bluuebunny/crossref_metadata_2025 huggingface dataset:
A bench test evaluation of a neonatal closed tracheal suction system
Authors: Monaco Frank J. , Meredith Keith S.
Published: March 2007

We tested the hypothesis that a possible mechanism for reduced hypoxia during suctioning with closed tracheal suction systems (CTSS) is the provision of uninterrupted gas delivery and the maintenance of airway pressures. This was accomplished by using a neonatal ventilator and test lung model to permit the insertion of a CTSS (with and without suction applied), measurements of inspiratory and end‐expiratory airway pressures proximal and distal to the endotracheal tube (ETT) and measurements of inspired and expired tidal volumes (sampled distal to the ETT). An 8 Fr CTSS was evaluated with 4.5, 4.0, and 3.5 mm ETT, and a 6 Fr CTSS with a 3.5, 3.0, and 2.5 mm ETT. We found that catheter placement without suction caused no changes in proximal airway pressures but distal peak inspiratory pressures decreased as the relationship between suction catheter size and ETT lumen increased, while distal end‐expiratory pressures were unchanged. Similarly, distal tidal volumes progressively decreased as the size of the suction catheter occupied more of the ETT lumen. During suctioning with the 6 Fr catheter, proximal airway pressures were virtually unchanged; however, as ETT size decreased, distal airway pressures also decreased. The application of suction only modestly augmented the substantial decrement in measured tidal volumes when compared to catheter insertion alone. For the 8 Fr catheter, suction markedly reduced both proximal and distal airway pressures and tidal volumes. We conclude that the use of the CTSS tested in this neonatal ventilator/test lung model does not preserve continuity of volume or pressure delivery during suction procedures; therefore these cannot be the sole explanation for the reported reduction in suction related hypoxia. © 1992 Wiley‐Liss, Inc.
Spontaneous desaturations in intubated very low birth weight infants with acute and chronic lung disease
Authors: Durand Manuel , McEvoy Cindy , MacDonald Kelvin
Published: March 2007

Patients with chronic lung disease (CLD) have frequent episodes of spontaneous desaturations. Utilizing computerized pulse oximetry (CPO) we quantified the frequency and severity of spontaneous desaturations in very low birth weight (VLBW) infants with CLD. Thirty‐four studies by CPO were performed in intubated infants for 4 hours; 17 patients (birth weight, 550–980 g; postnatal age 28–85 days) had CLD, and 17 (birth weight, 520–980 g; postnatal age, 1–7 days) had acute lung disease. Oxygen saturation (Sa) was measured with the Nellcor N‐200 oximeter, its serial output (updated once a second) captured by a computer. Pulse rate, pulse amplitude, and heart rate were also monitored continuously. We measured respiratory system mechanics in 23 patients. Tidal volume (VT), respiratory system compliance (Crs), and resistance (Rrs) were obtained by the PeDS system. Spontaneous desaturation to Sa < 90% occurred for 4.5% of the time in acute patients vs. 27.1% of the time in chronic patients (P < 0.0001); to Sa < 85%, 0.7% vs. 7.6% of the time in acute vs. chronic patients (P < 0.002); and to Sa < 80%, 0.4% vs. 2.6% of the time in acute vs. CLD patients (P < 0.05). Rrs was significantly higher in the ventilated patients with CLD (174 cmH2O/L/s) than in the ventilated patients with acute lung disease (94 cmH2O/L/s, P < 0.0001). The mean Crs values of the two groups were comparable. Our preliminary data indicate that VLBW infants with CLD receiving assisted ventilation have a greater number of spontaneous desaturation episodes, as compared to patients with acute lung disease. © 1992 Wiley‐Liss, Inc.
Evaluation of the multiple linear regression method to monitor respiratory mechanics in ventilated neonates and young children
Authors: Rousselot J. M. , Peslin R. , Duvivier C.
Published: March 2007

A potentially useful method to monitor respiratory mechanics in artificially ventilated patients consists of analyzing the relationship between tracheal pressure (P), lung volume (V), and gas flow (\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm V}\limits^. $\end{document}) by multiple linear regression (MLR) using a suitable model. Contrary to other methods, it does not require any particular flow waveform and, therefore, may be used with any ventilator. This approach was evaluated in three neonates and seven young children admitted into an intensive care unit for respiratory disorders of various etiologies. P and V were measured and digitized at a sampling rate of 40 Hz for periods of 20–48 s. After correction of P for the non‐linear resistance of the endotracheal tube, the data were first analyzed with the usual linear monoalveolar model: P = PO + E.V + R.\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm V}\limits^. $ \end{document} where E and R are total respiratory elastance and resistance, and PO is the static recoil pressure at end‐expiration. A good fit of the model to the data was seen in five of ten children. PO, E, and R were reproducible within cycles, and consistent with the patient's age and condition; the data obtained with two ventilatory modes were highly correlated. In the five instances in which the simple model did not fit the data well, they were reanalyzed with more sophisticated models allowing for mechanical non‐homogeneity or for non‐linearity of R or E. While several models substantially improved the fit, physiologically meaningful results were only obtained when R was allowed to change with lung volume. We conclude that the MLR method is adequate to monitor respiratory mechanics, even when the usual model is inadequate. © 1992 Wiley‐Liss, Inc.
Delivery of micronized budesonide suspension by metered dose inhaler and jet nebulizer into a neonatal ventilator circuit
Authors: Arnon S. , Grigg J. , Nikander K. , Silverman M.
Published: March 2007

