High-flow nasal cannula failure: can clinical outcomes determine early interruption?

OBJECTIVE: To evaluate the evolution of clinical outcomes in children with bronchiolitis who used a high-flow nasal cannula, and to determine after long of non-clinical improvement the therapy should be discontinued, and treatment should be escalated to other forms of ventilatory support. METHODS: An observational retrospective study of infants with bronchiolitis who used a high-flow nasal cannula. Patients were divided into two study groups according to success or failure of high-flow nasal cannula therapy, namely the Success Group and the Failure Group. The main demographics and clinical variables were assessed 30 minutes and 6 hours after initiating therapy until removal of the high-flow nasal cannula. RESULTS: A total of 83 children were studied and 18 children (21.7%) failed therapy. Among subjects with successful therapy, a significant decrease in respiratory rate (p<0.001), and a significant increase in peripheral oxygen saturation (p<0.001) were observed within 30 minutes. The Success Group was significantly different from the Failure Group after 6 hours, for both respiratory rate (p<0.01) and peripheral oxygen saturation (p<0.01). CONCLUSION: The absence of clinical sign improvement within 30 minutes and for up to a maximum of 6 hours can be considered as failure of the high-flow nasal cannula therapy. If this time elapses with no improvements, escalating to another type of ventilatory support should be considered.

Primary Ciliary Dyskinesia as a Cause of Repeating Atelectasis in the Neonatal Period.

BACKGROUND Primary ciliary dyskinesia (PCD) is a disease characterized by motor ciliary dysfunction, which leads to the accumulation of secretions in the lower airways and, consequently, to atelectasis and repeated infections. During the neonatal period, diagnosis can be difficult because the symptoms are frequently associated with other respiratory diseases common in neonates. The laterality defects should warn the clinician of the need for further investigation using clinical criteria, but the confirmation depends on a genetic test. CASE REPORT The objective of this report is to present a case of PCD manifesting in the neonatal period that was diagnosed due to respiratory failure associated with recurrent atelectasis and situs inversus totalis. CONCLUSIONS This disease is not well known by neonatologists, but early diagnosis decreases morbidity and improves patient quality of life.

Polyethylene glycol addition does not improve exogenous surfactant function in an experimental model of meconium aspiration syndrome.

Meconium (MEC) is a potent inactivator of pulmonary surfactant. The authors studied the effects of polyethylene glycol addition to the exogenous surfactant over the lung mechanics and volumes. Human meconium was administrated to newborn rabbits. Animals were ventilated for 20 minutes and dynamic compliance, ventilatory pressure, and tidal volume were recorded. Animals were randomized into 3 study groups: MEC group (without surfactant therapy); S100 group (100 mg/kg surfactant); and PEG group (100 mg/kg porcine surfactant plus 5% PEG). After ventilation, a pulmonary pressure-volume curve was built. Histological analysis was carried out to calculate the mean alveolar size (Lm) and the distortion index (DI). Both groups treated with surfactant showed higher values of dynamic pulmonary compliance and lower ventilatory pressure, compared with the MEC group (P < .05). S100 group had a larger maximum lung volume, V(30), compared with the MEC group (P < .05). Lm and DI values were smaller in the groups treated with surfactant than in the MEC group (P < .05). No differences were observed between the S100 and PEG groups. Animals treated with surfactant showed significant improvement in pulmonary function as compared to nontreated animals. PEG added to exogenous surfactant did not improve lung mechanics or volumes.

Spontaneous breathing test in the prediction of extubation failure in the pediatric population.

