bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractWhen 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

AbstractRespiratory 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

AbstractThe 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

AbstractHigh 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

AbstractRecent 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

AbstractEnd‐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

AbstractThe 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

AbstractObjective: 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

AbstractLung 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

AbstractOur 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

AbstractPatterns 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

AbstractWe 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

AbstractAppropriate 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

AbstractIn 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.