INITIATION OF AIR BREATHING
CARE IN THE DELIVERY ROOM
EVALUATION OF NEWBORN CONDITION
ROUTINE NEWBORN CARE
The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists (2012) recommend attendance at delivery of at least one person whose primary responsibility is the neonate and who is capable of initiating resuscitation that includes intubation, vascular access, and medication administration. This usually is a pediatrician, nurse practitioner, anesthesiologist, nurse anesthetist, or specially trained nurse. However, in their absence, the responsibility for neonatal resuscitation falls to the obstetrical attendant. Thus, obstetricians should be well versed in measures for immediate care of the newborn.
INITIATION OF AIR BREATHING
Immediately following birth, the infant must promptly convert to air breathing as the fluid-filled alveoli expand with air and pulmonary perfusion is established. The newborn begins to breathe and cry almost immediately after birth, which indicates establishment of active respiration. Some factors that appear to influence the first breath include:
• Physical stimulation—examples include handling the neonate during delivery.
• Oxygen deprivation and carbon dioxide accumulation—these serve to increase the frequency and magnitude of breathing movements both before and after birth (Dawes, 1974).
• Thoracic compression—this occurs during pelvic descent, following which vaginal birth forces fluid from the respiratory tract in volume equivalent to approximately a fourth of the ultimate functional residual capacity (Saunders, 1978).
• Aeration of the newborn lung does not involve the inflation of a collapsed structure, but instead, the rapid replacement of bronchial and alveolar fluid by air. After delivery, the residual alveolar fluid is cleared through the pulmonary circulation and to a lesser degree, through the pulmonary lymphatics (Chernick, 1978). Delay in fluid removal from the alveoli probably contributes to the syndrome of transient tachypnea of the newborn (TTN) (Guglani, 2008). As fluid is replaced by air, compression of the pulmonary vasculature is reduced considerably, and in turn, resistance to blood flow is lowered. With the fall in pulmonary arterial blood pressure, the ductus arteriosus normally closes (Fig. 7-8, p. 136).
High negative intrathoracic pressures are required to bring about the initial entry of air into the fluid-filled alveoli. Normally, from the first breath after birth, progressively more residual air accumulates in the lung, and with each successive breath, lower pulmonary opening pressure is required. In the normal mature newborn, by approximately the fifth breath, pressure-volume changes achieved with each respiration are very similar to those of the adult. Thus, the breathing pattern shifts from the shallow episodic inspirations characteristic of the fetus to regular, deeper inhalations (Chap. 17, p. 337). Surfactant, which is synthesized by type II pneumocytes and already present in the alveoli, lowers alveolar surface tension and thereby prevents lung collapse. Insufficient surfactant, common in preterm infants, leads promptly to respiratory distress syndrome, which is described in Chapter 34 (p. 653).
CARE IN THE DELIVERY ROOM
Personnel designated for infant support are responsible for immediate care and for acute resuscitation initiation if needed.
Before and during delivery, careful consideration must be given to several determinants of neonatal well-being including: (1) maternal health status; (2) prenatal complications, including any suspected fetal malformations; (3) gestational age; (4) labor complications; (5) duration of labor and ruptured membranes; (6) type and duration of anesthesia; (7) difficulty with delivery; and (8) medications given during labor and their dosages, administration routes, and timing relative to delivery.
The International Liaison Committee on Resuscitation (ILCOR) updated its guidelines for neonatal resuscitation that are sanctioned by the American Academy of Pediatrics and the American Heart Association (Biban, 2011; Perlman, 2010). These substantially revised guidelines are incorporated into the following sections.
Approximately 10 percent of newborns require some degree of active resuscitation to stimulate breathing, and 1 percent require extensive resuscitation. It is perhaps not coincidental that there is a two- to threefold risk of death for newborns delivered at home compared with those delivered in hospitals (American College of Obstetricians and Gynecologists, 2013b). When deprived of oxygen, either before or after birth, neonates demonstrate a well-defined sequence of events leading to apnea (Fig. 32-1). With oxygen deprivation, there is a transient period of rapid breathing, and if it persists, breathing stops, which is termed primary apnea. This stage is accompanied by a fall in heart rate and loss of neuromuscular tone. Simple stimulation and exposure to oxygen will usually reverse primary apnea. If oxygen deprivation and asphyxia persist, however, the newborn will develop deep gasping respirations, followed by secondary apnea. This latter stage is associated with a further decline in heart rate, falling blood pressure, and loss of neuromuscular tone. Neonates in secondary apnea will not respond to stimulation and will not spontaneously resume respiratory efforts. Unless ventilation is assisted, death follows. Clinically, primary and secondary apneas are indistinguishable. Thus, secondary apnea must be assumed and resuscitation of the apneic newborn must be started immediately.
FIGURE 32-1 Physiological changes associated with primary and secondary apnea in the newborn. bpm = beats per minute; HR = heart rate; MAP = mean arterial pressure. (Adapted from Kattwinkel, 2006.)
The updated algorithm for newborn resuscitation recommended by ILCOR and the International Consensus on Cardiopulmonary Resuscitation is shown in Figure 32-2. Many of its tenets follow below.
