Uso convencional de surfactante en recién nacidos con enfermedad de membrana hialina / Conventional use of surfactant in newborns with hyaline membrane disease

La enfermedad de membrana hialina se debe a la deficiencia de surfactante en los pulmones de los recién nacidos especialmente los menores de 37 semanas de gestación. El manejo materno con corticoides prenatales en este grupo, disminuye la morbimortalidad asociada a esta patología neonatal. Se analiza desde el punto de la evidencia actualmente existente la administración de surfactante a estos prematuros y se revisa el tipo de surfactante a administrar, cuando es el mejor momento para administrarlo, la dosis y la forma de administrarlo.

Hyaline membrane disease is due to surfactant deficiency in the lungs of newborns, especially those younger than 37 weeks gestation. Maternal management with prenatal corticosteroids in this group reduces the morbidity and mortality associated with this neonatal pathology. The administration of surfactant to these preterm infants is analyzed from the point of the currently existing evidence and the type of surfactant to be administered is reviewed, when is the best time to administer it, the dose and the form of administration.

Presión positiva continua en la vía aérea comparada con la respiración mecánica asistida en prematuros de 28 a 32 semanas de gestación con administración precoz de surfactante pulmonar / Nasal CPAP versus mechanical ventilation in 28 to 32-week preterm infants with early surfactant administration

Introducción. La presión positiva continua en la vía aérea ( Continuous Positive Airway Pressure , CPAP) es útil en prematuros de 28 a 32 semanas de gestación con síndrome de dificultad respiratoria, pero no se ha precisado si es mejor que la respiración mecánica asistida después de la administración precoz de surfactante pulmonar. Objetivo. Comparar la incidencia de eventos adversos en prematuros de 28 a 32 semanas de gestación con síndrome de dificultad respiratoria atendidos con surfactante y respiración mecánica asistida o CPAP de burbuja. Materiales y métodos. Se atendieron 147 neonatos con respiración mecánica asistida y 176 con CPAP, ninguno de los cuales presentaba asfixia perinatal o apnea. Resultados. La incidencia de fracaso de la CPAP fue de 6,5 % (IC 95% 11,3-22,8 %). Fallecieron 29 pacientes, 7 de los cuales habían recibido CPAP (4,0 %) y, 22, respiración mecánica asistida (15,0 %; p<0,001). El riesgo relativo (RR) de morir de quienes recibieron CPAP, comparado con el de quienes recibieron respiración mecánica asistida, fue de 0,27 (IC 95% 0,12-0,61), pero, al ajustar por los factores de confusión, el uso de CPAP no implicó mayor riesgo de morir (RR=0,60; IC 95% 0,29-1,24). La letalidad con respiración mecánica asistida fue de 5,70 (IC 95% 3,75-8,66) muertes por 1.000 días-paciente, mientras que con CPAP fue de 1,37 (IC 95% 0,65-2,88; p<0,001). La incidencia de neumopatía crónica fue menor con CPAP (RR=0,71, IC 95% 0,54-0,96), al igual que la de hemorragia cerebral (RR=0,28; IC 95% 0,09-0,84) y la de sepsis (RR=0,67; IC 95% 0,52-0,86), pero fue similar en cuanto a escapes de aire (RR=2,51; IC 95% 0,83-7,61) y enterocolitis necrosante (RR=1,68; IC 95% 0,59-4,81). Conclusión. La incidencia de neumopatía crónica, hemorragia ventricular y sepsis es menor con el uso de CPAP.

