Warming Blanket Research Articles

Aero-thermal optimization of in-flight electro-thermal ice protection systems in transient de-icing mode

Even if electro-thermal ice protection systems (IPS) consume less energy when operating in de-icing mode than in anti-icing mode, they still need to be optimized for energy usage. The optimization, however, should also take into account the effect of the de-icing system on the aerodynamic performance. The present work offers an optimization framework in which both thermal and aerodynamic viewpoints are taken into account in formulating various objective and constraint functions by considering the energy consumption, the thickness, the volume, the shape and the location of the accreted ice on the surface as the key parameters affecting the energy usage and the aerodynamic performance. The design variables include the power density and the activation time of the electric heating blankets. A derivative-free technique, called the mesh adaptive direct search (MADS) method, is used to carry out the optimization process, which would normally need a large number of unsteady conjugate heat transfer (CHT) calculations for the IPS simulation. To avoid such prohibitive computations, reduced-order modeling (ROM) is used to construct simplified low-dimensional CHT models. The approach is illustrated through several test cases, in which different combinations of objective and constraint functions, design variables and cycling sequence patterns are examined. In these test cases, the energy consumption is significantly reduced compared to the experiments by improving the spatial and temporal distribution of the thermal energy usage. The results show the benefits of the approach in bringing energy, safety and aerodynamic considerations together in designing de-icing systems.

Shock and annealing in aubrites: Implications for parent‐body history

AbstractSeveral aubrites (e.g., LAP 03719, Bishopville, Khor Temiki, ALH 83015) contain orthopyroxene grains that exhibit more‐pronounced shock effects than associated olivine grains. The orthopyroxene grains in these samples have clinoenstatite lamellae on (100) and exhibit weak mosaic extinction, characteristic of shock stage S4; the olivine grains exhibit either sharp optical extinction, characteristic of shock stage S1 (as in LAP 03719), or undulose extinction (shock stage S2), as in Bishopville and ALH 83015. The Khor Temiki regolith breccia contains S1 and S2 olivine grains. Because literature data show that diffusion is much slower in orthopyroxene than in olivine, it seems likely that aubrites experienced postshock, impact‐induced annealing. After differentiation, the aubrite parent asteroid suffered major collisions that caused extensive brecciation of near‐surface materials and damaged orthopyroxene and olivine crystal lattices. As a result of these impact events, some aubrites were shocked and buried within warm ejecta blankets or beneath fallback debris under the crater floor. Entombed olivine crystal lattices healed (and became unstrained, reaching shock stage S1), but orthopyroxene lattices retained their S4‐level shock‐damaged features. Aubrites with S4 orthopyroxene and S2 olivine were probably very weakly shocked again after olivine was annealed to S1.

Advances in the optimisation of apparel heating products: A numerical approach to study heat transport through a blanket with an embedded smart heating system

The optimisation of the performance of products with smart/active functionalities (e. g. in protective clothing, home textiles products, automotive seats, etc.) is still a challenge for manufacturers and developers. The aim of this study was to optimise the thermal performance of a heating product by a numerical approach, by analysing several opposing requirements and defining solutions for the identified limitations, before the construction of the first prototype. A transfer model was developed to investigate the transport of heat from the skin to the environment, across a heating blanket with an embedded smart heating system. Several parameters of the textile material and of the heating system were studied, in order to optimise the thermal performance of the heating blanket. Focus was put on the effects of thickness and thermal conductivity of each layer, and on parameters associated with the heating elements, e.g. position of the heating wires relative to the skin, distance between heating wires, applied heating power, and temperature range for operation of the heating system. Furthermore, several configurations of the blanket (and corresponding heating powers) were analysed in order to minimise the heat loss from the body to the environment, and the temperature distribution along the skin. The results show that, to ensure an optimal compromise between the thermal performance of the product and the temperature oscillation along its surface, the distance between the wires should be small (and not bigger than 50 mm), and each layer of the heating blanket should have a specific thermal resistance, based on the expected external conditions during use and the requirements of the heating system (i.e. requirements regarding energy consumption/efficiency and capacity to effectively regulate body exchanges with surrounding environment). The heating system should operate in an ON/OFF mode based on the body heating needs and within a temperature range specified based on the blanket total thermal resistance, external temperature during use, and observed temperature on the blanket outer surface (safety and energy efficiency aspects).The approach described in this work enabled the definition of the textile properties, the features of the embedded heating system, and the overall design of the system thus reducing substantially the number of prototypes needed for the final performance optimisation and fine-tuning.

Vasopressin decreases pulmonary-to-systemic vascular resistance ratio in a porcine model of severe hemorrhagic shock.