FIGURE 32-2 Algorithm for resuscitation of the newborn. CPAP = continuous positive airway pressure; HR = heart rate; IV = intravenous. (Adapted from Perlman, 2010.)
The vigorous newborn is first placed in a warm environment to minimize heat loss, the airway is cleared, and the infant dried. Routine gastric aspiration has been shown to be nonbeneficial and even harmful (Kiremitci, 2011). And although previously recommended, there is no evidence that bulb suctioning for clear or meconium-stained fluid is beneficial, even if the newborn is depressed (Chap. 33, p. 638). With stimulation, the healthy newborn will take a breath within a few seconds of birth and cry within half a minute, after which routine supportive care is provided.
Assessment at 30 Seconds of Life. Apnea, gasping respirations, or heart rate < 100 bpm beyond 30 seconds after delivery should prompt administration of positive-pressure ventilation with room air (Fig. 32-3). Assisted ventilation rates of 30 to 60 breaths per minute are commonly employed, and the percent of oxygen saturation is monitored by pulse oximetry. At this point, supplemental oxygen can be given in graduated increasing percentages to maintain oxygen saturation (Spo2) values within a normal range (Vento, 2011). Adequate ventilation is indicated by improved heart rate.
FIGURE 32-3 Correct use of bag-and-mask ventilation. The head should be in a sniffing position with the tip of the nose pointing to the ceiling. The neck should not be hyperextended.
Assessment at 60 Seconds of Life. If the heart rate remains < 100 bpm, then ventilation is inadequate. The head position should be checked as shown in Figure 32-3, secretions cleared, and if necessary, inflation pressure increased. If the heart rate persists below 100 bpm beyond 60 seconds, tracheal intubation is considered. A number of conditions may be the cause of inadequate response, including the following:
• Hypoxemia or acidosis from any cause
• Drugs administered to the mother before delivery
• Upper airway obstruction
• Lung abnormalities
• Meconium aspiration
• Central nervous system developmental abnormality
• Sepsis syndrome.
If bag-and-mask ventilation is ineffective or prolonged, tracheal intubation is then performed. Other indications include the need for chest compressions or tracheal administration of medications, or special circumstances such as extremely low birthweight or a congenital diaphragmatic hernia. A laryngoscope with a straight blade—size 0 for a preterm infant and size 1 for a term neonate—is introduced at the side of the mouth and then directed posteriorly toward the oropharynx as shown in Figure 32-4. The laryngoscope is next moved gently into the vallecula—the space between the base of the tongue and the epiglottis. Gentle elevation of the laryngoscope tip will raise the epiglottis and expose the glottis and the vocal cords. The tube is then introduced through the vocal cords. Gentle cricoid pressure may be useful. Tube sizes vary from 3.5 to 4.0 mm for term infants down to 2.5 mm for those < 28 weeks or < 1000 g.
FIGURE 32-4 Sagittal view of laryngoscope positioning during intubation. The laryngoscope blade is inserted between the tongue base and epiglottis. Upward tilting of the tongue also lifts the epiglottis. The endotracheal tube is then threaded below the epiglottis and between the vocal cords (inset) to enter the trachea.
Several steps are taken to ensure that the tube is positioned in the trachea and not the esophagus: observation for symmetrical chest wall motion; auscultation for equal breath sounds, especially in the axillae; and auscultation for the absence of breath sounds or gurgling over the stomach. Tracheal suctioning is no longer recommended or discouraged. Using an appropriate ventilation bag attached to the tracheal tube, puffs of air are delivered into the tube at 1- to 2-second intervals with a force adequate to gently lift the chest wall. In term infants, pressures of 30 to 40 cm H2O typically will expand the alveoli without causing barotrauma. For preterm infants, pressures are 20 to 25 cm H2O. An increase in heart rate and Spo2 levels within acceptable ranges reflect a positive response.
If the heart rate remains < 60 bpm despite adequate ventilation for 30 seconds, chest compressions are initiated. These are delivered on the lower third of the sternum at a depth sufficient to generate a palpable pulse. A 3:1 compressions-to-ventilation ratio is recommended, with 90 compressions and 30 breaths to achieve approximately 120 events each minute. The heart rate is reassessed every 30 seconds, and chest compressions are continued until the spontaneous heart rate is at least 60 bpm.
Epinephrine and Volume Expansion
Intravenously administered epinephrine is indicated when the heart rate remains < 60 bpm after adequate ventilation and chest compressions. Epinephrine may be given through the endotracheal tube if venous access has not been estabished. The recommended intravenous dose is 0.01 to 0.03 mg/kg. If given through the tracheal tube, higher doses are employed—0.05 to 0.1 mg/kg.
For infants with blood loss, early volume replacement with crystalloid or packed red cells is indicated if they do not respond to resuscitation.
Discontinuation of Resuscitation
As expected, newborns with cardiopulmonary arrest who do not respond promptly to resuscitation are at great risk for death, and if they survive, for severe morbidity (Haddad, 2000). The International Consensus Committee concluded that discontinuation of resuscitative efforts may be appropriate in a neonate without a heartbeat for 10 minutes of continuous and adequate resuscitative efforts (Perlman, 2010). This committee cites lack of data for more specific recommendations regarding the infant whose heart rate remains < 60 bpm.