Introduction: Continuous positive airway pressure (CPAP) is useful in low birth weight infants with respiratory distress, but it is not known if it is a better alternative to mechanical ventilation after early pulmonary surfactant administration. Objective: To compare the incidence of adverse events in 28 to 32-week newborns with respiratory distress managed with mechanical ventilation or CPAP after early surfactant administration. Materials and methods: In total, 176 newborns were treated with CPAP and 147 with mechanical ventilation, all with Apgar scores >3 at five minutes and without apnea. Results: The incidence of CPAP failure was 6.5% (95% CI: 11.3-22.8%); 29 patients died: 7 with CPAP (4.0%) and 22 with mechanical ventilation (15.0%, p<0.001). The relative risk of dying with CPAP versus mechanical ventilation was 0.27 (95% CI: 0.12-0.61), but after adjusting for confounding factors, CPAP use did not imply a higher risk of dying (RR=0.60; 95% CI: 0.29-1.24). Mechanical ventilation fatality rate was 5.70 (95% CI: 3.75-8.66) deaths/1,000 days-patient, while with CPAP it was 1.37 (95% CI: 0.65-2.88, p<0.001). Chronic lung disease incidence was lower with CPAP than with mechanical ventilation (RR=0.71; 95% CI: 0.54-0.96), as were intracranial hemorrhage (RR=0.28, 95% CI: 0.09-0.84) and sepsis (RR=0.67; 95%CI: 0.52-0.86), and it was similar for air leaks (RR=2.51; 95% CI: 0.83-7.61) and necrotizing enterocolitis (RR=1.68, 95% CI: 0.59-4.81). Conclusion: CPAP exposure of premature infants with respiratory distress syndrome is protective against chronic lung disease, intraventricular hemorrhage and sepsis compared to mechanical ventilation. No differences were observed regarding air leak syndrome or death.

Eficacia de tres tipos de surfactante exógeno en prematuros con enfermedad de membrana hialina / Effectiveness of three types of exogenous surfactant in preterm infants with hyaline membrane disease

Introducción: La enfermedad de membrana hialina es causa importante de mortalidad neonatal. El objetivo de esta investigación fue evaluar la eficacia de tres tipos de surfactante exógeno en prematuros. Pacientes y Método: Estudio de cohorte retrospectiva, en 93 neonatos prematuros, > 24 semanas y > 500 g de peso al nacer, 31 para cada surfactante. La exposición fue la administración de 1ª dosis bovactant (Alveofact®) 50 mg/kg, beractant (Survanta®) 100 mg/kg inicial, y poractant alfa (Curosurf®) 200 mg/kg. Las variables en estudio incluyeron tiempo de ventilación mecánica, tiempo de oxigenoterapia, estancia hospitalaria, necesidad de segunda dosis de surfactante, eventos adversos por la administración del surfactante y complicaciones por prematuridad. Además, se evaluó mortalidad, displasia broncopulmonar (DBP) y mortalidad o DBP. Análisis estadístico mediante Stata® 11.0, empleando X² o Prueba Exacta de Fisher para variables cualitativas y Pruebas ANOVA o Kruskal-Wallis para cuantitativas y riesgo relativo para las asociaciones, todas con su intervalo de confianza de 95%. Resultados: No hubo diferencias para sexo, peso y edad gestacional al nacer entre los 3 grupos. No se hallaron diferencias estadísticamente significativas para tiempo de ventilación mecánica, tiempo de oxigenoterapia, administración de una segunda dosis de surfactante, estancia hospitalaria y complicaciones entre los 3 grupos. Los eventos adversos por administración de surfactante se presentaron para beractant y poractant alfa. Ocurrieron 30 (32,3 por ciento) muertes, 8 (25,8 por ciento) para bovactant, 10 (32,3 por ciento) beractant y 12 (38,7 por ciento) poractant alfa (p > 0,05). La mortalidad y/o DBP ocurrió en 10 (32,2 por ciento) neonatos con bovactant, 10 (32,2 por ciento) con beractant y 14 (45,2 por ciento) con poractant alfa (p > 0,05). Conclusiones: Los resultados primarios y secundarios entre los tres surfactantes evaluados fueron muy similares...

Introduction: Hyaline membrane disease is an important cause of neonatal mortality. The objective of this research is to evaluate the efficacy of three different exogenous surfactants in premature infants. Patients and Method: A retrospective cohort analysis in 93 preterm infants > 24 weeks and birth weight > 500 g was performed, 31 infants for each surfactant. Exposure consisted of the 1st dose of bovactant (Alveofact®) 50 mg/kg, beractant (Survanta®) 100 mg/kg initially, and poractant alfa (Curosurf®) 200 mg/kg. The variables included duration of mechanical ventilation, duration of oxygen therapy, hospital stay, need for second dose of surfactant, adverse events surfactant administration and prematurity complications. Mortality and bronchopulmonary dysplasia (BPD) were evaluated. Statistical analysis was performed using Stata® 11.0, X² or Fisher exact test for qualitative variables and ALNOVA or Kruskal-Wallis tests for quantitative and association relative risk, all with 95 percent confidence level. Results: There were no gender, weight and gestational age differences at birth among the three groups. No statistically significant differences were found regarding duration of mechanical ventilation, duration of oxygen therapy, administration of a second dose of surfactant, hospital stay and complications among the three groups. Adverse events related to surfactant administration occurred for beractant and poractant alpha. There were 30 (32.3 percent) deaths, 8 (25.8 percent) associated to bovactant, 10 (32.3%) to beractant and 12 (38.7 percent) to poractant alpha (p > 0.05). Mortality and/or BDP occurred in 10 (32.2 percent) infants who received bovactant, 10 (32.2 percent) beractant and 14 (45.2 percent) with poractant alpha (p > 0.05). Conclusions: The primary and secondary outcomes among the three surfactants tested were similar, taking into account the limitations of the work.