Vasopressors are gaining renewed interest as treatment adjuncts in hemorrhagic shock. The ideal vasoconstrictor will increase systemic blood pressure without increasing pulmonary vascular resistance (PVR), which hinders pulmonary perfusion and exacerbates hypoxemia. However, the selectivity of pressors for pulmonary versus systemic vasoconstriction during hemorrhage has not been characterized. The purpose of this study was to test the hypothesis that vasopressin (VP) has distinct effects on pulmonary versus systemic hemodynamics, unlike the catecholamine vasopressors norepinephrine (NE) and phenylephrine (PE). Anesthetized and ventilated pigs were assigned to resuscitation with saline only (n = 7) or saline with VP (n = 6), NE (n = 6), or PE (n = 6). Animals were hemorrhaged to a target volume of 30 mL/kg and a mean arterial pressure of 35 mmHg. One hour after the start of hemorrhage, animals were resuscitated with saline up to one shed blood volume, followed by either additional saline or a vasopressor. Hemodynamics and oxygenation were measured hourly for 4 h after the start of hemorrhage. Vasopressin increased systemic vascular resistance (SVR) while sparing the pulmonary vasculature, leading to a 45% decrease in the PVR/SVR ratio compared with treatment with PE. Conversely, NE induced pulmonary hypertension and led to an increased PVR/SVR ratio associated with decreased oxygen saturation. Phenylephrine and crystalloid had no significant effect on the PVR/SVR ratio. Sparing of pulmonary vasoconstriction occurs only with VP, not with administration of crystalloid or catecholamine pressors. The ability of VP to maintain blood oxygenation indicates that VP may prevent hypoxemia in the management of hemorrhagic shock.

Report of a pilot study of Cooling four preterm infants 32-35 weeks gestation with HIE.

This report reviews the use of the Cool-Cap device to apply selective therapeutic hypothermia to the brain of preterm infants, without causing systemic hypothermia. Four infants, 32–35 weeks gestation, with suspected Hypoxic Ischemic Encephalopathy (HIE) received treatment aimed at providing select ive brain cooling. It was not possible to apply cold circulating water to the scalp of the preterm infant without systemic hypothermia unless a warming blanket was also used. All infants had severe HIE and all had either death, or neurologic disability despite cooling attempts. Therapeutic hypothermia cannot be recommended at this time for preterm infants outside clinical trials.

Temperature modulation with an esophageal heat transfer device - a pediatric swine model study.

BackgroundAn increasing number of conditions appear to benefit from control and modulation of temperature, but available techniques to control temperature often have limitations, particularly in smaller patients with high surface to mass ratios. We aimed to evaluate a new method of temperature modulation with an esophageal heat transfer device in a pediatric swine model, hypothesizing that clinically significant modulation in temperature (both increases and decreases of more than 1°C) would be possible.MethodsThree female Yorkshire swine averaging 23 kg were anesthetized with inhalational isoflurane prior to placement of the esophageal device, which was powered by a commercially available heat exchanger. Swine temperature was measured rectally and cooling and warming were performed by selecting the appropriate external heat exchanger mode. Temperature was recorded over time in order to calculate rates of temperature change. Histopathology of esophageal tissue was performed after study completion.ResultsAverage swine baseline temperature was 38.3°C. Swine #1 exhibited a cooling rate of 3.5°C/hr; however, passive cooling may have contributed to this rate. External warming blankets maintained thermal equilibrium in swine #2 and #3, demonstrating maximum temperature decrease of 1.7°C/hr. Warming rates averaged 0.29°C/hr. Histopathologic analysis of esophageal tissue showed no adverse effects.ConclusionsAn esophageal heat transfer device successfully modulated the temperature in a pediatric swine model. This approach to temperature modulation may offer a useful new modality to control temperature in conditions warranting temperature management (such as maintenance of normothermia, induction of hypothermia, fever control, or malignant hyperthermia).

The efficacy of pre-warming on reducing intraprocedural hypothermia in endovascular coiling of cerebral aneurysms.

