bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aerosol delivery in neonatal ventilator circuits: A rabbit lung model
Authors: Cameron Duncan , Arnot Rosemary , Clay Michelle , Silverman Michael 
Published: March 2007

AbstractThe benefits of inhaled therapy in ventilated neonates are recognized, but the reliability of drug delivery in nebulizer‐ventilator circuits is uncertain. We quantified the effect of changing variables. Twenty‐three freshly killed rabbits (1.15–1.9 kg) were ventilated via a tracheostomy by a pressure‐limited, time‐cycled ventilator (Neovent). A radioaerosol of 99Tcm pertechnetate from an Ultravent nebulizer (Mallinkrodt) was fed into the proximal ventilator tubing. Two 3‐minute nebulizations at “standard settings” were followed by 2 at altered pressure, frequency, gas flow, I:E ratio, or position of the nebulizer in the circuit. Each nebulization was followed by a 3‐minute gamma camera image and total deposited radioactivity was measured in excised lungs and trachea. Images demonstrated good peripheral aerosol deposition. At standard settings, lung deposition averaged 2.8% of the aerosol released. This was decreased markedly by reducing tidal volume (ventilator pressures) and residence time of aerosol (I:E ratio). Reduced gas flow decreased deposition slightly, presumably by increased particle size and marginally reduced tidal volume. Deposition did not change with increased frequency; increased minute ventilation was offset by decreased residence time of the aerosol. We conclude that the Ultravent nebulizer can be used to nebulize drugs in a standard neonatal circuit, although the dose delivered is small. Tidal volume and aerosol residence time are important determinants of aerosol delivery. Pediatr Pulmonol 1991; 10:208–213.
Epidemiology of cystic fibrosis in latin america: Preliminary communication
Authors: Macri Carlos N. , de Gentile Angela S. , Manterola Alberto , Tomezzoli Silvana , Reis Francisco Caldeira , Garcia Isabel Largo , Fernandez José Luis Lezana 
Published: March 2007

AbstractWe conducted a retrospective study of 743 patients with cystic fibrosis (CF), covering the 1979–89 period in 4 Latin American (LA) institutions to evaluate the clinical features of the disease. The review, although dealing only with patients referred to, or diagnosed at these institutions may be considered to comprise the majority of patients living in these areas. Diagnosis was confirmed by the sweat test in all cases. There was a slight predominance of males, (61.0%) mainly in the Brazilian group. The mean age at diagnosis was over 3 years. This was similar to the mean age at admission. Almost half of the patients were still alive at follow‐up, but their mean age was low (6.4 years in Brazil, 7.4 in Chile, 9.6 in Mexico, and 11.3 in Argentina). Mean age at death ranged from 3.1 years (Chile) to 8.7 years (Argentina). The highest proportion of living patients was in Chile (71.4%) and the lowest in Argentina (33.8%). Survival curve comprised 15 years after diagnosis for the Argentinian group, compared to 6 years for the remaining groups. Fifty percent of the patients lived 6–7 years after diagnosis in Argentina, 4–5 years in Mexico and Chile, and 3 years in Brazil. Among Argentine patients 39.2% survived to 10 years of age, and 18% to 15 years. These findings suggest that CF is not rare in LA but extensive epidemiological studies are needed to obtain accurate figures on the magnitude of the problem. Pediatr Pulmonol 1991; 10:249–253.
Effects of endotracheal tube size and ventilator settings on the mechanics of a test system during intermittent flow ventilation
Authors: Farstad Teresa , Bratlid Dag 
Published: March 2007

