bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of ventilatory mechanical impedance in infants using a head pressure generator
Authors: Marchal F. , Peslin R. , Duvivier C. , Gallina C. , Crance J. P.
Published: March 2007

Two methods of measuring ventilatory mechanical impedance (Z) by forced oscillations between 6 and 20 Hz were compared in 24 infants aged 2 to 49 months: (1) the application of pressure oscillations at the airway opening (Z1); and (2) the application of pressure oscillations around the head (Z2). The latter has been recently proposed to minimize the influence of compliant upper airway walls (Peslin et al., J Appl Physiol. 1985, 59:1790–1795). Ventilatory resistance and compliance (Rsb, Csb) were also obtained with the single breath method. The real part of Z1 (R1) was markedly lower than that of the corresponding Z2 (R2), at any frequency. R1 exhibited a systematic negative frequency dependence, in contrast with R2. At any frequency, the slope of the regression equation on Rsb was closer to unity for R2 than for R1. The imaginary part of Z1 (X1) was negative over the whole frequency interval, and negative values of inertance were derived from X1. X2 was negative at low and positive at high frequencies. Resonant frequency (mean ± SD = 10.5 ± 3.5 Hz) was always reached with Z2 and correlated negatively with body weight (r = −0.61). Inertance estimated from X2 was positive and correlated negatively with body height (r = −0.66). The compliance derived from Z1 (C1 = 3.35 ± 2.32 103 L·cm H2O−1) was not significantly different from that derived from Z2 (C2 = 2.99 ± 2.02 10−3 L·cm H2O−1). The marked difference observed between Z1 and Z2 is related to the importance of the upper airway shunt and may be explained by inaccuracies of both methods. The ventilatory system impedance (Zrs) is underestimated by Z1 because some of the flow through the flowmeter does not reach the airway, and is overestimated by Z2 because some of the flow from the subject does not reach the flowmeter. The latter effect is negligible in mouth breathers, but becomes quite substantial in nose breathers. Although computer simulations suggest that the error in estimating Zrs from Z2 appears to be lower than that resulting from Z1, the potential benefit offered by the routine use of a head generator in infants remains to be established. Pediatr Pulmonol 1989; 7:209–216.
Outcome of mechanical ventilation in children with acquired immunodeficiency syndrome
Authors: Marolda Joanne , Pace Bella , Bonforte Richard J. , Kotin Neal , Kattan Meyer
Published: March 2007

We retrospectively reviewed the records of 18 children with acquired immunodeficiency syndrome (AIDS) who required mechanical ventilation for respiratory failure. These patients represented 35% of the patients seen with pulmonary disease and AIDS. The most common causes of respiratory failure were Pnuemocystis carinii pneumonia (77%) and bacterial pneumonia (33%). Bronchial lavage by fiberoptic bronchoscopy or endotracheal tube suctioning in mechanically ventilated children with AIDS had a high yield for P. carinii. Eight of 18 (44%) children survived the episode of respiratory failure and were weaned from the ventilator. However, four of eight survivors died within 6 months. Arterial oxygen tension on admission and maximum peak inspiratory pressure on the ventilator did not differ between survivors and non‐survivors. We conclude that children with AIDS who are mechanically ventilated can be weaned from the respirator but that the subsequent course remains poor. Pediatr Pulmonol 1989; 7:230–234.
Clinical significance of airway responsiveness in children of low birthweight
Authors: Chan K. N. , Elliman A. , Bryan E. , Silverman M.
Published: March 2007

We report a prospective study of airway responsiveness in a cohort of 121 children of low birthweight (under 2,000 g) at 7 years and a random sample of 100 local schoolchildren of the same age. A positive airway response was defined as a 20% fall in peak expiratory flow rate in response to a cumulative histamine dose of 3 μmol or less. We found a moderate increase in airway responsiveness to inhaled histamine in the cohort (44%) compared with the reference group (22%). There was no significant association between airway responsiveness and any perinatal variables including the level of respiratory support. The findings suggested that neonatal respiratory illness or its treatment did not play a major role in determining the long‐term airway responsiveness in these children. Amongst all factors examined, reduced airway function at the age of 7 was most strongly associated with airway responsiveness, independent of perinatal and familial factors. Airway responsiveness was associated with significantly more chest symptoms. We suggest that increased airway responsiveness to inhaled histamine in low birthweight children is a consequence rather than the cause of reduced airway function and argue against the presence of any other form of airway dysfunction as a cause of airway responsiveness. Pediatr Pulmonol 1989; 7:251–258.
Prematurity is associated with abnormal airway function in childhood
Authors: Galdès‐Sebaldt Michèle , Sheller J. R. , Grogaard Jens , Stahlman Mildred
Published: March 2007

To evaluate the long‐term effect of prematurity and/or hyaline membrane disease (HMD) on pulmonary function and airway reactivity, we studied 49 prematurely born children aged 10 to 13 years. They were divided into three groups according to birth weight and HMD status: Groups I and II comprised the children weighing less than 1,500 g at birth, and Group III those whose birth weight exceeded 1,500 g. Children without HMD at birth were classified as Group I and those with HMD as Group II or III. We performed both pulmonary function tests and methacholine (MCh) challenges and compared the results with those of 27 age‐matched controls born at term. We found that FEV1 and RV/TLC ratios were significantly different from control values in the groups with birth weights less than 1,500 g, regardless of their HMD status (Groups I and II). In Group I, results for FEF25–75%, V̇max50%, and DLCO were lower than those of controls. Airway reactivity was significantly increased in Groups I and II. A 20% drop in FEV1 after MCh challenge was found in 88%, 62%, 53%, and 36% of children in Groups I, II, and III and controls, respectively, and a 35% drop in SGaw occurred in 87%, 88%, 53%, and 59%. We conclude that prematurity and not HMD per se leads to long‐term pulmonary abnormalities and to an increase in nonspecific airway reactivity. Pediatr Pulmonol 1989; 7:259–264.
Prospective pneumogram recordings in preterm infants with and without clinical apnea and bradycardia
Authors: McCulloch Kristine M. , Kelly Dorothy H.
Published: March 2007

