bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of nasal impedance using the forced oscillation technique in infants
Authors: Desager K. N. , Willemen M. , van Bever H. P. , de Backer W. , Vermeire P. A. 
Published: March 2007

AbstractBy applying oscillations to the respiratory system through a rigid face mask, the infant‐adapted Lándsér forced oscillation technique measures impedance of the total respiratory system including the nose, at frequencies from 4 to 52 Hz. The present study was aimed at evaluating nasal impedance in infants from consecutive forced oscillation measurements through both nostrils and each nostril separately, using a simple electrical model. In 30 asthmatic infants with varying degrees of nasal obstruction, aged 1–16 months, calculated nasal resistance (Rn) at 24 Hz ranged from 1 to 16 cm H2O · L−1 · s. The ratio of Rn to total respiratory system resistance varied between 1 and 48% (mean: 16%). In seven non‐asthmatic infants, aged 0‐12 months, Rn was between 1 and 11 cm H2O · L−1 · s. Nasal patency (evaluated clinically) was correlated with the calculated Rn (P < 0.05). Rn showed almost no frequency dependence between 24 and 48 Hz as demonstrated by a mean slope of −0.09 ± 0.08 cm H2O · s2/L for the asthmatic and of −0.08 ± 0.07 for the non‐asthmatic infants. In seven of the asthmatic infants the differences between two Rn determinations at a 45 min interval ranged from −1.7 to 3.8 cm H2O · L−1 · s−1 at 24 Hz and from −3.6 to 1.0 at 48 Hz. Changes in Rn did not correlate with changes in total respiratory system resistance (P > 0.05). In conclusion, nasal impedance can be approximated from three consecutive measurements through both nostrils and through each nostril separately.Pediatr Pulmonol. 1991 ; 11 :1‐7.
Pulmonary function in newborns after repair of congenital diaphragmatic hernia
Authors: Nakayama Don K. , Motoyama Etsuro K. , Mutich Rebecca L. , Koumbourlis Anastassios C. 
Published: March 2007

AbstractCongenital diaphragmatic hernia (CDH) is associated with pulmonary hypoplasia that limits survival, but the nature and extent of pulmonary dysfunction in neonates with CDH have not been studied. We performed pulmonary function tests (PFTs) in eight intubated infants who survived neonatal repair of CDH (wt, 3.33 ± 0.15 kg; age, 20.1 ± 2.7 d; mean ± S.E.M.). PFTs obtained from six full‐term infants (wt, 3.56 ± 0.10 kg; age, 25.0 ± 3.3 d) with no respiratory illness served as controls. The deflation flow‐volume curve technique produced maximum expiratory flow‐volume (MEFV) curves, giving reproducible measurements of forced vital capacity (FVC) and maximal expiratory flow at 25% of FVC (MEF25). Respiratory system compliance (Crs) and resistance (Rrs) were obtained with a modified passive mechanics technique. In seven of eight infants PFTs were repeated after nebulized bronchodilator (0.1% isoetharine). In neonates surviving CDH repair, as compared to those with normal lung function, FVC was significantly reduced (20.78 ± 3.32 vs. 39.83 ± 3.30 mL · kg−1, P < 0.05). MEF25 was also markedly reduced (8.41 ± 1.46 vs. 32.32 ± 4.35 mL · kg−1 · s−1, P < 0.05), indicating lower airway obstruction. After administration of nebulized bronchodilator, PFTs showed significant increases from control values in both FVC (15.9%) and MEF25 (200%) without changes in Crs and Rrs. These findings indicate that neonates with CDH have restrictive lung defects, reflecting hypoplasia. After surgical repair and mechanical ventilation airway reactivity develops, primarily in smaller airways, and this may complicate the postoperative course. Pediatr Pulmonol. 1991 ; 11 :49‐55.
Respiratory responses of piglets to hypercapnia during postnatal development: Effects of opioids
Authors: Segal B. Scott , Inman Jamie D. G. , Moss Immanuela R. 
Published: March 2007

