bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased physiological dead space during exercise after bronchodilation in cystic fibrosis.
Authors: Kusenbach G. , Friedrichs F. , Skopnik H. , Heimann G.
Published: March 2007

Bicycle ergospirometry was performed on 14 patients with cystic fibrosis (CF), for evaluating the effects of salbutamol and theophylline on the ventilatory response to exercise. After 1 week without bronchodilator therapy the patients cycled at 1/3 and 2/3 of their individual maximal working capacity (Wmax). The test was repeated three times after treatment with salbutamol, theophylline, or both drugs, respectively. After the combined therapy, physiological deadspace, ventilation, ventilatory equivalent of oxygen, and end‐expiratory oxygen pressure increased significantly during steady state exercise at 1/3 Wmax. Similar, although not statistically significant changes, were observed after monotherapy with salbutarnol or theophylline and during exercise at 2/3 Wmax. These effects could not be predicted by any lung function tests at rest or by the Shwachman‐Kulczycki score. The results indicate that in some patients with CF bronchodilators can impair lung function during exercise. In conclusion the effects of medication on exercise performance of patients with CF have to be considered. Especially, the use of bronchodilators requires a careful evaluation of their real benefit in each individual patient. © 1993 Wiley‐Liss, Inc.
Assessment of passive respiratory compliance in healthy preterm infants: A critical evaluation
Authors: Gappa M. , Rabbette P. S. , Costeloe K. L. , Stocks J.
Published: March 2007

The airway occlusion techniques for assessing passive respiratory mechanics have become well established methods in fullterm neonates and older infants. The single breath technique (SBT) is frequently used for assessing lung function in intubated infants on neonatal intensive care units. However, less is known about the reliability of these quick and noninvasive techniques in healthy preterm infants. The aim of this study was to evaluate these methods in healthy unintubated preterm infants to facilitate both establishment of reference values and more meaningful interpretation of lung function assessments in the neonatal unit. Forty‐seven studies were attempted in 31 healthy preterm infants (gestational age 29–36 weeks; body weight 1.88 ± 0.28 kg; mean ± SD) during the first 2 weeks of life, using both the multiple occlusion technique (MOT) and the SBT. Whereas technically acceptable respiratory system compliance (Crs) data from either the MOT or the SBT were obtained on 37 occasions in 25 infants, satisfactory results from both techniques were achieved only on 22 occasions. In these infants mean ± SD Crs was 28.1± 5.2 mL kPa−1 when assessed by MOT and 29.1± 5 6.0 mL kPa−1 when using the SBT. The mean difference between technically satisfactory paired Crs values obtained with MOT and SBT was less than 5% (range, +28 to −18%). By contrast, in infants in whom data were invalidated as a result of expiratory airflow braking, failure to relax or instability of the end‐expiratory level, gross discrepancies occurred between the techniques. In conclusion, assessment of passive respiratory compliance is feasible in healthy, unintubated preterm infants, but strict criteria for quality control should be applied to avoid gross errors in the results. Ideally, passive respiratory mechanics should be assessed using both MOT and SBT in order to increase confidence in the reported results. © 1993 Wiley‐Liss, Inc.
Prognostic value of clinical and radiological status on day 28 of life for subsequent course in very low birthweight (< 1,500g) babies with bronchopulmonary dysplasia
Authors: Hansen Thor W. R. , Wallach Michael , Dey Achintya N. , Boivin Paul , Vohr Betty , Oh William
Published: March 2007

To test the hypothesis that the shortn‐term (= 6 months) course of babies with bronchopulmonary dysplasia (BPD) could be predicted from the clinical and radiological status on day 28 of life, we retrospectively examined the medical records of 79 infants born between 1985 and 1988 who required supplemental oxygen and/or ventilatory support on day 28. Chest roentgenographs taken close to day 28 (± 7 days) were scored on a scale of 0–10. Four babies died from causes not related to BPD. Four of the remaining 75 died from BPD, and the rest are alive. Forty‐six of 71 were weaned from supplementary oxygen by 37 weeks corrected gestational age, and only 13/71 remained on supplemental oxygen after 40 weeks gestational age. To determine which variables contributed most to the outcome, defined as total days on supplemental oxygen, a multiple regression analysis was performed, including only those variables the tolerance of which exceeded 0.7 (sex, Fi, ventilatory mode, and infectious status). Fi, and ventilatory mode together predicted 15% of the variability in outcome, so that a high Fi, and ventilator dependence on day 28 of life were highly correlated with a prolonged need for supple‐mental oxygen (F = 4.28, P < 0.05). © 1993 Wiley‐Liss, Inc.
Evaluation of cold air challenge data in a population sample using a model of bronchial hyperreactivity and disposition to bronchial obstruction
Authors: Wjst Matthias , Dold Sigrid , Reitmeir Peter , Wulff Andrea , Nicolai Thomas , von Mutius Erika
Published: March 2007

To explore the role of bronchial hyperreactivity and obstruction after cold air challenge, data from a cross‐sectional study of more than 7,000 10‐year‐old children were used. Current knowledge of hyperreactivity is primarily based on pharmacological provocation tests with variable prechallenge flow rates and their decrease relative to baseline. Using forced expiratory volume (FEV) in 1 sec values before and after cold air challenge, however, it is possible to define a subsample of children with predominant hyperreactivity and a subsample with predominant obstruction after challenge. The prevalence of respiratory symptoms and the diagnoses in the two subsamples were compared. The analysis showed that children with bronchial obstruction have nearly the same frequency of respiratory symptoms as those with bronchial hyperreactivity. A combined model of bronchial obstruction and hyperreactivity was, therefore, more predictive of symptoms than a model of hyperreactivity alone. © 1993 Wiley‐Liss, Inc.
Use of pulse oximetry in the hospital management of acute asthma in childhood
Authors: Connett G. J. , Lenney W.
Published: March 2007

