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Neonatal Pathophysiology > Thermoregulation > Flashcards

Flashcards in Thermoregulation Deck (62)
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When does heat loss via evaporation occur?

when moisture on the surface of the skin or respiratory tract mucosa is converted into vapor- always accompanied with a cooling effect


What facilities heat loss via evaporation?

the cooler the ambient environment, the more rapid the heat loss


What is the effect of increasing incubator humidity?

decreases evaporative losses


How can heat loss via evaporation be minimized?

drying infant, then removing wet blankets, plastic bags at del, increase room temp, eliminate drafts/vents, heating and humidifying the incubator & O2, warming solutions prior to contact with bb, delay bath until body temp has stabilized


What is radiation?

transfer of radiant energy from the body to objects without direct contact


How can heat loss via radiation be minimized?

double walled incubators, pre warming the incubator, keeping incubator away from cooler exterior walls and windows, using isolette cover


How does radiant warmer heat gain occur?

when the surrounding surfaces are warmer than the infant's skin temperature


What is the greenhouse effect?

heat is trapped bc plexiglass walls allow short wave radiation to penetrate the interior, baby will absorb all this short wave heat, but readmits heat as long wave radiation heat which cannot pass through the incubator wall. Long wave heat radiation can be reabsorbed by the infant, and if the cycle is not interrupted, the baby will become hyperthermic (c no incubator temp ∆)


What are the advantages of the radiant warmer?

quickly rewarm, allows direct access for procedures


What are the disadvantages of the radiant warmer?

risk for thermal burns and hyperthermia- ALWAYS USE ON SERVO MODE


What are the advantages of the incubator?

can be used on skin or servo mode, quieter environment, decreases insensible water losses


What are the disadvantages of the incubator?

limited access


What is the process of weaning an infant to the crib?

based on GA and/or weight; a baby hasn't successfully weaned to the crib if they are wearing excessive amt of clothes


What are the benefits of skin to skin?

can be close to the breast for feeding, stabilize VS and oxygenation, improve sleeping patterns and direct social eye contact


What are contraindications for skin to skin?

physiologic instability


What is the clinical presentation of hypothermia?

pale, cool to the touch, acrocyanosis, respiratory distress, apnea, bradycardia, central cyanosis, irritability progressing into lethargy, progressive or chronic cold stress


What is the clinical progression of hypothermia?

progressive, peripheral vasoconstriction is the first response, then O2 consumption will increase, then progresses into A/B/central cyanosis


How does an infant present with chronic cold stress?

a weak cry, hypotonia, increased gastric residuals, abdominal dissension, poor feeding and poor weight gain


What is the physiologic response to cold stress?

vasoconstriction, brown fat metabolism and increased muscle activity and flexion


How will a term infant utilize muscle activity and flexion in a hypothermic state?

a term babe can increase muscles activity to increase heat and flex to decrease the surface area exposed to cooler environmental temperatures


How does vasoconstriction affect core body temperature?

shunting blood away from the skin surface into the body core, even with mild hypothermia


What happens to the metabolic rate in an infant with hypothermia?

metabolic rate increases in an effort to produce heat and conserve heat which in turn increases O2 consumption and glucose utilization; significant risk of conversion to anaerobic metabolism which will increase lactic acid built up


How is the respiratory system affected by hypothermia?

if already experiencing RDS, an increase in O2 demand may worsen distress and lead to hypoxemia


What conditions should be included in your differential diagnosis of temperature instability?

sepsis, hypothermia r/t prematurity and inappropriate environment, use of equipment, misuse of equipment


What is the recommended rate of rewarming an infant?

rate should be specific to each individual infant- depending on their tolerance; no evidence to give a specific rate; don't exceed 0.5 degrees/hr


What should be monitored while rewarming an infant?

vital signs, level of consciousness, acid/base status


If utilizing a radiant warmer to rewarm an infant, what should be remembered?

with exposed skin, blood vessels are sensitive to heat (skin warms quicker than core), risk is warmer in response to cold baby temp will operate on full heat output


What is the risk of warming an infant too quickly?

rapid heating can cause vasodilation and a rapid drop in BP- if infant's status begins to deteriorate, then the rate of warming needs to be ∆


What is the clinical presentation of hyperthermia?

warm to the touch, pink/ruddy (r/t vasodilation), tachypnea, apnea, tachycardia, weak cry, hypotonia, irritable, lethargic, poor feeding, sz, may have perspiration, hypotension


What is the etiology of hyperthermia in neonates?

equipment use/misuse, remove iatrogenic etiology- bundling, direct sunlight, phototx, etc; sepsis, CNS abnormalities or dehyradtion