the instrumental dead space on breathing pattern and the values of pulmonary mechanics was evaluated because of concern about the relatively large dead space of 26 mL in a commercially available system. Sixty‐three healthy newborn infants were studied with a system as commercially supplied, and with the dead space eliminated using a 2 L/min biased flow. This led to a significant reduction in mean (± SD) values of respiratory rate from 56.8 (±11.7) to 48.2 (±11.7) breath/min (P < 0.0001), tidal volume from 5.2 (±1.3) to 4.9 (±0.9) mL/kg (P < 0.05), minute volume from 284 (±68) to 220 (±63) mL/min/kg (P < 0.0001), and work of breathing from 13.7 (±6.6) to 11.8 (±7.6) g · cm/kg (P < 0.02). There was a significant increase in dynamic lung compliance from 5.2 (±1.5) to 5.6 (±1.2) mL/cm H2O (P < 0.01) but no difference for total pulmonary resistance 39.6 (±22.8) and 38.8 (±22.2) cm H2O/L/sec. This shows that the instrumental dead space prevents measurement of the basal breathing patterns and alters the values of pulmonary mechanics. It is, therefore, important to use equipment with low dead space or make efforts to remove it by using a biased flow system such as we describe when measuring breathing patterns and pulmonary mechanics in the newborn. Pediatr Pulmonol. 1993; 16:316–322. © 1993 Wiley‐Liss, Inc.
Severe hypoxemia in children with upper airway obstruction during sleep does not lead to significant changes in heart rate
Authors: D'Andrea Lynn A. , Rosen Carol L. , Haddad Gabriel G.
Published: March 2007

Life‐threatening cardiac arrhythmias, including bradyrhythmias, are well‐known sequelae of obstructive sleep apnea syndrome (OSAS) in adults and are associated with apnea and severe hypoxemia. Since the clinical expression of OSAS in children is different, we questioned whether arrhythmias are a common feature of pediatric OSAS. Therefore, we analyzed R‐R interval patterns from 12 subjects (age 8 months to 14 years) with OSAS in detail. The diagnosis of pediatric OSAS is based on clinical signs of loud snoring and paradoxical respiratory efforts, as well as elevated end‐tidal carbon dioxide tension (PETCO2) and major phasic decreases of oxyhemoglobin saturation (SaO2). Two hundred and nine episodes of severe hypoxemia, defined as SaO2 values ⩽85% lasting ⩾30 seconds, were identified. Only 29 (14%) of these episodes were associated with obstructive apneas. The R‐R intervals were analyzed before and during each desaturation. Compared to baseline, mean and minimum R‐R intervals (RR,mean, RRmin) decreased during the desaturation episodes (P < 0.05), while maximum R‐R interval (RRmax) increased (P < 0.05). Although the absolute changes in all parameters were significantly different from baseline, the magnitude of these changes was small, with a mean of −5.3%, −12.2%, and 10.4% for RRmean, RRmin, and RRmax, respectively. No child had life‐threatening arrhythmias. Although severe hypoxemia existed in these children, the magnitude of the R‐R interval changes was modest, and profound bradycardia as described in adults, was rare. We conclude that in children with suspected OSAS, changes in R‐R interval and presence of life‐threatening arrhythmias cannot be used as a screening tool to assess the severity of disease or blood gas abnormalities. We speculate that the difference in heart rate patterns between children and adults may depend, in part, on the degree of airway closure and associated changes in pleural pressure. Pediatr Pulmonol. 1993; 16:362–369. © 1993 Wiley‐Liss, Inc.
C‐reactive protein is not a useful indicator of intermittent bacterial colonization in early lung disease of patients with cystic fibrosis
Authors: Watkin S. L. , Elborn J. S. , Cordon S. M. , Hiller E. J. , Shale D. J.
Published: March 2007

C‐reactive protein (CRP) is a general marker of the systemic inflammatory response to bacterial infection. Serial measurement of CRP is useful in monitoring respiratory exacerbations in patients with cystic fibrosis (CF) and chronic infection with Pseudornonas aeruginosa. We hypothesized that regular monitoring of CRP in young children with CF prior to colonization with P. aeruginosa might provide an objective guide to the need for antibiotic treatment. Twenty‐two children were studied prospectively over a 6 month period. We measured CRP every 2 months and at the beginning and end of respiratory exacerbations. In samples taken when the children were well, median CRP was 0.45 μg/mL compared with 1.92 μg/mL when they were symptomatic with positive culture results (P < 0.05). Despite this difference there was considerable overlap between CRP levels for infected and noninfected patients. A CRP value of >1.82 μg/mL (the upper 95% confidence interval for a control group of well children without CF) had a sensitivity of 49% and a specificity of 83% in determining a symptomatic exacerbation. We conclude that in this group of patients CRP measurements were of little value in monitoring respiratory exacerbations in patients who become intermittently infected with either Haernophilus influenzae or Staphylococcus aureus. Pediatr Pulmonol. 1994; 17:6–10. © 1994 Wiley‐Liss, Inc.
Perinatal lung development following maternal exposure to methylmercuric chloride
Authors: Das R. M. , Scott J. E.
Published: March 2007

