Birth Asphyxia

BIRTH ASPHYXIA

Lec. 3
2016-2017


Birth asphyxia or hypoxia- ischemia: it refers to a signs & symptoms of hypoxia which means poor oxygen delivery to body organs that is induced by:- Hypoxemia: which refers to an arterial oxygen concentration of less than normal. If hypoxia is prolonged, cardiac and vascular compromise occur result in hypotension causing: Ischemia: which refers to a blood flow to cells or an organ that is insufficient to maintain their normal function which will result in more tissue hypoxia. Eventually: Tissue anoxia occur which is a term used to indicate the consequences of complete lack of oxygen.
Birth asphyxia or hypoxia- ischemia


After an episode of hypoxia and, anaerobic metabolism occurs and generates increased amounts of lactate and inorganic phosphates. Excitatory and toxic amino acids, particularly glutamate, accumulate in the damaged tissue. Increased amounts of intracellular sodium and calcium may result in tissue swelling and cerebral edema. There is also increased production of free radicals and nitric oxide in these tissues.


Intrauterine: IUGR with increased vascular resistance (by doppler study) may be the 1st indication of fetal hypoxia. During labor: the fetal heart rate slows, continuous heart rate recording may reveal a variable or late deceleration pattern particularly in infants near term. These signs should lead to the administration of high concentrations of oxygen to the mother and consideration of immediate delivery to avoid fetal death and CNS damage. At delivery: the presence of meconium-stained amniotic fluid is evidence that fetal distress has occurred.

Clinical manifestations

Patterns of periodic fetal heart rate deceleration

Stages of HIE

Selective cerebral or whole body (systemic) therapeutic hypothermia reduces mortality or major neurodevelopmental impairment in term and near-term infants with HIE. Hypothermia decreases the rate of apoptosis and suppresses production of mediators known to be neurotoxic, including extracellular glutamate, free radicals, nitric oxide, and lactate. Hyperthermia has been found to be associated with impaired neurodevelopment, so it is important to prevent hyperthermia before initiation of hypothermia. Additional therapy for infants with HIE includes supportive care directed at management of organ system dysfunction. Careful attention to ventilatory status and adequate oxygenation, blood pressure, hemodynamic status, acid-base balance, and possible infection is important.
Treatment

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