Recordings of breathing movements and heart rate (pneumograms) were obtained prospectively in 89 preterm infants at 0–28 days of age to determine if those who develop apnea and/or bradycardia with cyanosis (Group 1) differ from those who do not (Group 2). The 148 pneumograms were blindly analyzed for periodic breathing, bradycardia, longest apnea, and quiet time. Pneumograms were compared between groups at weekly intervals during the first 4 weeks. Significant differences were found among infants who had pneumograms recorded during the 1st week of life. Although mean gestational age and mean postconceptional age at recording were similar, birthweight and weight at recording were significantly lower in Group 1 infants. Total time spent in periodic breathing and the longest episode of periodic breathing were significantly greater in Group 1 infants. Logistic regression analysis revealed significant independent relationships between birthweight and periodic breathing at ≤7 days of age and the occurrence of symptomatic apnea and/or bradycardia. It is concluded that preterm infants who develop apnea and/or bradycardia with cyanosis have a lower mean birthweight and mean weight at recording at ≤7 days of age than similar asymptomatic preterm infants. Periodic breathing at ≤7 days of age is associated with the occurrence of clinical symptoms of apnea and/or bradycardia. Normal pneumogram values for groups of 6–21 asymptomatic preterm infants are provided for the first 4 weeks of life. Pediatr Pulmonol 1990; 8:33‐39.
Titration of continuous positive airway pressure by the pattern of breathing: Analysis of flow‐volume‐time relationships by a noninvasive computerized system
Authors: Schulze Andreas , Mädler Hans‐Jürgen , Gehrhardt Bernd , Schaller Peter , Gmyrek Dieter
Published: March 2007

Infants can defend or even dynamically elevate their functional residual capacity with additional respiratory muscle work by retarding early expiratory airflow (V̇) with postinspiration inspiratory muscle activity and/or laryngeal narrowing, or by starting inspiration before expiration to the relaxation volume has been completed.

In order to study the effect of continuous positive airway pressure (CPAP) on both phenomena in 23 infants (birthweight 1,746 ± 417 g), we elevated the airway pressure stepwise in 0.2 kPa increments. A computerized bedside flow‐volume (V̇/V) analysis was used for evaluation. In 16 “responders” early expiration braking decreased and “premature inspiratory interruption” was postponed at an “appropriate CPAP level.” The linear segment (relaxation line) of the V̇/V‐loop was lengthened until expiratory time reached a maximum. Elevation of CPAP beyond this level again produced a rapid, shallow pattern, often combined with flow acceleration late in expiration (recruitment of expiratory muscles). In the remaining seven infants (non‐responders) these latter signs of excessive airway pressure already occurred at the lowest CPAP levels applied during the “titration trials.” Respiratory rate without CPAP was different between responders (84 ± 17/min) and non‐responders (46 ± 17/min). This approach for determining the appropriate CPAP level might reduce the risk of respiratory muscle fatigue. Pediatr Pulmonol 1990; 8:96‐103.
Adult respiratory distress syndrome in severely neutropenic children
Authors: Sivan Yakov , Mor Celia , Al‐Jundi Sana , Newth Christopher J. L.
Published: March 2007

It has been suggested that polymorphonuclear cells (PMNs) are required for the development of the adult respiratory distress syndrome (ARDS). We investigated the occurrence of ARDS with acute respiratory failure in 30 children with severe neutropenia (<500 PMNs/mm3) who met the clinical diagnostic criteria for ARDS and in whom postmortem histopathology findings were available within 7 days of the onset of ARDS. In 26 patients the histopathology was consistent with ARDS. In 12/26 children no white blood cells (WBC) were found in the lung tissue, 10/26 had moderate infiltration of mononuclear cells, 2/26 had massive tumor cell infiltration, and in 2/26 PMNs were found. Thus, in at least 22/26 patients ARDS developed without neutrophilic infiltration of the lungs. The maximum active lung infection rate was found to be 69% (18/26) by endotracheal and post mortem lung cultures and histology. Thus 5/26 children had ARDS without any WBC in the lung tissue. We conclude, as have other studies in adults that the absence of PMNs does not protect children from the development of ARDS and that the mechanism which involves PMNs is probably only one of several pathways for diffuse alveolar damage, some of which is neutrophil‐independent. Pediatr Pulmonol 1990; 8:104‐108.
Effects of indoor air pollution on lung function of primary school children in Kuala Lumpur
Authors: Azizi B. H. O. , Henry R. L.
Published: March 2007

In a cross‐sectional study of 7–12 year‐old primary school children in Kuala Lumpur city, lung function was assessed by spirometric and peak expiratory flow measurements. Spirometric and peak expiratory flow measurements were successfully performed in 1,214 and 1,414 children, respectively. As expected, the main predictors of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow between 25% and 75% of vital capacity (FEF25–75), and peak expiratory flow rate (PEFR) were standing height, weight, age, and sex. In addition, lung function values of Chinese and Malays were generally higher than those of Indians. In multiple regression models which included host and environmental factors, asthma was associated with significant decreases in FEV1, FEF25–75, and PEFR. However, family history of chest illness, history of allergies, low paternal education, and hospitalization during the neonatal period were not independent predictors of lung function.

