Innovations in postoperative pain management: continuous infusion of local anesthetics

AORN Journal,  May, 2007  by Angela Banks

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Both patients and their health care providers struggle with alleviating postoperative pain. The International Association for the Study of Pain defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. (1) Every patient has a unique perception of pain that requires an individualized plan for managing that pain.

Persistent pain has many detrimental effects. Patients with unrelieved pain are less likely to cough, breathe deeply, or move easily after surgery, which adversely affects the return of normal respiratory and gastrointestinal function. (2) Additionally, unrelieved pain increases the stress response of the immune system which leads to delayed wound healing and extended hospitalization. (2) There is no consensus on the best method for controlling pain, but because unrelieved pain results in numerous negative consequences that affect a patient's well-being, health care providers must stay abreast of current techniques used for postoperative pain management (Table 1). This article educates perioperative nurses and other health care providers about recent innovations in continuous local anesthetic infusion for postoperative pain management. Perioperative nurses who monitor patients preoperatively, intraoperatively, and postoperatively must be knowledgeable about this modern pain-relieving technique to optimize safety when providing patient care.

TRADITIONAL PAIN MANAGEMENT

Postoperatively, patients experience pain in response to tissue damage that triggers the release of prostaglandin, histamine, and serotonin. (3) Traditional treatment of postoperative pain primarily consists of parenteral administration of opioids. Unfortunately, opioids potentially can cause numerous adverse side effects, such as nausea, excessive sedation, and respiratory depression. (3) In an effort to avoid these potentially serious adverse effects, postoperative pain often is undertreated. Undermedicating leads to substantial patient discomfort and negative physiological changes to the respiratory, cardiovascular, gastrointestinal, urinary, musculoskeletal, and neuroendocrine systems. (3)

Local anesthetics have an opioid-sparing effect, so their use in conjunction with opioids significantly reduces the amount of opioids needed. (4) Combining local anesthetics and opioids constitutes a multimodal or balanced approach to pain management. (2) Taking a multimodal approach is important because decreasing the dose of opioids aids in minimizing or eliminating adverse side effects that may precipitate severe patient distress or even death. (4)

LOCAL ANESTHETIC INFUSIONS

Although debate concerning the best method to relieve pain remains contentious, recent innovations in technology are revolutionizing postoperative pain management. The concept of using local anesthetics for regional blockade was first described more than 50 years ago. (4) Renewed interest in continuous local anesthetic infusion for postoperative pain management has emerged in the past decade as a result of technological improvements in needles and catheter insertion techniques, effortless drug delivery systems, and increased interest in earlier discharge after surgery. (5) Local anesthetics prevent and alleviate pain by reversibly blocking the conduction of nerve impulses responsible for the sensation of pain. (4)

Continuous peripheral nerve blocks, also called perineural local anesthetic infusions, involve percutaneous insertion of a catheter directly against the peripheral nerves, which supplies the surgical site with continuous infusion of local anesthetics. (6) Continuous peripheral nerve blocks offer the benefit of prolonged analgesia with fewer adverse effects, increased patient satisfaction, and expeditious recovery after surgery. (7)

Local anesthetics may be used in a variety of clinical settings for treating mild to severe pain and may be administered via multiple routes: topically, intradermally, regionally, intraspinally, and as infusions that continuously bathe nerves. (4) For instance, in a rural southern Illinois hospital, certified RN anesthetists adopted the use of continuous nerve block technique because of great success in the management of patients' postoperative pain. According to Patrick Lillard, RN, MSN, CRNA (November 2006), patients report relief from pain without the adverse side effects of nausea and vomiting that are related to opioid administration. Lillard reports that his facility has used this innovative technique for approximately three years and performs roughly 200 continuous nerve blocks annually. He describes continuous infusion of local anesthetics for pain management as reliable and patient friendly.

THE AMBULATORY OUTPATIENT SETTING

Approximately 40% of surgical patients in ambulatory settings experience moderate to severe postoperative pain. (8) Uncontrolled patient pain in this setting leads to prolonged postanesthesia care unit (PACU) stays, severe pain after discharge, inability to perform activities of daily living, and unplanned hospital readmissions. (4)