EVALUATION OF NEWBORN CONDITION
The scoring system described in 1953 by Dr. Virginia Apgar remains a useful clinical tool to identify those neonates who require resuscitation and to assess the effectiveness of any resuscitative measures. As shown in Table 32-1, each of the five easily identifiable characteristics—heart rate, respiratory effort, muscle tone, reflex irritability, and color—is assessed and assigned a value of 0 to 2. The total score, based on the sum of the five components, is determined in all neonates at 1 and 5 minutes after delivery. In depressed infants, the score may be calculated at further 5-minute intervals until a 20-minute Apgar score is assessed.
TABLE 32-1. Apgar Scoring System
The 1-minute Apgar score reflects the need for immediate resuscitation. The 5-minute score, and particularly the change in score between 1 and 5 minutes, is a useful index of the effectiveness of resuscitative efforts. The 5-minute Apgar score also has prognostic significance for neonatal survival because survival is related closely to the condition of the neonate in the delivery room (Apgar, 1958). In an analysis of more than 150,000 infants delivered at Parkland Hospital, Casey and associates (2001b) assessed the significance of the 5-minute score for predicting survival during the first 28 days of life. They found that in term neonates, the risk of neonatal death was approximately 1 in 5000 for those with Apgar scores of 7 to 10. This risk compares with a mortality rate of 1 in 4 for term infants with 5-minute scores of 3 or less. Low 5-minute scores were comparably predictive of neonatal death in preterm infants. These investigators concluded that the Apgar scoring system is as relevant for the prediction of neonatal survival today as it was more than 50 years ago.
There have been attempts to use Apgar scores to define asphyxial injury and to predict subsequent neurological outcome—uses for which the Apgar score was never intended. Such associations are difficult to measure with reliability given that both asphyxial injury and low Apgar scores are infrequent outcomes. For example, according to United States birth certificate records for 2010, only 1.8 percent of newborns had a 5-minute score below 7 (Martin, 2012). Similarly, in a population-based study of more than 1 million term infants born in Sweden between 1988 and 1997, the incidence of 5-minute Apgar scores of 3 or less was approximately 2 per 1000 (Thorngren-Jerneck, 2001).
Despite the methodological challenges, erroneous definitions of asphyxia by many groups were established based solely on low Apgar scores. These prompted the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics (2010) to issue a series of joint opinions with important caveats regarding limitations of use of the Apgar score. One is that because certain elements of the Apgar score are partially dependent on the physiological maturity of the newborn, a healthy preterm infant may receive a low score only because of immaturity (Catlin, 1986). Apgar scores may be influenced by a variety of factors including, but not limited to, fetal malformations, maternal medications, and infection. Therefore, it is inappropriate to use an Apgar score alone to diagnose asphyxia. A 5-minute Apgar score of 3 correlates poorly with adverse future neurological outcomes, and thus scores are measured also at 10, 15, and 20 minutes when the score remains 3 or less (Freeman, 1988; Nelson, 1981).
Importantly, the Apgar score alone cannot establish hypoxia as the cause of cerebral palsy. As discussed in Chapter 33 (p. 638), a neonate who has had an asphyxial insult proximate to delivery that is severe enough to result in acute neurological injury will demonstrate most of the following: (1) profound acidemia with cord artery blood pH < 7 and acid-base deficit ≥ 12 mmol/L; (2) Apgar score of 0–3 persisting for 10 minutes or longer; (3) neurological manifestations such as seizures, coma, or hypotonia; and (4) multisystem organ dysfunction—cardiovascular, gastrointestinal, hematological, pulmonary, or renal (American College of Obstetricians and Gynecologists and the American Academy of Pediatrics, 2003).
Umbilical Cord blood Acid–Base Studies
Blood taken from umbilical vessels may be used for acid-base studies to assess the metabolic status of the neonate. Blood collection is performed following delivery by immediately isolating a 10- to 20-cm segment of cord with two clamps placed near the neonate and another two clamps nearer the placenta. The importance of clamping the cord is underscored by the fact that delays of 20 to 30 seconds can alter both the Pco2 and pH (Valero, 2012; White, 2012). The cord is then cut between the two proximal clamps and then the two distal clamps.
Arterial blood is drawn from the isolated cord segment into a 1- to 2-mL commercially prepared plastic syringe containing lyophilized heparin or a similar syringe that has been flushed with a heparin solution containing 1000 U/mL. Once sampling is completed, the needle is capped and the syringe transported, on ice, to the laboratory. Although efforts should be made for prompt transport, neither the pH nor Pco2values change significantly in blood kept at room temperature for up to 60 minutes (Duerbeck, 1992). Mathematical models have been developed that allow reasonable prediction of birth acid–base status in properly collected cord blood samples analyzed as late as 60 hours after delivery (Chauhan, 1994). Also, Swedish investigators reported significant variances in acid-base measurements with the use of different analyzers (Mokarami, 2012).