Children sharing rooms with adult smokers had significantly lower levels of FEF25–75. Exposures to wood or kerosene stoves were, but to mosquito repellents were not, associated with decreased lung function. Pediatr Pulmonol 1990; 9:24–29.
Estimation of intrapleural pressure in the newborn
Authors: Mayock Dennis E. , Watchko Jon F. , Standaert Thomas A. , Woodrum David E.
Published: March 2007

We examined the changes in esophageal (Pes), proximal airway (Paw), and direct intrapleural (Ppl) pressure measurements following end‐expiratory airway occlusion in anesthetized spontaneously breathing newborn piglets. Simultaneous occluded pressure measurements were obtained during resting ventilation, inspiratory resistive loaded (IRL) breathing, and bilateral transvenous phrenic nerve stimulation. During spontaneous resting ventilation, occluded Paw/Ppl averaged 104 ± 4% and occluded Pes/Ppl averaged 89 ± 3%. Similar values were found for occluded spontaneous breaths with IRL. During phrenic nerve stimulation at end‐expiratory lung volume, occluded Paw/Ppl averaged 104 ± 6% while occluded Pes/Ppl decreased to 70 ± 22%. We conclude that proximal airway pressure more accurately reflects intrapleural pressure than esophageal pressure with occlusion in newborn swine. During phrenic nerve stimulation, esophageal pressure measures are grossly inaccurate estimates of intrapleural pressure with occlusion. Pediatr Pulmonol 1990; 9:30–33.
Pulmonary function in infancy and in childhood following mechanical ventilation in the neonatal period
Authors: Lebourges F. , Moriette G. , Boulé M. , Delaperche M. F. , Relier J. P. , Gaultier C.
Published: March 2007

Pulmonary function was evaluated in both infancy and childhood in the same 19 prematurely born infants, who required mechanical ventilation (MV) during the neonatal period. Results of our patients were compared with those of control subjects. Upon first evaluation, we found that lung resistance (RL) was significantly elevated (24.85 ± 6.06 vs. 17.77 ± 2.39 cmH2O/L/s; P < 0.01). The mean value of dynamic lung compliance (CLdyn) was low, but the difference compared to controls did not reach significance. From infancy to childhood, elevated RL persisted (9.33 ± 2.51 vs. 6.52 ± 1.52 cm H2O/L/s; P < 0.01), and the decrease of CLdyn became significant (46.86 ± 12.84 vs. 59.34 ± 15.68 mL/cmH2O; P < 0.05). In addition, maximum flow at functional residual capacity was significantly decreased (0.824 ± 0.284 vs. 1.215 ± 0.358 L/s; P < 0.01); whereas pulmonary diffusing capacity for carbon monoxide was similar in the patients (7.62 ± 2.16 mL/min/mm Hg) and in the controls (8.38 ± 1.6). Pulmonary dysfunction following premature birth, respiratory distress, and prolonged MV may not resolve from infancy to childhood. Pediatr Pulmonol 1990; 9:34–40.
Peak expiratory flow measured with the mini wright peak flow meter in children
Authors: Sanz José , Martorell Antonio , Saiz Rosa , Alvarez Vicente , Carrasco José I.
Published: March 2007

We established pediatric reference values for peak expiratory flow rate (PEFR), using the Mini Wright Peak Flow Meter. The study was based on 1,566 Mediterranean white children, aged 7 to 14 years from Valencia (Spain) schools. Height was the biometric variable with the greatest correlation to PEFR in both sexes; significant differences were noted between males and females. Prediction equations and percentile tables are presented for each sex. The performance of the Mini Wright Peak Flow Meter was compared with that of a spirometer. Pediatr Pulmonal 1990; 9:86–90.
Use of a touch sensitive screen and computer assisted image analysis for quantitation of developmental changes in pulmonary structure
Authors: Deoras Kiran S. , Wolfson Marla R. , Searls Robert L. , Hilfer S. Robert , Sheffield Joel B. , Shaffer Thomas H.
Published: March 2007

The extensive changes in pulmonary function occurring during early development may reflect variations in the anatomic structure of the respiratory apparatus during this period. Accurate definition of these alterations could yield important information concerning the structure‐function correlations of the respiratory system. To facilitate the acquisition of morphometric data from histologic sections of pulmonary tissues, we propose the use of a computer assisted image analysis system with a touch sensitive screen as an interactive peripheral. This allows planimetric measurements and computation of the dimensions of areas of selected light intensities within an image. We present the description, design, and applications of such an image analysis system and report representative results regarding developmental changes in pulmonary structure. In addition, we correlate these results with previously published information regarding pulmonary mechanics during early development to help clarify the maturational changes in pulmonary structure‐function relationships. Pediatr Pulmonal 1990; 9:109–118.
Tracheal agenesis: An exceptional cause of neonatal respiratory distress
Authors: Brichard Bénédicte , Smeets Eric , Withofs Léon , Gillerot Yves , Battisti Oreste , Langhendries Jean‐Paul , Bertrand Jean‐Marie
Published: March 2007

The absence of the trachea is a rare and always lethal congenital malformation. Temporary survival depends on ventilation through the esophagus.