We compared the delivery of a micronized suspension of budesonide by a metered dose inhaler (MDI) with two different spacers (Aerochamber and Aerovent) and by two jet nebulizers (MAD2 and Ultravent) to a ventilated neonatal test‐lung using a standard neonatal ventilator circuit. The combination of MDI and Aerochamber was significantly better at delivering budesonide to a filter in front of the test lung (14.2% of aerosolized dose) than were either the MDI and Aerovent (3.6%) or the Ultravent or MAD2 jet nebulizers (0.02% and 0.68% of initial reservoir dose). Of the droplets emerging from the MDI, Aerochamber, and ET tube, 18% of the initial dose was in droplets < 4.7 μm. Assuming that the test‐lung model accurately reflects in vivo deposition, the combination of MDI and Aerochamber appears to be an extremely effective way of delivering budesonide aerosol to ventilated newborn infants. © 1992 Wiley‐Liss, Inc.
Effect of rapid thoracic compression on the cerebral blood flow‐velocity patterns of small infants
Authors: Maynard Roy , Mammel Mark C. , Holloman Keith K. , Porter Sharon , Boros Stephen J.
Published: March 2007

We measured the middle cerebral artery (MCA) flow‐velocities of 12 small infants (mean weight, 2,882 ± 602 g) before, during, and after the rapid thoracic compression (RTC) maneuvers of partial forced expiratory flow‐volume studies. Cerebral flow‐velocities were measured using transcranial Doppler ultrasonography. RTC increased MCA end diastolic flow‐velocities and Pourcelot indices of all infants (P < 0.001). These values returned to baseline immediately after the release of chest compression. We also measured the MCA flow‐velocities of several preterm infants during their normal daily activities. The changes in flow‐velocity patterns observed during normal daily life were similar to those observed during RTC. These findings demonstrate that RTC produces real, but likely not pathologic, changes in cerebral blood flow‐velocities. © 1992 Wiley‐Liss, Inc.
Comparison of 2‐channel and 4‐channel pneumograms
Authors: Abdulhamid Ibrahim , Vauthy Pierre A. , Barnett Bruce A. , Hufford David R. , Reddy Ram P. , Hunt Carl E.
Published: March 2007

To determine whether the addition of air flow and O2 saturation (Sa) channels improves sensitivity of the pneumogram in identifying cardiorespiratory pattern abnormalities, 2‐and 4‐channel pneumograms (PG‐2 and PG‐4) were simultaneously recorded in 91 consecutive infants. Forty‐one infants (45%) had cardiorespiratory symptoms, and 50 were asymptomatic. Pneumograms were considered abnormal for any of the following: apnea ≧ 20 seconds, heart rate < 80 bpm for gt; 5 seconds in preterm and < 60 bpm in full‐term infants (bradycardia), shorter apnea with bradycardia or desaturation, periodic breathing gt; 7% of total sleep time in preterm and gt; 4% in full‐term infants, or Sa < 85% for gt; 5 seconds. Both recordings were normal in 72% of infants and abnormal in 24%. In only 4% were the PG‐4 abnormal when the PG‐2 were normal, in all instances due to minimum Sa levels of 77–84% for 5–19 seconds associated with central apnea of intermediate duration (three infants) or with mixed apnea. The difference in frequency of abnormal results between the PG‐2 and PG‐4 recordings was not statistically significant (X2). In conclusion, although PG‐4 do increase the scope of physiological information obtained in infants with cardiorespiratory events, this short‐term study does not establish whether this increase results in any long‐term benefits. Further, at least in this number and these types of at‐risk infants, PG‐4 do not improve the sensitivity of cardiorespiratory recordings for detecting abnormalities. © 1992 Wiley‐Liss, Inc.
Lung mechanics and gas exchange in ventilated preterm infants during treatment of hyaline membrane disease with multiple doses of artificial surfactant (Exosurf)
Authors: Pfenninger Jürg , Aebi Christoph , Bachrnann Denis , Wagner Bendicht Peter
Published: March 2007

Eight premature infants ventilated for hyaline membrane disease and enrolled in the OSIRIS surfactant trial were studied. Lung mechanics, gas exchange [Pa, arterial/alveolar P ratio (a/A ratio)], and ventilator settings were determined 20 minutes before and 20 minutes after the end of Exosurf instillation, and subsequently at 12‐24 hour intervals. Respiratory system compliance (Crs) and resistance (Rrs) were measured by means of the single breath occlusion method. After surfactant instillation there were no significant immediate changes in Pa (36 vs. 37 mmHg), a/A ratio (0.23 vs. 0.20), Crs (0.32 vs. 0.31 mL/cm H2O/kg), and Rrs (0.11 vs. 0.16 cm H2O/mL/s) (pooled data of 18 measurement pairs). During the clinical course, mean a/A ratio improved significantly each time from 0.17 (time 0) to 0.29 (time 12‐13 hours), to 0.39 (time 24‐36 hours) and to 0.60 (time 48‐61 hours), although mean airway pressure was reduced substantially. Mean Crs increased significantly from 0.28 mL/cm H2O/kg (time 0) to 0.38 (time 12‐13 hours), to 0.37 (time 24‐38 hours), and to 0.52 (time 48‐61 hours), whereas mean Rrs increased from 0.10 cm H,O/mL/s (time 0) to 0.11 (time 12‐13 hours), to 0.13 (time 24‐36 hours) and to (time 48‐61 hours) with no overall significance. A highly significant correlation was found between Crs and a/A ratio (r=0.698, P < 0.001). We conclude that Exosurf does not induce immediate changes in oxygenation as does the instillation of (modified) natural surfactant preparations. However, after 12 and 24 hours of treatment oxygenation and Crs improve significantly. In contrast to other reports on dynamic compliance and gas exchange, we have been able to demonstrate an excellent correlation between oxygenation and Crs, determined by the single breath occlusion method. © 1992 Wiley‐Liss, Inc.
A prospective trial using salivary‐theophylline levels to guide asthma therapy
Authors: Virchow Johann‐Christian , Mansfeld Jochen , Matthys Heinrich , Virchow Christian
Published: March 2007