OBJECTIVE: To assess whether the spontaneous breathing test can predict the extubation failure in pediatric population. METHODS: A prospective and observational study that evaluated data of inpatients at the Pediatric Intensive Care Unit between May 2011 and August 2013, receiving mechanical ventilation for at least 24 hours followed by extubation. The patients were classified in two groups: Test Group, with patients extubated after spontaneous breathing test, and Control Group, with patients extubated without spontaneous breathing test. RESULTS: A total of 95 children were enrolled in the study, 71 in the Test Group and 24 in the Control Group. A direct comparison was made between the two groups regarding sex, age, mechanical ventilation time, indication to start mechanical ventilation and respiratory parameters before extubation in the Control Group, and before the spontaneous breathing test in the Test Group. There was no difference between the parameters evaluated. According to the analysis of probability of extubation failure between the two groups, the likelihood of extubation failure in the Control Group was 1,412 higher than in the Test Group, nevertheless, this range did not reach significance (p=0.706). This model was considered well-adjusted according to the Hosmer-Lemeshow test (p=0.758). CONCLUSION: The spontaneous breathing test was not able to predict the extubation failure in pediatric population. OBJETIVO: Avaliar se o teste de respiração espontânea pode ser utilizado para predizer falha da extubação na população pediátrica. MÉTODOS: Estudo prospectivo, observacional, no qual foram avaliados todos os pacientes internados no Centro de Terapia Intensiva Pediátrica, no período de maio de 2011 a agosto de 2013, que utilizaram ventilação mecânica por mais de 24 horas e que foram extubados. Os pacientes foram classificados em dois grupos: Grupo Teste, que incluiu os pacientes extubados depois do teste de respiração espontânea; e Grupo Controle, pacientes foram sem teste de respiração espontânea. RESULTADOS: Dos 95 pacientes incluídos no estudo, 71 crianças eram do Grupo Teste e 24 eram do Grupo Controle. Os grupos foram comparados em relação a: sexo, idade, tempo de ventilação mecânica, indicação para início da ventilação mecânica e parâmetros ventilatórios pré-extubação, no Grupo Controle, e pré-realização do teste, no Grupo Teste. Não foram observadas diferenças entre os parâmetros analisados. Em relação à análise da probabilidade de falha da extubação entre os dois grupos de estudo, a chance de falha do Grupo Controle foi 1.412 maior do que a das crianças do Grupo Teste, porém este acréscimo não foi significativo (p=0,706). O modelo foi considerado bem ajustado de acordo com o teste de Hosmer-Lemeshow (p=0,758). CONCLUSÃO: O teste de respiração espontânea para a população pediátrica não foi capaz de prever a falha da extubação.

Manual Ventilation and Sustained Lung Inflation in an Experimental Model: Influence of Equipment Type and Operator's Training.

AIM: To compare the influence of devices for manual ventilation and individual experience on the applied respiratory mechanics and sustained lung inflation. METHODS: A total of 114 instructors and non-instructors from the Neonatal Resuscitation Program of the Brazilian Society of Pediatrics participated in this study. Participants ventilated an intubated manikin. To evaluate respiratory mechanics and sustained lung inflation parameters, a direct comparison was made between the self-inflating bag and the T-shaped resuscitator (T-piece), followed by an analysis of the effectiveness of the equipment according to the participants' education and training. RESULTS: A difference between equipment types was observed for the tidal volume, with a median (interquartile range) of 28.5 mL (12.6) for the self-inflating bag and 20.1 mL (8.4) for the T-piece in the instructor group and 31.6 mL (14) for the self-inflating bag and 22.3 mL (8.8) for the T-piece in the non-instructor group. Higher inspiratory time values were observed with the T-piece in both groups of professionals, with no significant difference between them. The operator's ability to maintain the target pressure over the 10 seconds of sustained lung inflation was evaluated using the area under the pressure-time curve and was 1.7-fold higher with the use of the T-piece. Inspiratory pressure and mean airway pressure applied during sustained lung inflation were greater with the self-inflating bag, as evaluated between the beginning and the end of the procedure. CONCLUSION: The T-piece resulted in lower tidal volume and higher inspiratory time values, irrespective of the operator's experience, and increased the ease of performing the sustained lung inflation maneuver, as demonstrated by the maintenance of target pressure for the desired period and a higher mean airway pressure than that obtained using the self-inflating bag.

