Managing perioperative hypothermia

Abstract

surrounds this thermal core. The peripheral temperature ranges between 31° and 35°C, whereas skin temperature is generally 28° to 32°C [2,4]. The peripheral shell protects the thermal core by either absorbing heat from or releasing heat to the environment. The range of core temperatures that are tolerated without triggering a thermoregulatory response is known as the interthreshold range. This range is normally 0.2°C. Within this range, no autonomic responses to cold or warmth occur. Below the hypothermia threshold, vasoconstriction is triggered, followed by shivering as the temperature decreases further. Peripheral vasoconstriction takes place in arteriovenous shunts located primarily in the fingers and toes. These are controlled by centrally mediated α 1 -adrenergic receptors, but the vasoconstriction triggered by local hypothermia is augmented by α 2 -adrenergic receptors [3]. Shivering is an involuntary muscular activity that increases metabolic rate and oxygen consumption. The response to body temperatures above the hyperthermia threshold is perspiration.Reliable sites for monitoring the core temperature include the tympanic membrane, the nasopharynx, the distal esophagus, the rectum, and the pulmonary arteries. These reflect core temperature even during rapid cooling or rewarming [5]. The tympanic membrane temperature reflects that of the blood supplying the hypothalamus [6]. Measurement of temperature in the ear canal avoids the risk of tympanic membrane perforation. Esophageal probes are a popular means of temperature monitoring, and the results correlate well with tympanic membrane temperature [7]. It is important to note that the inspired air temperature affects the esophageal temperature and that the esophagus has a large temperature gradient along its length [8]. For investigative purposes, the esophageal probe is placed 12 to 16 cm distal to the best heart-lung sounds [9], but for clinical use it should be placed at the point of maximal heart sounds. Rectal probes have slow response rates and may give inaccurate readings.

A retrospective analysis on the relationship between intraoperative hypothermia and postoperative ileus after laparoscopic colorectal surgery

“…A mild degree of intraoperative hypothermia, defined as a core temperature of 34.0–36°C, is an important and preventable cause of surgical complications and morbidity. This state has negative effects on bleeding and transfusion requirements, shivering, discomfort, postanesthetic recovery, morbid cardiac events, surgical wound infection, and duration of hospitalization [ 1 ]. Thus, intraoperative maintenance of normothermia is strongly recommended by several versions of the enhanced recovery after surgery (ERAS) guidelines as one of the major elements of perioperative care in colorectal surgery [ 2 , 3 ].…”

Klinische Möglichkeiten zur Steuerung der Körpertemperatur

“…Verminderung der Wärmabgabe durch passive Maßnahmen, wie Isolation und Verminderung des Temperaturgradien ten zwischen Patient und Umgebung, so wie aktive Maßnahmen, wie Wärmezu fuhr, sind im Rahmen eines modernen Temperaturmanagements maßgeblich, um die Aufrechterhaltung perioperativer Normothermie zu gewährleisten [22].…”

Severe burn injury associated with misuse of forced-air warming device

“…Forced-air warming is one of the most frequently used methods of patient warming in the operating room [1]. This device comprises an electrical heater unit, a hose, and a blanket.…”