Recent discussions
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Maria Ladjane Leite Soares
Mt bom ! -
ILCOR Staff
From ALS Chair Kate Berg:Response: Dr. Chapman, thank you very much for your comments. First, while we agree that the available data did not allow for statistical comparison of DSED and VC, it is also the case that DSED compared with SD showed statistically significant benefits for all outcomes, while this was not the case for VC compared with SD. This is why the TF came to the conclusions it did, after extensive discussion. We include some of this discussion in the evidence to decision section and have included it as a knowledge gap. We agree about the importance of the sample size being smaller than planned due to the trial stopping early, and that the effect size might be an overestimate, which is why the evidence was downgraded for imprecision. The lack of comparison between DSD and VC, however, was not as a result of stopping the study early. The study was never designed to compare DSD to VC. Second, we agree that none of the currently available defibrillators are designed for DSED. We have discussed the importance of pad placement for SD, possible concerns about defibrillator damage and the reasoning for recommending the approach (single operator activating the shock with one hand, sequentially) used in the trial as well, as we agree that these are important considerations. Third, we are happy to ask ILCOR leadership to extend the public comment period. -
ILCOR Staff
Response from ALS Chair Kate Berg: Thank you Dr. Cheskes for the comments regarding your trial. Risk of bias and certainty of evidence were discussed extensively with the task force, and decisions were not easy to come to. The task force opinion is that there is a potential risk of bias in unblinded studies (unavoidable in this case) because whether the study intervention or a different intervention is used may depend on the clinician’s opinion about the intervention or their opinion about the specific patient. There was a significant amount of crossover between the 3 study treatments, which was not evenly distributed. Exactly why this occurred or how it could have influenced the results is not entirely clear, but the task force felt that this may indicate a potential source of risk of bias. Thank you for clarifying how termination of VF/VT was determined. We can make that adjustment in the relevant GRADE tables. Regarding the assessment of imprecision, we think the optimal information size was appropriate to invoke. GRADE recommends the optimal information size (OIS) as a “second, necessary criterion to consider.” The concept of optimal information size is meant to prompt downgrading for imprecision when you do not think the sample size was adequate to be a true population estimate, based on a conventional sample size calculation. Since the goal is to detect when an effect size reported in a smaller trial may not reflect the true effect size, systematic reviewers are advised to calculate a sample size based on relative risk difference of 20-30%, not on the effect size observed in the trial in question (see GRADE handbook section on imprecision 5.2.4.1, #2 under “dichotomous outcomes,” and then see Example 3). We thought the original sample size calculation conducted by your group was reasonably close to the GRADE recommendation for that calculation so relied on that for the OIS. The fact that survival increased more than your group initially hypothesized is notable and may reflect the true effect, but there is risk of overestimation of treatment effect when trials are stopped early (Liu et al, Trials 23, 747, Sept 2022; Guyatt et al, BMJ ;344:e3863, 2012), so we think determining OIS based on a more conservative sample size calculation is prudent. Overall, the task force opinion is that a single trial of approximately 130 patients per study group almost by definition cannot provide higher certainty evidence for what is a considerable practice change, and we think GRADE methodology supports that determination. -
Janet Bray (BLS Task Force Chair)
Thank you for your interest in this review. -
Kris Arnold
This is an important, evolving topic. In my opinion, it is still at the scoping report level. Hopefully publication of this will serve as a milestone in the development of this trend. It is unfortunate that at least one website promoting the use of drone-delivered AEDs demonstrated a collapsed person, presumably in cardiac arrest, not receiving any CPR while the bystander communicates with the emergency services to arrange and then retrieve the delivered AED from outside a gymnasium-like building. This raises a practical question if there is only one responder who does, correctly, begin compressions needing, then, to also retrieve the drone. I relate this only to make the point that developing effective drone-AED programs will require both flexibility/variability in the drones and careful thought on the part of the agency's deploying a response system. I look forward to your next report on this in another 3-5 years. -
Syed Moied Ahmed
1. Drone AED will definitely reduce the time to defibrillate 2. It will reduce the requirement of manpower 3. However, it will be not get of other benefits or the additional of EMS, specially the presence of expert opinion and extra hands 4. There should be a RCT framed to resolve this question. -
Olivier Wagner
I am teaching BLS and FA since 30 years, I am a Heart and Stroke master-instructor and I love the 4 stepwise approach! Thanks for this study! -
Daniel Serrano
I appreciate the ILCOR task force, -
Fred Chapman
I appreciate the ILCOR task force’s prompt analysis of the DOSE VF Trial. There are a few details that I would like to submit for consideration. First, the primary endpoint of the trial showed that both vector change (VC) and DSD had a benefit over standard care. The trial stopped early, was consequently underpowered and did not compare VC and DSD, so cannot provide accurate relative assessment of the two techniques. That the CoSTR recommends DSD over VC is not consistent with these limitations and is not consistent with the authors’ conclusion in the paper. Due to the limited information available through this trial, it may be premature to draw a conclusion on the superiority or inferiority of VC and DSD Second, it is worth noting that it is likely that none of the defibrillators available today were designed for DSD, and that DSD may be an off-label use of these devices. Defibrillator damage can occur with some DSD techniques, as has been reported in the literature, but was reported not to have occurred in DOSE VF. It is appropriate you have included the statement: “If a double sequential defibrillation strategy is utilized, we suggest an approach similar to that in the available trial, with a single operator activating the defibrillators in sequence. (good practice statement)”. A second aspect of the DSD practiced in the trial is also worth reinforcing: the specific choice of anterior-lateral and anterior-posterior pad placement for the two shock vectors. Other DSD vectors and other shock timing practices may have higher risk of incapacitating the defibrillator. Lastly, I am concerned that the comment period for this complex topic is ending too early for there to have been robust comment from the public. No letters to the editor in response to the report of the single cluster-randomized study published in NEJM have even yet been published. It may be beneficial to extend the comment period and increase visibility to this draft through appropriate channels. I would like to sincerely thank the ILCOR task force for your consideration of these comments. -
Janet Bray
Thank you for your considered feedback. We believe many of your points are covered in the justification and evidence to decision framework. Some points are beyond the scope of this systematic review and are knowledge gaps.