| ID | 355 |
|---|---|
| Name | ASPHYXIA NEONATORUM Or, PERINATAL ASPHYXIA (Birth Asphyxia) |
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| Management | Management: A. Perinatal monitoring: When the patient is in the labour room, monitoring of the fetal heart rate, ultrasound study, fetal scalp pH etc. are very important to know the fetal condition, and progress of labour. These will guide to take decision about to perform cesarian section, augment vaginal delivery or to allow progress of normal labour. B. Delivery room treatment: Most of the babies with normal delivery do not require any resuscitation, and establish spontaneous respiration. But, about 5-10% of the newborns require resuscitative intervention to establish normal cardiorespiratory function. The goals of neonatal resuscitation are to prevent the morbidity and mortality associated with hypoxic-ischemic tissue (brain, heart, kidney) injury and to reestablish adequate spontaneous respiration and cardiac output. The steps of neonatal resuscitation: A newborn infant who requires resuscitation should be placed under a radiant heater and the head and whole body of the baby should be wiped to keep dry and prevent loss of body temperature. The steps of neonatal resuscitation include and follow ABCs- 1. Airway opening by suctioning and if necessary performing endotracheal intubation. 2. Breathing initiation by using tactile stimulation or positive-pressure ventilation. 3. Maintaining circulation with chest compression and medications (if necessary). 1. Airway opening: Positioning: Lay the baby on his back. Place a small roll of cloth under the shoulder so that the face is in line with the body. This is the ‘neutral position’ which means that the neck should be neither flexed nor extended. Hold the head with both hands. With fingers lift the jaw forward by pushing gently the jawbone at its angle. This is ‘jaw thrust’. Both the ‘neutral position’ & ‘jaw thrust’ are needed to open the airway. Airway clearence by nasopharyngeal suction: The air passages should be cleared by suction of the oral cavity, oropharynx and nose. Electric suction machine can be used carefully for this purpose where facilities are available, or a mucus extractor can also be used for the same purpose; the later can be made locally by means of a portion of a saline-set-tube and a rubber adaptor and is used by the mouth of the operator in extracting out mucus from airways. Cotton should be used in clearing mouth. Excessive and forceful suction, especially by an electric suction apparatus, may lead to mucosal damage, bleeding & reflex bradycardia. If the baby cries loudly and moves all extremities, nothing further needs to be done immediately. After spontaneous respiration has been established, it is a sound practice to raise the head above the feet. Baby then should be covered and kept warm. (Most of the babies with normal delivery do not require nasopharyngeal suction. So, suction should not be a routine practice, because it may create problems in healthy babies). 2. Breathing initiation (inflation breathing): If respiration has not been established spontaneously, breathing should be initiated by tactile stimulation or PPV with a bag and mask or through ET tube. Traditionally oxygen has been used for resuscitating babies at birth. However, now it is acknowledged that the newborn can be effectively resuscitated by bag and mask ventilator with air. A neonatal ambu bag (350ml volume) is usually used for this purpose. Blow-off valve must be kept open. Choose a mask that fits appropriately over the baby’s mouth and nose and then give 5 long slow inflation breaths with bag and mask, each lasting for at least 2 seconds. Now check if the heart rate is faster than before, if it is faster, continue with another 5 inflation breaths. Hopefully the heart rate will now increase quickly to more than 100 beats per minute and the baby will soon start to breathe. Once the heart rate is more than 100 beats per minute continue ‘bagging’ the baby at about 30 breathes per minute, until the baby is breathing regularly by himself. If heart rate after the second set of inflation breaths is still slow, go back and check that whether the airway has been opened properly, and give another 5 inflation breaths. Make sure that the chest is moving with each inflation breath. If the chest is really moving well but the heart rate still slow (less than 100 beats per minute)- start chest compressions. Indications of intubation:17 1. Prolonged apnea. 2. Apgar < 3 at 1 min. 3. Inadequate response to bag and mask ventilation. 4. Tracheal suctioning is required e.g for prevention of meconium aspiration in presence of thick meconium. 5. Need for prolonged ventilations in premature baby or significant respiratory distress. 6. Surfactant administration. Technique of endotracheal intubation:17 1. The baby should lie supine on a flat surface with a folded towel kept under shoulders, so that the neck is fully extended and the head is near the edge of the resuscitation table. 2. If the infant is atonic and if the tongue falls back and obstruct the air passage, a small airway tube is inserted in the baby’s mouth. 