We report our experience with a newborn who presented this unusual tracheal abnormality in association with cardiac malformation. Pediatr Pulmonal 1990; 9:119–120.
Aerosolized budesonide in asthmatic infants: A double blind study
Authors: van Bever H. P. , Schuddinck L. , Wojciechowski M. , Stevens W. J.
Published: March 2007

The efficacy of nebulized budesonide (0.5 mg b.i.d.) against placebo was evaluated in the management of asthma in 23 infants, aged 3 to 17 months, using a double blind crossover design. After an initial treatment period of 2 weeks placebo and budesonide were randomly administered during two consecutive treatment periods of 1 month. The progress of the patients was monitored using diary score cards, the number of salbutamol doses needed during the treatment periods, clinical examinations using standardized scoring cards, and registration of parents' preference period. Although there was a tendency toward fewer wheezing periods during budesonide, the results of the diary score cards were not significantly different between the budesonide period and the placebo period. The number of salbutamol doses used was also the same during both periods. Clinical examination after budesonide revealed less rhinitis and a less pathological lung auscultation, but the difference between the two periods was also not significant. Furthermore, the parents' preference could not distinguish between budesonide and placebo. We conclude that the trends in favor of nebulized budesonide are not significant and do not suggest that the suspension is effective in severe infantile asthma. Pediatr Pulmonal 1990; 9:177–180.
Should TGV be measured from end‐inspiratory occlusions rather than end‐expiratory occlusions in wheezy infants?
Authors: Lanteri Celia J. , Raven Joan M. , Sly Peter D.
Published: March 2007

It has been suggested that thoracic gas volume (TGV) measured in infants in a plethysmograph most accurately represents true lung volume when calculated from end‐inspiratory airway occlusions. The rationale proposed is that pressure measured at the mouth underestimates alveolar pressure more at end‐expiration than at end‐inspiration, presumably due to small airway closure, and this results in greater overestimation of TGV. To investigate this possibility we calculated TGV in 40 wheezy infants from occlusions at both end‐inspiration (TGVei) and end‐expiration (TGVee) using a 60 L whole body plethysmograph. TGV was corrected for equipment dead space and tidal volume. When a significant change in TGV was defined as lying outside the 95% confidence interval of the TGVee measurements, 8 of the 40 infants tested had significantly higher TGV values measured from occlusions made at end‐expiration, while two infants had significantly lower TGV values measured from occlusions made at end‐expiration. This trend was not more common in infants with “concave” flow‐volume curves. Although it is technically easier to make occlusions at end‐expiration, occluding at end‐inspiration may minimize errors of TGV measures in a few individuals due to small airway closure at low lung volumes. Pediatr Pulmonal 1990; 9:214–219.
Analysis of expiratory pattern for monitoring bronchial obstruction in school‐age children
Authors: Cutrera Renato , Filtchev Slavi I. , Merolla Rocco , Willim Grzegorz , Haluszka Janusz , Ronchetti Roberto
Published: March 2007

This study was designed to assess the validity of the percent of volume expired at tidal peak flow (dV/Vt) as an indicator of bronchial obstruction in school‐age children. We analyzed 126 dV/Vt ratios and compared them with spirometric and plethysmographic results measured in 24 healthy (14 males) and 60 asthmatic (41 males) children; 42 of them underwent measurements before and after bronchial challenge with histamine. The two groups differed in resistance, forced expiratory volume in 1 sec (FEV1), and forced expiratory flows, as percents of predicted (FEV1: 94.6 ± 2.4% in controls vs 86.7 ± 1.6% in asthmatics; P<0.001). They did not differ in peak expiratory flow (PEF), forced vital capacity, functional residual capacity, measured by body plethysmography, and in d/Vt. The dV/Vt was found to correlate with FEV1 (r=0.58, P<0.001), PEF (r=0.57, P<0.001), and other lung function parameters. Forty‐two of the asthmatic children performed a bronchoprovocation histamine test. The fall of dV/Vt after histamine was significantly correlated (r=0.61, P<0.001) with the variation in FEV1 and other lung function parameters. We conclude that dV/Vt is a good indicator of bronchial obstruction, as useful in school‐age children as in adults and infants, with no need for the subject's cooperation. Pediatr Pulmonol 1991; 10:6–10.
Activated polymorphonuclear leukocytes inhibit phosphatidylcholine synthesis in cultured type II alveolar cells
Authors: Zimmerman Jerry J. , Lewandoski June R.
Published: March 2007

Activated human neutrophils (PMNs) were demonstrated to inhibit total de novo phosphatidylcholine (PC) synthesis in monolayered rat alveolar type II cells (T2C). Non‐activated PMNs had no effect on PC synthesis in this system. The magnitude of inhibition of T2C PC synthesis by phorbol myristate acetate‐activated PMNs in six experiments averaged 59.0 ± 13%. Exogenous chelated iron (ferric pyrophosphate) did not appear to augment the PMN‐mediated inhibition of T2C PC production in this model. Alpha‐1‐antiprotease usually provided no protection relative to the PMN insult towards the T2C. However, superoxide dismutase and catalase alone or in combination generally provided a significant, protective effect. Although activated PMNs consistently decreased T2C PC synthesis, this effect did not appear to involve generalized T2C cytotoxicity, as assessed by lack of release of cytosolic lactate dehydrogenase. These results indicate that PMNs can inhibit T2C PC synthesis in vitro, probably via oxyradical injury. This type of pulmonary host autoinjury may be operative in a variety of acute lung injury syndromes involving pulmonary sequestration of activated PMNs. Pediatr Pulmonol 1991; 10:164–171.
A Randomized Placebo‐Controlled Study to Evaluate the Effects of Oral Albuterol on Pulmonary Mechanics in Ventilator‐Dependent Infants at Risk of Developing BPD
Authors: Stefano John L. , Bhutani Vinod K. , Fox William W.
Published: March 2007

