bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of adenosine in the hypoxic ventilatory response of the newborn piglet
Authors: Lopes Jose‐Maria , Davis G. Michael , Mullahoo Krishna , Aranda Jacob V. 
Published: March 2007

AbstractThe role of intracerebral adenosine levels in the control of ventilatory response to hypoxia was explored in 15 spontaneously breathing intubated piglets, 1–5 days old, sedated with chloral hydrate. Respiration was recorded via by a pneumotachograph. In all animals exposed to hypoxia (12% 02) for 10 minutes. There was an initial increase in ventilation followed by a late decrease (the biphasic ventilatory response). Both intravenous caffeine citrate (20 mg/kg) and an Fiico of 0.05 separately abolished or attenuated the late ventilatory depression associated with hypoxia. In the same piglets, the administration of 10 pg dipyridamole, a competitive inhibitor of adenosine receptors, directly into the cerebral ventricles abolished the hyperventilatory response to hypoxia. Conversely, the use of 20 μg intraventricular 8‐phenyltheophylline abolished the late ventilatory depression associated with hypoxia. Neither drug had a direct effect on ventilation at the time of injection. These results suggest that adenosine is a part of the diphasic ventilatory response to hypoxia. Pediatr Pulmonol. 1994; 17:50–55. © 1994 Wiley‐Liss, Inc.
Validation of esophageal pressure occlusion test after paralysis
Authors: Lanteri Celia J. , Kano Sohei , Sly Peter D. 
Published: March 2007

AbstractMeasurements of respiratory mechanics are frequently made in ventilated infants and children. Esophageal pressure measurements (Pes using a balloon on a catheter have been used to partition the respiratory mechanics into lung and chest wall components. Appropriate positioning of this balloon is crucial to obtain accurate estimates of pleural pressure. Traditionally, in spontaneously breathing subjects the balloon position is assessed with an occlusion test. In ventilated subjects, it is not always possible to perform an occlusion test prior to paralysis, and even if such a test is performed it may not be relevant under conditions of positive pressure ventilation. We have assessed a positive pressure occlusion test that is suitable for paralyzed subjects. By occluding the airway opening and applying gentle pressure to the abdomen or rib cage, positive swings in pressure can be measured by both Pes and airway opening pressure (Pao). We compared traditional occlusion tests measured in 16 spontaneously breathing puppies to the positive pressure occlusion test performed after paralysis. In 2 pups we were unable to obtain a reasonable traditional occlusion test (>15% difference between Pes and Pao) but we obtained 10 traditional occlusion tests in each of the remaining 14 pups (2.1–14 kg). In 11 of these animals Ape, was within 10% of Pao. This compared well to positive pressure occlusion test using abdominal pressure performed after paralysis, where Apes was within 10% of ΔPao in 10 animals. In 9 of these pups occlusion tests were also performed by applying pressure on the rib cage, where ΔPes was within 10% of ΔPao in 6 animals. These results suggest that it is possible to perform accurate occlusion tests in paralyzed subjects by abdominal or rib cage compression with the airway occluded. Pediatr Pulmonol. 1994; 17:56–62. © 1994 Wiley‐Liss, Inc.
Improved oxygenation with exogenous surfactant administration in experimental meconium aspiration syndrome
Authors: Al‐Mateen K. Bakeer , Dailey Kimberly , Grimes Margaret M. , Gutcher Gary R. 
Published: March 2007

AbstractFifteen adult New Zealand white rabbits were used to determine if exogenous surfactant immediately improves oxygenation in experimental meconium aspiration syndrome (MAS). They were ventilated with 100% 02 before insufflating 3 mL/kg of 40% filtered meconium. Arterial blood gases, dynamic lung compliance (CLdyn) and resistance (RL) were monitored for 2 hours before and 1 hour after the intratracheal administration of calf lung surfactant extract or air placebo. The arteriallalveolar O2 tension ratio [P] increased 133% within 1 hour of surfactant therapy but CLdyn did not change. The increase of RL, was comparable in the surfactant and control groups after meconium instillation. A further increase of 44% in RL occurred after surfactant administration with no change in the controls. Qualitative histologic analysis confirmed the presence of alveolar meconium as well as inflammation and atelectasis. Persistently elevated RL suggested airway obstruction in both groups throughout the study. Most likely no increase in CLdyn occurred with surfactant administration or it could not be detected because it was measured only with ventilator‐induced breaths and ventilator settings were held constant. In the face of airway obstruction CLdyn is an inadequate reflection of pulmonary elasticity. We conclude that exogenous surfactant therapy improves oxygenation in this model of MAS. Further studies are needed to understand the mechanism of this improvement. Pediatr Pulmonol. 1994; 17:75–80. © 1994 Wiley‐Liss, Inc.
Bronchodilator responsiveness in infants with bronchiolitis
Authors: Tepper Robert S. , Rosenberg David , Eigen Howard , Reister Teresa 
Published: March 2007