AbstractThe effect of varying the size of standard neonatal endotracheal tubes on delivered tidal volumes (VT), resistance (R), dynamic compliance (Cdyn), and resistive work of breathing (WOB) was measured in a test system during intermittent flow ventilation at different ventilator settings. The experiments were performed with a Sechrist infant ventilator connected to a Dräger Test Lung via standard neonatal endotracheal tubes.R, inspiratory (Ri), and expiratory resistance (Re) as well as WOB were significantly affected by endotracheal tube size. The calculated difference in Re between endotracheal tubes of 2.5 and 3.5 mm I.D. was 93 cm H2O/L/s (mean value for all studies). Cdyn and VT were also affected by endotracheal tube size. However, although statistically significant differences were found in Cdyn (mean, 0.584 mL/cm H2O and 0.567 mL/cm H2O) and VT (mean, 13.0 mL and 12.7 mL) for the tube sizes 3.5 mm and 2.5 mm I.D., respectively, the absolute numerical differences were small. Also, ventilator settings with respect to the peak inspiratory pressure (PIP) ‐ positive end‐expiratory pressure (PEEP) difference had a significant influence on Cdyn for both tube sizes. On the other hand, flow and inspiratory time adjustments had no significant effect on ventilatory parameters. Endotracheal tube size and ventilator settings should be considered when comparing the pulmonary function tests in intubated and non‐intubated newborn infants. Pediatr Pulmonol. 1991; 11:15‐21.
Asthma in the vicinity of power stations: I. A prevalence study
Authors: Henry Richard L. , Abramson Rachel , Adler Julie A. , Wlodarcyzk John , Hensley Michael J. 
Published: March 2007

AbstractRespiratory symptoms, atopy, and bronchial reactivity were measured in primary school children living in Lake Munmorah (LM), a coastal town near two power stations, and in Nelson Bay (NB), a coastal town free from any possible major sources of outdoor air pollution. A prevalence survey and longitudinal follow‐up study were performed 1 year apart. In both studies, the prevalence of ever wheezed, current wheezing, breathlessness, wheezing with exercise, diagnosed asthma, and use of drugs for asthma at LM were all approximately double the prevalence at NB (all P values < 0.01). The prevalence of bronchial reactivity was significantly greater at LM than NB (P < 0.01) at the first but not the second survey. By contrast, no significant differences were found between the two areas for skin test atopy or for parental history of allergic disease. Multivariate analysis supported the conclusion from the univariate analysis that there was more wheezing at LM compared to NB at both studies, when adjusted for atopy, smoking in the home, age, and sex. As expected, a positive skin test reaction to house dust mite was the predominant explanatory variable. Asthma was more common in the community near power stations (LM) than in the NB area. The absence of significant differences in skin test atopy and parental history of allergic disease argued against major genetic differences between the two groups. By contrast, the more common reporting of siblings' chest disease and asthma in Lake Munmorah supported an environmental cause.
Effect of airway inertance on linear regression estimates of resistance and compliance in mechanically ventilated infants: A computer model study
Authors: Turner M. J. , Macleod I. M. , Rothberg A. D. 
Published: March 2007

AbstractRespiratory inertance (I) is usually ignored when resistance (R) and compliance (C) of mechanically ventilated infants are estimated by least squares linear regression. Values of I that have been reported for these patients can cause impedances whose magnitudes approximate respiratory resistance. We show theoretically that if inertance is neglected no error is expected in resistance estimates, but a positive bias in compliance can be, proportional to the inertance, the compliance, and the sinusoidal frequency at which the measurements are made. To determine the errors in parameter estimates when the pressure waveform is non‐sinusoidal, we simulated linear regression based on non‐inertive and inertive models. R, C, and I of the simulated lung were varied over the range expected in an infant intensive care unit. The ventilator was simulated as a critically damped second order system with a square pulse input. The rise time (TR) of the pressure pulse was varied over the range reported in infant ICUs. Simulated measurements confirmed that resistance is correctly estimated if inertance is neglected. Maximum error in compliance estimates (13%) occurred when TR and R were low, and C and I were high. The variation in the error in estimated compliance was consistent with the theory. Coefficients of variation of the parameters, the standard errors, and R2 of the regressions tended to deteriorate with increasing compliance error, but the relationships were not single valued. These statistics may alert investigators to possible bias in compliance caused by neglected inertance, but cannot be used to correct any bias.
Epithelioid hemangioendothelioma of the lung (intravascular bronchioloalveolar tumor) in a young girl
Authors: Rock Michael J. , Kaufman Robert A. , Lobe Thom E , Hensley Samuel D. , Moss Max L. 
Published: March 2007

