Randomized crossover comparison of proportional assist ventilation and patient-triggered ventilation in extremely low birth weight infants with evolving chronic lung disease

Background: Refinement of ventilatory techniques remains a challenge given the persistence of chronic lung disease of preterm infants. Objective: To test the hypothesis that proportional assist ventilation ( PAV) will allow to lower the ventilator pressure at equivalent fractions of inspiratory oxygen (FiO(2)) and arterial hemoglobin oxygen saturation in ventilator-dependent extremely low birth weight infants in comparison with standard patient-triggered ventilation ( PTV). Methods: Design: Randomized crossover design. Setting: Two level-3 university perinatal centers. Patients: 22 infants ( mean (SD): birth weight, 705 g ( 215); gestational age, 25.6 weeks ( 2.0); age at study, 22.9 days ( 15.6)). Interventions: One 4- hour period of PAV was applied on each of 2 consecutive days and compared with epochs of standard PTV. Results: Mean airway pressure was 5.64 ( SD, 0.81) cm H2O during PAV and 6.59 ( SD, 1.26) cm H2O during PTV ( p < 0.0001), the mean peak inspiratory pressure was 10.3 ( SD, 2.48) cm H2O and 15.1 ( SD, 3.64) cm H2O ( p < 0.001), respectively. The FiO(2) ( 0.34 (0.13) vs. 0.34 ( 0.14)) and pulse oximetry readings were not significantly different. The incidence of arterial oxygen desaturations was not different ( 3.48 ( 3.2) vs. 3.34 ( 3.0) episodes/ h) but desaturations lasted longer during PAV ( 2.60 ( 2.8) vs. 1.85 ( 2.2) min of desaturation/ h, p = 0.049). PaCO2 measured transcutaneously in a subgroup of 12 infants was similar. One infant met prespecified PAV failure criteria. No adverse events occurred during the 164 cumulative hours of PAV application. Conclusions: PAV safely maintains gas exchange at lower mean airway pressures compared with PTV without adverse effects in this population. Backup conventional ventilation breaths must be provided to prevent apnea-related desaturations. Copyright (c) 2007 S. Karger AG, Base

EFECTO DEL MANEJO SILVÍCOLA Y CLASE DE COPA SOBRE LA DENSIDAD BÁSICA DE Eucalyptus nitens

This research was curried out in the 8th region andean lower part in Chile and aim to analyze the effect of silvicultural management about Eucalyptus nitens basic density variation. The study was based on a 10 year-old stand which was pruned and thinned at the age of 30 months, evaluating different pruning intensity and thinning density. It was also studied, in every defined treatment, the effect produced by different types of crown on the basic density behavior. The total sample consisted on 36 trees from which 7 different discs were obtained and every one had different: trunk height, being finally calculated their basic density. The results determined that thinning affected the basic density and non-intervened stands presented a minor average basic density than those intervened; on the other hand, those plots with pruning presented the lowest average for this variable. The dominant crown presented a higher basic density than the co-dominant and suppressed one respectively. Concerning wood density in relation to the sample trunk height, this tended to increase from the buton to the tip even though it presented a small decrease in the first sections of the tree.  Para analizar el efecto del manejo silvícola sobre la variación de la densidad básica de la madera de Eucalyptus nitens, se estudió una plantación en el sector precordillerano andino de la VIII región en Chile. El estudio se realizó en un rodal de 10 años, intervenido a los 2 años y medio de establecido, evaluándose distintas intensidades de poda y densidades de raleo. En cada tratamiento definido, se estudió también el efecto de la clase de copa sobre el comportamiento de la densidad básica. Se muestreó un total de 36 árboles, obteniéndose de cada uno, siete discos a diferentes alturas del fuste, calculándose finalmente su densidad básica. Los resultados determinaron que el raleo afectó la densidad básica, presentando los rodales sin intervención, una densidad básica promedio menor que aquellos intervenidos; en cambio en aquellas unidades muestrales con poda, se presentaron los menores valores promedios para esta variable. La clase de copa dominante presentó una densidad básica superior a la codominante y suprimida respectivamente. En cuanto al comportamiento de la densidad de la madera en función de la altura de muestreo en el fuste, ésta tendió a aumentar desde la base al ápice, aunque presentó una leve disminución en las primeras secciones del árbol

Bronchopulmonary Dysplasia: Executive Summary of a Workshop

Comment in Bronchopulmonary Dysplasia: The Ongoing Search for One Definition to Rule Them All. [J Pediatr. 2018] Midlife crisis? In its 50th year, BPD redefines itself. [J Pediatr. 2018

Resuscitation of the Newborn

Immediate initiation of resuscitative measures is necessary when a newborn does not spontaneously establish normal respiration within a few seconds after delivery. To assure that these measures can be taken properly and quickly, appropriate personnel and equipment should be accessible at all times

Care of the Infant With Prolonged Ventilator Dependency

The improved survival of critically ill infants has resulted in a rapid increase in the number of patients who require prolonged respiratory support. As a result of this, neonatal and pediatric intensive care units are frequently faced with the dilemma of having to allocate a portion of their limited resources to the care of infants who remain ventilator dependent for extended periods.Despite the magnitude of this problem, it has seldom been addressed in the medical literature. This may reflect the frustration inherent in this situation for care givers who are accustomed to dealing with acute rather than chronic illnesses. The article from Schreiner and collaborators1 in this issue of The Journal describes many facets of this problem and raises several medical, ethical, and social issues.The first and most important question that needs to be considered is whether different treatment strategies for infants with acute respiratory failure can influenc