Temperature Management in Critically ill Patients

Abstract

Temperature control (thermoregulation) is a part of homeostatic mechanism that keeps the organism at optimum operating temperature, as it affects the rate of chemical reactions. In humans, the normal internal temperature varies from 36.5 °C to 37.5 °C, though it varies among individuals. However, no person always has exactly the same temperature at every moment of the day. Temperature cycle regularly up and down through the day, as controlled by the person's circadian rhythm. The body temperature of a healthy person varies during the day by about 0.5 °C with lower temperatures in the morning and higher temperatures in the late afternoon and evening, as the body's needs and activities change. Hyperthermia (temperature >37.5 °C) occurs when the body produces or absorbs more heat than it can dissipate. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to deal effectively with the heat, causing the body temperature to climb uncontrollably. Hyperthermia at or above about 40 °C is a life-threatening medical emergency that requires immediate treatment. Common symptoms include headache, confusion, and fatigue. If sweating has resulted in dehydration, then the affected person may have dry, red skin.