A balanced view of balanced solutions

This review of fluid therapy studies using 'balanced' solutions vs isotonic saline fluids (both crystalloids and colloids) aims to address recent controversy in this topic.The change to the acid-base equilibrium based on fluid selection is described. Key terms such as 'dilutional-hyperchloraemic acidosis' (correctly used instead of dilutional acidosis or hyperchloraemic metabolic acidosis to account for both the Henderson-Hasselbalch and Stewart equations), 'isotonic saline' and 'balanced solutions' are defined.The review concludes that dilutional-hyperchloraemic acidosis is a side effect, mainly observed after the administration of large volumes of isotonic saline as a crystalloid. Its effect is moderate and relatively transient, and is minimised by limiting crystalloid administration through the use of colloids (in any carrier). Convincing evidence for clinically relevant adverse effects of dilutional-hyperchloraemic acidosis on renal function, coagulation, blood loss, the need for transfusion, gastro-intestinal function or mortality cannot be found.In view of the very long use of isotonic saline either as crystalloid or as carrier of colloid, the paucity of data documenting detrimental effect of dilutional-hyperchloraemic acidosis and the limited published information on the effects of balanced solutions on outcome, we cannot currently recommend changing to the use of a balanced colloid preparation.