Crystalloids versus colloids for resuscitation is an age old debate! In this episode I present the following paper before going on to talk about the use of colloids in hypoproteinaemia. Click Here For Your FREE Copy of a Transcript of This Episode For online presentations and notes on Hypovolaemia and Shock and Parenteral Fluid Therapy visit my online training portal. Cazzolli D, Prittie J. The crystalloid-colloid debate: Consequences of resuscitation fluid selection in veterinary critical care. J Vet Emerg Crit Care 2015. Early View online 22 January. ABSTRACT Objective: To provide a comprehensive review of the current literature in human and veterinary medicine evaluating the impact of resuscitation fluid choice on patient outcome and adverse effects. Data Sources: Prospective and retrospective studies, experimental models, and review articles in both human and veterinary medicine retrieved via PubMed. Human Data Synthesis: A series of recent, large, randomized controlled trials in critically ill human patients comparing crystalloid versus colloid driven fluid resuscitation algorithms have demonstrated no outcome benefit with the use of natural or synthetic colloids. Synthetic colloidal solutions are associated with an increased incidence of adverse effects including acute kidney injury, need for renal replacement therapy, and coagulopathies. Further, colloidal solutions demonstrate a larger volume of distribution in the setting of critical illness than hypothesized. These findings have created controversy regarding colloid fluid resuscitation in critically ill patients and challenge current resuscitation strategies. A thorough review of the most influential human data is provided. Veterinary Data Synthesis: No veterinary clinical outcome data pertaining to fluid resuscitation choice currently exist. Veterinary data from experimental and small clinical trials evaluating the coagulopathic effects of hydroxyethyl starch solutions are described. Data pertaining to the use of natural colloids and albumin products in clinical veterinary patients are reviewed. In addition, data pertaining to the comparative intravascular volume expansion effectiveness of different fluid types in canine patients are reviewed. Conclusions: Clinical data from critically ill human patients have failed to demonstrate an outcome advantage associated with colloidal fluid resuscitation and indicate that hydroxyethyl starch solutions may be associated with significant adverse effects, including acute kidney injury, need for renal replacement therapy, coagulopathies, and pathologic tissue uptake. The ability to apply these findings to veterinary patients is unknown; however, similar pathophysiology may apply, and critical re-evaluation of resuscitation strategies is justified.