In three prospectively designed studies, first saliva (SA) samples were collected simultaneously with serum (SE) from 86 children who received slow‐release theophylline (Th) bid. for treatment of bronchial asthma. SA was collected with a standardized sampling procedure. Regression analysis revealed a close correlation between SE and SA–Th levels (r=0.959; SE=1.87 × SA + 0.05) and yielded a “therapeutic SA–Th range” of 5.8 to 10.7 mg/L. In 16 children the diurnal variation was then assessed by measuring 6 SA–Th levels within 24 hr, using the same sampling method. At 0, 9, and 24 hr SE–Th levels were also measured. The levels of SE–Th and SA–Th were again closely correlated (0.914 ≤ r ≤ 0.949) and both remained constant over the 24‐hr period. In the third prospective trial only SA levels were used to monitor Th therapy in 50 asthmatic children. Seven days after starting therapy SA‐Th levels were measured and then the Th dose was increased weekly until SA‐Th levels above 5.8 mg/L were reached. The following day SE and SA samples were collected simultaneously and their Th levels compared. In 36 of the 47 children who completed the study therapeutic SE‐Th levels (≥10 and ≤20 mg/L) were measured; in one patient it was 320 mg/L, in 6 it was between 8.0 and 10 mg/L, and only 4 had SE levels <8.0 mg/L. There were no potentially toxic SE‐Th levels that were not reflected by increased SA levels. From these prospective studies we conclude that SA‐Th levels can be used to guide Th therapy in children with asthma. © 1992 Wiley‐Liss, Inc.
Chronic graft‐versus‐host disease and pulmonary function
Authors: Kaplan Ellen B. , Wodell Ruthven A. , Wilmott Robert W. , Leifer Betty , Lesser Martin L. , August Charles S.
Published: March 2007

Pulmonary complications are a major cause of morbidity and mortality in bone marrow transplant recipients. Earlier series, consisting mainly of adults, have shown evidence of obstructive changes of pulmonary functions in association with chronic graft‐versus‐host disease (CGVHD). We longitudinally evaluated spirometry in 46 patients who received bone marrow transplants as children or as young adults to determine whether they had similar abnormalities. Group mean FEV1/FVC, and percent predicted FVC, FEV1, and FEF25‐75 values did not demonstrate obstructive changes in association with CGVHD in this patient population. Our findings suggest that younger patients with CGVHD, as a group, may fare better than older bone marrow transplant recipients with CGVHD. However, due to small sample sizes, it cannot be conclusively stated that the pulmonary function parameters analyzed do not differ in the two patient groups. © 1992 Wiley‐Liss, Inc.
Facemasks versus mouthpieces for aerosol treatment of asthmatic children
Authors: Lowenthal Diana , Kattan Meyer
Published: March 2007

Mouthpieces and facemasks are being used with nebulizers for delivery of medication in acute asthma. To compare the effectivity of the two devices, 64 children age 6 to 19 years presenting to the hospital with acute asthma were enrolled in a randomized, single‐blind study. Group 1 used a facemask. Group 2 used a mouthpiece connected to the nebulizer via short T‐shaped tubing. Clinical evaluation and spirometry were performed at baseline and 20, 40, and 60 minutes after a single treatment with albuterol. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and forced expiratory flow over the middle 50% of FVC (FEF25‐75) were determined at each point. Adverse effects were recorded. There was no significant difference in improvement between the groups. Patients with nasal congestion, age below 10 years, or severe airway obstruction did equally well with each method. Patients in the facemask group had a higher incidence of tremor. We conclude that the mouthpiece is an effective as the facemask and produces less tremor. © 1992 Wiley‐Liss, Inc.
Cilia in children with recurrent upper respiratory tract infections: Ultrastructural observations
Authors: Giorgi Pier Luigi , Oggiano Nicola , Braga Pier Carlo , Catassi Carlo , Gabrielli Orazio , Coppa Giovanni Valentino , Kantar Ahmad
Published: March 2007

We investigated the ultrastructure of nasal cilia in 27 children suffering from recurrent infections of the upper respiratory tract, during and after the onset of an acute respiratory infection, and after a convalescent period of 12 weeks. Our results demonstrated that in seven subjects after resolution of infection, the morphology of a large proportion of the cilia (32%) was not back to normal. These findings suggest a long‐term residual effect of infection, or the inability to reestablish normal ciliary structure during the convalescent period in some subjects with recurrent upper respiratory tract infection. © 1992 Wiley‐Liss, Inc.
Response to external obstruction in preterm infants with apnea
Authors: Upton C. J. , Milner A. D. , Stokes G. M.
Published: March 2007

A proportion of preterm infants respond to an external airway obstruction by becoming apneic. We have studied 23 infants (median birthweight, 1.14 kg; gestation, 29 weeks) on 80 occasions, to determine the time course of the response and its relationship with spontaneous apnea occurrence. Upper airway flow was measured with a face mask and pneumotachograph, and a tap was turned intermittently to produce an occlusion.

