Effects of a Heated Anesthesia Breathing Circuit on Body Temperature in Anesthetized Rhesus Macaques (Macaca mulatta)

This study evaluated the effects of using a heated anesthesia breathing circuit in addition to forced-air warming on bodytemperature in anesthetized rhesus macaques as compared with forced-air warming alone. Hypothermia is a common perianestheticand intraoperative complication that can increase the risk of negative outcomes. Body heat is lost through 4 mechanisms during anesthesia: radiation, conduction, convection, and evaporation. Typical warming methods such as forced-air warming devices, conductive heating pads, and heated surgical tables only influence radiative and conductive mechanisms of heatloss. A commercially available heated breathing circuit that delivers gas warmed to 104 °F can easily be integrated into ananesthesia machine. We hypothesized that heating the inspired anesthetic gas to address the evaporative mechanism of heatloss would result in higher body temperature during anesthesia in rhesus macaques. Body temperatures were measured at 5-min intervals in a group of 10 adult male rhesus macaques during 2 anesthetic events: one with a heated anesthesia breathing circuit in addition to forced-air warming, and one with forced-air warming alone. The addition of a heated breathing circuit had a significant positive effect on perianesthetic body temperature, with a faster return to baseline temperature, earlier nadir of initial drop in body temperature, and higher body temperatures during a 2-h anesthetic procedure. Use of a heated anesthesia breathing circuit should be considered as a significant refinement to thermal support during macaque anesthesia, especially for procedures lasting longer than one hour.

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Comparison of Three Intraoperative Patient Warming Systems

Journal of the American Animal Hospital Association ◽

10.5326/jaaha-ms-5650 ◽

2012 ◽

Vol 48 (1) ◽

pp. 18-24 ◽

Cited By ~ 3

Author(s):

Michelle A. Franklin ◽

Mark C. Rochat ◽

Mark E. Payton ◽

Kristyn D. Broaddus ◽

Kenneth E. Bartels

Keyword(s):

Clinical Trial ◽

Body Temperature ◽

Surgical Procedures ◽

Circulating Water ◽

Forced Air Warming ◽

Warming Blanket ◽

Significant Temperature ◽

Forced Air ◽

Warming Devices ◽

Over Time

The purpose of this randomized clinical trial was to compare the efficacy of three patient warming devices (i.e., circulating water blanket, forced-air, and warming panels) used either alone or in combination on patients undergoing surgeries lasting >60 min. In total, 238 dogs were included and divided into either the celiotomy or nonceliotomy group. Dogs in each group were further divided into one of three subgroups. Dogs in subgroup 1 (n=39) were placed on a circulating water blanket with a forced-air warming blanket placed over the trunk. Subgroup 2 dogs (n=40) were placed on a forced-air warming blanket only. Subgroup 3 dogs (n=40) were placed on warming panels. Significant temperature drops occurred from time of induction (38.1°C±0.64°C) to the start of surgical procedures (36.7°C±0.95°C). Although body temperature was maintained once the warming units were started in all groups, there were significant differences in temperatures for the type of surgical procedures (i.e., celiotomies versus nonceliotomies) performed over time except for subgroup 3. The warming panels and forced-air devices were equally effective in preserving body temperature in anesthetized patients.

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2521 Use of forced air warming devices to induce fever-range hyperthermia in critically ill septic patients

Journal of Clinical and Translational Science ◽

10.1017/cts.2018.191 ◽

2018 ◽

Vol 2 (S1) ◽

pp. 50-50

Author(s):

Anne M. Drewry ◽

Enyo A. Ablordeppey ◽

Marin H. Kollef ◽

Richard S. Hotchkiss

Keyword(s):

Heart Rate ◽

Body Temperature ◽

Control Group ◽

Clinical Effects ◽

Intervention Period ◽

Secondary Infections ◽

Forced Air Warming ◽

Severity Scores ◽

Forced Air ◽

Warming Devices

OBJECTIVES/SPECIFIC AIMS: Afebrile septic patients are twice as likely to die and develop nosocomial infections as compared with those with fever; the reason for these differences is unknown. One hypothesis is that elevated temperatures directly boost immunity and inhibit microorganism growth. However, there is little data examining the clinical effects of warming septic patients. The goal of this study was to determine whether warming afebrile septic patients to fever-range hyperthermia with noninvasive forced air warmers is feasible and safe. METHODS/STUDY POPULATION: This is an ongoing randomized trial on afebrile mechanically ventilated patients with severe sepsis. The intervention consisted of 48 hours of external warming with a forced air warming device to a goal core temperature of 1.5°C higher than the lowest recorded temperature within the 24 hours preceding enrollment. Efficacy of the intervention and adverse event data (i.e., increases in heart rate and vasopressor doses) were collected. Clinical outcomes included 28-day mortality and acquisition of secondary infections. RESULTS/ANTICIPATED RESULTS: In total, 18 patients were randomized to the control and warming groups, respectively. Baseline characteristics (including demographics, comorbidities, and illness severity scores) were similar among the 2 groups, except the control group had more males (61% vs. 28%, p=0.04). Median (IQR) body temperature averaged over the 48-hour intervention period was higher in the warming group [38.2 (37.6, 38.6) vs. 37.1 (36.4, 37.4) °C, p<0.001). Patients in the warming group achieved core temperatures above their goal for a median of 37 (IQR 11, 45) hours during the 48-hour intervention period. There were no differences in heart rate or vasopressor dose changes or acquisition of secondary infections between the groups. Eight (44.4%) control patients and 3 (16.7%) warmed patients died by day 28 (p=0.07). DISCUSSION/SIGNIFICANCE OF IMPACT: Externally warming severe septic patients with forced air warming devices effectively raises core body temperature and is safe. Additional research will focus on cellular and immunological changes seen in warmed Versus control patients.

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Burns from Misuse of Forced-Air Warming Devices

Biomedical Safety & Standards ◽

10.1097/00149078-200303010-00017 ◽

2003 ◽

Vol 33 (4) ◽

pp. 31

Keyword(s):

Forced Air Warming ◽

Forced Air ◽

Warming Devices

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Comparison of two forced-air warming devices during foot and ankle surgery: a randomised controlled trial

Journal of Perioperative Practice ◽

10.1177/1750458920927286 ◽

2020 ◽

Vol 30 (11) ◽

pp. 340-344

Author(s):

Jorge Javier Del Vecchio ◽

Lucas Nicolás Chemes ◽

Mauricio Esteban Ghioldi ◽

Eric Daniel Dealbera ◽

Pablo Daniel Morgillo

Keyword(s):

Controlled Trial ◽

Foot And Ankle ◽

Air Heating ◽

Forced Air Warming ◽

Ankle Surgery ◽

Forced Air ◽

Randomised Controlled ◽

Warming Devices ◽

Frequent Problem ◽

Uniform Population

Inadvertent perioperative hypothermia is a frequent problem associated with surgical patients which can have significant consequences during surgery and in the immediate postoperative period. We compared 35 randomised patients using over vs. under body forced air heating. There were no statistically significant differences between some demographic and surgical parameters such as: age, weight, height, body mass index, length of anaesthesia and operation. Statistically significant differences were found between the patient’s admission to the operating room and 30 minutes and the end of the procedure on the under body patients group. This study analyses a uniform population of patients (Foot and Ankle Surgery) previously not studied and supports the use of under body blankets.

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