bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Little 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

A 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

Passive 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

The 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

This 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

In 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

We 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

Airway 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

A 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

Periodic 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

The 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

Periodic 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

Branhamella 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

Relative 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.
Variability of pulmonary function tests in cystic fibrosis
Authors: Cooper Peter J. , Robertson Colin F. , Hudson Irene L. , Phelan Peter D.
Published: March 2007

The aim of this study was to define the within‐subject variability for tests of respiratory function in patients with cystic fibrosis (CF) within the day, from day to day and from week to week. Twenty‐eight patients with CF (aged 9–19 years) and 23 healthy height matched controls (aged 9–18 years) had measurements made of spirometry, lung volumes, maximal flows at three lung volumes and maximal inspiratory and expiratory pressures at the mouth. Testings were done on nine occasions, three times within a day, on consecutive days at one week intervals. Each individual's variability was summarized both as the within‐subject coefficient of variation (WCV) and within‐subject standard deviation (WSD). Means of WSD and median WCV are reported for both the patients with CF and normal subjects.

The within‐subject variability of VC, FEV1, TLC, RV, and RV/TLC was more appropriately assessed by the use of WSD rather than WCV. The WSDs in the CF group were significantly more variable (P <0.005) than in the normals for VC and FEV1. WCV best summarized within‐subject variation for FEF25–75, FRC, V̇25, V̇50max and V̇75max for which the CF subjects were significantly more variable (P <0.005). Individuals' variability was very consistent, therefore assessment of significant change could be made more accurately by predetermining the variability of that individual, rather than using group data.

We stress the importance to consider increased variability from day to day and week to week in the interpretation of change in lung function in patients with CF, and provide reference values for accurate interpretation of serial pulmonary function test results. Pediatr Pulmonol 1990; 8:16‐22.
Effects of dexamethasone on macrophages in fetal and neonatal rat lung
Authors: Lortie C. , King G. M. , Adamson I. Y. R.
Published: March 2007

The effects of injecting dexamethasone to pregnant and newborn rats on the subsequent production of macrophages in the lung and on their phagocytic activity and lysosomal enzyme content were evaluated from late gestation to postnatal day 10 using an organ culture system to collect macrophages. Pieces of lung tissue cultured 6 days on cover glasses produced a halo of macrophages adherent to the glass around the explants. Thymidine labeling showed that the macrophages were derived from dividing precursors in the pulmonary interstitium. DNA synthesis was reduced after steroid treatment, and fewer cells were obtained on cover glasses, particularly just after birth when the macrophage number usually increases. Phagocytic function was also diminished in cells collected after dexamethasone injection, particularly when derived from neonatal animals. In contrast, intracellular levels of non‐specific esterase and glucosaminidase were increased, probably indicative of lower phagolysosome formation and lower enzyme secretion. These results demonstrate that steroid administration to fetal or newborn animals subsequently reduces the number and phagocytic activity of macrophages in the lungs. This could reduce the defense mechanisms of the neonate and increase susceptibility to infection. Pediatr pulmonol 1990; 8:138‐144.
Total respiratory compliance in infants and young children with congenital heart disease
Authors: Davies C. J. , Cooper S. G. , Fletcher M. E. , Hatch D. J. , Helms P. J. , Gordon I. , Stocks J.
Published: March 2007

The multiple occlusion technique was used to measure total respiratory system compliance (Crs) in 62 infants and young children with congential heart disease (age range, 2 days to 2 years). Measurements were found to be reproducible in nine infants in whom repeat measurements were possible (maximum deviation between measurements < 10%). The incidence of failure to obtain accurate results was no greater than when studying infants without cardiopulmonary disease. However, in the presence of severe growth retardation or alinearity of volume‐pressure data, results may be difficult to interpret in individuals.

