3: Resuscitation of the Newborn

About 10% of all newborns require some assistance to begin breathing after birth, and ~1% require extensive resuscitation efforts. Newborn resuscitation cannot always be anticipated in time to transfer the mother before delivery to a facility with specialized neonatal support. Therefore, every hospital with a delivery suite should have an organized, skilled resuscitation team and appropriate equipment available (Table 3–1).

Normal transitional events at birth begin with initial lung expansion, generally requiring large negative intrathoracic pressures, followed by a cry (expiration against a partially closed glottis). Umbilical cord clamping is accompanied by a rise in systemic blood pressure and massive stimulation of the sympathetic nervous system. With onset of respiration and lung expansion, pulmonary vascular resistance decreases, followed by a gradual transition (over minutes to hours) from fetal to adult circulation, with closure of the foramen ovale and ductus arteriosus.

The asphyxiated newborn undergoes an abnormal transition. Acutely with asphyxiation the fetus develops primary apnea, during which spontaneous respirations can be induced by appropriate sensory stimuli. If the asphyxial insult persists about another minute, the fetus develops deep gasping for 4–5 minutes, followed by a period of secondary apnea, during which spontaneous respirations cannot be induced by sensory stimulation. Death occurs if secondary apnea is not reversed by vigorous ventilatory support within several minutes. Because one can never be certain whether an apneic newborn has primary or secondary apnea, resuscitative efforts should proceed as though secondary apnea is present.

Preparation for a high-risk delivery is often the key to a successful outcome. Cooperation between the obstetric, anesthesia, and pediatric staff is important. Knowledge of potential high-risk situations and appropriate interventions is essential (Table 3–2). It is useful to have an estimation of weight and gestational age (Table 3–3), so that drug dosages can be calculated and the appropriate endotracheal tube (see Table 29–1) and umbilical catheter size (Venous Access: Umbilical Vein Catheterization) can be chosen. While waiting for the infant to arrive, it is useful to think through potential problems, steps that may be undertaken to correct them, and which member of the team will handle each step. Provided there is both time and opportunity, resuscitative measures should be discussed with the parents. This is particularly important when the fetus is at the limit of viability or when life-threatening anomalies are anticipated.

The Apgar score (Appendix B) is assigned at 1, 5, and, occasionally, 10–20 minutes after delivery. It gives a fairly objective retrospective idea of how much resuscitation a term infant required at birth and the infant's response to resuscitative efforts. It is, however, not useful during resuscitation. During resuscitation, simultaneous assessment of respiratory activity and heart rate provides the quickest and most accurate evaluation of the need for continuing resuscitation.

1. Respiratory activity. Respiratory activity is assessed by observing chest movement or listening for breath sounds. If there is no respiratory effort or the effort is poor, the infant needs respiratory assistance by either manual stimulation or positive-pressure ventilation.

2. Heart rate. The heart rate is typically evaluated by listening to the apical beat or feeling the pulse by lightly grasping the base of the umbilical cord. The evaluator should tap out each beat so that all team members can hear it. If no heart rate can be heard or felt, ventilatory efforts should be halted for a few seconds so that another team member can verify this finding. Pulse oximetry is also useful for monitoring heart rate during resuscitation.

The American Heart Association (AHA) and American Academy of Pediatrics' (AAP) Textbook of Neonatal Resuscitation (6th ed., 2011) provides a widely used standard of care used in most delivery services for the resuscitation of newborns (Figure 3–1).

1. Ventilatory resuscitation

   1. General measures

      1. Suctioning. Oropharyngeal and nasal secretions should be partially removed with a brief period of suctioning using either a bulb syringe or a suction catheter if there are signs of airway obstruction or before initiation of positive-pressure ventilation.