3. The operator should hold the ‘infant laryngoscope1 with straight blade in his left hand, and insert in the nasopharynx as far as the epiglottis, by displacing the tongue to one side. At the same time he should gently displace the cricoid cartilage backwards by the little & ring fingers of his left hand, so as to occlude the esophagus. (Size of laryngoscope-3.5 mm for full term or >2 kg, 3.0 mm for 1-2 kg, 2.5 mm for<l kg). 4. At this stage, the glottis area (by seeing the vocal cords) is cleared by suction catheter which is held in the right hand of the operator. The catheter is then placed aside and endotracheal tube is picked up and is then gently inserted by the right hand through the larynx upto carina of the trachea. 5. The secretions are now sucked out from the larynx and trachea by passing a thin catheter through the endotracheal tube. If necessary, intermittent positive pressure ventilation (IPPV) should be carried out either with a bag or by a mechanical respirator. If intubation fails- Intennittent positive pressure ventilation can be effectively achieved with a tight fitting mask and bag. During this procedure, upper airways must be cleared off any debris; glossoptosis should be safe guarded by posterior compression of cricoid cartilage. When bag and mask are unavailable- Mouth-to-mouth breathing can be imparted and ensuring that one’s oral rather than the tracheal or alveolar air is blown into the infant. 3. Maintaining circulation by chest compression & medication: Chest compression (Thumbs method): Grip the baby’s chest with both hands placing the thumbs on the sternum just below an imaginary line drawn between the two nipples (compression area is the lower third of the sternum) and use the fingers to support the infant’s back. Compress the chest l/2 to 5 inches, between sternum and spine. Press down slowly but firmly and then rapidly release the pressure. After every 3 compressions refill the chest with air from ambu bag. In this way provide- 3 compressions- one breathe 3 compressions- one breathe 3 compressions- one breathe (three cycles). Then check the heart rate to see if it is faster. If the heart rate is now fast (100 or more beats per minute)- stop chest compressions but continue ‘bagging’ the baby at about 30 breaths per minute until the baby starts to breathe regularly for himself. If the heart rate is improving but still less than about 100 beats per minute, give another 3 cycles of cardiac massage and then check again. If the heart rate is still not improving, go back and check each step again- - whether the airway is opened properly ? - whether the chest is properly inflated with each inflation breath? - whether chest compression is properly done ? - whether the blood clots, meconium, mucus is blocking the throat ? (This can be removed by suction or finger). Medications: If after opening the airway and chest moving properly with inflation breathes and giving good chest compressions the baby dose not respond, drugs (NaHCo3, adrenaline, 10% dextrose) may be used. But most babies who respond to drugs either die or servive with severe handicap. 1. Adrenaline (1:1000)- dilute 1ml of adrenaline with 9ml of distilled water & give 0.1-0.3ml/kg/dose by i.v route. 2. NaHCO3 (7.5%)- Those infants who are apnoeic at 1 minute or when ventilation is unsatisfactory even at 5 minutes should be administered 5-10ml (or 1 ml/kg) of 7.5% sodium bicarbonate being diluted with equal vol of i.v fluid intravenuosly. Sodium bicarbonate should be administered only when respiration has been established. Symtomatic 4ml/kg, Asymptomatic 2ml/kg 3. Dextrose (10%)-10% dextrose in aqua 2-4ml/kg may be given by i.v route to correct hypoglycemia. 4. Vitamin K Img i.m is given to all babies born with birth asphyxia to safeguard against bleeding. 5. Naloxone- if baby is apnoeic because of maternal opiates, resuscitate the baby first & only when baby is pink & well perfused give naloxone 0.lmg/kg or 0.2mg (0.5ml) deep i.m. Action begins within 3 minutes. * Aminophylline, dexamethasone, calcium, nikethamide are of no use. B. Postnatal treatment: 1. General treatment: Fluid and nutrition should be maintained by i.v 10% dextrose, nasogastric tube feeding or oral feeding. In severe asphyxia, i.v fluid should be given. 2. Treatment of hypoxic-ischemic brain injury: i. Temperature, O2 and CO2 should be kept in the normal range by O2 or PPV. ii. Normal BP should be maintained. 3. The blood glucose should be kept at 75-100mg/dl to provide adequate substrate for the brain. 4. Serum calcium level should be maintained at normal range. 5. Seizures: Seizures occur in about 50% of infants with hypoxic-ischemic encephalopathy (HIE), characteristically on the first or second day, usually in stage2. 3. Reduction of cerebral oedema- Restriction of daily fluid requirement to two-thirds of the normal daily requirement; use of glucocorticosteroids (controversial); and hypertonic solution, such as 20% mannitol are some of the measures utilised for effective control of cerebral oedema. 