Diagnostics in the delivery room

The pulse oximetry transducer (for SaO2 and HR monitoring) is secured with elastic tape by the second or third assistant, preferably on the neonate's right hand, after suctioning and drying (i.e., within first minute of life). Pulse oximetry is used for monitoring during neonatal resuscitation and transport (see pp. 131–2). SpO2 and blood pressure values obtained from the right arm and leg may provide information on right-to-left (ductal) shunting and outflow tract obstructions (e.g., coarctation of the aorta, interrupted aortic arch); the latter are rarely immediately evident in the delivery room since a large patent ductus arteriosus is common and may “bridge” outflow tract obstruction in these lesions. Capillary or venous blood gas analysis and blood glucose sticks (quick test with test strips) should be performed for all initially depressed neonates with metabolic acidosis (umbilical arterial pH <7.15), for preterm infants and for growth-restricted term infants. An arterial blood gas analysis is the gold standard for assessment of oxygenation and ventilation of the newborn. For the transport team (NETS), it is advisable to obtain and document these measurements (i.e., capillary or venous blood gas plus blood glucose), even in well-adapted neonates with a normal umbilical artery pH, approximately 30 min after birth or prior to transport (for legal reasons). If the newborn infant is depressed, blood gas sampling must be done earlier and should be repeated while the neonate's condition remains critical.

Breathing

Immediately after the initial postnatal chest excursions, the neonate should be able to breathe spontaneously during the next few seconds, and gradually turn rosy (beginning at the torso, then the extremities) and should maintain a heart rate >100 bpm.

Gasping, apnea and bradycardia (HR <100 bpm) are indications for initiating bag-and-mask ventilation/PPV (see below). Prolonged and severe hypoxia results in anaerobic glycolysis, hypoglycemia, lactic acidosis, peripheral vasoconstriction/shock, cardiac depression and subsequently cell death (CNS, myocardium, and other organs/tissues).

Heart rate

The heart rate (HR) is determined by quick palpation of the pulse at the base of the umbilical cord and/or cardiac auscultation. A HR >100 bpm and variation with breathing are normal.

If the HR is below 100 bpm in spite of 30 s of respiratory stimulation, apply (repeat) oropharyngeal suctioning quickly, then initiate mask-PPV and continue resuscitation according to the standard algorithm (Figure 2.38, p. 157).

Skin color

A well-adapted neonate has rosy mucous membranes without oxygen supplementation. Acrocyanosis (bluish extremities, rosy body) is usually normal for a neonate, but it may be a sign of low environmental temperature (peripheral vasoconstriction).

Signs of central cyanosis are seen on the face, torso and mucous membranes. Extreme pallor can indicate reduced cardiac output, severe anemia (in which case one does not see cyanosis), infection, hypovolemia, acidosis, and/or hypothermia.

Heart rate (HR)

Measurement of the HR (at the umbilical cord, by auscultation, by pulse oximetry or ECG) is the most objective indicator of: (1) the newborn's clinical condition, (2) the need for PPV (HR <100 bpm) or chest compressions (HR <60 bpm), and (3) a good response to one's resuscitation efforts (e.g., rise in HR after successful mask-PPV or endotracheal intubation plus PPV). The HR should correlate with the pulse palpated (brachial or femoral artery).

Pulse oximetry (SpO2, HR)

An analysis of six studies aimed at estimating the “normal SpO2 in newborn infants in the first minutes of life” revealed that in term and near-term infants a (pre- or postductal) SpO2 of 90% was reached at about 5 minutes of life. The SpO2 at 1 min of life ranged from 40% to 70%. SpO2 was generally lower in preterm infants and in those delivered by cesarean section. Postductal SpO2 (feet) was 7–10 percentage points lower than preductal SpO2 30.

Heart rate and SpO2 tracings are more easily picked up when the transducer is placed at the hands rather than the feet (perfusion more often impaired in the feet). If the neonate shows no early signs of dyspnea (nasal flaring, retractions at about 5–15 min postnatally) and no longer needs supplemental oxygen, then the baby should be wrapped up warmly and laid on the mother's chest (if necessary, monitored with a pulse oximeter). The 10-min Apgar score and a 30-min postnatal blood glucose and blood gas analysis can be obtained thereafter.

Rapid initial assessment (0–30 s after birth) and stimulation

After birth, assessment of breathing and heart rate is done rapidly (see p. 131, pp. 142–9, pp. 150–3), as follows:

• Palpate the umbilical cord or auscultate the heart: HR >100 bpm? Assistant may tap out HR for other resuscitators

• Is meconium visible? (Check in particular for staining of cord stump and nail beds)

• Suction (first mouth, then nose), if needed (see pp. 66–9)

• Dry and thereby stimulate breathing/keep warm (certain exceptions may apply)

• If still pale/cyanotic/insufficient breathing, proceed to stimulation (with four fingers while drying the back, may also rub the soles of the feet and sternum)

• O2 supplementation as needed if SpO2 <85%–90% (FiO2 0.21–1.0, flow 5 1/min)

If there are signs of severe neonatal compromise/terminal (aka: secondary) apnea present, perform PPV (see below)

Oxygen supplementation

Postnatally administered oxygen (via hood, mask, phargngeal-CPAP, intubation/PPV) is a very effective “drug” (oxygen decreases PVR, increases pulmonary blood flow and oxygenation, and induces ductus constriction).