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1.  The Bair Hugger patient warming system in prolonged vascular surgery: an infection risk? 
Critical Care  2003;7(3):R13-R16.
Use of the Bair Hugger forced-air patient warming system during prolonged abdominal vascular surgery may lead to increased bacterial contamination of the surgical field by mobilization of the patient's skin flora.
This possibility was studied by analyzing bacterial content in air and wound specimens collected during surgery in 16 patients undergoing abdominal vascular prosthetic graft insertion procedure, using the Bair Hugger patient warming system. The bacterial colony counts from the beginning and the end of surgery were compared, and the data analyzed using the Wilcoxon matched pairs test.
The results showed not only that there was no increase in bacterial counts at the study sites, but also that there was a decrease (P < 0.01) in air bacterial content around the patient and in the operating theatre after prolonged use of the patient warmer. No wound or graft infections occurred.
The use of this warming system does not lead to increased bacterial contamination of the operating theatre atmosphere, and it is unlikely to affect the surgical field adversely.
PMCID: PMC270670  PMID: 12793885
air microbiology; human; intraoperative care; operating rooms; surgical wound infection
2.  The effect of heated breathing circuit on body temperature and humidity of anesthetic gas in major burns 
Cold and dry gas mixtures during general anesthesia cause the impairment of cilliary function and hypothermia. Hypothermia and pulmonary complications are critical for the patients with major burn. We examined the effect of heated breathing circuit (HBC) about temperature and humidity with major burned patients.
Sixty patients with major burn over total body surface area 25% scheduled for escharectomy and skin graft were enrolled. We randomly assigned patients to receiving HBC (HBC group) or conventional breathing circuit (control group) during general anesthesia. The esophageal temperature of the patients and the temperature and the absolute humidity of the circuit were recorded every 15 min after endotracheal intubation up to 180 min.
There was no significant difference of the core temperature between two groups during anesthesia. The relative humidity of HBC group was significantly greater compared to control group (98% vs. 48%, P < 0.01). In both groups, all measured temperatures were significantly lower than that after intubation.
The use of HBC helped maintain airway humidity, however it did not have the effect to minimize a body temperature drop in major burns.
PMCID: PMC3558651  PMID: 23372879
Anesthesia; Closed circuit; General anesthesia; Humidity; Hypothermia
3.  Core temperatures during major abdominal surgery in patients warmed with new circulating-water garment, forced-air warming, or carbon-fiber resistive-heating system 
Journal of Anesthesia  2011;26(2):168-173.
It has been reported that recently developed circulating-water garments transfer more heat than a forced-air warming system. The authors evaluated the hypothesis that circulating-water leg wraps combined with a water mattress better maintain intraoperative core temperature ≥36°C than either forced-air warming or carbon-fiber resistive heating during major abdominal surgery.
Thirty-six patients undergoing open abdominal surgery were randomly assigned to warming with: (1) circulating-water leg wraps combined with a full-length circulating-water mattress set at 42°C, (2) a lower-body forced-air cover set on high (≈43°C), and (3) a carbon-fiber resistive-heating cover set at 42°C. Patients were anesthetized with general anesthesia combined with continuous epidural analgesia. The primary outcome was intraoperative tympanic-membrane temperature ≥36°C.
In the 2 h after anesthesia induction, core temperature decreased 1.0 ± 0.5°C in the forced-air group, 0.9 ± 0.2°C in the carbon-fiber group, and 0.4 ± 0.4°C in the circulating-water leg wraps and mattress group (P < 0.05 vs. forced-air and carbon-fiber heating). At the end of surgery, core temperature was 0.2 ± 0.7°C above preoperative values in the circulating-water group but remained 0.6 ± 0.9°C less in the forced-air and 0.6 ± 0.4°C less in the carbon-fiber groups (P < 0.05 vs. carbon fiber).
The combination of circulating-water leg wraps and a mattress better maintain intraoperative core temperature than did forced-air and carbon-fiber warming systems.
PMCID: PMC3328673  PMID: 22189652
Temperature; Hypothermia; Circulating-water garment; Carbon fiber; Forced air
4.  Critical dependence of acetate thermal mattress on gel activation temperature 
Sodium acetate gel mattresses provide an active method of warming patients through release of latent heat of crystallisation. They can be used as an adjunct to incubator care or as an exclusive heat source.