Results of Crs were related to non‐invasive assessments of cardiac disease severity using chest radiography and echocardiography. After the effects of growth had been taken into account, a significant negative relationship was found between Crs and the right pulmonary artery to aortic ratio, which reflects pulmonary vascular engorgement (P = 0.003, R2 = −0.40). However, no significant relationship was found between Crs and chest X‐ray score (P = 0.27). Pediatr Pulmonol 1990; 8:155‐161.
Pulmonary function and respiratory morbidity in school‐age children born prematurely and ventilated for neonatal respiratory insufficiency
Authors: Hakulinen A. L. , Heinonen K. , Länsimies E. , Kiekara O.
Published: March 2007

We examined 72 children aged 6–9 years to assess the effects of prematurity and ventilator treatment on subsequent lung function and respiratory morbidity. The preterm study group (n = 42) was divided into children with a history of bronchopulmonary dysplasia (BPD) (n = 10), children who had had neonatal respirator treatment but no BPD (n = 19), and children without severe neonatal respiratory problems (n = 13). The BPD children as a group had markedly lower specific airway conductance and larger residual volume than did the full‐term control group, but there were no significant differences in spirometric measurements. The BPD group also had higher respiratory morbidity requiring hospitalizations, particularly during the first 2 years of life, than did the children in the other study groups. Therefore, BPD may improve but does not disappear as age increases. Non‐BPD children who had had ventilator treatment as neonates recovered well and suffered no severe respiratory problems after infancy. Pulmonary function parameters in prematurely born children without neonatal ventilator treatment did not differ from those in the full‐term control group. Thus, neonatal lung disease seems to be a more important determinant of abnormal pulmonary function at a later age than is prematurity alone. Pediatr Pulmonol 1990; 8:226‐232.
Differential effects of pancuronium bromide on cardiopulmonary function in the neonatal lamb
Authors: Wolfson Marla R. , Shaffer Thomas H.
Published: March 2007

The effect of pancuronium bromide (Panc Br) on resting cardiopulmonary function and cardiopulmonary responses to intravenous injection of acetylcholine (Ach) and histamine (H) was evaluated in neonatal lambs. The animals were mechanically ventilated and managed to maintain physiologic gas exchange and acid‐base conditions. A proximal segment of the cervical trachea was bypassed; the developed pressure response of this segment (Pcervical trach) was used as a direct indication of airway smooth muscle contraction and bronchoconstriction. Pulmonary resistance (RP) and functional residual capacity were determined. The change in RP from resting values was used as a functional indicator of central and peripheral airway bronchoconstriction. Cardiovascular function and responses were evaluated from changes in mean arterial pressure and heart rate. Following Panc Br, there was a significant reduction in Ach‐induced Pcertical trach (−50 ± 9.2% SE) and RP (−46 ± 2.4% SE). In contrast, Panc Br did not significantly change Ach‐induced bradycardia and hypotension, cardiopulmonary responses to H, and resting cardiopulmonary function. The differential effects of Panc Br on cardiopulmonary function appear to be related to regional differences between cardiovascular and airway smooth muscle muscarinic receptors in the neonate. The results of this study elucidate a mechanism which may explain previously reported variability in the effect of Panc Br on neonatal cardiopulmonary function. Furthermore, the Panc Br‐related attenuation of airway smooth muscle responses suggests that this form of neuromuscular blockade affects the regulation of airway tone and may influence the susceptibility of the neonate to airway deformation consequent to mechanical ventilation. Pediatr Pulmonol 1990; 8:233‐239.
Investigation of cyanotic/apneic episodes and sleep‐related upper airway obstruction by long‐term non‐invasive bedside recordings
Authors: Abraham N. G. , Stebbens V. A. , Samuels M. P. , Southall D. P.
Published: March 2007

Over a 4 year period, investigations were performed on 226 infants and children suffering cyanotic episodes and 160 suspected to be the victims of sleep‐related upper airway obstruction. These investigations have been considerably aided by long‐term tape recordings of multiple cardiorespiratory and neurophysiological variables from non‐invasive sensors. In addition to identifying the underlying mechanisms responsible for cyanotic episodes, recordings have identified the presence or absence of airway obstruction, documented its severity by its effects on oxygenation and on sleep‐state organization, and evaluated objectively the effects of treatment. The recording system, which is transportable, has been especially developed for use outside of the specialized sleep laboratory and was used on patients in hospital wards and at home. Pediatr Pulmonol 1990; 8:259‐262.
Respiratory complications in children with spondyloepiphyseal dysplasia congenita
Authors: Harding Cary O. , Green Christopher G. , Perloff William H. , Pauli Richard M.
Published: March 2007