A total of 380 occlusions were analyzed. The infants became apneic during the obstruction on 72 occasions (19%), and after the obstruction on 122 occasions (32%). Both of these events were significantly more common than immediately prior lo the obstruction, when apnea occurred on 29 occasions (8%). Of the apneas following occlusion 57% were central in type. The point in the respiratory cycle at which obstruction occurred had no effect on the production of apnea. An obstruction score was calculated for each study. This was the mean of the number of apneas during and after each obstruction, expressed as a percentage of the number of obstructions per study. This score was positively correlated with the number of spontaneous apneas recorded. Obstruction score rose from a mean of 20% during days 0–14, to 34% during days 15–28, and thereafter it declined. This pattern may be relevant to the time course of apnea in susceptible infants. © 1992 Wiley‐Liss, Inc.
The relationship of RSV‐specific immunoglobulin E antibody responses in infancy, recurrent wheezing, and pulmonary function at age 7–8 years.
Authors: Welliver Robert C. , Duffy Linda
Published: March 2007

In order to determine if respiratory syncytial virus (RSV)‐specific IgE responses at the time of bronchiolitis in infancy are related to recurrent wheezing and pulmonary function at 7–8 years of age, a cohort of 43 infants was identified at the time of their initial RSV bronchiolitis episode. RSV‐specific IgE responses in nasopharyngeal secretions were determined, and patients were then followed prospectively with notation of the number of wheezing episodes and exposure to cigarette smoke at home. At 7–8 years of age the patients underwent skin testing to 7 environmental allergens and pulmonary function testing, including pulse oximetry and methacholine challenge. Pulmonary function following inhalation of bronchodilating agents was compared to baseline pulmonary function results in order to determine if abnormalities of pulmonary function were reversible. Recurrent wheezing following bronchiolitis was associated with the initial RSV‐IgE response, as well as with a family history of asthma. Current wheezing at age 7–8 years was associated with 2 or more positive skin tests (P < 0.01), a history of exercise‐induced wheezing (P = 0.01). and increased sensitivity to methacholine (P < 0.01). Pulmonary function test results were similar for groups with and without recurrent wheezing following bronchiolitis. For the entire study group, RSV‐IgE specific responses were unrelated to pulmonary function, but small airway dysfunction was associated with passive smoking (P < 0.025), and both large airway dysfunction and increased airway reactivity were associated with the number of positive skin tests (P < 0.025). Reduced small airway function improved following bronchodilator inhalation. The degree of improvement was inversely related to the degree of baseline dysfunction (P < 0.01), and was correlated with passive smoking (P < 0.01). These findings suggest that decreased pulmonary function following bronchiolitis is related to atopy and passive cigarette smoke exposure and may be reversible. © 1993 Wiley‐Liss, Inc.
Ontogeny of epithelial modulation of airway smooth muscle function in the guinea pig
Authors: Southgate W. Michael , Pichoff Bruce E. , Stevens Edward L. , Balaraman Venkataraman , Uyehara Catherine F. T. , Nakamura Kenneth T.
Published: March 2007

The purpose of this study was to investigate the ontogeny of guinea pig airway smooth muscle (ASM) responses and the epithelial modulation of these responses. Paired tracheal rings from fetal, newborn, and adult guinea pigs were studied. One of each pair was denuded of airway epithelium (AE) by gentle rubbing. Isometric tension was measured in rings mounted in organ baths filled with ‘Krebs’ solution. Cumulative dose‐response curves were generated by adding either acetylcholine (ACh) or histamine over a concentration range of 1 0−8−10−4 M. Significant agent‐specific, age‐related differences in maximal contraction were seen for both ACh and histamine in intact tissues (Ach: for fetus 66.7 ± 6.2 × 10−2 g/mg wet wt, for newborn 51.4 ± 6.2, for adult 29.3 ± 2.6; histamine: for fetus 46.1 ± 5.1, for newborn 72.9 ± 6.0, for adult 25.3 ± 3.2). Similar differences in sensitivity to both agents were observed (EC50 with ACh: for fetus 0.80 ± 0.11×10−6 M; for newborn 0.85 ± 0.26 × 10−6 M; for adult 1.7 ± 0.20 × 10−6M; EC50 with histamine: for fetus 1.88 ± 0.50 × 10−6 M; for newborn 1.34 ± 0.16 × 10−6M; for adult 3.78 ± 0.75 × 10−6 M). Removal of AE caused a significant decrease in maximal responses to ACh in fetal tissue, a smaller, insignificant one for newborn and a nonsignifcant alteration for adult tissues. Age‐related sensitivity difference was abolished with removal of AE to ACh but not to histamine. In conclusion, during development (1) maximum tension, expressed as force per tissue weight, when generated follows the pattern, fetus > newborn > adult with ACh and newborn > fetus > adult with histamine; (2) the EC50 pattern for both ACh and histamine was, fetus = newborn < adult; (3) for denuded tissue maximum tension by ACh was significantly decreased only in fetal trachea; and (4) removal of AE abolished the age‐dependent difference in sensitivity to ACh, but not to histamine. © 1993 Wiley‐Liss, Inc.
Nebulized steroid therapy in bronchopulmonary dysplasia
Authors: Cloutier Michelle M. , McLellan Nancy
Published: March 2007

The effect of inhaled beclomethasone dipropionate (BEC) was studied in seven infants between 7 and 18 months of age with glucocorticoid‐dependent bronchopulmonary dysplasia. Oral glucocorticoid therapy, pulmonary function, growth, daily caloric consumption, blood pressure, blood sugar, blood gases, and immunoglobulins were monitored for 3 months before (control period) and 3 months after (intervention period) instituting inhaled beclomethasone dipropionate (25 μg/kg/day divided tid) delivered by Pulmoaide with a DeVilbiss nebulizer. Acute BEC inhalation produced no change in pulmonary function. During BEC treatment, oral glucocorticoid therapy was decreased in all infants, stopped in four infants within 3 months and in the other three infants in 4‐5 months. Within 1 month of inhaled BEC the rate of linear growth and weight increased markedly (2.2 ± 1.8 vs 6.4 ± 2.4 cm/month ‐ mean ± SD and 9.3 ± 6.5 vs 18.2 ± 7.4 g/day, respectively without change in average daily caloric consumption (113 ± 16 vs. 110 ± 15 cal/kg/day). Immunoglobulins also significantly increased during BEC therapy (Ig G(Total) 246 ± 74 vs 463 ± 111 mg/dL). Pulmonary function revealed moderate obstructive pulmonary disease before BEC. After 3 months of BEC inhalation no significant change occurred although respiratory system resistance decreased and the flow at 25% of tidal volume to peak flow ratio increased more than predicted by intersession variability. In no infant did pulmonary function decline after BEC, nor were any apparent adverse effects noted in this small group of patients. In conclusion, inhaled BEC was effective in decreasing oral glucocorticoid therapy and in modifying glucocorticoid‐induced growth suppression in a very small, highly select group of infants with bronchopulmonary dysplasia. © 1993 Wiley‐Liss, Inc.
Episodes of spontaneous desaturations in infants with chronic lung disease at two different levels of oxygenation
Authors: McEvoy Cindy , Durand Manuel , Hewlett Valerie
Published: March 2007

