Asphyxia Neonatorum.pdf
- 1. Asphyxia Neonatorum( Hypoxia-Ischemia) ( Hypoxic Ischemic Encephalopathy) • Anoxia: the consequences of complete lack of O2 • Hypoxemia: ↓ of arterial concentra on of O2 • Hypoxia: decreased oxygena on to cells or organs • Ischemia: blood flow to cells or organs that is insufficient to maintain their normal func on • Hypoxic ischemic encephalopathy is an important cause of permanent damage to CNS ssue that may result in neonatal death or manifest later as CP or developmental delay • Approximately 20-30% of infants with HIE die in the neonatal period, and ≈33-50% of survivors are le with permanent neurodevelopmental abnormali es (cerebral palsy, mental retarda on). • The greatest risk of adverse outcome is seen in infants with severe fetal acidosis (pH <6.7) (90% death/impairment) and a base deficit >25 mmol/L (72% mortality).
- 2. • Failure of the newborn baby to establish an effec ve respira on immediately a er birth • A er an episode of hypoxia and ischemia, anaerobic metabolism occur, this generate increased amount of lactate, inorganic phosphate, toxic amino acids( glutamate) and these accumulate in the damaged ssues • Increased amounts of intracellular Sodium and Calcium may result in ssue swelling and cerebral edema • There is also increased produc on of free radicals and nitric oxides in these ssues
- 3. Early conges on, fluid leak from increased capillary permeability, and endothelial cell swelling may then lead to signs of coagula on necrosis and cell death. Prolonged intrauterine hypoxia may result in inadequate perfusion of the periventricular white ma er, resul ng in turn, in PVL par cularly in preterm infants. Term infants demonstrate neuronal necrosis of the cortex (later, cor cal atrophy)
- 4. • E ology: 1. Fetal hypoxia: a. maternal hypoxia: hypoven la on during anesthesia, chronic pulmonary or cardiac diseases, resp failure b. maternal hypotension: acute blood loss, spinal anesthesia, compression of the vena cava by the gravid uterus c. uterine tetany caused by excess oxytocin( inadequate relaxa on of uterus to permit placental filling) d. premature separa on of the placenta e. cord compression or kno ng f. placental insufficiency from toxemia or postmaturity
- 5. 2. A er birth: a. failure of oxygena on as a result of severe forms cyano c CHD, severe pulmonary disease b. severe anemia( hemorrhage, hemoly c disease) c. shock: interfere with the transport of O2 to vital organs; overwhelming sepsis , massive blood loss, I C or adrenal hemorrhage
- 7. • The effects of Asphyxia: 1. CNS: HIE, infarc on, hemorrhage, cerebral edema, seizures, hypotonia, hypertonia 2. CVS: myocardial ischemia, poor contrac lity, hypotension, tricuspid insufficiency 3. pulmonary: P. HTN, hemorrhage, RDS 4. renal: acute cor cal or tubular necrosis 5. adrenal : hemorrhage 6. GI: perfora on, ulcera on with HGE, necrosis 7. metabolic: ISADH, hypo Na, hypoglycemia, hypo Ca, myoglobinuria
- 8. 8. Integument: subcutaneous fat necrosis 9. hematology: DIC Management 1. Iden fica on of at risk infants: a. prenatal: -Intrauterine growth restric on may develop in chronically hypoxic fetuses without the tradi onal signs of fetal distress - fetal acidosis ( PH less than 7.0) - Doppler umbilical waveform velocimetry ( demonstra ng increased fetal vascul R) - cordocentesis: hypoxia, lac c acidosis -a variable or late decelera on pa ern Par cularly in infants near term, these signs should lead to the administra on of high concentra ons of oxygen to the mother and considera on of immediate delivery to avoid fetal death and CNS damage.
- 9. b. at birth:- yellow meconium stained amnio c fluid( fetal distress) - pallor, cyanosis, apnea, bradycardia, unresponsiveness to s mula on 2. Assessment: a. APGAR score b. Amplitude Integrated EEG: help to determine which infants are at highest risk for long-term brain injury
- 11. c. MRI: Diffusion-weighted MRI is the preferred imaging modality in neonates with HIE because of its increased sensi vity and specificity early in the process and its ability to outline the topography of the lesion 3. Treatment: a. resuscita on
- 12. The goals of neonatal resuscita on are to prevent the morbidity and mortality associated with hypoxic-ischemic ssue (brain, heart, kidney) injury and to reestablish adequate spontaneous respira on and cardiac output. High-risk situa ons should be an cipated from the history of the pregnancy, labor, and delivery and iden fica on of signs of fetal distress. Infants who are born limp, cyano c, apneic, or pulseless require immediate resuscita on before assignment of the 1-min Apgar score. Rapid and appropriate resuscita ve efforts improve the likelihood of preven ng brain damage and achieving a successful outcome.
- 14. b. systemic or selec ve cerebral hypothermia: suppress the produc on of neurotoxic mediators as glutamate, free radicals, NO, and lactate. Systemic hypothermia may result in more uniform cooling of the brain and deeper CNS structures. Infants treated with systemic hypothermia have a lower incidence of cor cal neuronal injury on MRI. c. Careful a en on to ven latory status and adequate oxygena on, blood pressure, hemodynamic status, acid-base balance, and possible infec on is important. Secondary hypoxia or hypotension due to complica ons of HIE must be prevented. Aggressive treatment of seizures is cri cal and may necessitate con nuous EEG monitoring. Prognosis depends on: 1. ini al cord or ini al blood pH <6.7 have a 90% risk for death or severe neurodevelopmental impairment at 18 mo of age. 2. infants with Apgar scores of 0-3 at 5 min, high base deficit (>20-25 mmol/L), decerebrate posture, and lack of spontaneous ac vity are also at increased risk for death or impairment.
- 15. 3. Gesta onal age 4. The severity of encephalopathy: severe encephalopathy, characterized by flaccid coma, apnea, absence of oculocephalic reflexes, and refractory seizures, is associated with a poor prognosis 5. A low Apgar score at 20 min, absence of spontaneous respira ons at 20 min of age, and persistence of abnormal neurologic signs at 2 wk of age also predict death or severe cogni ve and motor deficits. 6. severe MRI and EEG abnormali es predict a poor outcome as Microcephaly and poor head growth during the 1st year of life
- 16. External cardiac compression in neonate using 2 fingers
- 17. The posi on of the ambu bag on the nose and mouth
- 18. Head lt and jaw li