      2. Positive-pressure ventilation. Most infants can be adequately ventilated with a bag and mask provided that the mask is the correct size with a close seal around the mouth and nose, and there is an appropriate flow of gas to the bag (Figure 3–2). A T-piece resuscitator is an alternative method to provide positive-pressure ventilation that controls peak pressure and positive end-expiratory pressure (PEEP), or continuous positive airway pressure (CPAP) (Figure 3–3). Respiratory rate should be 40–60 breaths/min, or 30 breaths/min if accompanying chest compressions. Peak pressures of 20–25 cm H₂O are usually sufficient, but initial pressures as high as 30–40 cm H₂O may be required. The stomach should be emptied during and after prolonged bag-and-mask ventilation by orogastric suctioning. The AAP and AHA recommend that blended gas be used for positive-pressure ventilation and oxygen concentration be adjusted to meet the preductal (right wrist) pulse-oximetry goals based on the age after birth (Table 3–4).

      3. Endotracheal intubation. Endotracheal intubation should be performed when indicated. However, multiple unsuccessful attempts at intubation by inexperienced persons may make a difficult situation worse. In these cases, it may be best to continue mask ventilation until experienced help arrives. An alternative to endotracheal intubation when intubation attempts are unsuccessful and mask ventilation is not effective is placement of a laryngeal mask airway (see Chapter 34). Absolute indications for aggressive ventilatory support with endotracheal intubation are difficult to list here because institutional guidelines and clinical situations vary widely. The procedure for endotracheal intubation and some general guidelines are discussed in Chapter 29.

   2. Specific measures

      1. Term infant with meconium staining. Infants born through thick meconium may aspirate this inflammatory material in utero (gasping), during delivery, or immediately after birth. The sickest of these infants have usually aspirated in utero and generally also have reactive pulmonary vasoconstriction. Gregory and associates (1974) were among the first to show that endotracheal suctioning at birth was beneficial. More recently, the AAP and the AHA recommended endotracheal suctioning when meconium is present in the amniotic fluid and the infant is not vigorous (eg, without good muscle tone, good respirations, and heart rate >100 beats/min). Clinical judgment is always important in deciding whether or not aggressive endotracheal suctioning is necessary. (Meconium aspiration is discussed in detail in Chapter 108.) A randomized multicenter trial of intrapartum suctioning (ie, suctioning before delivery of the chest) of the hypopharynx has not shown any reduction in the risk of meconium aspiration syndrome, and this procedure is no longer recommended.

         1. In nonvigorous infants (heart rate <100, poor tone, or poor respiratory effort), perform endotracheal suctioning. Do not stimulate the infant but proceed directly to intubate the trachea and apply suction directly to the endotracheal tube. Suctioning with a negative pressure of 100 mm Hg can be done directly from the wall unit via a connector (meconium aspirator) to the endotracheal tube. Suction is applied as the endotracheal tube is slowly withdrawn.

         2. If meconium has been suctioned “below the cords,” suctioning should be repeated after reintubation. Prolonged or repeated suctioning is not recommended, as it will exacerbate the preexisting asphyxia insult.

         3. The procedures just described may be continued for up to 2 minutes after delivery, but then other resuscitative measures (particularly ventilation) must be started.

         4. If meconium-stained fluid is reported at <34 weeks' gestation, one of the following situations should be suspected:

            • (a) The fetus is a growth-restricted term infant.

            • (b) The fluid may actually be purulent (consider Listeria or Pseudomonas species).

            • (c) The fluid may actually be bile stained (consider proximal intestinal obstruction).

      2. Term infant with perinatal asphyxia

         1. Initially all infants without meconium-stained amniotic fluid should be dried and have their oropharynx suctioned. If the infant is not vigorous (strong cry, good tone), a brief period of tactile stimulation by rubbing the back and/or tapping the soles of the feet can be used. Follow immediately by evaluating respirations and heart rate.

