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Lecture III Neonatal Asphyxia & Its Complications
(新生儿窒息及其并发症)
Department of Pediatrics
Soochow University Affiliated Children’s Hospital
Part INeonatal Asphyxia
新生儿窒息
Aim & Claim
• Understand the assessment & care of normal
birth
• Familiar with the pathogenesis of birth asphyxia
• Hold of Apgar score & ABCDE resuscitation
• Familiar with the complication of severe
asphyxia
Definition
Birth asphyxia is defined as a reduction of
oxygen delivery and an accumulation of carbon
dioxide owing to cessation of blood supply to the
fetus around the time of birth.
This is pathologic condition referred to neonate who have no spontaneous breathing or represented irregular breathing movement after birth. Usually caused by perinatal hypoxia. It is emergency condition and need quickly treatment (resuscitation,复苏).
Etiology
Pathologically, any factors which interfere
with the circulation between maternal and fetal
blood exchange could result in the happens of
perinatal asphyxia. These factors can be
maternal factor, delivery factor and fetal factor.
Etiology—High Risk Factors
• Maternal factor:
hypoxia, anemia, diabetes, hypertension, smoking, nephritis, heart disease, too old or too young,etc
• Delivery condition:
Abruption of placenta, placenta previa, prolapsed
cord, premature rupture of membranes,etc
• Fetal factor:
Multiple birth, congenital or malformed fetus,etc
Pathophysiology
When fetal asphyxia happens, the body
will show a self-defended mechanism which
redistribute blood flow to different organs
called “inter-organs shunt” in order to prevent
some important organs including brain, heart
and adrenal from hypoxic damage.
Pathophysiology(I)
Hypoxic cellular damages:a. Reversible damage(early stage):
Hypoxia may decrease the production of
ATP, and result in the cellular functions . But
these change can be reversible if hypoxia is
reversed in short time.
b. Unreversible damage:
If hypoxia exist in long time enough, the cellular
damage will become unreversible that means
even if hypoxia disappear but the cellular
damages are not recovers. In other words, the
complications will happen.
Pathophysiology(II)
Asphyxia development:a. Primary apnea
breathing stop but normal muscular tone or hypertonia(肌张力增高), tachycardia (quick heart rate), and hypertension
Happens early and shortly, self-defended mechanism,
could not be damage to organ functions if corrected quickly
b. Secondary apnea
Features of severe asphyxia or unsuccessful
resuscitation, usually result in damage of organs
function.
Pathophysiology(III)
Other damages:a. Persistent pulmonary hypertension (PPHN)
b. Hyper/hypoglycemia
c. Hyperbilirubinemia
Clinic manifestations
Fetal asphyxia
fetal heart rate: tachycardia bradycardia
fetal movement: increase decrease
amniotic fluid: meconium-stained
Clinic manifestations
• Apgar score:A: appearance(skin color)
P: pulse(heart rate)
G: grimace(reactive ability)
A: activity(muscular tension)
R: respiration
APGAR score
Score 0 1 2Heart rate none <100 > 100Respiration none irregular regularMuscle tone limp reduced normalResponse to none grimaced coughstimulation
Color of trunk white blue pink
Degree of asphyxia:
Apgar score 8~10: no asphyxia
Apgar score 4~8: mild/cyanosis asphyxia
Apgar score 0~3: severe/pale asphyxia
Clinic manifestations
Complications:CNS: HIE, ICH
RS: MAS, RDS, pulmonary hemorrhage
CVS: heart failure, cardiac shock
GIS: NEC, stress gastric ulcer
Others: hypoglycemia, hypocalcemia(低钙血
症), hyponatremia(低钠血症)
Diagnosis
1/ Evidence of fetal distress
2/ Fetal metabolic acidosis
3/ Abnormal neurological state
4/ Multiorgan involvement
Management
• ABCDE resuscitation• A (air way)
• B (breathing)
• C (circulation)