Oxyhemoglobin saturation values were recorded before and 10 minutes after 5 mg of nebulized salbutamol in 75 children (age, 1.5–14.6 years) admitted to hospital with acute asthma. Other assessments included heart rate, respiratory rate, peak expiratory flow rate, pulsus paradoxus, and an asthma severity score. All assessments were performed by the same observer (GC) and subsequent hospital care was transferred to the on‐call pediatricians, who were not told the initial saturation values. Six children required intravenous therapy after hospital admission when their symptoms were not improved after nebulized salbutamol. Cutoff points for each continuous variable were selected so that they identified at least 5 of these 6 children (i.e., with a sensitivity of at least 83 percent). The resulting specificities and positive predictive values were calculated for each variable before and after nebulized therapy. A postnebulizer saturation of less than 91 % had a sensitivity of 100% [95% confidence interval (CI), (54–1001 with a specificity of 98%] (95% CI, 92–100) and a positive predictive value of 86%. This was the best predictor of the need for intravenous (IV) therapy. Correlation coefficients were calculated for the 75 admissions and 2 others who required immediate IV treatment to determine how closely saturation values were related to the other recorded clinical variables. Saturation values were significantly, though weakly, correlated with asthma severity scores and prenebulizer heart rate, but they were not associated with any of the other variables. These results highlight the difficulties encountered when assessing acute asthma in a hospital population with a large number of preschool children. Saturation measurements are easy to obtain in all age groups and help identify those children who require intensive therapy and close supervision after hospital admission. © 1993 Wiley‐Liss, Inc.
Relationship between exposure to dust mite allergen and bronchial response to exercise in schoolchildren sensitized to dust mites
Authors: Frischer T. H. , Kuehr J. , Meinert R. , Karmaus W. , Urbanek R.
Published: March 2007

We assessed the relationship between the exposure to dust mite allergens and a bronchial response to exercise in 8‐year‐old schoolchildren. Dust was collected from the mattresses of 1, 291 children and the concentration of mite allergens was estimated by a commercially available ELISA test using monoclonal antibodies (ALK, Copenhagen) against the major allergens of Dermatophagoides pteronyssinus (Der pt) and Dermatophagoides farinae (Der f). A positive bronchial response to exercise (decrease of peak expiratory flow ≥ 5% after exercise) occurred in 21 (22.6%) of 101 children sensitized to mite allergens (wheal size ≥4 mm) and in 51 (4.8%) of 1, 070 nonsensitized children. In the highest exposure groups (>10 μg allergen/g dust), 15% of children sensitized to Der f and 20% of children sensitized to Der pt were responsive to exercise. Corresponding figures for the lowest exposure groups (< 0.4 μg allergen/g dust) were 11 and 28%, respectively. This negative finding may indicate that measurement of allergen concentration in mattresses does not reflect true exposure or alternatively that at the age of 8 years high exposure to dust mite allergens does not affect bronchial response to exercise in sensitized children. Pediatr Pulmonol. 1993; 16:13–18. © Wiley‐Liss, Inc.
Maturation affects the maximal pulmonary response to methacholine in rabbits
Authors: Tepper Robert S. , Kisling Jeff , Brearton Linda
Published: March 2007

Maximal bronchoconstriction in normal adults produces only small reductions in pulmonary function; however, in normal infants severe airway obstruction limits testing to low agonist concentrations. In this study, maximal pulmonary response to methacholine was evaluated in 5 immature (1 month old) and 5 mature (6 months old) rabbits. Animals were anesthetized, paralyzed, and mechanically ventilated via a tracheostomy tube. Changes in pulmonary function were assessed from maximal deflation flow volume curves following inhalation of doubling concentrations of methacholine between 0.6 and 320 mg/mL. Following 320 mg/mL methacholine, the immature rabbits had a greater percent decline in forced vital capacity (FVC) than the mature animals (55 ± 15% vs. 36 ± 10%; P < 0.05). At 50% FVC, isovolume flows were measurable in the 5 mature rabbits, and 4 of 5 had plateaus in their dose‐response curves. At the higher methacholine doses, only 1 of 5 immature animals had measurable isovolume flows because of the decrease in FVC. There was no significant difference between immature and mature animals in the methacholine dose required to decrease baseline flows by 50%. We conclude that in rabbits maturation affects maximal pulmonary response but not the sensitivity to methacholine. Pediatr Pulmonol. 1993; 16:48–53. © 1993 Wiley‐Liss, Inc.
Airway responsiveness in infants: Comparison of inhaled and nasally instilled methacholine
Authors: Tepper Robert S. , Steffan Michael
Published: March 2007

Airway responsiveness of infants is evaluated during sleep and the infants inhale the bronchial challenge agent via the nasal airway. Since stimulation of the nasal airway may produce bronchoconstriction, it is unclear whether the observed response in the infants results from deposition of the aerosol in the lower airways or from stimulation of nasal receptors. Therefore, in 6 healthy infants we compared the changes in partial expiratory flow‐volume (PEFV) curves produced by aerosol inhalation of methacholine and the changes produced by instillation of equivalent doses of methacholine liquid into the nares. Following aerosol, the peak expiratory flow and the flow at functional residual capacity decreased, PEFV curves became concave in shape, and the oxygen saturation (Sao2) decreased. The highest methacholine concentration inhaled by any infant was 1.25 mg/mL. In contrast to aerosol delivery, a maximal methacholine concentration of 10.0 mg/mL was instilled into the nares of all 6 infants without any change in maximal flow at functional respiratory capacity (VmaxFRC) or Sao2. There was a significant decrease in peak flow and flattening of the PEFV curves at higher lung volumes; however, the PEFV curve remained convex in shape at the lower lung volumes. The changes in the PEFV curve following nasal instillation of methacholine are consistent with an increase in nasal resistance and no change in the lower airways. We conclude that the bronchoconstriction observed following inhaled methacholine does not result from stimulation of nasal receptors. Pediatr Pulmonol. 1993; 16:54–58. © 1993 Wiley‐Liss, Inc.
Chest wall motion before and during mechanical ventilation in children with neuromuscular disease
Authors: Diaz Carlos E. , Deoras Kiran S. , Allen Julian L.
Published: March 2007