Fetal Acid-Base Physiology
The fetus produces both carbonic and organic acids. Carbonic acid (H2CO3) is formed by oxidative metabolism of CO2. The fetus usually rapidly clears CO2 through the placental circulation. If CO2 clearance is lowered, then carbonic acid levels rise. When H2CO3 accumulates in fetal blood and there is no concurrent increase in organic acids, the result is termed respiratory acidemia. This often follows impaired placental exchange.
In contrast, organic acids primarily include lactic and β-hydroxybutyric acids. Levels of these increase with persistent placental exchange impairment and result from anaerobic glycolysis. These organic acids are cleared slowly from fetal blood, and when they accumulate without a concurrent increase in H2CO3, the result is termed metabolic acidemia. With the development of metabolic acidemia, bicarbonate (HCO3−) decreases because it is used to buffer the organic acid. An increase in H2CO3 accompanied by an increase in organic acid reflected by decreased HCO3− causes mixed respiratory-metabolic acidemia.
In the fetus, respiratory and metabolic acidemia and ultimately tissue acidosis are most likely part of a progressively worsening continuum. This is different from the adult pathophysiology, in which distinct conditions result in either respiratory acidosis—for example, pulmonary disease, or metabolic acidosis—for example, diabetes. In the fetus, the placenta serves as both the lungs and to a certain degree, the kidneys. One principal cause of fetal acidemia is a decrease in uteroplacental perfusion. This results in the retention of CO2, that is, respiratory acidemia, and if protracted and severe enough, a mixed or metabolic acidemia.
Assuming that maternal pH and blood gases are normal, the actual pH of fetal blood is dependent on the proportion of carbonic and organic acids and the amount of bicarbonate, which is the major buffer in blood. This can best be illustrated by the Henderson–Hasselbalch equation:
For clinical purposes, HCO3− represents the metabolic component and is reported in mEq/L. The H2CO3 concentration represents the respiratory component and is reported as the Pco2 in mm Hg. Thus:
The result of this equation is a pH value. Because pH is a logarithmic term, it does not give a linear measure of acid accumulation. For example, a change in hydrogen ion concentration associated with a fall in pH from 7.0 to 6.9 is almost twice that which is associated with a fall in pH from 7.3 to 7.2. For this reason, the change in base, termed delta base, offers a more linear measure of the degree of accumulation of metabolic acid (Armstrong, 2007). The delta base is a calculated number used as a measure of the change in buffering capacity of bicarbonate (HCO3−). The formula for calculating the base excess (BE) is as follows:
BE = 0.02786 × Pco2 × 10(pH – 6.1) × 13.77 × pH – 124.58
Shown in Figure 32-5 is a nomogram developed from which these can be calculated if only two parameters are known. For example, HCO3− concentration will be decreased with a metabolic acidemia as it is consumed to maintain a normal pH. A base deficit occurs when HCO3− concentration decreases to below normal levels, and a base excess occurs when HCO3− values are above normal. Importantly, a mixed respiratory–metabolic acidemia with a large base deficit and a low HCO3−, for example 12 mmol/L, is more often associated with a depressed neonate than is a mixed acidemia with a minimal base deficit and a more nearly normal HCO3− level.
FIGURE 32-5 Nomogram for determining the delta base. (Adapted from Siggaard-Andersen, 1963).
Clinical Significance of Acidemia
Fetal oxygenation and pH generally decline during the course of normal labor. Normal umbilical cord blood pH and blood gas values at delivery in term newborns are summarized in Table 32-2. Similar values have been reported for preterm infants (Dickinson, 1992; Ramin, 1989; Riley, 1993). The lower limits of normal pH in the newborn have been found to range from 7.04 to 7.10 (Boylan, 1994). Thus, these values should be considered to define neonatal acidemia. Even so, most fetuses will tolerate intrapartum acidemia with a pH as low as 7.00 without incurring neurological impairment (Freeman, 1988; Gilstrap, 1989). However, in a study of newborns with a pH < 7.0 from Parkland Hospital, there were inordinate proportions of neonatal deaths—8 percent, intensive-care admission—39 percent, intubations—14 percent, and seizures—13 percent (Goldaber, 1991). And in a study from Oxford of more than 51,000 term infants, the incidence of neonatal encephalopathy with the pH < 7.0 was 3 percent (Yeh, 2012).
TABLE 32-2. Umbilical Cord blood pH and blood Gas Values in Normal Term Newborns
Another important prognostic consideration is the direction of pH change from birth to the immediate neonatal period. For example, the risk of seizures during the first 24 hours of life was reduced fivefold if an umbilical artery cord pH below 7.2 normalized within 2 hours after delivery (Casey, 2001a).
Acute interruption in placental gas exchange is accompanied by subsequent CO2 retention and respiratory acidemia. The most common antecedent factor is transient umbilical cord compression. Generally, respiratory acidemia is not harmful to the fetus (Low, 1994).
