The Role of Non-Opioid Analgesic Techniques in the Management of Pain After Ambulatory Surgery

In describing how patients feel after surgery, Armitage (1) stated that “slapping the patient on the face and telling him or her that it’s all over is a complete inversion of the truth” because as far as the patient is concerned, “it is often just the beginning.” Although the current armamentarium of analgesic drugs and techniques is impressive, effective management of postoperative pain still poses some unique challenges in the ambulatory setting. The increasing number and complexity of operations being performed on an outpatient basis has presented anesthesia practitioners with new challenges with respect to acute pain management. Outpatients undergoing day-care procedures require a perioperative analgesic technique that is effective, has minimal side effects, is intrinsically safe, and can be easily managed away from the hospital or surgery center. The adequacy of postoperative pain control is one of the most important factors in determining when a patient can be safely discharged from the outpatient facility (2). Because inadequately treated pain is a major cause of prolonged stays or unanticipated hospital admissions after ambulatory surgery, the ability to provide effective pain relief by simple methods that are readily available to an outpatient in his or her home environment will be one of the major challenges for providers of ambulatory anesthesia in the future (3). Unfortunately, there are very few well controlled studies that have carefully examined the optimal approaches to managing postdischarge pain after outpatient surgery. Perioperative analgesia has traditionally been provided by opioid analgesics. However, the use of large doses of opioids during ambulatory surgery can be associated with an increased incidence of postoperative complications (e.g., ventilatory depression, sedation, postoperative nausea and vomiting, pruritus, difficulty voiding, and ileus), which in turn contribute to a delayed discharge from the day-surgery facility or to unanticipated hospital admissions. The intraoperative use of large bolus doses or continuous infusions of potent short-acting opioid analgesics (e.g., alfentanil and remifentanil) may actually increase postoperative pain as a result of their rapid elimination and the development of acute tolerance (4). Therefore, anesthesiologists practicing in the ambulatory environment are increasingly using non-opioid analgesics as adjuvants during the perioperative period (Table 1).Table 1: Commonly Used Non-Opioid Drugs and Nonpharmacologic Techniques for Minimizing Pain After Ambulatory SurgeryTo minimize the adverse effects of analgesic medications, “balanced” analgesic techniques involving the use of smaller doses of opioids in combination with non-opioid analgesic drugs (e.g., local anesthetics and nonsteroidal antiinflammatory drugs [NSAIDs]) are becoming increasingly popular approaches during and after ambulatory surgery (5,6). The rationale for the perioperative use of non-opioid analgesic drugs and techniques in the ambulatory setting will be reviewed in this article. Local Anesthetic Techniques Peripheral nerve blocks and wound infiltration with local anesthetics are commonly used adjuvants to both monitored anesthesia care (MAC) and general anesthetic techniques because they can provide intra- and postoperative analgesia (Table 2). As a result, these techniques can decrease the anesthetic and analgesic requirements during surgery and reduce the need for opioid analgesics in the postoperative period. More effective pain relief in the early postoperative period from the residual sensory block provided by local anesthesia can facilitate the recovery process, enabling earlier ambulation and discharge home (i.e., fast-tracking). The use of local anesthetic techniques also decreases the incidence of postoperative nausea and vomiting and thereby decreases the incidence of prolonged recovery stays and unanticipated hospital admissions related to intractable emetic symptoms.Table 2: Commonly Used Techniques for Administering Local Anesthesia During Ambulatory SurgeryAlthough additional clinical studies are needed to identify the most cost-effective anesthetic techniques for ambulatory surgery, it would seem that peripheral nerve blocks with sedation (i.e., MAC techniques) offer significant advantages over central neuraxis blockade and general anesthesia in the ambulatory setting (7–9). In outpatients undergoing saphenous vein-stripping surgery, use of a femoral/genitofemoral nerve block significantly improved patient satisfaction with the anesthetic experience (7). Blockade of the ilioinguinal and iliohypogastric nerves can significantly decrease the anesthetic and analgesic requirements in both children and adults undergoing inguinal herniorrhaphy, providing 6–8 h of postoperative analgesia (10,11). Similarly, subcutaneous ring block of the penis provides effective perioperative analgesia for circumcision procedures (12). Local anesthetic infiltration of the mesosalpinx significantly decreases the pain and cramping after laparoscopic tubal ligation procedures (13). Pain after arthroscopic shoulder surgery was decreased significantly by a simple suprascapular nerve block (14), and pain after knee surgery was minimized with a femoral nerve