Patients with neuromuscular disease can display paradoxic motion of the rib cage (RC) and abdomen (AB), which increases the work of breathing and predisposes to respiratory muscle fatigue. Long‐term mechanical ventilation can reverse chronic hypercapnea and decrease the work of breathing in these patients. Changes in chest wall motion (CWM) that occur during mechanical ventilation have not been studied. We have assessed CWM using a calibrated respiratory inductive plethysmograph before and during mechanical ventilation in 5 children and young adults with neuromuscular disease and paradoxic breathing at rest. Asynchrony of CWM was quantitated by measuring the phase shift, 0, between RC and AB motion (0° = synchronous motion, 180° = paradoxic motion). The volume contribution of the paradoxing compartment totidal volume (PC/VT,) was calculated. Before mechanical ventilation, mean±SEM VT was 122±17 mL, 0 was 131±15°C, and PC/VT was −27±6%. During mechanical ventilation, VT increased to 274±17 mL (P < 0.05), 0 decreased to 41±14° (P < 0.05), and PC/VT increased to +39±9% (P < 0.02). We conclude that mechanical ventilation improves RC/AB asynchrony and reverses the negative contribution to tidal volume of the paradoxing compartment in children and young adults with neuromuscular disease. This implies that mechanical ventilation assumes most or all the role of the respiratory pump in these patients, which provides a rationale for the use of chronic or nighttime ventilation in the treatment of respiratory muscle fatigue. Assessment of CWM may be useful in the determination of optimal ventilator settings in this population. Pediatr Pulmonol. 1993; 16:89–95. © 1993 Wiley‐Liss, Inc.
Meconium aspiration syndrome: Physiological and inflammatory changes in a newborn piglet model
Authors: Davey Andrew M. , Becker Jennifer D. , Davis Jonathan M.
Published: March 2007

In order to evaluate further the physiological and inflammatory changes of meconium aspiration syndrome (MAS), 25 newbom piglets (1‐2 days old, 1.5±0.4 kg) were studied. Piglets were briefly ventilated with 100 % oxygen and then received an intratracheal bolus of 3 mL/kg of a 20% suspension of human meconium. They were then further ventilated, keeping PaCO2, at approximately 40 torr and PaO2 at 70 torr during 4, 12,24, and 48 h studies. Pulmonary function studies and tracheal aspirates were obtained at time zero and serially throughout the study. Bronchoalveolar lavage was performed at the end of the study to examine endogenous surfactant function. Control piglets received 3 mL/kg of intratracheal saline and were then ventilated for 48 h at an inspired oxygen concentration and mean airway pressure matched to the meconium treated group (to control for the effects of hyperoxia and barotrauma on the lung). MAS caused acute decreases in gas exchange and dynamic lung compliance, which returned toward baseline by 48 h (P<0.001, ANOVA). Tracheal aspirate absolute neutrophil count, neutrophil chemotactic activity, albumin, and total protein concentrations also increased significantly over time (P<0.001). Endogenous surfactant function appeared to be significantly inhibited by the meconium. All variables of lung injury were significantly higher in the meconium group compared to the saline control group over the 48 h study. Newborn piglets provide a clinically relevant model of MAS, demonstrating physiological and inflammatory changes with apparent alterations in endogenous surfactant function. Effective therapies for MAS may require interventions directed at all of these components of lung injury. Pediatr Pulmonol. 1993; 16:101–108. © 1993 Wiley‐Liss, Inc.
Lung function and bronchial challenges in infants: Repeatability of histamine and comparison with methacholine challenges
Authors: Stick S. M. , Turner D. J. , Lesouéf Peter N.
Published: March 2007

Limited information exists regarding the repeatability of lung function and bronchial challenge tests using the rapid thoracic compression technique (RTC) in infants. Aims: To determine the repeatability of lung function and histamine challenge test results using the RTC technique and to compare the results obtained for bronchial challenges using histamine (H) and methacholine (M). Methods: Twelve infants 7 healthy, 5 with cystic fibrosis (CF) had pairs of H challenges 1 week apart. Eleven infants (7 healthy, 4 CF) had one H and one M challenge a week apart. The provocative concentration of H or M to cause a 40% fall in maximum flow at functional residual capacity (PC40) was determined using the RTC technique. Twenty‐three comparisons were possible between maximal expiratory flow at functional residual capacity (VmaxFRC) measurements made l week apart. Results: The mean difference between pairs of VmaxFRC measurements was 6.4% of baseline, and the coefficient of repeatability was 31.1% of baseline. The mean difference between PC40(H) measurements was 0.163 doubling concentrations, with a coefficient of repeatability of 1.66 doubling concentrations. The mean difference between PC40(H) and PC40(M) was 0.75 doubling concentrations, with 95% of PC40(H) between −0.18 to 1.69 doubling concentrations of the PC40(M). Conclusions: Although the repeatability of VmaxFRC using the RTC technique is less than for voluntary forced expiratory flow parameters in older children, similar results were obtained for infants as observed in older subjects for repeatability of H challenges and agreement between measures of bronchial responsiveness using H or M. Pediatr Pulmonol. 1993; 16:177–183. © 1993 Wiley‐Liss, Inc.
Referencing lung volume for measurements of respiratory system compliance in infants
Authors: Mortola J. P. , Hemmings G. , Matsuoka T. , Saiki C. , Fox G.
Published: March 2007

