Encefalopatía hipóxica-isquémica neonatal / Neonatal hypoxic-ischemic encephalopathy

La encefalopatía hipóxica-isquémica es un síndrome bien definido que afecta a los recién nacidos a término debido a asfixia fetal al nacer. La incidencia es 1-8 de cada 1000 nacidos en países desarrollados y asciende hasta 25 cada 1000 nacidos en países en desarrollo. Las causas más frecuentes son desprendimiento de la placenta, prolapso del cordón umbilical y rotura uterina. El criterio diagnóstico incluye incapacidad parcial o total del recién nacido para llorar y respirar al ser estimulado que requiere ventilación asistida en la sala de partos, Apgar < 5 en 5 y 10 minutos, acidemia (pH ≤ 7 y/o déficit de bases ≥ 12 mmol/l), alteraciones del estado de vigilia/sueño, de los reflejos primitivos y estiramiento muscular y tono muscular. En la forma leve la recuperación es total en tres días y sin (o con mínimas) secuelas de neurodesarrollo. En las formas moderadas y graves existen déficits neurológicos permanentes y alteraciones del neurodesarrollo (48%), 27% mueren y 25% son normales. El EEG regular o amplitud integrada y la resonancia magnética y espectroscópica realizados entre las 24 y las 96 horas y los 7 y 21 días de nacido respectivamente tienen un gran valor diagnóstico y pronóstico. Se recomienda hipotermia corporal (33.5 °C por 72 horas) antes de las 6 horas de nacido en las formas moderadas y graves. El resultado es una disminución de la mortalidad (de 35% a 27%) y de la morbilidad (de 48% a 27%).

Hypoxic-ischemic encephalopathy is a clearly recognizable clinical syndrome of in term newborns due to fetal asphyxia at birth. The incidence is 1.5 (95% CI 1.3 to 1.7) but it ranges from 1-8 and 25 out of every 1000 born in developed and developing countries, respectively. The most frequent causes are detachment of the placenta, prolapse of the umbilical cord and uterine rupture. The diagnostic criteria include partial or total incapacity for the newborn to cry and breath at birth even when stimulated, requiring assisted ventilation in the delivery room, Apgar < 5 in 5 and 10 minutes, acidemia (pH ≤ 7 and / or bases deficit ≥ 12 mmol/l), alterations of the conscience and the reflexes of Moro, grasping and suction, muscular stretching and muscle tone. The clinical forms are mild, moderate and severe. In the mild forms, the recovery is total in three days without, or with minimal, neurodevelopmental alterations. The moderate and severe forms cause permanent neurological deficits and neurodevelopmental alterations (48%) or death (27%). The regular or amplitude integrated EEG and the magnetic and spectroscopic magnetic resonance imaging performed between 24 and 96 hours and 7 and 21 days after birth, respectively, have a high diagnostic and prognostic value. Induced hypothermia (33.5° C for 72 hours) is recommended before 6 hours old. The result is a decrease in mortality (from 35% to 27%) and morbidity (from 48% to 27%).

¿Es posible disminuir la incidencia de encefalopatía hipóxico isquémica? / Is it possible to reduce the incidence of hypoxic-ischemic encephalopathy?

Objetivo: Determinar si una política local, establecida en la Maternidad del Hospital Padre Hurtado (HPH), para bajar la incidencia de Encefalopatía Hipóxico Isquémica es efectiva, sin incrementar en forma relevante la tasa de cesáreas. Diseño: Estudio de cohorte. Escenario: Unidad de Gestión Clínica de la Mujer y el Recién Nacido del Hospital Padre Hurtado. Población: Neonatos mayores de 33 semanas de edad gestacional, nacidos en el Hospital Padre Hurtado durante los años 1999 y 2015. Método: Se revisaron los resultados de una política de intervención para prevención de asfixia neonatal establecida en la Maternidad del Hospital Padre Hurtado durante un periodo de 14 años. Resultados: Al analizar los datos de un total de 102.612 nacidos vivos, se constató una disminución en la incidencia de EHI en sus 3 grados de una tasa de 4.75/1.000 nacidos vivos previo a la intervención (grupo control) a una tasa de 1.46 por 1.000 nacidos vivos post intervenciones, con alta significancia estadística (p=0,008), llegando en los últimos 6 años a tasa promedio de 0.87/1.000 nacidos vivos. La tasa de EHI moderada y severa bajó de 1.15 por mil nacidos vivos a 0.62, también con alta significancia estadística (p=0.02). La tasa de cesáreas oscilo entre 26-29 % en estos años. Conclusión: La introducción de intervenciones protocolizadas y sistematizadas por medio de la implementación de guías de manejo del trabajo de parto, la capacitación del equipo de profesionales y la auditoría continua de los casos de EHI en el Servicio de Maternidad del Hospital Padre Hurtado se asoció a una disminución significativa de EHI, manteniendo la tasa de cesáreas bajo 30%.

