Which of the following is NOT an effective means of preventing hypothermia in a 10-month-old undergoing surgery?

Which of the following is NOT an effective means of preventing hypothermia in a 10-month-old undergoing surgery?

• A. Placement of an infrared heater over the operating table and prewarming the OR
• B. Covering the OR table with a heating blanket
• C. Wrapping the extremities with sheet wadding and covering the head with a cloth cap
• D. Ventilating the patient with a Mapleson D circuit at low gas flows (e.g., 50 mL/kg/min)

Answer: (D)

Maintaining normothermia in a small infant during surgery relies on reducing heat loss and actively warming the patient and inspired gases. Infants lose heat rapidly through their large surface area relative to body mass, so external warming and insulation are key strategies: radiant or infrared heating and prewarming the operating room help reduce radiant and environmental heat loss; a heating blanket beneath the table provides conductive warmth; wrapping the extremities and covering the head minimize exposed surface area and convective heat loss. Ventilating with a Mapleson D circuit at very low fresh gas flows, on the other hand, does not inherently warm or humidify the inspired gas. Without warmed, humidified gases, airway heat loss can actually persist or increase, and the ventilation setup itself does not address the main routes of heat loss. Therefore, this approach is not an effective means of preventing hypothermia.

Maintaining normothermia in a small infant during surgery relies on reducing heat loss and actively warming the patient and inspired gases. Infants lose heat rapidly through their large surface area relative to body mass, so external warming and insulation are key strategies: radiant or infrared heating and prewarming the operating room help reduce radiant and environmental heat loss; a heating blanket beneath the table provides conductive warmth; wrapping the extremities and covering the head minimize exposed surface area and convective heat loss.

Ventilating with a Mapleson D circuit at very low fresh gas flows, on the other hand, does not inherently warm or humidify the inspired gas. Without warmed, humidified gases, airway heat loss can actually persist or increase, and the ventilation setup itself does not address the main routes of heat loss. Therefore, this approach is not an effective means of preventing hypothermia.