tools to HR and RR time series during weaning trials and compared these analyses between successfully weaned patients and those who failed weaning. They found that patients who had successful weaning had a more complex pattern of HR and RR patterns than those who failed. They proposed a model to predict weaning that was more accurate for their group of patients than the conventional model that included rapid shallow breathing index and airway occlusion pressure at 0.1 second. Although the results are very interesting, they cannot be endorsed for 2 main reasons. First, they are very complex to perform and are not fully understood by physicians. In addition, the current results can only serve as a hypothesis for future studies. Despite these reservations, it is important to realize that the future of complex signal analysis is drawing near and that we, the clinical community, have to start to embrace this complex mathematical field if we wish to understand the information we derive from our physiologic monitoring devices.