AbstractThis report describes a 7 year old girl who presented with scoliosis and a small right hemithorax. Findings on spine roentgenographs were pleural thickening on the right and parenchymal densities. Computed tomography of the chest and abdomen revealed multiple pulmonary nodules and two hypervascular lesions within the liver. The diagnosis established by lung biopsy was intravascular bronchioloalveolar tumor (epithelioid hemangioendothelioma of the lung). This is the youngest reported case of this rare tumor.
Undetected apnea and bradycardia in infants
Authors: Graff Michael , Soriano Cecilia , Rovell Kris , Hiatt I. Mark , Hegyi Thomas 
Published: March 2007

AbstractDespite routine monitoring, a number of prolonged apneic and bradycardic episodes were undetected in a group of infants in the neonatal intensive care unit (NICU). Sixty‐one infants were evaluated by 12‐hour pneumocardiograms at a post‐conceptional age of 35 ± 3 (SD) weeks. Nursing documentation failed to detect 11 infants with prolonged apnea and bradycardia. Three of these infants were not detected in spite of increased awareness following in‐service education. Such a lack of documentation may lead to improper medical management of infants at risk for pathologic apnea and suggests the need for more accurate documentation at the time of discharge.
The effect of lung mechanics on gas transport during high‐frequency oscillation
Authors: Schindler Margrid , Seear Michael 
Published: March 2007

AbstractWith the general aim of obtaining clinically relevant information on the use of high‐frequency oscillation (HFO), we examined the effects of altering oscillatory frequency (f), tidal volume (VT), and mean airway pressure (Paw) on gas exchange in rabbits, both before and after altering the animal's pulmonary mechanics by saline induced lung injury. Twenty‐seven combinations of f (5,8,12 Hz), VT (0.5, 1,2 mL/kg), and Paw (5, 10, 13 cm H2O) were used. Acute pulmonary injury was induced by instilling 10 mL/kg of warm saline into the lung. Gas exchange was assessed by steady‐state levels of arterial oxygen tension (Pa) and carbon dioxide tension (Pa). Arterial Pa was independent of f or VT before or after lung injury; it was independent of Paw before injury but highly dependent on Paw after lavage. The difference was presumably related to lung volume recruitment. Arterial Pa was dependent on f and VT but independent of Paw at any time. The relationship was modeled by the equation Pa ∝ fa · VTb where the exponents a = −0.4 and b = −0.6. Our technique of a standardized saline instillation gave a reproducible and stable model of lung injury. In damaged rabbit lungs the principles of HFO appear to be similar to conventional mechanical ventilation: oxygenation depends on Paw and inspired oxygen concentration, while CO2 removal is determined by f and VT.
Response to tube breathing in preterm infants with apnea
Authors: Upton C. J. , Milner A. D. , Stokes G. M. 
Published: March 2007

AbstractIn order to analyze the effects of maturity and apnea frequency on the respiratory control of preterm infants, we studied their responses to tube breathing using tubes equivalent to two anatomical dead spaces. Ventilation during tube breathing was expressed as a percentage above baseline and compared to an “expected” value calculated from the volume of the added tube. Twenty‐seven preterm infants (median birthweight, 1.14 kg.; and gestational age, 29 weeks) were studied on 86 occasions.The percentage of “expected” ventilation increased with post‐conceptional age (r = 0.48, slope = 3.12, P < 0.0005), from a mean of 73% at 26 weeks up to 104% at 36 weeks. Using multiple regression analysis, neither postnatal age nor apnea frequency had any effect once allowance had been made for post‐conceptional age. Although the respiratory adaptation of the most immature infants was poor, this study suggests that infants with apnea show no gross deficit in respiratory control, compared to those without apnea.
Bronchoscopy with bronchoalveolar lavage in the evaluation of pulmonary complications of bone marrow transplantation in children
Authors: McCubbin Michael M. , Trigg Michael E. , Hendricker Connie M. , Wagener Jeffrey S. 
Published: March 2007

