bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiologic effects of terbutaline on pulmonary function of infants with bronchopulmonary dysplasia
Authors: Sosulski Richard , Abbasi Soraya , Bhutani Vinod K. , Fox William W.
Published: March 2007

This study defines the physiologic changes in pulmonary mechanics induced by subcutaneous terbutaline administration in ventilator‐dependent infants with severe bronchopulmonary dysplasia (BPD). Eight such infants (mean ± SEM weight = 2.56 ± 0.32kg, postnatal age = 13.0 ± 3.2 weeks) were chosen for the study. Pulmonary mechanics and arterial blood gases were measured in the control state and at 30 and 60 minutes following the subcutaneous injection of 5 μg/kg terbutaline. There was a significant (p < 0.001) improvement in lung compliance from baseline values at 30 minutes and at 60 minutes (38%). A significant (p < 0.05) decrease of 23% in the average pulmonary resistance at 30 minutes and a 26% decrease at 60 minutes from control values were observed. An increase in the I/E ratio occurred in all patients at 60 minutes (p < 0.01). In addition, clinical improvement was noted in six of eight infants. Administration of terbutaline demonstrated a significant improvement in the pulmonary mechanics of infants with severe BPD.
Multiple factors limit exercise capacity in cystic fibrosis
Authors: Marcotte Jacques E. , Grisdale Robert K. , Levison Henry , Canny Gerard J. , Coates Allan L.
Published: March 2007

Exercise testing was performed in 50 patients with cystic fibrosis to determine whether hemodynamic factors limit exercise capacity in the disease. Prior to exercise testing, lung function and blood gas values were measured. Nutritional status was determined by calculating a weight for height (Wt for Ht) ratio for each subject. A progressive exercise test was used to determine maximum work capacity (Wmax). Cardiac output (Q) (indirect Fick method), and stroke volume (SV) were computed during steady‐state exercise at 50% Wmax in 21 of 50 patients. Wmax, SV, Q, and lung function results are expressed as per cent predicted. The mean (± SD) Wmax was 75 ± 23%. Multiple regression analysis showed that maximum voluntary ventilation, resting Pao2, and Wt for Ht accounted for 84% of the variance in Wmax. Although some patients had a reduced SV (mean = 96%) during steady‐state exercise, all patients achieved a normal cardiac output (mean = 115%). SV correlated with resting Pao, but not with lung function. We conclude that (1) exercise capacity in cystic fibrosis is influenced by lung function, nutritional status, and resting hypoxemia, but not by cardiac function; (2) the SV limitation noted in some patients may be due to increased pulmonary vascular resistance related to hypoxemia.
Single‐dose pharmacokinetics of aztreonam in children with cystic fibrosis
Authors: Reed Michael D. , Aronoff Stephen C. , Stern Robert C. , Yamashita Toyoko S. , Myers Carolyn M. , Friedhoff Lawrence T. , Blumer Jeffrey L.
Published: March 2007

The single‐dose pharmacokinetics of aztreonam was evaluated in 10 clinically stable subjects with cystic fibrosis. Each child received 30 mg aztreonam/kg intravenously over 2 to 3 minutes. Multiple timed blood samples were obtained over 8 hours for determination of aztreonam elimination kinetics; all urine excreted for 24 hours was collected in timed aliquots for the determination of aztreonam and its microbiologically inactive metabolite, SQ 26,992. Aztreonam pharmacokinetic parameters were determined by model‐independent methods. Mean t1/2, steady‐state volume distribution, and body clearance were 1.3 hr, 0.25 L/kg, and 127.2 ml/min/1.73m2, respectively. In 9 of the 10 subjects, two‐compartment pharmacokinetic analysis was possible and compared favorably with model‐independent parameter estimates. Twenty‐four‐hour urinary recovery of aztreonam was 76.3% of the administered dose; 2.6% was recovered as the metabolite SQ 26,992. The renal clearance of aztreonam averaged 92.5 ml/min/1.73m2. When these data are combined with in vitro susceptibility data for aztreonam against Pseudomonas aerusinosa isolated from the sputum of patients with cystic fibrosis, a dose of 200 mg aztreonam/kg/day divided six hourly would be predicted to maintain serum concentrations above the minimum inhibitory concentration (MIC) for these organisms for the majority of the dosing interval.
Comparison of the lung sound frequency spectra of infants and adults
Authors: Kanga Jamshed F. , Kraman Steve S.
Published: March 2007

Auscultation of the infant chest reveals lung sounds that seem different from those of adults. To characterize this subjective difference, we compared the phonopneumographic median frequencies of lung sounds of seven full‐term and six premature infants with those of seven adults free of cardiopulmonary disease. The median frequencies over the upper lobes for the adults, term infants, and premature infants were 282 ± 63(SD) Hz, 383 ± 80 Hz, and 483 ± 86 Hz, respectively. At this location the differences among the three groups were significant (p < 0.01), Over the lower lobes, the median frequencies for the adults, term infants, and premature infants were 243 ± 56 Hz, 386 ± 76 Hz, and 390 ± 63 Hz, respectively. Here the difference between the adults and both groups of infants was significant (p < 0.01), but that between the term and premature infants was not. We conclude that the normal lung sounds of newborn infants contain higher frequency components than those of adults. We postulate that this difference is the result of less filtering of the lung sound in infants. This difference should be considered when lung sounds of infants are described or assessed for the presence of abnormalities.
A comparison of pneumogram recordings in infants in the hospital and at home
Authors: Keens Thomas G. , Davidson Ward Sally L. , Gates Eileen P. , Hart Lynnie D. , Basile Anna , Tinajero Lydia A. , Lau Albert M. , Chan Caroline E.
Published: March 2007

