The effect of ohmic heating conditions and heating modes on gel properties of unwashed pre-rigor common carp (Cyprinus carpio) surimi.

Ohmic heating (OH) at different conditions (voltage: 15, 20, 25 V; frequency: 1, 5, 10 kHz) and one-step water bath (WB) were used to heat wash and unwash surimi prepared from fresh pre-rigor common carp. The optimal heating conditions were established through assessments of gel strength, Texture Profile Analysis (TPA), water-holding capacity (WHC), whiteness, and sensory evaluation. Then, the impact of heating modes on gelation properties of unwashed surimi based on the optimal heating conditions was investigated. The study findings indicated a significant enhancement in gel properties compared to WB. Unwashed surimi gel properties showed improvement when derived from freshly caught raw fish and subjected to OH treatment. Moreover, variations in frequencies and voltages were observed to influence the heating rate. Optimal gel quality was achieved at 10 kHz 20 V (10 V/cm), facilitating swift progression through the gel deterioration stage, inhibition of protein hydrolyzing enzymes activity, and establishment of a stable gel network. Continuing to increase the heating rate would disrupt its network structure, resulting in diminished gel strength and WHC. The best quality of unwashed surimi gel was achieved by heating to 40°C for 30 min, followed by heating to 90°C for another 30 min (40°C 30 min + 90°C 30 min) under 10 kHz 20 V. The gel strength increased when held for 1 h at 40°C. For optimal heating efficiency, the heating mode of 40°C 30 min + 90°C 30 min is recommended to prepare unwashed surimi gel. PRACTICAL APPLICATION: Ohmic heating, as a rapid food heat treatment method, can both increase the heating rate and improve the gelation properties of freshwater surimi. There is a wide range of potential applications for the heat treatment of the surimi.

Biofilm on total joint replacement materials can be reduced through electromagnetic induction heating using a portable device.

BACKGROUND: Periprosthetic joint infection is a serious complication following joint replacement. The development of bacterial biofilms bestows antibiotic resistance and restricts treatment via implant retention surgery. Electromagnetic induction heating is a novel technique for antibacterial treatment of metallic surfaces that has demonstrated in-vitro efficacy. Previous studies have always employed stationary, non-portable devices. This study aims to assess the in-vitro efficacy of induction-heating disinfection of metallic surfaces using a new Portable Disinfection System based on Induction Heating. METHODS: Mature biofilms of three bacterial species: S. epidermidis ATCC 35,984, S. aureus ATCC 25,923, E. coli ATCC 25,922, were grown on 18 × 2 mm cylindrical coupons of Titanium-Aluminium-Vanadium (Ti6Al4V) or Cobalt-chromium-molybdenum (CoCrMo) alloys. Study intervention was induction-heating of the coupon surface up to 70ºC for 210s, performed using the Portable Disinfection System (PDSIH). Temperature was monitored using thermographic imaging. For each bacterial strain and each metallic alloy, experiments and controls were conducted in triplicate. Bacterial load was quantified through scraping and drop plate techniques. Data were evaluated using non-parametric Mann-Whitney U test for 2 group comparison. Statistical significance was fixed at p ≤ 0.05. RESULTS: All bacterial strains showed a statistically significant reduction of CFU per surface area in both materials. Bacterial load reduction amounted to 0.507 and 0.602 Log10 CFU/mL for S. aureus on Ti6Al4V and CoCrMo respectively, 5.937 and 3.500 Log10 CFU/mL for E. coli, and 1.222 and 0.372 Log10 CFU/mL for S. epidermidis. CONCLUSIONS: Electromagnetic induction heating using PDSIH is efficacious to reduce mature biofilms of S aureus, E coli and S epidermidis growing on metallic surfaces of Ti6Al4V and CoCrMo alloys.

Evaluation of Thermal Support during Anesthesia Induction on Body Temperature in C57BL/6 and Nude Mice.