High-flow nasal cannula failure: can clinical outcomes determine early interruption? / Falha da cânula nasal de alto fluxo: os desfechos clínicos podem determinar a interrupção precoce?

ABSTRACT Objective: To evaluate the evolution of clinical outcomes in children with bronchiolitis who used a high-flow nasal cannula, and to determine after long of non-clinical improvement the therapy should be discontinued, and treatment should be escalated to other forms of ventilatory support. Methods: An observational retrospective study of infants with bronchiolitis who used a high-flow nasal cannula. Patients were divided into two study groups according to success or failure of high-flow nasal cannula therapy, namely the Success Group and the Failure Group. The main demographics and clinical variables were assessed 30 minutes and 6 hours after initiating therapy until removal of the high-flow nasal cannula. Results: A total of 83 children were studied and 18 children (21.7%) failed therapy. Among subjects with successful therapy, a significant decrease in respiratory rate (p<0.001), and a significant increase in peripheral oxygen saturation (p<0.001) were observed within 30 minutes. The Success Group was significantly different from the Failure Group after 6 hours, for both respiratory rate (p<0.01) and peripheral oxygen saturation (p<0.01). Conclusion: The absence of clinical sign improvement within 30 minutes and for up to a maximum of 6 hours can be considered as failure of the high-flow nasal cannula therapy. If this time elapses with no improvements, escalating to another type of ventilatory support should be considered.

RESUMO Objetivo: Avaliar a evolução de desfechos clínicos em crianças com bronquiolite que utilizaram cânula nasal de alto fluxo, e determinar com quanto tempo de não melhora clínica a terapia deve ser interrompida para escalonamento do tratamento para outras formas de suporte ventilatório. Métodos: Estudo observacional retrospectivo, de lactentes com bronquiolite que utilizaram cânula nasal de alto fluxo. Os pacientes foram divididos em dois grupos de estudo, de acordo com o sucesso ou não da terapêutica com cânula nasal de alto fluxo, nomeados Grupo Sucesso e Grupo Falha. Foram analisadas as principais características demográficas e variáveis clínicas, tendo sido avaliadas 30 minutos e 6 horas após o início do tratamento até a retirada da cânula nasal de alto fluxo. Resultados: Foram estudados 83 crianças; destas, 18 crianças (21,7%) falharam. Entre os pacientes que tiveram sucesso na terapia, observou-se diminuição significativa da frequência respiratória (p<0,001), e também aumento significativo da saturação de oxigênio (p<0,001) já nos primeiros 30 minutos. O Grupo Sucesso foi significativamente diferente do Grupo Falha a partir de 6 horas, tanto para frequência respiratória (p<0,01), quanto para saturação de oxigênio (p<0,01). Conclusão: Na ausência de melhora dos sinais clínicos, a falha da terapia com cânula nasal de alto fluxo já pode ser considerada a partir de 30 minutos e, no máximo, em até 6 horas após o início da terapia. Após esse período sem melhora, o escalonamento para outro tipo de suporte ventilatório deve ser avaliado.

A multicenter, randomized, double-blind trial of a new porcine surfactant in premature infants with respiratory distress syndrome.

