Clinical practice guideline. Unintentional perioperative hypothermia. / Guía de práctica clínica de hipotermia perioperatoria no intencionada.

The importance of the safety of our patients in the surgical theatre, has driven many projects. The majority of them aimed at better control and clinical performance; mainly of the variables that intervene or modulate the results of surgical procedures, and have a direct relationship with them. The Spanish Society of Anesthesiology, Critical Care and Therapeutic Pain (SEDAR), maintains a constant concern for a variable that clearly determines the outcomes of our clinical processes, "unintentional hypothermia" that develops in all patients undergoing an anesthetic or surgical procedure. SEDAR has promoted, in collaboration with other scientific Societies and patient Associations, the elaboration of this clinical practice guideline, which aims to answer clinical questions not yet resolved and for which, up to now, there are no documents based in the best scientific evidence available. With GRADE methodology and technical assistance from the Ibero-American Cochrane Collaboration office, this clinical practice guideline presents three recommendations (weak in favor) for active heating methods for the prevention of hypothermia (skin, fluid or gas); three for the prioritization of strategies for the prevention of hypothermia (too weak in favor and one strongly in favor); two of preheating strategies prior to anesthetic induction (both weak in favor); and two for research.

[Non-therapeutic intraoperative hypothermia: prevention and treatment (part II)]. / Hipotermia intraoperatoria no terapéutica: prevención y tratamiento (parte II).

General and regional anesthesia alter the physiological mechanisms of thermoregulation, and unintentional intraoperative hypothermia develops during most surgical procedures that last more than 1 hour. Monitoring of central temperatures among other vital signs is advisable in such interventions in order to detect temperature changes and check the efficacy of measures to prevent or treat hypothermia. Passive insulation reduces heat loss through the skin but most patients require active warming to maintain a normal temperature. Various skin surface warming systems prevent hypothermia from developing and provide effective warming. The most often used are forced-air or warm water circulation devices. When large volumes of fluids must be infused intravenously, they must be warmed to body temperature to avoid heat loss.

[Non-therapeutic intraoperative hypothermia: causes, complications, prevention, and treatment (part I)]. / Hipotermia intraoperatoria no terapéutica: causas, complicaciones, prevención y tratamiento (I parte).

During the first hour of general anesthesia, a patient's body temperature can decrease between 1 and 1.5 degrees C; regional anesthesia also induces central hypothermia. Intraoperative hypothermia interferes with immunological function, particularly with the oxidative capacity of neutrophils. Cutaneous vasoconstriction occurs and blood flow is reduced in tissues subject to surgery. Oxygen transport is also reduced, increasing the risk of postoperative infection. Decreased platelet activity favors blood loss. Hypothermia increases the likelihood of shivering, and with enhanced central nervous system activation, there is increased cardiovascular morbidity. Currently, these effects can be attenuated or even avoided by applying various warming methods available. The efficacy and mechanisms of action of such methods are described in the second part of this review of the literature.