4. Control of seizures- When seizures are diagnosed, phenobarbital should be loaded slowly, 20mg/kg i.v to be followed by maintenance dose of 5-6mg/kg per day. If seizures persist, phenytoin may be administered slowly as a second drug (20mg/kg i.v as a loading dose followed by 4-8mg/kg per day as a maintenance dose). One should ascertain the metabolic derangements that may complicate asphyxia and cause seizures (e.g hypoglycemia, hypocalcemia, hyponatremia, and pyridoxine dependency seizures), these should be treated. If seizures persist, a benzodiazepine (e.g lorazepam 0.05 to 0.10mg/kg per dose i.v may be given as a third drug). If vascular access can not be achieved, rectal diazepam, or paraldehyde can be given. When the infant’s condition has been stable for 3 to 4 days, all anticonvulsants are weaned except phenobarbital. If seizures have resolved, if neurological findings are normal, and if the ECG is normal, anticonvulsants are stopped in the neonatal period (14 days of life). If this is not the case, anticonvulsants are continued for 1 to 3 months. If the neurologic findings are then normal with no recurrent seizures, phenobarbital is tapered over 4 weeks. 5. Intracranial hemorrhage- Primary subarachnoid hemorrhage are usually asymptomatic and generally requires no therapy. The management of PVH (periventricular hemorrhage)/IVH (intraventricular hemorrhage) consists of supportive therapy and serial lumber punctures for massive bleeds in order to prevent ventricular dilatation. Administration of phenobarbitone in the first few days of life is also stated to be helpful in prevention of PVH/IVH in premature infants. More recently ethamsylate has been found to be helpful in prevention of periventricular hemorrhage (PVH) by- i. reinforcing the capillary polymerisation of its constituent hyaluronic acid, ii. by increasing platelet adhesiveness, thus maintaining the integrity of the capillary walls by platelet occlusion of endothelial lacune. Complications: The neurological sequele presents as CP and the specific types are pyramidal: spastic quadriplegia usually associated with mental retardation and epilepsy, spastic diplegia, hemiplegia. Extrapyramidal symptoms include dystonia and choreoathetoid types. Auditory, visual or language difficulties reflect more extensive parasagital brain injury. |
| Introduction | Birth asphyxia (or asphyxia neonatorum, or perinatal asphyxia) can be defined as an insult to the fetus or newborn infant due to lack of oxygen (hypoxia) and/or a lack of perfusion (ischemia) to various organs which will manifest as difficulty in establishing spontaneous respiration on the part of the newborn baby evident by delayed cry after birth. This is the most common neonatal problem involving the emergency efforts of both the obstetrician & pediatrician. Management of this neonatal emergency requires a sound understanding of the problem itself & its etiological factors. |
| History | |
| Etiology | Etiology: A. Antenatal factors- 1. Maternal- i. Pre-eclampsia ii. Eclampsia, iii. Hypo- or hypertension iv. Accidental hemorrhage v. Prematrue seperation of placenta vi. C.C.F. vii. pneumonia, viii. Bronchitis & emphysema ix. Intrauterine infections. 2. Foetal- i. Rh. incompatibility ii. Foetal hemorrhage associated with placenta previa iii. Foeto-fetal or foeto-matemal transfusions iv. Abnormal presentation v. Prolapse or knotting of the umbilical cord. 3. Drugs used for the relief of pain during labour process- i. Pethidine ii. Morphine iii. Hyoscine iv. Inhalation anesthesia etc. B. Natal & postnatal factors- 1. Maternal- i. Prolonged obstructed labour ii. Instrumental delivery (by forceps or ventouse extraction) 2. Foetal- i. Prematurity ii. Meconeum aspriation iii. Raised intracranial pressure due to hemorrhage or cerebral oedema iv. Severe anemia due to hemorrhage or hemolytic disease, v. Shock in severe infection, massive blood loss, intracranial or adrenal hemorrhage, vi. Congenital abnormalities e.g pulmonary or heart diseases, laryngeal web, diaphragmatic hernia. |
| Clinical Features | Clinical features: Prenatal findings: If a fetus becomes hypoxic in the prenatal stage of the pregnancy, the sings usually become apparent a few minutes to a few days before delivery. Such as slow fetal heart rate, weak fetal movement. At delivery, the sign of fetal dis tress may be evidenced by meconium staining of amniotic fluid. Postnatal findings & evaluation of severity: At delivery the baby may present with primary or secondary apnea. Therefore, after receiving the baby, the first critical decision is to evaluate the severity of depression with the help of the ‘Apgar score’. This will dictate the course of further management such as resuscitation & other measurements. Apgar score: Apgar score provides therapeutic guidelines for managing an asphyxiated baby at birth. One-minute Apgar score usefully predicts immediate neonatal outcome of the baby, while 5-minute or later Apgar score is fairly predictive of future mental prognosis of such infant. So Apgar score at 5 min. is more inportant than at 1 min. Table : Apgar scoring system* Clinical feature Score 0 Score 1 Score 2 Appearance (color) Blue or pale Body pink, Pink all over Limbs blue Pulse (heart rate) Nil <100/min >100/min Grimace (response to Nil Grimace or Cry or Sneezing catheter put into nostril) Feeble cry Activity and tone Limp Some flexion Active of limbs movements Respiration Nil Slow, Irregular Good, Strong cry * After Professor Virginia Apgar, Anesthetist, New York. 1. A total score of 10 indicates an infant in optimum condition. A mortality rate of 15% may be expected when the score is 2 or less. 2. It is now a common practice to repeat the ‘Apgar score’ at 5 minutes, 10 minutes after birth. |
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