bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of smooth muscle tone and longitudinal tension on the collapsibility of immature airways
Authors: Penn Raymond B. , Wolfson Marla R. , Shaffer Thomas H. 
Published: March 2007

AbstractMechanical properties and pressure‐flow relationships of tracheae excised from very premature lambs were studied in a plethysmograph. Control (Group 1) data revealed the tracheae to be extremely compliant, collapsible airways, with an inflation compliance (Si) of 0.033 (±0.004 SE) mmHg−1, collapsing compliance (Sc) of 0.026 (± 0.001 SE) mmHg−1, and pressure‐flow relationships similar to those of a Starling resistor. Acetylcholine administration (Group II) lowered both Si, 0.026 (± 0.003 SE) mmHg−1 and Sc, 0.022 (± 0.003 SE) mmHg−1, asdid longitudinal stretch (Group III): Si, 0.021 (±.003 SE) mmHg−1, and Sc, 0.017 (± 0.002 SE) mmHg−1. Alterations in tracheal collapsibilty were also evidenced by significant reductions in resistance to airflow when the tracheae were subjected to compressive forces. Altering both smooth muscle tone (acetylcholine administration) and longitudinal length simultaneously (Group IV) produced results similar to those obtained for Group III. These data help to define the functional characteristics of immature airways and may provide insight for more effective clinical management of the premature infant.
Lung volume changes during histamine‐induced bronchoconstriction in recurrently wheezy infants
Authors: Maxwell David L. , Prendiville Anne , Rose Alison , Silverman Michael 
Published: March 2007

AbstractRespiratory inductance plethysmography was used to estimate changes in functional residual capacity (FRC) in seven recurrently wheezy infants undergoing histamine challenge. Inhalations of normal saline and doubling concentrations of histamine were given up to and including the provoking concentration (PC) that caused a significant fall in maximum flow at FRC (Vmax FRC) as measured using the inflatable jacket technique. Below the PC histamine in general caused small increases in FRC [9.4 ± 7.6 ml (mean ± SD) at half the provoking concentration]. However, larger increases were seen at the provoking concentration (26.6 ± 15.6 ml). Inspection of flow‐volume curves obtained before and after the larger changes in FRC suggested that the reduction in airflow measured by the change in Vmax FRC was underestimated.
Update on pediatric chest imaging
Authors: Eggleston Daniel E. , Slovis Thomas L. , Watts Frederick B. 
Published: March 2007

AbstractEven in the high‐technology medical imaging arena, the decision of how to first image pediatric chest disease is quite simple: by plain chest radiograph, including frontal and lateral views. The diagnosis can often be made or suggested on the basis of these films or with other basic imaging procedures, such as fluoroscopy or esophagram. From this point onward the decision how to proceed with further imaging such as ultrasound, computed tomography, nuclear medicine imaging, or magnetic resonance imaging, will depend on the probability of gaining further helpful information. Beginning with a concise differential diagnosis allows one to proceed in a logical manner through the diagnostic work‐up in a timeeffective and cost‐effective manner. One must keep in mind that in some cases the diagnosis cannot be made radiologically and must be left to the pathologist. In these cases the work‐up should end when no further progress is possible toward making the diagnosis. In the pediatric age group, one should always strive to limit the amount of unnecessary radiation exposure.
Recruitment of intercostal muscle activity during hypercapnia in kittens
Authors: Watchko Jon F. , Klesh Kenneth W. , O'Day Terrance L. , Guthrie Robert D. 
Published: March 2007

AbstractLittle is known about the respiratory behavior of the intercostal muscles within a neonatal and developmental context. We, therefore, examined intercostal muscle electromyographic (EMG) activity in kittens (1 month old, n = 8; 2 months old, n = 7) during eupnea and heightened respiratory drive induced by hypercapnia. The kittens were anesthetized with halothane (1.25–1.50%) at comparable minimum alveolar concentrations and were studied in the prone position during an acute exposure to hyperoxic hypercapnia (8% CO2, 50% O2, balance N2) for 7 min. We recorded EMG activities from bipolar electrodes embedded in the intercostal (dorsolateral thorax, 4th‐5th interspace) (EMGic) and costal diaphragm (EMGdi) muscles. Peak moving time average EMG measurements served as our index of muscle activity. Phasic inspiratory EMGic activity was present during eupnea in all animals. EMGic and EMGdi increased significantly above baseline levels during hypercapnic exposure with the increase in EMGic (133 ± 27%) being comparable to that observed in EMGdi (141 ± 28%) (P = 0.40). No differences in EMGic (P = 0.64) or EMGdi (P = 0.88) recruitment were noted between age groups. These data indicate that hypercapnia augments intercostal muscle EMG activity in kittens and suggest that such activity parallels costal diaphragmatic EMG recruitment. We conclude that EMGic recruitment is a frequent respiratory phenomenon associated with hypercapnically stimulated diaphragmatic muscle activity in kittens. We speculate that intercostal muscle recruitment stabilizes the compliant chest wall of the newborn and helps sustain inspiratory force generation during stimulated breathing.
Alveolar data in healthy, awake neonates during spontaneous ventilation: A preliminary investigation
Authors: Lagneaux Denise , Mossay Christian , Geubelle Fernand , Christiaens Georges 
Published: March 2007

