0.9% saline is neither normal nor physiological

Electrolyte Disturbances Are Associated with Non-Survival in Dogs-A Multivariable Analysis

Electrolyte disorders have been individually associated with mortality in small populations of dogs and cats with specific conditions, but the associations and interactions between electrolyte disturbances and outcome have not been evaluated in a large, heterogeneous population. It was hypothesized that abnormalities of sodium, chloride, potassium, and calcium concentrations would be independently and proportionately associated with death from natural causes and with all-cause mortality in dogs. An electronic database containing 33,117 electrolyte profiles was constructed to retrospectively assess the association between disorders of sodium, potassium, corrected chloride, and ionized calcium concentrations with non-survival and with death excluding euthanasia by multivariable modeling. A second database containing 11,249 records was used to validate the models constructed from the first database. All four electrolytes assessed had non-linear U-shaped associations with case fatality rates, wherein concentrations clustered around the reference interval had the lowest case fatality rates, while progressively abnormal concentrations were associated with proportionately increased risk of non-survival (AUROC 0.624) or death (AUROC 0.678). Multivariable modeling suggested that these electrolyte disturbances were associated with non-survival and with death from natural causes independent of each other. This study suggests that measurement of electrolyte concentrations is an important component of the assessment of dogs in emergency rooms or intensive care units. Future studies should focus on confirming these associations in a prospective manner accounting for disease severity.

Intravenous Fluids and Acute Kidney Injury

Over 50% of the human body is comprised of fluids that are distributed in defined compartments. Although compartmentalized, these fluids are dynamically connected. Fluids, electrolytes, and acid-base balance in each compartment are tightly regulated, mostly in an energy-dependent manner to achieve their designed functions. For over a century, our understanding of the microvascular fluid homeostasis has evolved from hypothesized Ernest Starling principle to evidence-based and the revised Starling principle, incorporating the functional endothelial surface layer. The kidney is a highly vascular and encapsulated organ that is exquisitely sensitive to inadequate (insufficient or excess) blood flow. The kidney is particularly sensitive to venous congestion, and studies show that reduced venous return triggers a greater degree of kidney damage than that from lacking arterial flow. Thus, fluid overload can induce severe and sustained kidney injury. In the setting of established acute kidney injury, fluid management can be challenging. Impaired capacity of urine output and urine concentration and dilution should be taken into consideration when designing fluid therapy. Video Journal Club 'Cappuccino with Claudio Ronco' at http://www.karger.com/?doi=452702.