OBJECTIVE: To compare the efficacy and safety of a new porcine-derived pulmonary surfactant developed by Instituto Butantan with those of animal-derived surfactants commercially available in Brazil, regarding neonatal mortality and the major complications of prematurity in preterm newborns with birth weight up to 1500g and diagnosed with respiratory distress syndrome. METHODS: Neonates diagnosed with respiratory distress syndrome were randomized to receive either Butantan surfactant (Butantan group) or one of the following surfactants: Survanta® or Curosurf®. Newborns receiving Survanta® or Curosurf® comprised the control group. The main outcome measures were mortality rates at 72 hours and at 28 days of life; the typical complications of prematurity as evaluated on the 28th day of life were defined as secundary outcomes. RESULTS: No differences were observed between the Butantan (n=154) and control (n=173) groups in relation to birth weight, gestational age, sex, and prenatal use of corticosteroids, or in mortality rates both at 72 hours (14.19% versus 14.12%; p=0.98) and at 28 days (39.86% versus 33.33%; p=0.24) of life. Higher 1- and 5-minute Apgar scores were observed among control group newborns. No differences were observed as regards the secondary outcomes, except for greater need for supplemental oxygen and a higher incidence of interstitial pulmonary emphysema in the Butantan group. CONCLUSION: The mortality rates at 72 hours and 28 days of life and the incidence of major complications of prematurity were comparable to those found with the animal-derived surfactants commercially available in Brazil, showing the efficacy and safety of the new surfactant in the treatment of respiratory distress syndrome in newborns.

A hyperoxic lung injury model in premature rabbits: the influence of different gestational ages and oxygen concentrations.

BACKGROUND: Many animal models have been developed to study bronchopulmonary dysplasia (BPD). The preterm rabbit is a low-cost, easy-to-handle model, but it has a high mortality rate in response to the high oxygen concentrations used to induce lung injury. The aim of this study was to compare the mortality rates of two models of hyperoxia-induced lung injury in preterm rabbits. METHODS: Pregnant New Zealand white rabbits were subjected to caesarean section on gestational day 28 or 29 (full term  = 31 days). The premature rabbits in the 28-day gestation group were exposed to room air or FiO2 ≥95%, and the rabbits in the 29-day gestation group were exposed to room air or FiO2  = 80% for 11 days. The mean linear intercept (Lm), internal surface area (ISA), number of alveoli, septal thickness and proportion of elastic and collagen fibers were quantified. RESULTS: The survival rates in the 29-day groups were improved compared with the 28-day groups. Hyperoxia impaired the normal development of the lung, as demonstrated by an increase in the Lm, the septal thickness and the proportion of elastic fibers. Hyperoxia also decreased the ISA, the number of alveoli and the proportion of collagen fibers in the 28-day oxygen-exposed group compared with the control 28-day group. A reduced number of alveoli was found in the 29-day oxygen exposed animals compared with the control 29-day group. CONCLUSIONS: The 29-day preterm rabbits had a reduced mortality rate compared with the 28-day preterm rabbits and maintained a reduction in the alveoli number, which is comparable to BPD in humans.

Influence of assessment site in measuring transcutaneous bilirubin.

OBJECTIVE: To investigate the influence of the site of measurement of transcutaneous bilirubin (forehead or sternum) in reproducibility of results as compared to plasma bilirubin. METHODS: A cohort study including 58 term newborns with no hemolytic disease. Transcutaneous measurements were performed on the forehead (halfway between the headline and the glabella, from the left toward the right side, making consecutive determinations, one-centimeter apart) and the sternum (five measurements, from the suprasternal notch to the xiphoid process with consecutive determinations, one-centimeter apart) using Bilicheck® (SpectRx Inc, Norcross, Georgia, USA). The correlation and agreement between both methods and plasma bilirubin were calculated. RESULTS: There was a strong linear correlation between both determinations of serum bilirubin at the forehead and sternum (r=0.704; p<0.01 and r=0.653; p<0.01, respectively). There was correspondence of the mean values of transcutaneous bilirubin measured on the sternum (9.9 ± 2.2mg/dL) compared to plasma levels (10.2 ± 1.7 mg/dL), but both differ from the values measured on the forehead (8.6 ± 2 .0mg/dL), p<0.05. CONCLUSION: In newborn term infants with no hemolytic disease, measuring of transcutaneous bilirubin on the sternum had higher accuracy as compared to serum bilirubin measurement on the forehead.

Electrical impedance tomography to evaluate air distribution prior to extubation in very-low-birth-weight infants: a feasibility study.

