Study of the Prevalence of Postoperative Hypothermia in Adults Undergoing Non-Cardiac Surgery in Spanish Post-Anesthesia Care Units

The prevalence of Hypothermia in Spanish Post-Anesthesia Recovery Units (in Spanish: "Prevalencia de Hipotermia en las Reanimaciones Españolas" PHRES Study) is a prospective, multicenter observational study that will evaluate how often adults develop unintended low body temperature after non-cardiac surgery in post-anesthesia recovery units in Spain. Unintended low body temperature, known as perioperative hypothermia, is a common problem after surgery and may be associated with complications such as shivering, increased bleeding, heart problems, discomfort, and delayed recovery. Although active warming devices and temperature monitoring are available in many Spanish hospitals, their use may vary between centers. The study will include adults undergoing scheduled non-cardiac surgery lasting more than 60 minutes under general, regional, or combined anesthesia. Approximately 1,334 patients from 25-30 Spanish hospitals are expected to participate. Patients will be included consecutively according to predefined eligibility criteria. The study will record information about the patient, the type and duration of surgery and anesthesia, and the measures used to prevent low body temperature before and during surgery, including active warming and temperature monitoring. On arrival in the post-anesthesia recovery unit, the patient's core body temperature will be measured using the same non-invasive temperature monitoring technology in all participating centers. The main objective is to determine the proportion of patients with a core temperature below 36°C at the time of admission to the recovery unit. The study will also investigate factors associated with postoperative hypothermia and record complications occurring shortly after surgery, such as shivering, hemodynamic instability, new-onset arrhythmias, significant bleeding, and the need for blood transfusion. This is an observational study. The study will not determine or change how patients are warmed or how their temperature is monitored during surgery. These decisions will remain the responsibility of the treating anesthesia team according to local clinical practice. The additional temperature measurement performed for the study is non-invasive and does not involve any significant additional risk to participants.