Nursing diagnosis: ineffective thermoregulation may be related to immature CNS development (temperature regulation center), decreased ratio of body mass to surface area, decreased subcutaneous fat, limited brown fat stores, an inability to shiver or sweat, limited/inability to flex extremities, poor metabolic reserves (limited glycogen stores), thinner skin, muted response to hypothermia, and frequent medical/nursing manipulations and interventions possibly evidenced by fluctuation of body temperature below/above normal range, tachypnea/apnea, generalized cyanosis, bradycardia, lethargy (cold stress), and tachycardia, flushed color, lethargy, apnea (hyperthermia).
Desired Outcomes: Maintain skin/axillary temperature within 97.7°F–99.1°F (36.5°C–37.3°C). Be free of signs of cold stress.
Nursing intervention with rationale:
1. Assess temperature frequently. Check rectal temperature initially; thereafter, check axillary temperature or use thermostat probe with open bed and radiant warmer. Repeat every 15 min during rewarming.
Rationale: Hypothermia predisposes infant to cold stress, utilization of nonrenewable brown fat stores if present, and reduced sensitivity to increased levels of carbon dioxide (hypercapnia) or decreased oxygen levels (hypoxia). Note: Too rapid rewarming is associated with apneic states. This causes further respiratory depression instead of increased respiratory rate, leading to apnea and reduced oxygen uptake.
2. Ascertain medications mother received during prenatal and intrapartal periods. Note presence of fetal distress or hypoxia.
Rationale: Fetal hypoxia or maternal use of meperidine (Demerol) alters fetal metabolism of brown fat, often causing significant drop in neonate’s temperature. Magnesium sulfate can cause vasodilation and interfere with infant’s ability to retain heat.
3. Place infant in warmer, Isolette, incubator, open bed with radiant warmer, or open crib with appropriate clothing for larger or older infants. Use heating pad under infant as necessary, in conjunction with Isolette or open bed.
Rationale: Maintains thermoneutral environment, helps prevent cold stress.
4. Use heat lamps during procedures. Warm objects coming in contact with infant’s body, such as stethoscopes, linens, and clothing. Use blanket/diaper to pad cold surfaces such as scale, examination table, x-ray plate, and hands. Surround infant with warmed receiving blankets. Cover radiant warmers with plastic wrap, if appropriate. Warm blood products, if administered.
Rationale: Decreases loss of heat to the cooler environment of the room/treatment surfaces, or by infusion of chilled blood.
5. Reduce exposure to drafts; avoid unnecessary opening of portholes in Isolette.
Rationale: Reduces heat losses due to convection/conduction. Limits heat losses from radiation.
6. Change clothing or bed linens when wet. Keep infant’s head covered.
Rationale: Decreases evaporative losses.
7. Note environmental temperature/monitor temperature-regulating system, radiant warmers, or incubators. (Maintain upper limit at 98.6°F [37°C], depending on infant’s size or age.)
Rationale: Hyperthermia with resultant increases in metabolic rate, oxygen and glucose needs, and insensible water losses can occur when controlled environmental temperatures are too high. Conversely, a decrease in the environmental temperature of 3.6°F (2°C) also results in significant increase of oxygen consumption and glucose needs.
8. Maintain relative humidity of 50%–80%. Warm humidified oxygen to 88°F–93°F (31°C–34°C).
Rationale: Prevents excessive evaporation, reducing insensible fluid losses.
9. Note presence of tachypnea or apnea; generalized cyanosis, acrocyanosis, or mottled skin; bradycardia, poor cry, or lethargy. Evaluate degree and location of jaundice.
Rationale: These signs indicate cold stress, which increases oxygen and caloric consumption and predisposes infant to acidosis associated with anaerobic metabolism. Hypothermia increases risk of kernicterus, as fatty acids released with brown fat metabolism compete with bilirubin for binding sites on albumin. Note: Skin color may be bright red peripherally, with cyanosis noted centrally as a result of failure of dissociation of oxyhemoglobin.
10. Provide supplemental oxygen as indicated.
Rationale: If oxygen is not readily available to meet increased metabolic needs associated with efforts to increase body temperature, the infant will use anaerobic metabolism, resulting in acidosis caused by lactic acid buildup. Hypothermia reduces the preterm infant’s response to hypoxia and hypercapnia, which causes further respiratory depression instead of increased respiratory rate, leading to apnea and reduced oxygen uptake. Hyperthermia caused by too rapid/excessive warming is associated with apneic states, increased insensible water losses, and increased metabolic rates with increased demands for
oxygen and glucose.