It is not known how environment affects the ventilatory pattern of infants during sleep. Pneumogram recordings of ventilatory pattern and electrocardiograms are performed both in the hospital and at home. However, it is not known if the data obtained in these two settings are comparable. Therefore, 12‐hour overnight PNGs were recorded in the hospital and at home within 10 days on 64 infants in three diagnostic categories: apnea of infancy, apnea of prematurity, and siblings of victims of sudden infant death syndrome. Pneumograms were quantitated for total sleep time (TST in minutes), longest apnea (in seconds), periodic breathing, and the total duration of apneas lasting 6 seconds or longer. TST was longer at home for the total group (p < 0.001) and for the apnea of infancy group (p < 0.005). No other differences were found between hospital and home recordings for any parameter. There was no difference in the number of abnormal pneumograms recorded in the hospital and at home. Therefore, hospital and home pneumogram recordings are equally sensitive and accurate.
Ventilatory response to inspired carbon dioxide in premature infants recovering from intraventricular hemorrhage
Authors: Anwar Mujahid , Fort Maria , Marotta Fran , Mondestin Harry , Hiatt I. Mark , Hegyi Thomas
Published: March 2007

We examined the ventilatory response to inhaled carbon dioxide with a computerized waveform analyzer in two groups of premature infants. Twenty‐seven infants suffered from periventricular‐intraventricular hemorrhage (IVH) during the first week of life and comprised the study group (birth weight 1.2 ± 0.2 kg, gestational age 29 ± 2 weeks). The control group consisted of 15 infants without IVH (birth weight 1.4 ± 0.3 kg, gestational age 30 ± 2 weeks). Study infants were evaluated at a postnatal age of 9 ± 2 weeks and control infants at 7 ± 3 weeks. No differences were found in the slope or position of the ventilatory response curve, baseline PACO2, increase in minute ventilation, VT/Ttot, and Ti/Ttot between the two groups. Subgroups with unresolved apnea (10 IVH and eight control infants) demonstrated a rightward shift of the ventilatory response curve compared to those infants without apnea. A previous IVH did not reduce the ventilatory response to CO2 in this group of infants. Pediatr Pulmonol 1987; 3:13–18.
Human fetal lung changes associated with maternal smoking during pregnancy
Authors: Chen M. F. , Kimizuka G. , Wang N. S.
Published: March 2007

Pulmonary impairment in the offspring of smoking mothers is well documented by epidemiologic studies. The morphologic bases for the functional impairment are largely unexplored. We studied 17 infant lungs obtained at autopsy, ten from smoking (group 1) and seven from nonsmoking (group 2) mothers, by light (LM), transmission (TEM), and scanning electron microscopy (SEM). By LM, the alveolar mean linear intercept was similar in both groups; the total lung volume and alveolar surface area increased with the increase in gestational age in all lungs studied. By SEM, the sizes of the neuroepithelial bodies (NEB) were larger in group 1 than in group 2. By SEM and TEM, ciliated cells were increased, but the amount of dense core granules was decreased, in the NEB of the smoking group. Maternal smoking during pregnancy appears to alter the size and cellular composition of fetal NEB. The detailed mechanisms of the alteration in NEB and their implications are unclear from this study and need further clarification. Pediatr Pulmonol 1987; 3:51–85.
Improved accuracy of the occlusion technique for assessing total respiratory compliance in infants
Authors: Stocks Janet , Nöthen Ursula , Sutherland Pat , Hatch David , Helms Peter
Published: March 2007

The occlusion technique to measure total respiratory system compliance (Cocc) was used in 28 sedated infants with a variety of cardiopulmonary diseases and 14 anaesthetised infants during the first 2 years of life. In this report, we describe some of the potential problems in the technique and how to avoid them. Invalidation of the occlusion technique because of consistent failure to relax during brief airway occlusions occurred in only four of 42 infants despite the fact that only four infants were studied during the first month of life and 17 were between 12 and 26 months old. The technique was invalidated in two intubated infants because of persistent leaks around the endotracheal tube. In the remaining 36 infants, data sometimes had to be excluded as a result of instability of end‐expiratory volume, intermittent leaks, or failure to relax during occlusions performed at low lung volumes or during inspiration. However, by performing 15–25 occlusions per infant, it was possible to obtain sufficient reliable data for accurate analysis of Cocc in all these infants. Providing that the potential errors and limitations of the occlusion technique are recognized, it appears to be applicable to a wide range of healthy and sick infants. Pediatr Pulmonol 1987; 3:71–77.
Use of caffeine in infants unresponsive to theophylline in apnea of prematurity
Authors: Davis J. M. , Spitzer A. R. , Stefano J. L. , Bhutani V. , Fox W. W.
Published: March 2007

Eleven premature infants with severe apnea unresponsive to therapeutic the ophylline levels were studied to determine if caffeine is an effective treatment in such cases. Apnea was documented and quantitated with thermistor‐pneumocardiograms measuring heartrate, thoracic impedance, and nasal air flow. Infants with prolonged central or mixed apnea were then treated with caffeine and restudied. Caffeine reduced the total number of apneic episodes of > 10 sec duration by 80% (P < 0.01) and prolonged episodes of apnea (> 20 sec) by 88% (P < 0.05). These data suggest that caffeine may be effective in the management of apnea of prematurity, particularly the prolonged type, unresponsive to theophylline. Pediatr Pulmonol 1987; 3:90–93.
Gastroesophageal reflux and unexplained chronic respiratory disease in infants and children
Authors: Malfroot A. , Vandenplas Y. , Verlinden M. , Piepsz A. , Dab I.
Published: March 2007