Heat supplementation during surgery is a common practice; however, thermal support is not commonly used during anesthesia induction. Mice lose body temperature quickly, and air movement can exacerbate this, potentially putting mice at a thermal deficit before surgery. Whether the method of warming during induction affects overall heat loss during anesthesia is unknown. We hypothesized that the method of heating would affect body temperature (Tb) during anesthesia induction, maintenance, recovery, and once placed back on the rack. Mice (C57BL/6NHsd-6M/6F [C57BL/6]; Hsd:Athymic Nude-Foxn1nu [Nude]; N = 24;12M/12F) were assigned to a treatment in a factorial design: thermal chamber (TC; ambient temperature [Ta] = 28.8°C); heating pad (HP; induction chamber placed on an electric heating pad;Ta = 28.4°C); and control (Ctrl; Ta = 21.6°C). During induction, one mouse at a time was anesthetized with isoflurane over a 3min period and then maintained under anesthesia for 10min on a hot water heating pad (33 °C). Then isoflurane was stopped and time to ambulation was recorded. Tb and activity were tracked in the home cage on the rack before and after anesthesia. During induction, Ctrl mice lost significantly more heat (-2.8 °C) than did TC (+0.2 °C) and HP mice (+0.1 °C) but TC and HP were not different. During anesthesia maintenance, Ctrl mice regained 1 °C, but their Tb was still lower than that of the treated groups. Nude mice consistently had a lower Tb than C57BL/6 mice, regardless of treatment or anesthesia phase. C57BL/6 Ctrl mice took longer to ambulate than either HP or TC mice, but the method of heating did not differentially affect Nude mice. In general, C57BL/6 as compared with Nude and females as compared with males were comparatively more active and had higher Tb during certain times of day, regardless of the heating methods. Overall, our findings support the provision of heat during anesthesia induction, regardless of method, to reduce overall Tb loss during a short anesthesia event.

Household heating fuels impact on Acute Respiratory Infection (ARI) symptoms among children in Punjab, Pakistan.

Exposure to household air pollution (HAP) accounted for the loss of 86 million healthy lives in 2019, with almost half of all deaths due to lower respiratory infection among children under 5 years of age. Similarly, the situation in Punjab - Pakistan's largest province - is also not promising. This study was conducted to examine household energy consumption and respiratory symptoms among children under the age of five in rural and urban areas of Punjab. Using data from the Multiple Indicator Cluster Survey (MICS) 2017-18, logistic regression models were applied to the data of a sample of 35,000 children under the age of five living in households with polluting heating fuels. A hypothesis was formulated to investigate the relationship between polluting heating activities and respiratory infections among children under five. Those Children who live in households having traditional space heaters without chimneys are 50% more likely to have symptoms of Acute Respiratory Infection (ARI) compared to those whose households have chimneys with traditional space heaters. When households utilize polluting heating fuel, the likelihood of children experiencing rapid, shortness of breath increases by 49%, and the likelihood of children displaying ARI symptoms characterized by coughing rises by approximately 30%. This study proposed a complete banning of polluting heating activities and replacing it with cleaner ones using financial incentives. It is pertinent to raise awareness campaigns majorly focusing on the guidelines to adopt better heat output with less harmful emissions.

Microwave-Induced Transient Heating Accelerates Protein PEGylation.

PEGylation is one of the most widely employed strategies to increase the circulatory half-life of proteins and to reduce immune responses. However, conventional PEGylation protocols often require excess reagents and extended reaction times because of their inefficiency. This study demonstrates that a microwave-induced transient heating phenomenon can be exploited to significantly accelerate protein PEGylation and even increase the degree of PEGylation achievable beyond what is possible at room temperature. This can be accomplished under conditions that do not compromise protein integrity. Several PEGylation chemistries and proteins are tested, and mechanistic insight is provided. Under certain conditions, extremely high levels of PEGylation were achieved in a matter of minutes. Moreover, considering the significantly reduced reaction times, the microwave-induced transient heating concept was adapted for continuous flow manufacturing of bioconjugates.

Double-nozzle 3D-printed bean paste buns: Effect of filling ratio and microwave heating time.

