The use of countercurrent heat exchangers diminishes accidental hypothermia during abdominal aortic aneurysm surgery

Abstract

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.

The care of patients with an abdominal aortic aneurysm: The Society for Vascular Surgery practice guidelines

“…399 Forced air warming blankets have been shown to be beneficial 400 when compared with circulating water mattresses alone. 399 Warmed inhaled gasses 401 and infused liquids 402 have also been shown to be of benefit. The benefit of forced air-warming blankets applied to the lower extremities, as opposed to the upper trunk, during prolonged aortic clamping is unknown.…”

An analytical study of heat transfer in a finite tissue region with two blood vessels and general Dirichlet boundary conditions

“…Due to the postulated importance of counter-current blood circulation in determining the tissue temperature distribution [1][2][3][4][5][6][7], the effect of the counter-current blood circulation on the tissue temperature distributions has been extensively studied for bio-heat transfer 0017 Nomenclature A t area of the tissue, pðr 2 tw À r 2 vw1 À r 2 vw2 Þ a vi distance between the centers of the tissue and the ith vessel, i = 1, 2 (m) f vwi temperature at vessel wall i = 1, 2 (K) f tw temperature at the tissue boundary (K) g 000 uniform source term in the tissue per unit volume (W/m 3 ) k conductivity of the tissue (W/(m K)) q vw1-vw2 heat transfer from vessel wall one to vessel wall two (W/m) q tw-vw1 heat transfer from tissue to vessel wall one (W/m) q tw-vw2 heat transfer from tissue to vessel wall two (W/m) q total,vw1 total heat transfer to vessel wall one (W/m) q total,vw2 total heat transfer to vessel wall two (W/m) r radial distance (m) r i perimeter of vessel ÔiÕ from the center of outer tissue cylinder fða vi þ r vwi cos h i Þ 2 þ ðr vwi sin h i Þ 2 g 1 2 , i = 1, 2 (m) r vwi radius of the ith vessel, i = 1, 2 (m) r tw outer radius of the tissue boundary (m) t temperature of the tissue t avg area averaged tissue matrix temperature, 1 At R At t dA, (K) t vwi, 1 mean temperature at the ith vessel wall, i = 1, 2 (K) t vwi, 2 fluctuation in temperature at the ith vessel wall, i = 1, 2 (K) t tw, 1 mean temperature at the tissue boundary (K) t tw, 2 fluctuation in temperature at the tissue boundary (K) x, y Cartesian coordinates in the original problem (m) x i , y i Cartesian coordinates in sub-problem i, x 1 = x, y 1 = y, x 2 ¼ x 1 cosð/ 1 Þ þ y 1 sinð/ 1 Þ, y 2 ¼ y 1 cosð/ 1 Þ À x 1 sinð/ 1 Þ; i ¼ 1; 2 ðmÞ…”

Heating capabilities of the Hotline® and Autoline® at low flow rates

“…Fluid warming devices have made a major contribution in maintaining patients in a normothermic state during surgery (1). This is of great importance since perioperative hypothermia has been shown to be associated with increased oxygen consumption, blood loss, and a higher incidence of surgical‐wound infections (2–4).…”