Asphyxia and Hypoxic-新生儿缺氧缺血性脑病 (Hypoxic-ischemic Encephalopathy)Asphyxia and Hypoxic-ischemic Encephalopathy

    Show Us What? 概述Pathophysiology of Asphyxia窒息的病理生理

    When and How Asphyxia developed?

    Infants normally breathe within 30 seconds and sustain respiration by 90

    seconds after birth. The real mechanism about breathing beginning remains

    unclear, but the states followed may be related to breath:mild acidosis,hypercarbia, hypoxia, pain, cold, touch, noise, and umbilical cord clamping.

    According to the classic experiment of Dawes on monkey

    1.Respiration changing

    Primary apnea 原发性呼吸暂停

    Secondary or terminal apnea 二次呼吸暂停或终末呼吸暂停The response of newborn monkeys to

    asphyxia

    ?

    pH 7.3 7.0 6.8 6.75 7.1Hypoxic-ischemic Insults to Organs器官功能障碍

    Diving Reflex---Redistribution of blood flow in organs

    [1].Maintain the vital organs : brain ,heat ,adrenal gland

    [2].Ischemic skin, gastrointestine, lung, kidney,muscle

    But the severe hypoxic-ischemic state was not hindered, the

    brain and heart will be in involved soon.

    Disturbance in metabolism and others代谢紊乱

    Mixed acidosis, lower pH;

    Catecholamine and cortisol releasing more儿茶酚胺;

    Hyperglycemia or hypoglycemia血糖改变;

    Free fatty acid increased---arachinoid increased游离脂肪酸；

    Electrolytes abnormalities电解质异常Etiology of Asphyxia 病因

    ? The prevalence of asphyxia in China is about 3.5%-9.0% in general

    large-scale hospitals.

    ? Etiology

    Maternal factors: Diadetes mellitus, chronic illness(eg, anemia,cynotic

    congenital heart disease), hypertension, premature/prolonged rupture of

    membranes, bleeding in second or third trimester, severe pregnance-

    induce hypertesion, substance abuse, maternal infection, multiple

    pregnance

    Fetal factors: preterm gestation(<35weeks),postterm gestation(>42

    weeks), IUGR,size-date discrepancy, Rhesus isoimmunization/hydrop

    fetalis, intrauterine infection, congenital abnomalities

    Intrapartum factors: abnormal presentation, prolapsed cord,prolonged

    labor, umbilical cord knotting, encircling neck tensively, forceps

    delivery, vacuum-assisted delivery,narcotic administration within 4

    hours of delivery, sedative drugs abuseHow to give the diagnosis of asphyxia诊断

    Fetal hypoxia( fetal asphyxia)

    1.Fetal heart rate>160bpm;ominous sign, bradycardia

    <100bpm persists for more 1minute, irregular patterns

    2.FHR monitor showed late deceleration

    3.Meconium stained amniotic fluid

    4.Fetal scalp pH <7.20

    Evaluation at birth---APGAR Score

    1.Heart Rate

    2.Respiratory effort

    3.Skin color

    4.Reflex irritability

    5.Muscle tone0 1 2

    Heart Rate Absent <100bpm >100bpm

    Respiratory effort Absent Slow,irregular Good,crying

    Color Blue,pale Body pink, acrocyanosis Complete pink

    Reflex irritability Absent Grimace Cough, sneeze

    Muscle tone Limp/flaccid Some flexion of extremities Active motion

    Apgar Score System

    Apgar Score 4-7 mild asphyxia

    0-3 severe asphyxia Hypoxic-ischemic multiple organs

    injuries/MOSD

    ? Respiratory system: meconium aspiration syndrome(MAS), pulmonary

    hemorrhage, persistent fetal circulation(PFC/PPHN, persistent pulmonary ......