Impact of a Global Warming Strategy of the Patient on the Prevalence of Hypothermia in the Recovering Room

Hypothermia is defined as a core temperature below 36°C. It is classified by severity stage. A temperature below 36°C is mild hypothermia, below 35°C moderate hypothermia and below 34°C severe hypothermia.

The impact of hypothermia on the body is related to decreased metabolic and immune activities. The vasoconstriction induced by hypothermia implies a decrease in vascularization of the organs that can cause tissue damage.

These effects explain the role of hypothermia in the pathophysiology of certain perioperative and postoperative complications in the longer term.

Intraoperative hypothermia is responsible for the increase of:

• 4 times the risk of Surgical Site Infection,
• twice the risk of cardiovascular morbidity, associated with increased mortality,
• 33% of transfusion need,
• 1.5 times the need for continued mechanical ventilation,
• 3 times the duration of recovering room,
• twice the hospital stay. This is why hypothermia is responsible for excess perioperative mortality.

According to a 2019 study (Alfonsi P, Bekka S, Aegerter P, SFAR Research Network investigators. Prevalence of hypothermia on admission to recovery room remains high despite a large use of forced-air warming devices: Findings of a non-randomized observational multicenter and pragmatic study on perioperative hypothermia prevalence in France), the prevalence of hypothermia increases from 16.2% of patients before anesthetic induction to 53.5% of patients admitted to the Recovering room. At the end of Recovering room, 33.2% of patients were hypothermic. Among these patients, 15.2% became hypothermic during the recovering room stay.

The risk factors for perioperative hypothermia are multiple:

Patient-related factors: low body mass index; undernutrition; ASA score > 1; pre-existing conditions altering thermoregulation (ex: diabetes with polyneuropathy, hypothyroidism, consumption of sedative or psychoactive drugs); pre-existing hypothermia at surgery.

Factors related to anesthesia techniques: duration of anesthesia > 2 hours; combined general and neuro-axial anesthesia; administration of large volumes of intravenous solutes or transfusion of non-rewarmed globular units.

Factors related to surgery: type, extent and duration of surgery witch use of large amounts of unheated irrigation fluid.

Inclusion criteria

• Patient undergoing laparoscopic visceral surgery under general anesthesia with transition to recovering room

Exclusion criteria

• Patient undergoing urgent surgery.
• Presence of pre-existing infection (temperature higher than 38°C when receiving the patient in the hospital ward.
• Patient with predetermined length of stay in recovering room.