The aim of this book is to spread and make easier the use of comprehensive modelling for research, educational and clinical applications. Flexible and modular numerical, physical and hybrid models developed to assess patho-physiology of cardiovascular and respiratory systems are the subject of the book. The models discussed in the book are effective and easy to use tools to simulate circulatory and respiratory systems, their interactions and their mechanical support. The models can be applied to analyse data, predict the trend of selected variables not routinely measured and to identify critical variables to be monitored. Spreading of comprehensive modelling can offer to physicians and engineers powerful tools to analyse complex phenomena and interactions involving circulatory and respiratory systems along with their mechanical assistance. The complexity of the circulatory and respiratory systems makes their analysis very difficult or sometimes impossible in clinical environment.