What are the indications for intravenous (IV) fluid administration in pre-renal conditions, such as prerenal acute kidney injury (AKI) or impaired renal function?

From the Guidelines

Intravenous (IV) fluid therapy with isotonic crystalloids, such as normal saline or lactated Ringer's solution, is the primary treatment for pre-renal acute kidney injury, and should be administered at an initial rate of 500-1000 mL over 1-2 hours, followed by reassessment. The total volume depends on the patient's clinical status, with careful monitoring for fluid overload. For mild cases, 1-2 liters may be sufficient, while more severe dehydration might require 2-4 liters over 24 hours 1. During treatment, monitor vital signs, urine output, and kidney function tests (BUN, creatinine) every 4-6 hours. IV fluids work by restoring intravascular volume, improving renal perfusion, and enhancing glomerular filtration rate. This increases urine output and helps clear waste products. Underlying causes of pre-renal injury should be addressed simultaneously, such as stopping nephrotoxic medications, treating infections, or managing heart failure. In patients with heart or kidney failure, fluid administration must be more cautious to prevent volume overload.

Some key points to consider when administering IV fluids for pre-renal acute kidney injury include:

• Using isotonic crystalloids as the initial management for expansion of intravascular volume 1
• Avoiding the use of colloids, such as albumin or starches, unless absolutely necessary 1
• Monitoring for fluid overload and adjusting the rate and volume of IV fluids accordingly 1
• Addressing underlying causes of pre-renal injury, such as stopping nephrotoxic medications or treating infections 1
• Being cautious when administering fluids to patients with heart or kidney failure to prevent volume overload 1

It's also important to note that the use of 0.9% saline may induce a hyperchloremic metabolic acidosis, and large volumes may lead to abnormal fluid, electrolyte, and acid-base disturbances 1. However, the most recent and highest quality study available does not provide a clear alternative to 0.9% saline, and therefore it remains a commonly used option for IV fluid therapy in pre-renal acute kidney injury.

From the Research

IV Fluid Management in Prerenal Acute Kidney Injury

• The choice of IV fluid in patients with prerenal acute kidney injury (AKI) is crucial, as it can affect kidney function and overall outcome 2, 3.
• Normal saline (NS) and lactated Ringer's (LR) are two commonly used crystalloids in clinical practice, but they have different effects on acid-base balance and electrolyte levels 2, 4.
• A study comparing NS and LR in patients with prerenal AKI and pre-existing chronic kidney disease (CKD) found that LR had a better profile in acid-base balance improvement and chloride overload prevention 2.
• Another study suggested that isotonic crystalloids, such as LR, should be used instead of colloids for initial expansion of intravascular volume in patients at risk for AKI or with AKI 3.
• Fluid management in patients with cirrhosis and prerenal failure requires careful attention to renal perfusion and treatment of the underlying cause of hypoperfusion 5.
• The use of balanced crystalloids, such as LR, may offer an advantage over NS in the treatment of patients with acute diabetic ketoacidosis (DKA) and prerenal AKI 4.
• The principles of fluid resuscitation in the acutely ill, including the choice of IV solution and volume management strategies, are critical in preventing fluid toxicity and promoting kidney safety 6.