5.2 Thermal Regulation | Neonatology Academy

Bedside Action Box — First Response to Any Abnormal Temperature

Target: axillary temperature 36.5–37.5°C · Treat instability as a clinical sign, not just an equipment problem

Repeat and verify the measurement, preferably axillary unless local policy specifies another route.
Look at the baby: perfusion, respiratory effort, oxygen need, activity, glucose risk, feeding tolerance, and recent procedures.
Check the environment: room temperature, drafts, open incubator portholes, wet linen, phototherapy, over-wrapping, radiant warmer, plastic wrap, mattress, and humidifier status.
Correct the modifiable heat-loss or heat-gain factor immediately, then recheck temperature at an appropriate short interval.
Escalate if the baby is unwell, very preterm, persistently unstable, febrile, or hypothermic despite environmental correction — evaluate for illness.

1. Overview

Thermal regulation is a core neonatal safety function, not a nursing comfort measure. Newborns — especially preterm and low-birth-weight infants — lose heat quickly because they have a large surface-area-to-weight ratio, thin skin, limited insulation, immature vasomotor control, and reduced energy reserves.

The goal is to prevent both hypothermia and hyperthermia while maintaining a neutral thermal environment that minimizes oxygen consumption and metabolic stress. The bedside target is normothermia: axillary or core temperature around 36.5–37.5°C.

Temperature instability is a clinical sign

A single abnormal value should trigger both an environmental check and a clinical assessment, because temperature instability may be the first sign of infection, poor perfusion, hypoglycemia, respiratory distress, or excessive iatrogenic heat exposure. Do not treat it as only an incubator problem.

2. Definitions and Temperature Targets

Category	Temperature	Bedside Meaning	Immediate Action
Normothermia	36.5–37.5°C	Preferred target range for term and preterm infants unless therapeutic cooling is intentionally prescribed	Continue routine monitoring and maintain current thermal strategy
Mild hypothermia / cold stress	36.0–36.4°C	May be environmental or early illness; preterm infants can decompensate quickly	Add heat support, assess baby, remove heat-loss sources, recheck within ~1 hour or per unit protocol
Moderate/severe hypothermia	<36.0°C	Higher risk of hypoglycemia, apnea, acidosis, respiratory deterioration, and sepsis mimicry	Medical review, controlled rewarming, glucose check, cardiorespiratory monitoring, illness evaluation
Low-grade fever / overheating	37.6–37.9°C	Often environmental, but trend and clinical status matter	Remove excess heat, lower incubator/warmer support gradually, reassess clinical status, repeat temperature
Fever	≥38.0°C	Treat as possible illness until proven otherwise, especially in a NICU infant	Medical review; assess infection risk, immunization timing, withdrawal, dehydration, environmental overheating, and local sepsis pathway

Measurement Principles

Axillary temperature is commonly used for routine neonatal monitoring — practical, repeatable, and avoids rectal trauma risk.
Measure on admission or within 60 minutes of birth, then hourly until stable; once stable, 3–4 hourly or per local protocol.
In infants with poor perfusion, a large central-peripheral temperature gap may support concern for low cardiac output — interpret with the full clinical picture.
Use the same site and method for trending whenever possible; unexpected values should be repeated and checked against the infant's appearance.

3. Heat-Loss Physiology and Cold-Stress Consequences

Table — Four Mechanisms of Heat Loss

Mechanism	How It Happens in the NICU	High-Risk Example	Prevention
Evaporation	Water evaporates from wet skin, amniotic fluid, bathing, wet linens, or exposed immature skin	<32-week infant placed under warmer without plastic wrap or humidity	Dry term infants quickly; for very preterm infants, dry head only and place body in polyethylene wrap/bag per protocol
Convection	Heat lost to moving cooler air, drafts, open doors, oxygen flow, or room air around exposed skin	Infant transported uncovered or cared for near a door/window	Warm room, reduce drafts, close incubator portholes, cover exposed skin, warm/humidify respiratory gases
Conduction	Heat transfers to cold surfaces: scales, mattresses, towels, X-ray plates, or procedure tables	Newborn weighed on an unprotected cold scale	Prewarm surfaces; place a warm blanket or barrier between baby and cold equipment
Radiation	Heat lost to nearby cold walls, windows, incubator surfaces, or large objects without direct contact	Infant nursed near a cold window or cold incubator wall	Keep beds away from windows, prewarm incubators, and use covers or appropriate thermal barriers