Mild respiratory distress at birth is a common occurrence in infants with spondyloepiphyseal dysplasia congenita (SEDC) while severe repiratory insufficency and death have been reported only rarely. We describe three infants with SEDC who experienced severe respiratory complications and required tracheostomies. Two of these infants have also needed long‐term continuous positive airway pressure to maintain adequate ventilation. The features and clinical course of these children are described, previous reports of respiratory complications in SEDC are summarized, mechanisms resulting in respiratory problems in SEDC are postulated, and comparison is made with mechanisms giving rise to respiratory risks in other skeletal dysplasias. Pediatr Pulmonol 1990; 9:49–54.
Accurate, noninvasive quantitation of expiratory gas leak from uncuffed infant endotracheal tubes
Authors: Knauth Alison , Baumgart Stephen
Published: March 2007

Accurate measurement of expiratory gas leak from uncuffed infant endotracheal tubes is an important requirement for evaluating the rates of metabolic gas exchange by indirect calorimetry in neonates receiving mechanical ventilation. The present study reports a new, noninvasive technique for the efficient collection and analysis of expiratory gases leaked from a closed‐circuit metabolic monitoring system recently described. A loose‐fitting face mask is placed over the infant's endotracheal appliance and air is entrained from the mask cavity at 100 mL/min for CO2 analysis by infrared capnometry. In vitro calibration of this apparatus demonstrates a relative error of less than 5% of simulated endotracheal tube leak. In vivo application to metabolic rate assessment (using the MGM Jr. metabolic cart) in 12 intubated, ventilated infants ranging from 1.56 to 4.07 kg study weight demonstrated endotracheal tube leaks from 0.49 to 7.40% of net CO2 production, which ranged 10.67 to 70.91 mL/min (or mean 8.22 ± 0.93 SEM mL/kg/min). The magnitude of tube leakage of mixed expiratory gases could not be predicted from endotracheal tube diameter, ventilator settings, or infant activity or posture. As new instrumentation becomes available to measure the rates of metabolic gas exchange in intubated infants, systematic evaluation of uncuffed endotracheal tube gas leaks becomes critical. Pediatr Pulmonol. 1990; 9:55–60.
Respiratory papillomas: Presentation before six months
Authors: Chipps Bradley E. , McClurg F. L. Don , Freidman Ellen M. , Adams George L.
Published: March 2007

The prognosis of respiratory papillomatosis (RP) in newborns appears to be less favorable than in infants and older children. In this series of four patients who developed symptoms of the disease within the first 6 months of life, the mortality was 100%. In these premature and term newborn infants, endoscopic laser surgery and medical and immunologic therapy were unable to control the growth of RP. Meticulous local removal of the airway lesions is the most reliable form of management. Pediatr Pulmonal 1990; 9:125–130.
A comparison of lung lamellar body phospholipids from premature and term infants: Is sphingomyelin a contaminant of surfactant?
Authors: Neumann M. A. , McMurchie E. J. , Gibson R. A.
Published: March 2007

Lamellar bodies were isolated from homogenates of lungs obtained at autopsy from premature infants (n = 9), and compared to lamellar bodies from three full term reference groups including 55 infants with sudden infant death syndrome (SIDS), 14 control infants, and 3 who succumbed to intra‐uterine death (IUD) at term. Analysis of the phospholipids was expected to reveal a high proportion of sphingomyelin (Spm) in the lamellar bodies isolated from the lungs of premature infants (24 to 33 weeks gestational age) since at this stage of their development the percentage of Spm in the amniotic fluid is high. However, Spm was either absent or a small proportion of the total phospholipid in lamellar body surfactant from these premature infants. Spm was also a small percentage of phospholipid in the lamellar body surfactant of infants with SIDS and from control and IUD specimens. It is suggested that Spm may not be a normal constituent of lamellar body surfactant but rather a contaminant from membranes. Pediatr Pulmonal 1990; 9:162–165.
Surfactant protein‐A in bronchoalveolar lavage fluid from neonates with RDS on conventional and high‐frequency oscillatory ventilation
Authors: Gerdes Jeffrey S. , Abbasi Soraya , Karp Karen , Hull William , Whitsett Jeffrey A.
Published: March 2007