• D (drug)
• E (evaluation)
Airway
1/ open by placing the head in the neutral position
2/ clean up completely amniotic fluid from the airway
by suction with syringe( 注射器)as soon as
possible
3/ if meconium-stained, tracheal catheter(气管插管)
should be placed to ensure meconium to be
removed
Breathing
1/ ensure face mask covers nose & mouth connect to oxygen bag
2/ establish respiration of 30-40/min with chest wall movement
3/ if no response, intubation & mechanic ventilation(通气) is necessary
Circulation
1/ if heart rate <60/bpm, start external cardiac compression with fingers
2/ ratio 3:1 ( 90 compressions to 30 bpm)
Drugs 1/ if profound bradycardia(心动过缓), give adrenaline(肾
上腺素) (1:10000, 0.1-0.3ml/kg) by endotracheal(气管内) tube or umbilical vein
2/ if no response, intravenous fluid (saline, albumin, plasma, blood) with 10ml/kg
3/ if acidosis, give 5% sodium bicarbonate (SB) with 3-5ml/kg
4/ if bradypnea, consider using naloxone(纳洛酮)(0.1mg/kg)
Evaluation
Evaluate the result of resuscitation to
determine if more rescue necessary:
– If not good, repeat the resuscitation
– If good, transmit baby to NICU
Remember
In the whole resuscitation,
the most important step is A ---
clean up completely the airway
Part IIHypoxic Ischemic
Encephalopathy (HIE)
(新生儿缺氧缺血性脑病)
Aim & Claim
• Familiar with the severity of HIE
• Familiar with the management of HIE
Definition
The brain damage after perinatalasphyxia and the most severe condition showed high mortality or remain cerebral complications such as mental retardation & cerebral palsy.
Clinically, more term babies suffered from this disease than premature babies.
Pathologically, more premature babies suffered from this disease than term babies.
Etiology & Pathology
• Etiology
The most and direct cause of HIE is
perinatal asphyxia.
• Pathology
Pathophysiology
• Cerebral blood flow
early stage: normal (intraorgans shunt)
then slow down (selective vulnerability)
finally ischemia
• Cerebral metabolism
Clinic Manifestation
The clinic features of HIE are
mainly symptoms of consciousness
which usually represent in tow types:
Excitation: hyperalert(激惹), irritable,
hypertonia, tachycardia, tachypnea, seizure,
etc
Depressing: coma, hypotonia, bradycardia,
bradypnea, unresponsibility, etc
Classification—Clinic
• Mild(stage I): hyperalert, irritable, normal muscular
tone & reflex, no seizure, normal EEG
• Moderate(stage II): lethargy, hypotonia, weak
sucking & Moro response, often seizure, EEG+
• Severe(stage III): coma, absent muscular tone &
reflex, persistent seizure, EEG++
Classification—CT
• Stage I(normal): no hypodensity(低密度)
• Stage II(mild): local or patchy hypodensity
• Stage III(moderate): hypodensity in tow area of brain or more,
usually no hemorrhage
• Stage IV(severe): extensive & generalized hypodensity, usually
combined with brain hemorrhage
轻度:散在或局限性低密度改变,在2个脑叶以内
中度 : 低密度改变超过2个脑叶,灰白质对比模糊
中度不伴出血中度不伴出血
中度伴出血中度伴出血
重度 : 弥漫性低密度改变, 灰白质界限消失,脑室受压。 中、重度HIE 常伴ICH。
颅内出血
Management(I)
Generalized treatment: – Ventilation: CPAP, CMV, HFOV– Circulation: Dopamine(多巴胺)
/Dobutamine(多巴酚丁胺)
– Energy: normal glucose – Fluid: restriction < 60-80ml/kg/d
Management(II)
Control of seizures:– Phenobarbital(苯巴比妥):
loading dose 15-20mg/kg, iv
maintenance dose 3-5mg/kg, iv
– Diazepam(安定): 0.1-0.3mg/kg, iv
– Chloralhydrate(水合氯醛): 50mg/kg, E
Management(III)
Cerebral edema & high pressure
– Furosemide(速尿): 1mg/kg, iv, q4-12h
– Mannitol(甘露醇): 0.5g/kg, iv, q8-12h
– Albumin(白蛋白): 0.5-1.0g/kg, iv
Prognosis
Depend on the severity of brain damage &
medical treatment, usually:
Mild or moderate cases could be cured completely, but
severe cases represent poor prognosis with high
mortality or cerebral complications such as mental
retardation & cerebral palsy.
