Pediatric pulmonology
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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
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
Comparative StudyEffect of spontaneous and mechanical breathing on dynamic lung mechanics in hyaline membrane disease.
We measured then compared the dynamic lung mechanics of spontaneous breaths and mechanical breaths in 9 mechanically ventilated neonates with hyaline membrane disease. All were receiving intermittent mandatory ventilation. All breathed spontaneously between ventilator breaths. ⋯ Peak inspiratory and expiratory gas flows were also higher (P less than 0.01) during mechanical breathing. The spontaneous breaths generated by patients and the mechanical breaths generated by mechanical ventilators are different. The lung mechanics measurements of these two different types of breathing should be collected, analyzed, and reported separately.
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Pediatric pulmonology · Jan 1990
Evaluation of a mainstream capnometer and end-tidal carbon dioxide monitoring in mechanically ventilated infants.
We evaluated a new lightweight capnometer with a less than 1 mL deadspace neonatal airway adapter and endotracheal tube connector unit (NAC) for use in mechanically ventilated neonates. The evaluation consisted of: 1) a bench test comparison of air flow resistance between the standard endotracheal tube and connector with the new NAC (flow rates, 1.5 to 12.8 L/min); 2) a determination of the effect of NAC placement on Paco2; 3) pre- and post-NAC pulmonary mechanics; and 4) analysis of paired PetCO2 and PACO2 in 16 infants requiring mechanical ventilation. ⋯ All post-NAC placement Paco2 were smaller than pre-placement values; there were no differences in pulmonary mechanics, and Petco2 correlated closely with Paco2 (n = 132, r = 0.79) defined as Petco2 = 0.68. Paco2 + 5.52; means +/- 1 SD, Paco2 -Petco2 was 4.7 +/- 4.7 torr and Petco2/Paco2 was 0.86 +/- 0.14.