OBJECTIVES: Nasal continuous positive airway pressure is used as a standard of care after extubation in very-low-birth-weight infants. A pressure of 5 cmH2O is usually applied regardless of individual differences in lung compliance. Current methods for evaluation of lung compliance and air distribution in the lungs are thus imprecise for preterm infants. This study used electrical impedance tomography to determine the feasibility of evaluating the positive end-expiratory pressure level associated with a more homogeneous air distribution within the lungs before extubation. METHODS: Ventilation homogeneity was defined by electrical impedance tomography as the ratio of ventilation between dependent and non-dependent lung areas. The best ventilation homogeneity was achieved when this ratio was equal to 1. Just before extubation, decremental expiratory pressure levels were applied (8, 7, 6 and 5 cmH(2)0; 3 minutes each step), and the pressure that determined the best ventilation homogeneity was defined as the best positive end-expiratory pressure. RESULTS: The best positive end-expiratory pressure value was 6.3 ± 1.1 cmH(2)0, and the mean continuous positive airway pressure applied after extubation was 5.2 ± 0.4 cmH(2)0 (p = 0.002). The extubation failure rate was 21.4%. X-Ray and blood gases after extubation were also checked. CONCLUSION: This study demonstrates that electrical impedance tomography can be safely and successfully used in patients ready for extubation to suggest the best ventilation homogeneity, which is influenced by the level of expiratory pressure applied. In this feasibility study, the best lung compliance was found with pressure levels higher than the continuous positive airway pressure levels that are usually applied for routine extubation.

Improvement in ARDS experimental model installation: low mortality rate and maintenance of hemodynamic stability.

INTRODUCTION: Many experimental models using lung lavage have been developed for the study of acute respiratory distress syndrome (ARDS). The original technique has been modified by many authors, resulting in difficulties with reproducibility. There is insufficient detail on the lung injury models used, including hemodynamic stability during animal preparation and drawbacks encountered such as mortality. The authors studied the effects of the pulmonary recruitment and the use of fixed tidal volume (Vt) or fixed inspiratory pressure in the experimental ARDS model installation. METHODS: Adult rabbits were submitted to repeated lung lavages with 30 ml/kg warm saline until the ARDS definition (PaO2/FiO2 ≤ 100) was reached. The animals were divided into three groups, according to the technique used for mechanical ventilation: 1) fixed Vt of 10 ml/kg; 2) fixed inspiratory pressure (IP) with a tidal volume of 10 ml/kg prior to the first lung lavage; and 3) fixed Vt of 10 ml/kg with pulmonary recruitment before the first lavage. RESULTS: The use of alveolar recruitment maneuvers, and the use of a fixed Vt or IP between the lung lavages did not change the number of lung lavages necessary to obtain the experimental model of ARDS or the hemodynamic stability of the animals during the procedure. A trend was observed toward an increased mortality rate with the recruitment maneuver and with the use of a fixed IP. DISCUSSION: There were no differences between the three study groups, with no disadvantage in method of lung recruitment, either fixed tidal volume or fixed inspiratory pressure, regarding the number of lung lavages necessary to obtain the ARDS animal model. Furthermore, the three different procedures resulted in good hemodynamic stability of the animals, and low mortality rate.

Spontaneous breathing test in the prediction of extubation failure in the pediatric population / Teste de respiração espontânea na previsão de falha de extubação em população pediátrica