Clinical Consequences of Cold Stress

System	What Cold Stress Can Cause	Bedside Implication
Metabolic	Increased O₂ consumption, glucose use, lipolysis, and risk of hypoglycemia	Check glucose in at-risk infants or moderate/severe hypothermia
Respiratory	Increased oxygen demand, tachypnea, apnea, worsened respiratory distress, and acidosis	Do not assume deterioration is purely pulmonary if temperature is low
Cardiovascular	Peripheral vasoconstriction, pulmonary vasoconstriction, impaired perfusion, and metabolic acidosis	Assess perfusion and lactate in sick or very preterm infants
Neurologic/developmental	Stress, agitation, altered sleep, and potential instability during handling	Cluster care wisely and use containment; avoid excessive handling during rewarming
Infection/illness signal	Hypothermia or fever may represent sepsis, not just environment	Persistent or unexplained instability requires medical evaluation

4. High-Risk Infants and Prevention Bundles

Infants at Highest Thermal Risk

Extremely preterm and very preterm infants, especially <32 weeks or <1250 g
ELGAN infants with immature skin, high transepidermal water loss, and limited brown fat
Small-for-gestational-age or growth-restricted infants with reduced fat stores
Infants needing resuscitation, respiratory support, central access, surgery, prolonged procedures, or transport
Infants with sepsis, shock, hypoglycemia, HIE outside intentional cooling, endocrine disease, or significant illness
Infants exposed to cold operating rooms, delayed drying, wet linens, open portholes, or disconnected humidified respiratory gas

Prevention Bundle by Location

Location	Core Actions	Extra Actions for Preterm/ELBW	Avoid
Delivery room / OR	Warm room, preheated radiant warmer, warm towels, hat, skin-to-skin for stable eligible infants	For <32 weeks: dry head only, place body in polyethylene bag/wrap, use hat, thermal mattress if local policy, warmed humidified gases when available	Wet linens, cold scales, drafts, unnecessary early bath, prolonged exposure, overheating from combined devices without monitoring
Transport to NICU	Use warmed transport incubator or suitable thermal support; cover infant; minimize stops and exposure	Maintain plastic wrap/bag until incubator humidity is established when appropriate; use warmed gases and monitor temperature	Moving through cold corridors without thermal support; opening transport incubator repeatedly
NICU admission	Place high-risk infants into prewarmed incubator or radiant warmer; verify servo probe position; document admission temperature	Use humidified incubator for very preterm infants per local age/weight policy; avoid prolonged open access	Assuming admission temperature is only a nursing metric — it is an outcome predictor and quality measure
Procedures and imaging	Prewarm equipment and surfaces, use containment, keep exposure brief, recheck temperature after prolonged procedures	For ELBW infants, plan the entire procedure before exposing the baby; use two-person care when possible	Leaving infant uncovered during X-ray, line placement, ultrasound, or weighing
Open crib / discharge	Dress, swaddle, use hat when needed, maintain safe sleep positioning, document stable temperatures	Delay open crib transition until feeding, weight gain, respiratory stability, and temperature stability are adequate	Using unsafe sleep positioning at discharge to solve temperature problems

5. Delivery-Room, Transport, and NICU Admission Care

Delivery-Room Thermal Sequence

Sequence at birth

Before birth: warm the room, preheat radiant warmer, prepare hat, plastic wrap/bag if preterm, thermal mattress if used, and warmed humidified gases if respiratory support is expected.
Term/larger stable infants: dry thoroughly, remove wet towels, place skin-to-skin when appropriate, cover with warm dry blanket, and support early breastfeeding.
Very preterm infants: avoid full drying of the body; dry the head only, place the wet body in polyethylene wrap/bag under the radiant warmer, place hat, and attach temperature monitoring early.
Before leaving DR: obtain or confirm temperature when feasible, secure airway/lines, prevent exposure during transfer, and communicate thermal risk to the receiving team.

Transport Principles

Use a warmed transport incubator or equivalent thermal support for preterm, sick, or low-birth-weight infants.
Keep the infant covered during movement and avoid repeated opening of the transport incubator.
Use warmed humidified gases during respiratory support when available and appropriate.
Measure temperature promptly after arrival and document whether the infant arrived normothermic, cold, or overheated.

