32. RESUSCITATION OF THE NEWBORN INFANT

The normal newborn does not require resuscitation after a normal birth and will begin to breathe within a few seconds of birth and quickly establish regular breathing. The first breath of the newborn is important to establish normal respiratory and cardiovascular function. The newborn that does not breathe spontaneously within one minute is abnormal.

After birth the baby should be placed on a dry, warm towel, placed under a heater and dried. (It is essential to conserve the baby’s body heat during a difficult resuscitation). Gently aspirating the mouth and nose should clear the baby’s airway. If suction is not available the baby should be maintained with the head down to allow drainage of secretions. Suction is not necessary if the baby has been born vaginally and is vigorous and crying.

Most newborns that do not cry will begin breathing after gentle stimulation by drying. Simple airway management can prevent hypoxia.

Always check the equipment before the baby is born.

Predicting the Need for Resuscitation

Often the need for resuscitation can be predicted. Certain obstetric situations may warn the anaesthetist that the newborn may need resuscitation including:

prolonged labour, cephalopelvic disproportion, breech delivery, shoulder dystocia, difficult forceps delivery, prolapsed umbilical cord

maternal haemorrhage, placenta praevia, maternal infection, maternal diabetes

foetal distress, prematurity, meconium liquor

opioids or other respiratory depressant drugs given close to the time of delivery

Assessment of the Newborn

The clinical condition of the infant will indicate what resuscitation is needed.

The anaesthetist must make a rapid assessment of the newborn within the first 30 to 60 seconds to assess the urgency of the situation. There are four questions the anaesthetist must answer.

1.            Does the baby respond to stimulation?

2.            Is the baby breathing? (absent, irregular, regular)

3.            Is the heart rate above or below 100? 

               (listen to the heart or feel the base of the umbilical cord)

4.            Is the baby active or floppy?

5.            Is the baby pale, cyanosed or pink?

Most newborns will respond to the stimulation of birth with movement of all limbs, breathing and a heart rate over 100/min. If theses responses are absent or weak the newborn should be stimulated by gentle drying only. After initial respiratoty efforts the newborn’s breathing may pause for a few seconds before establishing respiration sufficient to maintain its heart rate greater than 100/min.

Resuscitation

The baby may be:

Normal: active baby with regular breathing and heart rate above 100 bpm and pink.
(Apgar 8 – 10).

These babies require no treatment other than drying and keeping warm.

Mild depression: occasionally breathes, heart rate above 100 bpm and good muscle tone.
(Apgar 7 – 8).

These babies need oxygen by facemask and ventilation by bag and mask (40 to 60 breathes per minute) if breathing does not become regular.

Moderate depression: absent or irregular breathing, fair muscle tone and heart rate above 100 bpm. (Apgar 3 – 6)

These babies need bag-and-mask ventilation but be prepared to intubate if the heart rate slows or the baby does not become pink and active within thee minutes.

Severe depression: no respiratory or spontaneous movement, limp and pale with
heart rate less than 100 bpm. A heart rate below 100/min is a serious sign.

These babies need immediate positive pressure ventilation until the heart rate is greater than 100/min. If breathing remains inadequate and the heart rate falls below 60/min assess the adequacy of ventilation and improve if possible. Start heart compressions at a ratio of 3:1 with 90 compressions and 30 inflations/minute. If the heart rate does not improve after 30 to 60 seconds of ventilation and heart compression give adrenaline 0.1 to 0.3 ml/kg of 1:10,000 intravenously followed by a small flush. Volume expansion (10 ml/kg) should be comsidered if there is suspected blood loss, the child appears shocked or if not responding to resuscitation efforts.

Shock: if there is acute foetal blood loss, rapid replacement of the blood volume by syringe into the umbilical vein can be life saving. Use O Rh –ve blood, blood cross matched for the mother, freshly collected maternal blood or any fluid in an emergency. Give 10 to 20 ml/kg.

Airway

The most important action for resuscitation of the newborn is to obtain a clear airway and administer oxygen.

