bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of sidestream smoke exposure and age on pulmonary function and airway reactivity in developing rats
Authors: Joad Jesse P. , Pinkerton Kent E. , Bric John M.
Published: March 2007

Children exposed to environmental tobacco smoke (ETS) in their homes have in‐ creased cough, respiratory illness, airway obstruction, and hyperreactivity. Since an animal model is needed to understand the mechanism by which this occurs, our study was designed to determine if immature rats develop airway obstruction and increased airway reactivity when exposed to sidestream smoke (SSS, respirable suspended particulate concentration 1.00±0.03 mg/m3, CO concentration 6.48±0.29 ppm). In the first of 3 studies, rats were exposed to filtered air (FA) or SSS for 6 hr/day, 5 days/week from day 2 to week 8 or week 15 of life (n = 6‐8 in each group). SSS exposure did not change lung resistance (RJ, dynamic lung compliance (Cldyn), lung weighthody weight ratio (LW/BW), pulmonary artery pressure (PPA), body weight, or airway reactivity to methacholine (all P > 0.2, 2‐way ANOVA). Regardless of exposure, lungs from younger rats were relatively heavier and more reactive to methacholine than lungs from older rats (P < 0.05, 2‐way ANOVA). In the second study, 15‐week‐old rats were exposed to FA or SSS for 3 hr or for 4 days (6 hr/day, n = 6 in each group). SSS exposure again had no effect on Cldym RL, LW/BW, Ppa, or airway reactivity to methacholine (all P > 0.2, ANOVA). In the third study, rats were exposed to FA or SSS from day 2 to week 11 of life (n = 7 in each group). SSS exposure reduced airway (P = 0.004) but not pulmonary artery (P = 0.63) reactivity to serotonin. We conclude that (1) SSS exposure to the immature rats did not mimic the effects of ETS seen in children, (2) younger rats had greater muscarinic airway reactivity than older rats, and (3) serotonin may play a role in ETS‐induced lung problems.Pediatr Pulmonol. 1993; 16:281–288. © 1993 Wiley‐Liss, Inc.
Effect of amrinone during group B Strepfococcus‐induced pulmonary hypertension in piglets
Authors: Berger James I. , Gibson Ronald L. , Clarke William R. , Standaert Thomas A. , Redding Gregory J. , Henderson William R. , Truog William E.
Published: March 2007

Intravenous infusion of group B Streptococcus (GBS) into neonatal animals pro‐ duces pulmonary hypertension, ventilation/perfusion (V̇A/Q̇) mismatch, and an increase in serum levels of thromboxane B2, (TxB2) and tumor necrosis factor (TNF)α. The vasodilator amrinone (amr) is a cGMP‐inhibited phosphodiesterase inhibitor and is reported to inhibit thromboxane A2 and TNF production. We hypothesized that infusion of amr would cause pulmonary vasodilation and reduce serum TxB2, and TNF levels in piglets with late phase GBS‐induced pulmonary hypertension. The effect of amr on gas exchange was also determined. A continuous infusion of GBS was administered for 5 hr to 4 groups of anesthetized, mechanically ventilated neonatal piglets. An amr bolus of 8 mg/kg was given at 4 hr followed by a 1 hr continuous infusion of either 10 or 20μg/kg/min of amr (amr 10 and amr 20, respectively). Control piglets received a bolus and 1 hr infusion of amr carrier. The infusion of amr, but not of carrier reversed late phase GBS‐ induced pulmonary hypertension. Piglets infused with amr 20 showed transient selective pulmo‐ nary vasodilation, based on a reduced ratio of pulmonary to systemic vascular resistance (PVW SVR ratio) value at 30min but not at 1 hr. compared to pre‐amr treatment values. The PVR/SVR ratio values for amr 10 and control group did not change after treatment with either amr or carrier. Treatment with amr 10 or 20 did not decrease serum TxB2, or TNF levels or increase VA/Q mismatch. A subsequent group of piglets received an 8 mg/kg bolus and 40 μg/kg/min infusion of amr (amr 40) to determine if the increased infusion rate would sustain a selective pulmonary vasodilatory effect beyond 30 min. The PVR/SVR ratio values for amr 40 did not change after treatment for 30 min or 1 hr, compared to pretreatment values. We conclude that amr is effective in reversing GBS‐induced pulmonary hypertension. However, the reduction in SVR caused by amr may preclude its use in septic newborns. Pediatr Pulmonol. 1993; 16:303–310. © 1993 Wiley‐Liss, Inc.
Contrasting clinical and statistical significance within the research setting
Authors: Lindgren Bruce R. , Wielinski Catherine L. , Finkelstein Stanley M. , Warwick Warren J.
Published: March 2007

When designing a clinical trial or study, the value of the following interrelated parameters should be determined prior to collecting data: clinical significance, statistical significance, power, and sample size. Too often, clinical importance and the other design issues are ignored and only statistical significance dictates the conclusions of the study. In order to evaluate the frequency that each of these design parameters is addressed in the published literature, the topic of pulmonary function tests (specifically forced vital capacity) was chosen, and all relevant articles for one year (1990) were identified using Minnesota MEDLINE. A total of 121 articles met the selection criteria and were reviewed. Of all the articles, 13.2% discussed clinical significance, 21.5% discussed sample size, and only 5.0% addressed statistical power. As expected, the majority of the articles (92.6%) discussed statistical significance (P values). None of the articles mentioned all four factors. When choosing the level of clinical significance several methods may be used. Such might be well established in certain clinical areas or available from previous publications and references or they may be attainable from pilot study data and, in the absence of any prior information, a clinician may use personal experience. To minimize subjectivity, the clinical effect‐size can be based on the population distribution of the measurement of interest. Pediatr Pulmonol. 1993; 16:336–340. © 1993 Wiley‐Liss, Inc.
Neonatal meconium aspiration syndrome and respiratory morbidity during infancy
Authors: Yuksel B. , Greenough A. , Gamsu H. R.
Published: March 2007