The degree to which pH is affected by Pco2—the respiratory component of the acidosis—can be calculated. First, the upper normal neonatal Pco2 of 49 mm Hg is subtracted from the cord blood gas Pco2 value. Each additional 10 mm Hg Pco2 increment will lower the pH by 0.08 units (Eisenberg, 1987). Thus, in a mixed respiratory–metabolic acidemia, the benign respiratory component can be calculated. As an example, acute cord prolapse during labor prompts cesarean delivery of an infant 20 minutes later. The umbilical artery blood gas pH was 6.95 and the Pco2 was 89 mm Hg. To calculate the degree to which the cord compression and subsequent impairment of CO2 exchange affected the pH, the relationship given earlier is applied: 89 mm Hg minus 49 mm Hg = 40 mm Hg excess CO2. To correct pH: (40 ÷ 10) × 0.08 = 0.32; 6.95 + 0.32 = 7.27. Therefore, the pH before cord prolapse was approximately 7.27, well within normal limits, and thus the low pH resulted from respiratory acidosis.
The fetus begins to develop metabolic acidemia when oxygen deprivation is of sufficient duration and magnitude to require anaerobic metabolism for cellular energy needs. Low and associates (1997) defined fetal acidosis as a base deficit ≥ 12 mmol/L and severe fetal acidosis as a base deficit ≥ 16 mmol/L. In the Parkland study of more than 150,000 newborns cited earlier, metabolic acidemia was defined using umbilical cord blood gas cutoffs that were 2 standard deviations below the mean (Casey, 2001b). Thus, metabolic acidemia was an umbilical artery blood pH < 7.00 accompanied by a Pco2 of ≤ 76.3 mm Hg, with higher values indicating a respiratory component; HCO3−concentration ≤ 17.7 mmol/L; and base deficit ≥ 10.3 mEq/L. From the standpoint of possible cerebral palsy causation, the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics (2003), in their widely endorsed monograph, defined metabolic acidosis as umbilical arterial pH < 7.0 and a base deficit ≥ 12 mmol/L.
Metabolic acidemia is associated with a high rate of multiorgan dysfunction. In rare cases, such hypoxia-induced metabolic acidemia may be so severe that it causes subsequent neurological impairment—hypoxic-ischemic encephalopathy (Chap. 33, p. 639). In fact, a fetus without such acidemia cannot by definition have suffered recent hypoxic-induced injury. That said, severe metabolic acidosis is poorly predictive of subsequent neurological impairment in the term neonate. Although metabolic acidosis was associated with an increase in immediate neonatal complications in a group of infants with depressed 5-minute Apgar scores, there were no differences in umbilical artery blood gas measurements among infants who subsequently developed cerebral palsy compared with those with normal neurological outcomes (Socol, 1994).
In very-low-birthweight infants, that is, those < 1000 g, newborn acid-base status may be more closely linked to long-term neurological outcome (Gaudier, 1994; Low, 1995). In the study cited above, Casey and coworkers (2001b) described the association between metabolic acidemia, low Apgar scores, and neonatal death in term and preterm infants. Regarding term neonates, as shown in Figure 32-6, relative to newborns with a 5-minute Apgar score of at least 7, the risk of neonatal death was more than 3200-fold greater in term infants with metabolic acidemia and 5-minute scores of 3 or less.
FIGURE 32-6 Relative risk for neonatal death in term infants with low Apgar score or umbilical artery acidemia—or both. The relative risk is cited above each bar. (Data from Casey, 2001b.)
Recommendations for Cord blood Gas Determinations
A cost-effectiveness analysis for universal cord blood gas measurements has not been conducted. In some centers, such as ours at Parkland Hospital, cord gas analysis is performed in all neonates at birth. The American College of Obstetricians and Gynecologists (2012) recommends that cord blood gas and pH analyses be obtained in the following circumstances:
• Cesarean delivery for fetal compromise
• Low 5-minute Apgar score
• Severe fetal-growth restriction
• Abnormal fetal heart rate tracing
• Maternal thyroid disease
• Intrapartum fever
• Multifetal gestation.
Although umbilical cord acid-base blood determinations are poorly predictive of either immediate or long-term adverse neurological outcome, they provide the most objective evidence of the fetal metabolic status at birth.
Eye Infection Prophylaxis
Ophthalmia neonatorum is mucopurulent conjunctivitis of newborns. Some form of conjunctivitis affects 1 to 12 percent of all neonates, and gonococcal and chlamydial infections are some of the most common causes (Zuppa, 2011). blindness was previously common in children who developed Neisseria gonorrhoeae infection. However, in 1884, Credé, a German obstetrician, introduced a 1-percent ophthalmic solution of silver nitrate that largely eliminated this. Various other antimicrobial agents have also proven to be effective, and gonococcal prophylaxis is now mandatory for all neonates (American Academy of Pediatrics and American College of Obstetricians and Gynecologists, 2012). Recommendations for gonococcal eye prophylaxis include a single application of either 1-percent silver nitrate solution or 0.5-percent erythromycin or 1-percent tetracycline ophthalmic ointment soon after delivery. Treatment of presumptive gonococcal ophthalmia, that is, conjunctivitis in a neonate born to a mother with untreated gonorrhea, is given with single-dose ceftriaxone, 100 mg/kg, either intramuscularly or intravenously. Testing for both gonococcus and chlamydia should be obtained before treatment.