AbstractA computerized method for the measurement of alveolar ventilation (VA) and the mean alveolar partial pressures of CO2 and O2 is described and tested in healthy, awake fullterm (FT) newborns and preterm (PT) infants (postnatal age 40 days). This study emphasizes the technical pitfalls generally encountered when dealing with very small infants. A sensitive pneumotachograph with a small dead space volume and a low‐flow sampling system for the gas analyzer are minimum requirements. Under these technical conditions, the major problem is the scanning time of the mass spectrometer (50 Hz), which fixes the time constant, as well as the digitization sampling rate of the gas signals. This rate was not sufficient when the respiratory rate was above 90 min−1. As critical visual evaluation of each breath is required, fully automatic access to mean alveolar data is not possible.The mean dead‐space volume in both FT and PT infants was 2 ml. kg‐1, with a VD/VT ratio of 0.3. The mean alveolar point was 2/3 VT, as found in adults. When expressed as ml. min−1. kg−1, VA appeared to be higher than in other studies, but related to the metabolic requirements. (VCO2 = 7.8 ± 0.2 ml. min−1. kg−1 and VO2 = 8.0 ± 0.2 ml. min−1. kg−1), in accordance with the state of vigilance of the neonates. Indeed, the PACO2 values, which depend on the ratio VCO2/VA, are in agreement with the values of PaCO2 generally considered normal in healthy newborns over 1 week of age.The values obtained for small infants indicated a highly significant statistical difference between the end‐tidal and the corresponding mean alveolar values of PCO2 and PO2. It appears that the use of PetCO2 and PetO2 for the alveolar partial pressures produces only a rough approximation of the real values.
Passive total respiratory system compliance and gas exchange in newborns with hyaline membrane disease
Authors: Dreizzen E. , Migdal M. , Praud J.P. , Saby M.A. , Chambille B. , Dehan M. , Gaultier C. 
Published: March 2007

AbstractPassive total respiratory system compliance (CRS) and gas exchange measurements were performed in nine newborns during the course of hyaline membrane disease. None of the subjects presented bronchopulmonary dysplasia at follow‐up investigations. Gestational age ranged from 29 to 37 weeks. CRS was measured by the multiple occlusion technique. Gas exchange parameters were the fraction of inspired oxygen concentration (FIO2) and the arterial/alveolar ratio for oxygen (a/Ao2 ratio). In each subject four tests were performed: test 1 during the first day of life; test 2 during the second day of life; test 3 between the fourth and the seventh days of life; test 4 after extubation. CRS/BW (CRS normalized for body weight) was not statistically different at tests 1–3, but it significantly increased (P < 0.001) between tests 3 and 4. FIO2 and a/Ao2 ratio presented no statistical difference at tests 1–2 but several significant differences were noted thereafter; F102 decreased significantly (P < 0.001) when results from tests 2 and 3 were tabulated. The a/Ao2 ratio increased significantly between tests 2 and 3 (P < 0.001), and a further significant increase (P < 0.01) was also noted when results obtained during tests 3 and 4 were compared. A significant relationship existed during the evolution of the disease between CRS/BW and gas exchange parameters (FIO2 and a/Ao2 ratio) (P < 0.01), but gas exchange improved earlier than lung mechanics.
Long‐term tobramycin aerosol therapy in cystic fibrosis
Authors: Steinkamp Gratiana , Tümmler Burkhard , Gappa Monika , Hardt Horst Von Der , Potel Jürgen , Albus Anne , Döring Gerd 
Published: March 2007