AbstractResting respiratory and cardiovascular functions and the response to CO2 rebreathing were compared between 2.5 ± 0.7 (mean ± SE) and 34.1 ± 1.9 day old piglets, before and after the opioid antagonist naltrexone (1 mg/kg IV). At rest, tidal volume, both absolute and per m2, inspiratory and expiratory time, absolute minute ventilation, and mean arterial pressure increased with age, and breathing frequency, minute ventilation per m2, and heart rate decreased, all of these with as well as without naltrexone. During hypercapnia, the pattern, but not the quantitative aspects of breathing changed with age.At rest, naltrexone produced hyperventilation in the young, but not in the older group. During hypercapnia, naltrexone had a sparse effect in both ages.We conclude that, in the anesthetized piglet, ventilatory functions at rest undergo change with postnatal age, but breathing responses to hypercapnia exhibit maturation in pattern only and not in magnitude. Whereas resting ventilation of young piglets is modulated by endogenous opioids, hypercapnia may activate opioids to a limited extent and in a manner unrelated to age.
Regional cycles of perfusion and non‐perfusion in the lung of the term fetal rabbit
Authors: Lipsett Jill , Gannon Bren 
Published: March 2007

AbstractThe spatial distribution of pulmonary blood flow and its change over time was investigated in term fetal rabbits, using the plasma tracer fluorescein‐isothiocyanate‐labeled bovine serum albumin (FITC‐BSA). A tracer bolus was injected intravenously and allowed to circulate in vivo for increasing periods of time (2–30 minutes) prior to arrest of the circulation and tissue preparation.Initially, fluorescence was present in the vasculature of 43% of lung parenchymal tissue, disposed as discrete regions or “lobules.” Interspersed regions of lung tissue received no tracer inflow. With increasing tracer circulation times (10, 20, and 30 minutes), a greater percentage of lung cross‐sectional area contained vessels exhibiting tracer fluorescence (64, 96, and 100%, respectively).In the fetal lung, a high pulmonary vascular resistance (PVR) is maintained. Our studies indicate that, at any given moment, fetal pulmonary blood flow is distributed only to a proportion of discrete lung “lobules,” while interspersed “lobules” receive no flow at all. The “lobules” alternate between these “high” and “low” vascular resistance states with a periodicity of approximately 35 minutes, comprising 22 minutes of non‐perfusion followed by 13 minutes of perfusion.This circulatory pattern permits both the maintenance of high PVR and uniform lung development. Further, by directing flow to only a portion of the vasculature, greater microvascular flow rates are achieved and hence the risk of blood sludging and stasis is reduced. Recruitment of these “non‐perfused” regions at birth could thus produce a significant reduction in PVR.
Effects of a clinically detectable PDA on pulmonary mechanics measures in VLBW infants with RDS
Authors: Balsan Michael J. , Jones Judith G. , Guthrie Robert D. 
Published: March 2007

AbstractWe examined the effect of a clinically detectable patent ductus arteriosus (PDA) and its successful treatment with indomethacin on serial measures of pulmonary mechanics in 10 very‐low‐birthweight (VLBW) intubated infants with respiratory distress syndrome (RDS). Pulmonary mechanics were measured by the passive expiratory flow technique. Total respiratory system compliance (Crs) gradually improved as RDS resolved. However, a significant decrease in mean Crs was associated with the development of a clinically detectable PDA, ranging from 1.51 ± 0.21 to 0.90 ± 0.08 mL/cmH2O/m (P < 0.05). We also noted an increase in mean Crs, from 0.90 ± 0.08 to 1.49 ± 0.21 mL/cmH2O/m (P < 0.05), after successful treatment of a PDA with indomethacin. Total respiratory system resistance (Rrs) did not change. We conclude that a clinically significant PDA is associated with a decreased Crs and that successful treatment of a PDA with indomethacin is associated with an improvement in lung compliance. These findings imply that the development of a clinically detectable PDA and its subsequent treatment complicates the interpretation of pulmonary mechanics data in VLBW infants with RDS.
Hyperinflation in children with liver disease due to alpha‐1‐antitrypsin deficiency
Authors: Hird M. F. , Greenough A. , Mieli‐Vergani G. , Mowat A. P. 
Published: March 2007

AbstractFifty‐nine patients (median age 6.0 years) with liver disease and ten healthy children without liver disease (median age 7.5 years) had serial measurements of functional residual capacity (FRC) over a period of at least 6 months. Twenty‐eight children with alpha‐1‐antitrypsin deficiency (A1ATD) tended to have higher lung volumes than 26 with extrahepatic biliary atresia (EHBA). Fifteen children had persistent hyperinflation (FRC > 120% predicted for height; 2 SD above the mean of controls); in five children (four with A1ATD) this was unresponsive to bronchodilator therapy. Two of the children with A1ATD who had persistent unresponsive hyperinflation on three serial measurements were only 3 and 4 years of age. No healthy child without liver disease was hyperinflated. These results suggest that A1ATD may be associated with lung function abnormalities even in very young children.
Psychological change associated with theophylline treatment of asthmatic children: A 6‐month study
Authors: Bender Bruce G. , Lerner Joey A. , Ikle David , Comer Carolyn , Szefler Stanley 
Published: March 2007