Albuterol is a specific beta‐2 agonist that has been reported to be effective in treating infants and children with bronchospastic pulmonary disease. The use of oral albuterol has not been investigated in patients with bronchopulmonary dysplasia (BPD). Thirty premature infants were randomized to receive oral albuterol (0.15 mg/kg/dose q8h) or a volume‐ and color‐matched placebo (D5/W). Pulmonary functions were evaluated at baseline and at 48 and 96 hours after entry to the study. The study was also designed for crossover from placebo to albuterol or albuterol to caffeine in the event that the infant's total pulmonary resistance did not improve at the time of the 48 hour pulmonary function evaluation. Heart rate and respiratory rate showed a statistically significant but clinically unimportant increase in the albuterol‐treated infants. There were no significant differences noted in systolic or diastolic blood pressure. Percent improvement in the pulmonary function indices were calculated from baseline to 48 hours and from baseline to 96 hours for the placebo and albuterol‐treated groups. The results indicate that at 48 hours there were statistically significant improvements in total resistance (14.5%), inspiratory resistance (10.8%), and expiratory resistance (12.9%) in the albuterol‐treated infants as compared to the spontaneous deterioration of the same values by 25%, 81%, and 11%, respectively, in the placebo‐treated infants. In conclusion, oral albuterol therapy of 48 hours duration improved pulmonary resistance without major cardiovascular side effects in ventilator‐dependent premature infants. Pediatr Pulmonol 1991; 10:183‐190.
Effect of salbutamol on specific airway resistance in infants with a history of wheezing
Authors: Orlowski Leszek , Zychowicz Czeslaw , Migdal Marek , Gutkowski Piotr
Published: March 2007

The purpose of this study was to assess the effectiveness of nebulized salbutamol in infants with a history of wheezing. Eighty‐eight children aged 3–24 months with a history of wheezing were studied, in seven groups: I (n = 15) and I/A (n = 17) with elevated specific airway resistance (SRaw); II (n = 17) with normal SRaw; III (n = 23), III/A (n = 17), and IV (n = 18) with normal SRaw exposed to carbachol bronchial challenge (CBC); and V (n = 13) serving as control. Infants for groups I/A and III/A were selected to match by age and by baseline and post‐carbachol SRaw values, respectively. Baseline airway resistance and thoracic gas volume (TGV) were measured plethysmographically. Specific airway resistance was selected as an index of bronchial function. Thereafter every child in groups I, I/A and II inhaled 200 μg of salbutamol by tidal breathing, and the children in groups III, III/A, and IV were exposed to CBC. Following positive reaction to carbachol, children of groups III and III/A inhaled salbutamol (200 μg, tidal breathing), and those of group IV received no drug. Controls from group V with normal SRaw received placebo (phosphate‐buffered saline). Plethysmography was repeated in all children at 5 minute intervals.

Following salbutamol SRaw was reduced in children with elevated and normal SRaw. In contrast, children not receiving salbutamol had unchanged SRaw value. The response to salbutamol measured by SRaw, Raw, and TGV was not significantly different in the spontaneously obstructed infants compared to those who received carbachol.

In conclusion, infants with a history of wheezing do respond to inhaled salbutamol. Pediatr Pulmonol 1991; 10:191–194.
Birthweight, early passive respiratory system mechanics, and ventilator requirements as predictors of outcome in premature infants with respiratory failure
Authors: Kirpalani Haresh , Schmidt Barbara , Gaston Susan , Santos Rosa , Wilkie Rosalie
Published: March 2007

Early respiratory mechanics have been reported to predict outcome in newborns with respiratory failure. However, it remains unknown whether measurements of pulmonary function add significantly to the predictive value of more readily available variables such as birthweight. The present study was designed to answer this question. Passive respiratory system mechanics were measured by an airway occlusion technique in 104 ventilator‐dependent premature infants between 6 and 48 hours of life and corrected for infant size. A ventilation index [FiO2 × mean airway pressure (MAP)] was calculated at the time of pulmonary function testing. Poor outcome was defined as death from respiratory failure or need for supplemental oxygen at 28 days. Stepwise logistic function regression examined whether ventilation index and respiratory mechanics added predictive power over and above birthweight. Five infants died, and 45 patients required supplemental oxygen at 28 days. Birthweight was a strong predictor of outcome (P < 0.00005) and would have entered the logistic model first in any case. Ventilation index added significantly to the predictive model (P = 0.038). Respiratory system conductance (P = 0.15) and compliance (P = 0.93) entered on the third and last step, respectively. We conclude that in premature infants with respiratory failure, birthweight is a strong predictor of outcome. Early ventilator requirements but not respiratory system mechanics, add significantly to this predictive model. Pediatr Pulmonol 1991; 10:195–198.
Luminal surfaces of fetal rat alveolar type II and clara lung cells react with antibody to heymann nephritis antigen
Authors: Kotas Robert V. , Kanalas John J. , Tio Fermin O. , Makker Sudesh P.
Published: March 2007

We have used affinity purified antibody, which reacts with the renal antigen gp600, to examine the immunoreactivity of pulmonary cells in the quick frozen lung tissue of fetal rats. On immunoelectron microscopy, we found that the reaction was specifically localized to the luminal surfaces of Clara cell and, as previously reported, to alveolar type II cell (ATII) membranes. No immunoreaction was seen on or in type I cells, endothelial cells or any other lung or blood cell. These studies suggest that the anti‐gp600 immunoselection can be used as a marker to identify and quantify Clara and ATII cells in rat lung tissue. Pediatr Pulmonol 1991; 10:260–266.
Cold air challenge of airway reactivity in children: A correlation of transcutaneously measured oxygen tension and conventional lung functions
Authors: Eber Ernst , Varga Eva‐Maria , Zach Maximilian S.
Published: March 2007