Surfactant protein‐A (SP‐A) was measured in bronchoalveolar lavage (BAL) samples from ventilated neonates in order to study the concentration of SP‐A with regard to: 1) high‐frequency oscillatory ventilation (HFOV) vs. conventional mechanical ventilation (CMV); 2) the postnatal course and ontogeny of SP‐A; and 3) the correlation with measurements of pulmonary function. Patients on HFOV had markedly lower BAL SP‐A concentrations on days 1 and 2 compared to those on CMV, which may indicate influence of mode of ventilation on surfactant metabolism. The SP‐A concentrations increased postnatally concurrent with resolution of acute respiratory distress syndrome. Finally, there were only weak correlations between BAL SP‐A concentration and dynamic lung compliance and oxygen requirement. Pediatr Pulmonal 1990; 9:166–169.
Ventilation‐perfusion abnormalities in the preterm infant with hyaline membrane disease: A two‐compartment model of the neonatal lung
Authors: Hand Ivan L. , Shepard Eric K. , Krauss Alfred N. , Auld Peter A. M.
Published: March 2007

Arterial‐alveolar differences for oxygen, carbon dioxide, and nitrogen were measured in 7 non‐distressed preterm infants and 21 ventilator‐dependent preterm infants with hyaline membrane disease. The preterm infants with hyaline membrane disease had a significantly lower average arterial pH (7.34 vs. 7.44; P < 0.001), and significantly higher arterial‐alveolar differences for oxygen (286 mm Hg vs. 34 mm Hg; P < 0.005) and nitrogen (118 mm Hg vs. 7 mm Hg; P < 0.005). Both groups had elevated arterial‐alveolar differences for P (9 mm Hg in infants with hyaline membrane disease, 5 mm Hg in nondistressed infants; P < 0.2). When acute changes in mean airway pressure were produced in 14 distressed infants, arterial‐alveolar CO2 and N2 differences moved in opposite directions in 11 infants. This observation suggests that changes in mean airway pressure do not acutely recruit atelectatic alveoli, but cause redistribution of ventilation within alveoli already ventilated. Pediatr Pulmonal 1990; 9:206–213.
Effect of forced expiration on thoracic gas volume in wheezy infants
Authors: Lanteri Celia J. , Raven Joan M. , Sly Peter D.
Published: March 2007

Partial expiratory flow‐volume curves are commonly used in infant pulmonary function testing. The flow measurements are volume dependent and thoracic gas volume (TGV) is often measured in conjunction with forced expiratory maneuvers. Since it is not possible to make continuous, simultaneous measurements of TGV during forced expiration, it is assumed that lung volume returns to its original value after forced expiration. To test this assumption we measured TGV using a whole body plethysmograph in 14 wheezy infants before and after a series of forced expirations produced with an inflatable jacket. Forced expiration did not cause a significant change in group mean TGV measurements. Examination of individual data did not show any systematic difference between TGV measured before and after forced expiration. These results suggest that repeated forced expirations do not alter TGV within the time scale of usual pulmonary function testing protocols. Pediatr Pulmonal 1990; 9:220–223.
External intercostal muscle activity during acute hypoxia in the kitten
Authors: Guthrie Robert D. , Klesh Kenneth W. , O'Day Terrence L. , Watchko Jon F.
Published: March 2007

The effects of acute hypoxia on the recruitment of external intercostal muscle activity were determined in 12 kittens, aged 14 to 36 days. The animals were anesthetized with 1.23 ± 0.23% halothane and bipolar electrodes were placed in the costal and crural diaphragm and in dorsal external intercostal muscles. Acute hypoxia was induced by the animals breathing 13% oxygen; arterial gases were sampled during baseline conditions and at 1 and 5 min after induction of hypoxia. Peak‐moving average (PA) and minute electromyogram (EMG) activity (PA × f) were recorded during baseline conditions and at 1 and 5 min after onset of acute hypoxia. At 1 min of acute hypoxia, PA and PA × f of the costal diaphragm, crural diaphragm, and external intercostal muscles were significantly increased above baseline values (P < 0.01). After 5 min of acute hypoxia, PA of all three muscles remained elevated above baseline values (P < 0.05) but PA × f returned toward baseline levels. Respiratory frequency remained unchanged during the hypoxic stimulus. These data document that the newborn is capable of increasing inspiratory external intercostal muscle EMG activity during acute hypoxia. We speculate that this phasic recruitment could be of physiologic benefit to the newborn by stabilizing the compliant chest wall and by increasing the contribution of rib cage expansion to tidal breathing. Pediatr Pulmonal 1990; 9:233–237.
Digital clubbing and pulmonary function abnormalities in children with lung disease
Authors: Paton James Y. , Bautista Daisy B. , Stabile Michael W. , Waldman Amy E. , Nassar Annette G. , Platzker Arnold C. G. , Keens Thomas G.
Published: March 2007