To determine activation temperatures of the Transwarmer mattress needed to achieve plateau temperatures of 38–42°C.
Design and setting
In vitro testing of mattress temperature.
Methods and outcome measures
Transwarmer mattresses were activated at initial temperatures ranging from 5 to 40°C. Mattress temperature was recorded up to 4 h to determine peak and plateau temperatures. Peak and plateau temperatures achieved by the mattress were related to the initial starting temperature.
The starting temperature of the mattress was strongly correlated with peak and plateau temperature (r = 0.99, p<0.001). To achieve the target temperature of 38–42°C, the Transwarmer mattress requires activation between 19.2°C and 28.3°C. A temperature of 37°C could be generated by activation at 17°C.
Safe use of this device is critically dependent on gel temperature at the point of activation. To ensure warming of a hypothermic neonatal patient without running any risk of burns, the mattress should be activated with a gel temperature between 19°C and 28°C.
PMCID: PMC2675300  PMID: 16877478
5.  Absence of Exertional Hyperthermia in a 17 Year Old with Severe Burns 
An important safety concern when exercising burned patients is the potential for an excessive increase in core body temperature (hyperthermia = body core temperature > 39°C) during exercise.
We examined the thermoregulatory response to exercise in the heat (31°C, relative humidity 40%) in a 17 year old with a 99% total body surface area burn. A 30 minute exercise test was performed at an intensity of 75% of his peak aerobic capacity. Intestinal temperature was assessed via telemetry with an ingestible capsule. Intestinal temperature was measured pre-exercise, during, and post-exercise.
The patient completed 12 minutes of the 30 minute exercise test. Starting core temperature was 36.98 °C and increased 0.69 °C during exercise. After excercise, intestinal temperature continued to increase, but no hyperthermia was noted.
It has been reported that burned children can safely exercise at room temperature, however, the response in the heat is unknown. This patient did not develop exertional hyperthermia, which we propose is due to his low fitness level and heat intolerance. However, the potential for hyperthermia would be increased if he were forced to maintain a high relative workload in the heat. We propose that severely burned individuals should be able to safely participate in physical activities. However, the decision to stop exercising should be accepted to avoid development of exertional hyperthermia.
PMCID: PMC3924868  PMID: 19506510
thermoregulation; hyperthermia; burns; exercise
6.  Rewarming preterm infants on a heated, water filled mattress. 
Archives of Disease in Childhood  1989;64(5):687-692.
Sixty low birthweight infants (1000-2000 g) admitted to a neonatal care unit in Turkey were studied. Those not requiring intensive care were randomly assigned for treatment either in a cot on a heated, water filled mattress kept at 37 degrees C (n = 28) or in air heated incubators with a mean air temperature of 35 degrees C (n = 32). On admission 53 (88.3%) of the infants had body temperatures between 30 degrees and 36 degrees C. There was good correlation between axillary and rectal temperatures in the infants while they were hypothermic. Normal temperatures were achieved within the first day and remained within this range during the subsequent days after admission in all the infants treated on the heated, water filled mattress, whereas they were not achieved until three days later in the incubator group. The neonatal mortality among those treated on the heated, water filled mattress was 21%, and among those treated in the incubator 34%. The heated, water filled mattress provides a good alternative to skin to skin contact with the mother, and to the use of a complex and expensive incubator for rapidly attaining and maintaining normal temperatures in the low birthweight newborn.
PMCID: PMC1792015  PMID: 2730122
7.  Burns From Hot Wheat Bags: A Public Safety Issue 
Eplasty  2011;11:e36.
Introduction: Wheat bags are therapeutic devices that are heated in microwaves and commonly used to provide relief from muscle and joint pain. The Royal Adelaide Hospital Burns Unit has observed a number of patients with significant burn injuries resulting from their use. Despite their dangers, the products come with limited safety information. Methods: Data were collected from the Burns Unit database for all patients admitted with burns due to hot wheat bags from 2004 to 2009. This was analyzed to determine the severity of the burn injury and identify any predisposing factors. An experimental study was performed to measure the temperature of wheat bags when heated to determine their potential for causing thermal injury. Results: 11 patients were admitted with burns due to hot wheat bags. The median age was 52 years and the mean total body surface area was 1.1%. All burns were either deep dermal (45.5%) or full thickness (54.5%). Ten patients required operative management. Predisposing factors (eg, neuropathy) to thermal injury were identified in 7 patients. The experimental study showed that hot wheat bags reached temperatures of 57.3°C (135.1°F) when heated according to instructions, 63.3°C (145.9°F) in a 1000 W microwave and 69.6°C (157.3°F) on reheating. Conclusions: Hot wheat bags cause serious burn injury. When heated improperly, they can reach temperatures high enough to cause epidermal necrosis in a short period of time. Patients with impaired temperature sensation are particularly at risk. There should be greater public awareness of the dangers of wheat bag use and more specific safety warnings on the products.