With the aggravation of the global aging process, more and more elderly people are facing the problem of dysphagia. The advantages of three-dimensional (3D) printing in making chewy food are increasingly prominent. In this study, the two-nozzle 3D printer was used to explore the effects of different proportions of buckwheat flour, printing filling ratio, microwave power, and time on the quality of bean-paste buns. The results showed that the bean paste filling containing 6% buckwheat flour had the best antioxidant and sensory properties. When the filling ratio was 21.6%, the microwave power was 560 W, and the time was 4 min, the obtained sample was the most satisfactory. Compared with the microwave-treated and steamed traditional samples, the chewiness of the samples was reduced by 52.43% and 15.14%, respectively, and the final product was easier to chew and swallow.

Synergistic effects of 915 MHz microwave heating and essential oils on inactivation of foodborne pathogen in hot-chili sauce.

Essential oil is a food additive with antimicrobial properties but with limitations due to strong organoleptic properties. However, thermal treatments can be applied to reduce essential oil content while ensuring antimicrobial activities in food matrices. In this study, the inactivation efficiency of essential oils on E. coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in buffered peptone water (BPW) and hot-chili sauce was evaluated when coupled with 915 MHz microwave heating. Essential oils used in this study did not affect the dielectric properties and further heating rate of BPW and hot-chili sauce. The dielectric constant of BPW was 76.3 and dielectric loss factor was 30.9. In addition, it took 85 s to reach 100 °C for all samples. Among essential oils, synergistic microbial inactivation with microwave heating was observed from carvacrol (CL) and citral (CI), but not from eugenol (EU) and Carvone (CN). Specifically, CL and microwave heating (M) for 45 s showed the most effective inactivation (ca. 6 log reduction) for the pathogens in BPW. Similar trends were shown in hot-chili sauce. However, M + CI inactivation did not show synergistic effects in hot-chili sauce. Microwave heating time for hot-chilis sauce was 40 s. In propidium iodide uptake study, M + CL was found to cause most severe damage to cell membrane (758.5 of PI value for E. coli O157:H7) while M + CU and M + CN had little impact. In DiBAC4(3) test, CL resulted in the largest value (2.09 for E. coli O157:H7). These observations highlight that CL induces synergistic effects as it caused severe membrane damage along with destruction of membrane potential. The combined treatment did not show any significant difference in quality change compared to untreated hot-chili sauce (p > 0.05). The result indicates the potential application of CL and M combination for hot-chili sauce processes to ensure microbiological safety with acceptable quality.

Computational fluid dynamics-based parametric study on the performance of solar air heater channel.

Computational fluid dynamics (CFD) plays a prominent role in the design and development of solar air heaters. The previous investigations have lagged in using a radiation model for the solar heat input; instead, most of the researchers simulated a constant heat flux model. Moreover, an extensive study on the geometrical and boundary conditions like confinement and transition length, suction, and blowing effects has not been studied. The present investigation deals with the aforementioned effects on the flow and heat transfer characteristics of the SAH channel, which is designed for residential space heating. The finite volume-based solver Ansys Fluent is used for finding the field variables. The confinement height is varied from 25 to 150 mm, and the transition length is varied from 250 to 1000 mm. The suction and blowing effect is investigated by changing the flow direction across the channel. Even though the temperature rise is less significant with respect to confinement height and transition length, the effective efficiency increases with decreasing channel height and increasing transition length. In general, blowing of air across the channel gives better performance than suction. When comparing them, the influence is less in temperature rise and more in pressure drop for the channel height of 25 mm, whereas the channel height of 150 mm has better influence in temperature rise and less influence in pressure drop.

Heating Control Strategy Based on Dynamic Programming for Building Energy Saving and Emission Reduction.

Finding the optimal balance between end-user's comfort, lifestyle preferences and the cost of the heating, ventilation and air conditioning (HVAC) system, which requires intelligent decision making and control. This paper proposes a heating control method for HVAC based on dynamic programming. The method first selects the most suitable modeling approach for the controlled building among three machine learning modeling techniques by means of statistical performance metrics, after which the control of the HVAC system is described as a constrained optimization problem, and the action of the controller is given by solving the optimization problem through dynamic programming. In this paper, the variable 'thermal energy storage in building' is introduced to solve the problem that dynamic programming is difficult to obtain the historical state of the building due to the requirement of no aftereffect, while the room temperature and the remaining start hours of the Primary Air Unit are selected to describe the system state through theoretical analysis and trial and error. The results of the TRNSYS/Python co-simulation show that the proposed method can maintain better indoor thermal environment with less energy consumption compared to carefully reviewed expert rules. Compared with expert rule set 'baseline-20 °C', which keeps the room temperature at the minimum comfort level, the proposed control algorithm can save energy and reduce emissions by 35.1% with acceptable comfort violation.

Ohmic heating treatment in high-protein vanilla flavored milk: Quality, processing factors, and biological activity.

The processing of high-protein vanilla-flavored milk was performed under different electric field strengths of ohmic heating (5.22 V/cm, OH6; 6.96 V/cm, OH8; 8.70 V/cm, OH10; 10.43 V/cm, OH12) to evaluate the energy consumption, processing parameters, and microbiological, rheological, and biological aspects, compared with the sample submitted to conventional pasteurization (PAST, 72 °C/15 s). All samples showed higher than 12 g/100 mL of protein, consisting of high-protein content products. In addition, Ohmic Heating (OH) generated lower energy expenditure and more significant microbial inactivation of lactic acid bacteria, molds and yeasts, total mesophiles, and psychotropics. Furthermore, OH at lower electric field strengths, mainly OH8, improved anti-diabetic, anti-oxidant, and anti-hypertensive activities and rheological properties, and resulted in lower hydroxymethylfurfural contents, and higher whey protein nitrogen index. The results suggest that OH is a technology that can be used in flavored milk with high-protein content, being recommended an electric field strength of 6.96 V/cm. However, more studies are necessary to evaluate the effect of OH on high-protein dairy products, mainly by studying other OH processing parameters.

Multi-Degree-of-Freedom Robots Powered and Controlled by Microwaves.

Microwaves have become a promising wireless driving strategy due to the advantages of transmissivity through obstacles, fast energy targeting, and selective heating. Although there are some studies on microwave powered artificial muscles based on different structures, the lack of studies on microwave control has limited the development of microwave-driven (MWD) robots. Here, a far-field MWD parallel robot controlled by adjusting energy distribution via changing the polarization direction of microwaves at 2.47 GHz is first reported. The parallel robot is based on three double-layer bending actuators composed of wave-absorbing sheets and bimetallic sheets, and it can implement circular and triangular path at a distance of 0.4 m under 700 W transmitting power. The thermal response rate of the actuator under microwaves is studied, and it is found that the electric-field components can provide a faster thermal response at the optimal length of actuator than magnetic-field components. The work of the parallel robot is demonstrated in an enclosed space composed of microwave-transparent materials. This developed method demonstrates the multi-degree-of-freedom controllability for robots using microwaves and offers potential solutions for some engineering cases, such as pipeline/reactors inspection and medical applications.

Development of an integrated duty cycle test method to assess cordwood stove performance.

The US Environmental Protection Agency's (EPA's) New Source Performance Standards (NSPS) for Residential Wood Heaters (RWH) require certification emission testing of prototype appliances. In 2015, EPA revised those standards to further reduce particulate matter emissions from this critical source. However, to achieve that goal, lower emissions measured in certification tests must reflect lower emissions when the appliance is operated in homes. Woodstove certification tests have used either the Federal Reference Method (FRM), a crib wood method, or a cordwood testing method developed by ASTM International that was designated as a broadly applicable Alternative Test Method (ATM) by the EPA until December 2021, when that status was revoked. There is broad agreement that the FRM and ASTM procedures do not simulate typical fueling and operating of wood stoves in the field, raising questions about the efficacy of the current program. Effective emission reduction efforts require robust, accurate, and reproducible test methods. With input from a range of stakeholders, the Northeast States for Coordinated Air Use Management (NESCAUM) developed the Integrated Duty Cycle Test Method for Certification of Wood-Fired Stoves Using Cordwood (IDC), a cordwood testing protocol designed to improve the efficacy of residential wood heater certification testing. That method was approved by EPA as a broadly applicable ATM in 2021. IDC test runs assess appliance performance under a range of operating and fueling conditions representative of typical consumer use patterns. Unlike previous test methods, the IDC protocol requires three replicate runs to assess appliance performance variability. Including variable fueling and operating conditions, along with the requirement for replicates runs, will increase the effectiveness of certification testing and promote the development of improved wood stove technology. This paper reports on experiments conducted to develop and test the IDC method.Implications: Residential wood heating is one of the largest sources of primary particulate matter pollution nationwide. EPA's New Source Performance Standards (NSPS) establish emission limits for this source category and require certification testing of prototype wood appliances to demonstrate compliance with those limits. However, the operating and fueling requirements in NSPS compliance testing protocols do not represent typical conditions in the field. We developed a new testing approach, the Integrated-Duty Cycle (IDC) Test Method, to address the shortcomings of current certification test approaches. The IDC procedure for cordwood stoves, which was approved by EPA as a broadly applicable alternative test method in 2021, assesses appliance operations over various operating and fueling conditions representing typical consumer use patterns in an integrated run and requires three replicate runs to enable the assessment of variability in stove performance. Stoves certified with this method will be equipped to meet the NSPS limits consistently in field operation.

Radio frequency pasteurization and heating uniformity of canned pineapple.

This research investigated heating uniformity and pasteurization of canned pineapple using radio frequency (RF) energy. Experiments were conducted in a 6 kW, 27.12 MHz pilot-scale RF system. Results showed that the temperature difference was more than 16°C, and the standard deviation was 4.38°C at the end of heating when using RF heating alone. Water bath-assisted RF (WRF) heating effectively improved the heating uniformity, the temperature difference was less than 7°C and the standard deviation was 2.52°C at the end of heating in the condition of electrode gap (210 mm), chord length of the fruit block (26 mm), and the initial temperature of sugar solution (80°C). When the total number of colonies reached 4-log reduction, water bath (WB) heating alone needed 660 s, and WRF heating needed 180 s. Vitamin C, hardness, and color of fruit blocks were well preserved using WRF heating compared with WB alone. PRACTICAL APPLICATION: This study shows that the pasteurization of canned food by radio frequency heating can achieve better food quality than the traditional pasteurization methods. Therefore, this research can promote the application of radio frequency heating technology in canned food pasteurization.

Impact of parylene coating on heating performance of intravenous fluid warmer: a bench study.

BACKGROUND: Perioperative hypothermia is a common occurrence, particularly with the elderly and pediatric age groups. Hypothermia is associated with an increased risk of perioperative complications. One method of preventing hypothermia is warming the infused fluids given during surgery. The enFlow™ intravenous fluid warmer has recently been reintroduced with a parylene coating on its heating blocks. In this paper, we evaluated the impact of the parylene coating on the new enFlow's fluid warming capacity. METHODS: Six coated and six uncoated enFlow cartridges were used. A solution of 10% propylene glycol and 90% distilled H2O was infused into each heating cartridge at flow rates of 2, 10, 50, 150, and 200 ml/min. The infused fluid temperature was set at 4 °C, 20 °C, and 37 °C. Output temperature was recorded at each level. Data for analysis was derived from 18 runs at each flow rate (six cartridges at three temperatures). RESULTS: The parylene coated fluid warming cartridge delivered very stable output of 40 °C temperatures at flow rates of 2, 10, and 50 ml/min regardless of the temperature of the infusate. At higher flow rates, the cartridges were not able to achieve the target temperature with the colder fluid. Both cartridges performed with similar efficacy across all flow rates at all temperatures. CONCLUSIONS: At low flow rates, the parylene coated enFlow cartridges was comparable to the original uncoated cartridges. At higher flow rates, the coated and uncoated cartridges were not able to achieve the target temperature. The parylene coating on the aluminum heating blocks of the new enFlow intravenous fluid warmer does not negatively affect its performance compared to the uncoated model.

Fast microwave heating-based one-step synthesis of DNA and RNA modified gold nanoparticles.

DNA/RNA-gold nanoparticle (DNA/RNA-AuNP) nanoprobes have been widely employed for nanobiotechnology applications. Here, we discover that both thiolated and non-thiolated DNA/RNA can be efficiently attached to AuNPs to achieve high-stable spherical nucleic acid (SNA) within minutes under a domestic microwave (MW)-assisted heating-dry circumstance. Further studies show that for non-thiolated DNA/RNA the conjugation is poly (T/U) tag dependent. Spectroscopy, test strip hybridization, and loading counting experiments indicate that low-affinity poly (T/U) tag mediates the formation of a standing-up conformation, which is distributed in the outer layer of SNA structure. In further application studies, CRISPR/Cas9-sgRNA (136 bp), SARS-CoV-2 RNA fragment (1278 bp), and rolling circle amplification (RCA) DNA products (over 1000 bp) can be successfully attached on AuNPs, which overcomes the routine methods in long-chain nucleic acid-AuNP conjugation, exhibiting great promise in biosensing and nucleic acids delivery applications. Current heating-dry strategy has improved traditional DNA/RNA-AuNP conjugation methods in simplicity, rapidity, cost, and universality.

Inactivation of Salmonella enterica Serovar Typhimurium and Staphylococcus aureus in Rice by Radio Frequency Heating.

ABSTRACT: The objectives of this study were to determine the effect of the milling degree (MD) of rice (Oryza sativa L.) on the heating rate, pathogen inactivation (Salmonella Typhimurium and Staphylococcus aureus), and color change resulting from radio frequency (RF) heating. Rice samples inoculated with pathogens were placed in a polypropylene jar and subjected to RF heating for 0 to 75 s. The heating rate of rice with a 2% MD was the highest during RF heating, followed by those with a 0, 8, and 10% MD; the reduction of pathogens showed the same trend. The reductions of pathogen levels in rice with MDs of 0 and 2% were significantly higher than those observed for rice with MDs of 8 and 10% under the same treatment conditions. For example, log reductions of Salmonella Typhimurium in rice by 55-s RF heating were 3.64, 5.19, 2.18, and 1.80 for MDs of 0, 2, 8, and 10%, respectively. At the same treatment conditions, log reductions of S. aureus were 2.77, 5.08, 1.15, and 0.90 for MDs of 0, 2, 8, and 10%, respectively. The color of rice measured according to L*, a*, and b* was not significantly altered after RF heating, regardless of the MD. Therefore, the MD of rice should be considered before RF heating is applied to inactivate foodborne pathogens.

Investigating the Health Effects of 3 Coexisting Tobacco-Related Products Using System Dynamics Population Modeling: An Italian Population Case Study.

With the proliferation of tobacco products, there might be a need for more complex models than current two-product models. We have developed a three-product model able to represent interactions between three products in the marketplace. We also investigate if using several implementations of two-product models could provide sufficient information to assess 3 coexisting products. Italy is used as case-study with THPs and e-cigarettes as the products under investigation. We use transitions rates estimated for THPs in Japan and e-cigarettes in the USA to project what could happen if the Italian population were to behave as the Japanese for THP or USA for e-cigarettes. Results suggest that three-product models may be hindered by data availability while two product models could miss potential synergies between products. Both, THP and E-Cigarette scenarios, led to reduction in life-years lost although the Japanese THP scenario reductions were 3 times larger than the USA e-cigarette projections.

Serum and plasma brain-derived neurotrophic factor concentration are elevated by systemic but not local passive heating.

Brain-derived neurotrophic factor (BDNF) plays a key role in neuronal adaptations. While previous studies suggest that whole-body heating can elevate circulating BDNF concentration, this is not known for local heating protocols. This study investigated the acute effects of whole-body versus local passive heating on serum and plasma BDNF concentration. Using a water-perfused suit, ten recreationally active males underwent three 90 min experimental protocols: heating of the legs with upper-body cooling (LBH), whole-body heating (WBH) and a control condition (CON). Blood samples were collected before, immediately after and 1 h post-heating for the determination of serum and plasma BDNF concentration, platelet count as well as the BDNF release per platelet. Rectal temperature, cardiac output and femoral artery shear rate were assessed at regular intervals. Serum and plasma BDNF concentration were elevated after WBH (serum: 19.1±5.0 to 25.9±11.3 ng/ml, plasma: 2.74±0.9 to 4.58±2.0; p<0.044), but not LBH (serum: 19.1±4.7 to 22.3±4.8 ng/ml, plasma: 3.25±1.13 to 3.39±0.90 ng/ml; p>0.126), when compared with CON (serum: 18.6±6.4 to 16.8±3.4 ng/ml, plasma: 2.49±0.69 to 2.82±0.89 ng/ml); accompanied by an increase in platelet count (p<0.001). However, there was no change in BDNF content per platelet after either condition (p = 0.392). All physiological measures were elevated to a larger extent after WBH compared with LBH (p<0.001), while shear rate and rectal temperature were higher during LBH than CON (p<0.038). In conclusion, WBH but not LBH acutely elevates circulating BDNF concentration. While these findings further support the use of passive heating to elevate BDNF concentration, a larger increase in shear rate, sympathetic activity and/or rectal temperature than found after LBH appears needed to induce an acute BDNF response by passive heating.