NICU Admission Thermal Setup

Infant Group	Preferred Initial Thermal Support	Key Nursing/Medical Checks
<32 weeks and/or VLBW	Prewarmed hybrid incubator or radiant warmer for access, with humidified incubator strategy when feasible	Servo probe attached correctly, axillary temperature trend, humidity ordered, plastic wrap removed only when incubator humidity is ready
<29 weeks and/or <1250 g	Incubator humidity commonly ~80% during the first week, then gradual weaning by local protocol	Daily skin integrity, adhesive reliability, fluid balance, sodium trend, weight, and infection-control precautions
32–35 weeks or >1250 g but still immature	Prewarmed standard incubator or hybrid incubator depending on stability	Avoid over-bundling; transition as heat requirement decreases and physiologic stability improves
>35 weeks or larger stable infant	Open crib or radiant warmer if observation/access required	Support skin-to-skin, safe sleep, and frequent reassessment if temperature trend is borderline
Sick term or postoperative infant	Radiant warmer or incubator based on access needs, perfusion, procedures, and monitoring	Do not dismiss hypothermia or fever as environmental until sepsis/shock/respiratory status is considered

5+. Heat-Loss Distribution and Neutral Thermal Environment Tables (Baylor Ed. 33)

The scale of the problem in the delivery room

Estimated heat loss in the delivery room may reach 200 kcal/kg per minute — far more than a newborn can possibly produce. Core temperature can fall 2 °C (3.6 °F) within 15 minutes of birth. This is why drying, removing wet linen and pre-warming the surface are not optional niceties: they are the intervention.

Route of heat loss	At 30 °C (86 °F) room	At 33 °C (91 °F)	At 36 °C (97 °F)
Radiation — cool room and walls	43%	40%	34%
Convection — breezy air currents	37%	33%	19%
Evaporation — not dried quickly	16%	24%	56%
Conduction — cold blankets on a warmer	5%	3%	1%

Baylor Table 5-1. Note how the dominant mechanism shifts: in a cool room radiation dominates, but in a warm room evaporation becomes more than half of all loss — so a warm delivery room does not excuse leaving an infant wet.

Numbers to set the equipment by

Delivery room air 23–25 °C (74–77 °F) (NRP 8th edition); neonatal unit room temperature 22–26 °C (72–78 °F).
Axillary target 36.5–37.4 °C in an open crib; core 36.5–37.5 °C. Keep a non-asphyxiated newborn between 36.5 and 37.5 °C from birth through admission and stabilization. Avoid hyperthermia above 38.0 °C.
Servo skin set point 36.2–36.5 °C on the anterior abdominal wall — this approximates the neutral thermal environment with minimal oxygen consumption. If the set point has to go below 36.2 °C to keep the axillary temperature under 37.5 °C, with working equipment and no infection, the infant is probably too mature for servo control — move to a manual-control incubator or an open crib.
Rewarm an unintentionally hypothermic newborn slowly, about 0.5 °C per hour. Apnoea and hypoglycaemia can occur during rewarming even in mature infants.
Radiant warmer manual mode: avoid it because of the overheating risk; if used to pre-warm the bed, do not set heater power above 75% of maximum.
Oxygen consumption can rise to 2.5 times basal at an air temperature of 28–29 °C (82–84 °F). Measured oxygen consumption is the best indicator of the balance between heat loss and heat production — and hypoxia inhibits the metabolic response to cold, so a hypoxic infant cannot defend its temperature.
By device: below 32 weeks or 1250 g → pre-warmed convertible incubator (humidity 80% for the first 7 days if under 1250 g or 29 weeks, keeping the plastic wrap on until the humidity target is reached); 32–35 weeks and above 1250 g → pre-warmed standard incubator; above 35 weeks or 1700 g → pre-warmed radiant warmer or open crib.