Thirty‐eight children, aged from a few weeks to 7 years, with severe chronic pulmonary disease and without gastrointestinal symptoms, were investigated for gastroesophageal reflux (GER), using prolonged pH probe monitoring and gastroesophageal scintiscanning. All treatments were discontinued before testing. GER was found in 24 patients (63%) (group 1) and it was not observed in 14 patients (group II). All patients of group I received antireflux treatment, consisting of cisapride; in 22 of 24 patients, GER was controlled, as indicated by improvement of either pH monitoring or scintiscanning, or both. Eighteen of these 22 (82%) had remission of their pulmonary disease, and only two patients of group II (14%) had spontaneous remission of the respiratory symptoms. We concluded that GER was probably the cause of the respiratory disease in 63% of our patients, since treatment of GER was followed by disappearance of the respiratory complaints in most of them. The combination of gastroesophageal scintiscanning and pH probe study improved the diagnostic accuracy.
Pulmonary function following varicella‐zoster pneumonia in children with leukemia
Authors: Stokes Dennis C. , Feldman Sandor , Sanyal Shyamal K. , Mackert Paul W.
Published: March 2007

Varicella‐zoster virus (VZV) is a cause of serious pneumonias in immunosuppressed patients. Although there are reports of residual lung changes in adults following VZV pneumonia, no previous studies of lung function in children following this infection have been done. We studied 11 patients (median age 11 years) who had had VZV pneumonia 1 to 16 years previously. All patients had a primary diagnosis of acute lymphocytic leukemia. Pneumonia was mild in most of the patients: Three had only radiographic evidence of pneumonia and required no supplemental oxygen, and seven required an Fio2 ≤ 0.4 for intervals for up to 11 days. One patient had severe pneumonia and required major ventilatory support. Three patients (27%) had significant restrictive defects on follow‐up, with total lung capacity 62–69% predicted; and a fourth was abnormal at 1 month follow‐up but normal at 16 months. No obstructive defects were noted, although RV/TLC ratios were elevated in three patients and volume of isoflow increased in three. Single breath diffusing capacity was reduced in two patients, but gas exchange was normal in all. No residual radiographic changes were present except in the patient who had severe pneumonia and increased lung markings at 2 months follow‐up. All three patients with restrictive changes had other infections before or following VZV, including Pneumocystis carinil pneumonia in two and recurrent, nonspecific pneumonias in the third. We conclude that VZV pneumonia had minimal residual effects on lung function in children with leukemia.
Use of nebulized bronchodilators in infants under 1 year of age: Analysis of four forms of therapy
Authors: Mallol Javier , Barrueto Luis , Girardi Guido , Muñoz Ricardo , Puppo Homero , Ulloa Victor , Toro Olivia , Quevedo Fernando
Published: March 2007

The main purpose of this study was to evaluate four different forms of treatment in young infants admitted for acute wheezing (AW). Seventy‐nine infants less than one year of age were randomly assigned to one of five groups. Group 1 received nebulized fenoterol plus ipratropium bromide, group 2 fenoterol, group 3 fenoterol plus steroids, and group 4 aminophylline, IV, plus steroids and oral fenoterol; the control group, or group 5, received nebulized normal saline solution. Clinical evaluation was done by means of a scoring system. The effectiveness of treatments was estimated by a score decrease in the first 24 hours, by the percentage of patients whose scores did not decrease during the same period, and by the number of days in the hospital.

All infants had significantly decreased scores, except those in the control group; the aminophylline group included a greater percentage of patients who did not abate their scores, and they stayed in the hospital for more days than those in the other groups. The fenoterol group had the shortest hospital stay.

All four treatments produced objective clinical improvement in bronchial obstruction. However, the nebulized bronchodilator treatments were more effective than aminophylline IV in decreasing scores on the first day, and they resulted in shorter hospitalization. Pediatr Pulmonol 1987; 3:298–303.
Bronchodilator effect of fenoterol and ipratropium bromide in infants with acute wheezing: Use of MDI with a spacer device
Authors: Mallol Javier , Barrueto Luis , Girardi Guido , Toro Olivia
Published: March 2007

Twenty‐eight infants admitted to Exequiel Gonzalez Cortes Children's Hospital because of acute wheezing (AW) were randomly assigned to three study groups. Fenoterol (FNT), ipratropium bromide (IB), and placebo were administered respectively to children in the different groups by means of metered dose inhalers (MDI) with spacers, using doses of 3 puffs every hour, for 4 hours. The degree of bronchial obstruction was assessed clinically and scored with the single‐blind method every hour prior to each treatment. The criterion of a bronchodilator effect was a significant decrease in the degree of bronchial obstruction at subsequent scorings. The scores of the three groups were compared using the Student's t test for matched samples. The same test was also applied to the independent samples for determining the superiority of one treatment, FNT or IB, over the other.