AbstractWe evaluated 34 infants with bronchiolitis, (17 of both genders; mean age, 4.6 mos; ranges, 0.7–14.5 mos). The 20 inpatients were significantly younger than the 14 outpatients (2.6 vs. 8.2 months, P < 0.05), and more females were inpatients. Forced expiratory flows at functional residual capacity (VmaxFRC) were obtained at baseline, after aerosolized normal saline (NS), and metaproterenol (0.025 mL/kg in 2 mL NS). Flows were expressed as 2‐scores, the difference between the measured and predicted flows, divided by the standard deviation for the predicted value. At baseline, outpatients were more obstructed than inpatients (−1.64 vs. −0.95, P < 0.05), infants >2 months old were more obstructed than infants s2 months old (−1.54 vs. −0.80, P < 0.05), and males more than females (− 1.45 vs. −1.02, P < 0.05). Following NS the whole group had a small but significant decrease in 2‐scores (−1.23 to −1.31, P <: 0.05). Following metaproferenol, the younger infants had significantly (P < 0.05) higher Z‐scores compared to baseline and NS (−0.80 vs. −0.86 vs. −0.59). However, no significant changes occurred in older infants. Females also had an increased flow after metaproterenol and were less obstructed than after NS (−1.11 vs. −0.86, P < 0.015). In males no increased flows occurred after metaproterenol (− 1.45 vs. − 1.48). Bronchodilator responsiveness did not relate to severity of airway obstruction, history of family asthma, allergy, or passive smoke exposure. We conclude that inhaled metaproterenol improves airway function in a subgroup of infants with bronchiolitis, but the subgroup could not clearly be identified because age and gender were confounding factors. Pediatr Pulmonol. 1994; 17:81–85. © 1994 Wiley‐Liss, Inc.
Measuring clinical status in cystic fibrosis: Internal validity and reliability of a modified NIH score
Authors: Sockrider Marianna M. , Swank Paul R. , Seilheimer Dan K. , Schidlow Daniel V. 
Published: March 2007

AbstractWe examined measurement properties of the NIH Clinical Score for Cystic Fibrosis (CF) as an index of disease status. This score is being employed as a research tool for defining study populations and as an outcome measure, yet there are no published data on its reliability or how its items contribute to the overall measure of disease status. Criteria for scoring some items in the original index lack specificity. In this study, we used a modified score to have more clearly specified criteria, while retaining the original weightings and structure. For 200 patients with CF in two centers, we analyzed the total NIH Score and its subscores for internal consistency, interrater reliability, and factor analysis. Internal consistency indicates how inter‐related the items are. The pulmonary subscore and overall score had fairly high internal consistency. However, the general subscore had low internal consistency, suggesting that the items are not measuring a single element of disease status and should not be added. Factor analysis provides additional information on the underlying structure and relationships among items. Five factors (groups of items) were identified accounting for 85% of the consistent variance of 14 items. These factors were designated by items accounting for most of their variance: general pulmonary, weight, disability, psychosocial, and acute infiltrate. While inter‐rater reliability for the overall index was high, individual items showed less agreement. The results indicate that most of the variability in the NIH Score is attributable to pulmonary items in the first factor. The analyses suggest a new scoring structure for the NIH Score; the general subscore items do not contribute to the reliability or account for significant variance. Therefore, they will likely require further refinement or be eliminated. Pediatr Pulmonol. 1994; 17:86–96. © 1994 Wiley‐Liss, Inc.
High frequency jet ventilation: Intraoperative application in infants
Authors: Greenspan Jay S. , Davis Deborah A. , Russo Pierantonio , Antunes Michael J. , Spitzer Alan R. , Wolfson Marla R. 
Published: March 2007

