Anatomy and Physiology of Intraosseous Infusion

The introduction of fluids and medications via intraosseous (IO) infusion is highly dependent upon many unique aspects of bone anatomy and physiology. Key considerations include differences in the medullary cross-sectional area between insertion sites, age- and location-dependent variation in the distribution of red and yellow bone marrow, volume and pressure capacity within the venous system, and influence of hormones and other chemical messengers on vasomotor tone. In addition to an exploration of these concepts, this chapter also discusses the physiologic basis for pharmacokinetic relationships reported in the prevailing literature and proposes methods to optimize the use of IO infusion in the care of critically ill patients.