A circulating nurse provides care in a surgical department that has multiple surgeries scheduled for the day. The nurse should know to monitor which patient most closely during the intraoperative period because of the increased risk for hypothermia?

Choice A reason: Elderly patients are at the highest risk for perioperative hypothermia due to a lower basal metabolic rate, reduced subcutaneous fat, and impaired thermoregulatory mechanisms. A low body mass index further exacerbates this risk because there is less insulation to prevent radiant heat loss in the cold operating room environment, especially under the influence of vasodilating anesthetic agents. Choice B reason: While trauma patients are at risk for the "lethal triad" (hypothermia, acidosis, and coagulopathy), a 17-year-old generally possesses robust thermoregulatory responses and a higher metabolic rate compared to an elderly patient. Unless the trauma involves massive hemorrhage or prolonged exposure before arrival, the age-related physiological decline makes the 74-year-old a more significant thermoregulatory concern. Choice C reason: An abdominal hysterectomy involves exposing the peritoneal cavity, which increases evaporative and radiant heat loss. However, a 45-year-old woman typically has better physiological reserves and more subcutaneous adipose tissue than a frail 74-year-old with a low BMI. The elderly patient's inability to effectively shiver or vasoconstrict makes them the higher priority for thermal monitoring. Choice D reason: Craniofacial surgery in a 13-year-old involves significant exposure, but pediatric patients of this age are beginning to have thermoregulatory responses similar to adults. While all surgical patients require monitoring, the combination of advanced age and low BMI creates a profound physiological inability to maintain core temperature, necessitating the most vigilant intraoperative thermal management.