The results indicated a significant decrease in the scores of the groups receiving FNT and IB (P < 0.05); this did not occur in the group in which placebo was used. FNT produced a more rapid and sustained effect than IB (P < 0.05). Significant bronchodilator effect was obtained in infants with AW when repeated doses of FNT or IB were administered with MDI and spacers. This effect was significantly greater in the group treated with FNT. Pediatr Pulmonol 1987; 3:352–356.
Stridor and gastroesophageal reflux: Diagnostic use of intraluminal esophageal acid perfusion (Bernstein Test)
Authors: Orenstein Susan R. , Kocoshis Samuel A. , Orenstein David M. , Proujansky Roy
Published: March 2007

Five pediatric patients with stridor were evaluated to determine whether gastroesophageal reflux (GER) contributed to their stridor. Intraluminal esophageal acid perfusion (Bernstein test), pH probe, radiographic studies, laryngobronchoscopy, and esophageal histology were utilized. Thereafter, three of the five patients responded to therapy for GER; two did not. The Bernstein test proved to have greater diagnostic reliability than any other test employed, using response to antireflux therapy as the “gold standard” for diagnosing reflux‐provoked stridor.
Determination of airway hyper‐reactivity in asthmatic children: A comparison among exercise, nebulized water, and histamine challenge
Authors: Fourie Pieter R. , Joubert James R.
Published: March 2007

An easy and accurate method of assessing bronchial hyper‐reactivity could be of great value in identifying and classifying the degree of severity of asthma in children. The sensitivity and specificity of three methods of provocation, ie, histamine, nebulized water, and exercise, were compared in 20 asthmatic and 20 control children between ages 5 and 13 years. Three clinical categories of severity ranging from slight (Group 1) through moderate (Group 2) to severe asthma (Group 3) were identified. The three methods were compared in each subgroup for detecting a tendency to bronchospasm. An inverse correlation (— 0.57) was found between the histamine dose and clinical degree of severity, whereas distilled water and exercise proved to be too insensitive for identifying Group 1 asthmatics. Histamine challenge in children is a safe and sensitive technique for identifying asthma and for monitoring the severity of the disease during follow‐up.
Ventricular dysfunction in children with obstructive sleep apnea: Radionuclide assessment
Authors: Tal Asher , Leiberman Alberto , Margulis Giora , Sofer Shaul
Published: March 2007

Ventricular function was evaluated using radionuclide ventriculography in 27 children with oropharyngeal obstruction and clinical features of obstructive sleep apnea. Their mean age was 3.5 years (9 months to 7.5 years). Conventional clinical assessment did not detect cardiac involvement in 25 of 27 children; however, reduced right ventricular ejection fraction (less than 35%) was found in 10 (37%) patients (mean: 19.5 ± 2.3% SE, range: 8–28%). In 18 patients wall motion abnormality was detected. In 11 children in whom radionuclide ventriculography was performed before and after adenotonsillectomy, right ventricular ejection fraction rose from 24.4 ± 3.4% to 46.7 ± 3.4% (P < 0.005), and in all cases wall motion showed a definite improvement. In five children, left ventricular ejection fraction rose > 10% after removal of oropharyngeal obstruction. It is concluded that right ventricular function may be compromised in children with obstructive sleep apnea secondary to adenotonsillar hypertrophy, even before clinical signs of cardiac involvement are present.
Alveolar brush cells in an infant with desquamative interstitial pneumonitis
Authors: Dimaio Mary F. , Dische Renate , Gordon Ronald E. , Kattan Meyer
Published: March 2007

A full‐term infant developed bilateral pneumothoraces and respiratory distress shortly after birth, despite initially good Apgar scores. Persistent tachypnea, hypoxemia, and a chest X‐ray remarkable for diffuse alveolar and interstitial infiltrates prompted a lung biopsy at 4 months of age. The biopsy revealed desquamative interstitial pneumonitis with the unique demonstration by electron microscopy of numerous alveolar brush cells. Respiratory brush cells occur normally in the trachea and bronchi of humans and mammals. Although identical cells have been noted in the alveoli of rats, they have never been reported in the alveoli of humans. We present the first electron microscopical demonstration of the alveolar brush cell in humans.
Comparison of the protective effect and duration of action of orally administered clenbuterol and salbutamol on exercise‐induced asthma in children
Authors: Boner A. L. , Vallone G. , Brighenti C. , Schiassi M. , Miglioranzi P. , Richelli C.
Published: March 2007

Clenbuterol (C), a long‐acting β2‐selective bronchodilator was compared with salbutamol (S) in exercise‐induced asthma (EIA) at two premedication time levels. Sixteen asthmatic children with EIA living at an altitude of 1,750 m were treated with C (0.001 mg/kg) and S (0.12 mg/kg), administered randomly in a doubleblind cross‐over study 90 and 300 minutes before exercise tests of running on a treadmill for 6 minutes. Pulmonary functions were evaluted prior to the administration of the drugs and immediately before, at the end of, and 2, 5, 10, 15, 20, and 25 minutes after exercise tests. In the preliminary screening exercise test the mean fall of FEV1 was 41.1%, but it was 21.0% and 27.1% after S and 21.9% and 19.9% after C administered 90 and 300 min prior to the test, respectively. Salbutamol administered 300 minutes before the test was statistically less effective than the same drug administered 90 minutes before the test or C administered 300 minutes before the test. Therefore, we can conclude that clenbuterol provides a more lasting protection than salbutamol in EIA. Pediatr Pulmonol 1988; 4:197–200.
Computer analysis of physical factors affecting the use of the interrupter technique in infants
Authors: Sly Peter D. , Bates Jason H. T.
Published: March 2007

The interrupter technique involves measuring pressure changes at the airway opening following abrupt interruption of airflow, and relies on rapid equilibration of alveolar and airway opening pressures. Following airway occlusion one generally sees a rapid change in airway opening pressure, Pinit, which reflects the resistive pressure drop across the system, followed by a secondary, slower pressure change, Pdif, which reflects the tissue visco‐elastic properties together with any redistribution of gases occurring between lung units at different pressure at the time of interruption. Physical factors in the measuring equipment, i.e., the time taken for valve closure and the presence of a proximal compliant compartment, can cause errors in the calculation of resistance and elastance using the interrupter technique. A computer model was used to determine the effects of these factors on the calculation of resistance and elastance in normal infants, premature infants, and infants with bronchopulmonary dysplasia. The elastance from 25 ml of dead space gas did not introduce significant errors into the measurements in any group of infants, but the presence of an unsupported upper airway caused errors of up to 245%. Increasing valve closure time introduced progressively larger errors into the calculation of resistance and elastance. To keep these errors acceptably small, an occlusion valve should close in 20 ms or less.
Effect of terfenadine on the response to exercise and cold air in asthma
Authors: Wiebicke Wolfram , Poynter Aven , Montgomery Mark , Chernick Victor , Pasterkamp Hans
Published: March 2007

