High spinal anaesthesia is associated with?
**Core Concept**
High spinal anaesthesia refers to the accidental injection of local anaesthetic into the subarachnoid space above the level of the conus medullaris, leading to motor and sensory blockade of the lower limbs. This condition can cause significant morbidity due to respiratory and cardiovascular instability.
**Why the Correct Answer is Right**
High spinal anaesthesia is associated with autonomic dysfunction, characterized by hypotension, bradycardia, and respiratory depression. The blockade of sympathetic nerves in the spinal cord leads to vasodilation and a decrease in vascular tone, resulting in hypotension. Additionally, the blockade of parasympathetic nerves can cause bradycardia. The respiratory depression is due to the blockade of phrenic nerves, which can lead to respiratory failure.
**Why Each Wrong Option is Incorrect**
**Option A:** Vasopressor resistance is incorrect because high spinal anaesthesia is associated with vasodilation and hypotension, not vasopressor resistance.
**Option B:** Hyperthermia is incorrect because high spinal anaesthesia is associated with sympathetic blockade, leading to vasodilation and hypotension, not hyperthermia.
**Option C:** Seizures are incorrect because high spinal anaesthesia is not typically associated with seizures. Seizures can occur with local anaesthetic systemic toxicity, but this is a different condition.
**Clinical Pearl / High-Yield Fact**
Remember that high spinal anaesthesia is a medical emergency that requires immediate recognition and treatment. The key to management is to maintain respiratory and cardiovascular stability with supportive measures and vasopressors as needed.
**Correct Answer: A. Autonomic dysfunction**