Respiratory morbidity in the first 6 months of life of 35 infants who had had neonatal meconium aspiration syndrome (MAS) was compared to that of 70 controls, also born at term, matched for gender and ethnic origin. The number of infants in the two groups who were symptomatic was compared. Infants were described as symptomatic if, following discharge from hospital, they had at least one episode of wheezing and/or coughing which lasted for 3 days or more. There was no significant difference between the two groups regarding parental smoking or the proportion of infants who had a family history of atopy. A significantly greater proportion of the MAS group (49%) than of the control group (20%) was symptomatic at follow‐up. Eight (23%) infants with MAS and 2 (3%) controls had symptoms which necessitated regular bronchodilator therapy. The 8 infants with MAS who were on maintenance bronchodilator therapy had required significantly longer neonatal respiratory support and had larger lung volumes at follow‐up than the other 27 infants. We conclude that neonatal meconium aspiration syndrome is associated with increased respiratory morbidity in the first 6 months of life. Pediatr Pulmonol. 1993; 16:358–361. © 1993 Wiley‐Liss, Inc.
Effect of endotracheal tube leakage on functional residual capacity determination by nitrogen washout method in a small‐sized lung model
Authors: Seidenberg Jürgen , Homberger Jürgen , von der Hardt Horst
Published: March 2007

The determination of functional residual capacity (FRC) would be extremely helpful for the controlled adjustment of mechanical ventilation in sick neonates and infants. However, these patients have small lung volumes and usually have been intubated by uncuffed endotracheal tubes (ETT). Therefore, the open‐circuit nitrogen washout technique (N2wo) may give false FRC values if the inspired oxygen concentration (F) is high and leakage around the ETT is present. We evaluated the N2wo as supplied by the Pediatric Pulmonary System 2600 (Sensor‐Medics) in a small‐sized lung model by 570 measurements using five different ventilator settings, an F increasing up to 0.9, different bypass flows between 0 and 12 L/min, and various patterns of leakage, either during inspiration or exhalation, or both. We found the most reliable results (error, 0.6%; CV, 0.7%) with a bypass flow of 6 L/min. Absolute N, volumes as small as 14 mL could be measured using an F as high as 0.9 with only slight loss of accuracy (error, 4%; CV, 2,8%). During leakage, FRC had been underestimated with a very strong correlation to the total amount of leakage over the measurement period, which was irrespective of the ventilatory parameters (r = 0.9, P < 0.001). The regression equation could, therefore, be used for FRC correction in the lung model. However, most of the miscalculation was due to N, loss during expiratory leakage, which quite simply and reliably can be excluded by an end‐inspiratory occlusion test. In conclusion, we evaluated an N2wo system with a lung model and found it suitable to measure small lung volumes as found in preterm babies, even if they were ventilated with high F. In the presence of leakage, exclusion of leakage by an end‐inspiratory occlusion was found t i be the most practical way of obtaining reliable FRC‐values. Pediatr Pulmonol. 1994; 17:106–112. © 1994 Wiley‐Liss, Inc.
Mucus transport mechanisms in relation to the effect of high frequency chest compression (HFCC) on mucus clearance
Authors: Hansen Leland G. , Warwick Warren J. , Hansen Kathleen L.
Published: March 2007

High frequency chest compression (HFCC) appears promising as a form of chest physiotherapy. Studies published by several clinical centers support its efficacy, and further clinical data are expected to become available. Pediatr Pulmonol. 1994; 17:113–118. © 1994 Wiley‐Liss, Inc.
Continuous negative extrathoracic pressure versus positive end‐expiratory pressure in piglets after saline lung lavage
Authors: Easa David , Mundie Thomas G. , Finn Kuuleialoha C. , Hashiro Glenn , Balaraman Venkataraman
Published: March 2007

Recent reports have suggested that substituting continuous negative extrathoracic pressure (CNEP) for positive end‐expiratory pressure (PEEP) may result in clinical benefits to infants with pulmonary disease. Other studies have suggested potential hemodynamic advantages. We compared the effects of CNEP and PEEP in 13 mechanically ventilated newborn piglets after acute lung injury induced by saline lavage. The piglets were instrumented, salinelavaged, and exposed to 15 minute periods of incremental CNEP (–3, –6, –9, –12 cmH2O) (n = 7) or PEEP (3, 6, 9, 12 cmH2O) (n = 6). We measured and/or calculated dynamic lung compliance (CLdyn), lung resistance (RL), end‐expiratory lung volume (EELV), blood gases, cardiac output (CO), heart rate (HR), transmural vascular pressures, and pulmonary and systemic vascular resistance. Pulmonary function abnormalities after saline lavage included decreased Pao2, CLdyn, EELV, and increased Paco2 and RL (P < 0.05). Except for decreased CO, lung inflation with both CNEP and PEEP resulted in large increases in PaO2 without major pulmonary or hemodynamic effects. Other than differences in EELV at 3, 6, and 9 cmH2O distending pressure, there were no differences in pulmonary function or hemodynamics between sequences of incremental CNEP and PEEP. We conclude that CNEP and PEEP are physiologically equivalent in this model of acute lung injury. Pediatr Pulmonol. 1994; 17:161–168. © 1994 Wiley‐Liss, Inc.
Infrared end‐tidal CO2 measurement does not accurately predict arterial CO2 values or end‐tidal to arterial P, gradients in rabbits with lung injury
Authors: Hopper Andrew O. , Nystrom Gerald A. , Deming Douglas D. , Brown Wesley R. , Peabody Joyce L.
Published: March 2007

