RNC-NIC Thermoregulation 5 — Questions and Answers
Question 1: A mother asks why her healthy term newborn needs a hat. The nurse's BEST response is that a hat primarily prevents heat loss through:
- Conduction to the delivery table
- Radiation and convection from the large surface area of the head (Correct answer)
- Evaporation of amniotic fluid from the scalp
- Absorption of cold air into the fontanelle
Correct answer: Radiation and convection from the large surface area of the head
The head represents a disproportionately large surface area in neonates and loses heat readily via radiation to cooler surrounding surfaces and convection from air currents.
Question 2: A nurse is caring for a 29-week infant in a double-walled incubator. Which intervention MOST effectively reduces radiant heat loss within the incubator?
- Increasing the air temperature of the incubator
- Using a double-walled incubator design (Correct answer)
- Wrapping the infant in warm blankets inside the incubator
- Placing a chemical warming mattress under the infant
Correct answer: Using a double-walled incubator design
The inner wall of a double-walled incubator is warmed by circulating air, reducing the temperature gradient between the infant and incubator walls, thereby minimizing radiant heat loss.
Question 3: During therapeutic hypothermia, a neonate develops coagulopathy. The RNC-NIC understands this complication occurs because cooling:
- Activates the coagulation cascade, causing DIC
- Impairs platelet function and reduces clotting factor activity (Correct answer)
- Increases fibrinogen levels beyond the normal range
- Causes hepatic overproduction of anticoagulant proteins
Correct answer: Impairs platelet function and reduces clotting factor activity
Hypothermia inhibits platelet aggregation and reduces the enzymatic activity of clotting factors, increasing the risk of bleeding.
Question 4: A 27-week infant on servo-control has a set skin temperature of 36.5°C but is found to be hyperthermic (rectal temp 38.2°C). What is the MOST likely cause?
- The servo-control probe is placed over a bony prominence
- The servo-control probe is covered by a warm blanket or is poorly adhered (Correct answer)
- The incubator humidity is set too high
- The infant has increased metabolic activity from feeding
Correct answer: The servo-control probe is covered by a warm blanket or is poorly adhered
When the servo-control probe is insulated (e.g., covered by blankets) or poorly adhered, it reads artificially low, causing the incubator to overheat the infant.
Question 5: Which of the following is a recognized CONTRAINDICATION to therapeutic hypothermia?
- Gestational age of 36 weeks
- Birth weight of 2,100 grams
- Severe coagulopathy present before cooling initiation (Correct answer)
- Apgar score of 3 at 5 minutes
Correct answer: Severe coagulopathy present before cooling initiation
Pre-existing severe coagulopathy is a contraindication to therapeutic hypothermia because cooling further impairs clotting and significantly increases bleeding risk.
Question 6: A NICU nurse is caring for a neonate with persistent pulmonary hypertension (PPHN). The nurse understands that hypothermia in this infant is particularly dangerous because:
- Hypothermia increases pulmonary vascular resistance, worsening right-to-left shunting (Correct answer)
- Hypothermia causes systemic vasodilation that leads to hypotension
- Cold stress increases surfactant production, causing hyperinflation
- Hypothermia reduces systemic vascular resistance, increasing left-to-right shunting
Correct answer: Hypothermia increases pulmonary vascular resistance, worsening right-to-left shunting
Cold stress causes pulmonary vasoconstriction, increasing pulmonary vascular resistance and worsening the right-to-left shunting characteristic of PPHN.
Question 7: A neonate is to be rewarmed after therapeutic hypothermia. The recommended rate of rewarming to minimize neurological harm is:
- 0.1–0.2°C per hour (Correct answer)
- 0.5°C per hour
- 1.0°C per hour
- As rapidly as possible to minimize duration of hypothermia
Correct answer: 0.1–0.2°C per hour
Evidence-based guidelines recommend slow rewarming at 0.1–0.2°C per hour over approximately 6–12 hours to prevent rebound seizures and cerebral hyperemia.
RNC-NIC Thermoregulation 5
A mother asks why her healthy term newborn needs a hat.
The nurse's BEST response is that a hat primarily prevents heat loss through: