Monday, March 7, 2011

Perinatal Asphyxia Treatment

Perinatal Asphyxia

    
* Introduction
    
* Clinical Forms
    
Antepartum diagnosis *
    
* Changes postpartum laboratory
    
* Positive Diagnosis
    
* Postasfixic Syndrome
    
* Treatment
    
* Evolution and prognosis
back Treatment
Prophylactic treatment consists of proper monitoring of pregnancy and especially high-risk pregnancy, avoid injury at birth, both hypoxic and mechanical, early diagnosis of chronic or acute fetal distress and birth by cesarean solving, prompt in delivery room resuscitation.
Curative therapy include: respiratory therapy, circulatory therapy, correcting acid-base imbalances, correcting postasfixice complications (brain, heart, kidney), treatment of seizures.
Treatment delivery room provides immediate intervention in the delivery room depending on the degree of damage and subsequent neurological level of the other organs. Will be assessed immediately after birth following three parameters: respiration, heart rate, skin discoloration. Apgar score to assess the timeliness retains effective resuscitation maneuvers, but an Apgar score of 3-5 in 10 minutes and will usually show a severe asphyxia. Resuscitation maneuvers form the ABC of resuscitation known: - A - airway patency; - B - initiation of breathing; - C - Maintenance of traffic; - D - administration of medication.
Airway patency heat loss prevented by immediately placing the infant under a radiant heat source, remove the wet diaper and removing secretions. It is important to maintain thermal neutral point which varies depending on gestational age, to avoid heat losses may worsen asphyxia. Is crucial infant positioning head on one side or the neck in slight hyperextension. Trendelenburg position are no longer used because of the risk of intracranial hemorrhage, especially early. Follow then the dezobstructia oropharynx airway patency and then the nose, with a hole adapted dezobstruare newborn or para rubber. Inserting the probe into the stomach will be after 5 minutes of life, can produce a reflex vagal maneuver, inducing bradycardia and even respiratory arrest. If the infant shows dezobstruarea meconium aspiration will be the endotracheal tube.
Initiation of breathing by tactile stimulation is done by tapping or rubbing the plant with vigorous back flip. Do not persist with this maneuver if the infant does not resume breathing. Positive pressure ventilation and mask balloon at a rate of 40-60 compressions per minute with 100% FiO2 is another method used. Insufflation pressure for the first three is better ventilation of 30-35 cm H2O to relax the lungs. Positive pressure ventilation and mask balloon is replaced after 2 minutes if no results or if the infant shows irregular breathing or diaphragmatic hernia with intubation and ventilation on the endotracheal tube.
Keeping the traffic is external cardiac massage when the heart rate is less than 100 beats per minute after 30 seconds of balloon and mask ventilation or heart rate is 0. Compressions can be made with two fingers behind helping hand, or with two police including the infant in his hands to an imaginary line that runs from 1, 5 cm below the nipple, compression rate is 120 compressions per minute and depth of compressions 1, 5-2 cm to avoid damage to the liver, ribs or xiphoid appendix.
Drug administration is the stimulation of cardiac tissue perfusion ensure correction of acid-base balance. It is used in infants do not respond to positive pressure ventilation and external cardiac massage. Drug administration is catheter umbilical vein or intratracheal. Indicated in neonatal resuscitation medications include: Epinephrine, bicarbonate natru, naloxone, dopamine. Epinephrine is indicated when the heart rate is absent or at a heart rate below 80 beats per minute after 30 seconds of positive pressure ventilation (PPV) and external cardiac massage (MCE). Indications in this volume expander has clinical signs of hypovolaemia and acute hemorrhage. Na bicarbonate in metabolic acidosis is indicated by measuring parameters proved Astrup and inefficiency and prolonged resuscitation, cardiopulmonary arrest unresponsive to resuscitation. Naloxone hydrocloride is used in respiratory depression in the context of the drug morphine mother antepartum administration 4 hours before birth. Precautions regarding the administration of these drugs that can provide so coming seizures in infants of mothers who received chronic treatment with anticonvulsants. Dopamine is a drug used for resuscitation in the delivery room, but is administered in slow infusion in the intensive care unit.
Neonatal resuscitation is stopped after 20 minutes of resuscitation maneuvers if the infant has not resumed breathing but shows the heart beat after 10 minutes if the baby has not resumed breathing and poses no heart beat . Extension of resuscitation after 20 minutes can cause death in hours or days following severe neurological sequelae.
Treatment in the intensive care unit:
In the therapy will monitor cardiac function (blood pressure, heart frequency, respiratory frequency), diuresis whose values must be at least 1-2 ml / kg / hour. Installing diuresis is a good prognostic sign. It will monitor and hemoglobin oxygen saturation, noninvasive methods of blood gases, and acid-base balance.
