José R. M. Ramos

Lung mechanics and high-resolution computed tomography of the chest in very low birth weight premature infants

CONTEXT Premature infant lung development may be affected by lung injuries during the first few weeks of life. Lung injuries have been associated with changes in lung mechanics. OBJECTIVE To evaluate an association between lung mechanics and lung structural alterations in very low birth weight infants (birth weight less than 1500 g). DESIGN A cross-sectional evaluation of pulmonary mechanics (lung compliance and lung resistance) and high resolution computed tomography of the chest at the time of discharge, in 86 very low birth weight infants born at Instituto Fernandes Figueira, a tertiary public healthcare institution in Rio de Janeiro, Brazil. Lung compliance and resistance were measured during quiet sleep. High resolution computed tomography was performed using Pro Speed-S equipment. MAIN MEASUREMENTS Statistical analysis was performed by means of variance analysis (ANOVA/Kruskal Wallis). The significance level was set at 0.05. RESULTS Abnormal values for both lung compliance and lung resistance were found in 34 babies (43%), whereas 20 (23.3%) had normal values for both lung compliance and lung resistance. The mean lung compliance and lung resistance for the group were respectively 1.30 ml/cm H2O/kg and 63.7 cm H2O/l/s. Lung alterations were found via high-resolution computed tomography in 62 (72%) infants. Most infants showed more than one abnormality, and these were described as ground glass opacity, parenchymal bands, atelectasis and bubble/cyst. The mean compliance values for infants with normal (1.49 ml/cm H2O/kg) high resolution computed tomography, 1 or 2 abnormalities (1.31 ml/cm H2O/kg) and 3 or more abnormalities (1.16 ml/cm H2O/kg) were significantly different (p=0.015). Our data were insufficient to find any association between lung resistance and the number of alterations via high-resolution computed tomography. CONCLUSION The results show high prevalence of lung functional and tomographic abnormalities in asymptomatic very low birth weight infants at the time of discharge. They also show an association between lung morphological and functional abnormalities.

Case report: vertical dengue infection

OBJECTIVES To report a case of vertical dengue infection in a newborn from Rio de Janeiro, Brazil, and to review the literature concerning this problem. DESCRIPTION We report a case of vertical dengue infection. Female neonate, birth weight 3,940 g, term, was admitted to a neonatal intensive care unit on the fifth day of life with fever and erythematous rash. Her mother had had dengue fever 3 days before delivery. Her platelet count was 38,000, dropping to 15,000. She did not have any hemorrhagic episodes, including cerebral hemorrhages. Anti-dengue antibodies (IgM) were positive in the mother and infant. Dengue type 2 was detected in the infant using polymerase chain reaction. COMMENTS This report emphasizes that pediatricians should be aware of the possibility of vertical dengue infection so that early management can be instituted.

Incidence and main risk factors associated with extubation failure in newborns with birth weight < 1,250 grams

OBJECTIVES To determine the incidence of extubation failure in preterm newborns with birth weight < 1,250 g extubated to nasal continuous positive airway pressure and to identify the main risk factors associated with the need for reintubation in this population. METHODS A retrospective review of eligible infants admitted and mechanically ventilated between July 2002 and June 2004 was performed. Extubation failure was defined as the need for reintubation within 7 days after the first extubation attempt. RESULTS Of the 52 patients included in the study, 13 died before the first extubation attempt. Of the remaining 39 patients, only nine failed extubation (23.1%) Comparing the two groups (failure vs. successful), there was a statistically significant difference regarding birth weight, gestational age and 5-minute Apgar score. After logistic regression, only gestational age was significant. Other secondary outcomes showed significant difference between the groups: intracranial hemorrhage grade III and/or IV, patent ductus arteriosus and death. CONCLUSIONS The incidence of extubation failure in our population was similar to the rate reported in the literature. The main risk factor for extubation failure was prematurity (< or = 28 weeks). In this population of extreme preterm infants, implementation of strategies for early extubation, use of methylxanthines, prevention of patent ductus arteriosus, and use of different modes of assisted ventilation after extubation may improve the outcomes.

