bluuebunny/crossref_metadata_2025 huggingface dataset:
Pseudomonas hyperimmune globulin passive immunotherapy for pulmonary exacerbations in cystic fibrosis
Authors: van Wye John E. , Collins Michael S. , Baylor Marjorie , Pennington James E. , Hsu Yao‐Pi , Sampanvejsopa Vic , Moss Richard B.
Published: March 2007

We studied the effect of an intravenously administered gamma globulin [Ps‐ivlG] enriched fivefold over conventional ivlG for Pseudomonas aeruginosa lipopolysaccharide [PA LPS] antibodies on ten patients with cystic fibrosis [CF] aged 19–32 years during hospitalization for pulmonary deterioration. All were colonized with ≥1 PA phenotype resistant to all antibiotics at the time of admission and they received 500 mg/kg Ps‐ivlG intravenously as a single dose in addition to conventional treatment, including antibiotics and chest physiotherapy. No adverse effects occurred. Circulating immune complexes and complement levels remained unchanged from baseline. Serum levels of anti‐PA LPS lgG, as measured by ELISA for eight PA LPS immunotypes, increased to 244 ± 65% (mean ± SE) of baseline levels 1 hour post‐infusion (P < 0.01), remained significantly elevated during a mean hospital stay of 17 days, and returned to near baseline by follow‐up 4 weeks after hospital discharge. Plasma half‐life and clearance values were similar to those of other subjects receiving conventional ivlG. Sputum PA density declined from 3.0 to 1.2 × 108 cfu/mL 1 week post‐infusion (P ≌ 0.05), and returned to baseline at follow‐up. Serum anti‐PA opsonic activity increased after infusion (P < 0.01), but returned to baseline by 72 hours. Clinical scores improved from admission to discharge (P < 0.005) without decline at follow‐up. Forced vital capacity [FVC] and forced expiratory volume in one second [FEV1] increased from admission to discharge (P < 0.01 and P < 0.05, respectively) without decline at follow‐up. Using autologous historical control data, standard hospital therapy without Ps‐ivlG resulted in no improvement in FVC or FEV1, and a subsequent decline in these parameters (P < 0.05 for each) during a similar follow‐up period. This occurred despite the fact that half the patients did not have antibiotic‐resistant PA on the control admission. We conclude that Ps‐ivlG is a safe adjunctive therapy for pulmonary exacerbations in moderately ill cystic fibrosis patients colonized with resistant PA, and may be associated with both greater and more prolonged improvement in pulmonary function than standard therapy alone. Pediatr Pulmonol 1990; 9:7–18.
Compliance, alveolar–arterial oxygen difference, and oxygenation index changes in patients managed with extracorporeal membrane oxygenation
Authors: Brudno D. Spencer , Boedy R. Frederick , Kanto William P.
Published: March 2007

Eighteen patients with meconium aspiration syndrome who failed conventional management were treated with extracorporeal membrane oxygenation (ECMO) for reversible respiratory failure. Dynamic lung compliance measurements were made prior to, during, and after ECMO support. P(A‐a)O2 and oxygenation index (Ol) measurements were calculated prior to and after ECMO support. Lung compliance decreased significantly comparing before‐ECMO to during‐ECMO, and increased significantly comparing during‐ to after‐ECMO, but not comparing before‐ to after‐ECMO measurements. P(A‐a)O2 and Ol decreased significantly from before to after ECMO. The improvement in oxygenation allowing removal from ECMO does not appear to be related to improved pulmonary mechanics, but may rather be secondary to increased effective pulmonary capillary blood flow. Pediatr Pulmonol 1990; 9:19–23.
Varying tracheal cross‐sectional area during respiration in infants and children with suspected upper airway obstruction by computed cinetomography scanning
Authors: Newth Christopher J. L. , Lipton Martin J. , Gould Robert G. , Stretton Mark
Published: March 2007

An ultrafast cinetomography computed tomographic scanner (cine‐CT) was used to evaluate infants and children (n = 15) with suspected obstruction of the larynx or trachea. One scan sequence provided a single image at each of eight cross‐sectional levels (volume‐mode study). Each study, lasting 224 ms, covered the distance between the supraglottic area and the carina. Each patient also underwent a “dynamic” study at a specific level of interest determined from the volume‐mode study. Forty images within 2.3 s covered at least one respiratory cycle. The images were displayed as a closed‐loop movie and dynamic changes in laryngeal and tracheal caliber with respiration were monitored and quantitated. Tracheal boundaries were outlined either by a trackball‐guided cursor (freehand) or semi‐automated computer edge detection, and cross‐sectional areas and diameters were determined. Reproducibility was tested among three investigators' freehand drawings and two automated computer drawings, at the same and at varying image intensities. The coefficient of variation for the computer‐assisted records (0.2%) was smaller than for the best freehand drawing (1.5%). Tracheal diameters were reproducible, but with greater intra‐individual investigator variability. Four normal tracheas had close to published measurements with conventional CT scanners. Cine‐CT gives objective tracheal dimensions and their variation during respiration; it provides good anatomical detail above the carina, and also of the extra‐ and intra‐thoracic vessels if injected with contrast medium. Pediatr Pulmonal 1990; 9:224–232.
Pneumocystis carinii pneumonia in young children with AIDS
Authors: Bye Michael R. , Bernstein Larry J. , Glaser Joy , Kleid David
Published: March 2007

