Pediatric pulmonology
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Pediatric pulmonology · Jan 1990
Comparative StudyEstimation of intrapleural pressure in the newborn.
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%. ⋯ 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.
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Pediatric pulmonology · Jan 1990
Pulmonary mechanics and energetics of normal, non-ventilated low birthweight infants.
Pulmonary mechanics and energetics were determined in 33 healthy low birthweight infants (less than 1,500 g, 28-34 weeks gestation) who had never received ventilatory support. Tidal volume, dynamic pulmonary compliance, pulmonary resistance, pressure-volume relationships, and tidal flow-volume measurements were obtained by pneumotachography and the esophageal balloon technique. Standardized data collection and software data analysis by least mean squares technique yielded data at 0.5, 1, 2, and 4 weeks postnatally, as a function of gestational age (less than 30, 30-32, and greater than 32 weeks gestation). ⋯ Changes in pulmonary mechanics resulted in increasing resistive work of breathing. Our findings suggest a postnatal retardation of pulmonary and airway growth, relative to gestation maturation. These data can provide an objective base of comparison for data in sick, low birthweight neonates.
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Pediatric pulmonology · Jan 1990
Comparative StudyPulmonary function testing prior to extubation in infants with respiratory distress syndrome.
Pulmonary function testing was performed just prior to extubation on 50 infants mechanically ventilated for treatment of respiratory distress syndrome. All infants were ready for extubation as defined by clinical criteria. Pulmonary mechanics and energetics were measured by a computerized technique that consists of a pneumotachometer to measure flow rates and an esophageal balloon and differential transducer to estimate transpulmonary pressure. ⋯ No statistically significant differences in pulmonary mechanics were seen between the two groups. Data suggests that successful withdrawal of mechanical ventilation may be related to multiple factors such as central inspiratory drive, diaphragmatic endurance, and chest wall stability, in addition to improved lung mechanics. Pulmonary function testing criteria alone may not be useful in determining optimal timing of extubation in premature infants.
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Pediatric pulmonology · Jan 1990
Relationship between infant lung mechanics and childhood lung function in children of very low birthweight.
Twenty-seven children of very low birthweight (less than or equal to 1,500 g) whose lung function had been measured on several occasions during the first year were studied at the age of about 9 years. Fifteen of the children had received neonatal intermittent positive pressure ventilation, mostly for respiratory distress syndrome. Ten of the ventilated children were still oxygen dependent at 30 days of age. ⋯ This relationship was independent of neonatal mechanical ventilation. We conclude that perinatal factors, which may be associated with disturbed lung mechanics early in infancy, are only weak and indirect predictors of childhood lung function. Airway conductance late in infancy, determined by constitutional factors, prematurity itself or other undetermined factors, is a good predictor of airway function at 9 years.
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Pediatric pulmonology · Jan 1990
Prospective pneumogram recordings in preterm infants with and without clinical apnea and bradycardia.
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. ⋯ 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 less than or equal to 7 days of age than similar asymptomatic preterm infants. Periodic breathing at less than or equal to 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.