Fluid Therapy in Anesthetized Animals During Uncontrolled Hemorrhage: What is the Evidence?
Robert Hahn may have stated it best when he said, “Fluid therapy may be more difficult than you think” (2007). This manuscript title can be interpreted in many ways but highlights the fact that fluids are drugs and their administration is context (i.e. circumstance) sensitive (i.e. individual animal dependent). Seven key questions should be answered every time fluid therapy is considered: who, what, why, when, where, how, how much, and expected outcome (W5H2O1). If monitoring is included then the acronym is extended to WHOM. Importantly the answers to these questions change with context and become vitally important following controlled and uncontrolled hemorrhage during anesthesia. Fluid therapy for these situations requires deliberation of oxygen delivery to tissues (DO2), the duration and repayment of oxygen debt (O2D), acid-base and electrolyte abnormalities and the ability to establish “hemodynamic coherence”. It also necessitates consideration of the animals hemoglobin concentration, osmolarity and the extent and type (ex. soft tissue; orthopedic; respiratory; CNS) of tissue damage (i.e. inflammation) produced. This seminar will discuss the physiology and pathophysiologic processes that guide the answers for WHOM in anesthetized animals during controlled and uncontrolled hemorrhage.