Intravenous fluid administration and controversies in Acid-base.
OBJECTIVE
To present an overview of acidosis following intravenous fluid infusion and to highlight the current controversy in acid-base physiology.


METHODS
Articles and reviews from peer reviewed journals and books on acid-base physiology and post infusion acidosis.


RESULTS
Infusion of intravenous fluids can produce an acidosis particularly in the setting of large volume infusion. The explanation of this phenomenon has centred around dilution of plasma bicarbonate. An alternative explanation can be found in the work of Peter Stewart, which highlights the use of strong ion difference in assessing metabolic acidosis. The Stewart approach differs from the traditional Henderson-Hasselbalch approach to acid-base. Further study is required to determine which approach is correct. Solutions containing base anions such as lactate may attenuate such an infusion acidosis. Animal and clinical studies using Hartmann's solution and Plasmalyte 148 support this idea.


CONCLUSIONS
There is controversy regarding mechanisms in acid-base physiology. The clinical significance of post infusion acidosis is unclear, however use of Hartmann's solution may minimize the acidosis.
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Department of Anaesthesia, Austin and Repatriation Medical Centre, VIC Australia.