What Is Neonatal Hypothermia?

The newborn has a relatively large body surface area, thin subcutaneous fat, many blood vessels, easy heat dissipation, and poor thermal insulation. Central temperature regulation is incompletely developed and the temperature regulation ability is poor. Newborns have underdeveloped muscles, little activity, and poor heat production. When the ambient temperature decreases, warming measures are insufficient, or calorie intake is insufficient, hypothermia easily occurs. Low body temperature can not only cause the skin to be swollen, but also can cause damage to important organ tissues in the body, affect the function, and even cause death in severe cases.

Basic Information

English name: neonatal hypothermia
Visiting department: Neonatal

Common causes: Temperature regulation central immature, affected by cold, disease
Common symptoms: Cold body, low response, lethargy, milk rejection, swollen skin

Causes of neonatal hypothermia

1. Immature central temperature regulation

When the ambient temperature is not enough to keep warm, the intake of calories is too small, and the body temperature cannot be adjusted by adjusting the heat generation.

2. Affected by the cold

The newborn has a relatively large body surface area, which dissipates more heat than it produces heat. When the ambient temperature decreases in winter and spring, it is not effective to keep warm, and hypothermia is most likely to occur.

3. Insufficient food

The amount of glycogen stored in the newborn's liver is very small. If the calorie intake is insufficient, it can be consumed within 18 to 24 hours after birth. Too little heat production, hypothermia easily occurs when the ambient temperature decreases.

4. Premature and low birth weight infants

Less energy reserves, fewer calories, and poorer temperature regulation. The smaller the gestational age, the lower the birth weight, and the greater the risk of hypothermia.

5. Disease impact

When neonates suffer from infectious diseases such as sepsis, pneumonia, and purulent meningitis, due to reduced food intake, insufficient caloric intake; due to shock, acidosis, and microcirculation disorders, which affect brown fat decomposition and reduce body heat production, such as Ambient temperature is too low to keep warm enough, which can easily cause hypothermia. In neonates, when hypoxia and nervous system dysfunction, brown fat cannot be used, and body temperature is not easy to rise.

Clinical manifestations of hypothermia in newborns

When the newborn's body temperature is low, the skin temperature often decreases due to peripheral blood vessel contraction, and the body temperature drops below 35 ° C. First of all, it shows that the whole body is cold and has a low response, lethargy, milk rejection, less crying, and less movement. Some children may have swollen skin, starting in the limbs, thighs, and buttocks, and throughout the body in severe cases.

Tachycardia can occur early, and multiple organ damage can occur in severe cases: slowed breathing, apnea, or even pulmonary hemorrhage, decreased blood pressure, and even death. Nervous system coma, pupil dilation, disappeared to the outside world. Urinary volume was significantly reduced or even anuria, acute renal failure, and diffuse intravascular coagulation. Electrolyte disorders, reduced immune function and severe infections.

Newborn hypothermia

Blood gas content

Significant metabolic acidosis indicates severe hypoxia, poor organ function, and a serious condition.

Blood image

Hematocrit increases, platelet counts decrease significantly, and platelet count reductions often parallel the severity of the disease.

3. Renal failure

Increased serum creatinine and non-urea nitrogen suggest an acute renal failure.

4. ECG

It can be seen that the QRS time is prolonged, the ST segment is prolonged and decreased, and the T wave is sometimes inverted. Arrhythmias can occur.

5.X-ray chest radiograph

Low-temperature infant X-ray chest films without pulmonary complications show clear lung fields and are caused by pulmonary vasoconstriction, such as thickened blood vessel texture, patchy or lumpy shadows, and you should be alert to the possibility of pulmonary bleeding.

6. Microcirculation disorders

The nail cycle microcirculation microscope was used to observe the changes of the nail cycle microcirculation in neonates (low body temperature). It can be seen from the limb blood flow that the limb blood flow velocity becomes slower, indicating that there is indeed a microcirculation disorder when the newborn's body temperature is low.

Neonatal hypothermia diagnosis

1. Have a history of low ambient temperature or improper insulation. At the same time, the situation of primary disease and comorbidities and the intake of calories must be considered.

2. Physical examination: the body temperature is too low, and the anal temperature is lower than 35 ° C. Breathing heart rate slows down and in severe shock.

3. Blood gas analysis includes hypoxia and acidosis, thrombocytopenia in some children, prolonged prothrombin time, decreased blood sugar, and electrolyte imbalance.

4. The T wave of ECG is low, and the ST segment decreases.

5. X-ray chest radiographs may show pulmonary congestion, pulmonary edema and pulmonary hemorrhage.

Neonatal hypothermia treatment

Rewarming

Gradually rewarming, the lower the body temperature, the more caution should be given to rewarming. Re-warming too quickly can cause shock, convulsions, or apnea. Slow rewarming is suitable for children with mild hypothermia, that is, placing the child in a warm room and wrapping it with a warm blanket or small. It is expected to return to normal body temperature within 12 to 24 hours.

Severe hypothermia, slow rewarming is often ineffective. At present, many people advocate external heating and active rewarming to reduce the damage to the body caused by low temperature.

(1) Wrapped in a warm blanket.

(2) Electric heating blanket Set servo control or manual control at 38 40 .

(3) Warm water bath Immerse in 40 ° C warm water for 10 ~ 15min, 1 ~ 2 times / d.

(4) Incubator or radiant heating.

2. Prevention and control of infection

Infection can be a cause of low temperature or a complication. Evidence of infection should be actively sought, and antibiotics given or treated to prevent infection.

3. Feeding and fluid therapy

During the rewarming process, heat should be added, the amount of fluids should be limited, acidosis and microcirculation disorders should be corrected, and blood glucose monitored. The supply of energy should be given at the beginning of rewarming, but because of hypothermia and circulatory disturbances, the digestion and absorption of food are inhibited. Necrotizing enterocolitis, gastroesophageal reflux, endotracheal inhalation and respiratory disturbances may occur. When it is not possible to feed the gastrointestinal tract at low temperatures, parenteral nutrition can be supplemented.

4. Support of the cardiovascular system

In hypothermia, neonatal myocardium is damaged, cardiac dysfunction, and plasma volume increases. Limit fluid volume during rewarming, use diuretics to increase urine output, reduce hypervolemia, and even use positive inotropic drugs.

5. Treatment of pulmonary hemorrhage

A large number of pulmonary hemorrhages occur, and drug treatment is difficult to achieve results. Treatment with artificial respirators can be tried.

6. Primary disease treatment

If hypothermia is only a manifestation of certain diseases of the newborn, it should be actively searched for the cause and treat the primary disease under reasonable environmental temperature and adequate thermal insulation.

Hypothermia prevention

When the newborn is born, the room temperature of the delivery room should be above 25 , and the newborn should be placed on a radiation table after resuscitation. Attention should be paid to keeping warm as soon as the baby is born. Use available warming measures to keep the newborn's ambient temperature as close as possible.

Actively prevent prenatal and postnatal infections.