RESUMO
Electrocaloric1,2 and electrostrictive3,4 effects concurrently exist in dielectric materials. Combining these two effects could achieve the lightweight, compact localized thermal management that is promised by electrocaloric refrigeration5. Despite a handful of numerical models and schematic presentations6,7, current electrocaloric refrigerators still rely on external accessories to drive the working bodies8-10 and hence result in a low device-level cooling power density and coefficient of performance (COP). Here we report an electrocaloric thin-film device that uses the electro-thermomechanical synergy provided by polymeric ferroelectrics. Under one-time a.c. electric stimulation, the device is thermally and mechanically cycled by the working body itself, resulting in an external-driver-free, self-cycling, soft refrigerator. The prototype offers a directly measured cooling power density of 6.5 W g-1 and a peak COP exceeding 58 under a zero temperature span. Being merely a 30-µm-thick polymer film, the device achieved a COP close to 24 under a 4 K temperature span in an open ambient environment (32% thermodynamic efficiency). Compared with passive cooling, the thin-film refrigerator could immediately induce an additional 17.5 K temperature drop against an electronic chip. The soft, polymeric refrigerator can sense, actuate and pump heat to provide automatic localized thermal management.
Assuntos
Polímeros , Refrigeração , Termodinâmica , Refrigeração/instrumentação , Polímeros/química , Temperatura Baixa , Eletricidade , Desenho de Equipamento , Estimulação Elétrica , TemperaturaAssuntos
Criopreservação , Congelamento , Refrigeração , Gerenciamento do Tempo , Criopreservação/economia , Criopreservação/instrumentação , Criopreservação/métodos , Refrigeração/economia , Refrigeração/instrumentação , Refrigeração/métodos , Gerenciamento do Tempo/economia , Gerenciamento do Tempo/métodosRESUMO
Diabetes prevalence within the global population has nearly doubled since 1980, with the most rapid growth occurring in low- and middle-income countries. Diabetes management in resource-limited settings such as Haiti presents many challenges, including the storage of insulin. Despite a lack of published data on insulin thermostability, storage at 2-8°C or at room temperature (25°C) is recommended. In Haiti, access to refrigeration and thereby proper insulin storage is severely limited. Commercial storage devices such as the FRIO cooling wallet are cost-prohibitive and not available locally, and alternatives such as small clay pots are fragile and nonportable. Here, we designed and tested the cooling efficacy of a homemade wallet made of acrylate polymer beads and a hand-sewn cotton pouch compared to a FRIO wallet and a clay pot. All studies were conducted over a ten-day period at the Kay Mackenson Clinic in Montrouis, Haiti. Temperature and humidity values were continuously collected using wireless monitors placed inside each device, and hourly ambient temperature and humidity values were manually recorded. Evaporative cooling efficacy was calculated using collected data. The homemade wallet and FRIO cooling wallet demonstrated comparable cooling efficacy with an average of 71% and 73%, respectively. The clay pot demonstrated significantly decreased efficacy with an average of 27% (p < 0.05). The homemade insulin wallet is a promising alternative for the storage of insulin in low-resource settings without the financial and physical barriers of commercial and locally sourced devices. Additionally, this wallet could be readily adapted for the storage of other perishable medical supplies in low-income countries.