ABSTRACT Objective To assess whether the spontaneous breathing test can predict the extubation failure in pediatric population. Methods A prospective and observational study that evaluated data of inpatients at the Pediatric Intensive Care Unit between May 2011 and August 2013, receiving mechanical ventilation for at least 24 hours followed by extubation. The patients were classified in two groups: Test Group, with patients extubated after spontaneous breathing test, and Control Group, with patients extubated without spontaneous breathing test. Results A total of 95 children were enrolled in the study, 71 in the Test Group and 24 in the Control Group. A direct comparison was made between the two groups regarding sex, age, mechanical ventilation time, indication to start mechanical ventilation and respiratory parameters before extubation in the Control Group, and before the spontaneous breathing test in the Test Group. There was no difference between the parameters evaluated. According to the analysis of probability of extubation failure between the two groups, the likelihood of extubation failure in the Control Group was 1,412 higher than in the Test Group, nevertheless, this range did not reach significance (p=0.706). This model was considered well-adjusted according to the Hosmer-Lemeshow test (p=0.758). Conclusion The spontaneous breathing test was not able to predict the extubation failure in pediatric population.

RESUMO Objetivo Avaliar se o teste de respiração espontânea pode ser utilizado para predizer falha da extubação na população pediátrica. Métodos Estudo prospectivo, observacional, no qual foram avaliados todos os pacientes internados no Centro de Terapia Intensiva Pediátrica, no período de maio de 2011 a agosto de 2013, que utilizaram ventilação mecânica por mais de 24 horas e que foram extubados. Os pacientes foram classificados em dois grupos: Grupo Teste, que incluiu os pacientes extubados depois do teste de respiração espontânea; e Grupo Controle, pacientes foram sem teste de respiração espontânea. Resultados Dos 95 pacientes incluídos no estudo, 71 crianças eram do Grupo Teste e 24 eram do Grupo Controle. Os grupos foram comparados em relação a: sexo, idade, tempo de ventilação mecânica, indicação para início da ventilação mecânica e parâmetros ventilatórios pré-extubação, no Grupo Controle, e pré-realização do teste, no Grupo Teste. Não foram observadas diferenças entre os parâmetros analisados. Em relação à análise da probabilidade de falha da extubação entre os dois grupos de estudo, a chance de falha do Grupo Controle foi 1.412 maior do que a das crianças do Grupo Teste, porém este acréscimo não foi significativo (p=0,706). O modelo foi considerado bem ajustado de acordo com o teste de Hosmer-Lemeshow (p=0,758). Conclusão O teste de respiração espontânea para a população pediátrica não foi capaz de prever a falha da extubação.

Bubble CPAP versus CPAP with variable flow in newborns with respiratory distress: a randomized controlled trial.

OBJECTIVE: To evaluate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) using devices with variable flow or bubble continuous positive airway pressure (CPAP) regarding CPAP failure, presence of air leaks, total CPAP and oxygen time, and length of intensive care unit and hospital stay in neonates with moderate respiratory distress (RD) and birth weight (BW) ≥ 1,500 g. METHODS: Forty newborns requiring NCPAP were randomized into two study groups: variable flow group (VF) and continuous flow group (CF). The study was conducted between October 2008 and April 2010. Demographic data, CPAP failure, presence of air leaks, and total CPAP and oxygen time were recorded. Categorical outcomes were tested using the chi-square test or the Fisher's exact test. Continuous variables were analyzed using the Mann-Whitney test. The level of significance was set at p < 0.05. RESULTS: There were no differences between the groups with regard to demographic data, CPAP failure (21.1 and 20.0% for VF and CF, respectively; p = 1.000), air leak syndrome (10.5 and 5.0%, respectively; p = 0.605), total CPAP time (median: 22.0 h, interquartile range [IQR]: 8.00-31.00 h and median: 22.0 h, IQR: 6.00-32.00 h, respectively; p = 0.822), and total oxygen time (median: 24.00 h, IQR: 7.00-85.00 h and median: 21.00 h, IQR: 9.50-66.75 h, respectively; p = 0.779). CONCLUSION: In newborns with BW ≥ 1,500 g and moderate RD, the use of continuous flow NCPAP showed the same benefits as the use of variable flow NCPAP.

Timing of initial surfactant treatment in very low birth weight newborns.