AbstractThe long‐term efficacy and safety of aminoglycoside aerosol therapy for Pseudomonas aeruginosa colonization/infection in cystic fibrosis has not been fully investigated. In the present study, 14 patients with cystic fibrosis, ages 8–19 years (mean: 13.3 years), received tobramycin aerosol therapy for a mean duration of 20 months. Eighty milligrams of a tobramycin solution were inhaled twice daily after physiotherapy via a jet nebulizer. After 1 year, weight for height increased significantly by 2.9% of the predicted normal, and the Kraemer clinical score increased by 2.1 points (P <0.05). The frequency of hospital admissions decreased from 2.0 to 1.3 per patient, respectively, during the years before and after the study onset. The antibody response to P. aeruginosa elastase, exotoxin A, and alkaline phosphatase showed a reduction in serum titers against one or more enzymes in eight patients. The best long‐term results after 12–38 months of treatment were obtained in moderately ill children. No evidence of ototoxicity or renal damage was observed. Although intermittent bacterial resistance occurred in five patients after 10–21 months of tobramycin inhalation, this was not associated with clinical deterioration. The study demonstrates the safety and clinical efficacy of long‐term tobramycin aerosol therapy. Double‐blind studies with larger patient cohorts are required to determine the value of aminoglycoside inhalation as an adjunct to the established therapeutic regimens.
Effect of chest wall oscillation on mucus clearance: Comparison of two vibrators
Authors: Rubin Eben M. , Chapman Gillette A. , Eldridge Mungen , Wanner Adam , Scantlen Gregory E. , Menendez Rogelio 
Published: March 2007

AbstractThis study was designed to investigate the effect of an experimental low‐energy chest wall oscillator and of a commercial chest percussor on central airway mucociliary clearance. Five normal dogs were anesthetized, intubated, and placed supine in a trough to which the oscillator or percussor was mounted. Tracheal mucus velocity (TMV) was measured by radiopaque particle or charcoal spot movement. The commercial percussor (a fixed sinusoidal device) used at its minimum frequency of 40 Hz, produced a mean (± SE) maximum expiratory flow rate of 0.25 ± 0.04 L/sec at the airway opening, and had no measurable effect on TMV. The experimental oscillator, when operated at a level sufficient to generate flows of 2–3 L/sec, and with an unbiased 13‐Hz sine wave (estimated energy, 150 W), increased mean TMV to 204 ± 13% of control (P <0.003): the percent increase was independent of baseline TMV. We conclude that moderate oscillatory power applied to the chest wall can enhance mucus clearance in central airways, but that currently available commercial percussors may not meet the mechanical requirements for this effect.
Accuracy of two wavelength pulse oximetry in neonates and infants
Authors: Praud J.‐P. , Gaultier C. L. , Carofilis A. , Lacaille F. , Dehan M. , Bridey F. 
Published: March 2007

AbstractIn 60 neonates (gestational age, 26.5–40 weeks; postnatal age, 1–14 days) and in 11 infants (gestational age, 26–33 weeks; postnatal age, 4.5–38 weeks), the accuracy of two wavelength pulse oximetry was examined. A total of 112 comparisons between transcutaneous pulse oximetry saturation (StcO2, NELLCOR™ N‐100) and arterial oxygen saturation (SaO2, OSM2 RADIOMETER™) were obtained. SaO2 ranged from 80 to 100%. Criteria for comparison between StcO2 and SaO2 were standardized: patients in behavioral state 1, StcO2 stable for 2 min, and arterial samples drawn from an indwelling arterial line. StcO2 was significantly related to SaO2 (P < 0.01), but the difference, StcO2 ‐ SaO2, significantly increased when SaO2 decreased [StcO2 ‐ SaO2 (%) = ‐0.39 SaO2(%) + 37.95; r = ‐0.64, P <0.01]. No significant relationship was found between StcO2 ‐ SaO2 and either bilirubinemia (range, 5–222 m̈mol/L) or fetal hemoglobin (HbF) (range, 12–95%). We conclude that StcO2 overestimates SaO2 when SaO2 decreases, and this overestimation is not due to high levels of bilirubin or HbF.
Viral and Mycoplasma pneumoniaepneumonias in school‐age children: Three‐Year follow‐up of respiratory function
Authors: Todisco Tommaso , de Benedictis Fernando M. , Dottorini Maurizio 
Published: March 2007

AbstractWe studied the evolution of respiratory function during and for 3 years after the acute onset of viral and Mycoplasma pneumoniaepneumonias in 13 school‐age children. A mixed type transient ventilatory defect (restrictive and obstructive, but mainly restrictive) with large and small airway involvement was observed during the acute phase of the pneumonias. Residual small airway involvement was found over the next 12 months, but no pulmonary function abnormalities were present after 3 years. At that time, one of the 13 subjects displayed bronchial hyperreactivity to distilled water mist challenge.The authors concluded that viral and Mycoplasma pneumoniaepneumonia in previously healthy school‐age children does not cause impaired lung function in later childhood.
Bronchial reactivity in infants in acute respiratory failure with viral bronchiolitis
Authors: Koumbourlis Anastassios C. , Mutich Rebecca L. , Motoyama Etsuro K. , Mallory George B. , Nakayama Don K. 
Published: March 2007