Assuntos
Insulina , Refrigeração/instrumentação , Água/fisiologia , Temperatura Baixa , Armazenamento de Medicamentos/métodos , Desenho de Equipamento , Haiti , Humanos , Umidade , Insulina/uso terapêutico , Microesferas , Refrigeração/métodos , Temperatura , Água/químicaRESUMO
BACKGROUND: Cryopreserved platelets show a reduced recovery and viability after freezing and thawing including several ultrastructural and phenotypic deteriorations compared with liquid-stored platelets. It is suggested that using Controlled-Rate Freezing (CRF) can reduce variability and optimize the functionality profile for cells. The objective of the study is to compare cellular, metabolic, phenotypic and functional effects on platelets after cryopreservation using different freezing rate protocols. STUDY DESIGN AND METHODS: To evaluate the possible effects of different freezing rate protocols a two-experimental study comparing diverse combinations was tested with a pool and split design. Uncontrolled freezing of platelets in materials with different thermal conductivity (metal vs cardboard) was evaluated in experiment 1. Experiment 2 evaluated uncontrolled vs a controlled-rate freezing protocol in metal boxes. All variables were assessed pre and post cryopreservation. RESULTS: Directly after thawing, no major differences in platelet recovery, LDH, ATP, Δψ, CD62P, CD42b, platelet endothelial cell adhesion molecule and sCD40L were seen between units frozen with different thermal conductivity for temperature. In contrast, we observed signs of increased activation after freezing using the CRF protocol, reflected by increased cell surface expression of CD62P, PAC-1 binding and increased concentration of LDH. Agonist induced expression of a conformational epitope on the GPIIb/IIIa complex and contribution to blood coagulation in an experimental rotational thromboelastometry setup were not statistically different between the groups. CONCLUSION: The use of a uncontrolled freezing rate protocol is feasible, creating a platelet product comparable to using a controlled rate freezing equipment during cryopreservation of platelets.
Assuntos
Buffy Coat/citologia , Plaquetas , Preservação de Sangue/métodos , Criopreservação/métodos , Difosfato de Adenosina/farmacologia , Coagulação Sanguínea , Plaquetas/química , Plaquetas/citologia , Plaquetas/fisiologia , Ligante de CD40/farmacologia , Separação Celular , Sobrevivência Celular , Centrifugação , Colágeno/farmacologia , Criopreservação/instrumentação , Dimetil Sulfóxido , Humanos , Fatores Imunológicos/farmacologia , Ativação Plaquetária/efeitos dos fármacos , Refrigeração/instrumentação , Condutividade Térmica , TromboelastografiaRESUMO
Objetivo: Descrever a adequação da conservação de imunobiológicos nas salas de imunização dos municípios da macrorregião de saúde Oeste do estado de Minas Gerais, Brasil. Métodos: Estudo descritivo, pautado em uma escala validada, com escore máximo de 15 pontos. Realizou-se análise descritiva e teste de associação entre os escores obtidos pelos municípios e variáveis do contexto externo. Resultados: Foram avaliadas 275 do total de 295 salas de imunização existentes. A conservação de imunobiológicos na macrorregião Oeste obteve um escore médio de 4 pontos (escore-padrão de 0 a 15). Evidenciou-se ausência ou carência de insumos destinados à conservação de imunobiológicos, e processos de trabalho que requerem aprimoramento. Municípios de pequeno porte apresentaram melhor conservação de imunobiológicos (p=0,011). Conclusão: A conservação de imunobiológicos nas salas de imunização da macrorregião de saúde Oeste de Minas Gerais foi considerada inadequada.
Objetivo: Describir la adecuación de la conservación de inmunobiológicos en las salas de inmunización de la macrorregión Oeste de Minas Gerais, Brasil. Métodos: Estudio descriptivo a partir de una escala validada con una puntuación máxima de 15 puntos. Se realizaron análisis descriptivos y pruebas de asociación entre las puntuaciones obtenidas por los municipios y las variables del contexto externo. Resultados: Se evaluaron 275 de un total de 295 salas de vacunación. La conservación de los inmunobiológicos en la macrorregión Oeste obtuvo una puntuación promedio de 4 puntos (4/15). Se evidenció la ausencia o falta de insumos para la conservación de inmunobiológicos y procesos de trabajo que requieren ser mejorados. Los municipios pequeños presentaron una mejor conservación de los inmunobiológicos (p=0,011). Conclusión: La conservación inmunobiológica en las salas de vacunación de la macrorregión Oeste de Minas Gerais fue considerada inadecuada.
Objective: To describe the adequacy of immunobiological agent conservation in vaccination rooms in the municipalities of the Western health macro-region of the state of Minas Gerais, Brazil. Methods: This was a descriptive study, based on a validated scale, with a maximum score of 15 points. A descriptive analysis and an association test between the scores obtained by the municipalities and variables of the external context were performed. Results: 275 out of a total of 295 existing vaccination rooms were evaluated. Immunobiological agent conservation in the West macro-region obtained an average score of 4 points (standard score, 0 to 15). There was a poor availability of immunization supplies aimed at immunobiological agent conservation, and work processes, that require improvement. Small municipalities presented better immunobiological agent conservation (p=0.011). Conclusion: Immunobiological agent conservation in vaccination rooms in the Western health macro-region of Minas Gerais State was considered inadequate.