Mercury ingested from dietary sources has potent neurotoxic and teratogenic effects. Initial studies have shown that mercury may also affect fetal lung development. Since these pulmonary effects may play a role in subsequent neonatal morbidity and mortality due to compromising of the development of the lung, mercury effects in fetal and neonatal lung were investigated. Methylmercuric chloride (MMC), 1,000 ppm (15 mg/kg of body weight), was administered via an intragastric tube to timed‐pregnant Swiss/Webster mice on day 9 of gestation. Lungs from fetuses on gestational day 18 and from neonates on days 1, 5, or 10 after birth were studied. Significant changes in MMC‐exposed lungs compared to controls occurred at postnatal day 1. At this time, lung weight per gram body weight increased, phospholipid content per gram of lung or per microgram of DNA decreased, while DNA per gram of lung increased. Methylmercury appears to have delayed lung maturation. Cuboidal epithelial cells in alveolar tubules contained conspicuous glycogen deposits, and differentiation of alveolar type II cells was adversely affected. These results suggest that prenatal exposure to methylmercury may be detrimental to lung development, specifically to the initiation of surfactant synthesis, by delaying the normal pattern of maturation of the alveolar type II cells within the lungs. Pediatr Pulmonol. 1994; 17:11–21. © 1994 Wiley‐Liss. Inc.
Use of BiPAP® by nasal mask in the treatment of respiratory insufficiency in pediatric patients: Preliminary investigation
Authors: Padman Raj , Lawless Stephen , Von Nessen Susan
Published: March 2007

A device for nasally applied bilevel positive airway pressure, BiPAP® (Respironics Inc., Murrysville, PA), is currently being evaluated for the treatment of respiratory failure in pediatric and adult patients. This retrospective case review examines our experience with using BiPAP in the treatment of acute ventilatory deterioration in pediatric patients with chronic respiratory insufficiency. All patients who presented to the intensive care unit with chronic respiratory insufficiency and ventilatory failure but without hypoxia were given a trial on BiPAP. Fifteen patients, ages 4–21 years, received such ventilatory support. Four of them had cystic fibrosis (CF) and 11 had neuromuscular disease (2, spinal muscular atrophy; 7, Duchenne muscular dystrophy; 1, spinal cord injury; and 1, myopathy of undetermined origin). Hospital days, respiratory rates, resting heart rates, arterial blood gases, serum bicarbonates, and subjective assessment by parents and or patients of dyspnea, sleep pattern, and activity tolerance were compared prior to and after initiation of BiPAP. Patients were followed from 1 day to 21 months. In 14 of 15 patients placement of an artificial airway could be avoided. Significant decreases in hospital days, respiratory rate, heart rate, serum bicarbonate, and arterial P were observed after initiation of BiPAP. Decline in dyspnea (87% with severe distress at rest prior vs. 80% comfortable at rest after BiPAP), increased activity tolerance (57% attending school after BiPAP vs. none prior to BiPAP), and improved quality of sleep (93% with cornfortable sleep, no daytime somnolence vs. none with comfortable sleep and 36% with daytime somnolence prior to BiPAP). After initiation of BiPAP, all patients were managed outside of the intensive care unit and hospital days declined or, in 4 patients with CF, lung transplantation was done. No major complications occurred. Bilevel positive airway pressure appears to be a promising, safe, noninvasive modality for the treatment of acute and/or chronic respiratory failure in pediatric patients with chronic respiratory diseases. Pediatr Pulmonol. 1994; 17:119–123. © 1994 Wiley‐Liss, Inc.
Disseminated aspergillosis in a patient with cystic fibrosis and allergic bronchopulmonary aspergillosis
Authors: Chung Youngran , Kraut Jerome R. , Stone Arvey M. , Valaitis Jonas
Published: March 2007

Allergic bronchopulmonary aspergillosis (ABPA) is a, well‐known complication of cysticfibrosis (CF), with an estimated incidence of up to 11%. In patients with CF, the diagnosis of ABPA must be based on significant elevation of Aspergillus fumigatus (Af) antibody and total serum IgE, since it is common to already have other clinical and laboratory features of ABPA (Laufer et al., J Allergy Clin Immunol. 1984; 73:44–48). Once ABPA is identified in a patient, institution of corticosteroids is standard therapy.