BackgroundThe anesthetic management of patients undergoing endovascular treatment of cerebral aneurysms in the interventional neuroradiology suite can be challenged by hypothermia because of low ambient temperature for operating and maintaining its equipments. We evaluated the efficacy of skin surface warming prior to induction of anesthesia to prevent the decrease in core temperature and reduce the incidence of hypothermia.MethodsSeventy-two patients were randomized to pre-warmed and control group. The patients in pre-warmed group were warmed 30 minutes before induction with a forced-air warming blanket set at 38°C. Pre-induction tympanic temperature (Tpre) was measured using an infrared tympanic thermometer and core temperature was measured at the esophagus immediately after intubation (T0) and recorded at 20 minutes intervals (T20, T40, T60, T80, T100, and T120). The number of patients who became hypothermic at each time was recorded.ResultsTpre in the control and pre-warmed group were 36.4 ± 0.4°C and 36.6 ± 0.3°C, whereas T0 were 36.5 ± 0.4°C and 36.6 ± 0.2°C. Core temperatures in the pre-warmed group were significantly higher than the control group at T20, T40, T60, T80, T100, and T120 (P < 0.001). Compared to T0, core temperatures at each time were significantly lower in both two groups (P = 0.007 at T20 in pre-warmed group, P < 0.001 at the other times in both groups). The incidence of hypothermia was significantly lower in the pre-warmed group than the control group from T20 to T120 (P = 0.002 at T20, P < 0.001 at the other times).ConclusionPre-warming for 30 minutes at 38°C did not modify the trends of the temperature decrease seen in the INR suite. It just slightly elevated the beginning post intubation base temperature. The rate of decrease was similar from T20 to T120. However, pre-warming considerably reduced the risk of intraprocedural hypothermia.Trial registrationClinical Research Information Service (CRiS) Identifier: KCT0001320. Registered December 19th, 2014.

A rare case of postpoliomyelitis quadriparetic patient with severe kyphoscoliosis.

A rare case of postpoliomyelitis quadriparetic patient with severe kyphoscoliosis.

Paroxysmal cold hemoglobinuria in an elderly patient: A rare case with poor prognosis

Introduction: Paroxysmal cold hemoglobinuria (PcH) is a very rare type of cold-mediated autoimmune hemolytic anemia causing direct intravascular hemolysis and hemoglobinuria, typically after exposure to cold. the reaction is caused by an IgG antibody known as DonathLandsteiner (D-L), which binds specifically to the P antigen of red blood cells at low temperatures, leading to complement activation and red cell lysis. case report: We report a case of rare occurrence of acute syphilitic paroxysmal cold hemoglobinuria in an elderly female with evidence of intravascular hemolysis complicated with peripheral gangrene and multiple organ dysfunctions. conclusion: the prognosis of PcH associated with syphilis is usually considered excellent and benign. However, we encountered a syphilitic PcH in an elderly female with a grave prognosis who passed away within five months after her first episode. based on our case experience, we recommend that acute episodes of PcH in an elderly patient should be treated in a closely monitored setting with high dose of steroids and warm blankets.

Clinical considerations in the use of forced-air warming blankets during orthognathic surgery to avoid postanesthetic shivering.

BackgroundDuring head and neck surgery including orthognathic surgery, mild intraoperative hypothermia occurs frequently. Hypothermia is associated with postanesthetic shivering, which may increase the risk of other postoperative complications. To improve intraoperative thermoregulation, devices such as forced-air warming blankets can be applied. This study aimed to evaluate the effect of supplemental forced-air warming blankets in preventing postanesthetic shivering.MethodsThis retrospective study included 113 patients who underwent orthognathic surgery between March and September 2015. According to the active warming method utilized during surgery, patients were divided into two groups: Group W (n = 55), circulating-water mattress; and Group F (n = 58), circulating-water mattress and forced-air warming blanket. Surgical notes and anesthesia and recovery room records were evaluated.ResultsInitial axillary temperatures did not significantly differ between groups (Group W = 35.9 ± 0.7℃, Group F = 35.8 ± 0.6℃). However, at the end of surgery, the temperatures in Group W were significantly lower than those in Group F (35.2 ± 0.5℃ and 36.2 ± 0.5℃, respectively, P = 0.04). The average body temperatures in Groups W and F were, respectively, 35.9 ± 0.5℃ and 36.2 ± 0.5℃ (P = 0.0001). In Group W, 24 patients (43.6%) experienced postanesthetic shivering, while in Group F, only 12 (20.7%) patients required treatment for postanesthetic shivering (P = 0.009, odds ratio = 0.333, 95% confidence interval: 0.147–0.772).ConclusionsAdditional use of forced-air warming blankets in orthognathic surgery was superior in maintaining normothermia and reduced the incidence of postanesthetic shivering.

Resistive embedded heating for homogeneous curing of adhesively bonded joints

Adhesively bonded single-lap joints with laminated composite adherends were cured using heat generated by passing an electrical current through a carbon fiber fabric embedded in the bondline. Resistance heating using the embedded fabric resulted in a uniform temperature distribution in the bondline, as compared to temperature fields typically generated using more conventional surface heating methods such as heat blankets or heat lamps. Composite single-lap joint specimens were created using the proposed embedded heating approach, via an oven cure under a vacuum and through the use of an autoclave. The bond strengths of all specimens were measured and found to be comparable. The proposed embedded curing technique results in bond strengths that equal or exceed those achieved with conventional methods, and at potentially lower cost.