Assuntos
Humanos , Vacinas/provisão & distribuição , Imunização/instrumentação , Refrigeração/instrumentação , BrasilRESUMO
Vaccine temperature control failures represent a significant public and private healthcare cost. Vaccines damaged by excessive heat or freezing lose their effectiveness, putting public health at risk. Some vaccine administration programs recommend placing water bottles inside domestic refrigerators used for vaccine storage as a thermal ballast, to mitigate temperature excursion risks. However, the effect of variable thermal ballast loading on refrigerator performance has not been thoroughly quantified or documented, and generalized programmatic recommendations are subject to end-user interpretation. Here we show that a thermal ballast load comprising ten to fifteen percent of the total refrigerator storage volume provides a measurable effect on domestic refrigerator temperature stability during power outage events, maintaining vaccine temperatures between 2 °C and 8 °C for 4 to 6 hours without power. Thermal ballast usage does not reliably reduce the frequency or severity of temperature excursions caused by repeated door opening, accidental "door left open" events, or refrigerator defrost cycle activation. Use of a moderate thermal ballast load is a practical strategy for mitigating temperature excursions risks in areas with frequent or protracted power outages, but the practice has limited benefit in other adverse scenarios. Empowering providers to make informed decisions about the use of thermal ballast materials supports better, safer vaccine management.
Assuntos
Armazenamento de Medicamentos , Vacinas/química , Algoritmos , Armazenamento de Medicamentos/métodos , Desenho de Equipamento , Refrigeração/instrumentação , Refrigeração/métodos , TemperaturaRESUMO
INTRODUCTION: World Health Organisation (WHO) recommends that countries conduct comprehensive national immunisation programme reviews regularly to help them identify systems wide-barriers or gaps and monitor performance against the set targets. METHODS: we reviewed reports from the latest national immunisation program reviews conducted in the 20 countries in the subregion in the course of 2012-2018. We generated descriptive analysis of the findings across the subregion. RESULTS: the 20 program reviews included field observations to the subnational levels as well as interviews with program staff and stakeholders. At the time of the reviews, only 11 countries had functional National Immunisation Technical Advisory Groups. Operational funding was inadequate in half of the countries. The reviews documented the cancellation of outreach services, supportive supervision visits and maintenance of cold chain equipment due to the lack of fuel or operational funding. Immunisation programs in 10 countries had major human resource gaps. Vaccine stock management tools were not effectively used in 10 countries, and stockout of vaccines and supplies was documented in 9 countries during the review. The full components of the Reaching Every District (RED) Strategy were implemented in only 3 of the 20 countries. Twelve countries reported challenges with the availability and accuracy of target populations. Four countries had documented the presence of vaccine hesitant groups at the time of the reviews. CONCLUSION: the reviews demonstrated challenges in various aspects of the programs in different countries. The implementation of the review recommendations should be built into the annual program plans, as well as into costed multi-year plans, in order to address the gaps and helps the program to attain the set targets. With the rapid evolution of the scope and complexity of the immunisation programs in recent years, countries should invest their efforts in building the capacity of their human resources as well as updating their logistics and data systems.