Digital clubbing and pulmonary function tests were measured in children, adolescents, and adults with chronic lung diseases to determine pulmonary function correlates with a quantitative measure of clubbing. The group had a mean age of 13.8 ± 6.0 (SD) years, mean Pa of 81 ± 21 mm Hg, and mean FEV1 of 60% ± 26% predicted. Digital clubbing was diagnosed in 43 cases when the distal phalangeal depth to interphalangeal depth (DPD/IPD) ratio, measured on a finger cast, was ⩾1 (>3 SD above mean from 85 controls; no history of pulmonary disease; mean age, 14.8 ± 7.6). The Pa of patients with digital clubbing was 69.4 ± 2.1 (SEM) mm Hg compared with 88.3 ± 1.3 mm Hg in those without digital clubbing (P < 0.0001). Digital clubbing was present in 39 of the 84 (46%) hypoxic patients (Pa ⩽ 88) but only four of the 78 (5%) normoxic patients (P < 0.0001). The DPD/IPD ratio was negatively correlated with Pa in subjects with cystic fibrosis and interstitial fibrosis. Weak negative correlations were seen for all other subjects except asthmatics. Overall, the DPD/IPD ratio was significantly correlated with Pa (r = −0.53; P < 0.0001). The DPD/IPD ratio was correlated with other lung function abnormalities (increased RV, decreased FEV1, and FEF25%–75%) only for the subjects with cystic fibrosis. We conclude that digital clubbing is associated with hypoxemia and airway obstruction. The relation is seen most clearly in subjects with cystic fibrosis, possibly reflecting the prolonged duration of hypoxemia. Digital clubbing is rarely seen in normoxic subjects. Pediatr Pulmonol 1991; 10:25–29.
Circulating levels of tumor necrosis factor and interleukin‐1 in cystic fibrosis
Authors: Brown Mark A. , Morgan Wayne J. , Finley Paul R. , Scuderi Philip
Published: March 2007

To assess the role of tumor necrosis factor (TNF) and interleukin‐1 (IL‐1) in the pathophysiology of cystic fibrosis (CF)‐associated growth failure/cachexia and lung disease we measured height, weight, triceps skin fold, forced vital capacity, forced expiratory volume in 1 second, and plasma levels of TNF, interleukin‐1‐alpha (IL‐1α), interleukin‐1‐beta (IL‐1β), and alpha‐1‐antitrypsin (A1AT) in 12 patients with CF, and in 12 age‐ and gender‐matched healthy controls. The patients as a group had significantly lower values for the anthropomorphic measurements and lung function parameters as compared to controls. They also had higher circulating levels of A1AT than controls. TNF, however, was detected less frequently in patients than in controls. Neither group had detectable levels of circulating IL‐1α or IL‐1β, which is consistent with the observation that CF patients infrequently present with fever. Potential explanations for these findings include compartmentalization of secreted TNF/IL‐1, altered regulation of TNF/IL‐1 secretion as a result of the chronic inflammatory state seen in CF, or increased degradation of TNF/IL‐1, also a result of chronic inflammation. The role of these cytokines in the pathophysiology of CF remains unclear, but should be explored further; however it seems unlikely that circulating TNF plays a role in the growth failure/cachexia associated with CF. Pediatr Pulmonol 1991; 10:86–91.
Pulse oximetry versus measured arterial oxygen saturation: A comparison of the Nellcor N100 and the Biox III
Authors: Lebecque Patrick , Shango Polycarpe , Stijns Maddy , Vliers André , Coates Allan L.
Published: March 2007