AbstractPulmonary complications are a frequent cause of morbidity and mortality following bone marrow transplantation. We examined the results of flexible bronchoscopy (FB) and bronchoalveolar lavage (BAL) in 27 pediatric bone marrow transplant (BMT) recipients with 29 episodes of pulmonary complications. Bone marrow transplant was performed for a variety of malignancies and hematologic disorders. Median age of BMT was 10.3 years (range, 1.7–17.6 years). Median time of FB following BMT was 60 days (range, 11–1,026 days). Routine cytologic and culture techniques were utilized to detect malignant cells, viruses, fungi, bacteria, and protozoa. Positive results were found in 15 (52%) with cytomegalovirus (CMV), the most common positive finding. In 14 (48%) episodes the results were negative. Fourteen patients had follow‐up autopsy or open lung biopsy (OLB). Based on autopsy/OLB results, there were two false negatives and no false positives, giving a diagnostic sensitvity of 75% and specificity of 100%. There was one possible complication of FB and BAL. Survival of both positive and negative patients was poor, only seven patients being alive 90 days post‐FB with BAL. We conclude that FB with BAL is a safe and accurate procedure for the diagnosis of pulmonary complications of BMT.
Flexible endoscopic intubation of the neonate
Authors: Finer Neil N. , Muzyka David 
Published: March 2007

AbstractThe development of the ultrathin bronchoscope has provided a means of providing flexible endoscopic intubation for the neonate and small infant. We report our experience of 26 such endoscopic intubations in 23 neonates with birth weights form 1,200 to 4,600 g and post‐conceptional ages varying from 31.5 to 60 weeks.The most common indications for the procedure were dysmorphic airways with variable degrees of micrognathia, acquired airway lesions, and severe degrees of hydrocephalus. With the use of the current 2.2 mm and 2.7 mm diameter instruments, it is now possible to utilize this technique with 2.5 mm endotracheal tubes. There were no failed procedures and no evidence of laryngospasm, the most frequent adverse effect being a transient fall in oxygen saturation. The procedure as practiced by experienced individuals is well tolerated and is an important adjunct for intubation of neonates with dysmorphic upper airways or other disorders that prevent adequate visualization of the larynx.
Sputum cysteinyl‐leukotriene levels correlate with the severity of pulmonary disease in children with cystic fibrosis
Authors: Spencer D. A. , Sampson A. P. , Green C. P. , Costello J. F. , Piper P. J. , Price J. F. 
Published: March 2007

AbstractSputum samples from 13 children with cystic fibrosis (CF) were analyzed for leukotrienes (LTs) LTB4, LTC4, LTD4, and LTE4. Distribution of LTB4 appeared to be normal, and of cysteinyl‐LTs log normal. Total cysteinyl‐LT levels, of which on average 75% was LTE4, were nearly 10 times higher than in earlier studies. Log LTE4 and total cysteinyl‐LT levels correlated with the overall severity of pulmonary disease assessed by Chrispin—Norman chest radiograph score (Log LTE4: r = 0.701, r2 = 49.1%, P = 0.008. Log total cysteinyl‐LTs: r = 0.715, r2 = 51.1%, P = 0.006). There was no apparent relationship between LTB4 levels and Chrispin—Norman chest radiograph score, nor between the level of any of the LTs and age or organism cultured from sputum. These findings suggest that the cysteinyl‐LTs may be involved in the pathophysiology of pulmonary disease in CF. Pediatr pulmonol.1992; 12:90–94.
Variability of respiratory system compliance in mechanically ventilated infants
Authors: Muramatsu K. , Yukitake K. , Oda T. 
Published: March 2007

AbstractWe measured respiratory flow, volume by integrated flow, and airway pressure in four mechanically ventilated infants. Compliance of the respiratory system (Crs) was measured by the multiple occlusion method. Airway occlusion and release were achieved by a balloon in an occlusion valve between the endotracheal tube and a pneumotachometer, all connected in series with the respirator circuit. Values of Crs varied greatly due to changes in mean airway pressure (MAP). The Crs increased with the elevation of MAP on some occasions and decreased on others. Values of Crs also varied corresponding to different occlusion pressures for individual levels of MAP. Thus Crs changed continuously, even within a single respiratory cycle. The observed variability in Crs was explained by the following mechanism: a pressure‐volume (P‐V) loop of tidal ventilation moves its position within the pressure‐volume diagram and changes shape due to variations of the ventilator settings. In some infants the lungs were ventilated in the range of the linear portion of the P‐V diagram while in others they may have been ventilated on the flattened portion. Some patients had convex expiratory P‐V curves even with low pressure swings during tidal ventilation.
Respiratory mechanics in mechanically ventilated newborns: A comparison between passive inflation and occlusion methods
Authors: Storme L. , Riou Y. , Leclerc F. , Kacet N. , Dubos J. P. , Gremillet C. , Rousseau S. , Lequien P. 
Published: March 2007