Assuntos
Programas de Imunização/organização & administração , Imunização , Vacinas/administração & dosagem , África Oriental , África Austral , Fortalecimento Institucional , Estudos Transversais , Humanos , Desenvolvimento de Programas , Refrigeração/instrumentação , Recusa de Vacinação/estatística & dados numéricos , Vacinas/provisão & distribuição , Recursos Humanos/estatística & dados numéricos , Organização Mundial da SaúdeRESUMO
BACKGROUND: This work aimed to compare raw fresh meat (minced bovine and pork in pieces) preserved by hyperbaric storage (HS) at room-like temperature (75 MPa/25 °C) and HS at cold temperatures (60 MPa/10 °C) for up to 60 days, being both compared to refrigeration (RF, 4 °C). RESULTS: HS conditions showed microbial load reductions over 60 days of storage, leading to a possible shelf-life extension when compared to samples at RF. Moreover, between both HS conditions similar results were found at the 60th day, reaching in some cases values < 1.00 log CFU g-1 . Overall, pH presented an increase with storage for both HS conditions (e.g. over 30 days, from 5.51 ± 0.02 to 5.70 ± 0.01 and 5.85 ± 0.03, for 60 MPa/10 °C and 75 MPa/25 °C, respectively, on pork meat in pieces, PP) contrary to RF where pH values decreased (from 5.51 ± 0.02 to 5.33 ± 0.03). Regarding moisture content and drip loss, lower and higher values were found, respectively at 75 MPa/25 °C, mainly in bovine minced meat. Overall, colour ΔE* did not present considerable differences for both samples under all storage conditions. Lipid oxidation presented an increase tendency over time, with both HS conditions showing the higher values (1.795 ± 0.217 and 2.169 ± 0.117 for 60 MPa/10 °C and 75 MPa/25 °C, respectively, compared to 0.895 ± 0.084 µg MDA g-1 in PP samples at the 30th day). CONCLUSION: Although several advantages were found further studies should be carried out in order to optimize the HS conditions for raw fresh meat and assess the impact of this preservation methodology on other meat quality parameters as for instance sensorial aspects. © 2019 Society of Chemical Industry.
Assuntos
Conservação de Alimentos/métodos , Carne/análise , Refrigeração/métodos , Animais , Bovinos , Temperatura Baixa , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos , Lipídeos/química , Oxirredução , Refrigeração/instrumentação , SuínosRESUMO
RESEARCH QUESTION: Assisted reproduction laboratories record instrument performance periodically. No standardized guidelines have been produced for this activity despite mandatory auditing systems in several countries. This study of 36 laboratories in 12 different countries was conducted to assess differences and similarities between quality assurance programmes using an adaptable cloud-based quality-control app for instrument monitoring. DESIGN: A total of 36 deidentified IVF laboratories that subscribed to the same quality-assurance application were studied. Data were evaluated based on instrument types allocated to 10 domains: incubators, gas tanks, warming surfaces, refrigerators and freezers, cryo-storage, environment, water purification, peripheral equipment, checklists and miscellaneous. RESULTS: The incubator domain constituted the greatest proportion of parameters (35%), followed by surface warming instruments at 15%. Most incubator O2 readings were monitored between 4.5 and 5.5%, and between 5.5 and 6.5% for CO2. The altitude of the laboratory was poorly correlated with the CO2 setting. Incubator display and measured values of gases and temperature by built-in sensors vary considerably compared with third-party sensors. A quality-control diligence score or mean average data points was calculated for each laboratory. This score is independent of number of instruments or laboratory size. Higher scores were associated with laboratories in countries with government regulations and mandatory auditing systems. CONCLUSIONS: Major differences exist in instrument monitoring practices among laboratories. Although incubator monitoring is the largest domain, many other sensitive instruments are diligently monitored by most laboratories. International standardization and guidelines are needed.
