bluuebunny/crossref_metadata_2025 huggingface dataset:
Sequential pulmonary function measurements in very low‐birth weight infants during the first week of life
Authors: Anday Endla K. , Godart‐Wlodavar Anne , Delivoria‐Papadopoulos Maria
Published: March 2007

Sequential lung function was measured in 12 very low‐birth weight infants (≤ 1,250 g) within 14 hours of birth, and at daily intervals thereafter for the first week of life, using an esophageal balloon and pneumotachograph system. All infants were clinicaly free of respiratory distress syndrome and radiographically showed no evidence of atelectasis or pulmonary edema. The alveolar‐arterial oxygen tension gradient was high at birth and remained elevated over the period during which arterial blood gases were monitored. Increases of lung compliance and tidal volume between the first day and the end of the first week of life were not significant. Day‐to‐day determinations of lung compliance revealed an individual and group variability without a definite pattern. Lung resistance measurements indicated no clear trend for the group as a whole, but inspiratory resistance was generally lower than expiratory resistance.

Possible causes, in addition to technical factors, that may account for the variability in the pulmonary mechanics of these small infants include an instability of lung volume and uneven distribution of pleural pressure due to chest wall distortion, differences in sleep‐state, and alteration in the distribution of body fluids, resulting in a change in lung water. Any or all of these mechanisms may result in an unstable lung, even in an apparently clinically stable very low‐birth weight infant.
Stimulus parameters for phrenic nerve pacing in infants and children
Authors: Brouillette Robert T. , Ilbawi Michel N. , Klemka‐Walden Linda , Hunt Carl E.
Published: March 2007

Phrenic nerve pacing has been used since 1966 to support breathing in quadriplegics and patients with central hypoventilation syndrome (CHS). Recently, using low‐frequency, long‐inspiratory‐time (Ti) stimulation, phrenic nerve pacing has been used successfully to support breathing 24 hours per day in adults and older children. However, no similar experience exists for infants and young children. Therefore, in 27 studies in 14 infants and children we determined the effects of changing Ti and interpulse interval (the inverse of stimulus frequency) on ventilation. Diaphragmatic action potentials, airflow, tidal volume, PACO2 and SaO2 were measured during sleep. Phrenic nerve pacing proved useful in 13 of 14 patients to support breathing either during wakefulness (n = 7) or during sleep (n = 6). We found that adequate ventilation could be achieved at significantly longer interpulse intervals, 95 ± 25 (mean ± SD) ms, and shorter Ti, 580 ± 80 ms, than previously reported. At an average respiratory rate of 21 ± 8 breaths/min it was thus possible to maintain adequate ventilation despite a marked reduction in the number of phrenic nerve stimuli. Theoretically, these reductions in phrenic nerve stimulation should minimize the chance of pacing‐induced diaphragmatic damage. These results suggest that 24 hour per day phrenic nerve pacing may be a realistic goal in selected infants and children.
Relative contribution of ribcage and abdomen during augmented breaths in infants
Authors: Mathew Oommen P. , Pronske Maria L. , Clark Mark L.
Published: March 2007

Changes in the relative contribution of ribcage and abdomen during augmented breaths were assessed in two groups of infants (<2 weeks and 4–12 weeks old). In both groups ribcage and abdominal movements increased during augmented breaths in quiet sleep. In the older infants the relative increase was greater for the ribcage (P < 0.05) when expressed either as a ribcage to abdominal movement ratio or as a percent of the respective movements during control breaths. In contrast, no significant change of the relative contribution was observed in the younger age group. During active sleep paradoxical movement of the ribcage, observed during tidal breaths, continued during the first phase of the augmented breath; however, during the second phase of inspiration, the ribcage moved outward in all but one infant. Our results show that marked increases in tidal volume are associated with greater increases in ribcage contribution in infants beyond the neonatal period. This may reflect differences in recruitment patterns of intercostal muscles during development.
Incidence and implications of false‐negative sweat test reports in patients with cystic fibrosis
Authors: Legrys Vicky A. , Wood Robert E.
Published: March 2007