Adequate neonatal prophylaxis against chlamydial conjunctivitis is complex. Ideally, prenatal screening and treatment for Chlamydia trachomatis obviates conjunctival infection (Hammerschlag, 2011). Of neonates delivered vaginally of mothers with an active chlamydial infection, from 12 to 25 percent will develop conjunctivitis for up to 20 weeks (Teoh, 2003). Prophylactic topical eye treatments do not reliably reduce the incidence of chlamydial conjunctivitis. In a study from Kenya, 2.5-percent povidone-iodine solution was reported to be superior to either 1-percent silver nitrate solution or 0.5-percent erythromycin ointment in preventing chlamydial conjunctivitis (Isenberg, 1995). In another study from Iran, povidone-iodine eye drops were twice as effective in preventing clinical conjunctivitis as erythromycin drops—9 versus 18 percent failure rate, respectively (Ali, 2007). In an Israeli study, tetracycline ointment was marginally superior to povidone-iodine (David, 2011). For all of these reasons, conjunctivitis in a newborn up to 3 months old should prompt consideration for chlamydial infection. Treatment for chlamydial infection is with oral azithromycin for 5 days or erythromycin for 14 days.
Hepatitis B Immunization
Routine immunization of all newborns with thimerosal-free vaccine against hepatitis B before hospital discharge is standard practice (American Academy of Pediatrics and American College of Obstetricians and Gynecologists, 2012). This vaccine does not appear to increase the number of febrile episodes, sepsis evaluations, or adverse neurological sequelae (Lewis, 2001). Some advocate treatment of high-risk or even all seropositive women with antiviral nucleoside or nucleotide analogues during pregnancy to minimize transmission to the fetus (Dusheiko, 2012; Tran, 2012). Certainly, if the mother is seropositive for hepatitis B surface antigen, then the neonate should also be passively immunized with hepatitis B immune globulin as discussed in Chapter 55 (p. 1090).
This injection is provided to prevent vitamin K-dependent hemorrhagic disease of the newborn, which is discussed in Chapter 33 (p. 644). A single dose of 0.5- to 1-mg intramuscular vitamin K is given within 1 hour of birth (American Academy of Pediatrics and American College of Obstetricians and Gynecologists, 2012).
State-based public-health newborn screening programs were solidified when, in response to calls for a uniform national policy, the Maternal and Child Health Bureau appointed a committee of the American College of Medical Genetics to recommend a panel of tests (Watson, 2006). Technical advances have made a large number of relatively simply performed mass screening tests available for newborn conditions, and many are mandated by various state laws (American College of Obstetricians and Gynecologists, 2011b). Since then, two have been added to the original core panel of 29 congenital conditions, and all are shown in Table 32-3.
TABLE 32-3. Newborn Screening Core Panel—Estimated Number of Children Shown in Parentheses Identified in the United States in 2006
According to the Centers for Disease Control and Prevention (2012b), the programs have been successful and cost effective. For example, neonatal screening for hearing loss was shown in a Dutch study to diagnose problems a mean of 6 months earlier and improve long-term outcomes (Durieux-Smith, 2008). A successful screening program for medium chain acyl-CoA dehydrogenase deficiency was described in a Danish study (Anderson, 2012). The use of pulse oximetry to screen for severe congenital heart disease was reviewed by Thangaratinam (2012).
Most states require that all tests in the core panel be performed. Supplemental conditions—secondary targets—are also listed on the Maternal and Child Health Bureau website. Some states require some of these 24 in addition to their mandated core panel. Each practitioner should be familiar with their individual state requirements, which are available at http://genes-r-us.uthscsa.edu/resources/consumer/statemap.htm and http://www.hrsa.gov/advisorycommittee/mchbadvisory/heritabledisorders/recommendedpanel/index/html.
ROUTINE NEWBORN CARE
Gestational Age Estimation
Newborn gestational age can be estimated very soon after delivery. The relationship between gestational age and birthweight should be used to identify neonates at risk for complications (McIntire, 1999). For example, neonates who are either small or large for gestational age are at increased risk for hypoglycemia and polycythemia, and measurements of blood glucose and hematocrit are indicated (American Academy of Pediatrics and American College of Obstetricians and Gynecologists, 2012).
Care of Skin and Umbilical Cord
All excess vernix, bull-listood, and meconium should be gently wiped off at the time of delivery while keeping the infant warm. Any remaining vernix is readily absorbed and disappears within 24 hours. The first bath should be postponed until the neonate’s temperature has stabilized.
Aseptic precautions should be observed in the immediate care of the cord. The American Academy of Pediatrics and the American College of Obstetrics and Gynecologists (2012) have concluded that keeping the cord dry is sufficient care. The umbilical cord begins to lose water from Wharton jelly shortly after birth. Within 24 hours, the cord stump loses its characteristic bull-listuish-white, moist appearance and soon becomes dry and black. Within several days to weeks, the stump sloughs and leaves a small, granulating wound, which after healing forms the umbilicus. Separation usually takes place within the first 2 weeks, with a range of 3 to 45 days (Novack, 1988). The umbilical cord dries more quickly and separates more readily when exposed to air. Thus, a dressing is not recommended.