End‐tidal Pco2 (P) measurements from two commercially available neonatal infrared capnometers with different sampling systems and a mass spectrometer were compared with arterial P (P) to determine whether the former could predict the latter in mechanically ventilated rabbits with b d without lung injury. The effects of tidal volume, ventilator frequency and type of lung injury on the gradient between P and P (ΔP) were evaluated. Twenty rabbits were studied: 10 without lung injury, 5 with saline lavage and 5 with lung injury by meconium instillation. Paired measurements of P by two infrared capnometers and a mass spectrometer were compared to P.

In the rabbits without lung injury, the values from the infrared capnometers and mass spectrometer correlated strongly with P (r ± 0.91) despite differences in the slopes of the linear regression between P and ±P and in ΔP. (P < 0.05). Values from the mainstream IR‐capnometer more closely approdmated the line of identity than the regression between the sidestream IR‐capnometer values or the mass spectrometer and P but tended to overestimate P. The ΔP was similar at all tidal volumes and ventilator frequencies, regardless of capnometer type. In the rabbits with induced lung injury, while there was a positive correlation between the slopes of the regression between P and P for both capnometers (r ≥ 0.70), none of the regression slopes approximated the line of identify. The ΔP was greater in rabbits with injured than noninjured lungs (P < 0.05). The ΔP was similar among capnometers regardless of tidal volume, ventilator frequency, or type of lung injury. The 95% confidence interval of plots P against P was large for rabbits with injured and noninjured lungs. The ΔP changed in an erratic manner with changing P.

We conclude that Pmeasurements by infrared capnometer or mass spectrometer does not accurately predict P or ΔP in the presence of lung injury, and should be used with caution in the management of critically ill infants. Pediatr Pulmonol. 1994; 17:189–196. © 1994 Wiley‐Liss, Inc.
Evaluation of the interrupter technique for the use of assessing airway obstruction in children
Authors: Carter Edward R. , Stecenko Arlene A. , Pollock Brad H. , Jaeger Marc J.
Published: March 2007

The purpose of this study was to determine if the interrupter technique, a noninvasive method for measuring airflow resistance, could be used to assess airway obstruction in children. In 107 children (74 with asthma, 12 with cystic fibrosis, and 21 without lung disease) conductance (mostly of airways) measured with the interrupter technique (Gint) was correlated with both forced expiratory volume in 1 second (FEV1) and the forced expired flow rate between 25% and 75% of vital capacity (FEF25–75. In addition, 17 children with significant airway obstruction due to asthma also had airway resistance measured by body plethysmography (Raw) before and after treatment. Resistance and conductance measurements made with the interrupter technique were subdivided into inspiratory (Rint‐insp, Gint‐insp) and expiratory (Rint‐exp Gint‐exp) values. In the 107 children, a high degree of linear correlation was found between Gint‐exsp and FEV1 for Gint‐insp, r = 0.77 (P < 0.001), and for r = 0.76 (P < 0.001). There was also good linear correlation between Gin, and FEF25–75 for r = 0.70 (P < 0.001), and for Gint‐insp, r = 0.67 (P < 0.001). In the 17 asthmatic children who were tested before and after treatment of their airway obstruction, Rint correlated highly with Raw; for Rint‐exp, r = 0.91 (P < 0.001), and for Rint‐insp, r = 0.83 (P < 0.001). The pre‐ to posttreatment changes in R, and Raw were similar. We conclude that the interrupter technique can be used to assess changes in airway obstruction, but normal values must be established and further investigation is required before the complete extent of its clinical utility will be known. Pediatr Pulmonol. 1994; 17:211–217. © 1994 Wiley‐Liss, Inc.
Ventilatory pump failure in premature newborns
Authors: Watchko Jon F. , Balsan Jon Michael J.
Published: March 2007

Objective: To determine the prevalence of ventilatory pump failure in premature (<34 weeks gestation) infants. Design: Prospective clinical evaluation of all neonatal intensive care unit (NICU) admissions over a 12 month period in a large, university affiliated hospital. Subjects: A series of 421 consecutive inborn premature infant admissions to the NICU. Methods: Infants were followed for signs and symptoms of respiratory distress and monitored closely for evidence of respiratory failure requiring in tubation and assisted ventilation. The indications for in tubation and assisted ventilation were reviewed, and three such indications were considered clear manifestations of ventilatory pump failure, that is, delivery room resuscitation with CXR negative for evidence of parenchymal lung disease [DR/CXR‐1, hypercapnia (P> 55 torr) [ ↑ CO2], and apnea.Results: A total of 192 premature infants (47% of study sample? required intubations and assisted ventilation. Failure of the ventilatory pump to sustain ventilation (DR/CXR‐, ↑ CO2apnea) accounted for 70 of these 192 (36%) premature infants. Conclusions: Ventilatory pump failure is a common clinical phenomenon in premature infants. Intensified research on the mechanisms and treatment of ventilatory pump failure might benefit a significant number of such newborns.Pediatr Pulmonol. 1994; 17:231–233.© 1994 Wiley‐Liss, Inc.
Expression of retinoic acid receptor genes in fetal and newborn rat lung
Authors: Grummer Mary A. , Thet Lyn A. , Zachman Richard D.
Published: March 2007