Objectives: Determine whether a local policy to reduce the incidence of neonatal hypoxic-ischemic encephalopathy (HIE), established at the Maternity Unit of Hospital Padre Hurtado (HPH), is effective without significantly increasing the cesarean rate. Design: Cohort study. Setting: Maternity unit of Hospital Padre Hurtado. Population: Newborns older than 33 weeks born at Hospital Padre Hurtado between 1999 and 2015. Methods: The results of a training policy to prevent HIE and perinatal asphyxia established at the Maternity unit of Hospital Padre Hurtado were reviewed during a period of 14 years. Results: From a total of 102.612 newborns analyzed, results showed a decrease in all grades of HIE incidence, from a rate of 4.75 / 1,000 live births prior to intervention (control group) to a rate of 1.46 per 1,000 live births after interventions, with high statistically significance (p=0.008), it reached an average rate of 0.87/1000 for the last 6 years. The moderate and severe HIE rate decreased from 1.15/1000 to 0.62/1000, also with high statistically significance (p=0.02). During the same period of time, the cesarean rate varied between 26-29%. Conclusion: The introduction of protocolized and systematized interventions trough the implantation of Management guides, obstetrics emergency trainings to the professional team and continues audit of the HIE cases at the Maternity unit Hospital Padre Hurtado was associated to a significant decrease of HIE, maintaining the rate of cesareans below 30%.

Risk factors for hypoxic-ischemic encephalopathy in asphyxiated newborn infants.

OBJECTIVE: To determine the risk factors for hypoxic-ischemic encephalopathy (HIE) in asphyxiated newborn infants. MATERIAL AND METHOD: A retrospective study of 17,706 newborns, who were admitted to the Neonatal Unit of King Chulalongkorn Memorial Hospital, from July 1999 till the end of December 2000. 84 infants with perinatal asphyxia were enrolled in the present study. All of the possible risk factors that might have contributed to asphyxia were identified and recorded HIE was diagnosed based on the Modified Sarnat-Sarnat Score for the diagnosis of neonatal encephalopathy. The clinical data of the HIE group were compared with those of the HIE negative group. The categorical data were analyzed for statistical significance (p < 0.05) by Chi-square test or Fisher exact test, or Student t-test. The odds ratio and 95% CI were calculated for those with statistical significance. Stepwise multiple logistic regression analysis used to determine the independent factors that may predispose an infant to HIE. RESULTS: Inappropriate antenatal care (OR 9.4; 95%CI: 2.6-35.4), post-term gestation (OR 7.4; 95%CI: 1.4-34.8), vacuum extraction (OR 5.4; 95%CI: 1.1-26.8), male (OR 4.8; 95%CI: 1.3-19.1), prolapsed cord (p = 0.01) and 1 and 5-minute Apgar scores, (p < 0.0001) were significant risk factors for HIE. However, by multiple regression analysis, only a 5-minute Apgar score was significantly associated with HIE (p = 0.001). CONCLUSION: Sophisticated or expensive equipment is not necessary for the treatment of HIE patient. HIE depends mainly on adequate and effective supportive strategy. The delivery of high risk pregnancies, under obstetric facilities and with appropriate intervention and with good neonatal resuscitation, may prevent the perinatal asphyxia and thereby minimize the occurring of HIE.

Gobierno del parto en el Hospital Padre Hurtado: un modelo para contener la tasa de cesárea y prevenir la encefalopatía hipóxico-isquémica / Management of labor in the Padre Hurtado Hospital: an model for the reduction of the cesarean sections and to prevent the hypoxic ischemic encephalopathy

La tasa de cesáreas en Chile se ubicó entre las más altas del mundo en el año 2000: 39 por ciento a 83 por ciento en la práctica privada y 20 por ciento a 28 por ciento en los hospitales públicos. El objetivo de nuestro estudio es comunicar el impacto que ha tenido en la tasa de cesáreas y el resultado neonatal la aplicación de Guías Clínicas para el manejo del trabajo de parto y monitoreo fetal. Entre el 1 de enero de 1999 y el 31 de diciembre de 2004, la tasa global de cesáreas del período fue de 23,2 por ciento y la tasa de fórceps osciló entre 7,5 y 9,7 por ciento. La incidencia de encefalopatía hipóxico-isquémica (EHI) para el período de estudio fue de 3,5/1.000 nacidos vivos, con una progresiva tendencia a la disminución. Las tasas de cesárea y de EHI son comparables a las reportadas en la literatura internacional. Luego de revisar la literatura, ésta es la primera comunicación nacional sobre el impacto de Guías Clínicas en la atención del parto.

