At what Apgar score at 5 minutes after birth should resuscitation be initiated?
Aliyu, I., Lawal, T. O., & Onankpa, B. (2018). Hypoxic-ischemic encephalopathy and the Apgar scoring system: The experience in a resource-limited setting. Journal of Clinical Sciences, 15(1), 18.
Newborn infants normally start to breathe without assistance and often cry after delivery. By 1 minute most infants are breathing well. If an infant fails to establish adequate, sustained respiration after birth, the infant is said to have NEONATAL ASPHYXIA. Show NEONATAL ASPHYXIA IS DEFINED AS THE FAILURE OF AN INFANT TO CRY OR BREATHE WELL AFTER DELIVERY Neonatal asphyxia is an important cause of neonatal death if not managed correctly. 16-2 WHAT IS HYPOXIA? Hypoxia is defined as TOO LITTLE OXYGEN IN THE CELLS OF THE BODY. Hypoxia may occur in the fetus or the newborn infant. If the placenta fails to provide the fetus with enough oxygen, hypoxia will result and cause fetal distress. Similarly, with failure to breathe well after delivery (i.e. neonatal asphyxia) the infant will develop hypoxia. As a result of hypoxia the heart rate falls, central cyanosis develops and the infant becomes hypotonic (floppy) and unresponsive. Note that neonatal asphyxia and hypoxia are not the same although they often occur together. Fetal hypoxia may result in neonatal asphyxia while neonatal asphyxia will result in hypoxia if the infant is not rapidly resuscitated. HYPOXIA IS DEFINED AS TOO LITTLE OXYGEN IN THE CELLS OF THE BODY 16-3 WHAT IS THE APGAR SCORE? The Apgar score is a method of assessing an infant's clinical condition after delivery. The Apgar score is based on 5 vital signs:
Each vital sign is given a score of 0 or 1 or 2. A score of 2 is normal, a score of 1 is mildly abnormal and a score of 0 is severely abnormal. The individual vital sign scores are then totalled to give the Apgar score out of 10. The best possible Apgar score is 10 and the worst 0. An infant with a score of 0 shows no sign of life. Normally the Apgar score is of 7 to 10. Infants with a score between 4 and 6 have moderate depression of their vital signs while infants with a score of 0 to 3 have severely depressed vital signs and are at great risk of dying unless actively resuscitated. Due to the presence of peripheral cyanosis in most infants at delivery, it is unusual for a normal infant to score 10 at 1 minute. By 5 minutes most infants will have a score of 10. If the Apgar score is guessed and not correctly assessed, too high a score is usually given. *** The Apgar score is named after the late Dr. Virginia Apgar, an anaesthetist, who described the scoring method in 1953. The method of assessing the Apgar score is described in skills workshop 16. 16-4 WHEN SHOULD YOU DETERMINE THE APGAR SCORE? The Apgar score should be performed on all infants at 1 minute after birth to record the infant's clinical condition and to assess whether the infant requires resuscitation. If the 1 minute Apgar score is below 7, then the Apgar score should be repeated at 5 minutes to document the success or failure of the resuscitation efforts. If the 5 minute Apgar score is still low, it should be repeated every 5 minutes until a normal Apgar score of 7 or more is achieved. In many hospitals, the Apgar score is often routinely repeated at 5 minutes even if the 1 minute score was normal. This is not necessary and the infant should rather be handed to the mother. 16-5 WHAT CAUSES A LOW APGAR SCORE? There are many causes of a low Apgar score. These include:
Note that fetal distress due to hypoxia during labour is only one of the many causes of neonatal asphyxia. However, neonatal asphyxia will result in hypoxia after delivery if the infant is not rapidly resuscitated. It is important to always try and find the cause of a low Apgar score. 16-6 WHAT IS INFANT RESUSCITATION? Resuscitation is a series of actions taken to establish normal breathing, heart rate, colour, tone and activity in an infant with depressed vital signs (i.e. a low Apgar score). 16-7 WHICH INFANTS NEED RESUSCITATION? All infants who do not breathe well after delivery (i.e. infants with neonatal asphyxia) or have a 1 minute Apgar score below 7 need immediate resuscitation. The lower the Apgar score the more resuscitation is usually needed. Any infant who stops breathing or has depressed vital signs at any time after delivery or in the nursery also requires resuscitation. ALL INFANTS WITH A 1 MINUTE APGAR SCORE BELOW 7 REQUIRE RESUSCITATION 16-8 CAN YOU ANTICIPATE WHO WILL NEED RESUSCITATION AT BIRTH? Yes. The following clinical situations often lead to the delivery of an infant with neonatal asphyxiated and a low Apgar score at 1 minute:
Remember that any infant can be born with neonatal asphyxia without prior warning. It is essential, therefore, to be prepared to resuscitate any newborn infant. Anyone who delivers an infant must be able to perform resuscitation. ANY INFANT CAN HAVE NEONATAL ASPHYXIA WITHOUT WARNING SIGNS DURING LABOUR 16-9 WHAT EQUIPMENT DO YOU NEED FOR INFANT RESUSCITATION? It is essential that you have all the basic equipment needed for simple infant resuscitation. The equipment must be in working order and immediately available. The equipment must be checked daily. A warm, well lit corner of the delivery room should be available for resuscitation. A heat source, such as an overhead radiant warmer, is needed to keep the infant warm. A good light, such as an angle poise lamp, is required so that the infant can be closely observed during resuscitation. The following essential equipment must be available in the delivery room:
*** Ampoules of 4% sodium bicarbonate and ampoules of 1:1000 adrenaline. 16-10 HOW SHOULD YOU STIMULATE RESPIRATION IMMEDIATELY AFTER BIRTH? After birth all infants must be quickly dried in a warm towel and then placed in a second warm, dry towel before starting resuscitation. This prevents rapid heat loss due to evaporation. Handling and rubbing the newborn infant with a dry towel is usually all that is needed to stimulate the onset of breathing. Gently flicking under the infant's feet may be helpful in stimulating breathing. Stimulation alone will start breathing in most infants. There is no need to smack newborn infants. Infants who breathe well at delivery should NOT be routinely suctioned as suctioning sometimes causes apnoea. Infants born by caesarean section also need not be routinely suctioned. IT IS NOT NECESSARY TO ROUTINELY SUCTION THE MOUTH AND NOSE OF INFANTS AFTER DELIVERY 16-11 HOW DO YOU RESUSCITATE AN INFANT? If the infant fails to respond to stimulation, then the infant must be actively resuscitated. The most experienced person, irrespective of rank, should resuscitate the infant. However, all staff who conduct deliveries must be able to resuscitate infants. It is very helpful to have an assistant. There are 4 main steps in the basic resuscitation of a newborn infant. They can be easily remembered by thinking of the first 4 letters of the alphabet, i.e. "ABCD" - AIRWAY - BREATHING - CIRCULATION - DRUGS. STEP 1. OPEN AND CLEAR THE AIRWAY.
If stimulation, positioning and suctioning fail to start breathing, the infant needs mask ventilation. Do not waste time by giving oxygen without also applying mask ventilation. VENTILATION IS THE MOST IMPORTANT STEP IN NEWBORN RESUSCITATION STEP 2. START THE INFANT BREATHING BY PROVIDING ADEQUATE VENTILATION.
MOST INFANTS CAN BE ADEQUATELY VENTILATED WITH A BAG AND MASK The method of mask ventilation and tracheal intubation is described in skills workshop 16. STEP 3. OBTAIN A GOOD CIRCULATION WITH CHEST COMPRESSIONS. Apply chest compressions (external cardiac massage) at about 80 times a minute if the heart rate remains below 60 beats per minute after effective ventilation has been started. Place the fingers of one or two hands under the infant's back and press on the lower half of the sternum with your thumb or thumbs. Usually two chest compressions is followed by a breath. The method of giving cardiac massage is described in skills workshop 16. STEP 4. DRUGS TO REVERSE PETHIDINE AND MORPHINE. If the mother has received either pethidine or morphine during the 4 hour period before delivery, the infant's poor breathing may be due to narcotic depression. If so, the depressing effect of the analgesia on respiration can be rapidly reversed with Narcan (a 1 ml ampoule contains 0,4 mg naloxone). Narcan 0,1 mg/kg (i.e. 0,25 ml/kg) can be given by intramuscular injection into the anterolateral aspect of the thigh. Do not use Neonatal Narcan as this preparation requires too big a volume. Narcan will not help resuscitate an infant if the mother has not received a narcotic analgesic during labour, or has only received a general anaesthetic, barbiturates or other sedatives. *** Narcan acts more rapidly if injected directly into the umbilical vein or if given down the endotracheal tube. Flumazenil (Anexate) will reverse the depressant effect of benzodiazepines such as diazepam (Valium). *** With experience and further training, additional drugs can be given if the above steps fail to resuscitate the infant:
A summary of the method of resuscitating a newborn infant is shown in flow diagram 16-1. The 4 steps in resuscitation are followed step by step until the 3 most important vital signs of the Apgar score have returned to normal:
16-12 DOES THE MECONIUM STAINED INFANT NEED SPECIAL CARE? Yes. All infants that have meconium stained amniotic fluid (liquor) at birth need special care to prevent severe meconium aspiration. Whenever possible all these at risk infants should be identified before delivery, especially infants with thick meconium in the amniotic fluid. 16-13 WHY DOES THE MECONIUM STAINED INFANT NEED SPECIAL CARE? As a result of hypoxia before delivery, the fetus may make gasping movements and also pass meconium. Meconium can, therefore, be sucked into the upper airways together with amniotic fluid. Fortunately most of the meconium is unable to reach the fluid filled alveoli of the fetus. Only after delivery, when the infant inhales air, does meconium enter the small airways and alveoli. Meconium contains enzymes from the fetal pancreas that can cause severe lung damage and even death if inhaled into the alveoli after delivery. Meconium also obstructs the airways. *** Meconium often burns the infant's skin and digests away the infant's eye lashes! Therefore, imagine the damage meconium can cause to the delicate lining of the bronchi and alveoli. 16-14 HOW CAN YOU PREVENT MECONIUM ASPIRATION AT VAGINAL DELIVERY? Many cases of meconium aspiration syndrome can be prevented with the correct care of the infant during delivery. A suction apparatus and a F 10 end hole catheter must be ready at the bedside. If possible, the person conducting the delivery should have an assistant to suction the infant's mouth when the head delivers. After delivery of the head, the shoulders should be held back and the mother asked to pant to prevent delivery of the trunk. The infant's face is then turned toward the assistant so that the mouth and pharynx can be well suctioned. Only when no more meconium can be cleared, should the infant be completely delivered. If the infant cries well after delivery, no further resuscitation or suctioning is needed. However, some infants develop apnoea and bradycardia as a result of the suctioning and, therefore, need ventilation after delivery. If an infant needs ventilation, the pharynx should again be suctioned, preferably under direct vision using a laryngoscope, before ventilation is started. If the infant is intubated, direct suction can be applied to the endotracheal tube. Withdraw the endotracheal tube while applying suction Repeat until no more meconium is obtained. This aggressive method of suctioning is very successful in preventing severe meconium aspiration but should not be used when resuscitating infants that are not meconium stained. MECONIUM STAINED INFANTS MUST BE SUCTIONED BEFORE DELIVERY OF THE SHOULDERS 16-15 HOW CAN YOU PREVENT MECONIUM ASPIRATION AT CAESAREAN SECTION? When a meconium stained infant is delivered by caesarean section, the mouth and pharynx must be suctioned with a F10 end hole catheter, BEFORE the shoulders are delivered from the uterus. After complete delivery, move the infant immediately to the resuscitation table. If the infant does not breathe spontaneously, further suctioning under direct vision is needed before stimulating respiration or applying ventilation. Infants who breathe well after delivery do not need to be suctioned again. 16-16 WHEN IS FURTHER RESUSCITATION HOPELESS? Every effort should be made to resuscitate all infants that show any sign of life at delivery. The severity of neonatal asphyxia at 1 and 5 minutes is not a good indicator of the likelihood of hypoxic brain damage or the possibility of an unsuccessful resuscitation. If the Apgar score remains low after 5 minutes, efforts at resuscitation must be continued. However, if the infant has not started to breathe, or only gives occasional gasps by 20 minutes, the chance of death or brain damage is extremely high. The exception is when the infant is sedated by maternal drugs. It is preferable if an experienced person decides when to abandon further attempts at resuscitation. *** Some people claim that resuscitating infants with severe neonatal asphyxia is contra-indicated as they survive with brain damage. Research has indicated that this claim is not correct as the majority of severely neonatal asphyxiated infants that are aggressively resuscitated and survive recover completely. 16-17 WHAT POST RESUSCITATION CARE IS NEEDED? All infants that require resuscitation must be carefully observed for at least 4 hours. Their temperature, pulse and respiratory rate, colour and activity should be recorded and their blood glucose levels checked. Keep these infants warm and provide fluid and energy either intravenously or orally. Usually these infants are observed in a closed incubator. Do not bath the infant until the infant has fully recovered. If the infant has signs of respiratory difficulty or is centrally cyanosed in room air after resuscitation, it is essential to provide oxygen while the infant is being moved to the nursery. Some infants may even require ventilation during transport. Careful notes must be made describing the infant's condition at birth, the resuscitation needed and the probable cause of the neonatal asphyxia. 