The goal of this clinical trial is to test the impact of serum phosphorus level optimization on weaning from mechanical ventilation in adult ICU patients in Alexandria University Hospitals.

The main questions it aims to answer are:

• Does serum phosphorus level optimization affect the duration of mechanical ventilation?
• Is serum phosphorus level optimization associated with successful weaning from mechanical ventilation?

In critically ill patients, phosphorus supplementation is done using Sodium glycerophosphate pentahydrate solution.

Investigators will document patients' data in terms of independent variables and will randomly allocate the participants into one of the two study groups mentioned below.

• Control group, defined by maintaining serum phosphorus level at ≥ 2.5 and < 3.5 mg/dL.
• Intervention group, defined by optimization of serum phosphorus P to ≥ 3.5 and ≤ 4.5 mg/dL (Average 4mg/dL).

Regression and comparative statistics will be used to determine whether the optimum serum phosphorus level offers a benefit in terms of the duration of mechanical ventilation and the success of weaning from mechanical ventilation.

Inclusion Criteria:

• Adult mechanically ventilated ICU patients.
• Age ≥ 18 years.

Exclusion Criteria:

• Age <18 years
• Hypernatremia
• Permanent or prolonged mechanical ventilation
• Hyperphosphatemia which might occur in the following conditions:
• Chronic kidney disease and end stage renal disease
• Parathyroid disorders
• Cancer patients at risk of tumor lysis syndrome
• Immobility
• Body weight < 50 Kg