We propose a method for measurements of respiratory system compliance (Cm) in spontaneously breathing infants, which circumvents the potential problems introduced by the breathby‐breath oscillations in the end‐expiratory level, i.e., functional respiratory capacity (FRC). Changes in lung volume (V) and pressure at the airway opening (Pao) were measured in 10 infants breathing through a face mask. A first brief occlusion was to establish a reference V and the corresponding static Pao; a second occlusion was done at a different V. within the same expiration, or in the following breath. Both occlusions were sufficiently long for the establishment of a stable Pao value. From the V difference (Δ, where Δ was at least 20% tidal volume) and the corresponding difference in Pao (Δao) Crs was computed and averaged (Crs[REF.VOL.] = Δ/δao). Although, on average, the results were similar to those obtained by the traditional multiple occlusions technique with linear regression analysis of the Pao‐V data points (Cao[MOT]), in several infants Crs[REF.VOL] tended to be slightly higher than Crs[MOT]. Some possibilities for this discrepancy are discussed. It seems likely that breath‐tobreath oscillation in FRC may potentially lower Crs[MOT] by introducing a bias on the V measurement at low Pao. We conclude that referencing V for Crs measurements in spontaneously breathing infants is a simple approach, which does not require linear regression analysis and Circumvents the effects of oscillation in FRC. Pediatr Pulmonol. 1993; 16:248–253. © 1993 Wiley‐Liss, Inc.
Comparison of efficacy of salbutamol and sodium cromoglycate in the prevention of ticarcillin‐induced bronchoconstriction
Authors: Chua Hock Leng , Walker Sharyn L. , Lesouëf Peter N. , Sly Peter D.
Published: March 2007

Nebulized ticarcillin can cause bronchoconstriction in children with cystic fibrosis (CF). We assessed whether pretreatment with salbutamol or sodium cromoglycate (SCG) would prevent this side‐effect using a randomized, double‐blind, placebo‐controlled design. Fifteen children with CF received pretreatments of saline, SCG, or salbutamol, in random order, one on each day. Baseline lung function was measured before and after pretreatment, and after ticarcillin nebulization. On the control day (saline pretreatment), ticarcillin caused a reduction in forced expiratory volume in one second (FEV1), which was maximal 10 minutes after receiving the aerosol and persisted for 120 minutes. The mean maximal fall in FEV1, was 9%. Pretreatment with salbutamol abolished the fall in FEV, seen with ticarcillin at all time points. Pretreatment with SCG diminished the maximal fall in FEV1, at 10 minutes (mean, 4%) and resulted in the FEV, returning to baseline within 120 minutes. These data suggest that pretreatment with salbutamol is more effective in preventing ticarcillin‐induced bronchoconstriction in the doses used in routine clinical practice, than it is with SCG. Pediatr Pulmonol. 1993; 16:311–315. © 1993 Wiley‐Liss, Inc.
Cardiorespiratory effects of conventional and high frequency ventilation in rabbits with bilateral pneumothoraces and surfactant depleted lungs
Authors: Wang Chen , Nicol Margaret E. , Chakrabarti Mihir K. , Holdcroft Anita , Whitwam James G.
Published: March 2007

We compared high frequency ventilation (HFV) to conventional mechanical ventilation (CMV) under normoxic and normocapnic condition in surfactant depleted rabbits with bilateral pneumothoraces. We hypothesized that lower airway pressures would be required with HFV under these conditions. We applied CMV and HFV in 8 anaesthetized rabbits with a prototype ventilator at frequencies of 30, 100,200, and 300 cycles/min. A positive end‐expiratory pressure (PEEP) just below the pressure sufficient to open the air leak from the pneumothoraces was applied at all frequencies. Airway pressures, gas exchange, heart rate, and mean arterial pressure were recorded. Peak airway pressure decreased significantly from 2.50 to 2.10 kPa when the frequency of ventilation was increased from 30 to 300 cycleshnin. There were no significant changes in mean airway pressure, Pao2arterial pH, heart rate, and mean arterial pressure when HFV was compared to CMV. In conclusion, during HFV peak airway pressures measured at the mouth were decreased. Our ability to maintain adequate gas exchange in the face of ongoing pulmonary air leaks may reflect lower alveolar pressures. Pediatr Pulmonol. 1993; 16:354–357. © 1993 Wiley‐Liss, Inc.
Slow weight gain is associated with increased periodic breathing in healthy infants
Authors: Riordan Linda L. , Kelly Dorothy H. , Shannon Daniel C.
Published: March 2007

To investigate the hypothesis that weight gain can influence periodic breathing in healthy infants, we prospectively studied, by nocturnal pneumogram technique, respiration and heart rate in 99 full‐term infants during the first month of life. Eighty‐eight infants had a repeat study at about 2 months of age. Pneumograms were analyzed visually for percent periodic breathing (%PB), and by computer for mean respiratory rate and mean heart rate. We found a median %PB of 0.9 initially and of 0.3 at about 2 months of age. The 95th percentile was 13.5 at 2 weeks and 7.3 at 2 months, higher than previously reported. Between the two ages tested, %PB was inversely correlated with weight gain (P < 0.001, (0.03, respectively). Infants with greater weight gain had a greater fall in %PB (P < 0.03). We conclude that in the first 2 months of life, slow weight gain is associated with increased periodic breathing. Pediatr Pulmonol. 1994; 17:22–25. © 1994 Wiley‐Liss, Inc.
The effects of reversing distending pressure sequences in the neonatal piglet
Authors: Easa David , Mundie Thomas G. , Finn Kuuleialoha C. , Balaraman Venkataraman , Stevens Edward L. , Takenaka Wayne , Uyehara Catherine F. T.
Published: March 2007

