Prompt admission to the ICU: an instrument to improve mortality for deteriorating ward patients

In a recent article in Intensive Care Medicine, Harris and co-authors present a study on the importance of prompt transfer of deteriorating ward patients to the ICU [1]. Between 2010 and 2011, they conducted a large observational study involving 49 hospitals in the UK considering the problem of ongoing bed block causing unwanted delays in the admission of patients. We would like to congratulate the authors on conducting such challenging and groundbreaking study designed to answer a valid but also somewhat delicate research question. A key feature of this study is the applied instrumental variable (IV) analysis, which we believe has a non-harvested potential within critical care research.