Assuntos
Planejamento Ambiental , Laboratórios , Controle de Qualidade , Técnicas de Reprodução Assistida/instrumentação , Técnicas de Reprodução Assistida/normas , Planejamento Ambiental/normas , Análise de Falha de Equipamento , Feminino , Fertilização in vitro/instrumentação , Fertilização in vitro/normas , Humanos , Incubadoras/normas , Laboratórios/organização & administração , Laboratórios/normas , Ensaio de Proficiência Laboratorial/métodos , Masculino , Gravidez , Garantia da Qualidade dos Cuidados de Saúde/métodos , Garantia da Qualidade dos Cuidados de Saúde/normas , Refrigeração/instrumentação , Refrigeração/normasRESUMO
BACKGROUND: Kidney transplantation is the optimal treatment for end-stage kidney disease. Retrieval, transport and transplant of kidney grafts causes ischaemia reperfusion injury. The current accepted standard is static cold storage (SCS) whereby the kidney is stored on ice after removal from the donor and then removed from the ice box at the time of implantation. However, technology is now available to perfuse or "pump" the kidney during the transport phase or at the recipient centre. This can be done at a variety of temperatures and using different perfusates. The effectiveness of treatment is manifest clinically as delayed graft function (DGF), whereby the kidney fails to produce urine immediately after transplant. OBJECTIVES: To compare hypothermic machine perfusion (HMP) and (sub)normothermic machine perfusion (NMP) with standard SCS. SEARCH METHODS: We searched the Cochrane Kidney and Transplant Register of Studies to 18 October 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. SELECTION CRITERIA: All randomised controlled trials (RCTs) and quasi-RCTs comparing HMP/NMP versus SCS for deceased donor kidney transplantation were eligible for inclusion. All donor types were included (donor after circulatory (DCD) and brainstem death (DBD), standard and extended/expanded criteria donors). Both paired and unpaired studies were eligible for inclusion. DATA COLLECTION AND ANALYSIS: The results of the literature search were screened and a standard data extraction form was used to collect data. Both of these steps were performed by two independent authors. Dichotomous outcome results were expressed as risk ratio (RR) with 95% confidence intervals (CI). Continuous scales of measurement were expressed as a mean difference (MD). Random effects models were used for data analysis. The primary outcome was incidence of DGF. Secondary outcomes included: one-year graft survival, incidence of primary non-function (PNF), DGF duration, long term graft survival, economic implications, graft function, patient survival and incidence of acute rejection. MAIN RESULTS: No studies reported on NMP, however one ongoing study was identified.Sixteen studies (2266 participants) comparing HMP with SCS were included; 15 studies could be meta-analysed. Fourteen studies reported on requirement for dialysis in the first week post-transplant (DGF incidence); there is high-certainty evidence that HMP reduces the risk of DGF when compared to SCS (RR 0.77; 95% CI 0.67 to 0.90; P = 0.0006). HMP reduces the risk of DGF in kidneys from DCD donors (7 studies, 772 participants: RR 0.75; 95% CI 0.64 to 0.87; P = 0.0002; high certainty evidence), as well as kidneys from DBD donors (4 studies, 971 participants: RR 0.78, 95% CI 0.65 to 0.93; P = 0.006; high certainty evidence). The number of perfusions required to prevent one episode of DGF (number needed to treat, NNT) was 7.26 and 13.60 in DCD and DBD kidneys respectively. Studies performed in the last decade all used the LifePort machine and confirmed that HMP reduces the incidence of DGF in the modern era (5 studies, 1355 participants: RR 0.77, 95% CI 0.66 to 0.91; P = 0.002; high certainty evidence). Reports of economic analysis suggest that HMP can lead to cost savings in both the North American and European settings.Two studies reported HMP also improves graft survival however we were not able to meta-analyse these results. A reduction in incidence of PNF could not be demonstrated. The effect of HMP on our other outcomes (incidence of acute rejection, patient survival, hospital stay, long-term graft function, duration of DGF) remains uncertain. AUTHORS' CONCLUSIONS: HMP is superior to SCS in deceased donor kidney transplantation. This is true for both DBD and DCD kidneys, and remains true in the modern era (studies performed in the last decade). As kidneys from DCD donors have a higher overall DGF rate, fewer perfusions are needed to prevent one episode of DGF (7.26 versus 13.60 in DBD kidneys).Further studies looking solely at the impact of HMP on DGF incidence are not required. Follow-up reports detailing long-term graft survival from participants of the studies already included in this review would be an efficient way to generate further long-term graft survival data.Economic analysis, based on the results of this review, would help cement HMP as the standard preservation method in deceased donor kidney transplantation.RCTs investigating (sub)NMP are required.
Assuntos
Rim , Preservação de Órgãos/métodos , Perfusão/métodos , Refrigeração/métodos , Doadores de Tecidos , Função Retardada do Enxerto , Rejeição de Enxerto/epidemiologia , Sobrevivência de Enxerto , Humanos , Incidência , Transplante de Rim/mortalidade , Preservação de Órgãos/instrumentação , Perfusão/instrumentação , Ensaios Clínicos Controlados Aleatórios como Assunto , Refrigeração/instrumentação , Fatores de TempoRESUMO
This study presents a quantification of the financial needs to maintain the stock of cold equipment for the preservation of medical products in public health care establishments of European Union (EU) countries. The conditions that must be guaranteed, the types of equipment used, the installed capacity, the total annual financial needs and the estimate of its evolution in the near future are addressed. A field survey involving Portuguese establishments of various types and dimensions was performed in order to assess the currently installed volume by type of equipment. Through an analysis based on possible scenarios and using a methodology considered adequate, the financial needs to maintain such equipment in operation was estimated for Portugal, for each EU country and for the EU as a whole. The economic value of these amounts in 2017 and following years was obtained assuming the average price of each type of equipment and considering an expected evolution of its value.