OBJECTIVE: To correlate the timing of treatment using exogenous surfactant with the main variables related to respiratory distress syndrome or prematurity. METHODS: A historic cohort study between January 1, 2004 and June 30, 2007, including very low birth weight newborns (birth weight <1,500 g) admitted to the hospital and who required surfactant therapy. Newborns were divided into three study groups: early (treatment during the first two hours); intermediate (treatment between two and six hours) and late (treatment after six hours). Variables analyzed were: air leak syndrome, mortality, bronchopulmonary dysplasia, intracranial hemorrhage, patent ductus arteriosus, retinopathy of prematurity, duration of oxygen therapy, duration of mechanical ventilation, length of hospital stay and number of surfactant doses. RESULTS: A total of 63 newborns were included (Early Group, n = 21; Intermediate Group, n = 26 and Late Group, n = 16), there was a statistical significance between birth weight and gestational age. Multivariate logistic regression analysis was used to compensate the effects of gestational age, birth weight and other possible interferences over the variables. This analysis revealed a greater incidence of air leak syndrome among newborns of the Early Group compared to the Intermediate Group (OR = 6.98; 95%CI = 1.24-39.37; p = 0.028), with no difference compared to the Late Group (OR = 3.72; 95% CI = 0.28-49.76; p = 0.321). There were no differences regarding the other variables analyzed. CONCLUSIONS: In this retrospective, non-randomized study, surfactant administration during the first two hours of life enhanced the risk of air leak syndrome, compared to the treatment between two and six hours after birth, with no reduction of early or late neonatal mortality or bronchopulmonary dysplasia, compared to later treatment after birth.

High-frequency oscillatory ventilation in pediatrics and neonatology. / Ventilação oscilatória de alta freqüência em pediatria e neonatologia.

This article intends to review literature on high frequency oscillatory ventilation and describe its main clinical applications for children and neonates. Articles from the last 15 years were selected using MedLine and SciElo databases. The following key words were used: high frequency oscillatory ventilation, mechanical ventilation, acute respiratory distress syndrome, children, and new-born. The review describes high frequency oscillatory ventilation in children with acute respiratory distress syndrome, air leak syndrome, and obstructive lung disease. Respiratory distress syndrome, bronchopulmonary dysplasia, intracranial hemorrhage, periventricular leukomalacia, and air leak syndrome were reviewed in neonates. Transition from conventional mechanical ventilation to high frequency ventilation and its adjustments relating to oxygenation, CO2 elimination, chest radiography, suctioning, sedatives and use of neuromuscular blocking agents were described. Weaning and complications were also reported. For children, high frequency oscillatory ventilation is a therapeutic option, particularly in acute respiratory distress syndrome, and should be used as early as possible. It may be also useful in the air leak syndrome and obstructive pulmonary disease. Evidence that, in neonates, high frequency oscillatory ventilation is superior to conventional mechanical ventilation is lacking. However there is evidence that better results are only achieved with this ventilatory mode to manage the air leak syndrome.

Lung morphometry, collagen and elastin content: changes after hyperoxic exposure in preterm rabbits.

INTRODUCTION: Elastic and collagen fiber deposition increases throughout normal lung development, and this fiber network significantly changes when development of the lung is disturbed. In preterm rats and lambs, prolonged hyperoxic exposure is associated with impaired alveolarization and causes significant changes in the deposition and structure of elastic fibers. OBJECTIVES: To evaluate the effects of hyperoxic exposure on elastic and collagen fiber deposition in the lung interstitial matrix and in alveolarization in preterm rabbits. METHODS: After c-section, 28-day preterm New-Zealand-White rabbits were randomized into 2 study groups, according to the oxygen exposure, namely: Room air (oxygen = 21%) or Oxygen (oxygen > or = 95%). The animals were killed on day 11 and their lungs were analyzed for the alveolar size (Lm), the internal surface area (ISA), the alveoli number, and the density and distribution of collagen and elastic fibers. RESULTS: An increase in the Lm and a decrease in the alveoli number were observed among rabbits that were exposed to hyperoxia with no differences regarding the ISA. No difference in the density of elastic fibers was observed after oxygen exposure, however there were fewer collagen fibers and an evident disorganization of fiber deposition. DISCUSSION: This model reproduces anatomo-pathological injuries representing the arrest of normal alveolar development and lung architecture disorganization by just a prolonged exposition to oxygen. CONCLUSIONS: In the preterm rabbit, prolonged oxygen exposure impaired alveolarization and also lowered the proportion of collagen fibers, with an evident fiber network disorganization.

