Atelectasis as a collapse of lung tissue, atelectasis is not synonymous with a pneumothorax, which is a more specific condition that features atelectasis. Acute atelectasis may occur as a post-operative complication or as a result of surfactant deficiency. In premature neonates, this leads to infant respiratory distress syndrome. The term uses combining forms of "atel-" + "ectasis", from , "incomplete" + ἔκτασις, "extension". May have no signs and symptoms or they may include: It is a common misconception that atelectasis causes fever. A study of 100 post-op patients followed with serial chest X-rays and temperature measurements showed that the incidence of
Human body temperature There are various types of medical thermometers, as well as sites used for measurement, including: Temperature control (thermoregulation) is part of a homeostatic mechanism that keeps the organism at optimum operating temperature, as the temperature affects the rate of chemical reactions. In humans, the average internal temperature is , though it varies among individuals. However, no person always has exactly the same temperature at every moment of the day. Temperatures cycle regularly up and down through the day, as controlled by the person's circadian rhythm. The lowest temperature occurs about two hours before the person normally wakes up. Additionally, temperatures