From the Guidelines
The most common complication of epidural analgesia is hypotension. When local anesthetics are administered into the epidural space, they block sympathetic nerve fibers that maintain vascular tone, leading to vasodilation and decreased peripheral vascular resistance. This vasodilation causes blood to pool in the peripheral vessels, reducing venous return to the heart and subsequently decreasing cardiac output, which manifests as hypotension. The incidence of hypotension varies but can occur in up to 33.6% of patients receiving epidural analgesia, depending on factors such as the concentration and volume of local anesthetic used, the level of insertion, and patient characteristics 1. Hypotension typically develops within 20-30 minutes after administration and can be managed by intravenous fluid administration, positioning the patient, and occasionally vasopressors if severe. While other complications like nausea, respiratory depression, and deep vein thrombosis can occur with epidural analgesia, they are less common than hypotension. A recent meta-analysis comparing epidural vs. systemic analgesia in patients undergoing abdominal and thoracic surgery found that epidural analgesia was associated with a significant decrease in odds of pneumonia and improved lung function, but increased the risk of hypotension, urinary retention, and pruritus 1. Key points to consider when managing epidural analgesia include:
- Confirming euvolemia and adding a vasopressor before administering further intravenous fluid if a patient with a TEA is hypotensive 1
- Monitoring patients receiving spinal morphine closely for the first 24 h due to the risk of delayed respiratory depression 1
- Using alternative analgesic techniques in MIS surgery, such as spinal analgesia, abdominal wall blocks, wound infusion catheters, lidocaine infusion, intraperitoneal local anesthetic, and wound infiltration 1.
From the Research
Complications of Epidural Analgesia
- The most common complication of epidural analgesia is hypotension, as stated in the studies 2, 3, and 4.
- Hypotension is largely the result of sympathetic nerve blockade, which can lead to excessive hypotension and potentially produce myocardial and cerebral ischemia 2.
- Other complications of epidural analgesia include motor block, dural tap, ineffective pain control, accidental catheter pull outs, and problems associated with the delivery system of the drug 5.
- Unintentional dural puncture (UDP) is also a common complication, which can lead to post-dural puncture headache (PDPH) 6.
Management of Hypotension
- Vasopressor agents, such as ephedrine, are commonly used to manage hypotension induced by spinal and epidural anesthesia 2.
- Fluid preloading with colloids, such as hydroxyethyl starch, can effectively reduce the incidence and severity of arterial hypotension 4.
- Co-loading with crystalloid or colloid is also effective, provided that the speed of administration is adequate 4.
- Phenylephrine, a α1 adrenergic receptor agonist, is increasingly used to treat hypotension and its prophylactic administration can decrease the incidence of arterial hypotension 4.