Table 4 Warming methods

Warming blanket

Bair Hugger 750, 505 (Arizant Healthcare Inc., Eden Prairie, MN, USA)

Air delivered to variety of blankets (upper, lower, full, torso, surgical access, pediatric, cardiac) at three settings: high (43 °C), medium (38 °C), low (32 °C)

Convection

Equator (Smiths Medical ASD, Rockland, MA, USA)

Air delivered to adult and pediatric blankets. Settings: high (44 °C), medium (40 °C), low (36 °C)

Convection

Thermacare TC3000 series (Gaymar Industries, Inc., Orchard Park, NY, USA)

Air delivered to adult and pediatric quilts: low (32 °C), medium (38 °C), high (43 °C), maximum (46 °C)

Convection

WarmTouch 5200 (Nellcor, Pleasanton, CA, USA)

Air delivered to adult and pediatric blankets: high (42–46 °C), medium (36–40 °C), and low (30–34 °C)

Convection

Circulating water garment

Medi-Therm III (Gaymar Industries, Inc.)

Circulates water from the control unit to polymer hyper/hypothermia blankets. Manual settings: 4–42 °C; automatic: 30–39 °C

Conduction

Blanketrol II Hyper–Hypothermia Water System (Cincinnati SubZero Products, Cincinnati, OH, USA)

Circulates water from the control unit to specialized blankets (adult and pediatric). Temperature range, 4–42 °C

Conduction

Heated air mattress

Polar Air (Augustine Medical, Inc., Eden Prairie, MN, USA)

Has not been shown to be effective [73] because only a limited amount of body surface area comes into contact with the mattress. Trauma patients may be vulnerable to burn injury

Conduction

Hot packs

Hot Cycle 1 (Sign Manufacturing Corporation, Fairfield, CA, USA)

Temperature at approximately 54.5 °C. Mean increase in temperature of 1.4 °C compared with a mean decrease of 0.3–0.6 °C in controls. Further research is necessary [64]

Conduction

Humidified gases

Heated Anesthesia Circuit (ANAPOD Westmed, Inc., Tucson, AZ, USA)

Delivery of warm, humidified gas can increase core temperature by 0.5–0.65 °C/h in injured patients [74]

Evaporation

Fluid warmer

General

Warmed fluids were found to increase temperature to 36.8 °C compared with 35.5 °C in nonwarmed patients [75]

Conduction

Level 1 System H-1200, H-1000, H-1025, H-525, H-500, H-275, H-250 (Smiths Medical ASD, Rockland, MA, USA)

Aluminum heat exchanger with countercurrent 42 °C circulating water bath. Air detector/clamp

Conduction

Hotline (Smiths Medical ASD)

Water bath heat exchange. Surrounds patient line with layer of 42 °C circulating fluid

Conduction

FW600 Medi Temp III (Gaymar Industries, Inc.)

Dry heat exchange. Plastic disposable with aluminum heating plates (set point, 41 °C)

Conduction

Thermal Angel TA-200 (Estill Medical Technologies, Dallas, TX, USA)

Battery-powered, portable in-line warmer. Outlet temperature, 38 ± 3 °C at flow rate 2–150 ml/min

Conduction

Warmflo FW538 (Nellcor)

Dry heat exchange. Single-use metal cassette. Maximum flow rate, 500 ml/min

Conduction

Other

AV-300: CAVR – continuous

Rapid core rewarming. Circulates colder blood of patient through Level 1 heat exchanger and returns it to patient at Smiths Medical ASD

Conduction

CairCooler (Pentatherm Ltd, Wakefield, UK)

Forced-air cooling system. Connects to forced-air blanket to deliver 10 °C air

Conduction

Arctic Sun 2000 (Medivance, Louisville, CO, USA)

Circulating water temperature is controlled between 4 °C (39.2 °F) and 42 °C (107.6 °F) to achieve a preset target patient temperature

Conduction

Lavage

The specific heat and rate of heat transfer in water is 32-fold greater than air, which permits effective hypothermia management [76]. The rate of rewarming is 1–3 °C per hour if done continuously

Conduction

CPB

Hemodialysis (rate of rewarming is 2–3 °C/h), CPB using a heat exchanger (8–15 °C/h), and extracorporeal venovenous rewarming are other options for rewarming [77–79]. CPB is therefore the only technique that can also correct the hemodynamic stability of the patient and provides the greatest heat transfer

Conduction