AbstractThe potential advantages of the intraoperative use of high frequency jet ventilation (HFJV) when compared with conventional ventilation (CV) include the maintenance of adequate gas exchange and lung function with a relatively motionless surgical field. To determine the pulmonary response to HFJV ventilation in infants during cardiac surgery, we evaluated lung function in nine infants supported with CV and HFJV during a Blalock‐Taussig shunt procedure. Infants were randomized to each mode of ventilation with inspiratory and expiratory pressures and FiO2, held constant. Heart rate, blood pressure, arterial blood gases, pulmonary mechanics (lung compliance and resistance), and functional residual capacity (FRC) were compared after 10 minutes of stabilization of each ventilation mode, with the infants in the thoracotomy position and the surgical field adequately exposed. Pulmonary mechanics were measured using esophageal manometry and pneumotachography, and FRC by helium dilution. There was no difference in vital signs, pulmonary mechanics, FRC, or PaO2 on HFJV ventilation when compared with CV. Arterial P was lower with a lower mean airway pressure on HFJV when compared with CV. The surgical team subjectively observed a diminished need for lung manipulation and improved ease of access to the surgical field with HFJV. These results indicate that the use of HFJV during closed‐heart cardiac surgical procedures in infants provides similar cardiopulmonary stability and some potentially important clinical benefits when compared with CV. Pediatr Pulmonol. 1994; 17:155–160. © 1994 Wiley‐Liss, Inc.
Acute effects of ambient ozone on respiratory function of swiss schoolchildren after a 10–minute heavy exercise
Authors: Braun‐Fahrländer Ch. , Künzli N. , Domenighetti G. , Carell C. F. , Ackermann‐Liebrich U. 
Published: March 2007

AbstractThis study was conducted in Switzerland between May and October 1989 to assess possible decrements in lung function occurring as a result of 10 minute exposure to ambient air containing different ozone concentrations. Once a month, 128 children in two different areas of Southern Switzerland (Chiasso and Aurigeno) had a pulmonary function test before and after a standardized 10 minute exercise (pulse rate, 170imin) on a cycle ergometer, outdoors. Ozone concentrations were similar in both areas, ranging from 40 to 157 μg/m3 (112h means) during the exercise tests. The two communities differed with respect to long‐term average pollution levels. The mean NO2 concentration over the six months study period was 70 μg/m3 in Chiasso and 18 μg/m3 in rural Aurigeno.Of the eligible children 85% participated and attended 4–6 tests. Parents completed a standardized questionnaire on family background, home characteristics and the child's early and present illness history.A total of 500 acceptable pairs of spirograms and corresponding ozone concentrations (average 3.8 per child) were available for analysis. Regressions of each individual's pre‐post differences of FVC, FEV, and peak flow on ozone concentrations measured during the outdoor exercise indicated that elevated ozone levels significantly reduced peak flow values. Adjustments for temperature and relative humidity increased the magnitude of the peak flow slopes. The average adjusted regression coefficient for A‐peak flow on ozone was −2.28 mL/s/μg/m3 (95% Cl, −0.57 −3.99). It is noteworthy that the observed relationships occurred at ozone concentrations below 160 μg/m3 and after an exercise duration of only 10 minutes. Pediatr Pulmonol. 1994; 17:169–177. © 1994 Wiley‐Liss, Inc.
Disease severity and optimum mean airway pressure level on transfer to high frequency oscillation
Authors: Chan V. , Greenough A. , Giffin F. 
Published: March 2007

AbstractThe aim of this study was to assess whether the severity of the infant's lung disease determined the most appropriate change in mean airway pressure (MAP) level to use on transfer from conventional ventilation to high frequency oscillation (HFO). In addition, we wished to assess whether the oscillatory frequency employed affected gas exchange. Ten premature infants with respiratory distress syndrome (RDS) were studied at a mean postnatal age of 1.5 days. During HFO, the infants were studied at a MAP equivalent of that used during conventional ventilation (baseline MAP), then at 2 and 5 cmH2O above baseline at 10 Hz. At the MAP identified as optimum, that is, the one associated with the best oxygenation, the infants were then studied at 10, 15 and 20 Hz. Each oscillatory setting was maintained for 20 minutes after which time arterial blood gases were measured. Prior to transfer to the oscillator, the peak inspiratory pressure was recorded, the P calculated and compliance of the respiratory system Crs) measured. In nine infants, the optimum baseline MAP was +5 cmH2O. Oxygenation at that level was better than on conventional ventilation (P < 0.05), but there was no significant change in CO2 elimination. The optimum MAP was related to the peak pressure during conventional ventilation (P < 0.01) and inversely related to Crs (P < 0.01). There was no significant relationship with the P. At the optimum MAP, the only significant effect of frequency was an impairment of oxygenation at 20 Hz. We conclude that if a volume optimization strategy is pursued among infants with stiff lungs due to RDS, the appropriate starting level of MAP can be identified by stepwise changes in MAP. Impairment of oscillator performance at high frequencies can affect gas exchange. Pediatr Pulmonol. 1994; 17:178–182. © 1994 Wiley‐Liss, Inc.
Influence of duration mechanics measured of occlusion time on respiratory with the single‐breath technique in infants
Authors: Mallol Javier , Willet Karen , Burton Paul , Sly Peter D. 
Published: March 2007