Neonatal risk factors for respiratory morbidity during the first year of life among premature infants

CONTEXT AND OBJECTIVE There have been dramatic increases in very low birth weight infant survival. However, respiratory morbidity remains problematic. The aim here was to verify associations between pulmonary mechanics, pulmonary structural abnormalities and respiratory morbidity during the first year of life. DESIGN AND SETTING Prospective cohort study at Instituto Fernandes Figueira, Fundação Oswaldo Cruz, Rio de Janeiro. METHODS Premature infants with birth weight < 1500 g were studied. Lung function tests and high-resolution chest tomography were performed before discharge. During the first year, infants were assessed for respiratory morbidity (obstructive airways, pneumonia or hospitalization). Neonatal lung tests and chest tomography and covariables potentially associated with respiratory morbidity were independently assessed using relative risk (RR). RR was subsequently adjusted via logistic regression. RESULTS Ninety-seven newborn infants (mean birth weight: 1113 g; mean gestational age: 28 weeks) were assessed. Lung compliance and lung resistance were abnormal in 40% and 59%. Tomography abnormalities were found in 72%; respiratory morbidity in 53%. Bivariate analysis showed respiratory morbidity associated with: mechanical ventilation, prolonged oxygen use (beyond 28 days), oxygen use at 36 weeks, respiratory distress syndrome, neonatal pneumonia and patent ductus arteriosus. Multivariate analysis gave RR 2.7 (confidence interval: 0.7-10.0) for simultaneous lung compliance and chest tomography abnormalities. Adjusted RR for neonatal pneumonia and mechanical ventilation were greater. CONCLUSIONS Upon discharge, there were high rates of lung mechanism and tomography abnormalities. More than 50% presented respiratory morbidity during the first year. Neonatal pneumonia and mechanical ventilation use were statistically significant risk factors.

Incidência e principais fatores associados à falha de extubação em recém-nascidos com peso de nascimento < 1.250 gramas

OBJECTIVES: To determine the incidence of extubation failure in preterm newborns with birth weight < 1,250 g extubated to nasal continuous positive airway pressure and to identify the main risk factors associated with the need for reintubation in this population. METHODS: A retrospective review of eligible infants admitted and mechanically ventilated between July 2002 and June 2004 was performed. Extubation failure was defined as the need for reintubation within 7 days after the first extubation attempt. RESULTS: Of the 52 patients included in the study, 13 died before the first extubation attempt. Of the remaining 39 patients, only nine failed extubation (23.1%) Comparing the two groups (failure vs. successful), there was a statistically significant difference regarding birth weight, gestational age and 5-minute Apgar score. After logistic regression, only gestational age was significant. Other secondary outcomes showed significant difference between the groups: intracranial hemorrhage grade III and/or IV, patent ductus arteriosus and death. CONCLUSIONS: The incidence of extubation failure in our population was similar to the rate reported in the literature. The main risk factor for extubation failure was prematurity (≤ 28 weeks). In this population of extreme preterm infants, implementation of strategies for early extubation, use of methylxanthines, prevention of patent ductus arteriosus, and use of different modes of assisted ventilation after extubation may improve the outcomes.

Relato de caso: transmissão vertical de dengue

OBJECTIVES: To report a case of vertical dengue infection in a newborn from Rio de Janeiro, Brazil, and to review the literature concerning this problem. DESCRIPTION: We report a case of vertical dengue infection. Female neonate, birth weight 3,940 g, term, was admitted to a neonatal intensive care unit on the fifth day of life with fever and erythematous rash. Her mother had had dengue fever 3 days before delivery. Her platelet count was 38,000, dropping to 15,000. She did not have any hemorrhagic episodes, including cerebral hemorrhages. Anti-dengue antibodies (IgM) were positive in the mother and infant. Dengue type 2 was detected in the infant using polymerase chain reaction. COMMENTS: This report emphasizes that pediatricians should be aware of the possibility of vertical dengue infection so that early management can be instituted.