To assess the role of histamine as a mediator in the response to exercise and isocapnic hyperventilation of cold air (IHCA) in asthma, we studied nine asthmatic subjects, age 13 to 25 years. All had exercise induced asthma (EIA) and positive responses to IHCA. Baseline lung function was measured before standardized challenges with histamine, exercise and IHCA. On separate days, these tests were repeated 3 h after a single oral dose of 120 mg terfenadine (TF). Histamine responsiveness decreased significantly, with a provocative concentration, producing a ± 20% fall in FEV1 (PC20), of 1.1 ± 0.8 mg/ml (mean ± SEM) before and 12.0 ± mg/ml after the antihistamine. EIA was significantly less after TF, with 53 ± 5% mean maximal falls in FEV1 from baseline before, and 29 ± 9% after treatment (P < 0.01, paired t‐test). In contrast, the effect of TF on the response to IHCA was insignificant, with mean maximal falls of 45 ± 7% in FEV1 before, and 41 ± 7% after treatment. There was a correlation between PC20 and lowest FEV1 (% predicted) for EIA (r = 0.56, P < 0.05), but not for IHCA (r = 0.34, NS). This study indicates a role of histamine as a mediator in EIA but not in IHCA, supporting different mechanisms for both stimuli.
Short‐Term variability of pulmonary function tests in infants with bronchopulmonary dysplasia
Authors: Nickerson Bruce G. , Durand David J. , Kao Lily C.
Published: March 2007

We determined the short‐term variability of pulmonary function in infants recovering from bronchopulmonary dysplasia. Sixteen infants with birth weight of 1,231 ± 929 grams (mean ± SD) and gestational age of 29 ± 4 weeks were studied twice at 17 ± 8 weeks postnatally at intervals of 4 to 8 days during a period of clinical stability. The infants were still on supplemental oxygen but were off diuretics and bronchodilators.

We used a modification of the rapid thoracic compression method to measure forced expiratory flow (Vmax FRC) and the time constant (τ) of expiratory flow at functional residual capacity. Thoracic gas volume (TGV), mean and total airway resistance (RawM and RawT), and mean and total specific airway conductance (SGawM and SGawT) were measured in a whole body pressure plethysmograph. An esophageal balloon was used to measure dynamic pulmonary compliance (Cdyn). Variabilities were defined as the standard deviation of percent changes between the first and second tests. They were 30% for VmaxFRC, 23% for τ, 12% for TGV, 20% for RawM, 35% for RawT, 25% for SGawM, 72% for SGawT, and 23% for Cdyn. All these tests are useful in assessing pulmonary function of infants with BPD; however, their variability must be taken into account when interpreting short‐term changes.
Changes in pulmonary mechanics following caffeine administration in infants with bronchopulmonary dysplasia
Authors: Davis Jonathan M. , Bhutani Vinod K. , Stefano John L. , Fox William W. , Spitzer Alan R.
Published: March 2007

The effects of caffeine upon pulmonary mechanics were measured in 16 infants with bronchopulmonary dysplasia (BPD). Pulmonary function tests were performed immediately prior to and 1 hour following a dose of 10 mg/kg of caffeine. A 37% increase in minute ventilation (mean ± SEM; 436.6 ± 26.3 to 580.8 ± 30.7 ml/min/kg) was seen with caffeine administration (P < 0.001), primarily from a 42% increase in tidal volume (6.2 ± 0.4 to 8.5 ± 0.4 ml/kg) (P < 0.001). Total lung resistance decreased by 20% (134.6 + 24.2 to 105.3 ± 20.1 cmH2O/L/sec) (P = 0.01), and total pulmonary compliance improved by 47% (0.642 ± 0.104 to 0.908 ± 0.190 ml/cmH2O/kg) (P < 0.01). In five matched control infants with BPD, no effects of placebo upon pulmonary mechanics were detected. Since caffeine has a wide therapeutic index with few side effects, it may be an effective adjunct in the treatment of infants with BPD.
Acute effects of oxygen, nifedipine, and diltiazem in patients with cystic fibrosis and mild pulmonary hypertension
Authors: Davidson Alex , Bossuyt Axel , Dab Isidoor
Published: March 2007

The acute effects of oxygen, nifedipine, and diltiazem were studied in eight patients with cystic fibrosis and mild pulmonary hypertension, to assess the possibility of relieving the latter before the occurrence of irreversible vascular changes. Oxygen decreased pulmonary pressure (− 23%) and resistance (− 21%), while increasing systemic resistance (+ 23%). Nifedipine increased cardiac index (+30%), at the expense of augmented right ventricular work (+ 42%), resulting in a decreased calculated pulmonary resistance (− 23%); pulmonary artery pressure remained unchanged, however. Nifedipine decreased arterial Po2 (− 10%), suggesting ventilation‐perfusion mismatch. Four of the eight patients responded to diltiazem. Their pulmonary pressure (− 35%) and resistance (− 43%) decreased, while systemic vascular tone remained unchanged. Oxygen in three patients, and diltiazem in two, returned pulmonary pressures and resistances to normal values. Early reversal of pulmonary hypertension is possible, and intervention is desirable before the establishment of chronic hypoxia, cor pulmonale, or right ventricular failure. Our data does not support the use of nifedipine in pulmonary hypertension, but shows that oxygen, and in some cases diltiazem, act as effective and selective pulmonary vasodilators.
Effects of inhaled metaproterenol and atropine on the pulmonary mechanics of infants with bronchopulmonary dysplasia
Authors: Kao Lily C. , Durand David J. , Nickerson Bruce G.
Published: March 2007

We evaluated the individual and combined effects of an inhaled beta‐adrenergic agent (metaproterenol) and an inhaled anticholinergic agent (atropine) on the pulmonary function of infants with bronchopulmonary dysplasia. In this randomized, double‐blind study we studied 15 infants at a mean postnatal age of 15.8 weeks (range 4–28 weeks).