Unexpected extra-renal effects of loop diuretics in the preterm neonate.

UNLABELLED: The loop diuretics furosemide and bumetanide are commonly used in neonatal intensive care units (NICUs). Furosemide, because of its actions on the ubiquitous Na(+) -K(+) -2Cl(-) isoform cotransporter and its promotion of prostanoid production and release, also has non-diuretic effects on vascular smooth muscle, airways, the ductus arteriosus and theoretically the gastrointestinal tract. Loop diuretics also affect the central nervous system through modulation of the GABA-A chloride channel. CONCLUSION: The loop diuretics have a variety of biological effects that are potentially harmful as well as beneficial. Care should be taken with the use of these agents because the range of their effects may be broader than the single action sought by the prescribing physician.

Estrategia de intervención para disminuir la mortalidad por Síndrome de Dificultad Respiratoria del recién nacido en Maternidad Provincial, de Matanzas / Interventional strategy to diminish mortality by Respiratory Distress Syndrome of the newborn at the Provincial Maternity Hospital, of Matanzas

En la presente investigación se expone una estrategia de intervención dirigida a disminuir la mortalidad por Síndrome de Dificultad Respiratoria del Recién Nacido, en el Hospital Provincial Ginecobstétrico Docente Julio Alfonso Medina, de Matanzas. Sobre la base de la propia experiencia de los autores y mediante la aplicación de métodos científicos, basados en la literatura internacional actual, se presenta el resultado de un minucioso estudio de 48 recién nacidos que padecieron la enfermedad y que fueron tratados en la Unidad de Cuidados Intensivos Neonatales de esa institución hospitalaria durante los años 2006 y 2007. Las acciones estratégicas que se dan a conocer como resultado de la investigación, unido a las recomendaciones ofrecidas por los autores, constituyen una herramienta imprescindible para emprender un mejor manejo con los pacientes que padecen la enfermedad. Apoyados en el uso de una secuencia correcta del CPAP y del surfactante porcino cubano denominado SURFACEN, se dan a conocer nuevos enfoques en el tratamiento del Síndrome de Dificultad Respiratoria del Recién Nacido. Se propone el nuevo término de Enfermedad Pulmonar por Inmadurez Congénita (EPIC), para designar esta patología en lugar del término anatomopatológico de membrana hialina...

In the current investigation we expose the interventional strategy to diminish mortality by Respiratory Difficulty Syndrome of the Newborn, in the Provincial Gynecoobstetric Teaching Hospital Julio Alfonso Medina, of Matanzas. On the basis of the authors' proper experience and applying scientific methods, taking into account the current international literature, we present the results of a detailed study of 48 newborns who suffered the disease and were treated in the Neonatal Intensive Care Unit of this institution during 2006 and 2007. The strategic actions resulting from our investigation, together with the recommendations offered by the authors are indispensable for a better management of the patients suffering the disease. We offer new approaches in the treatment of the Respiratory Distress Syndrome of the Newborn on the basis of the usage of a correct sequence of the Continuous Positive Airway Pressure and the porcine Cuban surfactant called SURFACEN. We propose the new term Pulmonary Disease by Congenital Immaturity, to denominate this pathology in the place of the anatomopathologic term of hyaline membrane...

Comparison outcomes of surfactant therapy in respiratory distress syndrome in two periods.