Assuntos
Custos e Análise de Custo , Armazenamento de Medicamentos/normas , Equipamentos e Provisões/provisão & distribuição , Saúde Pública , Refrigeração/normas , Vacinas/provisão & distribuição , União Europeia , Organização do Financiamento , Setor de Assistência à Saúde , Instalações de Saúde , Humanos , Portugal , Refrigeração/instrumentaçãoRESUMO
After the 2010 earthquake, Haiti committed to introducing 4 new antigens into its routine immunization schedule, which required improving its cold chain (ie, temperature-controlled supply chain) and increasing vaccine storage capacity by installing new refrigerators. We tested the feasibility of using remote temperature monitoring devices (RTMDs) in Haiti in a sample of vaccine refrigerators fueled by solar panels, propane gas, or electricity. We analyzed data from 16 RTMDs monitoring 24 refrigerators in 15 sites from March through August 2014. Although 5 of the 16 RTMDs exhibited intermittent data gaps, we identified typical temperature patterns consistent with refrigerator door opening and closing, propane depletion, thermostat insufficiency, and overstocking. Actual start-up, annual maintenance, and annual electricity costs for using RTMDs were $686, $179, and $9 per refrigerator, respectively. In Haiti, RTMD use was feasible. RTMDs could be prioritized for use with existing refrigerators with high volumes of vaccines and new refrigerators to certify their functionality before use. Vaccine vial monitors could provide additional useful information about cumulative heat exposure and possible vaccine denaturation.
Assuntos
Armazenamento de Medicamentos/métodos , Refrigeração/instrumentação , Tecnologia de Sensoriamento Remoto/instrumentação , Vacinas , Temperatura Baixa , Custos e Análise de Custo , Armazenamento de Medicamentos/economia , Haiti , Humanos , Refrigeração/economia , Refrigeração/métodos , Tecnologia de Sensoriamento Remoto/economia , Tecnologia de Sensoriamento Remoto/métodosRESUMO
The evolution of different quality parameters (firmness, weight loss, colour changes, microbial counts, consumer rejection) of packed fresh-cut Iceberg salad was assessed at 4, 8 and 12°C to simulate domestic refrigerators running at different conditions. The increase in storage temperature did not affect salad firmness and weight loss but increased colour changes, microbial growth and consumer rejection. A survey among Italian consumers was also carried out and demonstrated that fresh-cut salad was mainly consumed within the first 5days after purchasing. Consumer rejection data were combined with data relevant to the distribution of salad consumption over the days following product purchase, to estimate salad wasting risk. When salad was stored at 4 and 8°C, estimated wasted packages within the expiration date (7days) were <1%. By contrast, 13% of the packages was estimated to be wasted within 7days of storage at 12°C. Quantification of wasting risk is a necessary information to identify efficient and sustainable interventions to tackle food waste.
