Regarding Lactic Acid: 1 Why did the authors report median and IQR rather than mean and SD? angiography vs. 32% with delayed angiography) 2. Note that the authors refer to the meta-analysis odds ratio (2.78) and 95% confidence interval (1.89 to 4.10). What is the relevant relative risk (risk ratio, RR) for overall survival here? 3. In their last sentence above, the authors state that they are looking for a 40% difference. Is this a relative or an absolute difference? Explain how this 40% difference relates to their survival to 90 days expectation (percentages in parentheses). State the appropriate risk ratio.

Fig: 1