The optimal range of pulse oximeter oxygen saturation (Sao2) for infants with chronic lung disease (CLD) has not been well established. We quantified episodes of spontaneous desaturation, at two different ranges of Sao2. For 1 hr each, we alternatively administered inspired O2 concentrations (Fio2, necessary to maintain an Sag of 94–96% or 87–91% to 21 patients (mean birth weight, 865 g; gestational age, 27.3 weeks; postnatal age 40.6 days) with CLD (defined by Fio2 > 0.21 at ≥ days and radiographic evidence). Sao2 was monitored with the Nellcor N‐200 oximeter and analyzed by a computer program (SatMaster). The percentage of time the infants desaturated to levels of Sao2 <85 and <80% revealed significantly fewer spontaneous episodes during the hour of higher baseline Sao2 (P < 0.0002). Comparison of episodes of spontaneous desaturation to Sao2 < 80 and <85%, lasting 0–15, 16–30, 31–45 sec also showed significant differences between the two levels of Sao2.

We conclude that when Infants with CLD are maintained at a higher Sao2 they probably experience fewer episodes of spontaneous desaturations, because of less alveolar hypoxia. We bell that attempts at weaning the Fio2 should be tempered with the need of maintaining an adequate Sao2. Therefore, prolonged monitoring of oxygenation in infants with CLD at different levels of Sao2 could be helpful during the weaning process. Pediatr Pulmonol. © 1993 Wiley‐Liss, Inc.
A lamb model for human respiratory syncytial virus infection.
Authors: Lapin Craig D. , Hiatt Peter W. , Langston Claire , Mason Edward , Piedra Pedro T.
Published: March 2007

Respiratory syncytial virus (RSV) is the most important cause of bronchiolitis and pneumonia in young children. The development of an animal model of RSV disease serves to better understanding the pathophysiology of airway disease from RSV infection in infants and children. Groups of six lambs were inoculated intratracheally (IT) or intranasally (IN) with a human strain of RSV (H‐RSV). For controls 8 lambs received IT virus‐free cell lysate. Tachypnea and fever were observed significantly more often following IT than following IN inoculation of H‐RSV or IT placebo (for tachypnea: 20 of 69 days, 5 of 63 days, and 3 of 89 days, respectively, P < 0.001; for fever: 6 of 69 days, 0 of 63 days, and 1 of 89 days, respectively, P < 0.02). Nasal fluid production was significantly more frequent in both IT (14 of 69 days) and IN (15 of 63 days) groups than in the placebo group (2 of 87 days, P < 0.001). Postvaccination geometric mean titers (GMT, arithmetic transformation of log 2) of RSV‐specific neutralizing antibody were significantly increased in the IT H‐RSV group compared with postplacebo GMTs at 1 week (72 vs. 6.7, P < 0.03). By the second week postinoculation both H‐RSV‐infected groups had comparable levels of RSV‐specific neutralizing antibody titers and had significantly greater GMTs for the second through to the fourth week than the placebo group (144, 128, and 4.8, respectively P < 0.0008). Bacterial isolates of the upper airway were comparable among the three groups. Histopathology at day 28 postinoculation was unremarkable for the three study groups. The development of overt clinical illness in lambs inoculated with H‐RSV suggests that the H‐RSV lamb model may be used to delineate the pathogenesis of lung injury of H‐RSV infection. © 1993 Wiley‐Liss, Inc.
Developmental control of collagen gene expression in the rat lung: Confirmation of early observations of lung growth
Authors: Larson Janet E.
Published: March 2007

The short gestation period of the rat allows one to see rapid morphologic and biochemical changes in the lung. It has been shown that the rat lung undergoes a period of distension over the first several days of life followed by a rapid alveolar growth. Total lung collagen also increases during this time period. We have examined the changes in types I and III procollagen transcrpts during the perinatal period and have compared them to the above observations. Total RNA was extracted from the lungs of offspring of time‐pregnant Sprague‐Dawley rats after large airways were removed. Northern hybridization was performed to determine the quality of steady‐state RNA and rule out cross‐hybridization while densitometric tracings of slot‐blot hybridizations allowed comparative estimates of the target sequence of RNA. Immediately following birth, the steady‐state rnRNA procollagen levels increased and a shift to a predominant type I production occurred. These changes preceded the rapid increase of collagen content and alveolarization known to occur at three days of age. These data provide further evidence that collagen production is controlled at the level of transcription and in temporal and tissue‐specific manners. © 1993 Wiley‐Liss, Inc.
Nonbronchoscopic bronchoalveolar lavage in mechanically ventilated infants: Technique, efficacy, and applications
Authors: Koumbourlis Anastassios C. , Kurland Geoffrey
Published: March 2007