PMCID: PMC3160380  PMID: 21915357
8.  Rewarming of healthy volunteers after induced mild hypothermia: a healthy volunteer study 
Emergency Medicine Journal : EMJ  2005;22(3):182-184.
Objectives: The study compares the efficacy of two active and one passive warming interventions in healthy volunteers with induced mild hypothermia.
Methods: Eight volunteers were studied in a random order crossover design. Each volunteer was studied during re-warming from a core temperature of 35°C with each of: a radiant warmer (Fisher & Paykel); a forced air warmer (Augustine Medical), and a polyester filled blanket, to re-warm.
Results: No significant differences in re-warming rates were observed between the three warming devices. It was found that the subject's endogenous heat production was the major contributor to the re-warming of these volunteers. Metabolic rates of over 350 W were seen during the study.
Conclusions: For patients with mild hypothermia and in whom shivering is not contraindicated our data would indicate that the rate of re-warming would be little different whether a blanket or one of the two active devices were used. In the field, this may provide the caregiver a useful choice.
PMCID: PMC1726709  PMID: 15735265
9.  Objective Assessments of Temperature Maintenance Using In Vitro Culture Techniques 
Purpose: To assess the ability of various facets of embryo culture (microscope stage warmers, volumes of culture media, culture vessel lids, and type of culture incubator) to maintain a constant temperature in vitro.
Methods: Ability to maintain 37.0°C in the microenvironment of gametes was recorded by digital thermocouple in the chosen facets of in vitro culture.
Results: Stage warmers are highly variable in their ability to maintain the set temperature (range 33.8°C–37.0°C after 60 s). Temperature loss in culture media is both volume and vessel dependent, and the direct heat transfer culture incubator (MINC) has superior temperature maintenance compared with a large volume air convection incubator (FORMA), where temperature regain from 35.0°C to 37.0°C took 5.5 min compared to >20 min.
Conclusions: There are large measurable differences in the ability to maintain set temperature that depend on the stage warmer used, volume of media, use of vessel lids, and the type of incubator chosen for IVF culture.
PMCID: PMC3455576  PMID: 12182443
Culture volume; incubators; oil overlay; stage warmers; temperature
10.  Accumulation and transport of microbial-size particles in a pressure protected model burn unit: CFD simulations and experimental evidence 
Controlling airborne contamination is of major importance in burn units because of the high susceptibility of burned patients to infections and the unique environmental conditions that can accentuate the infection risk. In particular the required elevated temperatures in the patient room can create thermal convection flows which can transport airborne contaminates throughout the unit. In order to estimate this risk and optimize the design of an intensive care room intended to host severely burned patients, we have relied on a computational fluid dynamic methodology (CFD).
The study was carried out in 4 steps: i) patient room design, ii) CFD simulations of patient room design to model air flows throughout the patient room, adjacent anterooms and the corridor, iii) construction of a prototype room and subsequent experimental studies to characterize its performance iv) qualitative comparison of the tendencies between CFD prediction and experimental results. The Electricité De France (EDF) open-source software Code_Saturne® ( was used and CFD simulations were conducted with an hexahedral mesh containing about 300 000 computational cells. The computational domain included the treatment room and two anterooms including equipment, staff and patient. Experiments with inert aerosol particles followed by time-resolved particle counting were conducted in the prototype room for comparison with the CFD observations.
We found that thermal convection can create contaminated zones near the ceiling of the room, which can subsequently lead to contaminate transfer in adjacent rooms. Experimental confirmation of these phenomena agreed well with CFD predictions and showed that particles greater than one micron (i.e. bacterial or fungal spore sizes) can be influenced by these thermally induced flows. When the temperature difference between rooms was 7°C, a significant contamination transfer was observed to enter into the positive pressure room when the access door was opened, while 2°C had little effect. Based on these findings the constructed burn unit was outfitted with supplemental air exhaust ducts over the doors to compensate for the thermal convective flows.
