Neonatal Hypothermia: IAP Guidelines

Thermoregulation is the ability to maintain balance between heat production and heat loss in order to sustain body temperature within a normal range.

The Indian Academy of Pediatrics (IAP) has released Standard Treatment Guidelines 2022 for Neonatal Hypothermia. The lead author for these guidelines on Neonatal Hypothermia is Dr. Somashekhar Nimbalkar along with co-author Dr. Akumtoshi and Dr. Ravi Shankar Swam. The guidelines come Under the Auspices of the IAP Action Plan 2022, and the members of the IAP Standard Treatment Guidelines Committee include Chairperson Remesh Kumar R, IAP Coordinator Vineet Saxena, National Coordinators SS Kamath, Vinod H Ratageri, Member Secretaries Krishna Mohan R, Vishnu Mohan PT and Members Santanu Deb, Surender Singh Bisht, Prashant Kariya, Narmada Ashok, Pawan Kalyan.

Following are the major recommendations of guidelines:

The World Health Organization (WHO) defines neonatal hypothermia as an axillary temperature below 36.5°C (97.7°F) among newborns aged below 28 days. Normal axillary temperature is 36.5–37.5°C.

Mild hypothermia/cold stress 36.0–36.4°C

Moderate hypothermia 32.0–35.9°C

Severe hypothermia <32°C.

Risk Factors:

Prematurity, low birth weight, intrauterine growth restriction (IUGR), asphyxia, and congenital defects like abdominal wall defects.

Low delivery room temperature, not drying the neonate during postdelivery care, bathing the newborn after birth, removal of vernix caseosa, reduced contact with mother, and delayed initiation of breastfeeding are risk factors for neonatal hypothermia, especially in developing countries.

Poor understanding of healthcare providers about the physiology of thermoregulation is a contributory factor too.

Low ambient temperature as well as lower maternal temperature are known risk factors. Neonatal transport is almost always done poorly and is a risk factor for hypothermia.

Procedures for neonatal care such as surgery, placement of umbilical lines, and radiological investigations such as MRI are associated with neonatal hypothermia.

Prevalence:

Across the gestational age spectrum of newborns that are cared for in various settings (including warm tropical climates), the prevalence of hypothermia varies extensively from 8 to 92% across various studies. In developing countries, the typical rates are 32–85% in hospital settings.

Outcomes of Neonatal Hypothermia:

Neonatal hypothermia is an independent risk factor for neonatal mortality across all gestational ages with association showing a dose-response relationship.

Mortality increases by 28% per 1°C decrease in temperature below the normal temperature.

Neonatal hypothermia on admission to neonatal intensive care unit (NICU) has also been consistently associated with intraventricular hemorrhage, bronchopulmonary dysplasia, neonatal sepsis, retinopathy of prematurity, and increased length of hospital stay.

Measurement of Temperature:

Axilla is the recommended site of measurement using a digital thermometer. The thermometer is placed in the baby's armpit and the arm is held close to the body to keep it in place for about 15 seconds or till it beeps.

The temperature is displayed on the thermometer. Temperature can also be recorded continuously by a thermistor attached to a radiant warmer or incubator with the probe attached to the skin over the upper abdomen.

The thermistor senses the skin temperature and displays it on the panel. Both the above methods are acceptable. Rectal measurement is not preferred.

Noninvasive measurements of neonatal temperature using infrared thermometers or infrared thermography are not recommended as they are not yet reliable. Novel bracelet devices placed on newborn's wrists to detect hypothermia are fairly accurate detectors of hypothermia and may be used in appropriate settings.

Mechanism of Heat Production in Newborns:

Nonshivering thermogenesis—occurs by utilizing brown fat in newborns. Thermoreceptors on sensing a low temperature result in elevated sympathetic output and this stimulates the beta-adrenergic receptors in the brown fat increasing cAMP. This results in increased metabolism and increases heat production.

Increased metabolic activity—the brain, heart, and liver produce metabolic energy by oxidative metabolism of glucose, fat, and protein.

Peripheral vasoconstriction—reduces blood flow to the skin and decreases loss of heat.

Mechanisms of Heat Loss:

• Follow the 10 steps of "warm chain" recommended by the WHO.
• Draught free and warm delivery room temperature of 25–28°C.
• Radiant warmer to be prewarmed along with all the linen and clothes/cap before delivery.
• Cap prevents significant heat loss in preterm as well as in term infants. Remove wet towel.
• Baby is placed directly on the mother's abdomen or chest after delivery in both vaginal and cesarean delivery.
• Provide warmth by skin-to-skin contact after drying with a warm and dry linen if baby is doing well.
• Breastfeeding can be started immediately and the baby and the mother are covered with a warm blanket. Delay bathing. No bathing in the hospital.
• Resuscitation, if required, should be done under the radiant warmer and heated humidified gases to be used if oxygen or positive pressure ventilation is required.
• Prewarm medications and intravenous (IV) fluid, if required.
• During surgery, abdominal organ coverage reduces the incidence of hypothermia.

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