Bronchoalveolar lavage with the fiberoptic bronchoscope is commonly used for the diagnosis of pulmonary infections in mechanically ventilated adults and children. However, its use for intubated infants is precluded because the small artificial airway does not permit the passage of the bronchoscope. We have developed a technique for nonbronchoscopic bronchoalveolar lavage, performed via a sterile, disposable feeding tube. We have used this technique in 15 infants with diffuse interstitial disease and/or atelectasis, while they were intubated and mechanically ventilated. The volume of the lavage effluent averaged 70.3% of the volume instilled. Specific diagnosis on the basis of the cytologic evaluation and/or culture of the lavage fluid was possible in 9 (SOYO) patients. Two patients with atelectasis showed radiographic evidence of improvement following the procedure. There were no complications. We conclude that nonbronchoscopic bronchoalveolar lavage is well tolerated, and clinically useful in small, mechanically ventilated infants with respiratory failure due to diffuse pulmonary disease. This technique provides a lower risk alternative to more invasive, and costly procedures. © 1993 Wiley‐Liss, Inc.
What limits endurance in normal children?
Authors: Bogaard Jan M. , Bijl Annemarie , van Dongen Arthur R. , Kerrebijn Karel F. , de Jongste Johan C.
Published: March 2007

We have compared the results of a standard progressive maximal exercise test to those of an endurance exercise test in 22 healthy school children (13 girls, 9 boys, mean age 14.8 years) in order to examine whether it is possible to extrapolate results from a maximal test to predict their endurance capacity. All children performed a standard progressive maximal exercise test (15 W increments every minute until exhaustion) and an endurance test (individually calculated loads to mimic cycling at 20 km/h against a windforce 5 of Beaufort for 30 minutes) on 2 separate days. In both tests metabolic [oxygen uptake (Vo2), CO2 production, blood lactate accumulation], ventilatory [minute ventilation (VE)], and circulatory variables were measured. From the maximal test the threshold of lactate accumulation (LT) was determined. Thirteen children were capable of enduring the 30 minute exercise (Group l), and 9 could not complete the endurance test (Group 2). These two groups were comparable with respect to age, height, and baseline lung function. Children in Group 2 had a higher mean weight (P < 0.005) than those in Group 1. Eight of the 9 children in Group 2 were girls, whereas Group 1 consisted of 5 girls and 8 boys. There was no significant difference between Group 1 and 2 in the mean values of Vo2 max, maximal respiratory exchange ratio (R max), VEmax, LT, oxygen pulse, and other variables obtained during the maximal exercise tests. Lactate accumulation during the endurance test in Group 2 was larger than in Group 1 (P < 0.005). This confirms that lactate metabolism is a key factor that determines endurance capacity. The endurance time also correlated significantly (P < 0.01) with the ratio between VE and maximal voluntary ventilation (MVV). We conclude that exercise endurance in healthy children correlates with variables related to lactate metabolism. It appears that a load at or lower than the LT can be sustained for 30 minutes in the great majority of healthy children. © 1993 Wiley‐Liss, Inc.
Spirometry in the asthmatic child: Is FEF25–75 a more sensitive test than FEV1/FVC?
Authors: Lebecque P. , Kiakulanda P. , Coates A. L.
Published: March 2007

The use of spirometry in the assessment of children with asthma is taking on new importance with the realization that considerable airway obstruction may exist in the absence of clinically detectable abnormalities. There has been controversy over the value and relative sensitivity of various spirometric indices. This study evaluated the forced expiratory flow between 25% and 75% of vital capacity (FEF25–27), forced expired volume in 1 second (FEV1 ), and the ratio between the FEV1 and the forced vital capacity (FVC) in 100 asthmatic children aged 6–17 years, 29 of whom were wheezing at the time of the evaluation. All children with clinical wheezing had a FEV25–27 <2 standard deviations (SD) below the mean (–2 SD), whereas 8 had a normal FEV1. The majority of the wheezing children had abnormalities of all 3 indices, whether expressed as ⩽ −2 SD or, in the case of the FEV1/FVC, arbitrarily taken as <80%. Sixty‐seven children of the entire study group had at east 1 abnormal spirometric index, but 38 of these had no clinical abnormalities. Twelve children had a reduced FEF25–27 as the only abnormality. These results suggest that FEF25–27 is a sensitive index of airway obstruction. Pediatr Pulmonol. 1993; 16: 19‐22. © 1993 Wiley‐Liss, Inc.
Dexamethasone treatment suppresses collagen synthesis in infants with bronchopulmonary dysplasia
Authors: Co Edward , Chari Gopal , McCulloch Kristine , Vidyasagar Dharmapuri
Published: March 2007

Collagen is an essential component of connective tissue and is present in the pulmonary interstitium. Collagen deposition is known to increase in many acquired chronic diseases, including bronchopulmonary dysplasia (BPD). Urinary excretion of hydroxyproline has been used as a specific index of collagen synthesis. Many studies have demonstrated that dexamethasone therapy is associated with respiratory improvement in infants with BDP but the mechanism of this effect is not well understood. We postulated that in infants with BDP who receive dexamethasone, suppression of collagen synthesis may cause respiratory improvement. Therefore, we studied the effect of dexamethasone on respiratory status and urinary excretion of hydroxyproline in 14 ventilator‐dependent infants with BDP. Infants received 0.5 mg/kg/day dexamethasone, tapered by half every 3 days to complete a 12 day course. Eleven of the 14 infants were extubated at a mean ± SD of 8.7 ± 4.9 days after starting dexamethasone. Mean urinary hydroxyproline/creatinine ratios at 3, 6, 9, and 12 days of dexamethasone therapy were significantly lower than the mean pretreatment value, but after discontinuation rapidly rose toward baseline values. Decreased urinary excretion of hydroxyproline indicates that dexamethasone suppressed collagen synthesis in these infants. We speculate that suppression of collagen synthesis reduced pulmonary inflammation and fibrosis, resulting in respiratory improvement. Pediatr Pulmonol. 1993; 16:36–40. © 1993 Wiley‐Liss, Inc.
Association between pulmonary and gastric inflammatory cells on the first day of life in preterm infants
Authors: Arnon Shmuel , Grigg Jonathan , Silverman Michael
Published: March 2007

