## Core Concept
Total parenteral nutrition (TPN) provides essential nutrients intravenously to patients who cannot receive feedings or fluids by mouth. It is a complex therapy that can lead to various metabolic complications if not managed properly. These complications can arise due to the composition of the TPN solution, the patient's underlying health status, and their individual metabolic needs.

## Why the Correct Answer is Right
The correct answer involves identifying which of the listed options are likely metabolic complications of total parenteral nutrition within the first two weeks of therapy.
- **Hyperosmolar non-ketotic hyperglycaemia (b)**: This condition can occur due to the glucose load in TPN, especially if the patient has diabetes or insulin resistance. High glucose levels can lead to osmotic diuresis and potentially life-threatening dehydration and hyperosmolarity.
- **Hypophosphataemia (d)**: This is a common complication, especially during the initiation of TPN. As cells begin to receive adequate nutrition and anabolic processes increase, phosphate is taken up by cells, which can lead to decreased serum phosphate levels. Hypophosphatemia can cause muscle weakness, respiratory failure, and cardiac dysfunction.

## Why Each Wrong Option is Incorrect
- **Option A: Cardiopulmonary failure**: While cardiopulmonary issues can arise in the context of severe metabolic disturbances caused by TPN, cardiopulmonary failure itself is more of a consequence of severe, untreated metabolic complications rather than a direct metabolic complication of TPN.
- **Option C: Zinc deficiency**: Although zinc deficiency can occur with TPN, especially if the formulation is not adequately supplemented, it is less likely to present as an acute complication within the first two weeks. Zinc deficiency typically manifests with skin lesions, diarrhea, and immune dysfunction over a longer period.

## Clinical Pearl / High-Yield Fact
A key point to remember is that when initiating TPN, it is crucial to monitor serum electrolytes, glucose, and liver function tests closely to prevent and manage metabolic complications. The refeeding syndrome, which includes hypophosphatemia, hypokalemia, and hypomagnesemia, is a particularly important concern when starting TPN in malnourished patients.

## Correct Answer: D.