Epidural or intrathecal injection of local anesthetic with or without opioid can control postoperative pain. Lumbar epidural placement can be used for postoperative pain control following major abdominal, pelvic, or lower extremity surgeries. Epidural medication can also be introduced via a catheter through the sacrococcygeal membrane using a caudal technique for groin, pelvic, or lower extremity surgeries. Thoracic epidurals can be used to control pain after thoracic surgery, upper and lower abdominal surgery, and multiple rib fractures. Useful landmarks to help approximate the puncture site are the C7 spinous process, the scapular spine (T3), and the inferior border of the scapula (T7).
Epidural analgesia has been shown to decrease the incidence of venous and pulmonary thromboembolism, limit cardiac complications due to increased coronary blood flow, and improve myocardial oxygen balance. Epidural analgesia reduces the incidence of postoperative pneumonia, atelectasis, and respiratory depression. Patients also require less parenteral opioids, which decrease the risk of postoperative ileus and results in earlier return of gastrointestinal function.
Contraindications to Neuraxial Blockade
Since neuraxial blockade requires the cooperation of an “awake” patient, neuraxial blockade is contraindicated with uncooperative patients. In some cases, an exception may be made to perform neuraxial blockade under anesthesia. Local infection at the site of spinal or epidural placement is another contraindication. Spinal and epidural anesthesia frequently results in sympathetic blockade and subsequent hypotension. Therefore, neuraxial blockade should be avoided in patients with severe hypovolemia, sepsis, or aortic stenosis in which a precipitous reduction in afterload would exacerbate cardiac dysfunction. There is a risk of brainstem herniation in patients with increased intracranial pressure who receive neuraxial blockade; therefore, increased intracranial pressure should negate consideration of neuraxial blockade. Coagulopathy is a contraindication to neuraxial blockade due to the risk of neuraxial hematoma formation. It is important to check platelet levels, noting absolute number, rate of change, conditions that may affect platelet quality (ie, preeclampsia), and any anticoagulant medications or herbal remedies the patient is taking to properly assess for coagulopathy.
Anticoagulation and Neuraxial Blockade
Patients are frequently placed on anticoagulation while in the hospital for thromboprophylaxis. It is always important to document when a patient last received anticoagulation as there is a possible risk of neuraxial hematoma. The American Society of Regional Anesthesia and Pain Medicine’ s guidelines summarize the anticoagulation status and when to safely perform or discontinue neuraxial blockade.
Adjuncts to Local Anesthetic
Vasoconstrictors, such as epinephrine, can be added to the local anesthetic injectate. They help to decrease the uptake of the local anesthetic, thereby increasing the duration and density of the blockade.
Opioids can also be added to local anesthetic or can be the sole agent used for pain control. The most commonly used opioids are morphine and fentanyl. The time of onset and duration of action relates ...