Editorial Comment: Manufacturer's Response to Thermal Burn Associated with Intraoperative Convective Forced-Air Warming Blanket (Bair Paws™ Flex Gown System).

Editorial Comment: Manufacturer's Response to Thermal Burn Associated with Intraoperative Convective Forced-Air Warming Blanket (Bair Paws™ Flex Gown System).

Thermal burn associated with intraoperative convective forced-air warming blanket (bair paws™ flex gown system).

A 44-year-old man undergoing ambulatory surgery sustained a 5% total body surface first-degree burn on his lower and lateral torso and upper thigh during routine use of a new forced-air warming Bair Paws™ flex gown system. We describe the likely mechanism of injury, intraoperative events suggesting special variation in the warming process, and a brief review of adverse events associated with forced-air warming systems.

Preoperative factors affecting the intraoperative core body temperature in abdominal surgery under general anesthesia: an observational cohort.

The study was conducted to identify preoperative factors affecting the intraoperative core body temperature in abdominal surgery under general anesthesia. This study was performed through prospective descriptive research design. The setting was a 1300-bed university hospital in Incheon, South Korea. The sample consisted of 147 patients who had undergone elective abdominal surgery under general anesthesia. Age, weight, and height were collected on a preoperative visit to general unit, and body mass index, body surface area, and total body fat were calculated. The basal preoperative core body temperature (CBT), preoperative blood pressure, and heart rate were measured. Core body temperature was again measured at 1, 2, and 3 hours following general anesthesia. Predictive factors of intraoperative hypothermia of less than 36°C were preoperative CBT (β = .44), weight (β = .41), preoperative heart rate (β = .20), and age (β = -.13) at 1 hour after anesthesia (R = 0.658, F = 68.3, P < .001); preoperative CBT (β = .33), weight (β = .37), preoperative heart rate (β = .22), and age (β = -.24) at 2 hours after anesthesia (R = 0.631, F = 60.8, P < .001); and age (β = -.34), weight (β = .36), preoperative CBT (β = .30), and preoperative heart rate (β = .20) at 3 hours after anesthesia (R = 0.665, F = 70.6, P < .001). Low preoperative body temperature and low weight seem to be risk factors of intraoperative hypothermia during 2 hours after anesthesia and advanced age and low weight at 3 hours following anesthesia. We recommend prewarming and intraoperative warming through forced air warming devices and covering a patient with a warm blanket during transportation. This procedure is necessary for the abdominal surgical patients of advanced age with low weight and duration of general anesthesia to last more than 1 hour.

Medication Safety: Does Intravenous Acetaminophen Promote Perioperative Hypothermia for Total Hip Arthroplasty?

As an effective antipyretic with a yet-unknown mechanism-of-action, intravenous (IV) acetaminophen use for total hip arthroplasties (THA) may worsen perioperative hypothermia when combined with the known hypothermia-inducing effects of general anesthesia (GA), affecting wound healing, recovery times, and patient satisfaction. This retrospective chart review of primary THA cases compared perioperative heat loss for patients who received IV acetaminophen with GA (group A, n = 74) to those receiving GA alone (group B, n = 197). All patients received forced-air warming blankets. Neuraxial anesthesia cases were excluded. No significant temperature differences existed between group A (–0.33°C, SD = 0.36) and group B (–0.30°C, SD = 0.34, P > 0.05). IV acetaminophen use for THA does not appear to promote hypothermia under general anesthesia.

A commentary on the role of skin temperature on the effectiveness of ALA-PDT in Dermatology

The review of several studies indicates clearly that improving ALA-PDT of skin lesions might be achieved by elevating the skin temperature during the ALA application. Several mechanisms could be responsible: a better ALA uptake and/or an higher PpIX production into cells due to an improved enzymatic process, mainly due to the increased activity of ferrochelatase. Vasodilatation of skin vessels could also increase the oxygen supply and consequently enhances the generation of singlet oxygen, and other cytotoxic species. Different techniques can be used to perform an elevation of skin temperature: IRA, heating blanket, etc. At last, skin heating could increase the penetration (depth) of ALA into the skin, which thereby may increase PpIX production (in deeper layers) in the skin. This could represent an interesting approach to improving ALA-PDT of nodular BCC and other skin lesions.