In resource-poor countries, prophylaxis is reasonable. Triple-dye applied to the cord was reported superior to soap and water care in preventing colonization and exudate formation (Janssen, 2003). In a Nepalese study, cleansing the cord stump with 4-percent chlorhexidine reduced severe omphalitis by 75 percent compared with soap and water cleansing (Mullany, 2006). Likewise, 0.1-percent chlorhexidine powder was superior to dry cord care (Kapellen, 2009).
Despite precautions, a serious umbilical infection—omphalitis—is sometimes encountered. In a German study of more than 750 newborns with aseptic cord care, 1.3 percent developed omphalitis (Kapellen, 2009). The most likely offending organisms are Staphylococcus aureus, Escherichia coli, and group B streptococcus. Typical signs of cellulitis and stump discharge usually aid diagnosis. However, mild erythema and some bleeding at the stump site with cord detachment is common, and some cases may present no outward signs. Thus, the diagnosis can be elusive.
Feeding and Weight Loss
According to the American College of Obstetricians and Gynecologists (2013a), exclusive breast feeding is preferred until 6 months. In many hospitals, infants begin breast feeding in the delivery room. Most term newborns thrive best when fed 8 to 12 times daily for approximately 15 minutes per episode. Preterm or growth-restricted newborns require feedings at shorter intervals.
One goal of Healthy People 2020 of the United States Department of Health and Human Services (2010) is to increase the proportion of mothers who breast feed their infants. Substantial progress toward this goal has been made. In 2009, 77 percent of infants were initially breast fed, and 47 percent were still breast fed at 6 months and 26 percent at 1 year (Centers for Disease Control and Prevention, 2012a). Breast feeding is discussed further in Chapter 36(p. 673). Because most neonates actually receive little nutriment for the first 3 or 4 days of life, they progressively lose weight until the flow of maternal milk has been established or other feeding is instituted. Preterm infants lose relatively more weight and regain their birthweight more slowly. Conversely, growth-restricted but otherwise healthy infants regain their initial weight more quickly than those born preterm. With proper nourishment, birthweight of term infants usually is regained by the end of the 10th day.
Stools and Urine
For the first 2 or 3 days after birth, the colon contains soft, brownish-green meconium. This consists of desquamated epithelial cells from the intestinal tract, mucus, epidermal cells, and lanugo (fetal hair) that have been swallowed along with amnionic fluid. The characteristic color results from bile pigments. During fetal life and for a few hours after birth, the intestinal contents are sterile, but bacteria quickly colonize the bowel.
Meconium stooling is seen in 90 percent of newborns within the first 24 hours, and most of the rest within 36 hours. Usually, newborns first void shortly after birth, but may not until the second day. Meconium and urine passage indicates patency of the gastrointestinal and urinary tracts, respectively. Failure of the newborn to stool or urinate after these times suggests a congenital defect, such as imperforate anus or a urethral valve. After the third or fourth day, as a result of milk ingestion, meconium is replaced by light-yellow homogenous feces with a consistency similar to peanut butter.
Between the second and fifth day of life approximately one third of all neonates develop so-called physiological jaundice of the newborn. It has special significance considering most hospitals have policies for early discharge. Correspondingly, it has been the subject of several recent reviews and is discussed further in Chapter 33 (p. 644) (Dijk, 2012; Gazzin, 2011; Hansen, 2011; Lauer, 2011).
Newborn Male Circumcision
Neonatal circumcision has been a controversial topic in the United States for at least 25 years. For centuries, newborn male circumcision has been performed as a religious ritual. Even so, scientific evidence supports several medical benefits that include prevention of phimosis, paraphimosis, and balanoposthitis. Circumcision also decreases the incidence of penile cancer and of cervical cancer among their sexual partners. In 1999, the American Academy of Pediatrics concluded that existing evidence was insufficient to recommend routine neonatal circumcision. It seems that this policy has had only a negligible effect on practices in this country. Specifically, the Centers for Disease Control and Prevention (2011) estimated that the newborn male circumcision rate decreased during a 12-year period from approximately 60 percent in 2009 to only 55 percent in 2010.
Subsequent studies have again endorsed health benefits of circumcision. In two large randomized trials from regions of Africa with a high prevalence of human immunodeficiency virus (HIV), adult male circumcision was found to lower the risk of HIV acquisition by half (Bailey, 2007; Gray, 2007). And adult male circumcision was reported to decrease incidences of HIV, HPV, and herpes infections (Tobian, 2009). These and other studies were considered by the American Academy of Pediatrics Task Force on Circumcision (2012). In its policy statement, the Task Force concluded that health benefits of newborn male circumcision outweigh the risks, and thus, access to the procedure is justified for families who choose it. Benefits cited include prevention of urinary infections, penile cancer, and transmission of some sexually transmitted infections, including HIV infection. The Task Force stopped short of recommending circumcision for all newborns. The American College of Obstetricians and Gynecologists (2011a) endorses these views.