It is well known that false‐positive sweat tests occur commonly, but since a positive test should always be repeated, such an error is likely to be discovered. False‐negative results, however, are more difficult to detect and are generally assumed to be much less frequent than false‐positive results. Diagnostic delay caused by false‐negative reports may lead to substantial morbidity. Review of the medical records of 147 unselected patients with cystic fibrosis followed in our center revealed that 17 (12%) initially had one or more sweat tests that were falsely negative (or were so reported or interpreted). In seven patients, there was diagnostic delay with adverse clinical consequences. Many factors may contribute to the incidence of false‐negative sweat tests, and negative results must not be accepted as definitively excluding cystic fibrosis if the clinical syndrome is otherwise suggestive.
Comparison of piperacillin alone versus piperacillin plus tobramycin for treatment of respiratory infections in children with cystic fibrosis
Authors: McCarty James M. , Tilden Samuel J. , Black Phillip , Craft J. Carl , Blumer Jeffrey , Waring William , Halsey Neal A.
Published: March 2007

Seventeen patients with cystic fibrosis (CF) and pulmonary exacerbations were randomly assigned to two treatment groups: piperacillin 600 mg/kg/day (P), and piperacillin 600 mg/kg/day plus tobrarmycin (PT), in order to determine the safety and pharmacokinetics of high‐dose piperacillin and whether piperacillin alone was effective for the treatment of Pseudomonas infections. The mean half‐life of piperacillin was 0.54 hours, with a peak concentration of 232 μg/ml. No differences between P and PT groups were noted in clinical assessment, as judged by Shwachman scores, pulmonary function testing, or weight gain. However, during the course of treatment, quantitative sputum cultures decreased by greater than 102 colony‐forming units in only 5 out of 19 Pseudomonas isolates from the P group, compared with 12 of 19 isolates from the PT group (P < 0.03, Chi‐square). Although emergence of resistance was not seen, one isolate had an increase in minimum inhibitory concentration from 8 to 128 μg/ml. There were no serious adverse reactions to piperacillin; only one patient developed fever possibly related to piperacillin. Therapy with high‐dose piperacillin was safe in children with CF. Treatment with piperacillin alone was less effective than combination therapy with gentamicin for reduction in titer of Pseudomonas in sputum. However, the role of antimicrobial agents in the treatment of CF remains undefined. A double‐blind placebocontrolled trial is indicated.
Use of bronchoalveolar lavage in immunocompromised children with pneumonia
Authors: Pattishall Edward N. , Noyes Blakeslee E. , Orenstein David M.
Published: March 2007

Because pneumonia in the immunocompromised host presents a diagnostic dilemma to the pediatrician, we prospectively studied the use of bronchoalveolar lavage (BAL) with flexible fiberoptic bronchoscopy in 14 immunocompromised children with pneumonia over a 5‐month period. The children received immunosuppressive agents because of organ transplants, cancer, or systemic lupus erythematosus. A diagnosis was made by BAL in 10 (71%) of the 14 children. Pathogenic organisms included Pneumocystis carinii in six, cytomegalovirus (CMV) in two, Aspergillus fumigatus in one, and a mixed infection of Candida albicans and CMV in one. There were no complications. Because BAL by flexible fiber‐optic bronchoscopy is a rapid and safe procedure and a diagnosis can be made in a majority of cases, we recommend its use in immunocompromised children with pneumonia before resorting to lung biopsy.
Tracheomalacia and bronchomalacia associated with larsen syndrome
Authors: Rock Michael J. , Green Christopher G. , Pauli Richard M. , Peters Mary Ellen
Published: March 2007

Bronchomalacia has not previously been described in association with Larsen syndrome. In this article, three children with Larsen syndrome are reported. All three patients have tracheomalacia, and one of them has diffuse bronchomalacia diagnosed at flexible fiberoptic bronchoscopy. The patients' symptoms of airway obstruction include stridor, cyanosis, apnea, and recurrent pneumonias. Recognition of these abnormalities may allow the institution of supportive therapy.
Absence of long term pulmonary sequelae after mild meconium aspiration syndrome
Authors: Stevens John C. , Eigen Howard , Wysomierski David
Published: March 2007

To assess residual damage from meconium aspiration syndrome (MAS), we studied 12 children, ages 6 to 9 years, an average of 7.4 years after injury. Our sample consisted of mildly affected patients, only one having required intubation and mechanical ventilation in the acute phase of illness. In each child we measured FVC, FEV1, PEFR, MMEFR, VisoV, lung volumes by plethysmography, DLCO and calculated FEV1/FVC and RV/TLC. Methacholine bronchial challenge was performed and the PD20 was calculated. These results were compared with those obtained from a group of 12 normal children studied in our laboratory.