Lung differentiation and development are affected by vitamin A and its metabolites. One mechanism through which retinoids might exert their effects is through nuclear retinoic acid receptors (RAR). The gene expression profile of the RAR family (α, β, γ) has previously been determined in both the developing mouse embryo to 14.5 days gestation,28–30 and in the adult The purpose of this study was to determine the expression of the RAR genes during the period of gestation that results in the formation of the saccular lung stage. Total RNA was extracted from fetal lungs of Sprague‐Dawley rats at gestational days 17, 19,20, 21, and 22, and from 12‐hour‐old newborns for Northern hybridization. Two transcripts of RAR α mRNA (3.7 and 2.7 kb) were found at each time point. At day 17, the 2.7 kb RAR α mRNA was increased two‐fold or more than at any other time studied. At days 19–22 the levels of the 3.7 kb RAR α species were also lower than day 17 and newborn levels. One RAR p mRNA transcript (3.4 kb), present at all time points, was significantly higher in the newborn than on days 17–22. Expression of RAR γ mRNA could only be demonstrated by reverse transcriptase‐polymerase chain reaction. We speculate that the higher RAR (Y species at day 17 indicates a role for RAR α in the maintenance of the columnar epithelial cells of the glandular phase of lung development. The significant rise at birth of RAR β expression, after being low from days 17–22, suggests its relationship to completion of terminal saccule formation and preparation for subsequent alveolarization. Pediatr Pulmonol. 1994; 17:234–238. © 1994 Wiley‐Liss, Inc.
Cardiorespiratory and stress hormone responses during first dose surfactant administration in neonates with RDS
Authors: Chan O. , Moglia Bernadine A. , Reeves Inez V. , Kim Anna H. , Darrow Kimberly A. , Seaton John F. , Marks Keith H.
Published: March 2007

Our hypothesis was that surfactant instilled into the trachea, followed by body positioning maneuvers utilized to enhance drug distribution, could alter hemodynamic function and stimulate the release of catecholamines. We conducted a prospective randomized study designed to compare the immediate physiologic effects of the first dose of Exosurf® NeonatalTM (5 mL/kg; n = 16) or Survanta® (4 mL/kg; n = 18), when surfactant administration was standardized with strict adherence to drug company protocol. Physiologic variables were monitored continuously. Arterial blood gases (ABG) and plasma catecholamine concentrations were measured before, and 5 minutes after, surfactant administration. Both surfactants had an immediate effect on arterial oxygen saturation (S), partial pressure of oxygen in arterial blood (P), and oxygen index (Ol). The improvement in oxygenation after surfactant therapy was similar fn both groups. There was no significant difference in the mean umbilical arterial blood pressure(ABP) following surfactant therapy in both groups. High concentrations of plasma norepinephrine (reflecting activity of the sympathetic nerves) and epinephrine (a measure of secretion from the adrenal medulla) indicate that preterm infants with respiratory distress syndrome (RDS) prior to treatment mount a substantial stress response. The currently recommended techniques for instillation of surfactant appear not to trigger a significant further surge of plasma catecholamines or to acutely change mean ABP. Alternatively, it may be possible that the lack of response was because catecholamine release was already maximal. Pediatr Pulmonol. 1994; 17:246–249. © 1994 Wiley‐Liss, Inc.
Evaluation of a tidal expiratory flow index in healthy and diseased infants
Authors: Clarke Jane R. , Aston Hazel , Silverman Michael
Published: March 2007

Patterns of tidal respiratory flow have been shown to relate well to airway function in adults, and one epidemiological study in infants has demonstrated the value of the ratio of time to reach peak tidal expiratory flow to the total expiratory time (tpef/te) in predicting subsequent wheezing. The aim of this study was to evaluate tpef/te as a measure of lung function, by sequential observations over the first year, on a group of 22 healthy infants and on 32 infants with a history of mild recurrent lower respiratory illness (LRI), and by single observations on 20 infants with asthma and 20 with severe chronic lung disease of prematurity. We compared tpef/te measured in quiet, supine sleep (under sedation) through a face mask and pneumotachograph, with a measure of airway function, maximal flow at functional residual capacity (VmaxFRC), obtained from partial forced expiratory flow volume loops using the “squeeze” technique. In healthy infants tpef/te was significantly longer at 1 month than at 6 months (median values, 0.38 (95% CI, 0.3M.43) and 0.28 (95% CI, 0.26–0.33), respectively). Between 6 and 12 months tpef/te did not alter significantly and it was independent of VmaxFRC. Both tpef and te as well as their ratio varied with frequency of breathing over the first year of life, but not within each individual age band, due to the narrow spread of frequencies at each age. In assessing airway obstruction, tpef/te was less sensitive than VmaxFRC. There was no difference between healthy infants, those with LRI, and infants with asthma. Values outside the 95% CI for our control group of healthy infants were only seen in the group of infants with severe chronic lung disease of prematurity (median value, 0.16; 95% CI, 0.12–0.22), most of whom demonstrated expiratory flow limitation during tidal breathing. We found the tidal breathing index tpef/te to be an insensitive measure of airway function in infants, compared with VmaxFRC. Pediatr Pulmonol. 1994; 17:285–290. © 1994 Wiley‐Liss, Inc.
Bedside management of lung collapse in children on mechanical ventilation: Saline lavage — simulated cough technique proves simple, effective
Authors: Galvis Antonio G. , Reyes Gerardo , Nelson William B.
Published: March 2007