Tilting the head into a neutral position and lifting the jaw upwards can clear the newborn airway. The mouth can be cleared of secretions by gentle suctioning. Aggressive suctioning must be avoided as it can cause laryngospasm and vagal bradycardia. Intrapartum suctioning (before delivery of the shoulders) makes no difference to outcome of babies with meconium stained liquor.

If pharyngeal suctioning is required, it should be performed with a suction source of less than 100 mmHg and should not exceed more than 5 seconds or be inserted more than 5 cms.

If the amniotic fluid contains thick meconium and the infant has weak or absent respiration and decreased muscle tone, sucking meconium from the mouth and pharynx should be carried out immediately under direct laryngoscopy and if needed followed up by endotracheal intubation and suctioning of the trachea.

Self-inflating resuscitation bags or facemask T piece resuscitators must have a safety pressure release system (20 to 30 cmH20). An advantage of self-inflating resuscitation bags is that they do not need an oxygen source. (If oxygen is available it must be used. To optimise oxygenation, the self-inflating bag should have an oxygen reservoir attached. Oxygen flow should be at least 15 l/min).

Some newborns may need endotracheal intubation. Attempts at intubation must not be longer than 30 seconds.

(an endotracheal tube 0.5 size bigger and smaller should be available).

Drugs

Adrenaline may be needed if the heart rate is less than 60/min. (0.1 to 0.3 ml/kg of 1:10,000). There is insuffiecient evidence to support endotracheal adrenaline, however if used, adrenaline should be given at 30 to 100 µg/kg.

Naloxone is an opioid antagonist. If the infant is depressed from maternal morphine or pethidine give 0.01 mg/kg. Intramuscular injection is usually adequate.

Sodium bicarbonate and glucose may be given when the baby is severely depressed and resuscitation is prolonged. The use of sodium bicarbonate remains controversial. 8.4% sodium bicarbonate can be given intravenously (1 mg/kg). This dose should be diluted 1:1 with dextrose or water to make a 4.2% solution and injected slowly over 1 to 2 minutes. Glucose should only be given to patients with known hypoglycaemia (less than 2 mmol/l).

Cardiac Compressions

The best method of cardiac compression in the newborn is to place both thumbs over the lower half of the sternum with the hands encircling the body and the fingers supporting the back. The sternum is compressed 2 to 3 cm at a rate of 120/minutes. Alternative the lower half of the sternum can be compressed with the index and middle finger. This allows the anaesthetist to use only one hand.

Venous Access

Drugs may be given by a peripheral vein, umbilical vein or down the endotracheal tube.

Peripheral venous access can be very difficult in the shocked newborn. Only adrenaline should be administered by the endotracheal route and this is not supported by evidence. Naloxone may be given intramuscularly but only after establishment of adequate assisted ventilation and peripheral circulation. Intraoosseous routes are not usually used in newborns because of the availability of the umbilical vein and the fragility of the newborns bones.

Umbilical vein catheterisation is not difficult but there are potential complications. Insertion of an umbilical vein catheter should occur under sterile conditions. Having cleaned the umbilical stump a cord can be lightly tied around it. This will be tightened after the umbilical catheter is inserted. The cord should be cut leaving at least 2 cm. The umbilicus contains 2 arteries and 1 vein. The vein is usually the large thin walled structure found at 12 o’clock. This should be dilated gently. A sterile 3.5 or 5 French catheter is inserted 2 to 4 cm beyond the abdominal wall (Long term umbilical catheters must be carefully positioned using X-ray). It should advance without any resistance and be gently aspirated for blood. (Sometimes blood cannot be aspirated from a correctly placed catheter because the vein is collapsing. Flush the catheter with 2 ml of normal saline and aspirate more gently). Tighten the cord around the base of the umbilical stump and suture the catheter to the base of the cord.

APGAR SCORE: points are awarded for each of five criteria.

Score

For example, a newborn with a heart rate over 100 beats per minute, that is making slow irregular respiratory effort and is active and blue with absent reflex would have an APGAR score of 5.