BACKGROUND: Exogenous surfactant replacement therapy has been a part of the routine care of preterm neonates with respiratory distress syndrome (RDS) since 1990s. In Thailand, the utilization of surfactant replacement therapy had been limited due to the high cost until the National Health Insurance Policy began in 2003 which covered the cost of surfactant. Nowadays surfactant replacement therapy is more frequently used at Queen Sirikit National Institute of Child Health, so the authors were interested in evaluating its use in RDS. OBJECTIVES: To compare the outcome and complications of surfactant replacement therapy in newborns who were diagnosed with moderate to severe RDS during two times period. STUDY DESIGN: Retrospective study. MATERIAL AND METHOD: The data of infants who were diagnosed as moderate to severe RDS and treated with surfactant at Queen Sirikit National Institute of Child Health between January 1st, 2003 and December 31th, 2005 were reviewed. The outcome of this study (Group II) was compared to the previous study conducted in 1999-2002 (Group I). The complications, mortality rate, association time of start surfactant and duration of ventilation were reviewed. RESULTS: The data of ninety-one moderate to severe RDS patients who received surfactant replacement therapy were reviewed. The mean birth weight and gestational age in this group were 1250 +/- 435.57 gm and 29.38 +/- 2.2 week less than in the first group 1,344 +/- 452.37gm and 29.69 +/- 2.61 week. The second group showed statistical differences in antepartum hemorrhage (4.4%) and pregnancy induced hypertension (PIH) (17.6%) while the first group had 33.3% ofantepartum hemorrhage and 3% of PIH. In neonatal conditions, there were statistical significant differences in anemia 28.6% in group II compared to 9% in group I and patent ductus arteriosus 67% in group II compared to 39.4% in group I. Surfactant was given earlier in life (4.75 +/- 2.76 hours) in the second group compared to the first group (7.21 +/- 4.92 hour) and the overall duration ofpatients on mechanical ventilation in Group II (6 days) was shorter than in Group I (16 days). This was especially more evident in patients who received surfactant within the first six hours of life. The immediate complication, pulmonary hemorrhage was found in more cases in Group I (33.3%) than in Group II (12.1%) but bronchopulmonary dysplasia (BPD) was found to be a late complication in more cases in Group II (46.1%) than in Group I (21.2%). The mean length of admission was longer in Group II (61.23 +/- 41.08 days) compared to Group I (38.5 +/- 23.48 days) and the mortality rate in Group II was 18.7% (17 cases) lower than Group I 33.3% (11 cases). CONCLUSION: Surfactant therapy in moderate to severe RDS can shorten the duration of ventilation and decrease the mortality rate, but has no effect in decreasing the incidence of chronic lung disease. Nevertheless the earlier the surfactant therapy is started, the higher the survival rate.

The use of inhaled nitric oxide in a wide variety of clinical problems.

Inhaled nitric oxide (NO) clearly decreased pulmonary vascular resistance in pediatric patients with pulmonary hypertension, regardless of the underlying origin of the pulmonary hypertension. In persistent pulmonary hypertension of the neonate (PPHN) and CHD, the use of inhaled NO appears to improve the outcome of these patients. In acute respiratory distress syndrome (ARDS) and surfactant deficiency the role of inhaled NO therapy remains unclear. The use of inhaled NO is safe in a carefully monitored setting with a delivery system designed to minimize the generation of NO2.

Retinopathy of prematurity in infants less than 29 weeks' gestation: 3 1/2 years pre- and postsurfactant.

OBJECTIVE: To determine the effects of surfactant on retinopathy of prematurity (ROP). DESIGN: We compared infants for 3 1/2 years both before and after the introduction of surfactant in our neonatal intensive care unit (NICU) using prospectively collected data. Exogenous surfactant (Exosurf) was introduced into our NICU on July 1, 1991. METHODS: We compared the incidence and severity of ROP in two groups of infants born at less than 29 weeks' gestation who required cryo- or laser therapy. Premature infants born during the first 3 1/2 years following the introduction of surfactant were compared with those born during the 3 1/2-year period prior to its introduction. The infants were examined by one ophthalmologist (J.K.) and classified according to the International Classification of ROP. RESULTS: A total of 124 infants born presurfactant and 152 infants born postsurfactant were examined for the presence of ROP. No significant difference between the two groups regarding any stage of ROP or the necessity for treatment was found. In infants of less than 27 weeks' gestation, a significant reduction in the number requiring cryo- or laser therapy was noted (12 of 48 examined [25.0%] vs 6 of 62 examined [9.7%], respectively; P < 0.05). This decreased need for treatment, however, was found in infants without hyaline membrane disease who did not receive surfactant. CONCLUSION: Exosurf has had no significant impact on the incidence or severity of ROP. Due to its effect on improved survival rates, the surfactant produces a larger proportion of infants at risk of developing ROP. Other changes in NICU protocol may be causing a reduction in the incidence of severe ROP.

