Complications of epidural anesthesia

What is Epidural Anesthesia

Epidural anesthesia is the anesthesia which blocks the pain in specific area of the body. The drugs that are administered have the goal to reduce the pain and sensations in the lower part of the body. As any other form of anesthesia epidural anesthesia carries certain risks. The most frequent side effect of the epidural anesthesia is the hypotension. The hypotension is corrected with fluids and vasopressors which are given intravenously.

If excessive dosage of local anesthetics is given to inadvertent then the high epidural block may develop. Its features are with the low blood pressure, nausea, loss of sensation in chest region or even in an arms. This severe complication can even affect the breathing. The outcome may include securing of the airway and prompt treatment of hypotension.

Risks of Epidural Anesthesia

Local anesthetic toxicity may develop as a consequence of surpassing of the dose of anesthetics. Toxicity may happen even in case when proper dose is not given but straight into a blood vessel. This condition can be present with ringing in the ears, dizziness or even lead to coma and cardiopulmonary arrest.

An accidental dural puncture may happen during the procedure of applying epidural anesthetics. It results in headache which is basically in the front of the skull. The pain is increased by movements or in a sitting or standing position. Nausea and vomiting may occur as well. Photophobia or sensitivity to light in a common sign.

Epidural anesthesia is a versatile technique widely used in anesthetic practice. Its potential to decrease postoperative morbidity and mortality has been demonstrated by numerous studies. To maximize its perioperative benefits while minimizing potential adverse outcomes, the knowledge of factors affecting successful block placement is essential. This paper will provide an overview of the pertinent anatomical, pharmacological, immunological, and technical aspects of epidural anesthesia in both adult and pediatric populations and will discuss the recent advances, the related rare but potentially devastating complications, and the current recommendations for the use of anticoagulants in the setting of neuraxial block placement.

The epidural space extends from the base of the skull to the sacral hiatus. Its lateral boundaries are the vertebral pedicles, while the anterior and posterior boundaries are the dura mater and ligamentum flavum, respectively. The contents of the space include fat, lymphatics, and veins with nerve roots that cross it. Determinants of epidural fat include age and body habitus with obese patients having the greatest amount of epidural fat. The amount of epidural fat within the space is just one of the factors that determine volume necessary for adequate anesthesia or analgesia.
Traditional thought on epidural anatomy was that it is one continuous space. A more recent thought is the concept of it being a potential space with septations or crevices formed by layering of epidural contents (fat). The anatomic layering and texture of epidural contents create inconsistent paths that ultimately make flow through it less uniform. The idea of these septations or crevices forming variable paths for the flow of a solution is the rationale given for unilateral or partial epidural blockade.
Lidocaine has traditionally been the agent of choice for slightly longer surgical procedures that require an intermediate-acting local anesthetic. In place of lidocaine, some centers have also adopted the use of mepivacaine for its longer length of action with a similar onset profile. The intermediate length of action of either agent can be prolonged by the addition of epinephrine. Of note is the potential for an increased incidence of hypotension due to venous pooling from the beta effects of epinephrine containing solutions. This phenomenon seems to be especially true of patients receiving lumbar epidural analgesia.
Epidural anesthesia and analgesia are generally considered to be safe with regards to adverse post procedural events, as their complications, resulting in permanent deficits, are rare. Besides their indications and obvious benefits, knowledge of adverse outcomes should also comprise an essential part of clinical decision making.
Complications of central neuraxial blockade, much depending on the experience in patient management, as well as materials, equipment, and the presence of risk factors, have been reported to occur at various frequencies. An epidemiologic study conducted in Sweden over a period of 10 years revealed an increasing trend (1 in 10,000 neuraxial anesthetics) of severe complications after central neuraxial blockade. Relatively recent literature suggests that most of these occur with the perioperative use of epidural block. The incidence of major complications (permanent harm including death) of epidural and combined spinal-epidural anesthesia were at least twice as high as those of spinal and caudal blocks, as reported by Cook and colleagues.
Complications may occur early if related to traumatic catheter insertion, or later in the operative-postoperative course if caused by catheter-related spinal space-occupying lesions such as epidural hematoma or abscess formation, and are infrequent among the general population. Although its incidence is lower than when associated with spinal anesthesia, transient neurological injury has been found to account for the majority of short-term epidural catheter related complications (1 in 6,700) in a meta-analysis by Ruppen and colleagues, followed by deep epidural infections (1 in 145,000), epidural hematoma (1 in 150,000–168,000), and persistent neurological injury (1 in 257,000) in women receiving epidural catheter for childbirth. Spinal epidural hematoma, however, has been recently suggested to occur in a rate as high as 1 in 3,600 in female patients undergoing knee arthroplasty.

Epidural and caudal anesthesia is a versatile neuraxial anesthetic technique with an expanding area of indication. It can be used in the perioperative setting as the sole anesthetic, or in combination with general or spinal anesthesia. Its potential to decrease postoperative complication rate by its beneficial physiological effects has been clearly demonstrated in several studies. The absolute contraindications to its use have traditionally been well defined. Despite its rare, but potentially devastating complications, neuraxial anesthesia is considered to be safe. Performing such procedures in the presence of anticoagulants is however controversial. With patients presenting with medical conditions that predispose to clinically significant bleeding and an increased number of patients taking various anticoagulants, there is greater concern for an increased incidence of epidural hematomas.

✓ Fact confirmed: Recent Advances in Epidural Analgesia Maria Bauer, John E. George, III, John Seif, and Ehab Farag; 2011 Nov 24.