We studied different sequences of lung inflation in ventilated newborn piglets with normal lungs in order to determine the effects of sequence, magnitude and duration of distending pressure on pulmonary function, and/or hemodynamics. End‐expiratory pressure was varied using a continuous negative extrathoracic pressure (CNEP) device. Three groups of ventilated piglets with normal lungs were exposed to 2 cmH2O increments of CNEP from −2 to −12 cmH2O and to decrements from −12 to −2 cmH2O or to only ‐6 cmH2O. Lung inflation sequence, magnitude of inflation pressure, and duration of inflation had significant effects on end‐expiratory lung volume and lung compliance at numerically equivalent pressure levels. End‐expiratory lung volume and lung compliance varied (at four and five of six inflation pressures studied) by as much as 68% and 104%, respectively. Hemodynamic effects of the lung inflation sequence were more variable; those found to be different at numerically equivalent pressure levels were associated with changes in lung compliance and ventilation. Differences in pulmonary mechanics can best be explained by the effects of lung inflation on alveolar recruitment versus overinflation. Pediatr Pulmonol. 1994; 17:97–105. © 1994 Wiley‐Liss, Inc.
Radiographic lung disease and response of persistent pulmonary hypertension to mean airway pressure and alkalosis
Authors: Deluga Karl S. , Schlesinger Alan E.
Published: March 2007

Persistent pulmonary hypertension of the newborn (PPHN) is associated with multiple cardiopulmonary diseases. Therapy often includes hyperventilation/alkalosis despite little evidence as to its efficacy in diverse conditions. To determine (1) if part of the improvement of arterial oxygen tension (P) attributed to alkalosis is actually related to increased mean airway pressure (Paw) and (2) if the presence of radiographic pulmonary disease predicts the response to alkalosis or mean airway pressure, we reviewed records of 19 newborns with well‐documented PPHN. Arterial blood gases and corresponding ventilator settings were recorded during the first day of life. To adjust for lower F corrected P(cP) was calculated when the F < 1.0, such that cP = calculated arterial/alveolar oxygen ratio x (71 3 ‐ P/0.8). Regression equations were obtained and mean slopes of these were compared for Paw vs. cP, and pH vs. cP by one group t‐tests (with assumed population slope of zero). There was no correlation between Paw and cP (mean slope ± SD = −8.4 ± 30.8, P = 0.25), but there was a moderate correlation between p d and cP (mean slope = 333.1 ± 480.5, P = 0.007). Patients were then classified by chest radiographs as having severe or minima/no lung disease. Relationships of Paw and pH to cP were then re‐examined. No correlation was present between Paw and cP, in 11 patients with PPHN and severe radiographic disease (mean slope = −7.4 ± 26.97 P = 0.38) or in eight patients with PPHN and minima/no lung disease (mean slope = −9.8 2 37.5, P = 0.48). There was no correlation between pH and CP in patients with severe radiographic lung disease and PPHN (mean slope = 92.1 t 399.5, P 7 0.46), but patients with PPHN and minimal/no lung disease showed a strong correlation (mean slope = 664.5 ± 385.8, P = 0.002). We conclude that Paw (≤18 cm H2,O) with conventional mechanical ventilation has no apparent effect on oxygenation in patients with PPHN regardless of lung disease; however, severe radiographic lung disease may be a predominant variable predicting a poor response to alkalosis. We speculate that different diseases cause pulmonary hypertension by different mechanisms. Pediatr Pulmonol. 1994; 17:239–245. © 1994 Wiley‐Liss, Inc.
Pneumotachographic nitrogen washout method for measurement of the volume of trapped gas in the lungs
Authors: Gustafsson Per M. , Johansson Helmer J. , Dahlbäck Gunnar O.
Published: March 2007

A computerized pneumotachometric multiple breath N,‐washout method for assessment of the volume of trapped gas in the lungs (V ) is presented. The V is measured as the volume of air mobilized from nonventilated lung spaces by five maximal breaths after a washout performed until the end‐tidal nitrogen fraction is 0.02.

The method demonstrated a good instrumental precision and the reproducibility of V recordings in normal subjects was equal to that achieved with a previous V method based on gas collection in bags.

It was confirmed that gas trapping occurs in normal children during tidal breathing at functional residual capacity. In normal subjects V was directly related to lung size. In 69 healthy children and adolescents V showed a good correlation with vital capacity (r = 0.85; P < 0.001), of which it comprised 1.7 ± 0.4% (mean 5 SD). Patients with bronchial asthma or cystic fibrosis investigated had pathological gas trapping with only a few exceptions; in several cases despite normal results at forced expiratory spirometry. The relative response of V (reflecting peripheral airway obstruction) and forced expiratory volume in one second (FEV1) (reflecting conditions in central airways) to beta,‐agonist inhalation among the patients with asthma was variable, indicating that bronchial obstruction is not uniformly distributed along the bronchial tree.

