From the Guidelines

Hypophosphatemia in acute liver failure does require phosphate supplementation.

Electrolyte disturbances, such as serum phosphate, are commonly observed in patients with acute liver failure (ALF), and should be monitored and corrected 1.
In the context of nutritional support, liberal supplementation of phosphate is recommended, especially in the first two weeks, to prevent refeeding syndrome 1.
Hypophosphatemia can occur in patients with ALF, particularly in those with organ failure, and may require correction to prevent complications such as muscle weakness, respiratory failure, and cardiac dysfunction.
Although there are no specific guidelines for phosphate supplementation in ALF, the general principle of correcting electrolyte imbalances applies, and phosphate supplementation may be necessary to maintain normal phosphate levels.
It is essential to monitor phosphate levels closely and adjust supplementation accordingly to avoid both hypophosphatemia and hyperphosphatemia 1.

Phosphate supplementation should be individualized based on the patient's phosphate levels, renal function, and overall clinical condition.
The use of parenteral nutrition (PN) in patients with ALF may require careful monitoring of phosphate levels, as PN can contribute to hypophosphatemia 1.
In patients with ALF, it is crucial to balance the need for phosphate supplementation with the risk of hyperphosphatemia, which can occur in patients with renal dysfunction.

From the Research

Hypophosphatemia is a condition that can occur in patients with acute liver failure, and it may be associated with serious consequences such as cardiac and respiratory muscle contractility decrease, cardiac rhythm troubles, and cardiac arrest 2.
A study published in 1985 suggested that severe hypophosphatemia may be responsible for liver cell damage in patients with acute liver failure, as it impairs tissue oxygenation and depletes cellular ATP 3.

Phosphate supplementation is usually simple and can quickly restore regular concentrations, with few adverse effects when regularly used 2.
A study published in 2003 found that low serum phosphorus levels were associated with a better prognosis in patients with acute liver failure, and that phosphorus replacement was associated with a significant improvement in recovery in patients with low or normal serum phosphorus levels 4.
The management of hypophosphatemia involves calculating doses in millimoles rather than milligrams or milliequivalents to avoid potentially serious dosage errors, and monitoring serum phosphorus concentrations in patients at risk for hypophosphatemia 5.
Phosphate replacement can be given orally, intravenously, intradialytically, or in total parenteral nutrition solutions, and the rate and amount of replacement are empirically determined 6.

The treatment approach for hypophosphatemia depends on the severity of the condition, symptoms, and presence of comorbid conditions such as kidney failure, volume overload, hypo- or hypercalcemia, hypo- or hyperkalemia, and acid-base status 6.
Mild to moderate acute hypophosphatemia can usually be corrected with increased dietary phosphate or oral supplementation, while intravenous replacement is generally needed for severe hypophosphatemia or significant comorbid conditions 6.