block (15). However, more complete perioperative analgesia for shoulder and knee surgery requires the use of an interscalene brachial plexus block (16) and combined femoral, obturator, lateral femoral cutaneous, and sciatic nerve (17) blocks, respectively. Although additional preparation time may be required when these major peripheral nerve blocks are performed before surgery, these block techniques can offer advantages in the postoperative period compared with general or spinal anesthesia (16,17). It has been suggested that performing neural blockade with local anesthetics before the surgical incision may prevent the nociceptive input from altering the excitability of the central nervous system (e.g., preemptively blocking the N-methyl-d-aspartate-induced “wind up” phenomena and release of inflammatory mediators) (18). The concept of preemptive analgesia (or treating postoperative pain by preventing the establishment of central sensitization) seems very logical (18); however, its clinical relevance has been questioned. Only one well controlled study has demonstrated any benefits of pre- versus postincisional local anesthetic administration in the ambulatory setting (19). A recent qualitative and quantitative review by Møiniche et al. (20) suggested that evidence is still lacking that the timing of single-dose or continuous postoperative pain treatment is important in the management of postsurgical pain. These investigators concluded that there is no convincing evidence that preemptive treatment with centrally or peripherally administered local anesthetics, NSAIDs, opioid analgesics, or ketamine offers any advantage with respect to postoperative pain relief compared with a similar postsurgical analgesic regimen. Nevertheless, preincisional administration offers advantages over infiltration at the end of surgery with respect to intraoperative analgesia. Preincisional infiltration with local anesthetics in combination with general anesthesia is clearly superior to general (or spinal) anesthesia alone in relieving postoperative pain (21,22). In fact, preincisional infiltration of the tonsillar bed with bupivacaine decreased both constant pain and pain on swallowing for up to 5 days after tonsillectomy procedures in children (22). Preincisional ilioinguinal hypogastric nerve block not only improves intraoperative pain control during inguinal hernia repair, but also reduces the need for oral opioid-containing analgesics after discharge (23). Although preincisional infiltration of the operative site with local anesthetics remains a popular technique for reducing the perioperative opioid analgesic requirement, other more simplified local anesthetic delivery systems (e.g., topical applications) have also been described in the anesthesia literature (24,25). Topical analgesia with lidocaine aerosol was found to be highly effective in decreasing pain, as well as the opioid analgesic requirement, after inguinal herniorrhaphy in adults (24), and instillation of 0.25% bupivacaine before surgical closure provided comparable postoperative pain relief to an ilioinguinal/iliohypogastric nerve block in children undergoing hernia repair (25). Furthermore, the simple application of topical lidocaine jelly or ointment is as effective as peripheral nerve blocks or parenteral opioids in providing pain relief after outpatient circumcision (26). Intracavitary instillation of local anesthetics is another simple, yet effective, technique for providing pain relief during the early postoperative period after laparoscopic and arthroscopic procedures. Intraperitoneal administration of local anesthetics during laparoscopy was found to be an efficient method of reducing the intensity of postoperative scapular pain (27). However, when bupivacaine was injected at the preperitoneal fascial plane during extraperitoneal laparoscopic hernia repair, it did not reduce postoperative pain (28). Local anesthetics can also be injected into joint spaces to provide analgesia during and after arthroscopic surgery (29). In a placebo-controlled study, intraarticular instillation of 30 mL of 0.5% bupivacaine reduced the opioid requirements and facilitated early mobilization and discharge after knee arthroscopy (30). A follow-up study (31) involving a combination of intraarticular bupivacaine and systemic ketorolac (60 mg IV or IM) further decreased pain in the early postoperative recovery period. A wide variety of adjuvants has also been injected into the intraarticular space to decrease postarthroscopic pain, including morphine, ketorolac, triamcinolone, and clonidine (32–35). Small-dose intraarticular morphine 1–3 mg, in combination with bupivacaine, seems to provide the longest lasting and most cost-effective analgesia after knee arthroscopy (36,37). Although administering the intraarticular morphine before knee surgery was reported to provide a longer duration of analgesia and greater opioid-sparing effects than when it was given at the end of surgery (37), the clinical advantages of preemptive analgesia remain controversial (20). Local anesthetic supplementation clearly decreases the severity of incisional pain in the early postoperative period. However, outpatients may still experience significant pain after they have been discharged home because of difficulty in anticipating the degree of pain when the local anesthetic