Assuntos
Temperatura Baixa , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos/instrumentação , Utensílios Domésticos , Lactuca , Refrigeração/instrumentação , Desenho de Equipamento , Embalagem de Alimentos , Conservação de Alimentos/métodos , Armazenamento de Alimentos/métodos , Refrigeração/métodos , Fatores de TempoRESUMO
In the framework of food safety, when mimicking the consumer phase, the storage time and temperature used are mainly considered as single point estimates instead of probability distributions. This singlepoint approach does not take into account the variability within a population and could lead to an overestimation of the parameters. Therefore, the aim of this study was to analyse data on domestic refrigerator temperatures and storage times of chilled food in European countries in order to draw general rules which could be used either in shelf-life testing or risk assessment. In relation to domestic refrigerator temperatures, 15 studies provided pertinent data. Twelve studies presented normal distributions, according to the authors or from the data fitted into distributions. Analysis of temperature distributions revealed that the countries were separated into two groups: northern European countries and southern European countries. The overall variability of European domestic refrigerators is described by a normal distribution: N (7.0, 2.7)°C for southern countries, and, N (6.1, 2.8)°C for the northern countries. Concerning storage times, seven papers were pertinent. Analysis indicated that the storage time was likely to end in the first days or weeks (depending on the product use-by-date) after purchase. Data fitting showed the exponential distribution was the most appropriate distribution to describe the time that food spent at consumer's place. The storage time was described by an exponential distribution corresponding to the use-by date period divided by 4. In conclusion, knowing that collecting data is time and money consuming, in the absence of data, and at least for the European market and for refrigerated products, building a domestic refrigerator temperature distribution using a Normal law and a time-to-consumption distribution using an Exponential law would be appropriate.
Assuntos
Temperatura Baixa , Conservação de Alimentos/instrumentação , Inocuidade dos Alimentos , Armazenamento de Alimentos/instrumentação , Utensílios Domésticos , Refrigeração/instrumentação , Qualidade de Produtos para o Consumidor , Desenho de Equipamento , Contaminação de Alimentos/prevenção & controle , Doenças Transmitidas por Alimentos/prevenção & controle , Medição de Risco , Fatores de Risco , Fatores de TempoRESUMO
INTRODUCTION: The vaccine vial monitor (VVM) registers cumulative heat exposure on vaccines over time. As low- and lower-middle-income countries transition beyond support from the Global Alliance for Vaccines and Immunization (Gavi), they will assume full responsibility for vaccine financing and procurement. It is unclear to what extent countries transitioning out of Gavi support will continue to include VVMs on their vaccines. This paper aims to systematically review evidence on VVM availability and use in low- and middle-income countries to document factors behind global access to and country demand for VVMs. Such results could help identify actions needed to ensure continued use of VVMs in countries that transition out of Gavi support. METHODS: We performed a systematic review of electronic databases, reference lists, and grey literature in English and French languages with publication dates from 2005 onwards. The studies included were analyzed for the following outcomes: (1) availability and deployment of VVM-labeled vaccines; (2) VVM practices and perceptions in the immunization system; (3) vaccine introduction and decision-making processes; (4) Gavi graduation and vaccine program sustainability. RESULTS: The study found that VVM availability and use was affected by multiple sourcing of vaccines and the extent to which VVM was included in the vaccine specification in the tendering documents when procuring vaccines. Knowledge about VVM and its impact on the EPI program was found to be high among health workers as well as decision-makers. However, the study also found that weak capacity in key national institutions such as NRA and NPA might impact on demand for VVM. As countries take decisions regarding the adoption of new vaccines, factors such as disease burden and vaccine price may assume greater importance than vaccine characteristics and presentation. Finally, the study found that countries rely largely on the advice and recommendations from technical partners such as WHO and PAHO. CONCLUSION: The study concludes that global access to and country demand for VVM are dependent on policy statements and recommendations about VVM by key policy institutions such as WHO and UNICEF. The study also concludes that despite Gavi-eligible countries having access to VVM-labeled vaccines, inclusion is often below 100%. Weak institutional capacity in key national agencies such as NRA and NPA seems to be a contributing factor, while other factors include the procurement of clear national policies on the inclusion of VVM on vaccines, along with the capacity to enforce the policy. Finally, the study concludes that knowledge about VVM and its impact on vaccine program efficiency, safety, and cost is critical for transitioning countries' continuous demand for VVM.