We report a simple, four‐step procedure for bedside treatment of infants on mechanical ventilation who have various degree of lung collapse unresponsive to conventional instillation of saline followed by chest percussion with endotracheal suctioning. The technique involves hyperoxygenation by bagging with 100% oxygen, deep endotracheal instillation of 0.25–0.5 mL/kg sterile saline, bagging with momentary inspiratory hold, followed by release of the hold and simultaneous forced exhalation and vibration to simulate cough, and endotracheal suctioning. This procedure was repeated three to five times on the affected side and at least once on the unaffected side; it resulted in notably improved lung expansion in 48 of 57 infants, documented by chest radiographs. The 57 infants included 48 (84%) whose chest radiographs showed airways occluded by mucus (“no air bronchograms”) and 7 (16%) whose chest radiographs showed patent airways (“air bronchograms”). The technique is less successful in the latter group of patients in whom material obstructing proximal and intermediate airways has already been removed or displaced to distal airways, or a parenchymal infection has developed. Pediatr Pulmonol. 1994; 17:326–330. © 1994 Wiley‐Liss, Inc.
“Click test”: Rapid diagnosis of the respiratory distress syndrome
Authors: Skelton Ruth , Jeffery Heather
Published: March 2007

Appropriate and early treatment with exogenous surfactant has clinical and economic benefits for neonates with pulmonary surfactant deficiency. In order to rapidly and reliably identify such neonates, we have evaluated the shake and click tests, biophysical tests of surfactant function, using 0.2 mL samples of tracheal (TA) and gastric aspirates (GA). Samples from 181 neonates with a gestational age range of 24–40 weeks were shaken with 95% ethanol. If bubbles formed (positive shake test) they were examined in air‐free water under a microscope. In a positive shake or click test, the bubbles rhythmically increase and then decrease in size, denoting the presence of active surfactant. The probability of the tests to predict clinical surfactant deficiency was analyzed. The latter was defined as respiratory distress syndrome or transient tachypnea of the newborn diagnosed by chest radiography and clinical criteria. The click test on TA from preterm infants was most accurate, with a 100% positive predictive value and specificity, and a 93% and 94% negative predictive value and sensitivity, respectively. These values for GA were 73%, 84%, 97%, and 95%. respectively. The test is quick, simple, inexpensive, reproducible, and unaffected by contamination with blood. The accuracy of this test on TA in diagnosing surfactant deficiency in neonates would permit early and optimal treatment with exogenous surfactant. When performed on GA, the test could aid decisions regarding transfer of neonates to tertiary level care. Pediatr Pulmonol. 1994; 17:383–389. © 1994 Wiley‐Liss, Inc.
Allotypes of α1‐antitrypsin in patients with cystic fibrosis, homozygous and heterozygous for deltaF508
Authors: Döring Gerd , Krogh‐Johansen Helle , Weidinger Sebastian , Høiby Niels
Published: March 2007

In cystic fibrosis (CF) neutrophil released serine proteinase activity may facilitate Pseudomonas aeruginosa lung colonization, leading to chronic infection. Since such activity is mostly controlled by α1‐antitrypsin (α1‐AT), we postulated that patients with CF carrying deficient α1‐AT variants might be at higher risk for P. aeruginosa acquisition and might reveal other phenomena, specific for serine proteinase activity. In 215 Danish patients with CF, homozygous (80%) or heterozygous (20%) for the major CF mutation deltaF508, α1‐AT variants were determined. Carriage of deficient α‐AT variants was correlated to an earlier onset of P. aeruginosa lung infection (P < 0.001), higher total IgG (P < 0.001), and P. aeruginosa‐specific serum antibodies (P < 0.0001). The two groups did not differ in lung function, probably due to intensive antimicrobial treatment. Pediatr Pulmonol. 1994; 18:3–7. © 1994 Wiley‐Liss. Inc.
Persistent wheezing and gastroesophageal reflux in infants
Authors: Eid Nemr S. , Shepherd Ross W. , Thomson Michael A.
Published: March 2007

We have evaluated the presence of gastroesophageal reflux (GER) and the effect of its treatment in 12 infants (mean age, 7 months; range, 4–11 months) with persistent wheezing not responding to bronchodilators and anti‐inflammatory asthma medications. All patients had GER on cineradiography and significant acid reflux on 24 hour pH monitoring (percentage of time pH < 14 ranged from 6.1 to 47%). All infants were initially treated with prokinetic agents and with receptor histamine antagonists in addition to aggressive pulmonary therapy. Six patients treated medically had substantially decreased use of asthma medications, completely discontinuing them within 2–4 months. Two patients, though significantly improved, require intermittent asthma therapy. Four patients responding poorly to GER and asthma treatment for 2 months to 2 years had fundoplications. These had an excellent outcome over 1–4.5 years follow‐up; only one patient required further asthma medications. Pulmonary function testing was done in six patients before and after 6–8 weeks of therapy indicating significant improvement in peripheral airflow: terminal flow/peak tidal expiratory flow (TEF25/PTEF), and percentage of total expiratory time to reach peak tidal expiratory flow (Tp/Te or Tme/Te).

