Effects of hetastarch 130/0.4 on plasma osmolality, colloid osmotic pressure and total protein in horses anaesthetised for elective surgical procedures.
Authors: Roska Shannon, Morello Samantha, Rajamanickam Victoria, Smith Lesley J
Journal: The Veterinary record
Summary
# Editorial Summary During equine general anaesthesia, fluid management significantly affects cardiovascular stability and tissue perfusion, making the choice between crystalloid and colloid solutions clinically important. Shannon and colleagues compared hetastarch 130/0.4 (a synthetic colloid) with lactated Ringer's solution (a crystalloid) in 18 healthy horses receiving 4–6 ml/kg intravenously over the first hour of inhalational anaesthesia, measuring plasma osmolality, colloid osmotic pressure (COP) and total protein at baseline and multiple timepoints through to 120 minutes. Hetastarch maintained COP substantially higher than lactated Ringer's—approximately 2–3.2 mmHg greater at 30, 60 and 90 minutes—whilst also increasing plasma osmolality, though both fluids produced significant drops in total protein across all measured intervals. The findings suggest hetastarch 130/0.4 offers transient preservation of colloid osmotic pressure during the first 90 minutes of anaesthesia compared to an equivalent volume of crystalloid, which may help mitigate perioperative oedema and maintain perfusion pressure, particularly relevant for longer procedures or horses with compromised cardiovascular reserve. However, the protein-diluting effect common to both solutions and the lack of long-term outcome data mean these results should be integrated with individual patient assessment rather than viewed as definitive evidence for routine colloid use in equine anaesthesia.
Read the full abstract on PubMed
Practical Takeaways
- •Hetastarch may be superior to lactated Ringer's solution for maintaining colloid osmotic pressure during the first 90 minutes of equine general anaesthesia, potentially reducing oedema and improving tissue perfusion
- •Both fluids caused similar decreases in total protein; hetastarch's advantage is maintaining osmotic pressure, not protein preservation
- •Consider hetastarch for anaesthetised horses requiring fluid support during longer procedures to maintain better colloid osmotic pressure balance
Key Findings
- •Hetastarch 130/0.4 infusion for 60 minutes significantly increased plasma osmolality compared to lactated Ringer's solution at 30, 60, 90, and 120 minutes post-induction
- •Colloid osmotic pressure was significantly higher in the hetastarch group versus LRS group at 30 (18.8 vs 16.3 mmHg, P=0.001), 60 (19.1 vs 15.9 mmHg, P<0.0001), and 90 minutes (17.4 vs 15.4 mmHg, P=0.005)
- •Total protein decreased in both treatment groups at all time points after anaesthetic induction
- •Hetastarch transiently maintains colloid osmotic pressure better than an equivalent volume of lactated Ringer's solution during anaesthesia in horses