Morbimortalidad en recién nacidos prematuros menores o iguales a 1000 grs. en quienes se utilizó surfactante pulmonar / Morbi-mortality in premature newborns under 1000g of weight who were given pulmonary surfactant

Objetivo. Determinar la morbimortalidad en recién nacidosprematuros con peso de 1000 gms o menos, que cursaron con enfermedad de membrana hialina a los se les aplicó surfactante pulmonar en forma terapéutica o profiláctica. Diseño. Estudio retrospectivo, descriptivo realizado en una Unidad de Cuidado Intensivo Neonatal. Población. Todos los recién nacidos prematuros menores o iguales a 1000 gms. que nacieron en el período comprendido de noviembre de 1991 a marzo de 1997 y a quienes se les aplicó surfactante pulmonar. Metodología. Revisión de expedientes clínicos y de los libros de la Unidad Neonatal para obtener información de morbilidad y mortalidad. Al obtener los datos se efectuó un análisis descriptivo de los mismos.Resultados. Se obtuvieron 34 expedientes. El sexo predominante fue el masculino (53/100) y el grupo de mayor mortalidad (54/100).Los pesos al nacimiento con mayor incidencia fueron entre 701 a 800 gms. y la edad gestacional entre 27 a 28 semanas. La mortalidad fue mayor en los recién nacidos con pesos entre 701 y 800 gms. Las complicaciones observadas fueron principalmente por prematurez que por el uso de oxígeno, ventilación mecánica o el uso de surfactante, tales como hipertensión pulmonar, hemorragia intraventricular y enterocolitis necrotizante. El 36/100 de los pacientes sobrevivió con terapia profiláctica o de rescate.Recomendaciones. Seguir aplicando surfactante artificial en todos aquellos recién nacidos prematuros con enfermedad de membrana hialinaya sea en forma profiláctica o de rescate.

Hyaline membrane disease (HMD) therapy in Latin America: impact of exogenous surfactant administration on newborn survival, morbidity and use of resources.

Impact of surfactant administration, on neonatal mortality, morbidity and resource use, was assayed in a historically controlled study in 19 NICUs from 5 Latin American countries. Data from clinical records of infants with HMD were retrospectively reviewed for the previous 2 years (PRE phase n = 666 cases), and prospectively in cases that received surfactant (SURF phase, 348 cases). Birth weight stratified relative risk, with 95% confidence interval (RR +/-95% CI) for death, in the SURF as compared to the PRE was 0.60 (0.49-0.74), 0.79 (0.68-0.92) and 0.82 (0.71-0.94), for days 7, 28 and at discharge, respectively. At all ages mortality was significantly lower during SURF. Significant increases were observed in the occurrence of pulmonary interstitial emphysema, pulmonary hemorrhage, patent ductus arteriosus, bronchopulmonary dysplasia, intrahospital infection and necrotizing enterocolitis. Resource use increased significantly. It is concluded that the use of surfactant in the region is an important advance, and the efficacy of management of the late complications of the very premature and labile HMD survivors must increase. More attention should be given to thermal regulation, nutrition and management of infection in the survivors, before a more marked effect of surfactant can be seen.

Subependymal caudothalamic groove hyperechogenicity and neonatal chronic lung disease.

Chronic lung disease is associated with several poorly defined risk factors for impaired cerebral development. Late neonatal onset of subependymal hyperechogenic areas in the caudothalamic groove has been reported in association with dexamethasone treatment and postnatal cytomegalovirus infection. We reviewed charts of 18 patients who developed subependymal hyperechogenicity beyond the first week of life, as well as charts of 79 patients belonging to a prospective surfactant study group. Thirteen of the 18 patients with subependymal hyperdensities had been treated with surfactant and were all found in the subgroup with chronic lung disease. In the surfactant-treated patients who did not develop chronic lung disease, we could not find any patient with subependymal hyperdensities. From the remaining five patients with ultrasound lesions, but who were not treated with surfactant, three had developed chronic lung disease. There was no evident association with dexamethasone treatment or cytomegalovirus infection. Our results support the idea of an association between chronic lung disease and the described echographic lesions in the caudothalamic groove, but the nature of the link between them is still unclear.

