In Intensive Care Medicine (ICM) the presence of multiple high tech devices is common in order to perform multiple medical and non-medical procedures. The authors intend to perform a critical appraisal on the basic and practical/clinical approach to monitoring devices, analyzing the evidence support regarding clinical effects, end-points, and patient safety. All data that provides a diagnosis or a characterization of the patient's status will be considered diagnostic information whereas, variables that could be achieved by medical interventions will be considered therapeutic end-points. In any healthcare setting a careful approach to the patient is needed, namely in ICM one must consider the patient's clinical condition and choose adequate diagnostic tools and devices. Not all variables and devices currently on the market are suitable for each patient, nor proved useful in the setting under study. Also, all patients are different and must be approached differently according to established clinical end-points, translating into more holistic caregiving. ICM requires a personalized approach towards the patient, consequently, submitting diagnostic tools and monitoring devices to greater scrutiny in order to obtain greater patient benefit.