Measuring temperature including heat and thermodynamics

Many items of equipment used in anaesthesia and intensive care rely on the principles of thermodynamics for their operation. Heat loss from the human body may result in perioperative hypothermia and increased morbidity. It is therefore essential to have a sound understanding of the underlying physical principles. This article outlines thermodynamic concepts which are relevant to clinical practice and includes: heat capacity and latent heat; thermal effects on solids, liquids, gases and solutions; mechanisms of heat transfer; and techniques of temperature measurement.