Measurements of V can be easily performed in children from 7 years of age with the method presented. The computerized V method facilitates work and saves time for the operator and provides instant test results. V appears to be a sensitive indicator of peripheral bronchial obstruction, giving supplemental information to standard spirometry. Pediatr Pulmonol. 1994; 17:258–268. © 1994 Wiley‐Liss, Inc.
Protective effect of albuterol delivered via a spacer device (Babyhaler®) against methacholine induced bronchoconstriction in young wheezy children
Authors: Avital Avraham , Godfrey Simon , Schachter Jacob , Springer Chaim
Published: March 2007

Nine young asthmatic children aged 2–5 years underwent methacholine challenge after placebo or albuterol administered by metered dose inhaler through a spacer device (Babyhalere®)* with a face mask in a double‐blind, cross‐over, randomized study. The methacholine challenge was performed using chest auscultation to define the provocative concentration of methacholine that causes wheezing (PCW). The PCW increased from a geometric mean of 0.28 mg/mL after placebo to 3.59 mg/mL after albuterol (P < 0.0001). The protective effect of albuterol against methacholine‐induced bronchospasm was 3.7 ± 1.2 doubling doses. We conclude that administration of drugs from a metered dose inhaler through the Babyhaler® with a face mask is effective. Albuterol causes a major reduction in the bronchial hyperreactivity in young wheezy children shortly after administration. Pediatr Pulmonol. 1994; 17:281–284. © 1994 Wiley‐Liss, Inc.
Nasal response to inhaled histamine measured by acoustic rhinometry in infants
Authors: Kano Sohei , Pedersen Ole F. , Sly Peter D.
Published: March 2007

Aerosolized histamine, delivered via a face mask, is commonly used to evaluate bronchial reponsiveness in infants. To investigate nasal response to inhaled histamine we have measured nasal passage geometry in 32 infants by the use of acoustic reflections. Satisfactory data were obtained from only 17 infants (12 males, 5 females, 6.6 ± 4.4 months), because of awakening prior to completing the study in the remaining 15 infants. Acoustic rhinometry provided nasal cavity volume at 4 cm from the entrance of the nostril (VO4), the minimum cross‐sectional area (Amin), and the distance from the nostril to Amin (Dmin). Nasal geometry and lung function (maximum expiratory functional residual capacity [VmaxFRC] were measured before and immediately after a histamine challenge test using rapid thoratic compression. The histamine aerosols decreased both VO4 and Amin significantly by a mean of 17% and 13%, respectively (P < 0.001). There was a small, but significant increase (mean = 0.19 cm) of Dmin in the right side only, indicating a posterior dislocation of the narrowest site with swelling of the mucous membrane. In general, we found a dose‐response relationship in grouped data, with a greater fall in VO4 with increasing dose of histamine, but there was no correlation between percent fall in VO4 and VmaxFRC. This pilot study suggests that histamine aerosol affects nasal cavity geometry and that of acoustic rhinometry in infants and children warrants further investigation. Pediatr Pulmonol. 1994; 17:312–319. © 1994 Wiley‐Liss, Inc.
Relationship between atopy and frequent bronchial response to exercise in school children
Authors: Frischer T. , Meinert R. , Karmaus W. , Urbanek R. , Kuehr J.
Published: March 2007

The natural history of a bronchial response to exercise (BRE) was studied in a cohort of primary‐school children, who were followed over a 2‐year period. In 1,094 children, three free‐running tests were performed in 1 ‐year intervals. Children who responded in one of the tests were designated as “infrequent” responders (20.5%), whereas those responding at two or all three occasions were designated as “frequent” responders (7.4%). A frequent positive BRE was closely associated with atopy (defined as skin test positivity to 1 of 7 common aeroallergens) and respiratory symptom status. Compared to atopics without respiratory symptoms, an increased risk for a frequent positive BRE was seen for atopic children who were symptomatic during the whole study period [odds ratio (OR) 25.4; confidence interval (CI) 6.9–94.01, who had gained symptoms (OR, 11.0; CI, 2.8–43.2) or who had symptoms at the beginning of the study but had lost them during follow‐up (OR, 4.6; CI, 1.0–20.6). A sensitization to dust mites (OR, 8.0; CI, 4.3–15.0) but not to animal dander (OR, 2.3; CI, 1.0–5.2) or pollen (OR, 0.7; CI, 0.3–1.6) was significantly related to a frequent positive BRE. Our findings support the notion that while “children grow out of asthma,” they might maintain their bronchial hyperresponsiveness. Regarding specific sensitization, mite allergy seems to play the predominant role. Pediatr Pulmonol. 1994; 17:320–325. © 1994 Wiley‐Liss, Inc.
Measurement of chloride concentration in microvolume samples of sweat
Authors: Nathanson Ian , Tucker Marie , Jones Linda
Published: March 2007

Measuring sweat CI concentration requires multiple steps. Following pilocarpine iontophoresis we compared CI concentrations of sweat obtained on gauze pads to microvolumes (5 μL) collected into capillary tubes (N = 111). Chloride concentrations obtained by these two methods correlated significantly (r = 0.95; P < 0.001), indicating that CI concentration can be measured accurately and easily on small volumes. Pediatr Pulmonol. 1994; 17:340–342. © 1994 Wiley‐Liss, Inc.
Functional residual capacity and total respiratory system impedance in wheezing infants
Authors: Desager K. N. , van Bever H. P. , Willemen M. , De Backer W. , Vermeire P. A.
Published: March 2007

Airways obstruction has been demonstrated in acutely wheezing infants. The aim of the present study was to assess functional abnormalities as detected by measurement of total respiratory system resistance (Rrs) and functional residual capacity (FRC) in infants with a history of recurrent episodes of wheezing, while not acutely ill. In 30 such infants (mean age, 10 months; range, 4–17) and in 10 healthy infants (mean age, 6 months; range, 0–14) four Rrs measurements, performed with the forced pseudo‐random noise (PRN) oscillation technique, and three FRC determinations, using the closed‐circuit helium dilution technique, were averaged. A lower than predicted FRC was demonstrated in 20/30 (66%) patients. At 16 Hz, Rrs was significantly above predicted in 3/30 (10%) patients. Specific Rrs (Rrs × FRC) at 16 Hz was increased in 5/30 (17%) patients. In conclusion, the PRN oscillation technique combined with FRC measurement by helium dilution detects lung function abnormalities in a minority of wheezing infants during symptom‐free intervals. Pediatr Pulmonol. 1994; 17:354–358. © 1994 Wiley‐Liss, Inc.
In vitro suppression of Pseudomonas cepacia after limited exposure to subinhibitory concentrations of amiloride and 5‐(N,N‐hexamethylene) amiloride
Authors: Cohn Robert C. , Rudzienski Lois
Published: March 2007

