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deficit between these two methods. Statistically there were significantly more patients out of temperature range while maintaining therapy in the surface cooling group, and an increase in median time spent outside targeted temperature as well. This work further supported earlier studies 22 that advocated the use of either surface pads or intravascular devices for the induction of hypothermia but strongly recommended intravascular devices for maintaining target temperature. The National Institute for Health and Care Excellence updated its advice on TTM in July 2017 to advocate the use of Arctic Sun over conventional or intravascular cooling methods, due to a combination of reduced risks associated and the potential for improved outcomes. Conclusions TTM is an extensively researched, effective, neuroprotective strategy with well established guidelines; however, confusion exists about the optimal duration and target temperature. At the time of writing, the most up-to date research would advocate starting TTM as soon as feasibly possible, but not setting low temperatures (that is, 33°C) and simply avoiding temperatures above 36°C. 17 This obviously remains at the clinician’s discretion and temperatures between 35 and 36°C are commonplace. While new devices and research into this treatment are evolving and being undertaken, it is important to reflect on the fundamentals. First, patient selection remains an often-overlooked area, and the authors urge vigilance in selecting those patients who are suitable for instigation of TTM and screening carefully for those likely to benefit from this therapy. To this point, if there is doubt regarding the initial rhythm of arrest, then TTM should be instigated and not withheld. The clinician involved in the decision to commence TTM must pay attention to the precise control of temperature in all phases, and critically in the rewarming phase where a passive, non-controlled rise could have serious effects on outcome. Finally, as with most evolving medical research, there is more work to be done, particularly now that 36°C temperatures are associated with equal outcomes to 33°C. Are we ready to accept normothermia and adopt cooling measures when we see a trend to hyperthermia? References 1 London Ambulance Service Cardiac Arrest Annual Report 2012/2013. www. londonambulance.nhs.uk. 2 Berdowski J et al. Global incidences of out-of-hospital cardiac arrest and survival rates: Systematic review of 67 prospective studies. Resuscitation 2010;81(11): 1479–87. 3 Perkins GD, Brace-McDonnell SJ. The UK Out of Hospital Cardiac Arrest Outcome (OHCAO) project. BMJ Open 2015;5(10):e008736. 4 Bernard SA et al. 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