Eficacia y seguridad de hipotermia terapéutica de cuerpo completo con mantas térmicas en recien nacidos de 35 semanas o más con asfixia perinatal y encefalopatía hipóxico-isquémica moderada o severa / Efficacy and safety of whole body therapeutic hypothermia with heating blankets in newborns 35 weeks or older with perinatal asphyxia and moderate or severe hypoxic-ischemic encephalopathy

INTRODUCCIÓN: El presente documento de evaluación de tecnología sanitaria (ETS) expone la evaluación de la eficacia y seguridad del equipo de hipotermia terapéutica de cuerpo completo (HTCC) con mantas térmicas en comparación al tratamiento de soporte estándar en la unidad de cuidados intensivos neonatales (UCIN) en recién nacidos de 35 semanas o más con asfixia perinatal (AP) y encefalopatía hipóxico-isquémica (EHI) moderada o severa sin malformaciones congénitas mayores, cromosomopatías incompatibles con la vida, retardo en crecimiento intrauterino severo (<1,8 kg), patologías quirúrgicas severas, o con criterios de severidad (bradicardia mantenida, midriasis paralítica, ausencia de reflejo corneal). La encefalopatía neonatal es un estado de alteración de la función neurológica del recién nacido. Esta patología se asocia a convulsiones y dificultad para iniciar o mantener la respiración; acarreando una alta morbilidad y mortalidad neonatal. La encefalopatía hipóxico-isquémica (EHI), producida por un cuadro de asfixia perinatal (AP), es uno de los principales subtipos de encefalopatía neonatal. En el Perú, un informe de la Dirección de Epidemiología del Ministerio de Salud reportó que la AP fue la tercera causa de muerte neonatal entre los años 2011 y 2012. Además, reportes del servicio de neonatología del Hospital Nacional Edgardo Rebagliati Martins (HNERM) del periodo 2015 - 2016 estimaron la incidencia de EHI en 2.5 casos por cada 1000 nacidos vivos. Diversos estudios han reportado que la neuroprotección mediante la hipotermia terapéutica (HT) disminuye la morbilidad y mortalidad en neonatos con EHI moderada o severa. Para la inducción de HT se utilizan, principalmente, dos tecnologías: 1) la HT de cuerpo completo (HTCC) y 2) la HT selectiva de cabeza (HTSC). Las unidades de cuidados intensivos neonatales (UCIN) de EsSalud brindan terapia de soporte a los recién nacidos con EHI consistente en monitoreo de signos vitales y atención oportuna frente a disfunciones orgánicas, además de reducción de la temperatura mediante el apagado de calefactor en la incubadora, pero no cuentan con equipos específicos que aseguren que el neonato alcance temperaturas de enfriamiento óptimas. Por ello, los especialistas en neonatología del HNERM solicitan la incorporación de la tecnología de HTCC con mantas térmicas con la finalidad de disminuir la mortalidad y discapacidad severa de los neonatos con EHI moderada o severa. En este sentido, el objetivo del presente dictamen preliminar fue evaluar la eficacia y seguridad de la hipotermia terapéutica de cuerpo completo con mantas térmicas en recién nacidos de 35 semanas o más con asfixia perinatal y encefalopatía hipóxico-isquémica moderada o severa. METODOLOGÍA: Se realizó una búsqueda sistemática para identificar la evidencia disponible a abril de 2021 sobre la eficacia y seguridad del procedimiento de hipotermia terapéutica de cuerpo completo en recién nacidos de 35 semanas o más con asfixia neonatal y encefalopatía hipóxico-isquémica moderada o severa. Se indagó en las bases de datos PubMed, Cochrane Library y LILACS (Literatura Latinoamericana y del Caribe en Ciencias de la Salud) y se creó una alerta semanas en PubMed que informara si surgiera