No significant difference was found for pulmonary function parameters studied, except for VisoV which was greater in MAS patients than normals (P < 0.02). Given the inherent high degree of variability with VisoV, we were not able to ascribe this isolated finding to be indicative of small airway disease in these asymptomatic patients. We conclude that patients with mild to moderate initial insult from MAS show an absence of pulmonary sequelae when tested at an average of 7.4 years of age.
Influence of smooth muscle tone and longitudinal tension on the collapsibility of immature airways
Authors: Penn Raymond B. , Wolfson Marla R. , Shaffer Thomas H.
Published: March 2007

Mechanical properties and pressure‐flow relationships of tracheae excised from very premature lambs were studied in a plethysmograph. Control (Group 1) data revealed the tracheae to be extremely compliant, collapsible airways, with an inflation compliance (Si) of 0.033 (±0.004 SE) mmHg−1, collapsing compliance (Sc) of 0.026 (± 0.001 SE) mmHg−1, and pressure‐flow relationships similar to those of a Starling resistor. Acetylcholine administration (Group II) lowered both Si, 0.026 (± 0.003 SE) mmHg−1 and Sc, 0.022 (± 0.003 SE) mmHg−1, asdid longitudinal stretch (Group III): Si, 0.021 (±.003 SE) mmHg−1, and Sc, 0.017 (± 0.002 SE) mmHg−1. Alterations in tracheal collapsibilty were also evidenced by significant reductions in resistance to airflow when the tracheae were subjected to compressive forces. Altering both smooth muscle tone (acetylcholine administration) and longitudinal length simultaneously (Group IV) produced results similar to those obtained for Group III. These data help to define the functional characteristics of immature airways and may provide insight for more effective clinical management of the premature infant.
Lung volume changes during histamine‐induced bronchoconstriction in recurrently wheezy infants
Authors: Maxwell David L. , Prendiville Anne , Rose Alison , Silverman Michael
Published: March 2007

Respiratory inductance plethysmography was used to estimate changes in functional residual capacity (FRC) in seven recurrently wheezy infants undergoing histamine challenge. Inhalations of normal saline and doubling concentrations of histamine were given up to and including the provoking concentration (PC) that caused a significant fall in maximum flow at FRC (Vmax FRC) as measured using the inflatable jacket technique. Below the PC histamine in general caused small increases in FRC [9.4 ± 7.6 ml (mean ± SD) at half the provoking concentration]. However, larger increases were seen at the provoking concentration (26.6 ± 15.6 ml). Inspection of flow‐volume curves obtained before and after the larger changes in FRC suggested that the reduction in airflow measured by the change in Vmax FRC was underestimated.
Update on pediatric chest imaging
Authors: Eggleston Daniel E. , Slovis Thomas L. , Watts Frederick B.
Published: March 2007

Even in the high‐technology medical imaging arena, the decision of how to first image pediatric chest disease is quite simple: by plain chest radiograph, including frontal and lateral views. The diagnosis can often be made or suggested on the basis of these films or with other basic imaging procedures, such as fluoroscopy or esophagram. From this point onward the decision how to proceed with further imaging such as ultrasound, computed tomography, nuclear medicine imaging, or magnetic resonance imaging, will depend on the probability of gaining further helpful information. Beginning with a concise differential diagnosis allows one to proceed in a logical manner through the diagnostic work‐up in a timeeffective and cost‐effective manner. One must keep in mind that in some cases the diagnosis cannot be made radiologically and must be left to the pathologist. In these cases the work‐up should end when no further progress is possible toward making the diagnosis. In the pediatric age group, one should always strive to limit the amount of unnecessary radiation exposure.