This thesis aims to provide an overview of microcirculation, including its anatomy and hemorheological properties. Within the framework of microcirculatory dysfunction, there are 4 main types, and their effects are seen in sepsis and ischemia-reperfusion injury. There are various diagnostic methods to evaluate microcirculatory dysfunctions, which help deepen our understanding of microcirculation and its role in various diseases. Therapeutic strategies aimed at improving macrocirculatory parameters may have no effect or even deteriorate microcirculatory parameters; as such, microcirculation should be closely monitored during resuscitation. By addressing these objectives, this thesis underscores the importance of microcirculation and its value in improving diagnostic monitoring and treatment strategies in the management of critically ill patients.