The reversible and controlled induction of loss of motor and sensory function through the injection of local anesthetics into the epidural space is referred to as epidural anesthesia. This mode of anesthesia can be administered via an injector or catheter. The latter allows for the continuous addition of the local anesthetic throughout a surgical procedure and after it, to relieve postoperative pain as well.
Surgical procedures below the level of the umbilicus are prime indications for epidural anesthesia. These include, but are not limited to, Cesarean section, repair of hernias, orthopedic operations involving the lower extremities, as well as gynecological and genitourinary procedures.
Epidural nerve block. Image Credit: ChaNaWiT / Shutterstock
Advantages and Disadvantages
Epidural anesthesia is a procedure that is fairly easy to perform and, in most cases, highly reliable with regard to the extent and control of anesthesia. In contrast to general anesthesia, there is no respiratory depression and the patient maintains spontaneous ventilation without the need for mechanical assistance.
Furthermore, and in comparison to general anesthesia, studies show that there is a decreased incidence of complications, such as thrombosis of the deep veins and/ or the formation of pulmonary emboli, with epidural anesthesia.
Additionally, patients often experience a faster recovery with regard to the functioning of the gastrointestinal system.
Among the disadvantages, epidural anesthesia has a slower onset and typically requires a larger dose for the onset of action than its spinal counterpart.
This means that it is imperative to monitor dosage, because toxicity can more easily and inadvertently occur with epidural anesthesia.
Likewise, the rate of failure to achieve anesthesia is higher with epidural than it is with spinal anesthesia.
Some patients may experience headache based on their position following management with epidural anesthesia. This may occasionally require further treatment to speed up the resolution process.
Another minor complication is post-epidural discomfort, which is injection-site specific. This is generally self-limited and resolves quickly.
During Labor and Delivery
Epidural anesthesia is given to an expectant mother during the process of labor and the delivery of the baby if desired. It is the preferred method in women who are in premature labor or those who are suffering from preexisting morbidities such as hypertension. Epidural anesthesia is safe for both the mother and the child.
The local anesthetics are injected into the epidural space, with the help of bony vertebral landmarks, during the active stage of labor.
These agents block pain signals from being transmitted to the brain. Within a few minutes, the parturient (i.e. the woman in labor) no longer feels any pain associated with labor.
Local anesthetics are re-administered as necessary through a catheter indwelling the epidural space if the duration of the labor is prolonged.
Once the baby has arrived, the epidural catheter is removed and the anesthetic effects typically wear off within an hour or two. Many patients may experience burning at this time around and inside the birth canal.