For pharmacological challenges, a correlation between the induced changes of the transcutaneously measured oxygen tension (Ptc) and of conventional pulmonary function tests (PFTs) has been documented. We performed a 4‐minute cold air challenge (CACh) in 17 children with bronchial asthma under continuous monitoring of Ptc, and correlated observed changes with CACh‐induced alterations of conventional PFTs. Ptc decreased significantly with CACh (from 86 ± 10 mmHg to 66 ± 14 mmHg, P < 0.001), but returned to near‐baseline within the next 30 minutes. PFTs changed with a similar pattern; the closest correlation was found between the CACh‐induced fall of Ptc and Delta‐FEV1 (r = 0.833, P < 0.001). Changes of FVC, PEF, and Vmax50 correlated significantly as well. Ptc can complement or substitute for conventional PFTs in assessing the response to CACh in children. Pediatr Pulmonol 1991; 10:273–277.
Spontaneous changes in bronchial responsiveness in children and adolescents: An 18‐month follow‐up
Authors: Backer V. , Groth S. , Dirksen A.
Published: March 2007

The purpose of this study was to investigate spontaneous changes in bronchial responsiveness to inhaled histamine over a period of 18 months. The first measurements in 495 subjects, 7 to 16 years of age, were made in 1986. Bronchial hyperresponsiveness (BHR), i.e., PC‐20 FEV1 ⩽ 8.0 mg/mL, was found in 79 (16%) individuals, of whom 28 (35%) had symptoms of asthma. Twenty asthmatic and 42 non‐asthmatic subjects who had BHR (78%) were re‐examined 18 months later. The asthmatics had a modest change in BHR, while in the non‐asthmatics bronchial response to inhaled histamine and exercise was significantly decreased. In twenty‐two subjects (36%) bronchial response was within the normal range; of these 18 were non‐asthmatic. Six asthmatics (30%) and two non‐asthmatics (5%) had an increased BHR at follow‐up. Two subjects (5%) developed symptoms of asthma by the time of follow‐up, with an unchanged degree of BHR. Sex, age, atopic symptoms, and viral respiratory infections at the first examination were unrelated to changes in bronchial responsiveness. However, changes of BHR in the non‐asthmatic subjects were significantly correlated to changes in bronchial response to exercise. Although spontaneous changes in bronchial responsiveness occur in asthmatic, as well as non‐asthmatic subjects, asthmatics persistently have hyperresponsive airways. Development of asthma was found to occur among subjects with persistent BHR. Pediatr Pulmonol. 1991; 11 :22‐28.
Interaction between chest wall motion and lung mechanics in normal infants and infants with bronchopulmonary dysplasia
Authors: Allen Julian L. , Greenspan Jay S. , Deoras Kiran S. , Keklikian Esteban , Wolfson Marla R. , Shaffer Thomas H.
Published: March 2007

Asynchronous or paradoxic motion between the rib cage and abdomen may be seen in infants with lung disease. We have recently shown that after bronchodilator administration, the degree of asynchrony decreases proportionately to the improvement in lung mechanics. However, whether such thoraco‐abdominal asynchrony (TAA) is a useful indicator of lung function in a cross‐sectional population, i.e., whether asynchrony correlates with baseline lung mechanics, is unknown. Therefore, we quantitated the degree of TAA using respiratory inductive plethysmography during quiet sleep in ten infants with bronchopulmonary dysplasia (BPD) and six weight‐matched control infants. We displayed abdominal wall (AB) and rib cage (RC) motion on an X‐Y recorder, and from the tidal breathing loop we calculated a phase angle Φ, between 0° and 180° as an index of asynchrony (synchronous RC/AB motion = 0°, paradox = 180°). Lung resistance (RL) and compliance/kg (CL/kg) were calculated from esophageal and mouth pressure, tidal volume, and tidal flow. As expected, BPD infants had abnormally high RL, and low CL/kg when compared to controls. All infants with BPD displayed marked thoraco‐abdominal asynchrony (Φ = 102 ± 16°, mean ± SEM; range 35°–160°) while controls displayed synchronous chest wall motion (Φ = 8 ± 3°, range 0°–15°) (P < 0.001). The degree of TAA was significantly correlated with RL (r = 0.773, P < 0.001) and inversely correlated with CL/kg (r = −0.67, P < 0.01). We conclude that in infants of similar weight, TAA may be used as a cross‐sectional index reflecting both resistive and elastic properties of the lungs. Pediatr Pulmonol. 1991 ; 11 :37‐43.
Clinical observations on lower respiratory tract infections with special reference to serum IgE levels
Authors: Nagayama Yoko , Sakurai Nobukiyo
Published: March 2007

To examine if the occurrence of wheezing among children with lower respiratory tract infections is associated with atopic predisposition, serum levels of IgE were determined for groups of children with or without wheezing, during infection with Mycoplasma pneumoniae or respiratory syncytial virus (RSV). In M. pneumoniae infection, more than 60% of wheezy children over 2 years of age showed a high IgE level (200 IU/mL or more), while IgE levels were less than 200 IU/mL in 73% of non‐wheezy children. In RSV infection, the incidence of high IgE levels among wheezy children was nearly double that of non‐wheezy children, although the difference was not significant. These results suggest that in children an allergic disposition is involved in the occurrence of wheezing during the course of lower respiratory tract infections.Pediatr Pulmonol. 1991; 11:44‐48
Subacute effects of respiratory syncytial virus infection on lung function in lambs
Authors: Wagner M. H. , Evermann J. F. , Gaskin J. , McNicol K. , Small P. , Stecenko A. A.
Published: March 2007