We present our experience with 54 episodes of Pneumocystis carinii pneumonia in 50 young children with AIDS, all but one representing congenitally acquired infection. Findings at history and physical examination are not helpful in suggesting the diagnosis. The diagnosis is suggested by marked hypoxemia, diffuse disease on chest radiograph, and elevated serum LDH level. Because important aspects of the history may be withheld, a high index of suspicion may be necessary for the correct diagnosis. The mortality rate for ventilated patients was 50%. Pediatr Pulmonal 1990; 9:251–253.
The effect of triclofos sodium sedation on respiratory rate, oxygen saturation, and heart rate in infants and young children
Authors: Jackson E. A. , Rabbette P. S. , Dezateux C. , Hatch D. J. , Stocks J.
Published: March 2007

Chloral hydrate is frequently used to sedate infants for lung function testing. While no effect on respiratory function has been demonstrated, a recent study has reported a fall in oxygen saturation (Sa) following sedation in wheezy infants. This study was designed to assess the effects of the closely related but less gastrically irritant drug triclofos sodium on respiratory rate (RR), heart rate (HR), and Sa in infants without cardiopulmonary disease. Paired measurements using respiratory inductance plethysmography and pulse oximetry were obtained in 10 infants (4–19 months of age) during natural and sedated sleep. Following sedation with triclofos, mean RR rose by 1.9 breaths min−1 (95% confidence intervals [Cl] of the mean difference: 0.13–3.7 min−1). Mean heart rate rose by 5.5 beats min−1 (95% Cl: −0.9–11.9 min−1). Mean Sa fell by 0.68% (95% Cl – 1.8–0.45%). None of these changes are considered to be of clinical importance, and only the change in RR reached statistical significance at the 5% level. Pediatr Pulmonol 1991; 10:40–45.
Morphometric and biochemical changes in lungs of growing rats treated with a calmodulin antagonist
Authors: Ofulue Anwuli F. , Sekhon Harman , Cherukupalli Kamala , Khadempour Hassan , Thurlbeck William M.
Published: March 2007

To determine the role of calmodulin in postnatal lung growth and development, 4‐week‐old rats were injected intraperitoneally on consecutive days with trifluoperazine (TFP), a potent and specific calmodulin antagonist, for a period of 3 weeks and studied in comparison with normal controls and undernourished weight‐matched animals. TFP treatment resulted in stunting of lung growth such that observed normal increments in morphometrically determined total number of alveoli and alveolar surface area and in biochemically determined DNA, elastin, and collagen contents of the lungs were diminished in comparison with age‐matched normal controls. However, the TFP treatment also resulted in reduced daily food intake and body weight gain. In the TFP group, lung weight and lung volume were also reduced compared with the weight‐matched control group. This resulted in reduced alveolar surface area, total number of alveoli, DNA, collagen, and elastin in the TFP group compared with values in the weight‐matched controls. Thus the TFP‐induced lung changes were not due to inanition and/or reduced somatic growth. The TFP treatment resulted in reduced activities of calmodulin and cyclic adenosine monophosphate (cAMP)‐phosphodiesterase in the lungs of the animals, independent of their nutritional status. Based on these findings, we suggest that calmodulin may be an important regulatory component of postnatal lung growth and development. Pediatr Pulmonol 1991; 10:46–51.
Effect of infant position on breath amplitude measured by transthoracic impedance and strain gauges
Authors: Baird Terry M. , Neuman Michael R.
Published: March 2007

Continuous monitoring of respiration by transthoracic electrical impedance gives a signal that has certain not well understood irregularities. Among them is a change in the amplitude of the signal when there is no apparent change in the infant's tidal respiration. One factor that could hypothetically account for alterations of the impedance signal is a change in current path through the thorax secondary to a change in body position. To test this hypothesis we have studied the relationships between breath amplitude measured by transthoracic impedance, one strain gauge on the chest and one on the abdomen, and tidal volume by integrated flow in four body positions. Median breath amplitude was found to vary significantly with body position according to the measuring device. The median impedance breath amplitude increased by 27% in the supine position compared with the prone position, with no associated change in tidal volume. Differences in the strain gauge signal amplitude for these positions were not statistically significant. Correlation between breath amplitude measured by impedance changes and tidal volume was minimal (r = 0.114). These results indicate that infant position affects impedance breath amplitude independently of changes in tidal volume. Pediatr Pulmonol 1991; 10:52–56.
Respiratory tract colonization with Pseudomonas aeruginosa in cystic fibrosis: Correlations between anti‐Pseudomonas aeruginosa antibody levels and pulmonary function
Authors: Winnie Glenna B. , Cowan Robert G.
Published: March 2007

Chronic Pseudomonas aeruginosa respiratory tract colonization in patients with cystic fibrosis is associated with development of antibodies to the organism. In contrast to the protection usually afforded by humoral immunity to a bacterial pathogen, the immune response to P. aeruginosa may help perpetuate infection and contribute to pulmonary damage in cystic fibrosis. To determine if specific anti‐P. aeruginosa antibody levels correlated with pulmonary dysfunction, we measured antibodies to seven P. aeruginosa serotypes, and correlated the geometric mean titer with pulmonary function tests. Patients were divided into groups without P. aeruginosa colonization (n = 20), with recent colonization (n = 20), and with chronic colonization (n = 60). Noncolonized patients had normal pulmonary function or mild obstructive lung disease, and low anti‐P. aeruginosa titers. Pulmonary function tests in recently colonized patients were not different from those of noncolonized patients, but antibody titers were higher. Following colonization FEV1 declined and titers increased rapidly. Patients with chronic colonization had worse pulmonary function and higher titers, but while the former were stable the latter gradually increased. An inverse correlation was found between anti‐P. aeruginosa titer and FVC, FEV1, and FEF25–75 (P < 0.001) in these patients; age was not a factor. The strong correlation between severity of lung disease and anti‐P. aeruginosa titer demonstrates that an exaggerated immune response to P. aeruginosa is associated with pulmonary damage in patients with cystic fibrosis. Pediatr Pulmonol 1991; 10:92–100.
Delivery of aerosolized medication to intubated babies
Authors: Watterberg Kristi L. , Clark Andrew R. , Kelly H. William , Murphy Shirley
Published: March 2007

