Fluids, pH, ions and electrolytes.

PURPOSE OF REVIEW: Significant attention has been recently focused on both maintenance fluid and resuscitation fluid use in critical care. Accordingly, a focused review of the properties of crystalloid and colloid fluids, their expected benefits, and potential deleterious side effects is appropriate and timely.

RECENT FINDINGS: Despite their ubiquitous use, well described side effects, and ability to be titrated to a physiologic endpoint, fluids are rarely considered in a fashion similar to other pharmacologic agents. Understanding their physical and chemical properties allows the clinician to understand, anticipate and deliberately harness their expected impact on acid-base balance. Expanded insights into the pathogenesis of common acid-base disorders may be gleaned from utilizing a physicochemical approach that allows the precise quantification of the ionic species that impact pH.

SUMMARY: This focused review further enables the clinician to appropriately investigate, modify, and optimize bedside clinical care related to fluid and acid-base management.