To the Editor.
—We read with interest the recent report by Sack et al1 that described the technique of IAC during CPR for in-hospital cardiac arrest. In light of the recent media attention to this report we feel certain cautionary notes should be underlined.First, as expressed by the authors, this study was not blinded to the investigators or participants and therefore runs a very real risk of observation and expectation bias. Although the duration of CPR expressed as the median time in minutes between groups did not significantly differ, there was no standardization for chest compression force and no information was provided about DC countershock in the two groups. Perhaps measurements of end-tidal carbon dioxide tension would provide further information as to the relative efficacy of each technique and would improve standardization.2Second, the number of patients who achieved meaningful survival (neurologic class I and II)3
Nathan PE, Sacchi TJ. Countering Cardiac Counterpulsation. JAMA. 1992;267(19):2601-2602. doi:10.1001/jama.1992.03480190043015