Age	<1200 g	1200–1500 g	1500–2500 g	>2500 g and >36 weeks corrected
0–6 h	35.0 (34–35.4)	34.1 (33.9–34.4)	33.4 (32.8–33.8)	32.9 (32–33.8)
6–12 h	35.0 (34–35.4)	34.0 (33.5–34.3)	33.1 (32.2–33.8)	32.8 (31.4–33.8)
12–24 h	34.0 (34–35.4)	33.8 (33.9–34.3)	32.8 (31.8–33.8)	32.4 (31–33.7)
24–36 h	34.0 (34–35)	33.6 (33.1–34.2)	32.8 (31.6–33.6)	32.1 (30.7–33.5)
36–48 h	34.0 (34–35)	33.5 (33–34.1)	32.5	31.9
48–72 h	34.0 (34–35)	33.5 (33–34)	32.3 (31.2–33.4)	31.7 (30.1–33.2)
72–96 h	34.0 (34–35)	33.5 (32–34)	32.3 (31.1–33.2)	31.3 (29.8–32.8)
4–12 days	<1500 g: 33.5 (33–34)		32.1 (31–33.2)	4–5 d 31.0 · 5–6 d 30.9 · 6–8 d 30.6 · 8–10 d 30.3 · 10–12 d 30.1
12–14 days	<1500 g: 33.5 (32.6–34)		32.1 (31–33.2)	29.8 (29–30.8)
2–3 weeks	<1500 g: 33.1 (32.2–34)		31.7 (30.5–33)	—
3–4 weeks	<1500 g: 32.6 (31.6–33.6)		30.9 (30–32.7)	—
4–5 weeks	<1500 g: 32.0 (31.2–33)		30.9 (29.5–32.2)	—
5–6 weeks	<1500 g: 31.4 (30.6–32.3)		30.4 (29–31.8)	—

Baylor Table 5-2 — suggested starting incubator air temperature in °C (range in brackets) approximating a neutral thermal environment, adapted from Klaus and Fanaroff, Care of the High-Risk Neonate. These are starting points to be adjusted by the infant's measured temperature, not values to be maintained regardless of what the baby does. A few printed sub-ranges in the source do not bracket their own starting value; where that happens, trust the starting temperature and titrate.

6. Equipment Strategy: Incubators, Radiant Warmers, Plastic Wrap, and Humidity

Device and Mode Comparison

Device / Mode	Best Use	Advantages	Risks / Safeguards
Servo-control incubator	Small, immature, or unstable infants needing tight thermal regulation	Responds to skin probe temperature; can minimize metabolic demand when properly used	Probe displacement → overheating or underheating; always correlate with axillary temperature and infant exam
Air-control incubator	Maturing stable infants with decreasing heat needs	Useful step before open crib; allows controlled reduction in ambient heat	Air temperature should be reduced gradually and guided by infant temperature, growth, feeding, and stability
Radiant warmer	Delivery room, procedures, unstable infants requiring frequent access	Excellent access and rapid heat replacement	Increases evaporative water loss; use servo control; avoid prolonged exposure without humidity or wrap in ELBW infants
Hybrid incubator	ELBW/VLBW infants requiring both access and humidified closed care	Supports high humidity, thermal stability, and easier transition between open and closed modes	Open mode loses humidity and increases evaporative losses; minimize open time
Polyethylene wrap/bag	Very preterm DR stabilization before incubator humidity is established	Reduces evaporative heat and water loss	Can contribute to hyperthermia if combined with other heat sources without monitoring
Thermal mattress / heated pad	Selected high-risk deliveries or transports per local policy	Additional heat source when standard measures are insufficient	Avoid stacking heat sources without continuous temperature vigilance and skin checks

Humidity Strategy

Humidity reduces transepidermal water loss and evaporative heat loss in extremely preterm infants. It is most useful in the first week of life when the skin barrier is immature. A common approach: high humidity for infants <29 weeks and/or <1250 g, with gradual weaning after the first week. Local policy defines exact thresholds, targets, and discontinuation timing.

Humidity Phase	Typical Purpose	Bedside Cautions
First days of life	Reduce evaporative heat and water loss in ELGAN/VLBW infants	Monitor skin, sodium, fluid balance, dressing adherence, condensation, and infection-control practice
Weaning phase	Gradually expose maturing skin to lower humidity while maintaining temperature and fluid stability	Avoid abrupt humidity reduction that increases insensible water loss
Discontinuation	Transition to standard incubator environment when skin maturity and temperature stability allow	Recheck weight trend, urine output, sodium, and temperature after changes

7. Management of Hypothermia, Fever, and Temperature Instability

Hypothermia Response Algorithm

Step-by-step

Confirm the value: repeat axillary temperature, check thermometer function, compare with clinical appearance.
Assess severity: 36.0–36.4°C vs. <36.0°C, and identify whether the infant looks well or unwell.
Correct environmental causes: wet linen, drafts, cold surfaces, open incubator ports, low incubator temperature, disconnected humidifier, or insufficient clothing.
Add thermal support: hat, swaddle, warmed blanket, skin-to-skin for eligible stable infants, incubator, radiant warmer, or heated mattress if local policy allows.
Check glucose and cardiorespiratory status in at-risk infants, moderate/severe hypothermia, or any infant with poor feeding, apnea, lethargy, or respiratory distress.
If <36.0°C, persistent, recurrent, or associated with illness: request medical review and consider sepsis/shock/metabolic evaluation.

