Epidural administration (from Ancient Greek ἐπί, , upon dura mater) is a method of medication administration in which a medicine is injected into the epidural space around the spinal cord. The epidural route is used by physicians and nurse anesthetists to administer local anesthetic agents, analgesics, diagnostic medicines such as radiocontrast agents, and other medicines such as glucocorticoids. Epidural administration involves the placement of a catheter into the epidural space, which may remain in place for the duration of the treatment. The technique of intentional epidural administration of medication was first described in 1921 by Spanish military surgeon Fidel Pagés. In the United States, over 50% of childbirths involve the use of epidural anesthesia.
Epidural anaesthesia causes a loss of sensation, including pain, by blocking the transmission of signals through nerve fibres in or near the spinal cord. For this reason, epidurals are commonly used for pain control during childbirth and surgery. The technique is considered safe and effective for providing pain relief during childbirth and surgery, and is considered more effective and safer than giving pain medication by mouth or through an intravenous line. An epidural injection may also be used to administer steroids for the treatment of inflammatory conditions of the spinal cord. It is not recommended for people with severe bleeding disorders, low platelets, or infections near the intended injection site. Severe complications from epidural administration are rare, but can include problems resulting from improper administration, as well as side effects of the medicines administered. The most common complications of epidural injections include bleeding problems, headaches, and inadequate pain control. Epidural analgesia during childbirth may also impact the mothers ability to move during labor. Very large doses of anesthetics or analgesics may result in respiratory depression.
An epidural injection may be administered at any point of the spine, but most commonly the lumbar spine, below the end of the spinal cord. The specific administration site determines the specific nerves affected, and thus the area of the body from which pain will be blocked. Insertion of an epidural catheter consists of threading a needle between bones and ligaments to reach the epidural space without going so far as to puncture the dura mater. Saline or air may be used to confirm placement in the epidural space. Alternatively, direct imaging of the injection area may be performed with a portable ultrasound or fluoroscopy to confirm correct placement. Once placed, medication may be administered in one or more single doses, or may be continually infused over a period of time. When placed properly, an epidural catheter may remain inserted for several days, but is usually removed when the use of less invasive administration methods (such as taking medication by mouth) is a viable alternative.