Indirect calorimetry: a tool to adjust energy expenditure in very low birth weight infants

OBJECTIVE To determine the resting metabolic rate in very low birth weight infants through indirect calorimetry. METHODS Cross-sectional study including 29 clinically stable very low birth weight infants receiving an enteral diet > 100 kcal/kg/day. Malnutrition was defined as weight-for-age z score < or = - 2 SD. Resting energy expenditure was measured using open circuit indirect calorimetry. RESULTS At the time of the examination, mean weight was 1,564+/-393 g and corrected gestational age was 35+/-3 weeks. Malnutrition was diagnosed in 62.1% of the preterm infants. The mean resting metabolic rate was 57.01+/-7.76 kcal/kg/day. CONCLUSION Since resting energy expenditure is the main caloric component of total energy expenditure, the high resting metabolic rate observed may have a strong impact on the development of malnutrition during hospitalization.

Development of a technique for evaluating temporal parameters of sucking in breastfeeding preterm newborns

AIMS The aim of the current study was to developed and test the reliability of a technique for measuring temporal parameters of sucking in breastfeeding infants. METHODS The technique was developed using a cohort of 11 term and 12 preterm infants, and subsequently evaluated using a cohort of 43 preterm infants. Measurements related to sucking pressure in the term and preterm infants were acquired. The signals were recorded for 5 min, saved on a computer, and stored for analysis. For purposes of analysis, the minute with the highest quality signal was chosen. Signal analysis was performed by two researchers, and inter- and intra-observer agreement was assessed. The newborns in the sample had different gestational ages. RESULTS A technique was developed for the analysis of temporal parameters of sucking during breastfeeding and evaluated in 43 preterm infants with different gestational ages for the following variables: number of bursts per minute, number of sucks per burst, sucking rate, pause rate, and duration of pauses. The intra-observer agreement was 0.85 and the inter-observer agreement was 0.85. CONCLUSIONS The technique that was developed and validated proved capable of measuring temporal parameters of sucking in breastfeeding newborns.

Longitudinal assessment of the lung mechanics of very low birth weight preterm infants with and without bronchopulmonary dysplasia

CONTEXT AND OBJECTIVE Prematurity has been correlated with altered lung mechanics. Some infants develop lung injury as a consequence of lung immaturity, invasive mechanical ventilation and exposure to oxygen, thus resulting in bronchopulmonary dysplasia. The aim here was to compare the lung mechanics of preterm infants with and without bronchopulmonary dysplasia during the first year of life. DESIGN AND SETTING Prospective cohort study in a tertiary-level hospital. METHODS This study included premature infants at a public hospital who underwent two pulmonary function tests: one at discharge and the other at the corrected age of 4 to 8 months. Tidal volume, lung compliance and lung resistance were measured. Statistical tests were used for comparisons between infants with and without bronchopulmonary dysplasia. RESULTS 102 children with mean gestational age of 29 ± 2.0 weeks were studied; 17 with bronchopulmonary dysplasia. Lung compliance (0.84 ± 0.29 versus 1.28 ± 0.46; P < 0.001) and tidal volume (6.1 ± 0.94 versus 7.2 ± 1.43; P < 0.01) at discharge were significant lower in children with bronchopulmonary dysplasia than in those without the disease, but no differences were observed at the second test (compliance: 1.53 ± 0.77 versus 1.94 ± 1.01; P = 0.12; and tidal volume: 6.9 ± 1.4 versus 7.3 ± 1.6; P = 0.42). CONCLUSION Differences in lung mechanics were observed between infants with and without bronchopulmonary dysplasia at hospital discharge but these differences were no longer detected at the final follow-up. The lung mechanics of all the infants improved over this period of time.

High Resolution CT Scan and Pulmonary Function Studies in the Very Low Birth Weight Infant before Discharge

High Resolution CT Scan and Pulmonary Function Studies in the Very Low Birth Weight Infant before Discharge