Invasive aspergillosis is a rare occurrence in patients with CF with or without ABPA, and has been reported in only one young adult who did not have ABPA (Giudotti et al., Am J Med Sci. 1982; 283:157–160). We present a case of a 15‐year‐old male with CF and ABPA who developed disseminated aspergillosis. Pediatr Pulmonol. 1994; 17:131–134. © 1994 Wiley‐Liss, Inc.
Influence of head‐neck posture on airflow and pulmonary mechanics in preterm neonates
Authors: Reiterer F. , Abbasi Soraya , Bhutani Vinod K.
Published: March 2007

The influence of head‐neck posture (neutral, 15°, 30°, and 45° extension and flexion) on airflow and pulmonary mechanics was evaluated in 10 spontaneously breathing healthy preterm neonates (mean ± SD; birth weight, 1.32 ± 0.23 kg; gestational age, 29.4 ± 2.4 weeks; study age, 36.6 ± 1.6 weeks) who had had respiratory distress syndrome. Head‐neck postures were quantified using specially constructed wooden wedges. Airflow was measured by a pneumotachometer via face mask. Lung compliance (CL) and resistance (RL) were measured using an esophageal balloon. Airflow interruption was designated as mild (10–40%), moderate (40–80%), and severe (>80–00%) decrease of airflow. At neutral head‐neck posture, 42.8 ± 7.5% SEM of breaths had airflow interruption (71.4% mild, 19.9% moderate, 8.7% severe). There was no significant change with 15° and 30° head‐neck flexion and extension. However, at 45° flexion the overall incidence of airflow interruption (77.3 ± 4.8%, P < 0.05) and R, (86.6 ± 6.7 vs. 64.2 ± 3.9 cmH2O/L/s, mean ± SEM; P < 0.05) significantly increased. Extension to 45° caused severe airflow interruption and increased RL in some infants, but no statistically significant change for the whole group. The incidence of severe airflow interruption significantly increased (P < 0.05) from 8.7% at neutral head‐neck posture to 26.3% at hyperflexion (45°). No changes in CL were observed. We conclude that minor (15–30°) deviations from neutral neck posture are insignificant, whereas hyperflexion, and in some infants, hyperextension, can significantly affect airflow and pulmonary mechanics. Pediatr Pulmonol. 1994; 17:149–154. © 1994 Wiley‐Liss, Inc.
Pulmonary mechanics during respiratory distress syndrome in the prediction of outcome and differentiation of mild and severe bronchopulmonary dysplasia
Authors: van Lierde S. , Smith J. , Devlieger H. , Eggermont E.
Published: March 2007

Pulmonary mechanics was prospectively and longitudinally studied in a cohort of 58 infants who suffered from respiratory distress syndrome. The aim was to determine if early compliance and resistance measurements had additional value to simple clinical variables in predicting poor outcome ie nonsurvival or severe bronchopulmonary dysplasia (BPD) at 28 days. Second, we wanted to determine whether and when the recently described type 1 (mild) BPD and type 2 (severe) BPD could be differentiated by means of lung function tests. In a logistic model, neither lung Compliance nor pulmonary resistance at days 1 and 4 of life were selected as predictive variables. On the other hand, gestational age and the ventilatory index no. 1 (ventilator frequency × maximal inspiratory pressure) on day 3 were the best early predictors of poor outcome. Type 2 BPD was characterized by a lower lung compliance and a higher pulmonary resistance than type 1 BPD, although the differences were only significant at 28 days. In conclusion, pulmonary function tests were not helpful in the early prediction of poor outcome at 28 days. They might, however, be of value in the follow‐up of BPD patients after 28 days. Pediatr Pulmonol. 1994; 17:218–224. © 1994 Wiley‐Liss, Inc.
Are tidal breathing indices useful in infant bronchial challenge tests?
Authors: Aston Hazel , Clarke Jane , Silverman Michael
Published: March 2007

Tidal breathing indices have been used to assess histamine‐induced airway obstruction in adults and children. The aim of this study was to see whether they could be used to assess histamine challenge in infants. Tidal flow during quiet breathing was measured using a face mask and pneumotachograph and maximum flow at functional residual capacity (VmaxFRC) was measured from partial forced expirations in 18 sleeping, sedated infants who responded to histamine challenge and in 18 nonresponders. The tidal indices calculated were inspiratory and expiratory time (t1, and te), tidal peak expiratory flow (PEF), mean tidal expiratory flow rate (VT/te) and the expiratory time constant of the respiratory system (trs). The time to maximal expiration divided by expiratory time (tme/te) and 2 revised forms of this index (tme(a)te and tme(b)( tme(b) /te) were also calculated. Recordings of tme(a) and tme(b) were taken at 95% of peak tidal expiratory flow, before and after the peak, respectively. In nonresponders, there was an insignificant mean rise in VmaxFRC of 11.8% but no change in any tidal index. In responders, the mean percentage fall in VmaxFRC was 43.3% (range, −31 to −81%); trs fell from 0.61 s to 0.51 s (P < 0.05) and breathing frequency and mean tidal expiratory flow rate increased from 34.0 to 37.5 min−1 (P < 0.01) and from 66.6 to 72.6 mL.s−1 (P < 0.05), respectively, suggesting that infants had adopted a strategy of active expiration in response to bronchial challenge. There was no change either in tme/te, or in the revised indices after challenge., It is therefore concluded that tme/te is an insensitive index of airflow obstruction compared to VmaxFRC and cannot be used to assess the response to bronchial challenge. Changes in other indices were small and related to a presumed pattern of active expiration after challenge. Pediatr Pulmonol. 1994; 17:225–230. © 1994 Wiley‐Liss, Inc.
Decrease in the airways' nonadrenergic noncholinergic inhibitory system in allergen sensitized rabbits
Authors: Fame Thomas M. , Colasurdo Giuseppe N. , Loader Joan E. , Graves Juanita P. , Larsen Gary L.
Published: March 2007