Anesthesia for Circumcision
The American Academy of Pediatrics Task Force (2012) recommends that if circumcision is performed, procedural analgesia should be provided. Various pain relief techniques have been described, including lidocaine-prilocaine topical cream, local analgesia infiltration, dorsal penile nerve block, or ring block. Several studies attest to the efficacy of the dorsal penile nerve block (Arnett, 1990; Stang, 1988). Studies show that the dorsal penile nerve block or the ring block techniques are both superior to topical analgesia (Hardwick-Smith, 1998; Lander, 1997; Taddio, 1997). The use of a pacifier dipped in sucrose is a useful adjunct to these methods (Kaufman, 2002).
After appropriate penile cleansing, the ring block technique consists of placing a wheal of 1-percent lidocaine at the base of the penis and advancing the needle in a 180-degree arc around the base of the penis first to one side and then the other to achieve a circumferential ring of analgesia. The maximum dose of lidocaine is 1.0 mL. No vasoactive compounds such as epinephrine should ever be added to the local analgesic agent.
Newborn circumcision should be performed only on a healthy neonate. Other contraindications include any genital abnormalities such as hypospadias and a family history of a bleeding disorder unless excluded in the infant. The most commonly used instruments are shown in Figure 32-7 and include Gomco and Mogen clamps and the Plastibell device. Compared with the Gomco procedure, Kaufman and colleagues (2002) reported that the Mogen technique required less time to perform and was associated with less apparent discomfort for the newborn. Regardless of the method used, the goal is to remove enough shaft skin and inner preputial epithelium so that the glans is exposed sufficiently to prevent phimosis. In all techniques: (1) the amount of external skin to be removed must be accurately estimated, (2) the preputial orifice must be dilated to visualize the glans and ensure that it is normal, (3) the inner preputial epithelium must be freed from the glans epithelium, and (4) the circumcision device must be left in place long enough to produce hemostasis before amputating the prepuce (Lerman, 2001). For a detailed description of surgical techniques, see the second edition of Operative Obstetrics (Mastrobattista, 2002).
FIGURE 32-7 Three different tools used for circumcision. A. Mogen clamp. The arms of the clamp open to a 3-mm maximum width. B. Gomco clamp, assembled. C. Plastibell device.
As with any surgical procedure, there is a risk of bleeding, infection, and hematoma formation. These risks, however, are low (Christakis, 2000). Unusual complications reported as isolated cases include distal glans amputation, acquisition of human immunodeficiency virus-1 (HIV-1) infection or other sexually transmitted diseases, meatal stenosis, penile denudation, penile destruction with electrosurgical coagulation, subsequent epidermal inclusion cyst and urethrocutaneous fistula, and ischemia following the inappropriate use of lidocaine with epinephrine (Amukele, 2003; Berens, 1990; Gearhart, 1989; Neulander, 1996; Nicoll, 1997; Pippi-Salle, 2013; Upadhyay, 1998).
This model of maternity care place newborns in their mothers’ rooms instead of central nurseries. Termed rooming-in, this approach first appeared in United States hospitals in the early 1940s (Temkin, 2002). In part, rooming-in stems from a trend to make all phases of childbearing as natural as possible and to foster early mother-child relationships. By 24 hours, the mother is generally fully ambulatory. Thereafter, with rooming-in, she can usually provide routine care for herself and her newborn. An obvious advantage is her increased ability to assume full care of the infant when she arrives home.
Traditionally, the newborn is discharged with its mother, and in most cases, maternal stay has determined that of the neonate. Safe discharge for late preterm infants has special concerns (Whyte, 2012). From 1970 to the mid-1990s, average maternal postpartum length of stay declined steadily, and many mothers were discharged in under 48 hours. Although it is clear that most newborns can be safely discharged within 48 hours, this is not uniformly true. For example, using data from the Canadian Institute for Health Information, Liu and colleagues (2000) examined readmission rates in more than 2.1 million neonatal discharges. As the length of hospital stay decreased from 4.2 days in 1990 to 2.7 days in 1997, the readmission rate increased from 27 to 38 per 1000 births. Dehydration and jaundice accounted for most of these readmissions, and brain damage from icterus neonatorum is discussed in Chapter 33 (p. 644). Using Washington state neonatal discharge data, Malkin and coworkers (2000) found that the 28-day mortality rate was increased fourfold and the 1-year mortality rate increased twofold in newborns discharged within 30 hours of birth.
Because of the increased scrutiny regarding short hospital stays, federal legislation—The Newborns’ and Mothers’ Health Protection Act of 1996—was enacted to prohibit insurers from restricting hospital stays for mothers and newborns to less than 2 days for vaginal delivery or 4 days for cesarean delivery. As a result, the average length of hospital stay for childbirth increased from 2.1 days in 1995 to 2.5 days in 2000. This increase reflected the reduced number of very short hospital stays following childbirth (Hall, 2002). Although Mosen and associates (2002) found that implementation of the new legislation was associated with a 6-percent increase in cost, readmission rates within 7 days of discharge decreased by nearly half. In an analysis of more than 662,000 births in California, Datar and Sood (2006) found decreased rates of readmission of 9, 12, and 20 percent, respectively, at 1, 2, and 3 years after the legislation was implemented.
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