Newborn Care: Maintaining a Thermal Neutral Environment
Newborn Care: Maintaining a Thermal Neutral Environment
CLINICAL GUIDELINES
Use of selected warming devices to maintain a thermal neutral environment is implemented by the registered nurse (RN) or licensed practical nurse (LPN) with an order from a healthcare prescriber. Follow institutional protocols.
The infant’s temperature is maintained within a specific environmental range, called the thermal neutral zone (TNZ), in which the rates of oxygen consumption and metabolism are minimal and internal body temperature is maintained because of thermal balance. To achieve a thermal neutral environment, regulate warming device to an abdominal wall, flank, or axilla temperature of 97.7°F (36.5°C) or as ordered by healthcare prescriber.
All newborns have their temperature assessed hourly and as needed for the first 4 hours of life.
All infants and children have their temperature assessed as per their acuity level and standard of the unit or institution (see Chapter 123).
EQUIPMENT
Temperature measurement device (see Chapter 123 for types of temperature measurement devices)
Blankets
Head covers
Booties
For radiant warmer:
Radiant warmer
Servo-control temperature probe
For isolette:
Double-walled isolette (Use of porthole sleeves, when available, decreases the amount of ambient heat loss.)
For chemically heated mattress:
Chemically heated mattress
Linen to cover mattress
For heat lamp:
Heat lamp
Yardstick or tape measure
For heat shields or plastic wrap devices:
Plexiglas heat shield
Plastic wrap
Polyethylene/polyurethane bag
For warmed inspired air:
Oxygen tubing
Oxygen flowmeter
Humidification device
CHILD AND FAMILY ASSESSMENT AND PREPARATION
Educate the family regarding the importance of maintaining the infant’s body temperature. Remind the family of the importance of following the guidelines of the American Academy of Pediatrics “Safe Sleep” campaign and that pillows, comforters, and quilts should not be placed in the crib as a means to warm the child.
Discuss the measures that will be used to maintain the infant in a thermal neutral environment:
Explanation of how infant loses heat and tries to maintain heat (Chart 76-1)
Measures used to prevent heat loss
Measures used to provide heat to the infant (heat production)
Manner in which the family can assist with the infant’s care while maintaining the infant’s temperature
Explanation of all equipment to be used to assist in warming the infant
Measures to be used to monitor the infant’s temperature
How to provide skin-to-skin contact (kangaroo care) to the infant
Prewarm isolette or warmer in anticipation for admission of the infant. If delivery of an extremely low-birth-weight infant is anticipated, set delivery room temperature at the appropriate temperature as determined by the delivery room standards; 80°F (26.7°C) is suggested.
CHART 76-1 Temperature Regulation Terms
Conduction—heat transfer from one object to another by direct contact (e.g., x-ray plate, scale, mattress).
Convection—heat loss or increase due to air motion (e.g., cool or warm breezes).
Evaporation—heat loss due to moisture vaporizing from the skin surface (e.g., wet infant at birth or due to bath).
Radiation—heat transfer between objects that are not in direct contact with each other (e.g., incubator placed in direct sunlight).
Thermal neutral zone—an environmental range in which the rates of oxygen consumption and metabolism are minimal for the infant and internal body temperature is maintained because of thermal balance.
Thermogenesis—physiologic mechanisms that increase heat production in the newborn. These include increased basal metabolic rate, muscular activity, and chemical thermogenesis (also called nonshivering thermogenesis).
PROCEDURE Maintaining a Thermal Neutral Environment
Steps
Rationale/Points of Emphasis
1 Perform hand hygiene; don protective apparel (gown and gloves) for care of infant immediately after delivery. Perform hand hygiene after each contact with the infant and before initiating new contact with infant.
Reduces transmission of microorganisms. Protects healthcare provider from exposure to blood and body fluids.
2 Place infant under warming source (on prewarmed warmer or isolette) after birth. Dry infant and remove wet linens. Provide warmed blankets and hat for warmth.
Decreases evaporative heat loss and decreases loss from the head, which is an infant’s largest heat-losing body surface.
3 Determine newborn’s temperature while under warming source.
3a Place servo-control temperature probe over abdominal area, flank, or axilla using foil protective cover; do not place probe where infant will lie on the sensor.
The probe must be in good contact with the skin so that it does not cause false high or low temperatures, thus causing the heating element to react and adversely affect the infant’s temperature. Probe placement on the abdomen, flank, or axilla show no significant temperature differences (Schafer, Boogaart, Johnson, et al., 2014).