On 4 successive days, pulmonary function tests were measured before and after a single treatment with one of the following four aerosols: placebo, metaproterenol, atropine, and combined metaproterenol and atropine. Following treatment with metaproterenol, atropine, and combined metaproterenol and atropine, airway resistance and maximal expiratory flow at functional residual capacity improved significantly when compared with baseline. Pulmonary function values returned toward baseline by 3 hours after the treatments. We found no significant differences between the effects of metaproterenol and atropine and were unable to show any synergy of the two agents.
Wheezing at 8 and 13 years: Changing importance of bronchiolitis and passive smoking
Authors: McConnochie Kenneth M. , Roghmann Klaus J.
Published: March 2007

A group of 153 children (51 with a history of bronchiolitis and 102 matched controls) were evaluated in a historical cohort study at a mean age of 8 years and again at 13 years to test the primary hypothesis that mild bronchiolitis, far more common than severe (hospitalized) bronchiolitis, predicts wheezing. A secondary hypothesis was that passive smoking also predicts wheezing. Many potentially confounding variables such as family history of asthma were controlled in analyses.

Analysis at 13 years produced results that were not anticipated from previous analysis of interviews at age 8. Although mild bronchiolitis was a powerful predictor of wheezing at age 8 years, it was no longer a strong predictor of wheezing at age 13 in either bivariate or multivariate analysis. Although epidemiologic studies, by their nature, cannot prove causality, findings are consistent with the hypothesis that sequelae often follow mild bronchiolitis but diminish during childhood.

Maternal smoking was a powerful predictor of wheezing at age 13 in bivariate analysis (Kendall's Tau B = 0.19, P < 0.01) and in multivariate analysis (odds ratio = 2.67, P < 0.01). In children at highest risk for wheezing, males with a family history of asthma, multivariate analysis suggested that maternal smoking is associated with an increase in wheezing from 36% to 60%. We conclude that passive smoking, previously identified as a risk factor in this population for both bronchiolitis in infancy and wheezing at age 8, is a risk factor for wheezing‐associated morbidity throughout the childhood years.
Comparison of conventional and high‐frequency ventilation in piglets after lung lavage
Authors: Cordero Leandro , Tallman Richard D. , Wasielweski Ray , Rrt Cindy Nissen
Published: March 2007

A piglet model of respiratory failure was used to compare airway pressures required for adequate gas exchange by a conventional positive pressure ventilator (CMV) and a highfrequency pneumatic flow interrupter (HFFI). Twelve newborn piglets (age ± = 3.8 days and weight ± = 1.4 kg) were given saline lung lavages after receiving intravenous Ketamine and Pavulon. Femoral and jugular vessels were catheterized for measurements of aortic and pulmonary blood pressures and gases, cardiac output, hematocrit, glucose and for the infusion of fluids. Airway pressures were measured 5 mm above the distal tip of the endothracheal tube. Lung lavage resulted in decreased static compliance and a twofold increase in pulmonary shunting. Following lavage the animals were kept on 100% oxygen and randomly assigned to either CMV (30/min) or HFFI (600/min) ventilation and thereafter were switched every 30 minutes to the alternate mode. Inspiratory duration was 33% of the total respiratory cycle during CMV and 30–50% for HFFI. Sixteen pairs of data comparing both ventilator modes were used. Blood gases, cardiovascular variables, alveolar‐arterial oxygen gradient, and pulmonary shunting were not different with either ventilator. Positive end‐expiratory pressure (5.3 and 5.6 cm H2O) and mean airway pressure (12.5 and 11.9 cm H2O) were equal for CMV and HFFI, respectively. Peak inspiratory pressure was significantly lower for HFFI (23.1 ± 3.7 SD cm H2O) than for CMV (30.4 ± 5.5 SD cm H2O). The lower peak inflation pressure required during HFFI ventilation may reduce the potential for lung rupture.
Hypercapnia in relation to pulmonary function in duchenne muscular dystrophy
Authors: Canny Gerard J. , Szeinberg Amir , Levison Henry , Koreska Jan
Published: March 2007

Arterialized blood gases were analyzed in 143 patients with Duchenne muscular dystrophy (DMD) to assess the relationship between forced vital capacity (FVC) and hypercapnia. The majority of patients studied had Paco2 values in the low or normal range. Only six older patients had hypercapnia (Paco2 ≥ 45 mm Hg), and all these patients had FVC values ⩽ 40% predicted. We conclude that hypercapnic respiratory failure occurs as a late preterminal event in DMD.
Bronchodilation from intravenous theophylline in patients with cystic fibrosis: results of a blinded placebo‐controlled crossover clinical trial
Authors: Pan Pharmd, Ms Shi‐Hui , Canafax Daniel M. , Cipolle Robert J. , Uden Donald L. , Le Chap T. , Warwick Warren J.
Published: March 2007