         2. A term infant with a heart rate of <100 beats/min or no spontaneous respiratory activity requires positive-pressure ventilation. If brief tactile stimulation fails to stimulate adequate respirations, positive-pressure ventilation should be initiated at 40–60 breaths/min. If this is not successful in stimulating spontaneous respiratory effort or an improved heart rate, airway patency and positioning of the mask should be confirmed and then peak-inflating pressures should be adjusted as necessary to expand the lungs. If bag-and-mask ventilation is ineffective or prolonged positive-pressure ventilation is necessary, endotracheal intubation or placement of a laryngeal mask airway is indicated. (See Chapters 29 and 34.)

      3. Preterm infant. Preterm infants weighing <1200 g often require immediate lung expansion in the delivery room.

         1. Mask continuous positive airway pressure (CPAP), administered with a T-piece resuscitator or a flow-inflating bag-and-mask system, providing a pressure of 4–6 cm water, may be sufficient to expand the lungs of a preterm infant and improve ventilation.

         2. If intubation is required, a smaller (2.5- or 3-mm internal diameter) endotracheal tube is selected.

         3. Although high peak-inflating pressures may initially be needed to expand the lungs, as soon as the lungs “open up” the pressure should be quickly decreased to as low as 20–25 cm H₂O by the end of the resuscitation if the clinical course permits.

         4. If available, one of several forms of surfactant may be administered intratracheally as prophylaxis for respiratory distress syndrome. (See Chapters 8 and 124.) However, surfactant is not considered a resuscitative medication and should be administered only to a stable neonate with a correctly placed endotracheal tube.

2. Cardiac resuscitation. During delivery room resuscitation, efforts should be directed first to assisting ventilation and providing supplemental oxygen. A sluggish heart rate usually responds to these efforts.

   1. If the heart rate continues to be <60 beats/min in spite of 30 seconds of positive-pressure ventilation, chest compression should be initiated. The thumbs are placed on the lower third of the sternum, between the xiphoid and the line drawn between the nipples (Figure 3–4). Alternatively, the middle and ring fingers of one hand can be placed on the sternum while the other hand supports the back. The sternum is compressed a third of the anteroposterior diameter of the chest at a regular rate of 90 compressions/min while ventilating the infant at 30 breaths/min, synchronized such that every 3 compressions are followed by 1 breath. The heart rate should be checked periodically and chest compression discontinued when the heart rate is >60 beats/min.

   2. An infant with no heart rate (a true Apgar of 0) who does not respond to ventilation and oxygenation may be considered stillborn. Prolonged resuscitative efforts are a matter for ethical consideration. The American Academy of Pediatrics and American Heart Association state that if there is no heart rate after 10 minutes of adequate resuscitation efforts, discontinuation of resuscitation efforts may be appropriate.

3. Drugs used in resuscitation. (See also Emergency Medications and Therapy for Neonates, inside the front and back covers, and Chapter 148 for more details.) The Textbook of Neonatal Resuscitation, 6th ed., recommends giving medications if the heart rate remains <60 beats/min despite adequate ventilation and chest compression for a minimum of 30 seconds.

   1. Route of administration

      1. The umbilical vein is the preferred route for rapid drug administration in the delivery room. A 3.5 or 5F umbilical catheter should be inserted just until blood is easily withdrawn (usually 2–4 cm); this should avoid inadvertent placement in the hepatic or portal vein. Formal umbilical vein catheterization is discussed in Chapter 44.

      2. The endotracheal tube is an alternative route for administration of epinephrine in the delivery room while vascular access is being obtained, but absorption is variable. This route may be used while vascular access is being obtained. See Chapter 29 for medications that can be administered by this route.

      3. Alternate routes of administration include peripheral venous (see Chapter 43) and intraosseous routes (see Chapter 41).

