An infant weighing 1600 g (3 1/2 lb) is born at 32 weeks' gestation. Initial evaluation was benign, and the infant was transferred to the level 2 nursery for prematurity. The nurse there calls at 1 hour of life and reports the infant is tachypneic. Vital signs include a heart rate of 140 beats per minute, a respiratory rate of 80 breaths per minute, a temperature of 35degC (95degF), and a peripheral oxygen saturation of 98%. The lungs are clear with bilateral breath sounds and there is no murmur; the infant is in no distress. The child's chest radiograph is shown. Which of the following is the most appropriate next step in evaluating the infant?
(d) Source: (Hay et al, pp 30-31. Kliegman et al, pp 536-537. McMillan et al, p 259. Rudolph et al, pp 171-172.) The radiograph is normal. However, the vignette describes a cold infant. A room temperature of 24degC (approximately 75degF) provides a cold environment for newborn infants. Aside from the fact that these infants emerge from a warm, 37.6degC (99.5degF) intrauterine environment, at birth, infants (and especially preterm infants) are wet, have a relatively large surface area for their weight, and have little subcutaneous fat. Within minutes of delivery, the infants are likely to become pale or blue and their body temperatures will drop. In order to bring body temperature back to normal, they must increase their metabolic rate; ventilation, in turn, must increase proportionally to ensure an adequate oxygen supply. Because a preterm infant is likely to have respiratory problems and be unable to oxygenate adequately, lactate can accumulate and lead to a metabolic acidosis. Infants rarely shiver in response to a need to increase heat production. If the tachypnea persists after warming the infant, sepsis, pneumonia, and primary surfactant deficiency are all possible; several of the alternative answers then may be appropriate.
Obtain a complete blood count and differential.
Perform a lumbar puncture.
Administer intravenously 5cc of D50W.
Place the infant under a warmer.
New Born Infants