Rewarming Principles

Situation	Approach	Precautions
Well infant with mild hypothermia	Remove heat-loss source; add clothing/hat/swaddle or skin-to-skin; repeat temperature within ~1 hour	Do not overheat; reassess feeding and glucose risk
Infant <36.0°C or preterm/VLBW	Use incubator or radiant warmer with controlled monitoring; consider slower rewarming for <1200 g	Monitor apnea, glucose, perfusion, and temperature trend
Unwell infant at any temperature	Treat as clinical deterioration; stabilize airway, breathing, circulation, glucose; evaluate for sepsis/shock	Do not delay antibiotics or resuscitation while adjusting environmental heat
Infant under multiple heat sources	Use minimum effective combination with continuous monitoring when devices are combined	Avoid hyperthermia and skin injury; check probe placement

Hyperthermia / Fever Response Algorithm

Never rapidly cool a newborn outside an intentional therapeutic hypothermia protocol

Aim to return to normothermia safely. Do not apply ice packs, cold water, or rapid cooling methods outside a designated HIE/cooling program.

Confirm temperature and check if the infant is clinically well or unwell.
Look for environmental heat gain: excessive wrapping, phototherapy, plastic wrap, radiant warmer, thermal mattress, incubator set point, probe displacement, or room temperature.
If 37.6–37.9°C and well: remove excess layers or reduce incubator/warmer support gradually and recheck.
If ≥38.0°C, persistent, or infant is unwell: notify medical staff and evaluate for infection, dehydration, immunization reaction, withdrawal, neurologic injury, or environmental overheating.

8. Weaning to Open Crib and Discharge Readiness

Weaning thermal support is a developmental milestone and a discharge-readiness step. The goal is not only a normal temperature once, but sustained thermal stability while the infant is feeding, growing, breathing comfortably, and being handled in a realistic home-like environment.

Transition Step	Suggested Readiness Features	Monitoring After Transition
Servo-control → air-control mode	Clinically stable, decreasing heat requirement, often at least ~1250 g, tolerating dressing/diaper/blanket	Frequent axillary temperatures; check probe removal does not mask instability
Air-control incubator → open crib	Often ~>1500 g or >34 weeks, tolerating feeds, gaining weight for several days, minimal apnea/bradycardia, physiologically stable, incubator air temperature ~28–28.5°C for several hours	Frequent early temperatures, then routine schedule once stable; monitor feeding endurance and weight
Open crib → discharge readiness	Sustained normal axillary temperature in clothes/swaddle, adequate weight gain, safe sleep positioning, mature feeding, stable respiratory control	Parent education: home room temperature, avoiding over-bundling, fever/hypothermia warning signs, and when to seek care

Do not advance thermal weaning when

Baylor Ed. 33 puts exact numbers on the criteria above. Servo → air control when the infant is stable, the heat requirement is falling and weight is at least 1250 g, dressed in clothes, hat, nappy and/or blanket — some rapidly maturing infants skip this step because servo control has already brought incubator air down to around 28.5 °C. Air control → open crib when the infant is over 1500 g or over 34 weeks, tolerating enteral feeds, with five days of consistent weight gain (10–20 g/kg/day below 38 weeks, 20–30 g/kg/day above 38 weeks), only occasional brief apnoea or bradycardia, physiological stability, and a minimum incubator air temperature of 28 °C for at least 8 hours. Consider the infant's size — LGA, SGA, mature preterm and growth-restricted infants behave differently. Delay has a cost: late weaning to an open crib prolongs hospitalization and delays full oral feeding.

Humidity weaning: 80% for infants under 29 weeks but over 24 weeks, and/or under 1250 g, for the first 7 days — consider 70% if adhesive dressings will not hold. From day 7, wean by 5% every 12 hours until 50% (about day 10), and discontinue by day 14. Keep the plastic wrap on until the incubator reaches its humidity target.