Our experience suggests that evaluation for GER should be considered in infants with persistent wheezing. Aggressive medical and possibly surgical therapy for GER may resolve persistent wheezing.Pediatr Pulmonol. 1994; 18:39–44. © 1994 Wiley‐Liss. Inc.
A new device for ambulatory cough recording
Authors: Munyard Paul , Busst Carolyn , Logan‐Sinclair Ron , Bush Andrew
Published: March 2007

Nocturnal cough reporting on diary cards has been shown to be unreliable and inconsistent. Whether subjective reporting of daytime cough is equally unreliable remains unknown. We have, therefore, developed a new and easily portable device (RBC‐7) that records electromyographic (EMG) and audio cough signals for at least a 24‐hr period, with a capacity of over 48 hr. Additional information is obtained from electrocardiographic (ECG) signals, and from an accelerometer indicating the level of the subject's activity. The RBC‐7 can be set up with the aid of a notebook computer at the subjects home, school or workplace. Initial studies utilizing a prototype device were performed to determine the optimal position of the EMG leads and the microphone. The optimal position for the EMG leads was determined as the positive electrode in the sixth intercostal space (ICS) in the midclavicular line on the left, the negative electrode in the same position on the right, and the reference electrode in the midline over the abdomen. This position was shown to give the highest EMG voltages and the greatest difference in voltages between cough and other signals. The optimal microphone position for signal strength and comfort was over the first ICS, either right or left, close to the sternum. Recordings were performed simultaneously in 20 subjects with conventional tape recorders and the multiparametric cough monitoring system (RBC‐7). Conventional tape recordings limited the duration of the studies due to the inherent restrictions. No significant difference in the number of single coughs recorded by each system was detected (correlation coefficient = 0.996). The RBC‐7 offers a unique opportunity to obtain objective information on cough in ambulatory subjects over at least a 24‐hr period, and to relate cough to time, activity and heart rate, while normal activities are pursued.Pediatr Pulmonol. 1994;18:178–186. © 1994 Wiley‐Liss, Inc.
Effect of dexamethasone and oxygen exposure on neonatal rat lung retinoic acid receptor proteins
Authors: McMenamy Kandi R. , Anderson Marni J. , Zachman Richard D.
Published: March 2007

Retinol deficiency in animal models results in histopathologic airway changes that appear similar to those found in human premature infants with bronchopulmonary dysplasia (BPD). Dexamethasone (DEX), a steroid now often used in the treatment of BPD, might potentially affect lung vitamin A homeostasis since it alters serum and liver retinoid stores in certain models.

Our objective was to determine the effect of DEX on neonatal rat lung retinoid status and the binding of retinoic acid (RA) to cytosolic and nuclear receptor proteins. We examined this effect both in room air and when the animals breathed 95% oxygen (O2)

Twenty‐four 1‐day‐old rat pups received either 1 μg/g DEX subcutaneously, an equal volume of normal saline (NS) subcutaneously at 0 (start experiment time), 24, and 48 hours, or no injection at all, and were sacrificed at 72 hours. Twelve rats in each treatment group were housed in room air and 12 in each group were exposed to 95% O2, for the 3 day period. Lung and liver were analyzed for retinyl palmitate (RP). Nuclear retinoic acid receptor (RAR) and cellular retinoic acid binding protein (CRABP) were measured by specific binding assays.

DEX decreased liver RP by 33–55% and rat pup lung RP by over 60%; it also decreased lung RAR binding (mean dpm/μg protein ± SEM) in both room air and oxygen groups: Air (11.2 ± 1.0) vs. Air/DEX (4.6 ± 1.3, n = 6; P <0.01), and O2, (18.2 ± 0.6) vs. O2/DEX (3.2 ± 0.6, n = 6; P <0.001). Binding of RAR was higher in O2‐ vs. air‐exposed pups (18.2 ± 0.6, n = 6 vs. 11.2 ± 1.0, n = 5, P <0,001). While CRABP binding in DEX‐treated neonatal pup lungs was decreased in both air/DEX vs. air and O2/DEX vs. O2 exposed groups, the decrease did not reach significance. However, the combination of O2/DEX significantly decreased CRABP binding (O2DEX, 30 ± 13, n = 3) when compared with air (109 ± 13, n = 5) and air/saline (133 ± 13, n = 6) (P <0.05). Binding of CRABP was also significantly lower in O2‐exposed neonatal pup lungs (55 ± 10, n = 4) than those exposed to air (109 ± 13, n = 5)

This is the first report of DEX decreasing RP stores in neonatal rat lung and liver. We speculate that in sick premature infants receiving DEX, retinoids are mobilized from storage tissues to be utilized by tissue in need, such as during injury repair. This work also demonstrates a new possible interaction mechanism between DEX and retinoids at the functional level of RA binding proteins; DEX lowered RAR and CRABP binding activity.Pediatr Pulmonol. 1994;18:232–238. ©1994 Wiley‐Liss, Inc.
Exosurf rescue surfactant improves high ventilation‐perfusion mismatch in respiratory distress syndrome
Authors: Billman Daniel , Nicks Joanne , Schumacher Robert
Published: March 2007

Objective: To assess ventilation/perfusion (V̇A/Q̇) mismatch of the high type, following rescue surfactant therapy for respiratory distress syndrome. Hypothesis: Surfactant therapy reduces such mismatch. Design: Randomized, double‐blind, placebo‐controlled study, assessing V̇A/Q̇ with the arterial‐alveolar difference of CO2 tension c. This difference was determined with capnometry and arterial blood gases, using the equation: (P(a‐A)CO2) equals arterial CO2 minus alveolar CO2 partial pressure. Setting: A level III nursery. Patients: Ten intubated infants with respiratory distress syndrome. Intervention: Infants were randomized to each receive two doses of surfactant or two doses of air placebo. Results: P(a‐A)CO2 improved after surfactant and worsened after placebo (P = 0.0021), comparing slopes of 12‐hr regression lines. A similar pattern occurred with oxygenation. These changes in P(a‐A)CO2 and in oxygenation were minimally correlated within the surfactant group. Conclusion: Exosurf rescue surfactant reduced V̇A/Q̇ mismatch of the high type, over several hours.Pediatr Pulmonol. 1994;18:279–283 © Wiley‐Liss, Inc.
High frequency chest compression therapy: A case study
Authors: Butler Sarah , O'Neill Brenda
Published: March 2007