Amiloride (A) for aerosolized therapy in cystic fibrosis (CF) is under investigation. Antipseudomonal properties of A and A analogs in vitro have recently been described. This study was performed to determine if there was suppression of P. cepacia growth after a limited 2‐hour exposure to (subinhibitory) concentrations of A ± tobramycin (T) or to the analog 5‐(N,N‐hexamethylene) amiloride (HMA) in vitro. The MIC of each drug against five different P. cepacia strains was determined. Cells were prepared in Mueller Hinton broth to [106] colony forming units (CFU)/mL and incubated at 35°C for 2 hours in the presence and absence of subinhibitory A, HMA, T, or A + T. The CFU were measured before and at 1 ‐hour intervals after dilutional removal of drug. The post‐antibiotic effect (PAE) was defined as the time (in minutes) required for the test culture counts to increase 10‐fold minus the time required for control counts to increase 10‐fold. At 400 μ/mL or 200 μ/mL, the PAE for A against five different strains was 139 ± 23 and 83 f 24 (mean 5 SD) minutes, respectively. For 100 μ/mL and 50 μ/mL HMA, the PAE was 122 ± 38 and 65 f 25 minutes. For T and A + T (200 μ/mL + 32 μ/mL) the PAE was 168 ± 30 and 258 ± 30 minutes. We conclude that A and the analog HMA in (subinhibitory) concentrations have a suppressive effect on P. cepacia after drug removal and potentiate the effect of T in vitro. Pediatr Pulmonol. 1994; 17:149–154. © 1994 Wiley‐Liss, Inc.
Management of severe congenital tracheobronchomalacia by continuous positive airway pressure and tidal breathing flow‐volume loop analysis
Authors: Reiterer Fritz , Eber Ernst , Zach Maximilian S. , Müller Wilhelm
Published: March 2007

We report on a now 9‐month‐old infant with severe tracheobronchomalacia associated with campomelic dysplasia. The diagnosis of tracheobronchomalacia was suggested in the neonatal period by typical changes of the tidal breathing flow‐volume loop and was confirmed by tracheobronchoscopy. Tidal breathing flow‐volume loop analysis also allowed to titrate the optimal, continuous positive airway pressure for the respiratory management of the patient. Since bedside pulmonary function testing is noninvasive and rapid, it may reduce the need for frequent bronchoscopic evaluations in the management of patients with tracheobronchomalacia. Pediatr Pulmonol. 1994; 17:401–403. © 1994 Wiley‐Liss, Inc.
Inadvertent removal of foreign body via a flexible fiberoptic bronchoscope in a 4‐year‐old boy
Authors: Akhter Javeed , Gaspar Michele , Bassuk Angel , Roberts Jack
Published: March 2007

We report the case of a 4‐year‐old child with an atypical presentation of an aspirated unwitnessed foreign body in the airway. During an attempt to obtain a biopsy of what appeared to be a mucosal growth, the foreign body was removed. This may be the first report of foreign body removal in a child this young, using a flexible fiberoptic bronchoscope. Pediatr Pulmonol. 1994; 18:51–52. © 1994 Wiley‐Liss. Inc.
Unilateral cervical spinal cord lesion in a term newborn, associated with ipsilateral diaphragmatic atrophy and pulmonary hypoplasia
Authors: Rotschild Avi , Ling Emily W. Y. , Wensley David F. , Norman Margaret G. , Thurlbeck William M.
Published: March 2007

Two major factors can interfere with normal development of the fetal lungs: mechanical constriction resulting in decreased intrathoracic space and reduced or absent fetal breathing movements. We report a unique case in which both factors contribute to the development of lethal pulmonary hypoplasia. This full‐term neonate had an isolated unilateral lesion in the cervical spinal cord resulting in ipsilateral neurogenic atrophy of the diaphragm, bilateral pulmonary hypoplasia, and lung immaturity. Evenetration of the atrophied diaphragm decreased intrathoracic space, compromising fetal lung growth. This was compounded by impaired fetal respiration due to the diaphragmatic atrophy, further aggravating pulmonary hypoplasia on the affected side. The other lung was also hypoplastic, although to a lesser degree, suggesting that its growth was also affected by either or both of these factors. Pediatr Pulmonol. 1994; 18:53–57. © 1994 Wiley‐Liss. Inc.
Brain cell membrane modification following hypercapnia and recovery in newborn piglets
Authors: Schneiderman Roy , Kubin Joanna , Mishra Om Prakash , Delivoria‐Papadopoulos Maria
Published: March 2007