Pulse oximetry is noninvasive, fast, and simple, making it a very popular way of assessing oxygenation in pediatric patients. However, there are few studies that establish the accuracy of this technology over a wide range of oxygen saturations in children. This study, done in 47 children aged from 1 day to 16 years with congenital heart disease and undergoing cardiac catheterization, compared the direct measurement of arterial oxygen saturation to values from pulse oximetry. Oxygen saturation was measured by an IL‐282 Co‐oximeter, which also measured carboxyhemoglobin and methemoglobin, and was compared to values obtained from both a Biox III and Nellcor N100. Both pulse oximeters gave values that closely correlated with the actual saturation (r = 0.91 and 0.93, respectively) with standard errors of the estimate of 4.1 and 3.2%, respectively. For both devices, the error increased with decreasing saturations, being progressively larger below a saturation of 80%. The difference between the actual saturation and that measured by pulse oximetry bore no relationship to the presence of carboxyhemoglobin, methemoglobin, fetal hemoglobin, bilirubin, cardiac index, or age of the patient. In conclusion, pulse oximetry, while a very useful technology in pediatrics, must be interpreted with some caution in children with severe cyanosis. Pediatr Pulmonol 1991; 10:132–135.
Aerosol delivery in neonatal ventilator circuits: A rabbit lung model
Authors: Cameron Duncan , Arnot Rosemary , Clay Michelle , Silverman Michael
Published: March 2007

The benefits of inhaled therapy in ventilated neonates are recognized, but the reliability of drug delivery in nebulizer‐ventilator circuits is uncertain. We quantified the effect of changing variables. Twenty‐three freshly killed rabbits (1.15–1.9 kg) were ventilated via a tracheostomy by a pressure‐limited, time‐cycled ventilator (Neovent). A radioaerosol of 99Tcm pertechnetate from an Ultravent nebulizer (Mallinkrodt) was fed into the proximal ventilator tubing. Two 3‐minute nebulizations at “standard settings” were followed by 2 at altered pressure, frequency, gas flow, I:E ratio, or position of the nebulizer in the circuit. Each nebulization was followed by a 3‐minute gamma camera image and total deposited radioactivity was measured in excised lungs and trachea. Images demonstrated good peripheral aerosol deposition. At standard settings, lung deposition averaged 2.8% of the aerosol released. This was decreased markedly by reducing tidal volume (ventilator pressures) and residence time of aerosol (I:E ratio). Reduced gas flow decreased deposition slightly, presumably by increased particle size and marginally reduced tidal volume. Deposition did not change with increased frequency; increased minute ventilation was offset by decreased residence time of the aerosol. We conclude that the Ultravent nebulizer can be used to nebulize drugs in a standard neonatal circuit, although the dose delivered is small. Tidal volume and aerosol residence time are important determinants of aerosol delivery. Pediatr Pulmonol 1991; 10:208–213.
Epidemiology of cystic fibrosis in latin america: Preliminary communication
Authors: Macri Carlos N. , de Gentile Angela S. , Manterola Alberto , Tomezzoli Silvana , Reis Francisco Caldeira , Garcia Isabel Largo , Fernandez José Luis Lezana
Published: March 2007

We conducted a retrospective study of 743 patients with cystic fibrosis (CF), covering the 1979–89 period in 4 Latin American (LA) institutions to evaluate the clinical features of the disease. The review, although dealing only with patients referred to, or diagnosed at these institutions may be considered to comprise the majority of patients living in these areas. Diagnosis was confirmed by the sweat test in all cases. There was a slight predominance of males, (61.0%) mainly in the Brazilian group. The mean age at diagnosis was over 3 years. This was similar to the mean age at admission. Almost half of the patients were still alive at follow‐up, but their mean age was low (6.4 years in Brazil, 7.4 in Chile, 9.6 in Mexico, and 11.3 in Argentina). Mean age at death ranged from 3.1 years (Chile) to 8.7 years (Argentina). The highest proportion of living patients was in Chile (71.4%) and the lowest in Argentina (33.8%). Survival curve comprised 15 years after diagnosis for the Argentinian group, compared to 6 years for the remaining groups. Fifty percent of the patients lived 6–7 years after diagnosis in Argentina, 4–5 years in Mexico and Chile, and 3 years in Brazil. Among Argentine patients 39.2% survived to 10 years of age, and 18% to 15 years. These findings suggest that CF is not rare in LA but extensive epidemiological studies are needed to obtain accurate figures on the magnitude of the problem. Pediatr Pulmonol 1991; 10:249–253.