nueva evidencia sobre el tema. Adicionalmente, se realizó una búsqueda manual de literatura gris mediante el motor de búsqueda Google. Se buscaron GPC y ETS que pudieran haber sido omitidas en la revisión sistemática por no encontrarse indixadas en las bases de datos consultadas. De igual forma, se consultaron las páginas oficiales de grupos conocidos por realizar ETS y GPC que incluyó el National Institute for Health and Care Excellence (NICE), la Canadian Agency for Drugs and Technologies in Health (CADTH), la Haute Autorité de Santé (HAS), el Institut für Qualitát und Wirtschaftlichkeit im Gesundheitswesen (IQWiG) y la Base Regional de Informes de Evaluación de Tecnologías en Salud de las Américas (BRISA), además de sociedades especializadas en manejo de pacientes pediátricos con patologías perinatales (sociedad británica de medicina perinatal (BAPM), la asociación americana del corazón, y la sociedad canadiense de pediatría). RESULTADOS: La presente sinopsis describe la evidencia disponible sobre la eficacia y seguridad de la HTCC con mantas térmicas en recién nacidos de 35 semanas o más con AP y EHI moderada o severa, según el tipo de publicación. CONCLUSIONES: El objetivo del presente dictamen preliminar es evaluar la eficacia y seguridad de la hipotermia terapéutica de cuerpo completo con mantas térmicas en recién nacidos de 35 semanas o más de gestación, con asfixia perinatal y encefalopatía hipóxico-isquémica moderada o severa. Se identificaron seis GPC American Heart Association (AHA), 2020; Ministerio de Salud Pública del Ecuador (MSP), 2019; Canadian Paediatric Society (CPS), 2018; Instituto Mexicano del Seguro Social (IMSS), 2017; Ministerio de Sanidad, Servicio Social e Igualdad de España (MSSSI), 2015; y Ministerio de Salud y Protección Social de Colombia (MinSalud), 2013) y siete publicaciones de cuatro ensayos clínicos aleatorizados (ECA) (HELIX: Thayyil et al., 2021; TOBY: Azzopardi et al., 2014, 2009; NICHD: Shankaran et al., 2012, 2008, 2005; y neo.nEURO.network: Simbruner et al., 2010). No existe evidencia de una mayor eficacia en el uso de HTCC frente a la HTSC. Pese a ello, en centros asistenciales que no han implementado aún un método de HT, las recomendaciones de las GPC indican que debería implementarse equipos de HTCC debido a su facilidad de uso, menor costo y facilidad de acceso para la utilización de otros equipos como el electroencefalograma. Entre las GPC, existe un consenso en que la aplicación de HTCC debe realizarse bajo protocolos similares a los utilizados en los principales ECA. La eficacia de la HTCC con mantas térmicas en infantes de 36 semanas o más de gestación con EIH moderada a severa es consistente en cuanto a la reducción de morbilidad, pero no en mortalidad. Los ECA más grandes en el tema han reportado beneficios clínicos, tanto en indicadores de desarrollo mental y psicomotor, como en ocurrencia de parálisis cerebral a los 18 - 22 meses y 6 - 7 años de vida. Pese a que uno de los ECA evaluados (HELIX) reporta mayor riesgo de muerte y ocurrencia de eventos adversos en los pacientes intervenidos con HTCC, esto se puede explicar debido a factores poblacionales que modificaron el efecto de la intervención. Por lo expuesto, el IETSI aprueba el uso de equipos de HTCC con mantas térmicas en recién nacidos de 36 semanas o más de edad gestacional, con AP y EHI moderada o severa, según lo establecido en el Anexo N°1. Debido a la falta de evidencia, no se aprueba su uso en recién nacidos con menos de 36 semanas de edad gestacional. La vigencia del presente dictamen preliminar es de un año a partir de la fecha de publicación.