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Abstract
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We thank Chao Zhou et al. for raising potential issues of our original article and giving us the chance to discuss those.
First as Zhou et al. point out - as also discussed by us in the original article - that the missing confirmation of poisoning as cause of the cardiac arrest is a major limitation of our study. Using lab testing or other methods to proof poisoning would be preferable, but is difficult in practice. Estimating the true number of P-OHCA on the basis of our study, large numbers of patients would need to undergo laboratory testing and autopsy - making such a study extremely complex and costly. Additionally, in the EMS prehospital setting, where most of our data is generated from, neither results of autopsy or laboratory testing, obtained later in the hospital, are available. Therefore, a practically relevant and valid insight of our study is, that if the prehospital emergency physician attributes OHCA to poisoning, even without including patients with a definite proof of poisoning only, the outcome is better.
Second, Zhou et al. claim that multivariate analysis might be biased because of too high number of analysed cases. The contrary is the case. A high case number leads to a higher statistical certainty and may even detect weaker prognostic factors. In our study, poisoning was shown to be a strong independent protective predictive factor.
Third, we kindly disagree with Zhou et al. that there is no rationale why patients with P-OHCA could have a better outcome. As previously discussed in the original study other data, exemplary from the USA, also suggest a better outcome in overdose-associated cardiac arrest in comparison to other causes of arrest.
We especially disagree with the studies cited by Zhou et al. being supportive for their reasoning...
Language: en |