   2. Medications commonly used in neonatal resuscitation

      1. Epinephrine. Epinephrine may be necessary during resuscitation when adequate ventilation, oxygenation, and chest compression have failed and the heart rate is still <60 beats/min. This drug causes peripheral vasoconstriction, enhances cardiac contractility, and increases heart rate. The dose is 0.1–0.3 mL/kg of 1:10,000 solution given intravenously or 0.5–1 mL/kg of 1:10,000 if given by the endotracheal tube. This may be repeated every 3–5 minutes.

      2. Volume expanders. Hypovolemia should be suspected in an infant requiring resuscitation when there is evidence of acute blood loss with extreme pallor despite adequate oxygenation, poor peripheral pulse volume despite a normal heart rate, long capillary refill times, or poor response to resuscitative efforts. Appropriate volume expanders include normal saline, lactated Ringer's solution, or O-negative packed red blood cells (cross-matched against the mother's blood). All are given 10 mL/kg intravenously over 5–10 minutes.

      3. Naloxone. Naloxone is a narcotic antagonist and can be administered to an infant with respiratory depression unresponsive to ventilatory assistance whose mother has received narcotics within 4 hours before delivery. The initial corrective action is positive-pressure ventilation. One major contraindication to the use of naloxone is the newborn infant of a mother chronically exposed to narcotics. These infants should never receive naloxone because acute withdrawal symptoms may develop. The intravenous or intramuscular dosage for naloxone is 0.1 mg/kg. Two concentrations of naloxone are available: 0.4 mg/mL and 1.0 mg/mL. The dose may be repeated every 5 minutes as necessary. It should be emphasized that the half-life of naloxone is shorter than that of narcotics.

      4. Sodium bicarbonate. Sodium bicarbonate is usually not useful during the acute phase of neonatal resuscitation. Without adequate ventilation and oxygenation, it will not improve the blood pH and may worsen cerebral acidosis. After prolonged resuscitation, however, sodium bicarbonate may be useful in correcting documented metabolic acidosis. Give 1–2 mEq/kg intravenously at a rate of 1 mEq/kg/min or slower.

      5. Atropine and calcium. Although previously used during resuscitation of the asphyxiated newborn, atropine and calcium are no longer recommended by the AAP or the AHA during the acute phase of neonatal resuscitation. These medications are used sometimes in special circumstances in resuscitation (such as atropine for severe reflex bradycardia after repeated attempts of suction or intubation resulting in a vagal response with prolonged bradycardia).

4. Other supportive measures

   1. Temperature regulation. Although some degree of cooling in a newborn infant is desirable because it provides a normal stimulus to respiratory effort, excessive cooling increases oxygen consumption and exacerbates acidosis. This is a problem especially for preterm infants, who have thin skin, decreased stores of body fat, and increased body surface area. Heat loss may be prevented by the following measures.

      1. Dry the infant thoroughly immediately after delivery.

      2. Maintain a warm delivery room.

      3. Place the infant under a prewarmed radiant warmer. (See Chapter 7.) Cover extremely preterm infants (<1500 g) with plastic wrap or a plastic bag up to the neck, and place a portable warming pad under the layers of towel on the resuscitation table.

   2. Preparation of the parents for resuscitation. Initial resuscitation usually occurs in the delivery room with one or both parents present. It is helpful to prepare the parents in advance, if possible. Describe what will be done, who will be present, who will explain what is happening, where the resuscitation will take place, where the father should stand, why crying may not be heard, and where the infant will be taken after stabilization. (See Chapter 50.)

   3. Withholding or discontinuing resuscitation. A consistent and coordinated approach by the obstetric and neonatal teams with prenatal involvement of parents is important in making decisions regarding potentially withholding resuscitation efforts. In situations where functional survival is highly unlikely, it is reasonable not to initiate resuscitation. Examples include extreme prematurity (<22 weeks or birthweight <400 g) or major chromosomal abnormalities, such as trisomy 13. Regional outcomes must be taken into account when making decisions regarding withholding resuscitation. When a newborn infant has no detectable heart rate, it is appropriate to consider stopping resuscitation efforts after 10 minutes.