We studied the delivery of aerosolized cromolyn sodium to intubated babies, and evaluated the effect of changes in delivery techniques. In addition, we compared these results with an in vitro model of aerosol delivery. Cromolyn sodium was used as a marker because once the drug is absorbed, it is excreted unchanged, approximately 50% in urine and 50% in bile. We demonstrated that, in vitro, a conventional, jet‐type nebulizer aerosolized 20.5% of a test dose of cromolyn, and only 5.5% of the dose was recovered after passage through 60 cm of ventilator tubing and an endotracheal tube adapter. This increased to 44.5% nebulized and 19% recovered when the volume nebulized was increased from 2 mL to 5 mL. A submicronic nebulizer aerosolized 40% and delivered 33.5% of the test dose. A 20 mg dose of nebulized cromolyn sodium was used as a test dose in infants, after which urine was collected for 4 hours. Forty‐three urine samples were collected, after the delivery of cromolyn test doses, from nine babies (16–128 days old) intubated for bronchopulmonary dysplasia. Both the jet and submicronic nebulizers were tested in two positions: (1) in place of the ventilator humidifier, and (2) at the endotracheal tube adapter. There were no statistically significant differences in cromolyn delivery for any system configuration. In all situations, means of less than 0.1% of the test dose were recovered in the urine. We estimated that in all cases, < 1% of the test dose (approximately 50–100 μg of cromolyn) had been deposited in the lung. These results show that although the submicronic nebulizer aerosolized cromolyn more efficiently, no additional cromolyn could be detected in infants. We speculate that a significant portion of the smaller particles are exhaled. Pediatr Pulmonol 1991; 10:136–141.
Differential effects of oxygen and barotrauma on lung injury in the neonatal piglet
Authors: Davis Jonathan M. , Dickerson Bryon , Metlay Leon , Penney David P.
Published: March 2007

In order to differentiate the effects of hyperoxia and barotrauma in the pathogenesis of acute neonatal lung injury, piglets were either hyperventilated (Pa, 15–20 torr) for 48 hours with 100% oxygen (Group I), hyperventilated with 21% oxygen (Group II), normally ventilated (Pa, 40–45 torr) with 100% oxygen (Group III), or normally ventilated with 21% O2 (Group IV) and compared to unventilated controls. Pulmonary function was tested, and biochemical indicators of lung injury were analyzed in tracheo‐bronchial aspirates at 0, 24, and 48 hours. Bronchoalveolar lavage fluid was analyzed for surfactant composition and activity at the end of the study. At 48 hours, hyperoxic, hyperventilated piglets had significantly decreased dynamic lung compliance (30%) and increased pulmonary resistance (16%), aspirate cell count (190%), elastase activity (88%), albumin (214%), and total protein (150%) concentration. Qualitative light microscopy showed moderate to severe atelectasis, fibrinous exudate, edema, and inflammation. Normoxic, hyperventilated animals had comparable changes in pulmonary mechanics, but significantly milder cellular, biochemical, and morphologic changes. In hyperoxic, normocarbic animals pulmonary physiologic, cellular, and biochemical variables changed comparably to hyperoxic, hyperventilated animals; the pathologic changes were intermediate between hyperoxic, hyperventilated and normoxic, hyperventilated piglets. Normoxic, normocarbic animals had no significant changes in most variables over 48 hours; on morphologic examination their lungs were similar to unventilated controls and showed only mild edema. Surfactant had normal biophysical activity in all animals. Our results demonstrate that hyperoxia causes more significant physiologic, inflammatory, and histologic changes than barotrauma alone. Future attempts to prevent lung injury in neonates should be directed primarily at oxygen toxicity. Pediatr Pulmonol 1991; 10:157–163.
Airway pressures during crying: An index of respiratory muscle strength in infants with neuromuscular disease
Authors: Shardonofsky Felix Roberto , Perez‐Chada Daniel , Milic‐Emili Joseph
Published: March 2007

The purpose of this study was to assess the strength of the respiratory muscles in 12 infants with neuromuscular disease (age range: 0.17–2.08 years) by measuring the maximal inspiratory and expiratory airway pressures (PImax and PEmax) during crying efforts. Infants were divided into two groups according to their respiratory history. Group A included six infants in stable condition without clinical evidence of respiratory abnormalities, and Group B included six infants with severe generalized muscle weakness and previous respiratory failure. The infants in Group B had been weaned from mechanical ventilation 6 to 14 days before being studied. For infants of Group A, PImax and PEmax values were 77 ± 28 cmH2O and 62 ± 18 cmH2O, respectively; for infants of Group B, they were 38 ± 8 cmH2O and 34 ± 8 cmH2O, respectively. A positive correlation was found between PEmax and body mass percentile. No infant had hypercapnia at the time of the study, and Pa values in infants of Group B were significantly lower than those of Group A. These results suggest that measurements of airway pressures during crying may provide an index of respiratory muscle strength in infants with generalized muscle weakness. Pediatr Pulmonol 1991; 10:172–177.
Benefits and complications of troleandomycin (TAO) in young children with steroid‐dependent asthma
Authors: Flotte Terence R. , Loughlin Gerald M.
Published: March 2007

