Comparison of acid-base and electrolyte changes following administration of 6% hydroxyethyl starch 130/0.42 in a...

To evaluate the effects of a 6% hydroxyethyl starch (130/0.42) in either a buffered, electrolyte-balanced (HES-BAL) or saline (HES-SAL) carrier solution on electrolyte concentrations and acid-base parameters in healthy anaesthetized dogs.

Prospective randomised clinical study.

A group of 40 client-owned dogs undergoing general anaesthesia for elective surgical procedures or diagnostic imaging.

During anaesthesia, dogs were intravenously administered 15 mL kg^-1 of either HES-SAL (n = 20) or HES-BAL (n = 20) over 30-40 minutes. Jugular blood samples were analysed before (T₀) and 5 minutes (T₅), 1 hour (T₆₀) and 3 hours (T₁₈₀) after fluid administration. Sodium, potassium, chloride, ionised calcium, phosphate, albumin, pH, venous pCO₂, base excess (BE), bicarbonate and anion gap were determined and strong ion difference (SID) and total quantity of weak nonvolatile acids were calculated for each time point.

Chloride was significantly increased at T₅, T₆₀ and T₁₈₀ compared with T₀ after HES-SAL, and was significantly greater after HES-SAL than after HES-BAL at T₅ (p = 0.042). Ionised calcium was significantly decreased at T₅ compared with T₀ after HES-SAL, and was significantly lower after HES-SAL than after HES-BAL at T₅ (p < 0.001). Bicarbonate was significantly lower after HES-SAL than after HES-BAL at T₅ (p = 0.004) and T₆₀ (p = 0.032). BE was significantly lower after HES-SAL than after HES-BAL at T₅ (p < 0.001) and T₆₀ (p = 0.007). SID was significantly decreased after HES-SAL at T₅ and T₆₀ compared with T₀, and was significantly lower after HES-SAL than after HES-BAL at T₅ (p = 0.027). Mean electrolyte and acid-base parameters remained within or marginally outside of reference intervals.

Changes in both groups were minor and short-lived with either fluid in healthy individuals, but might become clinically relevant with higher fluid doses or in critically ill dogs.