effect wears off. Continuous (38,39) or intermittent perfusion (40) of the surgical wound with local anesthetic solutions is an old-fashioned but highly effective technique for extending incisional pain relief into the postdischarge period. Recently, this technique has been modified to allow for patient-controlled local anesthetic administration after discharge home (41). However, some investigators have failed to find significant differences in pain scores or opioid analgesic requirements when the local anesthetic was instilled or injected at the incision site (42,43). The response to local analgesia appears to be influenced by the location, concentration, and volume of the injected local anesthetic solution. For example, Yndgaard et al. (44) demonstrated that subfascially administered lidocaine was significantly more effective in reducing pain compared with subcutaneous injection after inguinal herniotomy. Finally, combining local anesthetic techniques with other analgesic modalities as part of multimodal (or “balanced”) analgesic therapy can improve pain control throughout the perioperative period (45). The concept of balanced analgesia consists of administering several different analgesic drugs to alter the pathophysiologic processes involved in nociception, thereby producing more effective perioperative analgesia with fewer side effects (5,6). In summary, local anesthetic wound infiltration and peripheral nerve block techniques are simple, safe, and effective approaches to providing perioperative analgesia in the ambulatory setting. Use of major neural blockade techniques involving the upper (e.g., interscalene brachial plexus block) and lower (e.g., femoral nerve block) extremities can facilitate an earlier discharge after major shoulder and knee reconstructive procedures, respectively (46,47). The availability of newer local anesthetic drugs that are alleged to be associated with less toxicity and greater selectivity with respect to sensory and motor blockade (e.g., ropivacaine and levobupivacaine) may further enhance the benefits of local anesthetic supplementation after ambulatory surgery. The addition of adjuvants (e.g., clonidine) can prolong the postoperative analgesia produced by peripheral nerve blocks (48). Recent studies by Klein et al. (49,50) suggest that improved pain control could also be achieved after major shoulder and knee procedures by using a disposable, nonelectronic catheter system for continuously infusing local anesthetic solutions. However, additional studies are needed to document the alleged advantages of these newer local anesthetic drugs and techniques. Future studies are also needed to determine the optimal local anesthetic concentrations and infusion rates with the new catheter systems. NSAIDs NSAIDs have long been used for treating nonsurgical pain syndromes because of their well known antiinflammatory, antipyretic, and analgesic properties. However, with the introduction of parenteral preparations of NSAIDs (e.g., ketorolac and diclofenac), these drugs have become more popular in the management of pain associated with ambulatory surgery. NSAIDs block the synthesis of prostaglandins by inhibiting the enzyme cyclooxygenase (COX), thereby reducing the production of mediators of the acute inflammatory response. By decreasing the inflammatory response to surgical trauma, NSAIDs have been alleged to reduce peripheral nociception. However, more recent studies also suggest that the central response to painful stimuli may be modulated by NSAID-induced inhibition of prostaglandin synthesis in the spinal cord (20). Early reports suggested that NSAIDs possessed analgesic properties comparable to those of opioid analgesics (51–53) without opioid-related side effects (54,55). When ketorolac was administered as an adjuvant to propofol/nitrous oxide anesthesia, its use was associated with improved postoperative analgesia and patient comfort, which compared favorably to fentanyl (55). Moreover, ketorolac was associated with a decreased incidence of postoperative nausea and vomiting, and patients tolerated oral fluids and were judged fit for discharge earlier than those receiving opioid compounds. Other investigators have also reported that ketorolac provided similar postoperative pain relief to that of fentanyl but was associated with less nausea and somnolence and an earlier return of bowel function after ambulatory surgery (56). Furthermore, it was recently reported that the administration of ketorolac (30 mg) at the incision site to supplement local anesthesia resulted in significantly less postoperative pain, a better quality of recovery, and earlier discharge compared with local anesthesia alone (57). However, when ketorolac was substituted for or combined with fentanyl during outpatient gynecologic and laparoscopic surgical procedures, the beneficial effects of the NSAID were more variable (58–60). Use of shock-wave lithotripsy to evaluate the effect of NSAIDs on visceral pain, diclofenac produced only a marginal opioid-sparing effect (61). Furthermore, when diclofenac (1 mg/kg IV) was administered before outpatient arthroscopic surgery, it was found to be associated with similar visual analog pain scores to fentanyl (1 μg/kg IV) (62). After gynecologic laparoscopy surgery (63), diclofenac decreased pain and analgesic requirements for 24 h