Guidelines for Spinal, Epidural, and Combined Spinal‑Epidural Anaesthesia

Epidural Anaesthesia Characteristics

Higher total doses of local anaesthetic are required for epidural compared with spinal anaesthesia, resulting in a slower onset and less effective sacral block. 4
Epidural catheters permit incremental dosing and prolonged anaesthesia, allowing flexibility for extended surgical procedures. 5

The needle‑through‑needle CSE approach is more reliable than epidural alone because free flow of cerebrospinal fluid confirms correct midline placement in the epidural space. 4
CSE enables a small‑dose spinal injection for rapid onset while the epidural catheter provides a backup for extension or prolongation of the block when needed. 6

Inadvertent high neuraxial block that necessitates cardiovascular and/or respiratory support occurs in approximately 1 per 4,367 spinal anaesthetics. 8
Early clinical signs of a high block include increasing agitation, marked hypotension, bradycardia, upper‑limb weakness, dyspnoea, or difficulty speaking. 8
Management of a high block should include administration of vasopressors, fluid resuscitation, supplemental oxygen, and, when required, tracheal intubation with mechanical ventilation. 8
Failure to aspirate cerebrospinal fluid from an intrathecal catheter does not rule out subarachnoid placement; catheters may also migrate over time. 8
Accidental delivery of epidural‑dose volumes through an intrathecal catheter has been reported to cause high/total spinal blocks, respiratory arrest, and cardiac arrest. 8
Block height must be reassessed at least every 5 minutes until no further cephalad extension is observed. 8

Standard intra‑operative monitoring for spinal anaesthesia should include continuous pulse oximetry, electrocardiography, and non‑invasive blood pressure measurement. 2
Supplemental oxygen should be administered throughout the spinal anaesthetic technique. 2
Absolute contraindications: documented coagulopathy or therapeutic anticoagulation, and patient refusal. 2
Relative contraindications: infection at the injection site, elevated intracranial pressure, and significant hypovolemia. 2

Epidural failure is identified by the absence of sensory and motor block together with a lack of expected haemodynamic changes, suggesting catheter misplacement outside the epidural space. 3
Prior to induction, a test dose using cold or pin‑prick stimulation should confirm bilateral sensory block to at least the T10 dermatome for abdominal surgery. 3