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Positioning of the Newborn
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After delivery, the infant should be dried with warm towels and placed supine under a radiant warmer. The head should be put into a “sniffing” position which aligns the posterior pharynx, larynx, and trachea and allows for unimpeded air entry (Fig. 21-2). Oral and nasal suctioning should be performed with a bulb syringe or suction catheter, turning the infants head to the side if copious secretions are present. The mouth should be suctioned prior to suctioning the nose so that the oropharynx is clear of secretions if the infant suddenly gasps during nasal suctioning. One way to remember to suction the mouth before nose is that “M” comes before “N” in the alphabet.2 When suctioning the mouth and posterior oropharynx, it is important not to suction too vigorously or deeply, which is shown in some circumstances to cause bradycardia and apnea.2
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Newborns are at risk for hypothermia following delivery because of their large surface area to body-mass ratio as well as evaporative heat loss. Hypothermia can lead to hypoglycemia, increased oxygen consumption and if severe, respiratory depression, and acidosis. This can be avoided by careful drying of the infant with warm towels and placing the infant under a radiant heat source. Very low-birth-weight infants (<1500 g) are particularly prone to hypothermia and may need to be placed under plastic wrapping to avoid evaporative loss.1 Continual monitoring of temperature is very important, because hyperthermia can have deleterious effects such as worsening ischemic brain injury.
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For vigorous newborns, drying and suctioning of the mouth is usually adequate stimulation as evidenced by increased heart rate and respiratory effort. If the infant does not have adequate respirations, rubbing the infant's trunk and flicking the soles of the feet should be initiated.1 If the newborn does not respond promptly to tactile stimulation, positive-pressure ventilation (PPV) should be initiated. It is important not to mistake gasping for breathing. Gasping is a series of deep, irregular or rapid respirations that are indicative of respiratory depression or hypoxia and require the same intervention that no observed respiratory effort would require.2
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If the infant is not breathing adequately or has a heart rate less than 100 beats/min (best evaluated by palpating the base of the umbilical cord), PPV should be initiated immediately. Administering free-flow oxygen or continuing tactile stimulation for a baby that is not breathing is not valuable and only delays appropriate treatment.2 The baby's skin color, observing the lips, mouth, and torso, should be assessed, because the transition from cyanosis to pink color is an rapid indicator of oxygenation. Acrocyanosis, which is cyanosis of the hands and feet, represents peripheral vasoconstriction and is not an indication for administering oxygen. Central cyanosis may be an indicator for further intervention, but this is complicated by several factors. Skin color is often an unreliable indicator of oxygen saturation (Spo2) and may be difficult to interpret due to skin pigmentation. Also, studies have shown that normal term infants take several minutes to transition from the intrauterine 60% oxygen saturation to the normal room air oxygen saturation of 90%.4 Because of this, updated AHA guidelines recommend preductal oxygen saturation (attaching oximeter probe to the right hand) to be utilized if central cyanosis is persistent.1 Obtaining a reliable oximeter signal may take several minutes and should not delay the resuscitation effort. Once a good oximeter signal is obtained, an oxygen/air blender (Fig. 21-3) should be utilized to titrate the administered oxygen between 21% and 100% to achieve target values at different times after birth (Table 21-4). For term infants, 21% oxygen should be used initially and the oxygen percentage should be increased as needed based on pulse oximeter. There is evidence that preterm infants should be started on a higher percentage of oxygen during resuscitation.5,6 Administration of 100% oxygen is not recommended, especially in preterm infants, due to deleterious effects.2 Oxygen can be weaned and then discontinued when there is no central cyanosis, oximetry saturations are above 90%, and there is no respiratory distress. If this is not the case, a trial of PPV should be initiated.
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The normal newborn breathes or cries spontaneously within seconds of birth and establishes regular respirations within the first minute of life. PPV is indicated if the infant remains apneic or gasping, the heart rate is <100 beats/min after 30 seconds of initial resuscitation, or has central cyanosis despite supplemental oxygen. Ventilation of the lungs is the single most important aspect of resuscitation of the compromised newborn.2 Ventilation is performed using a cushioned mask with either a self- or flow-inflating bag or a T-piece resuscitator (Fig. 21-4). Breaths are delivered when the operator occludes and opens the aperture on the device connected to the mask. The mask must make a tight seal over the nose and mouth and the pop-off valve may need to be bypassed because of the high peak inspiratory pressures needed for the initial breaths. Peak pressures up to 40 cm H2O may be necessary because of the “stiff” fluid-filled lungs of newborns. After the initial breaths, the fluid will begin to be expressed from the lungs and lower pressures can be utilized. It is important to use the lowest pressure that will adequately give chest rise to avoid iatrogenic pneumothorax. Term newborns only require 10 to 25 mL of volume per ventilation, so smaller bags should be used with a volume of 200 to 750 mL. The concentration of oxygen should be titrated using an oxygen blender as described in the previous section. The best indicator of successful PPV is increasing heart rate. An acronym for improving PPV is “MRSOPA” (Table 21-5). Effective bag-mask ventilation at 40 to 60 breaths/min is continued for 30 seconds and the infant is then reassessed. Assisted ventilation can be discontinued once the heart rate is >100 beats/min, the infant is breathing spontaneously, and improvements in color and tone are seen. If the heart rate remains <100 beats/min, assisted ventilation is continued. If the heart rate remains <60 beats/min, despite assisted ventilation, chest compressions are initiated and the endotracheal intubation should be considered.2
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Endotracheal Intubation
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The indications for endotracheal intubation during neonatal resuscitation include poor response to or the inability to provide adequate PPV, the need for endotracheal suctioning or chest compressions, extreme prematurity, or suspected diaphragmatic hernia.2 The size of the endotracheal (ET) tube depends on the weight or gestation of the newly born infant (Table 21-6). A laryngoscope with a straight blade is utilized, using a 0 or 1 blade. Successful endotracheal intubation is evidenced by bilateral chest rise and improvement in heart rate, color, and muscle tone. The use of an end-tidal carbon dioxide monitor can assist with confirmation of proper tube placement, even in very low-birth-weight infants. Care must be made not to advance the ET tube too far, which will result in mainstem bronchus intubation. Most ET tubes have a guideline that should be placed adjacent to the vocal cords, resulting in proper intubation depth (Fig. 21-5). A rough formula for depth of intubation is as follows:
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Depth of tube insertion at gums (in cm) = 6 + infant's weight (in kg)2
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Intubation attempts should be completed within 30 seconds during resuscitation because the infant will not be ventilated during the procedure.2