It has been shown that inflammatory cells in the newborn lung are fetal in origin, whereas those in the amniotic fluid are maternal. In order to explore the relationship between fetal amnionitis and neonatal pneumonitis, we collected paired samples of gastric aspirate within 2 hours of birth, and bronchoalveolar lavage fluid within 24 hours of birth from intubated preterm infants. Leukocyte counts in bronchoalveolar lavage fluid correlated with the duration of membrane rupture (r = 0.68, P = 0.0001). There was a high degree of correlation between leukocyte counts in the two fluids (r = 0.86, P = 0.0001). The factors responsible for this association are unknown. Pediatr Pulmonol. 1993; 16:59–61. © 1993 Wiley‐Liss, Inc.
Unusual form of endobronchial aspergillosis in a patient with cystic fibrosis
Authors: Sammut Paul H. , Howard Susan T. , Linder James , Colombo John L.
Published: March 2007

The isolation of Aspergillus fumigatus from airway secretions from patients with cystic fibrosis (CF) is common and usually denotes asymptomatic colonization or allergic broncho‐pulmonary aspergillosis (ABPA). A 12‐year‐old boy with CF acutely developed moderately severe symptoms of unremitting cough, fever, dyspnea, weight loss, and cyanosis. Chest radiographs demonstrated widespread unilateral infiltrates and volume loss. By bronchoscopy tenacious mucous plugs were seen occluding the left lower lobe bronchus. Cultures from sputum and sequential bronchoalveolar lavage grew Aspergillus fumigatus, but other significant criteria for diagnosing APBA were lacking. No improvement was seen with a 3 week course of systemic corticosteroid and antibiotic therapy. Treatment with amphotericin B and short‐term mechanical ventilation resulted in rapid resolution of all symptoms. This form of endobronchial aspergillosis has not been described previously. Pediatr Pulmonol. 1993; 16:69–73. © 1993 Wiley‐Liss, Inc.
Chronic modifications of lung and heart development in glucocorticoid‐treated newborn rats exposed to hyperoxia or room air
Authors: Thibeault D. W. , Heimes B. , Rezaiekhaligh M. , Mabry S.
Published: March 2007

We assessed the mechanics and morphology of the lung in 165 rats treated neonatally with either room air (RA), O2, RA + steroids, or O2, + steroids. Newborn Sprague‐Dawley male rats were randomly assigned to these groups. O2,‐exposure (0.96‐1.0 FiO2 lasted 5 days, and dexamethasone treatment consisted of eight daily S.C. injections of drug or buffer in successive doses of 0.5,0.4.0.3,0.2,0.1, 0.1. 0.1. and 0.1 mg/kg. At 58 days, right ventricular systolic pressure (RVP) was measured. At 60 days, all rats were sacrificed for obtaining lung weight and DNA, saline pressure‐volume (P‐V) curves, and morphometry. We weighed right ventricles (RV) and left ventricles + septa (LV). Hyperoxia alone did not, but steroid decreased survival rate to 79.4% (95.3% in RA rats, P < 0.02). Only 21 of 40 (52%) O2 + steroids rats survived, less than in both RA groups (P < 0.001). RV weight, RVP and muscularization of alveolar duct arteries were significantly increased in O2 vs. RA rats. In RA + steroids rats, weight of the LV was decreased but RV, RVP, and lung vasculature were not affected. These effects were additive in the O2 + steroid group. Wet lung weights and DNA were increased for RA + steroid rats over all others. O2 and steroids shifted the P‐V curve to the left and O2+ steroids still further. Maximal lung volume increased significantly with RA + steroids and still further in O2 + steroids but not in O2 alone. O2 and steroids significantly increased the mean linear intercept and O2 + steroids even more so. In O2‐ and steroid‐treated rats, the parenchymal air space increased. In conclusion, both neonatal hyperoxia and steroid administration caused aberrations in the growth of lung and connective tissue. The effects of the two were additive. The vascular system, maximal lung volume, and DNA responded differently, presumably by different modes of action. Pediatr Pulmonol. 1993; 16:81–88. © 1993 Wiley‐Liss, Inc.
Predictive value of pulmonary function testing during pulmonary exacerbations in cystic fibrosis
Authors: Rosenberg Samuel M. , Schramm Craig M.
Published: March 2007

The optimal duration of therapy for acute exacerbations of cystic fibrosis (CF) has not been defined, and the utility of serial pulmonary function testing in predicting the duration of therapy has yet to be established. In a review of 90 pulmonary exacerbations of 39 patients with CF requiring hospitalization, we found that 72% of the patients recovered following 2 weeks of intravenous antibiotics and aggressive chest physiotherapy, and that 28% required an extended third week of therapy. Recovery was delayed in patients with more severe chronic pulmonary disease, but the rate of improvement was independent of the degree of pulmonary deterioration with the acute exacerbation. A 40% recovery of FEV, at 1 week was found to correlate significantly with the duration of hospitalization in the 90 patients. When prospectively applied to a second series of consecutively hospitalized patients with CF, 25/28 patients admitted for 2 weeks demonstrated > 40% improvement in FEV, at 1 week, as compared to 5/10 patients subsequently treated for ≤3 weeks (P = 0.030). The predictive values for 2‐ or 3‐week hospitalizations with 1‐week interval recovery of > 40% or > 40% in FEV, were 79% and 62%, respectively. These findings suggest that the response to intensive therapy in CF exacerbations is variable and that improvements in pulmonary function after 1 week of therapy may be used to predict the subsequent duration of therapy in the majority of CF patients with pulmonary exacerbations. Pediatr Pulmonol. 1993; 16:227–235. © 1993 Wiley‐Liss, Inc.
Bronchial responsiveness to inhaled metabisulfite in asthmatic children increases with age
Authors: Vandenbossche L. E. G. , Hop W. C. J. , de Jongste J. C.
Published: March 2007