AbstractA passive inflation method was described for measuring total respiratory elastance and resistance during mechanical ventilation in adult patients (Rossi et al., J Appl Physiol 58:1849, 1985). We applied this method to preterm and full‐term mechanically ventilated newborn infants and we compared the results with those obtained by the occlusion method. We performed 37 tests in 16 newborn infants (B.W. 880–4,500 g; G.A. 28–42 weeks), between 1 and 45 days of postnatal age, ventilated with a Servo Ventilator 900C, set in controlled‐volume mode. Flow was measured through a pneumotachograph inserted between the endotracheal tube (ETT) and the breathing circuit, tidal volume by integration of flow and airway pressure directly at the airway opening. Flow, volume, and pressure were recorded on an X/Y plotter to obtain pressure‐volume (P/V), flow‐volume (V/V) loops, and pressure‐time curves. Occlusion was performed by using the end‐inspiratory and the end‐expiratory pause buttons of the ventilator. Analysis of P/V and V/V loops provided respiratory system compliance (Crs, infl.), resistance (Rrs, infl.), and “intrinsic positive end‐expiratory pressure” (PEEPi, infl.). These values were compared with Crs, occl., Rrs, occl., and PEEPi, occl. measured by the occlusion method. The measurements were well correlated (Crs, infl./Crs, occl.: r = 0.90; Rrs, infl./Rrs, occl.: r = 0.91; PEEPi, infl./PEEPi, occl.: r = 0.91). Rrs, infl./Rrs, occl. and PEEPi, infl./PEEPi, occl. did not differ significantly. However, Crs, occl. was 15% higher than Crs, infl. (P < 0.01). The passive inflation method is simple to use and well tolerated in preterm and full‐term ventilated newborn infants, it provides accurate results, and can be a good alternative to occlusion methods. It requires, however, a constant inflation flow and adaptation to the ventilator.
Bronchoalveolar lavage fluid cytology reflects airway inflammation in beagle puppies with acute bronchiolitis
Authors: Dambro Nancy N. , Grad Roni , Witten Mark L. , Quan Stuart F. , Sobonya Richard E. , George Ray C. , Devine Linda , Lemen Richard J. 
Published: March 2007

AbstractBeagle puppies infected with both canine parainfluenza virus type 2 (CPI2) and Bordetella bronchiseptica (Bb) develop more severe acute bronchiolitis and airways hyperresponsiveness than do those infected with CPI2 or Bb alone. The aim of our study was to characterize the inflammatory response associated with airway hyperresponsiveness, and to determine whether the inflammatory cell response of bronchoalveolar lavage fluid (BALF) reflected changes in the bronchioles in this model. We investigated 25 beagle puppies (ages 76 ± 5 days, mean ± SEM) in four groups: controls (n = 6), or puppies inoculated with both CPI2 and Bb (CPI2‐Bb) (n = 11), with only CPI2 (n = 4), or only Bb (n = 4). The puppies were killed 3–4 days after inoculation, the lungs excised, the intermediate lobe lavaged, and BALF and the bronchiolar wall tissue examined for neutrophils and other inflammatory cells. Control puppies had no evidence of inflammation. However, the CPI2‐Bb puppies had developed cough and rhinitis, positive cultures for CPI2 and Bb, and a neutrophilic cellular response in both the bronchioles and the BALF. Puppies inoculated with only CPI2 or Bb had milder illnesses and no significant bronchiolar and BALF neutrophilic response. For all groups, the severity of bronchiolar wall inflammation correlated with the total number of BALF inflammatory cells, and bronchiolar wall neutrophil counts correlated with the percentage of neutrophils in the BALF. The illness and the airway hyperresponsiveness observed in the CPI2‐Bb group were associated with airway neutrophilia. Our studies support the hypothesis that neutrophils are associated with airway dysfunction in this model, and the use of BALF to study the process.