Renal failure in asphyxiated neonates.

A prospective case controlled study was conducted in the NICU of a tertiary level referral teaching hospital to determine the incidence of renal failure in asphyxiated neonates and to correlate severity and type of renal failure with Apgar score and hypoxic ischemic encephalopathy (HIE) grading of the neonates. Ninety-eight neonates were enrolled 70 asphyxiated babies and 28 healthy controls. Renal functions were assessed using urinary output, urine microscopy, biochemical parameters and sonographic findings. Babies having renal failure were managed on a protocolised plan and followed up till 6 months of age to detect any residual impairment. Blood urea and serum creatinine were significantly higher in asphyxiated babies compared to the control group. Biochemical derangements correlated well with HIE staging and Apgar scores. There was no significant difference in urine output in the control and the study group as significant oliguria was seen in only 7 of the 70 asphyxiated babies and the output did not correlate with severity of asphyxia. Serum sodium level and fractional excretion of sodium showed significantly different values in the asphyxiated babies compared to control. Of the 70 asphyxiated babies 33 (47.1 %) had renal failure, which was of the non-oliguric type in 78 % cases and oliguric type in 22 % cases. Sonographic abnormalities were seen more often in oliguric babies and was associated with a bad prognosis. Renal parameters normalized in all neonates by 6 months of age. Mortality was higher in babies with oliguric renal failure. We conclude that renal failure is a significant problem in asphyxiated neonates with majority of babies having nonoliguric failure. Severity of renal function abnormality correlates well with degree of asphyxia. Oliguria, hyponatremia and abnormal sonographic scan are bad prognostic signs in renal failure secondary to birth asphyxia.

Prevalência das causas de crise convulsivas neonatais no Hospital Geral de Caxias do Sul / Prevalence of the neonatal seizures causes crises in the General Hospital of Caxias do Sul

As crises convulsivas constituem as mais frequentes das manifestações neurológicas no período neonatal (1,2,3). Muitos autores acreditam que a causa mais frequente seja a encefalopatia hipóxico-isquêmica, mas, devido a maior tecnologia em diagnósticos que se tem atualmente, os erros inatos do metabolismo estariam aumentando de incidências e seriam os mais frequentes. Objetiva-se, com este trabalho, buscar as causas de crise convulsivas neonatais no Hospital Geral de Caxias do Sul e, secundariamente, o tipo de convulsão mais frequente. Realizou-se um estudo de prevalência através da revisão de prontuários do período de junho de 1998 a maio de 2001. Foram estudados 54 prontuários de neonatos e pacientes até um ano de idade, que foram internados no referido hospital com diagnóstico de convulsão. Como resultado, o tipo mais frequente foi o sutil (31,48 por cento). A causa prevalente foi a encefalopatia hipóxico-isquêmica com 48,15 por cento do total. Os dados encontrados não diferenciam daqueles encontrados na literatura.

Hypoxic-ischemic brain damage in perinatal age group.

Cerebral hypoxia-ischemia in the perinatal period continues to be a major contributor to chronic neurologic impairment in children worldwide. Extensive research conducted in the past several years has led to a better understanding of the mechanisms involved in hypoxic-ischemic brain injury. Based on this understanding, the major potential therapeutic approaches being studied include antagonists of excitatory amino acids, calcium channel antagonists, free-radical scavengers, nitric oxide synthase inhibitors, anti-inflammatory agents, trophic factors, and hypothermia. Several agents are in clinical trial phases in adults. However, safety concerns and close relationship between pathomechanisms of hypoxic-ischemic cerebral injury and normal developmental processes have contributed to the slow pace in the neonatal trials. Large multicenter trials including an adequate number of infants will be needed to evaluate efficacy of therapeutic interventions in this particular age group. A large number of risk factors that predispose to hypoxic ischemic injury have been identified. It is important to control these factors and prevent brain damage in the first place. This is especially true for developing countries where resources for treatment with newer agents (when they become available) are likely to be limited. Recent information regarding mechanisms of injury and potential therapeutic measures related to perinatal age are presented in this paper.