AbstractTheophylline has been associated with a variety of behavioral side effects in asthmatic children. This study was a 6‐month investigation of the relationship between theophylline treatment and psychological changes in 8 to 16 year old asthmatic children. Included were a group receiving theophylline (n = 19), a control group not receiving theophylline (n = 44), and a nonasthmatic control group (n = 24). The three groups had similar age, socioeconomic status, and IQ. The two groups of children with asthma demonstrated greater emotional dysfunction, characterized by tendency toward withdrawal and depression, than the nonasthmatic control group. Each of five assessment appointments (baseline and 1 week, 1 month, 3 months, and 6 months after beginning theophylline treatment) included measures of pulmonary function, attention, impulsivity, memory, fine motor control, activity level, self‐reported mood, and parental observation of difficult behavior. Pulmonary functions were lower in the theophylline group at baseline but improved significantly after commencement of theophylline therapy. Over the 6‐month interval, children in the theophylline group demonstrated improved scores on a laboratory measure of attention, while their parents reported increased conduct problems and hyperactivity. On the whole, psychological score changes were subtle, and no other betweengroup differences emerged in the remaining laboratory measures.
Respiratory mechanics of the piglet during the first month of life
Authors: Standaert Thomas A. , Wilham Bruce E. , Mayock Dennis E. , Watchko Jon F. , Gibson Ronald L. , Woodrum David E. 
Published: March 2007

AbstractPiglets at 3, 14, and 30 days of age were studied to assess the postnatal changes in lung, chestwall, and total respiratory system compliance associated with normal growth. Static deflation compliance of the lung and total respiratory system increased significantly with age; there was no change in chestwall compliance. When normalized for body weight or lung volume, all measures of compliance tended to decrease with postnatal age. Measures of lung and chestwall compliance obtained with an end‐inspiratory occlusion technique were less than the static compliance measures, but demonstrated the same relative changes with postnatal maturation. Chestwall compliance at 3 days of age was only 1.3 times greater than lung compliance and there was no significant change in this ratio with postnatal age. In contrast to the trend for the human infant,1 the piglet's chestwall at 3 days of age is stiff relative to the lung and does not become stiffer with age over the first 4 weeks of life.
The effect of intravascular complement activation and brief episodes of hypoxia on protein in bronchoalveolar lavage fluid in C5 sufficient and deficient mice
Authors: Larsen Gary L. , Presley Debra M. , Graves Juanita P. , Giclas Patricia C. 
Published: March 2007

AbstractOur earlier investigations indicated that systemic complement activation with iv cobra venom factor (CVF) or infused zymosan‐activated rabbit plasma or rabbit C5a does not significantly increase bronchoalveolar lavage albumin in rabbits (Am Rev Respir Dis 1982; 125:335–340); but that complement activation due to CVF combined with a brief episode of hypoxia increases lavage albumin and is associated with the presence of neutrophils for its expression (J Clin Invest 1985; 75:902–910). In order to determine if intravenous CVF and hypoxia cause similar alterations in mice, and to investigate the time course of the response as well as the importance of C5 fragments to the process, we challenged the B10.D2/oSn strain of C5 sufficient mice (C5+) and the congenic B10.D2/oSn strain of C5 deficient mice (C5−) with intravenous CVF, 15 min of 12% oxygen, or CVF followed by hypoxia. Neither C5+ nor C5− mice had significant increases in lavage protein after either CVF or hypoxia. However, the combined insults significantly increased lavage protein in C5+ but not C5− mice; polyacrylamide gel electrophoresis showed increased amounts of proteins of low and high molecular weights in lavage fluid from the C5+ strain. While the time course of abnormalities in mice was different from that in rabbits, both meclofenamate pretreatment and neutrophil depletion attenuated the increases in lavage protein after the combined insults in both animal species. Infusion of prostaglandin E2 (PGE2) with CVF in the C5+ mice also led to significant increases in lavage protein. We conclude that in mice, intravenous complement activation, as an isolated event, does not cause a significant increase in lavage protein. However, combining complement activation with another stimulus (hypoxia or intravenous PGE2) leads to significant increases in protein accumulation in the lung. With CVF and hypoxia in this system, the presence of neutrophils, the fifth component of complement, and an intact cyclooxygenase pathway of arachidonic acid metabolism may be necessary to produce an increase in lavage protein.
Hering‐breuer reflex in young asthmatic children
Authors: Greenough A. , Pool J. 
Published: March 2007