In nine children with steroid‐dependent asthma, ranging in age from 2 and 11/12 to 14 and 4/12 years, troleandomycin (TAO) was administered at a dose of 250 mg po QD or BID, along with oral methylprednisolone. Both medications were then rapidly changed to a QOD schedule. Baseline daily steroid dosage requirements decreased from 15.3 ± 9.1 mg methylprednisolone to 1.4 ± 0.7 mg (P < 0.01, paired t‐test), and the number of steroid bursts (1–2 mg/kg/day) per year decreased from 12.2 ± 4.8 to 4.1 ± 2.0 (P < 0.01, paired t‐test). There was also a significant decrease in the number of hospitalizations per year from 3.4 ± 4.6 to 0.6 ± 0.7 (P < 0.05, paired t‐test). The incidence of steroid side effects increased, despite the decrease in the amount of steroid required. Specifically, the prevalence of cataracts increased from 11% to 33% (χ2 = 4.5, P = 0.15) and the prevalence of hypercholesterolemia increased from 22% to 78% (χ2 = 16.67, P < 0.001). There was no elevation of serum transaminases in any of our patients on TAO. Although TAO appears to be efficacious, caution is warranted when TAO is considered for use in younger children with steroid‐dependent asthma. Pediatr Pulmonol 1991;10:178–182.
Use of exercise in the management of cystic fibrosis: Short communication about a survey of cystic fibrosis referral centers
Authors: Kaplan Ted A. , Zebranek James D. , McKey Robert M.
Published: March 2007

A survey of 47 cystic fibrosis referral centers was conducted to study the use of exercise in the management of patients with cystic fibrosis (CF). A questionnaire with 5 brief questions concerning the prescription and application of exercise therapy was sent to the first 47 centers (38.5%) listed in the 1988 CF Foundation Directory, and 46 (97.9%) were returned. While all but one of the respondents recommend exercise at least to selected patients, and while 80.4% of the centers refer patients to summer camp programs, only 43.5% offer exercise stress testing and only 21.7% offer an exercise program for their patients. Most of the respondents who recommend exercise prescribe aerobic exercise, swimming being the most frequently chosen type. Although there is a large discrepancy between those centers that acknowledge the benefits of exercise and those that have arranged for regularly available exercise services, inroads have been made in utilizing this therapeutic tool for patients with CF. Pediatr Pulmonol 1991; 10:205–207.
Bacterial infection in under school age children with expiratory difficulty
Authors: Korppi Matti , Leinonen Maija , Koskela Markku , Mäkelä P. Helena , Saikku Pekka , Launiala Kari
Published: March 2007

Serological evidence of bacterial infection was prospectively studied in less than 6 years old patients during 188 acute episodes of expiratory difficulty requiring hospital treatment. Such evidence indicated by antibody or antigen assays was found in 40 patients (21%). Streptococcus pneumoniae was identified in 25 cases; antigenemia was found in 10, antigenuria in 2 and seroconversion in 14 cases. Seroconversion to nontypable Haemophilus influenzae was found in 9 and to Branhamella catarrhalis in 2 cases. Seroconversion to Chlamydia spp. was demonstrated in 8 patients, but specific tests for C. trachomatis were negative. C‐reactive protein was over 40 mg/L in 35 patients (19%); serological evidence of bacterial infection was present in 14 and absent in 21 of them. Thus, either serological evidence of bacterial infection or an elevated C‐reactive protein was found in 61 of the 188 cases (32%). We conclude that bacterial infection is commonly associated with acute wheezing in children under school age. We suggest that bacterial, as well as viral, infections may trigger an acute obstructive attack in children with reactive airways. Pediatr Pulmonol 1991; 10:254–259.
Predicted values for lung diffusing capacity in healthy children
Authors: Nasr Samya Z. , Amato Patricia , Wilmott Robert W.
Published: March 2007

Lung diffusing capacity was measured in 92 healthy Caucasian children (52 boys and 40 girls), ranging in age from 6 to 17 years, using the single breath carbon monoxide technique (DLCO). Multiple regression equations were developed to predict the DLCO value. Standing height, gender, weight, and age were significant factors in the prediction of DLCO. Sitting height was not a significant covariate when standing height was in the model, but it could replace standing height in the equation. Equations are presented for the calculation of predicted DLCO in children based on standing or sitting height, age, sex, and weight. Pediatr Pulmonol 1991; 10:267–272.
Doppler echocardiographic evaluation of pulmonary artery pressure in pneumonia of infants and children
Authors: Jun‐Bao Du , Shu‐Zheng Li , Bao‐Lin Wang , Yuan Li
Published: March 2007