We examined the effects of ovine respiratory syncytial virus (RSV) infection on lung mechanics, lung histology, and airway reactivity in lambs. Nine lambs were inoculated with ovine RSV and seven control lambs with normal saline or viral media. Serum neutralization titers were obtained prior to and 3 weeks post‐inoculation (PI). Open lung biopsies were performed 1 and 3 weeks PI. Lung mechanics including dynamic compliance (Cdyn), resistance of the lung (RL), and functional residual capacity (FRC) were measured 2 and 6 weeks PI using a plethysmograph. Airway reactivity to aerosolized carbachol, citric acid, and histamine was determined 2 and 6 weeks PI. Most RSV and control lambs were asymptomatic after inoculation. Control lambs had significantly greater average daily weight gain by the third week after inoculation. Seven RSV lambs tested had a fourfold or greater rise in serum neutralization titers, while two control lambs had a fourfold increase. At 2 weeks PI, RSV lambs had significantly lower FRC and higher RL. At 6 weeks RL remained significantly elevated in the RSV lambs. Airway reactivity was not increased in the RSV group. This animal model is useful for studying the effects of RSV infection on lung growth and lung function over time. Pediatr Pulmonol. 1991 ; 11 :56‐64.
Ultrafast computerized tomography of the chest in cystic fibrosis: A new scoring system
Authors: Nathanson Ian , Conboy Kathleen , Murphy Suzanne , Afshani Ehsan , Kuhn Jerald P.
Published: March 2007

Assessing the presence and severity of bronchiectasis (BR) and mucoid impaction (MI) of the airways in cystic fibrosis (CF) is difficult by non‐invasive methods. We hypothesized that scoring ultrafast computerized tomograms (UFCT) of the chest for BR and MI could be useful in detecting early lung changes in 28 patients with CF. To do this, UFCT scores were compared to established clinical and chest X‐ray (CXR) scores. Results showed that UFCT scores correlated highly with clinical (r = 0.88) and CXR (r = 0.93) scores, and several pulmonary function tests. Regression analysis indicated that BR influenced clinical and CXR scores more than MI. Both BR and MI were found in all areas of the lungs without a major propensity for one region, although there was significantly more BR in the right upper lobe than the right lower lobe. In patients with CXR score ⩾ 21 BR was present in 8/9 and MI in 3/9, while in those with CXR score < 21 UFCT showed BR in 19/19 and MI in 17/19. We conclude: 1) scored UFCTs correlate well with CXR and clinical scores; 2) 6R influences clinical and CXR scores more than MI; 3) UFCTs detect BR and MI in CF patients with minimal evidence of pulmonary disease; and 4) CXR scores < 21 reflect the presence of both BR and MI.Pediatr Pulmonol. 1991; 11:81‐86.
Efficacy, results, and complications of mechanical ventilation in children with status asthmaticus
Authors: Cox Robin G. , Barker Geoffrey A. , Bohn Desmond J.
Published: March 2007

We have conducted a retrospective survey of 79 children out of a total hospital asthmatic patient population of 2,412, admitted over a 32 month period to the ICU for the management of severe status asthmaticus. All patients were in severe respiratory distress with CO2 retention; 19 required mechanical ventilation due to increasing fatigue and worsening bronchospasm, having failed to respond to either inhaled or IV bronchodilator therapy. All patients were ventilated at slow rates (< 12 min) and their airway pressure (Paw) was deliberately kept below 45 cmH2O, while accepting a Pa in the 45–60 mmHg range, as long as the pH was compensated. Although two patients developed pneumothoraces while on positive pressure ventilation, these were resolved without incidents. Five patients who had mediastinal or subcutaneous air leaks prior to intubation did not develop pneumothoraces. Following the initiation of mechanical ventilation, IV β‐agonist therapy was increased in order to reverse the bronchospasm and reduce the duration of mechanical ventilation. Mean duration of intubation was 42 hours. Fourteen of the 19 patients were weaned and extubated within 48 hours. All patients survived without sequelae. We conclude that a degree of controlled “hypoventilation” by deliberately choosing Paw < 45 cmH2O can be successfully used to ventilate children with severe status asthmaticus with a reduced rate of pressure‐related complications.
Asthma in the vicinity of power stations: II. Outdoor air quality and symptoms
Authors: Henry Richard L. , Bridgman Howard A. , Wlodarczyk John , Abramson Rachel , Adler Julie A. , Hensley Michael J.
Published: March 2007

To assess longitudinally the effect of living in the vicinity of coal‐fired power stations on children with asthma, 99 schoolchildren with a history of wheezing in the previous 12 months were studied for 1 year, using daily diaries and measurements of air quality. The children had been identified in a cross‐sectional survey of two coastal areas: Lake Munmorah (LM), within 5 km of two power stations, and Nelson Bay (NB), free from major industry. Daily air quality [sulphur dioxide (SO2) and nitrogen oxides (NOx)], respiratory symptoms, and treatment for asthma were recorded throughout the year.