AbstractThe aim of this study was to assess if the Hering‐Breuer reflex could be provoked in young children. Thirty asthmatic children with a mean age of 5.3 years and 18 healthy children with a mean age of 7.0 years were studied. The presence of the reflex was indicated by prolongation of the spontaneous expiratory time following application of continuous positive airways pressure (CPAP). The occurrence of the reflex was then related to age, compliance of the respiratory system (Crs) measured by weighted spirometry, functional residual capacity (FRC) determined by helium gas dilution, and the change in lung volume resulting from the application of CPAP. The asthmatic children in whom the Hering‐Breuer reflex was observed tended to be younger (P < 0.01) and the reflex was present in those children of both groups who had more compliant lungs (P < 0.05). The FRC was not different in asthmatic children with and without the Hering‐Breuer reflex, but healthy children in whom the reflex was present tended to have smaller lung volumes. The change in lung volume resulting from application of CPAP was significantly greater in those children of both groups in whom the reflex was present (P < 0.01 asthmatics, P < 0.02 healthy children). We conclude that the Hering‐Breuer reflex may be provoked in young children.
Optimal electrode location for monitoring the ECG and breathing in neonates
Authors: Baird Terry M. , Goydos Janie M. , Neuman Michael R. 
Published: March 2007

AbstractContinuous monitoring of breathing in infants is commonly performed using transthoracic impedance. This method employs skin surface electrodes measuring changes in electrical impedance and relates these changes to respiratory events. Typically, two electrodes on the infant's chest monitor both the ECG and breathing. We have attempted to identify separate electrode locations that give the best signal for breathing and ECG, and a single location that optimizes both of these signals. Thirty‐seven infants were studied by placing 12 electrodes on the infant's chest and abdomen, and serially sampling pairwise combinations of electrodes. The optimal signal for breathing was obtained when electrodes spanned the diaphragm. Optimal ECG signal was seen with one electrode at the right mid‐clavicle and one at the xyphoid. Clinicians should be aware of these locations in order to provide the best signal available.
Correcting for the Bernoulli effect in lateral pressure measurements
Authors: Bates J. H. T. , Sly P. D. , Sato J. , Davey B. L. K. , Suki B. 
Published: March 2007

AbstractMeasurement of airway pressure is essential in the study of respiratory mechanics, and is usually done via a lateral tap in the conduit (e.g., endotracheal tube, cannula, or mouth‐piece) leading into the subject's airway. Such pressure measurements, however, may be severely affected by the Bernoulli effect if the diameter of the conduit is small and the gas flow through it sufficiently high. We present in this note a simple method of assessing whether or not the Bernoulli effect is important in any particular situation. The technique involves comparing the pressure‐flow relationships of the conduit obtained both by blowing air through it from one end and sucking air in the reverse direction by applying negative pressure at the same end. If the resistance of the conduit is the same for gas flow in both directions, then half the magnitude of the difference between the two pressure‐flow relationships gives the magnitude of the Bernoulli effect pressure. We give results of an experimental situation in which this was the case. We also show that those conditions under which the Bernoulli effect is likely to be a problem are also those under which the velocity profile is likely to be approximately flat, thereby permitting the magnitude of the Bernoulli effect to be easily calculated.
A radiographic method for estimating lung volumes in sick infants
Authors: Fumey Marie‐Hélène , Nickerson Bruce G. , Birch Martha , McCrea Ray , Kao Lily C. 
Published: March 2007

AbstractEstimation of lung volumes by conventional methods in sick infants is technically difficult and is the subject of controversy. In this study, we compared both thoracic gas volume (TGV), measured with an infant whole body plethysmograph, and functional residual capacity (FRC), determined by the nitrogen washout technique, to planimetric measurements of anteroposterior chest radiographs in 26 infants with bronchopulmonary dysplasia (BPD). © 1992 Wiley‐Liss, Inc.The tidal volume (TV) of each patient was added to TGV and FRC because these were measured at the end of expiration whereas chest radiographs were taken at the end of spontaneous inspiration. The regression equations expressing the relationships between TGV and right + left lung field areas [A + B], and between FRC and lung areas are expressed as follows: [TGV + TV](mL) = 3.3 mL/cm2 × [A + B] cm2 + 24 mL and [FRC + TV](mL) = 3.5 mL/cm2 × [A + B] cm2 − 13.5 mL. Correlation coefficients of 0.9 and 0.7 for TGV and FRC, respectively, suggest a stronger correlation between TGV and lung areas than between FRC and lung areas.Lung areas measured by planimetry correlate closely with physiological measurement of lung volumes. We conclude that the planimetric method is an inexpensive and reliable technique for estimating lung volumes in young infants with BPD when chest radiographs are available.
Partial and massive lung lavages in an infant with severe pulmonary alveolar proteinosis
Authors: Mahut B. , de Blic J. , le Bourgeois M. , Beringer A. , Chevalier J. Y. , Scheinmann P. 
Published: March 2007