A decrease in the airways' nonadrenergic noncholinergic inhibitory (NANC‐i) system is one of the mechanisms that may contribute to allergen‐induced changes in neural control within airways. We measured the airways' neurally mediated contractile and relaxant (NANC‐i) responses in tracheal segments and left mainstem bronchus (LMB) from normal (control), immune (ragweed sensitized), and immune challenged rabbits. Immune rabbits were sensitized to mixed ragweed extract through parenteral injections from birth, while the immune challenged group had an additional airway exposure to aerosolized ragweed 48 hours prior to the in vitro studies. Neurally mediated contractile responses to electrical field stimulation (EFS) were increased in the immune challenged group, with the increase most significant in tracheal smooth muscle at a stimulation frequency of 20 Hz. To assess NANC‐i responses, airway smooth muscle (ASM) segments from these groups were placed in tissue baths containing atropine (10−6 M) and propranolol (5 × 10−6 M). After contraction of the tissue with neurokinin A (NKA, 10−5 M), the NANC‐i response to EFS at 20 Hz was measured and reported as the mean (± SEM) percent relaxation. No significant differences were seen in the contractile responses of ASM segments to NKA among the three groups. The tracheal segments showed a significantly different NANC‐i relaxation response among all groups: in the control group, 29.1 ± 3.7; in the immune group 15.8 ± 2.3%; and in the immune challenged group, 2.1 ± 4.2%. The LMB segments showed significantly different NANC‐i responses between the immune challenged group (M−3.4 ± 2.5%) and both the control (13.4 ± 5.7%) and immune group (9.5 ± 2.9%). This NANC‐i response was not diminished by the nitric oxide synthase inhibitor NG‐nitro‐L‐arginine methyl ester (10−4 M). We conclude the exposure to ragweed through the airways in rabbits with IgE to this allergen leads to an enhanced contractile response to EFS and a significant decrease in the airways' NANC‐i response when compared with normal or immune rabbit airways. In addition, a significant decrease in NANC‐i response occurs in tracheal segments from rabbits after parenteral ragweed immunization alone. This decrease in NANC‐i may be one mechanism contributing to the altered airway responsiveness associated with IgE immune states. Pediatr Pulmonol. 1994; 17:296–303. © 1994 Wiley‐Liss, Inc.
High altitude climate therapy reduces peripheral blood T lymphocyte activation, eosinophilia, and bronchial obstruction in children with house‐dust mite allergic asthma
Authors: Simon Hans‐Uwe , Grotzer Michael , Nikolaizik Wilfried Helmut , Blaser Kurt , Schöni Martin H.
Published: March 2007

Asthma is a multifactorial disease of unknown etiology but often associated with atopy and inflammation. Previous studies in adult asthma have demonstrated the presence of activated T cells in blood, bronchoalveolar lavage (BAL) fluid, and bronchial tissue, and the relevance of their soluble products for eosinophil function. In view of these observations, it was hypothesized that similar pathogenetic mechanisms also occur in childhood asthma. In fact, peripheral blood T lymphocytes in 14 children with house‐dust mite allergic asthma showed clear evidence of T cell activation as measured by the expression of CD25 and HLA‐DR antigen. Without changing medication, significant reduction of the IL‐2 receptor a‐chain expression within the CD4+ lymphocyte population was observed after only 3 weeks of allergen avoidance. Within this time period, absolute and relative eosinophil numbers decreased to normal levels. After 5 weeks in an area of low house‐dust mite exposure, lung function also presented evidence for clinical improvement of the asthmatic disease. These results indicate similar pathogenetic mechanisms in childhood and adult asthma. Furthermore, they suggest that allergen avoidance may contribute to the efficient therapy of asthma in patients with house‐dust mite IgE‐meditated allergy. Pediatr Pulmonol. 1994; 17:304–311. © 1994 Wiley‐Liss, Inc.