AbstractAirway reactivity and the effects of bronchodilators in infants are controversial. We studied the response to bronchodilator treatment in 14 mechanically ventilated infants (mean age, 2.74 months; range, 0.6–5.9) in respiratory failure caused by respiratory syncytial virus (RSV)‐associated bronchiolitis. Sixteen infants without lung disease, undergoing elective surgery, provided normal values. Maximum expiratory deflation flow‐volume (DFV) curves were produced by manual inflation of the lungs with an anesthesia bag to a predetermined static airway pressure followed by rapid deflation with a negative airway pressure before and after administration of bronchodilator. At baseline, the bronchiolitis group had a forced vital capacity (FVC) of 34.5 ± 3.6 ml/kg compared with 41.8 ± 1.5 ml/kg in the normal group; maximum expiratory flow rate at 25% of FVC (MEF25) was 10.2 ± 2.0 ml/kg/s compared with 27.3 ± 2.0 ml/kg/s in the normal group. The clinical and radiologic impression was severe lower airway obstruction and air trapping. After administration of bronchodilator, FVC did not increase significantly, but MEF25isov increased by over 30% in 13 of 14 infants. Mean MEF25increased by 148 ± 43.2% to 21.7 ± 3.9 ml/kg/s (P< 0.01). These findings indicate that during the acute phase of severe RSV‐positive bronchiolitis most infants have airway reactivity that responds positively to bronchodilator treatment.
Reliable salbutamol administration in 6‐ to 36‐month‐old children by means of a metered dose inhaler and aerochamber with mask
Authors: Conner W. T. , Dolovich M. B. , Frame R. A. , Newhouse M. T. 
Published: March 2007

AbstractA double‐blind study was performed to demonstrate that bronchodilator can be administered reliably to infants and children under 3 years of age from a metered‐dose inhaler (MDI) by means of an economical valved aerosol‐holding chamber device (Aerochamber)® fitted with a mask. Symptoms of cough and breathlessness were compared for two 1‐week crossover periods with the child either taking active drug or placebo. The MDI and Aerochamber with mask is an effective delivery system for respiratory therapy in these young children.
Periodic breathing parameter values depend on specific pneumogram scoring criteria
Authors: Glotzbach Steven F. , Tansey Patricia A. , Baldwin Roger B. , Ariagno Ronald L. 
Published: March 2007

AbstractPeriodic breathing (PB) has been related to both normal and pathologic respiratory system control in infants. However, comparison of the results of separate studies has been limited by the variability in procedures used by different investigators to quantify PB. In this study we scored 15 24‐hr impedance pneumograms using the criteria of Parmelee et al. (Neuropediatrie 3:294–304, 1972), Christova‐Gueorguieva (Biology of the Neonate 44:325–332, 1983), and Curzi‐Dascalova, Kelly and Shannon (Pediatrics 63:355–360, 1979) and analyzed the resulting differences in several commonly used PB parameters. Scoring criteria consistently and significantly influenced three PB parameters: the %PB, number of episodes of PB/100 min recording time, and mean duration of PB episode length showed average changes of 74%, 179%, and 36%, respectively, when the methods with the most extreme differences were compared. In contrast, the duration of the longest episode of PB showed no significant change as a function of scoring criteria. Awareness of the particular method of PB scoring is therefore essential in interpreting PB parameter values. Pediatr Pilmonol. 1989; 7:18‐21.
Measurement of lung volumes during active and quiet sleep in infants
Authors: Beardsmore Caroline S. , Macfadyen Una M. , Moosavi S. Shakeeb H. , Wimpress Stephen P. , Thompson John , Simpson Hamish 
Published: March 2007

AbstractThe question of whether functional residual capacity (FRC) falls in infants during active sleep has been clouded by studies using different subject groups and techniques for measurements of lung volume and determination of sleep state. Twenty healthy full‐term infants within the first week of life participated in the present study. Neurophysiological and behavioral criteria were used to define sleep state, and measurements of FRC were made using a specially constructed closed‐circuit helium dilution system. Regularity of respiration was recorded using magnetometers on the chest and a modified respirator monitor. Results showed that no significant changes in FRC occurred, related either to sleep state or to regularity of respiration. In addition, we failed to detect any differences in FRC between the sexes. Pediatr Pilmonol. 1989; 7:71–77.
Periodic breathing in preterm infants: Influence of bronchopulmonary dysplasia and theophylline
Authors: Glotzbach Steven F. , Tansey Patricia A. , Baldwin Roger B. , Ariagno Ronald L. 
Published: March 2007