AbstractPulmonary alveolar proteinosis is a rare disease of unknown etiology, characterized by progressive respiratory failure. Lung lavage has only been applied in a few children. A 6 month old boy suffering from severe pulmonary alveolar proteinosis was treated with three lung lavages. The first two were partial (or unilateral) lavages; a 3.5 mm flexible bronchoscope was introduced adjacent to a no. 3 cuffed endotracheal tube. This procedure allowed selective ventilation of one lung, and contralateral lung lavage. Respiratory improvement was observed during 1 week after the two procedures. At the third lavage we used partial veno‐venous extracorporeal circulation because of severe respiratory failure. A significant improvement during the 5 following months was achieved. These results suggest that both partial and total lung lavage can be performed even in young infants and they may control the declining respiratory status in severe pulmonary alveolar proteinosis. © 1992 Wiley‐Liss, Inc.
Dissociation of symptom scores and bronchial hyperreactivity: Study in asthmatic children on long‐term treatment with inhaled beclomethasone dipropionate
Authors: Benoist Marie R. , Brouard Jean J. , Rufin Patrick , Waernessyckle Serge , de Blic Jacques , Paupe Jean , Scheinmann Pierre 
Published: March 2007

AbstractThe aim of the study was to evaluate the effects of inhaled steroids (IS) on the improvement of clinical asthma symptoms and on the decrease in bronchial hyperreactivity (BHR). Twenty‐four children with severe asthma were given 1,000 μg beclomethasone dipropionate (BDP) daily and compared with ten asthmatic control children. The study included the evaluation of daily clinical score, of exercise induced asthma, of bronchial obstruction (forced expiratory volume in 1 sec, FEV1), and of BHR at months 0, 1, 2–3, and 4–5 (MO, M1, M2–3, and M4–5) BHR was assessed by standardized inhaled carbachol provocation measuring plethys‐mographic specific airway resistance (SRaw). The carbachol dose causing a 40% decrease in specific conductance (SGaw) was determined (PD40 SGaw). © 1992 Wiley‐Liss, Inc.Clinical scores decreased at M1 (P < 0.01) and throughout the study. FEV1 increased at M1 (P < 0.05), M2‐3 (P < 0.01), and M4‐5 (P < 0.05) compared to MO. PD40 SGaw only increased significantly at M1 and M2‐3.No individual correlation was found between clinical scores and PD40 SGaw at any testing, or between the decrease of clinical scores and the decrease of BHR.We conclude that bronchoconstrictive challenge tests do not adequately assess the clinical efficacy of IS. In clinical practice non‐specific BHR should be preferentially measured for diagnosing atypical forms of asthma.
Clinical characteristics of parainfluenza virus infection in hospitalized children
Authors: Heidemann Sabrina M. 
Published: March 2007

AbstractSeverity of illness and clinical characteristics of parainfluenza virus (PIV) infection were evaluated in 81 hospitalized children over a 4 year period. Fifty three patients were previously healthy and 28 had preexisting pulmonary abnormalities associated with bronchopulmonary dysplasia (BPD), congenital heart disease (CHD), asthma, or prematurity. When compared with formerly healthy children, the patients with preexisting pulmonary abnormalities were more likely to develop lower than upper respiratory tract illness (P < 0.0001). In the lower respiratory tract infection group, patients with preexisting pulmonary abnormalities were sicker (P = 0.047), were hospitalized longer (P = 0.016), required more supplemental oxygen (P = 0.004), and were older (8.8 vs. 5.1 months) than previously healthy patients. Nosocomial infection occurred only in BPD patients. All these patients developed pneumonia. They were sicker (P = 0.0018), requiring more therapy (P 0.0038) than other patients with preexisting pulmonary abnormalities and lower respiratory tract disease. Patients with BPD should be placed in protective isolation during PIV epidemics. © 1992 Wiley‐Liss, Inc.