Previously, there was insufficient evidence to confirm that pneumonia in infants and children might lead to the development of pulmonary hypertension. Recently, it has been shown that acceleration time corrected for heart rate (ATc) and the ratios of right ventricular preejection period to right ventricular ejection time (RPEP/RVET) and of right ventricular preejection period to acceleration time (RPEP/AT) derived from Doppler echocardiography correlated well with pulmonary artery pressure (PAP). To approach PAP in patients with infantile pneumonia, we measured RPEP/RVET, RPEP/AT, and ATc in 105 infants and children with pneumonia and in 17 controls, using a commercially available 2‐dimensional echocardiograph (Toshiba SSH‐40A) with SDS‐21B Doppler unit. An increase of varying degrees in both ratios and ATc was noted during acute illness and significant differences in ratios RPEP/RVET and RPEP/AT were found among patients with mild, moderate, and severe disease. This suggested that PAP increased to different extents in the acute stage of illness and that the degree of increase was related to the severity of disease. Pediatr Pulmonol 1991; 10:296–298.
Recurrent respiratory infections in a child with fucosidosis: Is the mucus too thin for effective transport?
Authors: Rubin Bruce K. , Macleod Patrick M. , Sturgess Jennifer , King Malcolm
Published: March 2007

Fucosidosis is caused by a deficiency of the lysosomal enzyme alpha‐L‐fucosidase (ALF) leading to an accumulation of glycoproteins in a variety of cells. Infants and young children with this disorder are prone to recurrent sinus and pulmonary infections and often die of pneumonia. We studied the mucociliary and systemic immune function in a 6 year old girl with fucosidosis and recurrent respiratory infections. All measurements of systemic immune function were normal. Sweat chloride was normal when measured on angiokeratotic skin but was greater than 65 mg/L on uninvolved areas.

During the placement of tympanic ventilation tubes, tracheal mucus was gently aspirated and a mucosal biopsy was taken. Tracheal mucus transport was not measured. The biopsy material was examined under phase contrast microscopy and revealed ciliated cells with apparently normal beating. TEM of these cells showed a characteristic pattern of vacuoles in the cytoplasm as described in other tissues from patients with fucosidosis. Ciliary ultrastructure was normal. Mucus viscoelasticity was measured in a magnetic microrheometer. The loss tangent was 2 SD above the mean for normal mucus and mechanical impedance was about 2 SD below the mean. These changes are similar in direction but double in magnitude to what has been described with methacholine administration in dogs. The high compliance of the mucus may be due to incomplete assembly of mucus glycoprotein or to decreased secretion of glycoproteins in respiratory secretions. This leads to mucus that is abnormally watery and thus difficult to clear from the airway. Pediatr Pulmonol 1991; 10:304–309.
Pulmonary mechanics and outcome of neonates on ECMO
Authors: Freezer N. J. , Butt W. , Sly P. D.
Published: March 2007

Deciding when to wean neonates from extracorporal membrane oxygenation (ECMO) can be difficult. The usefulness of simple measurements of pulmonary mechanics e.g., dynamic compliance (Cdyn) has been questioned. We investigated the pulmonary mechanics of eight neonates using the interrupter technique, which allows the partitioning of pulmonary mechanics into compartments representing the conducting airways and more peripheral phenomena (viscoelastic properties and “pendelluft”).

Three neonates required ECMO for a congenital diaphragmatic hernia (CDH), two for hyaline membrane disease (HMO), two for meconium aspiration syndrome (MAS), and one for pneumonia. All neonates with MAS, HMD, and pneumonia were successfully weaned from ECMO when their Cdyn was 0.3 mL/cmH2O/kg or greater [mean 0.34 ± 0.06 (SEM)]. All three neonates with CDH died and their highest Cdyn was 0.21, 0.19, and 0.09 mL/cmH2O/kg respectively (mean, 0.16 ± 0.037).

The airway resistance (Raw) and the slower component of pressure change after interruption (δPdiff), a measure of the more peripheral phenomena of the lung, were not significantly different in those neonates who survived and those who did not. The values for δPdiff in all patients were higher than those in healthy neonates. However, the Raw was not different. This suggests that the major disturbance in pulmonary mechanics was distal to the conducting airways.

Those neonates who were successfully weaned from ECMO had a significantly higher Cdyn 24–48 hours prior to decannulation. Considering the lung as a two‐compartment model offers no advantages when compared to the one‐compartment model for the prediction of the outcome of a neonate on ECMO.
Inspiratory time and pulmonary function in mechanically ventilated babies with chronic lung disease
Authors: Goldman Steven L. , McCann Ellen M. , Lloyd Benjamin W. , Yup Gary
Published: March 2007

To learn if increasing inspiratory time would improve pulmonary function in mechanically ventilated babies with chronic lung disease, we measured lung mechanics and alveolar ventilation at three inspiratory times: 0.4, 0.6, and 0.8 s. Nine babies were studied. Their mean birth weight was 875 g (range, 570–1,100 g), gestational age 27 (24–34) weeks, and age 7 (4–12) weeks. Their mean oxygen requirement was 40% (29–53), ventilator rate 33/min (20–40), and mean airway pressure 8 (5–10) cmH2O. Ventilator rate was kept constant; therefore expiratory time decreased and mean airway pressure and I:E ratio increased at longer inspiratory times. At 0.6 s and 0.8 s, when compared to 0.4 s, significant increases occurred in tidal volume (10.4, 10.1, and 8.4 mL/kg, respectively), dynamic lung compliance (0.68, 0.68, and 0.53 mL/cmH2O/kg, respectively), and alveolar ventilation (6.0, 6.3, and 4.7 mL/kg/breath, respectively). Airway resistance, anatomical dead space to tidal volume ratio, and functional residual capacity were similar at the three inspiratory times. Our findings suggest that an inspiratory time ⩾0.6 s (compared to 0.4 s) increases the effectiveness of mechanical ventilation for babies with chronic lung disease.
Relationship of symptoms to lung function abnormalities in preterm infants at follow‐up
Authors: Yuksel B. , Greenough A.
Published: March 2007

