SPINAL ANESTHESIA

Definition:

Spinal anaesthesia is a type of regional anaesthesia.

injecting a local anaesthetic into the subarachnoid space, specifically into the cerebrospinal fluid (CSF), to block nerve impulses, resulting in the loss of sensation and motor function in the lower part of the body.

Procedure:

Positioning: The patient is typically positioned in a sitting or lateral decubitus position.

 Site of Injection: The injection is usually performed at the lumbar level, between the L3-L4 or L4-L5 intervertebral spaces, to avoid damage to the spinal cord.

Needle: A small-gauge spinal needle is used to pierce the dura mater and reach the subarachnoid space.

Local Anaesthetic: Commonly used agents include bupivacaine, lidocaine, and ropivacaine. The anaesthetic mixes with the CSF, providing a dense and rapid block.

Indications:

Surgeries involving the lower abdomen, pelvis, perineum, and lower limbs (e.g., caesarean section, hernia repair, lower limb orthopaedic surgery).

Advantages:

Rapid onset of anaesthesia.

Good muscle relaxation.

Reduced systemic drug load compared to general anaesthesia.

Lower incidence of postoperative nausea and vomiting.

Patient remains conscious, which can be beneficial in certain surgeries.

Complications:

Hypotension: Due to sympathetic block leading to vasodilation.

Post-Dural Puncture Headache (PDPH): Caused by leakage of CSF (Cerebrospinal fluid) through the puncture site.

Bradycardia: Due to blockade of sympathetic cardiac fibers.

Urinary Retention: Temporary, due to blockade of autonomic nerves.

Neurological Complications: Very rare, but may include nerve damage or infection.

Contraindications:

Patient refusal.

Infection at the injection site.

Coagulopathy or anticoagulant therapy.

Severe hypovolemia.

Increased intracranial pressure.

Allergy to local anaesthetic agents.

Recovery:

 

The effects of spinal anaesthesia typically wear off after a few hours, depending on the agent used.

Patients are monitored until sensation and motor function return, and any side effects (like hypotension) are managed.