A new device, the ThAIRapy® Bronchial Drainage System, enables patients with cystic fibrosis to self‐administer the technique of high frequency chest compression (HFCC) to assist with mucociliary clearance. We review the literature on HFCC and outline a case study of a patient currently using the ThAIRapy® Bronchial Drainage System. While mucociliary clearance and lung function may be enhanced by HFCC therapy, more research is needed to determine its efficacy, cost benefits, and optimum treatment guidelines. Although our initial experience with the patient using this device has been positive, we were unable to accurately evaluate the ThAIRapy® Bronchial Drainage System. © 1995 Wiley‐Liss, Inc.
Cardiorespiratory adaptation during sleep in infants and children
Authors: Gaultier Claude
Published: March 2007

The cardiorespiratory control system undergoes functional maturation after birth. Until this process is completed, the cardiorespiratory system is unstable, placing infants at risk for cardiorespiratory disturbances, especially during sleep. The profound influence of states of alertness on respiratory and cardiac control has been the focus of intense scrutiny during the last decade. The effects of rapid‐eye movement (REM) sleep on various mechanisms involved in cardiorespiratory control are of particular significance during the postnatal period since newborns spend much of their time in this sleep state. In fullterm newborns, REM sleep occupies more than 50% of total sleep time, and this percentage is even greater in preterm newborns. From term to six months of age, the proportion of REM sleep decreases.2 Since respiratory and cardiac disturbances are known to occur selectively during REM sleep, the predominance of REM sleep may be a risk factor for abnormal sleep‐related events during early infancy.3 Awareness of these developmental changes in sleep patterns is important for clinicians dealing with problems such as apparent life‐threatening events (ALTE), sudden infant death syndrome (SIDS), and/or cardiorespiratory responses to respiratory disorders. Our current understanding of respiratory and cardiac control rests mainly on studies conducted during the first months of life. There is a paucity of data on late infancy and early childhood. The present paper will review available data on how sleep affects 1) ventilatory mechanics, in particular of the upper airways and the chest wall; ventilation and apnea; gas exchange; chemoreceptor function; and arousal responses; 2) changes in heart rate and heart rate variability, and the occurrence and mechanisms of bradycardia. © 1995 Wiley‐Liss, Inc.
Gender differences in lung growth
Authors: Hibbert M. , Lannigan A. , Raven J. , Landau L. , Phelan P.
Published: March 2007

Annual measurements of lung volumes and forced expiratory flows were made in 281 boys and girls from 8 to 12 years and in another cohort of 287 from 12 to 20 years to measure longitudinal lung growth. Gender differences in growth of lung function were documented, with girls generating greater volume‐standardized maximal expiratory flows until age 18.5 years. Beyond that age boys generated higher expiratory flows in proportion to total lung capacity (TLC). There was a time lag of up to 1 year between the age of peak growth velocity in lung volume and peak growth velocity in height. Age at peak growth in flow lagged another year behind that in volume. This was noted more in boys than girls. Dysanaptic lung growth was found with differing rates of growth of maximal expiratory flow compared with TLC or vital capacity (VC). © 1995 Wiley‐Liss, Inc.
Spirometric reference values for white European children and adolescents: Polgar revisited
Authors: Quanjer Ph. H. , Borsboom G. J. J. M. , Brunekreef B. , Zach M. , Forche G. , Cotes J. E. , Sanchis J. , Paoletti P.
Published: March 2007

We analyzed six spirometric data sets collected in the Netherlands, Austria, the United Kingdom, Spain, and Italy. The objectives were to establish whether (1) it was possible to describe spirometric indices from childhood to adulthood, taking into account the adolescent growth spurt, and (2) there are systematic differences in ventilatory function between children and adolescents in different parts of Western Europe. The study comprised 2,269 girls and 3,592 boys, aged 6–21 years. The range in standing height was 110–185 in girls, 110–205 in boys. The model applicable to all data sets was In FVC or In FEV1 = a + (b + c · A)· H, where H = standing height and A = age; this model prevents the phase shift between the adolescent growth spurt in length and lung volume from leading to an age‐dependent bias in predicted values. There was surprising agreement between most of the data sets; systematic differences are probably due to technical factors arising from ATPS‐BTPS corrections and from defining the end of breath with pneumotachometer systems. Taking those into account, prediction equations for FVC, FEV1, and FEV1%FVC were developed with “lower limits of normal” which should be applicable to children and adolescents of European descent. It is proposed that the approach of analyzing available data sets should also be applied to other ventilatory indices, data collected in adults and elderly subjects, or in other ethnic groups, and that an international data base be set up to that end. © 1995 Wiley‐Liss, Inc.
The Yentl syndrome in childhood asthma: Risk factors for undertreatment in Swiss children
Authors: Kühni Claudia E. , Sennhauser Felix H.
Published: March 2007

