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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Aged, Aortic Aneurysm, Abdominal, Female, Hot Temperature, Humans, Hypothermia, Male, Middle Aged, Prospective Studies.
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Does the use of countercurrent heat exchangers diminish accidental hypothermia during abdominal aortic aneurysm surgery? Context: Perioperative hypothermia is common and likely contributes to morbidity, but the efficacy of prophylactic fluid warning has hardly been analyzed systematically. We tested the hypothesis that the use of an infusion/blood warmer, based on the principle of countercurrent heat exchange, reduces incidence and degree of severe hypothermia following aortic surgery. In a prospective randomized investigation of patients (n = 50) undergoing elective abdominal aortic aneurysm surgery, all fluids/blood products (approx. 3500 ml) administered intraoperatively were infused either (n = 25) via countercurrent-like heat exchangers (Hotline Level 1 Technologies Inc.) or without (n = 25) taking special precautions (infusions stored at 21 degrees C, blood products heated to 37 degrees C in a water bath). Anaesthesia was standardized using a thiopentone, fentanyl, vecuronium induction sequence, and maintained by isoflurane in N2O/O2. The perioperative decrease of oesophageal temperature (-0.35 degree C +/- 0.4) in the group managed with heat exchangers was significantly smaller (P < 0.0001) than in the control group (-1.5 degrees C +/- 0.54), and oesophageal temperature at the end of surgery was considerably higher (35.1 degrees C +/- 0.45 vs. 34.2 degrees C +/- 0.7; P < 0.0001). Furthermore, while postoperative hypothermia below 34.5 degrees C was observed in 16 patients (incidence: 64%) of the control group, it occurred in only 2 patients (incidence: 8%) managed with heat exchangers (P < 0.001).
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The efficacy of fluid/blood warmers has hitherto only been evaluated in bench tests. Our results demonstrate that the use of heat exchangers alone, while not completely preventing hypothermia, markedly reduces the incidence of severe perioperative hypothermia, and lessens its degree during abdominal aortic aneurysm surgery. Final Decision: yes