3b Correlate probe readout with infant’s temperature when recording vital signs.
Ensures correct patient data are being observed and collected.
caREminder
Do not place probe over stomach area if infant is being fed enterally because the probe will sense the feeding temperature and therefore fluctuate the environment accordingly.
4 Assess temperature hourly for the first 4 hours of life and then as indicated by infant’s acuity level and institutional policy; see Appendix A: Reference Ranges for Vital Sign Measurements for normal ranges. Refer to Chapter 123 for methods to assess temperature.
Ensures that deviation from normal is detected promptly.
5 Offer family the option of skin-to-skin contact, if infant is stable.
Skin-to-skin contact encourages warmth from convection with family member’s body temperature.
6 Give first bath after the infant’s temperature has stabilized in the normal range (98.2°F-99.8°F or 36.8°C-37.7°C axillary) and when appropriate care is taken to support thermal stability (see Chapter 15 ).
Prevents hypothermia that can increase oxygen consumption and respiratory distress.
7a Assess infant. If stable, clothe infant, put on head covering, bundle in blanket, and move infant to open crib for ongoing observations or transfer to mother or father to hold.
Stability is determined by normal vital signs and no signs of respiratory distress. Easy visualization of infant’s chest will aid in prompt detection of increasing respiratory distress. Early transfer to the mother or father promotes parent-infant bonding.
caREminder
Typically, healthy infants who weigh more than 2,300 g can maintain their temperature when covered, as above, in an open crib.
7b Continue to monitor temperature per institutional policy. To prevent exposure and chilling, keep neonate wrapped in a lightweight blanket and accomplish care quickly in a draft-free, warm environment.
Prevents further exposure to cold environment.
8 Provide ongoing warming measures as needed (Figure 76-1).
Prevents hypothermia, which can increase oxygen consumption and respiratory distress. Warming measures are selected on the basis of infant’s temperature, age (premature vs. term), diagnosis, and the resources available.
Figure 76-1 Various methods help newborns maintain thermoregulation: (A) isolette, (B) radiant warmer, (C) plastic wrap, or (D) combination unit, radiant warmer, and isolette.
8a If unable to maintain temperature within normal range and if signs of respiratory distress or other signs need to be closely observed, keep the infant under radiant warmer or move to prewarmed incubator or isolette.
If infant’s axillary temperature is below 97.2°F (36.2°C), rewarming should be initiated. The process should be gradual to prevent the possibility of hyperthermia. Servo-control mode is required for slow rewarming of infant. When the new skin temperature is reached, the air temperature is increased in hourly increments of 1.0°C until the desired skin temperature is reached and infant’s temperature is stable.
8b Follow procedures in Chapter 124 for use of the following warming devices:
• Radiant warmer and isolette
• Chemically heated mattress
• Heat lamp
Ensures that environmental temperature is individualized as appropriate for the infant. Ensures that deviations from normal are detected promptly.
Place warming device and infant in a draft-free environment, out of direct sunlight, to decrease temperature fluctuations due to convection and radiation.
8c For use of plastic wrap as a warming device:
• Stretch wrap over the infant across the plastic sides of radiant warmer.
• Do not place wrap directly on infant’s skin.
Provides barrier to decrease heat loss by convection or evaporation. Contact with infant’s skin may cause maceration or burning.
8d For use of polyethylene/polyurethane bag to prevent heat loss in very low-birth-weight infants:
• After delivery and placement on warmer, immediately place infant in bag up to neck before drying; dry infant’s head and cover with hat.
Decreases evaporative heat loss. If needed, resuscitation can be performed with infant in bag.
8e For use of Plexiglas heat shield as a warming device:
• Place heat shield over infant in incubator or isolette. Do not use when the infant is under radiant warmer.
Decreases radiant heat loss. Under the radiant warmer, the heat shield blocks the infrared heat from reaching the infant.
8f For use of warmed inspired air to aid in thermoregulation:
• Follow procedure for oxygen administration (see Chapter 80 ) to provide warm, humidified, inspired air if infant requires supplemental oxygen.
Provides additional measures to decrease evaporative heat loss and insensible heat loss.
9 Continue to monitor temperature per institutional policy. Continue warming measures as needed.
Provides ongoing assessment and reevaluation of interventions.
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