Assuntos
Armazenamento de Medicamentos , Programas de Imunização , Refrigeração/instrumentação , Refrigeração/métodos , Vacinas/provisão & distribuição , Países em Desenvolvimento , HumanosRESUMO
Vaccine cold chain equipment (CCE) in developing countries is often exposed to harsh environmental conditions, such as extreme temperatures and humidity, and is subject to many additional challenges, including intermittent power supply, insufficient maintenance capacity, and a scarcity of replacement parts. Together, these challenges lead to high failure rates for refrigerators, potentially damaging vaccines and adversely affecting immunization coverage. Providing a sustainable solution for improving CCE performance requires an understanding of the root causes of failure. Project teams conducted small-scale studies to determine the root causes of CCE failure in selected locations in Uganda and Mozambique. The evaluations covered 59 failed refrigerators and freezers in Uganda and 27 refrigerators in Mozambique. In Uganda, the vast majority of failures were due to a cooling unit fault in one widely used refrigerator model. In Mozambique, 11 of the 27 problems were attributable to solar refrigerators with batteries that were unable to hold a charge, and another eight problems were associated with a need to adjust thermostat settings. The studies showed that tracking and evaluation of equipment performance and failure can yield important, actionable information for a range of stakeholders, including local CCE technicians, the ministry of health, equipment manufacturers, and international partners such as the United Nations Children's Fund, World Health Organization, and Gavi, the Vaccine Alliance. Collaborative efforts to systematically collect and communicate data on CCE performance and causes of failure will help to improve the efficiency and reach of immunization programs in low- and middle-income countries.
Assuntos
Armazenamento de Medicamentos/métodos , Falha de Equipamento , Refrigeração/instrumentação , Vacinas/provisão & distribuição , Humanos , Programas de Imunização , Moçambique , UgandaRESUMO
BACKGROUND: Since 2010, numerous new technologies have entered the immunization cold chain equipment market. The World Health Organization (WHO) Immunization Devices Programme-Performance, Quality and Safety (PQS)-has played a key role in bringing these to market. In this article, the authors explore the emergence of new cold chain equipment technologies from 2004 to 2016 and the role of PQS in this evolution. METHODS: This review focuses on three major vaccine cold chain technology innovations-solar direct-drive refrigerators, long-term passive cold boxes, and equipment with user-independent freeze prevention. For the review, we used online data from WHO PQS, a literature search, and unpublished research reports. RESULTS: Timelines with key milestones in the emergence of the three focus technologies show delays of between one and three years between earliest field trials and publication of WHO specifications; procurement builds after the WHO prequalification of initial devices. DISCUSSION: The timelines show the role of PQS as both gatekeeper and enabler for cold chain equipment technologies. The use of target product profiles by PQS has increased its ability to signal preferred attributes and to engage with manufacturers during the product-development stage. Procurement data show how demand for solar direct-drive refrigerators increased over time. Gavi, the Vaccine Alliance, is employing demand-generation strategies to try to drive procurement of technologies with favorable technical attributes.
Assuntos
Armazenamento de Medicamentos/métodos , Equipamentos e Provisões , Imunização/métodos , Invenções , Refrigeração/instrumentação , Vacinas/provisão & distribuição , HumanosRESUMO
Gavi, the Vaccine Alliance, supports immunisation programmes in eligible countries to reach children with lifesaving vaccines. Dramatic improvement in the scale and performance of current cold chain systems is required to extend the reach of immunisation services - especially for children living in remote locations - to advance progress towards full vaccine coverage. Achieving these improvements will require a healthier market for cold chain equipment where the products meet user needs, are sustainably priced, and are available in sufficient quantities to meet demand. Yet evidence suggests that the cold chain market has suffered from several failures including limited demand visibility, fragmented procurement, and insufficient information exchange between manufacturers and buyers on needs and equipment performance. One of Gavi's strategic goals is to shape markets for vaccines and other immunisation products, including cold chain equipment and in 2015, Gavi created a new mechanism - the Cold Chain Equipment (CCE) Optimisation Platform - to strengthen country cold chain systems by offering financial support and incentives for higher performing CCE. The main objective of the CCE Platform is to get more equipment that is efficient, sustainable, and better performing deployed to every health facility where it is required at an affordable price. To achieve these objectives, Gavi is putting in place tested market shaping approaches and tools adapted for the CCE market: the development of market strategies or 'roadmaps'; improvement of product performance through the development of target product profiles (TPPs); strategic engagement with CCE manufacturers and countries to enhance information sharing; and tailoring procurement tactics to the CCE market. These approaches and tools will allow for increased demand and supply of higher-performing, cost-effective and quality products. By strengthening immunisation systems with improved cold chain equipment, Gavi countries can begin to address the underlying problems limiting vaccine availability and improve the coverage and equity of vaccines.