CFD simulations proved to be a particularly useful tool for the design and optimization of a burn unit treatment room. Our results, which have been confirmed qualitatively by experimental investigation, stressed that airborne transfer of microbial size particles via thermal convection flows are able to bypass the protective overpressure in the patient room, which can represent a potential risk of cross contamination between rooms in protected environments.
PMCID: PMC3056797  PMID: 21371304
11.  Thermal protective uniforms and hoods: impact of design modifications and water content on burn prevention in New York City firefighters: laboratory and field results 
Injury Prevention  2001;7(Suppl 1):i43-i49.
Objectives—To determine (1) the effectiveness of hoods in reducing head burns, (2) the impact of clothes worn under the protective outer uniform (modern = long sleeve shirt and long pants; modified modern = short sleeve T-shirt and short pants) on burns, and (3) whether water content (dry, damp or saturated) affects the level of thermal protection.
Setting—Fire Department of the City of New York (FDNY).
Methods—Laboratory tests (fully dressed manikin) evaluated the different uniform and water conditions when exposed to an average 24 cal/cm2 heat flux, approximately 2250°F air temperature. FDNY field results compared (1) head burns during winters wearing the hood to winters without hood and (2) upper and lower extremity burns during summers wearing traditional, modern, and modified modern uniforms.
Results—Laboratory tests showed that thermal protection was: (1) dramatically improved by the hood with protection increasing as water content increased and (2) not significantly different between modern and modified modern uniforms, regardless of water content. FDNY field results confirmed these tests showing (1) significant decreases in neck burns (by 54%), ear burns (by 60%), and head burn totals (by 46%) wearing the hood and (2) no significant differences in upper or lower extremity burns wearing modern compared with modified modern uniforms.
Conclusions—Based on combined laboratory and field results, we strongly recommend the use of modern thermal protective hoods and the modified modern uniform.
PMCID: PMC1765413  PMID: 11565971
12.  Investigating the role of capacitive coupling between the operating table and the return electrode of an electrosurgery unit in the modification of the current density distribution within the patients’ body 
Electrosurgery units are widely employed in modern surgery. Advances in technology have enhanced the safety of these devices, nevertheless, accidental burns are still regularly reported. This study focuses on possible causes of sacral burns as complication of the use of electrosurgery. Burns are caused by local densifications of the current, but the actual pathway of current within patient’s body is unknown. Numerical electromagnetic analysis can help in understanding the issue.
To this aim, an accurate heterogeneous model of human body (including seventy-seven different tissues), electrosurgery electrodes, operating table and mattress was build to resemble a typical surgery condition. The patient lays supine on the mattress with the active electrode placed onto the thorax and the return electrode on his back. Common operating frequencies of electrosurgery units were considered. Finite Difference Time Domain electromagnetic analysis was carried out to compute the spatial distribution of current density within the patient’s body. A differential analysis by changing the electrical properties of the operating table from a conductor to an insulator was also performed.
Results revealed that distributed capacitive coupling between patient body and the conductive operating table offers an alternative path to the electrosurgery current. The patient’s anatomy, the positioning and the different electromagnetic properties of tissues promote a densification of the current at the head and sacral region. In particular, high values of current density were located behind the sacral bone and beneath the skin. This did not occur in the case of non-conductive operating table.
Results of the simulation highlight the role played from capacitive couplings between the return electrode and the conductive operating table. The concentration of current density may result in an undesired rise in temperature, originating burns in body region far from the electrodes. This outcome is concordant with the type of surgery-related sacral burns reported in literature. Such burns cannot be immediately detected after surgery, but appear later and can be confused with bedsores. In addition, the dosimetric analysis suggests that reducing the capacity coupling between the return electrode and the operating table can decrease or avoid this problem.
PMCID: PMC3751592  PMID: 23937865
Electrosurgery; Finite Difference Time Domain (FDTD) electromagnetic analysis; Detailed human tissues 3D model; Operating table; Capacitive coupling
13.  Patients’ experiences of cold exposure during ambulance care 
Exposure to cold temperatures is often a neglected problem in prehospital care. Cold exposure increase thermal discomfort and, if untreated causes disturbances of vital body functions until ultimately reaching hypothermia. It may also impair cognitive function, increase pain and contribute to fear and an overall sense of dissatisfaction. The aim of this study was to investigate injured and ill patients’ experiences of cold exposure and to identify related factors.