Recurrent respiratory symptoms are common in preterm infants in the first 2 years of life. The aim of this study was to determine the lung function abnormalities associated with such symptoms. Forty preterm infants, with a median gestational age of 29 weeks were studied at a median postnatal age of 12 months. Twenty‐two suffered from recurrent symptoms, defined as wheezing and/or coughing on at least 4 days per week over the previous month. Lung function was assessed by measurement of functional residual capacity (FRC), using a helium gas dilution technique, and airway resistance (Raw) and thoracic gas volume (TGV) plethysmographically. No significant difference was found in TGV between symptomatic and asymptomatic infants, but the median FRC was lower (P < 0.01), Raw higher (P < 0.01), and FRC:TGV ratio lower (P < 0.001) in the symptomatic infants. These lung function abnormalities in the symptomatic infants are suggestive of gas trapping.
Comparison of FEV1and transcutaneous oxygen tension in the measurement of airway responsiveness to methacholine
Authors: van Broekhoven P. , Hop W. C. J. , Rasser E. , de Jongste J. C. , Kerrebijn K. F.
Published: March 2007

The measurement of airway responsiveness in preschool children is hampered by the fact that most tests of airway caliber are difficult to carry out at a young age. Patient cooperation is only needed to a limited extent when transcutaneous oxygen tension (Ptc) is used as an indicator of airway obstruction following bronchial provocation.

In 51 children, aged 6–14 years with asthma we have measured Ptcand forced expiratory volume in 1 second (FEV1) concurrently after bronchial provocation, using increasing doses of methacholine administered with a De Villbiss 646 nebulizer and a French‐Rosenthal dosimeter.

The shapes of the dose‐response curves to Ptcand FEV1show a close similarity. After methacholine challenge, the decrease in Ptccorrelates highly with the decrease in FEV1.

We conclude that in children a 20% decrease in Ptccan be used as a sensitive indicator of airway narrowing after methacholine challenge.
Effect of nasal CPAP on thoracoabdominal motion in neonates with respiratory insufficiency
Authors: Locke Robert , Greenspan Jay S. , Shaffer Thomas H. , Rubenstein S. David , Wolfson Marla R.
Published: March 2007

Thoracoabdominal motion (TAM) profiles were determined in ten infants requiring nasal continuous positive airway pressure (CPAP) and supplemental oxygen, in order to assess the influence of CPAP on chest wall function in infants with respiratory insufficiency. (TAM) was quantitated by respiratory inductive plethysmography, measuring relative motion of the rib cage and abdomen. Baseline pulmonary function (without CPAP support) was assessed from simultaneous measurements of transpulmonary pressure, air flow, and tidal volume. Measurements of (TAM) were acquired at baseline and at nasal CPAP levels of 0, 3, 5, and 8 cm H2O, in randomized order. Without CPAP, relative paradoxical motion occurred, i.e., the rib cage collapsed inward instead of expanding outward early in inspiration. With CPAP, TAM resembled the pattern in preterm infants, without lung disease. We found that nasal CPAP lowers the phase angle in infants with respiratory insufficiency (P < 0.003), indicating improved synchrony of TAM. In addition, the improvement with nasal CPAP was related to the severity of pulmonary compromise at baseline. We speculate that changes in TAM associated with nasal CPAP arise from an interaction between pulmonary mechanics and an enhanced stability of the chest wall. In this context, the greater synchrony of TAM is suggestive of an improved breathing strategy. This may be a noninvasively obtainable marker of an effective nasal CPAP level in infants with altered pulmonary and chest wall mechanics.
The long‐term effect of high‐frequency chest compression therapy on pulmonary complications of cystic fibrosis
Authors: Warwick Warren J. , Hansen Leland G.
Published: March 2007

A high‐frequency chest compression (HFCC) device for clearance of mucous secretions from airways was tested in 16 cystic fibrosis (CF) patients with significant improvement in pulmonary function for the HFCC period, which averaged 22 months per patient. The device consists of a variable air pulse delivery system and a non‐stretch inflatable vest worn by the patient to cover the entire torso. The patients perform 30 minute therapy sessions divided into 5 minute periods at each of six frequencies. Individual patient therapy time per day ranged from 30 to 240 minutes. Frequencies used by each patient were determined by measuring air flow at the mouth and calculated volume expired per chest compression during tidal breathing while receiving HFCC at frequencies between 5 and 22 Hz at 1 Hz increments. The frequencies that produced the three highest flows and the three largest volumes were selected for each patient's therapy.

Ninety‐four percent of patients' regression line slopes for percent predicted forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) became more positive during self‐administered HFCC therapy as compared to slopes before HFCC therapy, when manual chest physical therapy was used.