AbstractPeriodic breathing (PB) has been studied extensively in both normal term infants and term infants presumed to be at high risk for sudden infant death syndrome (SIDS); however, little is known about the incidence and significance of PB in preterm infants. Twenty‐four hour impedance pneumograms were obtained from 108 preterm infants prior to their discharge from the nursery and four PB parameters (%PB, No. of episodes of PB/100 min, mean duration of PB episode length, and duration of the longest episode of PB) were quantified in each recording. Control infants who were asymptomatic for apnea had the highest PB parameter values (%PB, 12.0; No. episodes/100 min, 8.6; mean duration, 1.2 min; and longest episode, 7.3 min); infants with bronchopulmonary dysplasia (BPD) showed dramatic decreases in all PB parameters, with a median %PB of 1/16 of the control population. Theophylline use was associated with a significant decrease in PB parameter values only in infants without BPD. Central apneas >15 s did not vary significantly as a function of BPD, theophylline, or postconceptional age. We conclude that the clinical status of preterm infants significantly influences PB parameter values and must be taken into account in the interpretation of pneumograms, for decision‐making about home cardiorespiratory monitoring, and in assigning risk for SIDS. Pediatr Pilmonol. 1989; 7:78–81.
Branhamella catarrhalis bronchopulmonary isolates in PICU patients
Authors: Kasian Gordon F. , Shafran Stephen D. , Shyleyko Elizabeth M. 
Published: March 2007

AbstractBranhamella catarrhalis is commonly considered a respiratory commensal but has recently been implicated as a pathogen, particularly in adults. Over a 28 month period, B. catarrhalis was isolated from bronchopulmonary secretions of 14 PICU patients with acute respiratory infections.Twelve patients had pneumonia and two had tracheitis. The mean age was 3.5 years. Seven patients had chronic cardiopulmonary disease including two who were immunosuppressed. Three had an acute underlying condition and four had no complicating medical problem.Polymorphs and Gram‐negative diplococci on Gram stain were found in respiratory secretions of all patients. Twelve of 14 isolates produced β‐lactamase, and six patients had a second potentially pathogenic bronchopulmonary isolate. All patients were treated for B. catarrhalis infection and none died.When isolated in pure culture from bronchopulmonary secretions in symptomatic patients, B. catarrhalis should be considered a pathogen. When isolated in mixed culture, its pathogenic role is uncertain. We conclude that B. catarrhalis can be a bronchopulmonary pathogen in critically ill children with otherwise normal cardiopulmonary function as well as in those with chronic cardiopulmonary dysfunction. When administering antibiotics the high frequency of β‐lactamase‐producing strains must be taken into consideration.Pediatr Pulmonol 1989; 7:128‐132.
Loss of oxygen tolerance in newborn rabbits: Relationship to changes in eicosanoid and antioxidant levels
Authors: Holtzman Ronald B. , Adler Luba , Smith Lewis J. , Shamsuddin Mir , Hunt Carl E. , Hageman Joseph R. 
Published: March 2007

AbstractRelative tolerance of newborn animals to hyperoxia has been reported. This study investigated the age limitation of oxygen tolerance and mechanisms for its loss. Developmental changes in lungs of normoxic New Zealand rabbits were studied on days 1, 3, 4, 5, and 10 of life. These were contrasted with newborn and 7‐day‐old rabbits exposed to >95% O2 for 65 hours. Normoxic rabbits demonstrated a decrement in bronchoalveolar lavage (BAL) 6keto‐PGF1a, thromboxane B2, and lower lung catalase, total glutathione, and superoxide dismutase with maturation. Newborns were more tolerant to oxygen than 7‐day‐old rabbits. Oxygen exposure beginning on day 1 did not result in identifiable lung damage. Exposure beginning on day 7 resulted in microscopic evidence of injury and significant increases in BAL white cells, neutrophils and protein, and a trend toward higher BAL LTB4 compared to normoxic age‐matched controls. Antioxidants were higher in the hyperoxic 7 day‐olds, but remained lower than values in hyperoxic newborns. These results suggest that loss of oxygen tolerance in maturing rabbits is related to a developmental decrement in antioxidants and prostacyclin. Pediatr Pulmonol 1989; 7:200‐208.