During January to March 2011, 62 consecutively selected patients were observed when they were cared for by ambulance nursing staff in prehospital care in the north of Sweden. The field study was based on observations, questions about thermal discomfort and temperature measurements (mattress air and patients’ finger temperature). Based on the observation protocol the participants were divided into two groups, one group that stated it was cold in the patient compartment in the ambulance and another group that did not. Continuous variables were analyzed with independent sample t-test, paired sample t-test and dichotomous variables with cross tabulation.
In the ambulance 85% of the patients had a finger temperature below comfort zone and 44% experienced the ambient temperature in the patient compartment in the ambulance to be cold. There was a significant decrease in finger temperature from the first measurement indoor compared to measurement in the ambulance. The mattress temperature at the ambulance ranged from −22.3°C to 8.4°C.
Cold exposure in winter time is common in prehospital care. Sick and injured patients immediately react to cold exposure with decreasing finger temperature and experience of discomfort from cold. Keeping the patient in the comfort zone is of great importance. Further studies are needed to increase knowledge which can be a base for implications in prehospital care for patients who probably already suffer for other reasons.
PMCID: PMC3693912  PMID: 23742143
Cold exposure; Comfort zone; Finger temperature; Thermal comfort; Thermal discomfort; Patients’ experience
14.  Heat loss from giant extinct reptiles. 
There is disagreement in the literature about the relative rates of heat loss from a large animal surrounded by either air or water. Here, it is shown that, in most circumstances, the rate at which heat is lost by a large body is significantly greater when it is immersed in water than when it is surrounded by air, assuming that the two fluids are at the same temperature. The only circumstance when this may not apply is when comparing air with fresh water when both are at a temperature somewhere between 0 degrees C and 6 degrees C, the animal is still and water or air currents are negligible. Under these conditions, free convection in water is weak or non-existent, and so the combined effect of conduction and free convection in air becomes comparable to or even greater than that of conduction alone in water. However, in these circumstances, radiation is the dominant mode of heat loss to both media, and so heat losses are approximately the same in both air and water.
PMCID: PMC1088828  PMID: 11564348
15.  Water warming garment versus forced air warming system in prevention of intraoperative hypothermia during liver transplantation: a randomized controlled trial [ISRCTN32154832] 
BMC Anesthesiology  2002;2:7.
The authors compared two strategies for the maintenance of intraoperative normothermia during orthotopic liver transplantation (OLT): the routine forced-air warming system and the newly developed, whole body water garment.
In this prospective, randomized and open-labelled study, 24 adult patients were enrolled in one of two intraoperative temperature management groups during OLT. The water-garment group (N = 12) received warming with a body temperature (esophageal) set point of 36.8°C. The forced air-warmer group (N = 12) received routine warming therapy using upper- and lower-body forced-air warming system. Body core temperature (primary outcome) was recorded intraoperatively and during the two hours after surgery in both groups.
The mean core temperatures during incision, one hour after incision and during the skin closing were significantly higher (p < 0.05, t test with Bonferroni corrections for the individual tests) in the water warmer group compared to the control group (36.7 ± 0.1, 36.7 ± 0.2, 36.8 ± 0.1 vs 36.1 ± 0.4, 36.1 ± 0.4, 36.07 ± 0.4°C, respectively). Moreover, significantly higher core temperatures were observed in the water warmer group than in the control group during the placement of cold liver allograft (36.75 ± 0.17 vs 36.09 ± 0.38°C, respectively) and during the allograft reperfusion period (36.3 ± 0.26 vs 35.52 ± 0.42°C, respectively). In addition, the core temperatures immediately after admission to the SICU (36.75 ± 0.13 vs 36.22 ± 0.3°C, respectively) and at one hr (36.95 ± 0.13 vs 36.46 ± 0.2°C, respectively) were significantly higher in the water warmer group, compared to the control group, whereas the core temperature did not differ significantly afte two hours in ICU in both groups.
The investigated water warming system results in better maintenance of intraoperative normothermia than routine air forced warming applied to upper- and lower body.