AbstractTo determine the effect of the length of end‐inspiratory occlusion on the values of respiratory system compliance (Crs and resistance (Rrs) calculated from the single‐breath technique, 6 infants with cystic fibrosis were studied. End‐inspiratory occlusions lasted between 0.3 and 1.2 seconds, and between 8 and 32 separate occlusions were made in each infant. Examination of the individual data showed a systematic tendency for C, to decrease as the length of the airway occlusion increased, with statistical significance reached in two subjects. Using a random effects model, it was demonstrated that there was a decrease of 0.1 5 Ml/cmH2O in Crs for each 0.1 s increase in occlusion time. The influence of length of plateau time for C, was similar to that of total occlusion time. No such tendency was seen for Rrs. These data reinforce the current emphasis on greater standardization in the methodologies used for infant lung function testing and for more fully reporting methodological details. Pediatr Pulmonol. 1994; 17:250–257. © 1994 Wiley‐Liss, Inc.
Effective pulmonary blood flow in children with acute asthma attack requiring hospitalization
Authors: Yiallouros Panayiotis K. , Milner Anthony D. 
Published: March 2007

AbstractIn children with acute obstructive lung disease gas exchange is affected by ventilation‐perfusion mismatch and the degree of bronchoconstriction. Standard lung function measurements do not reflect the impairment in gas exchange. Alternatively, the effective pulmonary blood flow (EPBF), that is, the proportion of the cardiac output that is supplying well‐ventilated lung units, can give accurate and noninvasive estimates of ventilation‐perfusion mismatch. We measured EPBF with the argon freon −22 rebreathing technique in children with acute severe asthma to assess their response to nebulized salbutamol and to determine whether induced changes in the EPBF could be predicted from baseline measurements. Twenty‐four children admitted with an acute asthma attack had spirometry and triplicate EPBF measurements before and after nebulized salbutamol. Eighteen patients had repeated tests 50 days later when fully recovered; 4 patients were taking methylxanthines on at least one occasion. The mean forced expiratory volume in 1 sec (FEV1) rose from 55% of predicted to 66% after salbutamol and to 83% with recovery. The mean coefficients of variation for EPBF measurements on the three test occasions were 11.3%, 8.2%, and 9%. Except in children on methylxanthines, the EPBF values were reduced during the acute asthma attack (median, 2.53 L/min/m2; range, 1.99–3.60 L/min/m2) compared with paired values obtained after recovery (median, 2.89 L/min/m2; range, 2.2Eb4.04 L/min/m2) (P = 0.009). Salbutamol caused a highly significant increase in EPBF from 2.88 L/min/m2 (range, 1.86–3.80) before treatment to 3.34 L/min/m2 (range, 2.264.65) immediately afterwards (P = 0.0003). The spirometric indices did not relate to the changes in the EPBF values. However, when the effective stroke volume index was calculated in 11 patients, the changes induced by nebulized salbutamol had a significant inverse relation with the pretreatment FEV, (P = 0.61; P = 0.02). In conclusion, the argon freon‐22 rebreathing technique can be used successfully and reproducibly to measure EPBF in children with an acute asthma attack. Except in children taking methylxanthines, EPBF during the acute attack is reduced and rises significantly after salbutamol. EPBF values after recovery were significantly higher than the presalbutamol values during the attack. Spirometric indices do not relate to the EPBF changes but are inversely related to the effective stroke volume changes. Pediatr Pulmonol. 1994; 17:370–377. © 1994 Wiley‐Liss, Inc.
β2‐Agonists and running economy in prepubertal boys
Authors: Unnithan Viswanath B. , Thomson Kevin J. , Aitchison Thomas C. , Paton James Y. 
Published: March 2007