Most patients with cystic fibrosis (CF) eventually develop chronic obstructive pulmonary disease and theoretically could benefit from theophylline therapy. The purpose of this study was to investigate the pharmacologic response to intravenous theophylline by pulmonary function tests (PFT) and the theophylline pharmacokinetics in patients with CF. A randomized, double‐blind, placebo‐controlled, crossover trial was conducted in 10 ambulant patients with CF (5 females, 5 males), aged 11 to 21 years. Each patient received an intravenous dose of theophylline and normal saline over 1/2 hour on consecutive days. Spirometry and whole‐body plethysmography were performed at baseline, 1, 3, 5, and 7 h after the theophylline dose, and 10 blood samples were collected over 9 h on both study days. The percent change of PFT from the baseline was recorded. Analysis of variance for balanced two‐period crossover design was used to evaluate the effectiveness of theophylline therapy. The serum concentration (Conc.) vs. time data were fitted using nonlinear least‐squares regression analysis. The theophylline dose administered was 7.9 ± 0.4 (mean ± SD) mg/kg, which produced a maximal Conc. (Cmax) of 14.6 ± 2.7 m̈g/ml. The half‐life (T1/2), volume of distribution (Vd), and total body clearance (TBC) were 4.9 ± 1.9h, 537 ± 124 mL/kg, and 80 ± 16 ml/h/kg, respectively. The results of PFT data analysis indicated that maximal improvement in PFT was observed at 5 h, and statistically significant improvements occurred in forced expiratory flow during the first .75 s (FEV.75), FEV1.0, FEV1.0/vital capacity (VC), FEF when 50% and when 75% of VC is expired, and FEF between 25% and 75% of VC (P <0.05). These results suggest that in CF patients, theophylline can produce a delayed but significant improvement in PFT.
Effect of cyclic adenosine monophosphate elevations on functional responses of polymorphonuclear leukocytes from patients with cystic fibrosis
Authors: Suter Susanne , Chevallier Isabelle , Krause Karl H. , Lew Daniel P.
Published: March 2007

Recently, it has been suggested that the primary metabolic defect of cystic fibrosis (CF) is in the metabolic steps between an elevation of cyclic adenosine monophosphate (cAMP) and the opening of the CI−ion channel in airway epithelial cells. Results from other studies have indicated that the primary defect may also be present in polymorphonuclear leukocytes (PMNL). In PMNL, cAMP is a potent inhibitor of cell function. We therefore used three compounds (epinephrine, theophylline, and forskolin) known to elevate cAMP in PMNL by three different mechanisms, to study the effect of an elevation of cAMP on various cell functions, such as superoxide production, membrane depolarization, and degranulation of CF patient PMNL and PMNL from healthy individuals. The baseline rates of superoxide production, degranulation, and membrane depolarization were identical for CF and control PMNL. After exposure to epinephrine as well as theophylline plus forskolin, the cell function of CF PMNL was inhibited to the same extent as that of control PMNL. Our results argue against an abnormal response of PMNL from patients with CF to an elevation of cAMP.
Risk factors for the development of posterior subcapsular cataracts in patients with cystic fibrosis and allergic bronchopulmonary aspergillosis treated with corticosteroids
Authors: Majure Marc , Mroueh Salman , Spock Alexander
Published: March 2007

Posterior subcapsular cataracts (PSCC) occur in a high percentage of patients treated with long‐term systemic corticosteroids (Naumann Gott, Apple DJ, eds: Pathology of the Eye.New York: Springer‐Verlag, 1986). Fifteen patients with cystic fibrosis treated at Duke University Medical Center between January 1982 and October 1987 required prednisone for treatment of allergic bronchopulmonary aspergillosis (ABPA). Two of these patients (13.3%) were noted to have PSCC during prednisone therapy. We retrospectively examined factors associated with steroid administration that may have been predictive of the development of PSCC in these patients including: 1) steroid therapy for longer than 2 years, 2) steroid dose of 10 mg/day or greater for longer than 6 months, 3) steroid dose of 40 mg/day or greater for longer than 2 months, and 4) change in linear growth pattern during steroid therapy. None of these factors predicted the risk of developing PSCC. Therefore, we recommend that all patients with cystic fibrosis who receive steroids for the treatment of a concomitant condition such as ABPA should undergo careful examination for opacities of the ocular lens at each clinic visit regardless of the duration or dose of steroids.
Use of maximal expiratory flows to evaluate central airways obstruction in infants
Authors: Tepper Robert S. , Eigen Howard , Brown John , Hurwitz Roger
Published: March 2007

Partial expiratory flow‐volume (PEFV) curves obtained by the rapid compression technique were employed to assess airway function in three infants with three different lesions of the central airways (vascular ring, congenital tracheal stenosis, subglottic polyp). Preoperatively, all three demonstrated severe flow limitation with a relativity constant forced expiratory flow over the tidal volume range. Postoperatively the PEFV curves changed to a normal convex shape, and the maximal expiratory flows at functional residual capacity (VmaxFRC) returned to normal. The PEFV curve adds to our physiologic assessment of the severity of the central airway obstruction in infants and to the efficacy of our therapeutic intervention.
Comparison of high‐frequency oscillatory ventilation and high‐frequency jet ventilation in cats with normal lungs
Authors: Boros Stephen J. , Mammel Mark C. , Coleman J. Michael , Horcher Phillip , Gordon Margaret J. , Bing Dennis R.
Published: March 2007