PMCID: PMC137608  PMID: 12441007
16.  Can latent heat safely warm blood? – in vitro testing of a portable prototype blood warmer 
Trauma/retrieval patients are often in shock and hypothermic. Treatment of such patients usually involves restoring their blood volume with transfusion of blood (stored at 2°C – 6°C) and/or crystalloids or colloids (stored at ambient temperature). Rapid infusion of these cold fluids can worsen or even induce hypothermia in these patients. Warming of intravenous fluids at accident sites has traditionally been difficult due to a lack of suitable portable fluid warmers that are not dependent on mains electrical or battery power. If latent heat, the heat released when a liquid solidifies (an inherently temperature limiting process) can warm intravenous fluids, portable devices without a reliance on electrical energy could be used to reduce the incidence of hypothermia in trauma patients.
Rapid infusion of red cells into patients was timed to sample typical clinical flow rates.
An approved dry heat blood warmer was compared with a prototype blood warmer using a supercooled liquid latent heat storage material, to warm red cells whilst monitoring inlet and outlet temperatures. To determine the effect of warming on red cell integrity compared to the normal storage lesion of blood, extracellular concentrations of potassium, lactate dehydrogenase and haemoglobin were measured in blood which had been warmed after storage at 2°C – 6°C for 1 to 42 days.
A prototype latent heat fluid warmer consistently warmed red cells from approximately 4°C to approximately 35°C at typical clinical flow rates. Warming of stored blood with latent heat did not affect red cell integrity more than the approved dry heat blood warmer.
Using latent heat as an energy source can satisfactorily warm cold blood or other intravenous fluids to near body temperature, without any adverse affects.
PMCID: PMC1988795  PMID: 17672912
17.  The Factors Associated with Contact Burns from Therapeutic Modalities 
Annals of Rehabilitation Medicine  2012;36(5):688-695.
To understand the injury pattern of contact burns from therapeutic physical modalities.
A retrospective study was done in 864 patients with contact burns who discharged from our hospital from January 2005 to December 2008. The following parameters were compared between patients with contact burns from therapeutic modalities and from other causes: general characteristics, burn extent, cause of burn injury, place of occurrence, burn injury site, treatment methods, prevalence of underlying disease, and length of hospital stay were compared between patients with contact burns.
Of the 864 subjects, 94 patients were injured from therapeutic modalities. A hot pack (n=51) was the most common type of therapeutic modality causing contact burn followed by moxibustion (n=21), electric heating pad (n=16), and radiant heat (n=4). The lower leg (n=31) was the most common injury site followed by the foot & ankle (n=24), buttock & coccyx (n=9), knee (n=8), trunk (n=8), back (n=6), shoulder (n=4), and arm (n=4). Diabetes mellitus was associated with contact burns from therapeutic modalities; the odds ratio was 3.99. Injuries took place most commonly at home (n=56), followed by the hospital (n=33), and in other places (n=5).
A hot pack was the most common cause of contact burns from therapeutic modalities, and the lower leg was the most common injury site. Injuries took place most commonly at home. The patients with contact burns from therapeutic modalities showed high correlation to presence of diabetes mellitus. These results would be helpful for the prevention of contact burns due to therapeutic modalities.
PMCID: PMC3503945  PMID: 23185734
Burns; Physical therapy modalities; Diabetes mellitus
18.  Human mitochondrial oxidative capacity is acutely impaired following burn trauma 
American journal of surgery  2008;196(2):234-239.
Mitochondrial proteins and genes are damaged after burn injury in animals but have not previously been assessed in human burn patients.
The rates of maximal muscle mitochondrial oxidative capacity(ATP production) and uncoupled oxidation(heat production) for both palmitate and pyruvate were measured in muscle biopsies from 40 children sustaining burns >40% body surface area and from 13 healthy children controls.
Maximal mitochondrial oxidation of pyruvate and palmitate were reduced in burn patients compared to controls (4.0±0.2:1.9±0.1 µmolO2/citrate synthase activity/mg protein/min pyruvate; Control:Burn;P<0.001 and 3.0±0.1:0.9±0.03 µmolO2/citrate synthase activity/mg protein/min palmatyl CoA; Control:Burn;P=0.003). Uncoupled oxidation was the same between groups.
The maximal coupled mitochondrial oxidative capacity is severely impaired after burn injury, although there are no alterations in the rate of uncoupled oxidative capacity. It may be that the ratio of these indicates that a larger portion of energy production in trauma patients is wasted through uncoupling, rather than used for healing.