Inhaled bisulfite (HSO3) aerosol produces bronchoconstriction in asthmatics but not in normals. This effect is probably due to local formation of SO2 which stimulates vagal afferents in the airway mucosa, and gives rise to bronchoconstriction that is partly due to a cholinergic reflex. Metabisulfite (MBS) produces bronchoconstriction in most adult asthmatics, but its effect in children has received little attention. The present study was done to assess MBS‐induced bronchoconstriction as a function of age in asthmatic children, and to compare MBS responsiveness with the response to inhaled metacholine (MCH), which is commonly used for bronchoprovocation testing. In 36 children with moderate asthma, selected to cover the age range between 3 and 20 years, we compared airway responsiveness to MBS and MCH, expressed as the provocative dose that causes a 20% fall in baseline forced expiratory volume in 1 sec (FEV1, PD20). We also measured the PD20 to MBS after pretreatment with the anticholinergic ipratropiumbromide, to estimate the noncholinergic component of the response. After bronchial provocation with MCH, a PD20 was reached in 32 children, and no significant relation of PD, to age was found. A PD20 [MBS] was seen in only 17 patients, and more frequently in older children. There was a significant negative correlation between age and PD20 [MBS]. Ipratropium pretreatment reduced the response to MBS in 14 of the 17 children who had a PD20 [MBS]. The PD20 [MBS] after ipratropium pretreatment was also significantly negatively related with age. This suggested that the increased prevalence of MBS responsiveness was due to an increase of the noncholinergic component of the response. We conclude that, in this cross‐sectional study, the sensitivity of asthmatic children to MBS‐induced bronchoconstriction increases with age, and that this is because of an increase of the noncholinergic component of the response to MBS. We speculate that this reflects an abnormal development of the autonomic control of airway caliber in children with asthma. Pediatr Pulmonol. 1993; 16:236–242. © 1993 Wiley‐Liss, Inc.
Measurement of breath amplitudes: Comparison of three noninvasive respiratory monitors to integrated pneumotachograph
Authors: Adams Jose A. , Zabaleta Ignacio A. , Stroh David , Sackner Marvin A.
Published: March 2007

Measurement of breath amplitude (BA) and similarly tidal volume (VT) in newborn infants is the standard for detection of apnea and hypopneas. The purpose of our study was to compare the accuracy for BA by three frequently utilized noninvasive respiratory monitors: respiratory inductive plethysmography (RIP), mercury in silastic strain gauges (SG), and impedance pneumography (IP). Twenty healthy full‐term infants were studied in both supine and prone postures. The RC and AB gain factors for RIP were obtained using qualitative diagnostic calibration (QDC) procedure. The electrical gain of IP was set equivalent to the BA signal of a pneumotachograph (PNT). The three devices were calibrated in the supine posture and measurements were repeated in the prone posture without changing their calibration factors. Compared to PNT, postural change did not significantly alter BA measured by RIP. The accuracy of breath‐to‐breath BA measurement in the prone posture was worse for IP and SG compared to RIP and PNT. In contrast to SG or IP, the accuracy of BA measurement maintained was by RIP after a postural change from supine to prone in fullterm newborns. Pediatr Pulmonol. 1993; 16:254–258. © 1993 Wiley‐Liss, Inc.
Familial congenital bronchiectasis: Williams‐Campbell syndrome
Authors: Jones V. Faye , Eid Nemr S. , Franco Sofia M. , Badgett J. Thomas , Buchino John J.
Published: March 2007

Williams–Campbell syndrome was first described in 1960 as a rare form of bronchiectasis. Its pathogenesis is characterized by the absence or markedly diminished cartilage around the bronchi. Although the familial nature was postulated early on, only one possible familial Occurrence has been reported in the literature. We present two family members in whom respiratory symptoms developed within the first year of life and were found to have histopathologic changes consistent with Williams–Campbell syndrome. This would lend further support of a developmental origin for this type of bronchiectasis. Pediatr Pulmonol. 1993; 16:263–267. © 1993 Wiley‐Liss, Inc.
Parental childhood respiratory illness and respiratory illness in their infants
Authors: Camilli Anthony E. , Holberg Catharine J. , Wright Anne L. , Taussig Lynn M. ,   Group Health Medical Associates
Published: March 2007

Parental histories of childhood respiratory trouble (CRT) were examined as risk factors for lower respiratory tract illnesses in healthy infants enrolled in the Children's Respiratory Study, Tucson, Arizona. A parental history of childhood respiratory trouble before age 16 was a risk factor for infantile lower respiratory tract illnesses (LRIs). Early age of onset of the parental CRT and those illnesses described as asthma or bronchiolitis showed the greatest risk: odds ratio = 2.8, P < 0.05. After controlling for known and suspected confounders, a parental history of CRT described as asthma or bronchiolitis with onset before age 3 was associated with wheezing LRls in their children, with an odds ratio of 2.6, P < 0.05. A parental history of CRT described as bronchitis/croup was associated with nonwheezing LRls in their children: odds ratio = 2.2, P < 0.05. These findings suggest a familial component to childhood respiratory trouble which may have a hereditary basis. Pediatr Pulmonol. 1993; 16:275–280. © 1993 Wiley‐Liss, Inc.