Four adult cats received alternating high‐frequency oscillatory ventilation (HFOV) and high‐frequency jet ventilation (HFJV) at equivalent proximal airway pressures. Physiologic measurements were made before and after each ventilator change. Proximal airway pressures were then adjusted as necessary to reestablish normal pH and Pa values. Aortic, pulmonary artery, and central venous pressures were monitored. Cardiac outputs were measured. Pulmonary and systemic vascular resistance, intrapulmonary shunt, and alveolar‐arterial oxygen gradient were determined. Following the change from HFOV to HFJV at similar proximal airway pressures, HFJV always produced higher pH values (P < 0.0001), higher Pa values (P < 0.05), lower Pa values (P < 0.0001), as well as higher cardiac outputs (P < 0.01), lower pulmonary artery pressures (P < 0.001), and lower pulmonary vascular resistances (P < 0.001). Following the reciprocal crossover, from HFJV to HFOV, HFJV pH values were again higher (P < 0.001), and Pa values were again lower (P < 0.001). A comparison of HFOV and HFJV at similar pH and Pa values showed that HFOV consistently required higher peak inspiratory pressures (P < 0.001), higher mean airway pressure (P < 0.001), and higher pressure wave amplitudes (P < 0.001). Under the circumstances of this study, HFJV produced better gas exchange at lower proximal airway pressures. Pediatr Pilmonol. 1989; 7:35–41.
Long‐term effects of inhaled tobramycin in patients with cystic fibrosis colonized with Pseudomonas aeruginosa
Authors: Maclusky Ian B. , Gold Ronald , Corey Mary , Levison Henry
Published: March 2007

Twenty‐seven patients with cystic fibrosis and endobronchial colonization with Pseudomonas aeruginosa were randomly assigned to inhale either 2 mL saline (12 patients) or 80 mg tobramycin solution (15 patients) 3 times daily. One control patient died; all others completed the study (mean duration 32 months). No significant differences were found between the two groups at enrollment. The treatment group showed no change, while the control group had a significant decline in both pulmonary function and clinical status over the study period. Individually, 11 of 12 patients in the control group showed deterioration, while 9 of 15 in the treatment group either did not change or actually improved (P < 0.01). Thirty‐three percent of patients in the treatment group with susceptible P. aeruginosa at enrollment acquired resistant organisms. There was no evidence of significant nephro‐ or ototoxicity. Although inhaled tobramycin appeared to arrest the decline in pulmonary status, further work is required to identify patients most likely to respond. Pediatr Pilmonol. 1989; 7:42–48.
Transplacentally acquired caffeine and the occurrence of apnea, bradycardia, and periodic breathing in preterm infants: Preliminary communication
Authors: McCulloch Kristine M. , Braun Richard J. , Simms Patricia E. , Evans Michael A. , Kelly Dorothy H.
Published: March 2007

Cord blood caffeine concentrations were measured by high‐pressure liquid chromatography in 79 preterm infants. Eleven infants (14%) had detectable Caffeine concentrations ranging from 1.1 to 3.7 μg/mL X SD = 2.5 ± (0.8), and 68 infants had no measurable caffeine. Seven infants with detectable caffeine (group 1) had impedance pneumograms recorded before 2 weeks of age. Each infant in group 1 was matched with two infants without detectable caffeine by birthweight, gestational age, and chronologic age at pneumogram recording to yield a control group (group 2) of 14 infants. Comparison of the groups using quantitative measures of apnea, bradycardia, and periodic breathing obtained from pneumogram analysis and the incidence of monitor alarms on bedside nursing records showed no significant differences. Thus, caffeine was present infrequently and at low concentrations at birth in 79 preterm infants. The amount of apnea, bradycardia, and periodic breathing experienced before 2 weeks of age in 7 preterm infants with detectable cord blood caffeine was not different from that in 14 similar infants without caffeine. Future studies are planned to examine the relationship between postnatal changes in transplacentally acquired methylxanthine concentrations and quantitative measures of apnea, bradycardia, and periodic breathing in a larger number of preterm infants without cardiorespiratory disease. Pediatr Pilmonol. 1989; 7:66–70.
Expiratory muscle activity in anesthetized children: Effect on the single breath technique
Authors: Shulman David L. , Volgyesi George A. , Burrows Frederick A. , Lerman Jerrold , England Sandra J.
Published: March 2007

Phasic expiratory activity of the abdominal muscles occurs in adults during halothane anesthesia, but has not been demonstrated in children. If present, abdominal muscle activity would preclude the use of recently developed tests of respiratory mechanics in children during anesthesia. We therefore measured abdominal muscle activity throughout induction of anesthesia with halothane in 10 patients between 1.5 and 9.5 years of age, seven with normal respiratory function and three with chronic airway obstruction. During induction of anesthesia with halothane in N2O and oxygen, the abdominal wall electromyograph (a‐EMG) was continuously recorded from surface electrodes. At the same time, the expiratory time constant (τa) was measured using the single breath test (SBT). The patients were then paralyzed with succinyl choline, and the a‐EMG signal and expiratory time constant during paralysis (τP) were recorded. The raw a‐EMG signal and its moving time average were compared with the phase of respiration and with the end‐tidal fraction of halothane (Fehalo), and the effect of abdominal muscle activity on τa was noted. Of the 10 patients, 2 had no abdominal muscle activity at any time during induction. Of the remaining 8 patients, 3 had continuous abdominal muscle activity throughout induction, including one patient with asthma. In the remaining five patients, abdominal muscle activity was present during light halothane anesthesia and disappeared at increased Fehalo. When abdominal muscle activity was present, τa was significantly less than τρ. It is concluded that abdominal muscle activity in expiration is undetectable during deep halothane anesthesia in most children. But abdominal muscle activity persists throughout halothane induction in some children, and, when this occurs, there is an apparent decrease in τa, invalidating the SBT as a test of passive respiratory mechanics. Pediatr Pilmonol. 1989; 7:82–88.