Two‐sided t‐test showed that the mean slopes were more positive for FVC and FEV1 during HFCC therapy than for the manual chest physical therapy period before HFCC therapy. The significance level for both FVC and FEV1 was at P < 0.001.
Longitudinal serum IgG response to Pseudomonas cepacia surface antigens in cystic fibrosis
Authors: Aronoff Stephen C. , Quinn Francis J. , Stern Robert C.
Published: March 2007

In cystic fibrosis (CF), serum antibody against surface antigens of Pseudomonas aeruginosa is detected only after colonization. Since pulmonary acquisition of P. cepacia usually follows colonization with P. aeruginosa and since P. aeruginosa‐colonized patients with CF have demonstrable antibody against outer membrane proteins of P. cepacia, it appears that acquisition of the latter organism occurs in the presence of specific serum antibody. To test this hypothesis, serum obtained from six P. aeruginosa‐colonized patients 4 and 2 years prior to and 3 months and 2 years after P. cepacia colonization were assayed for total and specific IgG to P. cepacia outer membrane components. Four patients demonstrated 6‐fold or greater increases in specific IgG titers to whole outer membranes following colonization. By immunoblot, all patients had demonstrable serum IgG against the 27‐ and 36‐kDa outer membrane proteins of P. cepacia 4 and 2 years prior to colonization. Immunoblots after P. cepacia acquisition demonstrated an intensification of the 28‐ and 36‐kDa bands and the appearance of antibody to a very low molecular weight compound which was not hydrolyzed by proteinase K and was present in purified LPS. These observations suggest that low serum titers of antibody against two P. cepacia outer membrane proteins are present in patients with CF prior to P. cepacia colonization, and that these antibodies fail to protect for intrinsic or extrinsic reasons.
Outcome of home care for technology‐dependent children: Success of an independent, community‐based case management model
Authors: Fields Alan I. , Coble Deborah Hardy , Pollack Murray M. , Kaufman Joanne
Published: March 2007

Case management is important for successful home care of technology‐dependent, respiratory‐disabled children. Traditionally, the medical model of hospital‐based home care and case management has been used for these children. The outcome may be different from when using independent, community‐based home care and case management. We evaluated the results of 28 technology‐dependent children [23 receiving mechanical ventilation and 5 receiving continuous positive airway pressure (CPAP)] from 8 hospitals, who utilized an independent, communtiy‐based, case management group to coordinate home care. After 26.3 ± 20.6 months of follow‐up, 13 children (46%) remained technology‐dependent, 10 (36%) were technology‐independent, and 5 (18%), all with neurologic dysfunction, had died. Only one death was caused by a complication of technology. All children with congenital anomalies (n = 4), primary pulmonary disease (n = 8), and neuromuscular disease (n = 4) survived, and 9 (56%) were weaned from technological support. Children with chronic respiratory failure secondary to central neurologic dysfunction (n = 12) did poorly: 5 died, 6 remained technology‐dependent, and only 1 became independent of technology. Children with neuromuscular diseases tended to use less home care nursing at a lower home care cost. Parent satisfaction was high among those who responded (82%), indicating that the child, siblings, and family were better off with the child at home. These outcomes suggest that community‐based home care and case management is a reasonable alternative to the hospital‐based model.
Effect of prenatal cocaine on respiration, heart rate, and sudden infant death syndrome
Authors: Silvestri Jean M. , Long Joyal M. , Weese‐Mayer Debra E. , Barkov Gary A.
Published: March 2007

We studied 114 neonates by pneumocardiogram recordings in order to examine the effects of cocaine with and without opiate exposure on neonatal respiration, heart rate, apparent life threatening events (ALTE), and sudden infant death syndrome (SIDS). In full‐term infants exposed to cocaine without opiates we found increased longest apnea duration and more episodes of bradycardia, but decreased periodic breathing and average heart rate than in control full‐term infants. Term infants prenatally exposed to cocaine with opiates also had less periodic breathing. Preterm infants exposed to cocaine with and without opiates had decreased apnea density and periodic breathing compared with preterm controls. Discriminant analysis to determine whether perinatal asphyxia or exposure to other drugs could predict cardiorespiratory abnormalities showed no consistent relationship. In 72 of 114 infants available for follow‐up, no ALTE occurred but two were lost to SIDS. Our data support the hypothesis that prenatal cocaine exposure may perturb, albeit subtly, the maturation of respiratory control, resulting in disruption of postnatal respiration.
Caffeine potentiates airway responsiveness in the neonatal lamb
Authors: Keklikian Esteban N. , Wolfson Marla R. , Shaffer Thomas H.
Published: March 2007

In contrast to its effect on airway smooth muscle in the adult, in vitro studies have shown that caffeine significantly increases active tension in airway smooth muscle in the neonatal lamb. To determine if caffeine has a physiological effect on airway function during early development, we studied the effect of caffeine on acetylcholine‐induced bronchoconstriction in two groups of neonatal lambs. The animals were anesthetized, paralyzed, and maintained normoxic and normocapnic with mechanical ventilation. Pulmonary mechanics were evaluated as indices of airway tone, and functional residual capacity was used as an index of lung volume; heart rate and mean arterial pressure were used to assess cardiovascular status. Acetylcholine‐induced bronchoconstriction was evaluated as percentage changes of airway conductance and lung compliance from baseline, before and 1 hour after administration of normal saline or caffeine, and it was further analyzed with respect to the dose that produced a 20% change in those values (PD20). There were no significant alterations in baseline lung mechanics, lung volume, or mean arterial pressure following saline or caffeine infusion. However, caffeine produced a left shift in the acetylcholine dose‐response curve for conductance and compliance and a significant decrease (−52%; P < 0.001) in PD20 for conductance. There were no significant alterations in any parameter following saline administration. Since caffeine is used commonly for the treatment of apnea of prematurity, it is noteworthy that caffeine increases airway reactivity at clinically relevant doses. These findings raise important issues regarding the use of caffeine for the treatment of apnea of prematurity.
Mucoid Pseudomonas aeruginosa is a marker of poor survival in cystic fibrosis
Authors: Henry Richard L. , Mellis Craig M. , Petrovic Lea
Published: March 2007