PMCID: PMC3480314  PMID: 18639661
Trauma; burn; mitochondria; muscle
19.  Meperidine and skin surface warming additively reduce the shivering threshold: a volunteer study 
Critical Care  2007;11(1):R29.
Mild therapeutic hypothermia has been shown to improve outcome for patients after cardiac arrest and may be beneficial for ischaemic stroke and myocardial ischaemia patients. However, in the awake patient, even a small decrease of core temperature provokes vigorous autonomic reactions–vasoconstriction and shivering–which both inhibit efficient core cooling. Meperidine and skin warming each linearly lower vasoconstriction and shivering thresholds. We tested whether a combination of skin warming and a medium dose of meperidine additively would reduce the shivering threshold to below 34°C without producing significant sedation or respiratory depression.
Eight healthy volunteers participated on four study days: (1) control, (2) skin warming (with forced air and warming mattress), (3) meperidine (target plasma level: 0.9 μg/ml), and (4) skin warming plus meperidine (target plasma level: 0.9 μg/ml). Volunteers were cooled with 4°C cold Ringer lactate infused over a central venous catheter (rate ≈ 2.4°C/hour core temperature drop). Shivering threshold was identified by an increase of oxygen consumption (+20% of baseline). Sedation was assessed with the Observer's Assessment of Alertness/Sedation scale.
Control shivering threshold was 35.5°C ± 0.2°C. Skin warming reduced the shivering threshold to 34.9°C ± 0.5°C (p = 0.01). Meperidine reduced the shivering threshold to 34.2°C ± 0.3°C (p < 0.01). The combination of meperidine and skin warming reduced the shivering threshold to 33.8°C ± 0.2°C (p < 0.01). There were no synergistic or antagonistic effects of meperidine and skin warming (p = 0.59). Only very mild sedation occurred on meperidine days.
A combination of meperidine and skin surface warming reduced the shivering threshold to 33.8°C ± 0.2°C via an additive interaction and produced only very mild sedation and no respiratory toxicity.
PMCID: PMC2151895  PMID: 17316456
20.  Tympanic membrane temperature as a measure of core temperature 
Archives of Disease in Childhood  1999;80(3):262-266.
BACKGROUND—Ear thermometers are becoming popular as a method for measuring deep body (core) temperature.
AIM—To determine the variability of a single user's tympanic membrane (ear) temperature measurements.
SUBJECTS—Forty two, afebrile, healthy children, and 20 febrile children with acute burns.
RESULTS—In afebrile children measurements made in both ears (and within just a few minutes of each other) differed by as much as 0.6°C. Operator measurement error, sw of three consecutive measurements, in the same ear, was 0.13°C. In the group of febrile, burned children, core temperature was measured hourly at a number of sites (ear, rectum, axilla, bladder). A peak in core temperature occurred approximately 10-12 hours after the burn. Measurement error was calculated in 14 febrile, burned children with a peak temperature in excess of 38°C. For the left ear, measurement error was 0.19°C and for the right ear, 0.11°C. In the febrile children agreement between the ears was poor. The limits of agreement were 0.4°C to −0.8°C. It was not possible to predict the occasions when the temperature differences between the ears would be large or small.
CONCLUSIONS—The measurement error of one recording from the next is probably acceptable at about 0.1 to 0.2°C. To limit the variations in temperature of one ear to the other, measurements should be restricted to one of the ears whenever possible and the same ear used throughout the temperature monitoring period. Nurses and parents should take more than one temperature reading from the same ear whenever possible. 

PMCID: PMC1717865  PMID: 10325708
21.  Thermometry in children 
Accurate measurement of temperature is important for detection of fever and hypothermia in pediatric patients. Ideal temperature-measurement technique should be safe, easy, noninvasive, cost effective, time efficient, and should precisely reflect core body temperature. Pulmonary artery is the closest to hypothalamus and best reflects the core temperature. Other sites used are distal esophagus, urinary bladder and nasopharynx. All these methods are invasive and difficult to use in clinical practice. Amongst the noninvasive methods, rectal thermometry is considered to be the closest to core temperature, but it has its own drawbacks. With the current evidence available, tympanic artery thermometry for children more than 2 years of age and temporal artery thermometry in all age groups are taking precedence over other methods.
