**Core Concept**
Total Infra–Venous Anaesthesia (TIVA) involves the administration of anaesthetic agents solely via the intravenous route, primarily using volatile agents and opioids, with no inhaled anaesthetics. It is known for its stable haemodynamic profile and consistent cerebral metabolic control, particularly in vulnerable populations like elderly or cardiac patients.

**Why the Correct Answer is Right**
TIVA maintains a stable and predictable cerebral metabolic rate (CMR), which is significantly reduced due to the absence of volatile anaesthetics that can cause cerebral vasodilation. This reduction in CMR is a key advantage of TIVA, especially in patients with pre-existing cerebrovascular disease or during prolonged surgeries. The mechanism involves suppression of neuronal activity and decreased cerebral blood flow, mediated by the combined effects of opioids and intravenous agents like propofol.

**Why Each Wrong Option is Incorrect**
Option A: TIVA does not cause more renal toxicity; in fact, it is associated with lower renal risk compared to volatile agents due to better perfusion and stable haemodynamics.
Option C: Malignant hyperthermia is a rare, life-threatening condition linked to volatile anaesthetics and succinylcholine, not intravenous agents like propofol or opioids. TIVA has a significantly lower risk of this event.
Option D: Hypoxic pulmonary vasodilation is preserved in TIVA, as intravenous agents do not suppress pulmonary vascular tone. In fact, TIVA may support better pulmonary perfusion than volatile anaesthesia.

**Clinical Pearl / High-Yield Fact**
TIVA reduces cerebral metabolic rate by 30–50%, making it ideal for patients at risk of cerebral ischemia or during prolonged surgeries. This effect is especially valuable in cardiac or neurosurgical procedures.

✓ Correct Answer: B. Reduces Cerebral Metabolic Rate