Prevention
• Perinatal healthy care
• Prevention of asphyxia
Part IIIIntracranial Hemorrhage (ICH)
(颅内出血)
Aim & Claim
• Familiar with the etiology of ICH
• Familiar with the characterastic of all types
of ICH
Introduction
The intracranial hemorrhage (ICH) is
one of the most common and dangerous
disease with very high mortality &
disability rate in alive cases.
• The morbidity is higher in premature infants than in
term ones.
• There are differing etiology and varying prognosis.
With improvement in perinatal care, there have be
considerable improvement in survival recently.
Etiology & Pathology
Vessels factor Pressure factor
ICH
Injury factor Other factors
(Vit K deficiency, maternal medication, thrombopenia, etc)
Etiology & PathologyVessels factors
• Premature vessels of neonate especially in
preterm babies is vulnerable to damage
Etiology & PathologyPressure factor
Any change of blood pressure could
interfere with the cerebral circulation
and break the blood vessels
Etiology & PathologyInjury factor
• Any injury during the delivery may
break the blood vessels
Etiology & PathologyOther factors
• Deficiency of vitamin K
• Maternal bleeding or thrombocytopenia(血小板减少
症)
• Maternal medications
Classification of ICH
• Periventricular-intraventricular
hemorrhage(PVH-IVH)
• Primary subarachoid hemorrhage (SAH)
• Intraperenchymal hemorrhage (IPH)
• Subdural hemorrhage (SDH)
• intracerebellar hemorrhage (ICH)
PVH-IVH
• Premature infant, especially VLBW
• Onset early, <72 h
• Depressing symptoms: apnea, hypotonia,
lethargy, no crying, coma
SAH
• Usually have history of birth injury
• Excitation symptom
• Seizure appear in 2nd day
• Bloody cerebral spinal fluid
• Hydrocephalus(脑积水)
IPH
• Usually term baby
• Caused by hypertension
• Poor prognosis
SDH
• Usually huge baby
• Often have injury history
• Onset early: <24h
ICH
• Premature below 32 weeks GA
• Nonspecific features
• Affected vital signs
• Frequent apnea & bradycardia
• Poor prognosis
Diagnosis
History: asphyxia
birth injury
premature, etc
Symptoms & signs:
excitation or depressing
Radiological evidence:
hyperdencity(高密度) (white) on CT or
MRI
Management
General management:keep quiet,
keep normal glucose (5mmol/L)maintain normal blood-gas analysis maintain the balance of vital signs & fluid/energy
Management
• Hemostasis(止血)
– vitamin K, plasma or blood transfusion,
– hemostatic (bleeding stopping
medications)
Management
Control seizure
Phenobarbital
Diazepam
Chloralhydrate
Management
Decreasing intracranial pressureFurosemide(速尿): 0.5-1mg/kg, iv, q8-12h
Dexmethasone(地塞米松):0.5-1.0 1mg/kg, iv, q8-
12h
Albumin(白蛋白): 0.5-1.0g/kg, iv
Mannitol(甘露醇): 0.5g/kg, iv, q8-12h
Management
Treatment of hydrocephalus
serial lumbar punctures
surgery operation
Prognosis
• Related to the severity of bleeding
and locations. High mortality and
instabilities.
Prevention
Prenatal care
Prevention of asphyxia & birth injury
Summery
Neonatal asphyxia and its complication
(HIE, ICH) are the most dangerous
conditions clinically with high mortality and
incidence of poor neurological outcome
Questions
• What is APGAR score ?
• What is the composition of ABCDE
resuscitation ?
Thank you for your cooperation!