General measures consist of: achievement of thermal comfort in an incubator, to avoid voltage fluctuations by manipulating and managing the prudent minimum volume expander, oxygen - free flow, cephalic tent, on the mask, CPAP or mechanical ventilation depending on pH, PaO2 and PaCO2 . Try to maintain the pH value between 7, 30 and 7, 35, PaO2 between 50-80 mmHg and PaCO2 below 60 mm Hg (permissive hypercapnia). It is correct acidosis if the pH is below 7-7, 20 and base excess than -11, the correction will be made with 42% of sodium bicarbonate in doses of 2 0 mEq / kg. Bicarbonate administration is slow infusion (30 minutes - 1 hour) to monitor parameters Astrup. Correction of hypoglycemia is required if the serum glucose level is below 40 mg%. We recommend 4-6 mg / kg / min of glucose 10% (rate of hepatic metabolism). Rarely is required rate of 8 mg / kg / min Fighting is hypocalcemia if serum calcium is less than 8 mg% by the administration of calcium gluconate, 200 mg / kg in 10 minutes, followed by 400 mg / kg / day infusion. The importance is that the rapid introduction of calcium may produce bradycardia. It appeals to antibiotic protection, typically with broad spectrum antibiotics (Ampicillin and gentamicin), in doses adapted to the degree of renal impairment. Antibiotic therapy may be interrupted after 24 hours if no risk factors for infection and cultures are sterile. The use parenteral nutrition over a period between 3-5 days to avoid the appearance of intestinal ischemia due ulceronecrotice enterocolitis.
Specific therapy complications: Treatment of cerebral edema: - Fluid restriction between 50-60 ml / kg / day; - Induction of alkalosis by hyperventilation or operational administration of bicarbonate to a pH below 7, 60; - Use of corticosteroids is controversial, they can produce more side effects (hypertension, hyperglycemia, infection) than benefits; - Administration of mannitol as osmotic agents is controversial.
Hemorrhage and cerebral infarctions are catastrophic results of asphyxia insult and tried to prevent them taking a single dose of phenobarbital 40 mg / kg immediately after the insult antioxidant effects attributed to asphyxia due to phenobarbital in these situations. Other antioxidants used: ascorbic acid that inhibit NMDA receptors in a dose of 100 mg / kg allopurinol (an eliminator of free radicals) 160 mg / kg, indomethacin, 0, 1 mg / kg in the first hours after the episode of asphyxia, to 4:00, inhibits the production of free radicals, vitamin E, 30 IU / kg / day for 3 days. It can manage and Ca channel blockers MK-801 - providing protection asphyxia after brain injury 95% of cases, but with high toxicity. Magnesium sulfate is a receptor site inside the channel for Ca and protect hypoxic-ischemic brain injury by a mechanism similar compounds MK-801, magnesium sulfate is given if up to one hour after asphyxia.
In the treatment of seizures, the first intention to use sodium phenobarbital given intravenously in 20 mg / kg loading dose, but we may repeat dose up to a total dose of 40 mg / kg, followed by a maintenance dose of 3 mg / kg 12 hours or even 24 hours. In the absence of phenobarbital sodium phenobarbital is used with im administration Clonazepamul used as a second cover, 100 mg / kg loading dose followed by continuous iv infusion of 10 mcg / kg / hour. Other anticonvulsants that can be taken are: diazepam 0, 1-0, 3 mg / kg loading dose, take the risk of cardiopulmonary arrest and phenytoin, 20 mg / kg loading dose, followed by a maintenance dose of 10 mg / kg. Anticonvulsants be interrupted if neurological examination is normal and EEG showed no changes.
Treatment of renal impairment provides treatment of acute renal failure, it is common pathology is caused by bone marrow necrosis, acute cortical necrosis or bone marrow or renal vein thrombosis. Correction fluid and electrolyte therapy are usually sufficient, with a single dose of furosemide 1 mg / kg / dose, after correction fluid and possibly blood pressure support with dopamine 2 mcg / kg / min. Very rarely reach peritoneal dialysis.
Treatment consists of cardiac sequelae: fluid restriction, operational administration of oxygen, control of acidosis, administration of cardiotonic agents such dopamine and dobutamine. It begins with doses of 5-10 mcg / kg / min dopamine, leading to 15-20 mcg / kg / min and very rarely in doses of 30 mcg / kg / min required to support blood pressure. Sometimes it is necessary to use continuous infusion dobutamine between 5-20 mcg / kg / min, in combination with dopamine. You can also use the beta1 and beta2 agonist izoproterenolul treat posthipoxice cardiomyopathy in premature infant, in doses of 0, 05-0, 50 mcg / kg / min. Refractory hypotension responds to medical treatment with epinephrine 0, 05-0, 50 mcg / kg / min. Pulmonary hypertension is treated with Na nitroprusside, and positive results have congestive heart failure by administration of digoxin 20-25 mcg / kg (50% of the first Admin dose followed by two doses of each 25% of the dose every 8 hours) followed by maintenance dose representing 20% of loading dose. Digoxin is contraindicated in infants with asphyxia who highlight the hypertrophic cardiomyopathy (infant of diabetic mother).
Pulmonary complications (pulmonary hypertension, pneumothorax, hyaline membrane disease, meconium aspiration) requires specific treatments.
Treatment of hematologic complications poliglobuliei provide therapy, is a common complication of asphyxia is frequently associated with increased pulmonary resistance. Therapy can be done with the administration of fluids intravenously or exchange transfusion with fresh frozen plasma (depending on hematocrit values) to maintain venous hematocrit to 45-50%.

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