PMCID: PMC3440892  PMID: 22988404
Children; temperature measurement; fever
22.  Changes in the Levels of Interleukins 6, 8, and 10, Tumor Necrosis Factor Alpha, and Granulocyte-colony Stimulating Factor in Korean Burn Patients: Relation to Burn Size and Postburn Time 
Annals of Laboratory Medicine  2012;32(5):339-344.
Major burn injury induces an inflammatory response that is accompanied by the release of various cytokines. We investigated the gradual changes in the levels of pro-inflammatory and anti-inflammatory cytokines following burn injury and determined the relationship between these levels and burn size in adult Korean patients with burn injury.
Blood samples from 9 healthy controls and 60 Korean burn patients were collected on days 1, 3, 7, 14, and 21 after burn injury, and concentrations of interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, and granulocyte-colony stimulating factor (G-CSF) were measured. Burn patients were divided into 3 groups according to burn size (15-30%, 31-50%, >50% total body surface area), and the concentrations of the cytokines were compared between these groups and the control group over 3 weeks.
Compared to their levels in controls, IL-6, IL-8, IL-10, TNF-α, and G-CSF levels in burn patients were significantly higher during the observation period. Median concentrations of IL-8, IL-10, and G-CSF at each time point increased with burn size, although peak levels and time to peak levels of these cytokines differed from patient to patient.
These findings indicate that IL-6, IL-8, IL-10, TNF-α, and G-CSF are important mediators in inflammatory changes after burn injury; however, various factors, including burn size, may influence the concentrations of these cytokines.
PMCID: PMC3427821  PMID: 22950069
Burns; Cytokines; Body surface area; Time
23.  The rewarming benefit of anterior torso heat pad application in mildly hypothermic conscious adult trauma patients remains inconclusive 
The rewarming benefit of anterior torso heat pad application in mildly hypothermic conscious adult trauma patients remains inconclusive in this randomized comparative clinical trial. There was no between-group rewarming gain in ear canal temperature when an anterior torso chemical heat pad was compared with blankets. Patient awareness, and favorable perception of, being administered the active intervention (heat pad) could explain the significant improvement in patient-rated cold discomfort discerned with the heat pad. In the context of marginal demonstrated benefit, it would have been informative to ascertain adverse effects related to the heat pad, including burn injury to the chest wall.
PMCID: PMC3314547  PMID: 22385688
Hypothermia; Trauma; Rewarming; Heat pad
24.  The effect of warmed inspired gases on body temperature during arthroscopic shoulder surgery under general anesthesia 
Perioperative hypothermia can develop easily during shoulder arthroscopy, because cold irrigation can directly influence core body temperature. The authors investigated whether active warming and humidification of inspired gases reduces falls in core body temperature and allows redistribution of body heat in patients undergoing arthroscopic shoulder surgery under general anesthesia.
Patients scheduled for arthroscopic shoulder surgery were randomly assigned to receive either room temperature inspired gases using a conventional respiratory circuit (the control group, n = 20) or inspired gases humidified and heated using a humidified and electrically heated circuit (HHC) (the heated group, n = 20).
Core temperatures were significantly lower in both groups from 30 min after anesthesia induction, but were significantly higher in the heated group than in the control group from 75 to 120 min after anesthesia induction.
In this study the use of a humidified and electrically heated circuit did not prevent core temperature falling during arthroscopic shoulder surgery, but it was found to decrease reductions in core temperature from 75 min after anesthesia induction.
PMCID: PMC3726840  PMID: 23904934
Arthroscopy; Circuit; General anesthesia; Shoulder; Temperature
25.  Measurements of Flat-Flame Velocities of Diethyl Ether in Air 
Energy (Oxford, England)  2012;43(1):140-145.
This study presents new adiabatic laminar burning velocities of diethyl ether in air, measured on a flat-flame burner using the heat flux method. The experimental pressure was 1 atm and temperatures of the fresh gas mixture ranged from 298 to 398 K. Flame velocities were recorded at equivalence ratios from 0.55 to 1.60, for which stabilization of the flame was possible. The maximum laminar burning velocity was found at an equivalence ratio of 1.10 or 1.15 at different temperatures. These results are compared with experimental and computational data reported in the literature. The data reported in this study deviate significantly from previous experimental results and are well-predicted by a previously reported chemical kinetic mechanism.
PMCID: PMC3662209  PMID: 23710107
Laminar burning velocity; Diethyl ether; DEE; High temperature; Combustion

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