Differences in immediate and short-term outcome of premature neonates treated with two types of exogenous surfactant preparation.

A retrospective review of the use of 2 types of exogenous surfactants was done to detect any differences in the short-term outcome. A total of 77 babies received surfactant replacement during the 1 year and 6 months under review. Of these, 30 had received a modified natural preparation, Survanta, and 47 had received a synthetic preparation, Exosurf. The median age at which the surfactant had been administered was at 4 hours of life. Twenty-three percent of all infants had received antenatal steroids. The infants who had received Survanta showed a more rapid initial response, with a lowering of oxygen requirements 1 hour after administration and improvements in the alveolar-arterial oxygen ratios. At 4 hours after administration, the mean arterial-alveolar oxygen ratio was 0.25 +/- 0.15 in the group given Survanta compared with 0.17 +/- 0.11 in the group treated with Exosurf (P < 0.05). These differences however did not persist beyond the first 12 hours after therapy. There were no significant differences between the 2 groups of infants in terms of survival, development of bronchopulmonary dysplasia, intraventricular haemorrhage or ventilator days. A haemodynamically significant patent ductus arteriosus was clinically evident significantly earlier in babies who had received Survanta (mean age 1.86 days against 2.38 days, P = 0.04). The modified natural surfactants appeared to have a more rapid onset of action. The haemodynamic consequences of this more rapid onset of action have to be anticipated in such infants.

The selection of infants for surfactant replacement therapy under conditions of limited financial resources.

The cost of surfactant replacement therapy (SRT) will restrict its use under conditions of limited health resources. Before the local advent of SRT, infants ventilated for hyaline membrane disease (HMD) had an overall survival rate of 87% and an incidence of bronchopulmonary dysplasia of 6.4%. This, together with the cost of SRT, prompted a study to identify those infants who would benefit the most from SRT. Twenty-two infants assessed as having severe HMD were randomised to receive SRT at 3 - 4 hours (9) or at 6 - 8 hours (13) after birth. Two infants (15%) in the latter group did not require SRT. The outcome of these two groups was the same. Of 56 infants assessed as having moderate HMD, only 24 (43%) qualified for SRT from 6 hours of age. The outcome of the SRT and non-SRT infants was comparable. The group of infants with moderate HMD had a significantly better outcome than those with severe HMD. A limited period of observation to assess the severity of illness did not compromise outcome in this group of 78 infants with moderate to severe HMD.

The cost and effectiveness of surfactant replacement therapy at Johannesburg Hospital, November 1991-December 1992.

OBJECTIVE: To assess the impact of surfactant replacement therapy (SRT) on the outcome of hyaline membrane disease (HMD) and to assess the cost implications of a policy of selective administration of artificial surfactant. DESIGN: The short-term outcome of 103 newborns ventilated for HMD (61 selected for SRT according to initial and/or ongoing oxygen requirements) was compared with that of a historical control group of 173 infants ventilated for HMD before the introduction of SRT. MAIN OUTCOME MEASURES: Mortality and morbidity of HMD including death, bronchopulmonary dysplasia, pneumothorax, pulmonary haemorrhage, patent ductus arteriosus and intraventricular haemorrhage. RESULTS: There were significant demographic differences between the treatment and control groups (black patients 74% v. 28%, P < 0.0001; unbooked mothers 72% v. 15%, P < 0.0001) as well as evidence of more severe lung disease in the treatment group (pressor support 44% v. 27%, P < 0.005; and paralysis during ventilation 38% v. 25%, P < 0.005). Pneumothorax was reduced in the SRT group (7% v. 17%, P < 0.01). There were no significant differences between the two groups in the incidence of BPD or mortality. The use of SRT added to the total cost of treating a patient ventilated for HMD. CONCLUSION: The selective use of SRT had the effect of converting severe disease into moderate disease rather than achieving maximal benefit in all cases of HMD through routine use of the product. A policy of restricting use may result in cost savings where resources are limited.

