Methods to safely implement hypothermia in the intensive care unit: a how-to guide

É bem conhecido que o controle da temperatura alvo (CTA) reduz o dano celular secundário após parada cardíaca em pacientes com hipóxia cerebral presumida. O tratamento dessa síndrome de reperfusão, especialmente em termos de controle da temperatura, ainda não é bem compreendido. Diversos estudos clínicos randomizados e controlados, assim como outros estudos, demonstraram a efetividade do CTA na melhora dos desfechos neurológicos.(1) Assim, o CTA é, desde outubro de 2015, recomendado na atualização das diretrizes do European Resuscitation Council.(2) Em resumo, o CTA é indicado para quase todos os sobreviventes após parada cardíaca, sendo que esta afirmativa se apoia em diferentes níveis de evidência. O ritmo inicial (chocável ou não chocável) e o local onde ocorreu a parada (no hospital ou fora dele) não excluem o tratamento se o paciente permanecer comatoso, após retorno da circulação espontânea. Devido aos novos dados publicados, a temperatura alvo recomendada se encontra entre 32oC e 36oC por 24 horas; ainda se desconhece o nível ideal de temperatura alvo assim como sua melhor duração.(3) Além disso, o CTA moderno é apenas parte do cuidado na fase que se segue à parada cardíaca, que inclui intervenção coronária percutânea, controle apropriado dos níveis glicêmicos e regulagem do equipamento de ventilação, para obter normoxia e normocapnia. Diversos levantamentos realizados na Europa revelaram uma crescente aceitação do CTA após parada cardíaca, porém o uso de um controle profissional da temperatura com sistema computadorizado e de um protocolo operacional padrão (POP) ainda se encontra em nível intermediário.(4-6) As razões por trás da relutância são numerosas, mas quando se comparam os benefícios do uso do CTA, no que se refere aos desfechos neurológicos e à recuperação, no futuro algumas destas razões não mais serão aceitáveis.

intensive care unit (ICU). It is important to convince your team of the new method, explain current data and guidelines, and define stakeholders (nurse/physician) and responsible team members for providing training and answering questions of new staff. It is also important to choose the most appropriate cooling device (computer feedback) for your ICU and offer repetitive training on the device. Your stakeholder is very important as he or she is part of your team already, and the team will easily accept training and advice from their own members that are on the same level.

Standard operating protocol
Providing a written SOP is important and should include the criteria for patients who are receiving TTM and exclusion criteria for exceptions; it should also include the indicated target temperature and duration of TTM. A major part of the SOP should be a list of side effects and problems that can occur during treatment and how to avoid, detect and or treat them successfully. During the implementation phase, the SOP and trouble-shooting list should be discussed with your team and adjusted in accordance with their wishes. Typical side effects and their appropriate treatments should be mentioned, such as bradycardia, hypokalemia or shivering. For example, the SOP should advise that counter-warming (gloves and socks) and deep sedation will effectively prevent shivering in most patients if started prior to the occurrence of shivering. If shivering has already been observed, a list of detailed steps for treatment solutions, such as deepening sedation, intravenous magnesium application, and counterwarming, should be provided; if shivering is persistent, muscle paralysis is an important point to mention. Modify your SOP with your team's input, and the SOP will not only enhance the quality of care but also give your team a safer attitude towards implementation of TTM. Engaging your staff at these important steps of implementation will significantly increase the level of acceptance and usage. Additionally, if your team does well, you should tell them. Feedback is another very important key for success and motivation.

The first patients
If possible, invite discharged survivors after cardiac arrest to visit your team as a form of positive feedback. Your first results will also convince the still skeptic team members. It is important that all staff members adopt the new method to guarantee that all patients will receive the best medical care according to the local SOP after a cardiac arrest.

Neurological prognostication
Prognostication has changed remarkably over the last decade. As recommended by current guidelines, a multimodal process of prognostication, including biomarkers such as neuron specific enolase, clinical examination, somatosensory evoked potentials, electroencephalography and computer tomography are useful and important. (7) In addition to this approach, it is clearly recommended not to start prognostication too early to exclude confounders, such as residual sedation. Prognostication should take place between days 3-7. In the case of different or conflicting results, ongoing observation of the patient and re-evaluation is recommended. However, your local SOP should also highlight the important pathways for prognostication and which steps are used for your patients under which conditions ( Figure 1). For successful implementation of a prognostication pathway, a close collaboration with a Neurology department is recommended, if possible.

CONCLUSION
There is no doubt regarding the need for TTM after cardiac arrest to improve neurological outcomes. It is important to define key members of the team and provide a written SOP that includes trouble-shooting, including your team in all the steps of implementation and modifying the SOP according to the team's input. Remember to give feedback after your first patients to motivate your team. Successful implementation of TTM requires teamwork and to "KISS".