Measurements of SO2 and NOx at LM were well within recommended guidelines although they were several times higher than at NB: maximum daily levels in SO2 (μg/m3) were 26 at LM, 11 at NB (standard, 365); yearly average SO2 was 2 at LM, 0.3 at NB (standard, 60); yearly average NOx (μg/m3) was 2 at LM, 0.4 at NB (standard, 94). Marked weekly fluctuations occured in the prevalence of cough, wheezing, and breathlessness, without any substantial differences between LM and NB. Overall, the prevalence of symptoms was low (10% for wheezing, 20% for any symptom).

Whether the daily SO2 and NOx levels affected the occurrence of respiratory symptoms was investigated in children at LM using a logistic regression (Korn and Whittemore technique). For these children as a group, air quality measurements were not associated with the occurrence of symptoms.
Retrosternal density: Pulmonary underdevelopment or accessory hemidiaphragm
Authors: Eid Nemr S. , Shearer Loretta T. , Gultekin Ebru K.
Published: March 2007

Vertical retrosternal density paralleling the sternum, with haziness of a hemithorax on chest roentgenogram, often challenges the clinical acumen of pediatricians, chest physicians, and pediatric radiologists alike. Its presence has been historically linked to either pulmonary underdevelopment and/or accessory hemidiaphragm. The surgical and radiological pediatric literature has long debated this topic, but unfortunately, it has not received much attention in the general pediatric or in pediatric pulmonology literature. The similar radiologic appearance of these two entities can cause confusion both in diagnostic and therapeutic approach. Many authors advocate an invasive modality, including thoracotomy, as the only definitive way to differentiate between them. We present two similar cases with retrosternal densities, review the pertinent literature, and propose a rational approach to diagnosis and treatment.
Comparison of six ECMO selection criteria and analysis of factors influencing their accuracy
Authors: Payne Nathaniel R. , Kriesmer Pamela , Mammel Mark , Meyer Christopher L.
Published: March 2007

This study compared six extracorporeal membrane oxygenation (ECMO) selection criteria in 42 neonates and analyzed factors influencing the accuracy of outcome predictions. The sensitivity of the criteria in identifying fatal cases varied from 0.44 to 0.94 and the specificity of predictions of survival ranged from 0.42 to 0.69. The criterion having the highest sensitivity had the lowest specificity and conversely the criterion with the lowest sensitivity had the highest specificity. Overall accuracy of the criteria, as measured by the total number of correct outcome predictions, differed little among the criteria (23/42 to 27/42 correct predictions). Three factors influenced predictive accuracy: 1) a primary diagnosis of congenital diaphragmatic hernia (CDH) was associated with a greater mortality (P < 0.001) and a significantly higher positive predictive value (PPV) for all criteria (P = 0.0009–0.012) than that seen in patients with other primary diagnoses; 2) calculating the alveolar‐arterial oxygen gradient using an assumed, rather than measured barometric pressure, or estimating oxygenation index using a calculated, rather than a measured, mean airway pressure, increased false positive mortality predictions in non‐CDH patients; and 3) requiring a peak inspiratory pressure (PIP) of at least 50 cm H2O in the definition of maximal medical management, rather than a PIP of 20–49 cm H2O, significantly increased the PPV for three of four criteria examined (P = 0.02–0.04). Awareness of these factors may facilitate the identification of neonates who need ECMO to survive.
Medical and social factors as predictors of outcome in infant tracheostomy
Authors: Singer Lynn T. , Hill Betsy P. , Orlowski James P. , Doershuk Carl F.
Published: March 2007

We examined the relative impact of infant tracheostomy in comparison to associated medical and social factors, on developmental outcome as part of a cross‐sectional follow‐up of 32 children. These children had no mental retardation, physical handicap, or severe neurological problems, but had a history of long‐term tracheostomy in infancy, ranging from 3 to 146 months duration.

Medical factors evaluated included prematurity, neurological status, severity of illness, and number of weeks hospitalized. Social factors included parental education and occupation. Outcome measures included IQ, language quotient, growth parameters, and behavioral competence. Correlation analyses, stepwise multiple regression analyses, and t‐tests were used.

Early medical illnesses were significant predictors of cognitive, language, and growth outcome. Severity of medical complications at birth and the presence of any neurological problem predicted 49% of the variance in IQ at follow‐up. Social class was the only variable to predict behavioral outcome, accounting for 28% of the variance. For children without confounding medical conditions, tracheostomy had a negative impact on overall language and auditory comprehension. Once children with confounding medical risk factors were removed from the sample, children with history of infant tracheostomy exhibited significantly lower overall mean lanugage scores (106 versus 120), and lower mean language comprehension scores (104 versus 119) than a matched comparison group.
Pilot study for the development of a monitoring device for ventilated children
Authors: Wensley D. F. , Noonan P. , Seear M. D. , Werner H. , Pirie G. E.
Published: March 2007

Airway pressure and air flow were measured at the endotracheal tube in 13 children on a variety of ventilators. These signals were stored for analysis on a computer. Further data sets were obtained after 24 hours or following major interventions. Air flow rate was integrated to give volume. Pulmonary resistance and elastance were obtained by multiple linear regression. Pressure‐volume, pressure‐flow and flow‐volume loops were plotted. “Closed” pressure‐volume and pressure‐flow loops (by subtraction of the resistive or elastic pressure components, respectively) were also displayed, giving compliance and resistance loops. The loops from the initial data set were taken as the baseline, and loops from later data sets were superimposed to provide visual comparisons. Change in clinical status was reflected by the change in slope of compliance and resistance loops. A 30% change in compliance or resistance was easily observed. There was minimal interference with patient care.

This pilot study demonstrates that changes in respiratory mechanics can be displayed safely and easily in ventilated patients using resistance and compliance loops. Further work is necessary to confirm the usefulness of real time of these displays.