The late administration of surfactant.

Current recommendations for surfactant replacement therapy (SRT) in the treatment of hyaline membrane disease (HMD) are to administer the drug as soon as possible after starting ventilation in order to prevent ventilator lung damage. We present a review of 18 infants (gestational age 32.4 +/- 1.9 weeks and birth weight 1,795 +/- 427 g) who received the initial dose of SRT after they were 12 hours old. Fourteen infants were assessed as having HMD and 4 as having congenital pneumonia. Overall there was a significant and sustained improvement in oxygenation as measured by arterial/alveolar oxygen ratios. The outcome of these infants was good, with a duration of ventilation of 7.9 +/- 4.3 days and a duration of hospitalisation of 26.2 +/- 12.6 days. No infant developed bronchopulmonary dysplasia. Of particular interest is that 3 infants weighing > 2,400 g with congenital pneumonia responded to a single delayed dose of SRT. Late SRT is effective and there may be a place for SRT in the treatment of conditions other than HMD.

Inhaled nitric oxide improves gas exchange and lowers pulmonary vascular resistance in severe experimental hyaline membrane disease.

To determine the effects of inhaled nitric oxide (NO) on pulmonary hemodynamics and gas exchange in experimental hyaline membrane disease (HMD), we studied 16 premature lambs (0.78 term) in two separate protocols. All animals were treated with exogenous surfactant before mechanical ventilation. In protocol 1, we measured the acute response to brief treatment with inhaled NO (20 ppm, 20 min) after 2 h of mechanical ventilation with fraction of inspired oxygen of 1.00 (n = 5). After 2 h, brief NO treatment lowered pulmonary vascular resistance from 0.26 +/- 0.05 to 0.16 +/- 0.03 mm Hg.(mL/min)-1 (p < 0.01) and improved gas exchange (arterial PO2, 44 +/- 9 mm Hg baseline to 168 +/- 45 mm Hg NO, p < 0.01; arterial PCO2 45 +/- 5 mm Hg baseline to 35 +/- 4 mm Hg NO, p < 0.05). In protocol 2, to determine whether early and continuous treatment with inhaled NO could sustain improvement in gas exchange and pulmonary hemodynamics in severe HMD, we compared the physiologic effects of ventilation with high inspired oxygen concentrations for 3 h with NO (20 ppm, n = 6) and without NO (controls, n = 5). After 3 h, the NO treatment group had sustained reduction in pulmonary vascular resistance (0.10 +/- 0.01 mm Hg.(mL/min)-1 NO versus 0.25 +/- 0.04 mm Hg.(mL/min)-1 control, p < 0.05), increased left pulmonary artery blood flow (204 +/- 24 mL/min NO versus 109 +/- 15 mL/min control, p < 0.05), and increased arterial PO2 (114 +/- 27 mm Hg NO versus 36 +/- 11 mm Hg control, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Surfactant protein B deficiency: antenatal diagnosis and prospective treatment with surfactant replacement.

An infant with a family history of congenital alveolar proteinosis associated with surfactant protein B (SP-B) deficiency was identified when SP-B was not detected in amniotic fluid obtained at 37, 38, and 40 weeks of gestation. Surfactant replacement with commercially available preparations that contained SP-B was begun soon after delivery. Progressive respiratory failure developed despite continued surfactant replacement, corticosteroid therapy, and extracorporeal membrane oxygenation. The infant died at 54 days of age while awaiting lung transplantation. Surfactant extracted from amniotic fluid, bronchoalveolar lavage fluid, and lung tissue had no phosphatidylglycerol; surface tension was 24 dynes/cm (normal, < 10 dynes/cm) and did not decrease with in vitro addition of exogenous SP-B. Pulmonary vascular permeability measured with positron emission tomography was twice normal. At autopsy the alveolar proteinosis pattern was less prominent than that seen in affected siblings. Immunoreactivity of SP-B was absent in type II cells, but numerous foreign body granulomas with central immunoreactivity for SP-B and surfactant protein C were present. We conclude that exogenous surfactant replacement did not normalize surfactant composition, activity, or pulmonary vascular permeability. These findings suggest that endogenous SP-B synthesis is necessary for mature surfactant metabolism and function.