A multicenter, randomized, double-blind trial of a new porcine surfactant in premature infants with respiratory distress syndrome / Ensaio clínico multicêntrico duplo-cego randomizado com um novo surfactante de origem porcina em prematuros com síndrome do desconforto respiratório

Objective To compare the efficacy and safety of a new porcine-derived pulmonary surfactant developed by Instituto Butantan with those of animal-derived surfactants commercially available in Brazil, regarding neonatal mortality and the major complications of prematurity in preterm newborns with birth weight up to 1500g and diagnosed with respiratory distress syndrome. Methods Neonates diagnosed with respiratory distress syndrome were randomized to receive either Butantan surfactant (Butantan group) or one of the following surfactants: Survanta® or Curosurf®. Newborns receiving Survanta® or Curosurf® comprised the control group. The main outcome measures were mortality rates at 72 hours and at 28 days of life; the typical complications of prematurity as evaluated on the 28th day of life were defined as secundary outcomes. Results No differences were observed between the Butantan (n=154) and control (n=173) groups in relation to birth weight, gestational age, sex, and prenatal use of corticosteroids, or in mortality rates both at 72 hours (14.19% versus 14.12%; p=0.98) and at 28 days (39.86% versus 33.33%; p=0.24) of life. Higher 1- and 5-minute Apgar scores were observed among control group newborns. No differences were observed as regards the secondary outcomes, except for greater need for supplemental oxygen and a higher incidence of interstitial pulmonary emphysema in the Butantan group. Conclusion The mortality rates at 72 hours and 28 days of life and the incidence of major complications of prematurity were comparable to those found with the animal-derived surfactants commercially available in Brazil, showing the efficacy and safety of the new surfactant in the treatment of respiratory distress syndrome ...

Objetivo Comparar a eficácia e a segurança de um novo surfactante pulmonar de origem porcina, desenvolvido pelo Instituto Butantan, com os surfactantes de origem animal disponíveis no país, em relação à mortalidade neonatal e às principais complicações da prematuridade, em prematuros com peso de nascimento até 1500g e diagnóstico de síndrome do desconforto respiratório. Métodos Recém-nascidos com diagnóstico de síndrome do desconforto respiratório foram randomizados para receber surfactante Butantan (Grupo Butantan) ou um dos seguintes surfactantes: Survanta® ou Curosurf®. Os recém-nascidos que receberam Survanta® ou Curosurf® formaram o Grupo Controle. Foram definidas, como variáveis primárias, as mortalidades com 72 horas e 28 dias de vida e, como variáveis secundárias, as principais complicações típicas da prematuridade, avaliadas no 28O dia de vida. Resultados Não foram observadas diferenças em relação ao peso de nascimento, idade gestacional, sexo e corticoide pré-natal, assim como em relação à mortalidade dos recém-nascidos dos Grupos Butantan (n=154) e Controle (n=173), tanto com 72 horas (14,19% versus 14,12%; p=0,98) como em 28 dias de vida (39,86% versus 33,33%; p=0,24). Foram observados maiores valores do boletim de Apgar de 1 e de 5 minutos entre os recém-nascidos do Grupo Controle. Os grupos não diferiram em relação às variáveis secundárias, exceto por uma maior necessidade de uso de oxigênio e de enfisema pulmonar intersticial no Grupo Butantan. Conclusão As taxas de mortalidade com 72 horas ...