AbstractAsthmatic athletes (adults and junior) have competed successfully at the highest level for many years assisted by pre‐event medication with β2‐agonists. To examine the impact of (β2–agonists upon submaximal running economy (oxygen consumption at a given submaximal work load), we studied 10 nonasthmatic boys (age, 10.4 ± 0.48 years, mean ± SD). They each completed submaximal (speeds, 7.2, 8.0, and 8.8 km/hr) and peak treadmill running protocols preceded by treatment with β2‐agonist (terbutaline, 500 (μg via nebuhaler) or placebo in a randomized, crossover single‐blind study. No significant differences were found between running economy and heart rate during the submaximal exercise tests or between peak oxygen consumption (V02), peak respiratory exchange ratio, peak heart rate (HR), or total running time during the peak V02 test. Pretreatment with terbutaline did produce small but nonsignificant increases in aerobic fractional utilization (percent peak V02 on drug: 65.9%, 72.6%, and 76.7% vs. placebo: 65.1%, 70%, and 75.5%), at the three submaximal work loads. Respiratory exchange ratio (RER) values were elevated throughout the submaximal tests (on drug: 0.94, 0.93, and 0.94 vs. placebo: 0.91, 0.92, and 0.91, P < 0.05). No significant differences were found between drug and placebo for minute ventilation (VE) and ventilatory equivalent for oxygen (VE/V02), at both submaximal and peak exercise intensities. The significant increase in forced expiratory volume in 1 second (FEV1) (% predicted) found following submaximal (pre: 107 ± 13 vs. post: 111 ± 17, P < 0.001) and peak exercise (pre: 103 ± 10 vs. post: 106 ± 14, P < 0.001), both with drug and placebo, suggests an effect of exercise rather than of drug. These results indicate that therapeutic doses of an inhaled β2–agonist administered immediately pre‐exercise do not enhance the submaximal running economy or peak V02 of nonasthmatic children.
Bronchopulmonary infection with Moraxella catarrhalis in infants requiring extracorporeal membrane oxygenation
Authors: Fenton Alan C. , Foweraker Juliet E. , Pearson Gale A. , Firmin Richard K. 
Published: March 2007

AbstractMoraxella (formerly Branhamella) catarrhalis is now a well‐recognized pathogen of the upper and lower respiratory tract. Four pediatric cases of life‐threatening pneumonia requiring extracorporeal membrane oxygenation are presented. M. catarrhalis was isolated within 48 hours of admission in three of the cases and within 24 hours of an acute deterioration in the fourth. We conclude that M. catarrhalis is either a significant pathogen in its own right, a marker of severe disease, or a secondary invader. Pediatr Pulmonol. 1994; 17:393–395. © 1994 Wiley‐Liss, Inc.
Prenatal cocaine exposure alters postnatal hypoxic arousal responses and hypercarbic ventilatory responses but not pneumocardiograms in prenatally cocaine‐exposed term infants
Authors: Gingras Jeannine L. , Muelenaer Andre , Dalley Linda B. , O'Donnell Karen J. 
Published: March 2007

AbstractTo test the hypothesis that respiratory control is altered in cocaine‐exposed infants, we evaluated the hypoxic arousal response and the ventilatory response to carbon dioxide (CO2) in 18 term newborn infants prenatally exposed to cocaine and in 10 healthy, term newborn infants within the first week of life. Three infants could not be tested for the hypoxic arousal response because of low baseline oxygen saturation, and data from these infants were excluded from analysis. Twelve hour overnight pneumocardiograms were performed on all infants. Results show that 60% (9/5) of the prenatally cocaine‐exposed infants had an abnormal hypoxic arousal response and 87% (13/15) had abnormal hypercarbic ventilatory response. Only 6% (1/15) of the prenatally cocaine‐exposed infants demonstrated any abnormality on pneumocardiogram. In contrast, all control infants (10/10) were aroused by the hypoxic challenge and 80% (8/10) had normal ventilatory response to CO2. No abnormalities were found in the assessment of the overnight pneumocardiogram in the control infants. For the cocaine‐exposed infants, test abnormalities were not correlated with a concurrent positive urine toxicology for cocaine, suggesting that the injury occurs early in development. These findings support the hypothesis that infants prenatally exposed to cocaine demonstrate abnormalities of respiratory control.Pediatr Pulmonol. 1994; 18:13–20 © 1994 Wiley‐Liss. Inc.