Kipas elektrik untuk mengurangkan impak buruk terhadap kesihatan akibat gelombang haba
Abstract
Background
Heatwaves are hot weather events, which breach regional or national thresholds, that last for several days. They are likely to occur with increasing frequency in some parts of the world. The potential consequences were illustrated in Europe in August 2003 when there were an estimated 30,000 excess deaths due to a heatwave. Electric fans might be used with the intention of reducing the adverse health effects of a heatwave. Fans do not cool the ambient air but can be used to draw in cooler air from outside when placed at an open window. The aim of the fans would be to increase heat loss by increasing the efficiency of all normal methods of heat loss, but particularly by evaporation and convection methods. However, it should be noted that increased sweating can lead to dehydration and electrolyte imbalances if these fluids and electrolytes are not replaced quickly enough. Research has also identified important gaps in knowledge about the use of fans, which might lead to their inappropriate use.
Objectives
To determine whether the use of electric fans contributes to, or impedes, heat loss at high ambient temperatures during a heatwave, and to contribute to the evidence base for the public health impacts of heatwaves.
Search methods
We sought unpublished and published studies that had been published in any language. The review team were able to assess studies reported in English, Chinese, Dutch, French and German; and reports in other languages would have been translated into English as necessary. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, the Indian biomedical literature (IndMED and MedIND) and databases of Chinese literature (Chinese Journal Net and Digital Periodical of WanFang Data). The most recent electronic searches were done in April 2012. We also checked the reference lists of relevant articles and the websites of relevant national and international organisations, and consulted with researchers and policy makers with experience in strategies to manage heatwaves to identify additional studies. The titles and abstracts from each search were checked independently by two review authors. The full text articles that we retrieved were checked independently by at least two authors for their relevance and for references to potentially eligible studies.
Selection criteria
Randomised trials and other experimental designs, such as interrupted time series and controlled before‐and‐after studies, comparing the use of electric fans with no fans during a heatwave were eligible for this review. The electric fans could be hand‐held (battery operated), portable or mounted on the wall or ceiling, or in a window. We sought interventions delivered to anyone for whom a heatwave was likely to have serious adverse health impacts. This would include people of all ages but with a particular focus on some groups (for example older people). Populations from high‐, middle‐ and low‐income countries were eligible for the review.
Data collection and analysis
If we had identified eligible studies, they would have been assessed independently by at least two review authors and data would have been extracted on the characteristics of the study, its participants and interventions, as well as the effects on health outcomes. The primary outcomes were mortality, hospital admission and other contacts with healthcare services.
Main results
We did not identify any eligible studies despite the extensive searching and correspondence with several experts in this topic area. We identified retrospective, observational studies, usually with a case‐control design, that investigated the association between the use of electric fans and health outcomes, including death. The results of these studies were mixed. Some studies found that the use of fans was associated with better health outcomes, others found the reverse.
Authors' conclusions
The evidence we identified does not resolve uncertainties about the health effects of electric fans during heatwaves. Therefore, this review does not support or refute the use of electric fans during a heatwave. People making decisions about electric fans should consider the current state of the evidence base, and they might also wish to make themselves aware of local policy or guidelines when making a choice about whether or not to use or supply electric fans. The main implication of this review is that high quality research is needed to resolve the long standing and ongoing uncertainty about the benefits and harms of using electric fans during a heatwave, for example randomised trials comparing the health effects in people with electric fans to those in people without them.
PICO
Plain language summary
Kipas elektrik untuk mengurangkan kesan kesihatan akibat gelombang haba
Gelombang haba dijangka menjadi lebih kerap terjadi dan kesannya boleh memudaratkan. Sebagai contoh, sehingga 30,000 orang mungkin telah maut akibat gelombang haba yang berlaku di Eropah pada Ogos 2003. Satu cara untuk mendapat kelegaan daripada haba adalah dengan menggunakan kipas elektrik, tetapi sama ada ini akan mendatangkan lebih banyak kebaikan atau kemudaratan tidak dapat dipastikan. Kipas mungkin membantu untuk meningkatkan kehilangan haba jika suhu adalah di bawah 35 °C dan kipas tidak ditujukan terus terhadap individu itu, tetapi apabila suhu melebihi 35 °C, kipas mungkin sebenarnya menyumbang kepada penambahan haba. Berpeluh secara berlebihan juga boleh menyebabkan dehidrasi dan masalah kesihatan yang lain. Oleh itu, adalah penting untuk mengetahui tentang manfaat dan mudarat kipas elektrik yang mungkin ada apabila memilih sama ada untuk menggunakannya. Ulasan ini terpakai sekiranya keputusan menggunakan kipas tersebut melibatkan anda sendiri, tetapi ia juga relevan untuk keputusan pihak berkuasa kesihatan awam yang lebih meluas, seperti sama ada untuk memberikan kipas elektrik kepada sekumpulan individu semasa gelombang haba. Perkara ini penting bagi mereka yang dikira lebih terdedah kepada kesan haba, seperti orang tua yang kurang berupaya menyejukkan badan secara berpeluh atau meningkatkan aliran darah ke kulit mereka.
Ulasan Cochrane ini cuba untuk memberikan beberapa jawapan yang dapat membantu pembuat keputusan. Kami mencari penyelidikan berkualiti tinggi yang membandingkan sekumpulan individu yang menggunakan kipas dengan sekumpulan lain yang tidak menggunakannya semasa gelombang haba. Walau bagaimanapun, kami tidak menemui sebarang penyelidikan yang memenuhi ciri‐ciri kami. Kami menemui beberapa kajian yang menggunakan rekaan yang kurang kukuh untuk menjawab soalan sebegini, dan ini memberikan keputusan yang bercampur‐campur. Ada yang mencadangkan bahawa kipas mungkin mengurangkan masalah kesihatan, sementara yang lain mencadangkan bahawa kipas mungkin memburukkan keadaan.
Oleh itu, kajian yang telah dijalankan setakat ini tidak menyelesaikan ketidakpastian tentang kesan kesihatan penggunaan kipas elektrik semasa gelombang haba. Mereka yang perlu membuat keputusan patut mempertimbangkan bukti terkini, di samping polisi dan garis panduan tempatan apabila membuat pilihan mereka. Mereka mungkin ingin membantu menyelesaikan ketidakpastian yang berterusan ini dengan menjalankan jenis kajian berkualiti tinggi yang dapat mendatangkan bukti kukuh yang diperlukan untuk menentukan manfaat dan mudarat penggunaan kipas elektrik semasa gelombang haba.
