Recent discussions
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ALS Task Force
Thank you for your comments. Firstly, the ALS Task Force (TF) debated the terms 'comatose' or 'unresponsive', or 'patients who do not awaken soon after ROSC' in the treatment recommendation, and chose 'comatose'. National Councils such as the AHA will be able to provide more detail in their clinical practice guidelines. Our systematic review did not identify any subpopulation for which hypothermia at 32-34oC improves any important or critical outcomes. There was also a view from some TF members not to include the sub population statement at all. The CoSTR statement represents the consensus of the ALS Task Force and states that there is uncertainty about this issue. We have not gone any further than this and made a treatment recommendation on this issue – a similar statement was included in the 2015 treatment recommendation. The TF was concerned that actively rewarming patients who present with mild hypothermia after ROSC may be harmful, and this led to this good practice statement. We accept that alternative rewarming approaches may be possible and this is an area that requires further study. We agree that the issue of shivering requires further study and the ALS TF will consider addressing this in the future. -
ALS Task Force
Thank you for this response. Recommendations 1. We agree that temperature control in cardiac arrest survivors should not be abandoned all together. This will require all National Councils to spread this message to clinicians involved in the care of post cardiac arrest survivors. Whether there has been harm from a decrease in the use of hypothermia after ROSC is uncertain. Two observational studies have looked at this [ 1. Salter, R., et al., Changes in Temperature Management of Cardiac Arrest Patients Following Publication of the Target Temperature Management Trial. Crit Care Med, 2018. 46(11): p. 1722-1730. 2. Nolan, J.P., et al., Changes in temperature management and outcome after out-of-hospital cardiac arrest in United Kingdom intensive care units following publication of the targeted temperature management trial. Resuscitation, 2021. 162: p. 304-311.] The first study from Australia and New Zealand found no significant difference in the slope or “stepwise change” after the publication of the TTM1 trial. This is the most appropriate analysis for a before/after study. In the more naïve analysis, there were also no significant association when adjusting for appropriate variables (i.e., not including temperature variables). In the second study from the United Kingdom, they found similar results when the appropriate model (i.e., accounting for time trends but not including temperature variables) was used. The treatment recommendation suggests the active prevention of fever as opposed to targeting mild hypothermia for at least 72 hours. Justifications 1. We agree that there is wide global variation in cardiac arrest outcomes. In addition there are differences in clinical practices between settings. The TTM studies were done in a range of settings predominantly in Europe where there is also a wide range of outcomes and practices. Our treatment recommendations will need to be adapted by National Councils for local circumstances. 2. and 3. We are aware of these observation studies (Callaway 2020, e208215; Nishikimi 2021, e741) and considered these when making our treatment recommendations. Our systematic review that included RCTs did not find any benefit for hypothermia treatment in any subgroup. 4. We have reviewed numerous studies of time to achieve hypothermia and the time taken in the TTM2 trial was in keeping with these. Time from ROSC to a temperature < 34°C was approximately 5 hours in the TTM2 trial with a time from ROSC to randomization of approximately 2 hours and time from randomization to < 34°C of approximately 3 hours. Data from multiple other randomized trials (including the unpublished CAPITAL-CHILL trial), and from observational studies, have found similar or longer times. The one trial that had a shorter time is the 2002 Bernard trial. The overwhelming evidence, from both randomized trials and “real-life” observational data therefore suggests that a time to target of approximately 5 hours is consistent with clinical practice elsewhere. – this is addressed in more detail with refences in our further responses and the COSTR Evidence to Decision Tables. -
ALS Task Force
Thank you for this response. We have considered all the current available RCT evidence in order to make our treatment recommendations and not just the recently published TTM2 trial, although this study did stimulate our update of the previous CoSTR. We did not identify any sub-populations supporting the use of mild hypothermia in our systematic review and hence our broad recommendation. -
ALS Task Force
Thank you for raising this issue – the ILCOR ALS Task Force has provided a consensus on the science and treatment recommendation for National Councils (e.g., AHA) to adapt for treatment guidelines for clinical practice. As stated in the responses to others, our systematic review did not identify any subpopulations where mild hypothermia was beneficial. National Councils will provide more detailed guidance for clinical practice based on local and regional values and preferences. -
ALS Task Force
Thanks you for your comment. We have carried out a systematic review [Granfeldt A, Holmberg MJ, Nolan JP, Soar J, Andersen LW; International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force. Targeted temperature management in adult cardiac arrest: Systematic review and meta-analysis. Resuscitation. 2021;167:160-172.] that included the RCTs. The Task Force members are also aware of and considered the animal and observational data in making these treatment recommendations. -
ALS Task Force
Thanks you for your comment. We have carried out a systematic review [Granfeldt A, Holmberg MJ, Nolan JP, Soar J, Andersen LW; International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support Task Force. Targeted temperature management in adult cardiac arrest: Systematic review and meta-analysis. Resuscitation. 2021;167:160-172.] that included these earlier RCTs. We agree that many aspects of post resuscitation care have changed since these previous RCTs. We would go further and describe these as improvements in care – our meta-analysis used a random effects model that actually gave the older studies a greater weighting than many task force members considered justified given the changes in practice since when these studies took place. We agree changes in prognostication and delaying withdrawal of life support could be an important factor. We address the issues of propofol and speed of cooling in our response to Nichol. -
ALS Task Force
Thank you for your feedback. The ALS TF has followed the GRADE convention and used the term 'suggest' in treatment recommendations that are weak recommendations based on low or very -low certainty evidence. -
ALS Task Force
Thank you for your feedback. The ALS task Force considered the two publications and considered giving a stronger statement for the use of hypothermia at 32-34oC in some subpopulations – however our systematic review of the available evidence did not identify any subpopulation for which hypothermia at 32-34oC improves any important or critical outcomes. There was also a view from some TF members not to include this statement about subpopulations at all. The CoSTR statement represents the consensus of the ALS Task Force and states that there is uncertainty about this issue. -
ALS Task Force
Thank you for raising this issue – the ILCOR ALS Task Force has provided a treatment recommendation for national councils (e.g., AHA) to adapt for treatment guidelines for clinical practice. Our treatment recommendation is advocating fever prevention and we have provided the upper limit of temperature to achieve fever prevention and as done in the TTM study - the commentary with the CoSTR addresses this issue. -
ALS Task Force
Thank you for your feedback. This was a difficult topic on which to achieve TF consensus on treatment recommendations. The rationale for the recommendations is provided in the justifications section. As stated in response to others, our systematic review did not identify any subpopulation for which hypothermia at 32-34oC improves any important or critical outcomes. There was also a view from some TF members not to include this statement at all. The CoSTR statement represents the consensus of the ALS Task Force and states that there is uncertainty about this issue.