The effect of hypercapnia on brain cell membrane structure and function was studied in anesthetized newborn piglets. Lipid peroxidation products (conjugated dienes and fluorescent compounds), Na+,K+‐ATPase activity and enzyme affinity to ATP (substrate), K+ and Na+ ions (activators), and strophanthidin (inhibitor) were measured in three groups of animals: controls, those exposed to 90 minutes of Paco2 > 80 mmHg (hypercapnia) and those exposed the same way, following restoration of normal Paco2, (recovery). Enzyme activity was unchanged by hypercapnia, but enzyme affinity was altered as indicated by an increase in ATP affinity. Affinities to Na+, K+, and strophanthidin were unchanged. Restoration of normal Paco2 resulted in an increase in conjugated dienes. The data demonstrate that hypercapnia followed by restoration of normal Paco2 in healthy term newborn piglets is associated with mild modification of brain cell membrane Na+, K+‐ATPase, possibly due to lipid peroxidation.Pediatr Pulmonal. 1994;18:81–88. © 1994 Wiley‐Liss, Inc.
Role of positive end‐expiratory pressure changes on functional residual capacity in surfactant treated preterm infants
Authors: da Silva Wanderlan José , Abbasi Soraya , Pereira Gilberto , Bhutani Vinod K.
Published: March 2007

Both surfactant replacement and positive end‐expiratory pressure (PEEP) increase lung volume in infants with respiratory distress syndrome (RDS). We measured pulmonary mechanics and functional residual capacity (FRC) in 21 preterm infants with RDS, > 48 hr post‐surfactant therapy (BW, 1,168 ± 441 g; GA, 28.3 ± 2.8 weeks; postnatal age, 3–7 days). A non‐linear but significant increase in mean FRC was noted as PEEP increased from 2 to 5 cmH2O: 18.4 ± 4.7mL/kg at 2 cmH2O; 19.7 ± 4.3 mL at 3 cm H2O; 22.6 ± 5.5ml/kg at 4 cmH2O; and 26.2 ± 6.2 mL/kg at 5 cmH2O (P < 0.01). Because of the synergistic combined effect on lung volume, surfactant treated neonates should be weaned cautiously from PEEP during ventilatory management. Our study also suggests that the occurrence of inadvertent end‐distending pressure during FRC measurement in the ventilated neonate lead to erroneous results.Pediatr Pulmonal. 1994;18:89–92. © 1994 Wiley‐Liss, Inc.
An expanded scoring system including an index of nutritional status for patients with cystic fibrosis
Authors: Cabrera Marco E. , Lough Marvin D. , Doershuk Carl F. , Salvator Ann E.
Published: March 2007

Evaluation of success or failure of therapy for patients with cystic fibrosis (CF) commonly relies on the results of a single pulmonary function test (PFT). Most PFT measurements reflect different functional aspects of the lung. Although no single parameter can summarize all aspects of lung function, a combination of several may provide an advantage by reflecting the overall abnormality of lung function in one number. Cropp et al. (1982, Am Rev Respir Dis 126:211–216) developed a multiparameter pulmonary function score (PFS) using the results of six separate parameters obtained from a PFT. In CF, there is also the potential for declining nutritional status (NS), leading to malnutrition and skeletal muscle wasting. Our aim was to expand the PFS by including weighted information on NS, and to determine whether the expanded score (nutritional‐pulmonary function score, NPFS) was more sensitive in detecting change in outcome variables than the PFS. Individual PFT parameters, percent ideal body weight (%IBW), and an index of anaerobic performance (AP) were measured in 21 patients on admission to the hospital and again at discharge. In the group as a whole, in‐hospital therapy resulted in improvement (P < 0.01) in individual PFT parameters, YJBW, PFS, and NPFS, and no change in AP. While the PFS more effectively reflected improvement in lung function than did any single PFT parameter, the NPFS resulted in an even more sensitive index of change. Based on these results, we believe that the NPFS, which includes both lung and nutritional status, provides an effective and sensitive index of disease severity that can be used as a unifying measure to: (1) detect disease progression; (2) guide rehabilitation and training; (3) stratify patients for clinical trials; or (4) evaluate the effects of a therapeutic intervention.Pediatr Pulmonol. 1994;18:199–205. ©1994 Wiley‐Liss, Inc.
Effects of breathing a normoxic helium mixture on exercise tolerance‐of patients with cystic fibrosis
Authors: Martin Daniel , Day Jane , Ward Glenn , Carter Edward , Chesrown Sarah
Published: March 2007

Breathing helium‐oxygen (HeO2,) mixtures of 20.9% O2/79.1% He has been shown to increase exercise ventilation and peak oxygen uptake in healthy subjects. The improved exercise performance is thought to be due to the reduced density of HeO2 compared to air and the resulting increases in ventilation. Patients with cystic fibrosis (CF) frequently have abnormal pulmonary function test results, low exercise ventilations and diminished exercise tolerance. This led to the hypothesis that in CF the exercise tolerance of patients might improve when breathing HeO2. To test this hypothesis, 11 patients with CF or mild to severe airway obstruction performed spirometry and progressive maximal exercise tests while breathing air or HeO22. The HeO2 mixture significantly increased (P <0.05) forced expiratory volume in 1 sec (FEV1) by 8.2%, peak expired flow by 39%, and maximal voluntary ventilation (MVV) by 17.9% compared to air, while forced vital capacity (FVC) and forced mid‐expiratory flow rate (FEF25–75%,) were unchanged by breathing HeO2. Ventilation and oxygen uptake at matched submaximal power outputs were not increased while breathing HeO2. nor were peak exercise ventilation (V̇Epeak) or peak exercise oxygen uptake (V̇O2peak). Estimated hemoglobin saturation and total exercise time were also unchanged during HeO2, breathing. However, there was a trend for the subjects with the better FEV1, to increase V̇O2peak. Increases in V̇O2peak when breathing HeO2, and air were correlated (r = 0.67, P<0.05) with the percent of predicted FEV, values. Still, in the 11 patients as a group, breathing HeO2, did not significantly improve V̇O2peak V̇Epeak or exercise tolerance. Therefore HeO2, is unlikely to have additional benefits to patients with CF who use an exercise program to help optimize their health status.Pediatr Pulmonol. 1994;18:206–210. ©1994 Wiley‐Liss, Inc.