The infant has recurrent hypothermia, persistent oxygen escalation, frequent apnea/bradycardia, poor feeding endurance, new sepsis concern, or poor weight gain.
The infant needs prolonged procedures, major respiratory changes, or postoperative stabilization.
The incubator temperature remains high or frequent environmental adjustments are required to keep the baby normothermic.

9. Thermal Regulation Checklist for Rounds

Question	Why It Matters	Acceptable Answer	Escalate If…
What was the admission temperature?	Admission hypothermia is linked to morbidity and mortality in preterm infants	Documented and within target or corrected with clear plan	Missing, <36.5°C, >37.5°C, or recurrent instability
Is the infant in the right device/mode?	Thermal support should match gestation, weight, acuity, and access needs	Incubator, radiant warmer, or open crib chosen intentionally	Unexplained high heat need, frequent alarms, or unstable temperature
Is humidity appropriate?	ELGAN infants lose water and heat through immature skin	Humidity target ordered and being weaned per policy	Hypernatremia, excessive weight loss, poor skin integrity, or condensation problems
Are procedures causing heat loss?	Line placement, X-ray, ultrasound, and cares can destabilize ELBW infants	Prewarmed supplies, exposure minimized, post-procedure temperature checked	Repeated low temperature after procedures
Is the baby ready for open crib?	Early weaning may fail; late weaning can delay discharge	Stable temperature, feeding, weight gain, and respiratory status	Temperature instability, poor growth, or ongoing cardiorespiratory events

10. Source Differences and How to Use Them

Topic	Baylor Emphasis	West Midlands Emphasis	Neonatology Academy Synthesis
Room temperature	NICU 22–26°C; NRP-linked thermoregulation in delivery room	Delivery room 23–28°C, especially higher for premature infants	Use local policy; warm the room before high-risk birth; avoid drafts. Higher ambient targets may be needed for ELGAN/IUGR deliveries
Very preterm delivery care	Plastic wrap, hats, warmed humidified gases, high humidity after admission	<32 weeks: dry head only, plastic bag, hat, temperature before transfer	Combine measures: warm room, wrap/bag, hat, prewarmed surface, rapid transfer, and early temperature documentation
Incubator weaning	Open crib often when >1500 g or >34 weeks with feeding, weight gain, stability, and low incubator air temperature	Open cot around 1600 g in their local pathway	Weight alone is insufficient; use physiologic stability, feeding, growth, apnea burden, and temperature trend
Rewarming	Slow rewarming may be prudent; monitor apnea/hypoglycemia	Rewarm in incubator; ≥1200 g may rewarm faster than <1200 g	Use controlled rewarming; smaller or sicker infants need slower, closely monitored correction
Hyperthermia	Avoid >38°C, especially with multiple thermal devices	Treat fever or persistent instability as possible illness, not only overheating	Reduce environmental heat safely and evaluate illness when fever, unwell appearance, or persistent instability is present

11. Common Mistakes

Treating temperature as a number only, without examining perfusion, respiratory status, glucose risk, and infection risk.
Drying the whole body of a very preterm infant before placing in plastic wrap — thereby losing the benefit of evaporative heat-loss prevention.
Combining plastic wrap, thermal mattress, radiant warmer, and high room temperature without frequent temperature checks.
Leaving incubator portholes open during procedures or family visits.
Assuming fever is environmental in a NICU infant without assessing sepsis, dehydration, recent immunization, and clinical appearance.
Moving to open crib based on weight alone despite poor feeding, apnea, low incubator air temperature not yet achieved, or inconsistent weight gain.
Using unsafe sleep practices near discharge to compensate for borderline temperature.

12. Teaching Points

The neutral thermal environment is the temperature environment that minimizes metabolic demand while keeping the infant normothermic.
Hypothermia increases oxygen and glucose consumption; the smaller and sicker the infant, the less reserve the baby has.
Admission temperature is a quality marker — it reflects delivery-room preparation, transfer safety, and early NICU practice.
Very preterm infants need evaporative-water-loss prevention as much as heat replacement; humidity and plastic wrap are physiologic tools, not cosmetic practices.
Temperature instability may be the earliest sign of sepsis or shock — persistent abnormal values should not be treated as an incubator problem alone.
Open crib readiness requires temperature stability plus feeding maturity, growth, and respiratory stability.

Thermal Regulation