From the Guidelines
For patients with metabolic acidosis, the use of isotonic crystalloids like normal saline (0.9% NaCl) or balanced crystalloid solutions such as lactated Ringer's or Plasma-Lyte is recommended, with the choice depending on the specific cause of acidosis. The management of metabolic acidosis involves addressing the underlying cause while supporting circulation and preventing further acid accumulation. In cases of severe acidosis with pH < 7.1, sodium bicarbonate infusion may be considered, typically at a dose of 1-2 mEq/kg over 1-2 hours 1. However, the use of sodium bicarbonate is not universally recommended and its application should be cautious, especially in resource-limited settings where its use is advised against for metabolic acidosis arising from tissue hypoperfusion 1.
Key Considerations
- The primary goal is to treat the underlying cause of metabolic acidosis.
- Fluid resuscitation should be tailored to the patient's hydration status and the specific cause of acidosis.
- Balanced crystalloids are generally preferred over normal saline for most cases as they contain buffers like lactate or acetate that convert to bicarbonate, helping correct acidosis while avoiding hyperchloremia that can worsen acidosis.
- In lactic acidosis from poor perfusion, focus on fluid resuscitation with balanced crystalloids at 20-30 ml/kg.
- For diabetic ketoacidosis, begin with normal saline at 15-20 ml/kg in the first hour, then adjust to 250-500 ml/hr based on hydration status, while addressing the underlying cause with insulin.
Fluid Choice
- Isotonic crystalloids like normal saline (0.9% NaCl) or balanced crystalloid solutions such as lactated Ringer's or Plasma-Lyte are recommended.
- Avoid hypotonic fluids (e.g., glucose solutions) for fluid resuscitation 1.
- The choice of fluid should be based on the patient's specific needs and the cause of metabolic acidosis.
From the Research
Fluid Management in Metabolic Acidosis
The choice of fluid for patients with metabolic acidosis, particularly those with diabetic ketoacidosis (DKA), is crucial for effective management. Recent studies have compared the use of normal saline (NS) with balanced fluids such as Hartmann's solution (HS), lactated Ringers (LR), and Plasma-Lyte A solution.
Comparison of Normal Saline and Balanced Fluids
- A study published in the Journal of Paediatrics and Child Health 2 found that HS is an acceptable alternative to NS in DKA, particularly in severe cases, as it may reduce the risk of hyperchloremic metabolic acidosis.
- Another study in the Journal of Pharmacy Practice 3 concluded that balanced fluids (BF) are associated with a shorter time to DKA resolution compared to NS.
- A retrospective cohort study published in Cureus 4 suggested that large-volume resuscitation with isotonic NS is associated with increased ICU length of stay, prolonged insulin infusion, and a higher incidence of non-anion gap metabolic acidosis, supporting the use of balanced crystalloids like LR for initial resuscitation in DKA patients.
Clinical Effects of Balanced Crystalloids vs Saline
- A subgroup analysis of cluster randomized clinical trials published in JAMA Network Open 5 found that treatment with balanced crystalloids resulted in more rapid resolution of DKA and shorter time to insulin infusion discontinuation compared to saline.
- The study also suggested that balanced crystalloids may be preferred over saline for acute management of adults with DKA.
Recommendations for Fluid Management
- Based on the available evidence, balanced fluids such as HS, LR, or Plasma-Lyte A solution may be preferred over NS for initial fluid resuscitation in patients with DKA or metabolic acidosis 2, 3, 4, 5.
- However, the choice of fluid should be individualized based on the patient's specific needs and clinical status.