Recent prevalence data for childhood asthma in Switzerland suggest a substantial underdiagnosis which seems to be more pronounced in girls. We further analysed our data trying to specify risk factors for underdiagnosis and undertreatment. Our special interest was focused on female sex as there is evidence for a sex‐dependent diagnosis and treatment of chronic disease in adults, called the Yentl syndrome. The data are derived from a parent completed questionnaire survey of a stratified cluster sample of schoolchildren aged 7, 12, and 15 years. Besides the 12 months prevalence of asthma symptoms and bronchodilator treatment, the lifetime prevalence of an asthma diagnosis was noted. With a response rate of 97%, a total of 4353 completed questionnaires were analysed. While age was not associated with undertreatment (except for exercise‐induced symptoms in adolescents), the lack of a formal diagnosis of asthma and atypical asthma symptoms other than wheeze such as chronic night cough were confirmed as significant risk factors for undertreatment. Of all boys reporting asthma symptoms 31% received bronchodilator treatment compared with only 15% of the symptom‐reporting girls (P < 0.001). For all particular asthma‐related symptoms (except wheeze), significantly more boys than girls (approximately double) received treatment. The physiological and psychological bases for these findings are discussed and suggest that gender is an important risk factor for under‐diagnosis and under‐treatment of asthma. Our research indicates that the Yentl syndrome may exist for childhood asthma. © 1995 Wiley‐Liss, Inc.
Validation of the phase angle technique as an objective measure of upper airway obstruction
Authors: Hammer J. , Newth C. J. L. , Deakers T. W.
Published: March 2007

Thoraco‐abdominal asynchrony (TAA) during upper airway obstruction (UAO) in small children can be documented by phase angle analysis of the Lissajous figure from the output of a noncalibrated respiratory inductance plethysmograph. Phase angle measurements have not been related to levels of inspiratory resistance, nor to the effect of breathing a 79% helium‐21% oxygen mixture (heliox) during inspiratory resistance. We examined the effects of graded inspiratory loading (5–1000 cm H2O/L/sec) on TAA as measured by phase angle in 10 male, anesthetized, and intubated Rhesus monkeys, breathing room air and heliox. Phase angles increased with inspiratory loading from a baseline value of 22 ± 3° to 165 ± 8° at 1,000 cm H2O/L/sec resistance and correlated significantly with the level of inspiratory loading (r = 0.82). Endtidal carbon dioxide PETCO2 increased from 39 ± 1 to 49 ± 3 mm Hg at the highest load, but correlated only weakly with phase angle measurements (r = 0.60) and the level of inspiratory loading (r = 0.56). By changing to heliox breathing at the highest tolerated resistance, PETCO2 dropped significantly from 49 ± 3 to 40.5 ± 4 mmHg (P < 0.001) with no significant change in phase angles: 169 ± 13° and 165 ± 8°, respectively (P > 0.05). We conclude that heliox therapy for acute alveolar hypoventilation during UAO improves ventilation, but does not decrease TAA at high inspiratory resistance. Continuous monitoring of the relative changes in phase angles is useful to observe the severity of UAO in the early stages. However, phase angle analysis does not predict the development of hypercapnia secondary to inspiratory load. Pediatr Pulmonol. © 1995 Wiley‐Liss, Inc.
Preservation of pulmonary function in the ventilated neonatal piglet with normal lungs
Authors: Easa David , Finn Kuuleialoha C. , Balaraman Venkataraman , Sood Sneha , Wilkerson Stephen , Takenaka Wayne , Mundie Thomas G.
Published: March 2007

Little attention has been focused on the progressive pulmonary deterioration which occurs in mechanically ventilated infants with normal or mildly abnormal lungs. We hypothesized that lung function would deteriorate over a 24‐hr period in anesthetized neonatal piglets with normal lungs mechanically ventilated at 2 cm H2O PEEP (2PEEP group). We further hypothesized that an intermittent lung inflation procedure consisting of 15 out of 60 min of increasing lung distention (4,8,12 cm H2O PEEP), with the remaining 45 min at 2 cm H2O PEEP (Inflation group) would prevent this deterioration in lung function, similar to piglets mechanically ventilated continuously at 6 cm H2O PEEP (6PEEP). Results indicate that 2PEEP piglets experienced progressive deterioration in lung function, including dynamic lung compliance (‐42%) and lung resistance (+55%). In contrast, Inflation piglets and GPEEP piglets had no deterioration in lung function. Hemodynamics were similar between groups, although they were the most stable in the 6PEEP group. Histopathological changes were not significantly different. We conclude that (1) prolonged mechanical ventilation at 2 cm H2O PEEP in neonatal piglets resulted in progressive deterioration in pulmonary function, (2) intermittent lung inflation or continuous 6 cm H2O PEEP prevented deterioration, and (3) functional changes occurred without changes in histopathology. Lung inflation strategies other than PEEP can be used to prevent deterioration in lung function which accompanies prolonged mechanical ventilation in anesthetized nonspontaneously breathing piglets with normal lungs. © 1995 Wiley‐Liss, Inc.
Pulmonary hypertension in respiratory distress syndrome
Authors: Golan A. , Zalzstein E. , Zmora E. , Shinwell E. S.
Published: March 2007

Pulmonary hypertension was associated with nonresponse to surfactant in six premature infants with respiratory distress syndrome. The diagnosis was suspected on the basis of a discrepancy between the X‐ray findings and the severity of the clinical status as reflected by hypoxia despite maximal ventilatory support. The diagnosis of pulmonary hypertension was made by pre‐ and postductal oxygen saturation differences or by echodoppler cardiography, showing suprasystemic right ventricular pressures or right to left shunts through a patent foramen ovale or the ductus arteriosus. The response to surfactant was quantified by the arterial/alveolar (a/A) ratio difference before and 1 hr after therapy (“delta a/A ratio”); the delta a/A ratio was 0 ± 0.01, which indicates a nonresponse. A single dose of 1 mg/kg tolazoline was administrated and the response assessed by a/A difference. A delta a/A ratio of 0.11 ± 0.11 (range 0.02‐0.32) represented a dramatic response and enabled oxygenation in these severely ill infants. No significant side effects were observed. We conclude that pulmonary hypertension may be an important and reversible condition in certain cases of respiratory distress syndrome and has to be considered in infants who do not respond to surfactant. © 1995 Wiley‐Liss, Inc.