A novel rat model of cardiopulmonary bypass for deep hypothermic circulatory arrest without blood priming

Background Large animal cardiopulmonary bypass (CPB) models are expensive, and prevent assessment of neurocognitive function, and difficulties with long-term recovery. The purpose of this study was to establish a novel rat model of cardiopulmonary bypass for deep hypothermic circulatory arrest without blood priming. Methods Twenty adult male Sprague-Dawley rats weighing 450–560 g were randomized to CPB with deep hypothermic circulatory arrest (DHCA) and control groups, with 10 rats each. The experimental protocols, including blood and crystalloid fluid administration, anesthesia, orotracheal intubation, ventilation, cannulation, and heparinization were identical in both groups. After inducing cardiac arrest, the circuit was turned off and rats were left in a DHCA state for 15 minutes. Rats were rewarmed to 34°C to 35°C over a period of 36 to 42 minutes using CPB-assisted rewarming, a heating blanket, and a heating lamp along with administration of 0.1 mEq of sodium bicarbonate and 0.14 mEq of calcium chloride. The remaining priming volume was reinfused and animals were weaned from CPB. Results All CPB with DHCA processes were successfully achieved. Blood gas analysis and hemodynamic parameters were in the normal range. The vital signs of all rats were stable. Conclusions Our CPB circuit has several novel features, including a small priming volume, active cooling/rewarming processes, vacuum-assisted venous drainage, peripheral cannulation without thoracotomy or sternotomy, and an accurate means of monitoring peripheral tissue oxygenation.

Use of Resuscitative Endovascular Balloon Occlusion of the Aorta in a Highly Lethal Model of Noncompressible Torso Hemorrhage

Noncompressible torso hemorrhage is a leading cause of death in trauma, with many patients dying before definitive hemorrhage control. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an adjunct than can be used to expand the window of salvage in patients with end-stage hemorrhagic shock. The aim of this study was to evaluate the effect of continuous and intermittent REBOA (iREBOA) on mortality using a highly lethal porcine model of noncompressible torso hemorrhage. Male splenectomized pigs (70-90 kg) underwent a laparoscopic liver injury (80% resection of left lobe) followed by a 10-min free-bleed period. Animals were then divided into three groups (n = 8) for a 60-min intervention phase (n = 8): continuous occlusion (cREBOA), iREBOA, or no occlusion (nREBOA). Groups then underwent whole blood resuscitation, damage control surgery, and further critical care. Endpoints were mortality and hemodynamic and circulating measures of shock and resuscitation. Systolic blood pressure (in mmHg) at the end of the free-bleed period for cREBOA, iREBOA, and nREBOA was 31 ± 14, 48 ± 28, and 28 ± 17, respectively (P = 0.125). Following the start of the intervention phase, systolic blood pressure was higher in the iREBOA and cREBOA groups compared with the nREBOA (85 ± 37 and 96 ± 20 vs. 42 ± 4; P < 0.001). Overall mortality for the cREBOA, iREBOA, and nREBOA groups was 25.0%, 37.5%, and 100.0% (P = 0.001). Resuscitative endovascular balloon occlusion of the aorta can temporize exsanguinating hemorrhage and restore life-sustaining perfusion, bridging critical physiology to definitive hemorrhage control. Prospective observational studies of REBOA as a hemorrhage control adjunct should be undertaken in appropriate groups of human trauma patients.

Forced-air warming blanket application of nursing research in the operation of radical resection of colon ;cancer

Objective To probe into the value of forced-air warming blanket to prevent the body temperature drop of surgical patients during operation .Methods A total of 60 colon cancer patients accepting radical operation under general anesthesia were randomly divided into test and control group .During the operation, control group cases received operation at room temperature .Except during the heating operation of intravenous fluid , blood and warming peritoneal lavage fluid ,with no use of forced-air warming blanket .Patients of test group had received their operation on the forced-air warming blanket in surgical bed , except during the heating operation of intravenous fluid , blood and warming peritoneal washings . Then changes of body temperature, PT, APTT, PLT of the two group cases were observed .Results Control group compared with test group, no significant difference was found at the beginning of the operation temperature [（36.4 ±0.3 vs 36.3 ± 0.4）℃,t=0.319, P>0.05], the operation temperature at the end of the control group was significantly lower than that in test group [（35.5 ±0.4 vs 36.5 ±0.3）℃,t=4.984, P 0.05 ）;. Conclusions During the radical resection of colon cancer ,forced-air warming blanket can effectively reduce the occurrence of peri-operation period of low temperature and low temperature related complication . Key words: Colon cancer; Surgery; Nursing; Forced-air warming blanket

Anesthesia in patients with arthrogryposis multiplex congenita: a report of 10 patients.

Anesthesia in patients with arthrogryposis multiplex congenita: a report of 10 patients.