The aim of this study was to assess the prognostic significance of mucoid and non‐mucoid isolates of Pseudomonas aeruginosa (muPs and non‐muPs) from the sputa of patients with cystic fibrosis (CF). Eighty‐one children with CF who coughed up sputum daily were recruited and followed over 12 months with frequent sputum cultures. At the end of this observation period they were classified to one of three age‐matched groups. In 50 mPs was isolated on one or more occasions; 19 grew non‐muPs but not muPs, and 12 grew no isolates of Ps aeruginosa. These 81 children and adolescents were followed for a further 8 years or until they died. Twenty‐one (42%) of the muPs patients died compared with two (11%) of the non‐muPs and one (8%) of the no Ps patients (P < 0.01). Stepwise regression indicated that forced expiratory volume in 1 second (FEV1) had the main predictive effect but that age, Shwachman score and muPs also had a predictive effect. Identification of mucoid forms of Ps aeruginosa is an unfavorable prognostic factor but the isolation of non‐mucoid strains does not appear to be any more important than the isolation of other common respiratory pathogens.
Dexamethasone therapy for bronchopulmonary dysplasia: Improved respiratory mechanics without adrenal suppression
Authors: Brundage K. L. , Mohsini K. G. , Froese A. B. , Walker C. R. , Fisher J. T.
Published: March 2007

The purpose of the present study was to examine the pattern of changes in respiratory system mechanics induced by dexamethasone (Dex) in infants with bronchopulmonary dysplasia (BPD) and to determine whether dosages that produce these changes induce adrenal suppression. We examined mechanics in seven ventilator‐dependent premature infants (age, 33 ± 4.8 days) with BPD, before and daily during Dex therapy. Dex (0.5 mg/kg/day) was given intravenously for 7 days unless complications necessitated early termination. Respiratory system resistance (Rrs) and compliance (Crs) were measured by the passive expiratory flow‐volume technique during the course of dexamethasone therapy or until extubation. Adrenocorticotrophic hormone (ACTH) stimulation tests were done at baseline and following Dex therapy to evaluate adrenal function. Dex therapy caused a 77 ± 18% increase in Crs (from 0.97 ± 0.09 SEM mL/cmH2O to 1.6 ± 0.16 mL/cmH2O; P < 0.025) and a 33 ± 5% decrease in Rrs (from 0.20 ± 0.02 cmH2O/mL/s to 0.14 ± 0.01 cmH2O/mL/s P < 0.01). Concurrently, ventilator rate, mean airway pressure, and FI all decreased significantly (P < 0.025). Extubation occurred later in infants with the lowest Crs and highest Rrs at baseline. At extubation, all Crs values were greater than 1.33 mL/cmH2O and Rrs values were less than 0.15 cmH2O/mL/s. Systolic blood pressure increased from 61 ± 6.3 mmHg to 84 ± 17 mmHg, 72–96 h after the start of Dex (P < 0.025). There were no episodes of culture‐positive sepsis. Neither basal nor ACTH‐stimulated levels of cortisol were suppressed as a result of Dex therapy (P > 0.05). We conclude that correction of abnormalities of compliance is critical to reducing work of breathing and achieving extubation in this population. In the small number of infants we studied, Dex induced this therapeutic response with minimal side effects and no statistically significant change in adrenal function.
Measurement of bronchial responsiveness in young children: Comparison of transcutaneous oxygen tension and functional residual capacity during induced bronchoconstriction and ‐dilatation
Authors: Wilts M. , Hop W. C. J. , van der Heyden G. H. C. , Kerrebijn K. F. , de Jongste J. C.
Published: March 2007

Demonstration of an increased bronchial responsiveness in preschool children may support the diagnosis of asthma. Most young children cannot perform routine lung function tests. Transcutaneous P(Ptc) measurement has been applied successfully in young children, and changes in Ptchave been shown to correlate well with changes in forced expiratory volume in 1 second (FEV1) during bronchoprovocation testing with methacholine. Ptcis, however, an indirect measure of the effect of inhaled spasmogens. As functional residual capacity (FRC) can also be measured by helium dilution spirometry in preschool children, we compared Ptcand FRC during methacholine inhalation challenges and after inhaled terbutaline, in order to determine whether FRC is useful as a more direct measure of induced bronchoconstriction and ‐dilatation than Ptc. We studied 41 allergic asthmatic children (mean age, 5.2 years) who underwent a methacholine bronchoprovocation test; 38 children received terbutaline 1 h after the final methacholine dose. The provocative concentration of methacholine that caused a 20% decrease of Ptcwas determined, and changes in FRC and Ptcafter each methacholine dose step were compared. Similarly, changes in Ptcand FRC before, and 15 and 30 min after, terbutaline were compared. All children had a drop in Ptcafter increasing doses of methacholine; a 20% change was reached in 38 patients. Mean FRC values increased significantly but variably with increasing doses of methacholine, and changes in Ptcand FRC did not correlate. After terbutaline, Ptcincreased slightly but significantly, and FRC again varied unpredictably. In a separate group of 11 children, the effect of terbutaline was assessed directly after the final methacholine dose, when significant bronchoconstriction was still present. In this group, FRC changes were not significant and were not related to the increase in Ptc. Our study suggests that FRC cannot be recommended to monitor the effects of inhaled bronchoconstrictors and bronchodilators in young children. Ptcmeasurement is one of the few convenient and safe methods to be used in children too young to perform conventional tests of lung function during bronchoprovocation testing.