16-18 WHAT CARE SHOULD YOU GIVE TO MECONIUM STAINED INFANTS IN THE NURSERY? All heavily meconium stained infants should be observed in the nursery for a few hours after delivery as they may show signs of hypoxic damage or meconium aspiration syndrome. Most meconium stained infants have swallowed meconium before delivery. Meconium is a very irritant substance and causes meconium gastritis. This results in repeated vomits of meconium stained mucus. Infants with lightly meconium stained amniotic fluid who appear well after delivery can be kept with their mothers. Meconium gastritis may be prevented by washing out the stomach tube with 2% sodium bicarbonate (mix 4% sodium bicarbonate with an equal volume of sterile water). Five ml of 2% sodium bicarbonate is repeated injected into the stomach via a nasogastric tube and then aspirated until the gastric aspirate is clear All heavily meconium stained infants should have a stomach washout on arrival in the nursery. This should be followed by a feed of colostrum. Routine stomach washouts in preterm infants or infants born by caesarean section are not needed. *** Colostrum contains phagocytic cells that ingest any meconium that remains in the stomach. This reduces the chance of further vomiting. A STOMACH WASHOUT IS ONLY NEEDED IF THE INFANT IS COVERED WITH THICK MECONIUM 16-19 WHAT IS THE DANGER OF FETAL DISTRESS DUE TO PRENATAL HYPOXIA? If the cells of the fetus do not receive adequate oxygen during pregnancy or labour, many organs may be damaged. This may result in either:
16-20 WHAT ORGANS ARE COMMONLY DAMAGED BY HYPOXIA?
*** At the onset of hypoxia, blood is shunted away from the kidneys, gut and lungs to the brain and heart. This mechanism to protect the brain and heart may cause ischaemic damage to the kidneys, gut and lungs. The increased blood flow to the brain may cause intraventricular haemorrhage in preterm infants. With severe, prolonged hypoxia, cardiac output falls and as a result the brain and myocardium may also suffer ischaemic damage. HAEMATURIA IN THE NEWBORN INFANT IS A USEFUL CLINICAL MARKER OF PRENATAL HYPOXIA 16-21 WHAT DAMAGE IS DONE TO THE BRAIN BY HYPOXIA? Different types of brain damage can occur depending on the gestational age of the fetus and the severity of the hypoxia:
*** REFERENCES The method of resuscitation described is that advocated by the American Academy of Pediatrics and the American Heart Association:
CASE PROBLEMS CASE 1 After a normal pregnancy, an infant is born by elective caesarian section under general anaesthesia. The indication for the caesarean section is two previous caesarean sections for cephalopelvic disproportion. Immediately after delivery the infant is dried and placed under an overhead radiant warmer. At 1 minute after birth the infant has a heart rate of 80 beats per minute, gives irregular gasps, has blue hands and feet but a pink tongue, has some muscle tone but does not respond to stimulation. At 5 minutes the infant has a heart rate of 120 beats per minute and is breathing well. The tongue is pink but the hands and feet are still blue. The infant moves actively and cries well. 1. What is the infant's Apgar score at 1 minute?
2. Does this infant have neonatal asphyxia? Give your reasons.
3. What is the probable cause of the neonatal asphyxia?
4. What should be the first 2 steps in resuscitating this infant?
5. What is this infant's Apgar score at 5 minutes?
6. Why is this infant very unlikely to have suffered brain damage due to hypoxia?
7. What should be the management of this infant after resuscitation?
CASE 2 After fetal distress has been diagnosed, an infant is delivered by a difficult vacuum extraction. At delivery the infant is covered with thick meconium. The infant starts to gasp before 1 minute. Only then are the mouth and pharynx suctioned for the first time. The Apgar score at 1 minute is 3. By 5 minutes the Apgar score is 6. 1. What are the probable causes of the low 1 minute Apgar score ?
2. What mistake was made with the management of this infant?
3. What size catheter would you have used to suction this infant's mouth and pharynx?
4. Should this infant be given a bath and stomach washout in labour ward after it starts to breathe spontaneously?
5. What 2 complications is this infant at high risk of?
CASE 3 A woman with an abruptio placentae delivers at 32 weeks. Before delivery the fetal heart rate was only 80 beats per minute. The infant appeared dead at birth but was intubated and ventilated. Cardiac massage was also given. The 1 minute Apgar score was 2. Despite further efforts at resuscitation, the Apgar score at 5, 10, 15 and 20 minutes remained 2. 1. What is the probable cause of neonatal asphyxia in this infant?
2. Why is it possible to successfully resuscitate some infants that appear dead at birth?
3. What is the significance of the low Apgar scores at 5, 10, 15 and 20 minutes?
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