postoperatively but had little effect on the recovery profile. Similarly, the administration of ketorolac during the perioperative period in outpatients undergoing laparoscopic cholecystectomy procedures (59) decreased postoperative opioid requirements, but this contributed to only a marginal improvement in ventilatory function at 4 hr after the operation. When diclofenac was administered preoperatively to pediatric patients, both the incidence of restlessness and crying and the postoperative opioid requirements were lower in the diclofenac-treated (versus acetaminophen-treated) patients (64). Oral ketorolac (1 mg/kg) compared favorably to small-dose acetaminophen (10 mg/kg) for bilateral myringotomy procedures in children, with the ketorolac-treated patients recording lower pain scores and requiring less analgesic medication in the early postoperative period (65). In children undergoing inguinal hernia repair (66), ketorolac (1 mg/kg IV) compared favorably to caudal bupivacaine 0.2% with respect to pain control and postoperative side effects. In fact, the ketorolac-treated patients had an improved recovery profile, including less vomiting, shorter times to voiding and ambulation, and earlier discharge home. Furthermore, the intraoperative administration of ketorolac as an adjuvant to general anesthesia in pediatric patients provided postoperative analgesia comparable to morphine (67). As expected, the ketorolac-treated patients experienced less postoperative nausea and vomiting. When ketorolac or morphine are administered for pain control in pediatric patients, ketorolac-induced analgesia develops more slowly but is longer lasting compared with morphine (68). Oral or rectal administration of NSAIDs can also be highly effective in the prophylactic management of pain after ambulatory surgery. For example, when oral naproxen was administered before laparoscopic surgery, postoperative pain scores, opioid requirements, and time to discharge were significantly reduced (69). Furthermore, premedication with oral ibuprofen (800 mg) was associated with superior postoperative analgesia and less nausea compared with fentanyl (75 μg IV) (70). However, the more important role for oral NSAIDs is in the postdischarge period. In a recent outpatient study involving the use of a multimodal analgesic technique consisting of alfentanil, lidocaine, ketorolac, and paracetamol (71), oral ibuprofen (800 mg every 8 h) was equianalgesic to paracetamol 800 mg plus codeine 60 mg (every 8 h) when administered during the first 72 h after discharge, and it resulted in better global patient satisfaction and less constipation than the opioid-containing oral analgesic. To achieve the optimal benefit of using NSAIDs in the perioperative period, these compounds should be continued as prophylactic analgesics for preventive pain management in the postdischarge period (45). COX-2 Inhibitors In an effort to minimize the potential for operative-site bleeding complications, as well as and associated with the NSAIDs, the more COX-2 are being increasingly used as non-opioid adjuvants for pain during the perioperative period (Table Early studies the use of and for analgesia when administered for oral premedication mg seems to more effective and analgesia compared with mg after surgery suggest that mg is to acetaminophen when administered before outpatient surgery However, mg produced significantly more effective analgesia than acetaminophen and the pain relief was more in the postdischarge period with also facilitated the recovery by reducing postoperative pain and the quality of recovery from the and of of COX-2 a COX-2 mg has been as an to ketorolac and diclofenac is a with an and is similar both and to and postoperative administration of this COX-2 seems to significant opioid-sparing effects, and these studies suggest that it can improve the quality of recovery and patient satisfaction with postoperative pain management. However, further clinical studies are needed to the optimal role of COX-2 in ambulatory surgery. the analgesics, acetaminophen is one of the most yet it is in the ambulatory setting. When administered in an oral or rectal acetaminophen can be a very adjuvant during the perioperative period and favorably to the NSAIDs in children Although et al. reported minimal effects after a mg/kg of et al. found that a mg/kg was as effective as ketorolac mg/kg IV in reducing pain after tonsillectomy procedures and was associated with less postoperative bleeding than the More et al. demonstrated that the opioid-sparing effect of acetaminophen was The optimal for acetaminophen in children consists of a of mg/kg by a of mg/kg every 6–8 h during the early postoperative period IV of known as has been administered to adults as an to ketorolac in the perioperative period is a that is and by to acetaminophen known as Although the future role of this non-opioid parenteral analgesic during the perioperative period is yet to be rectal acetaminophen has been used as an adjuvant to NSAIDs and local anesthetics in outpatients as part of a multimodal is a unique anesthetic with properties which has been used for both the and of anesthesia and as an analgesic adjuvant during MAC As a result of its well known (Table ketamine into in the anesthesia in the early However, the use of small-dose ketamine mg/kg IV) techniques seems to be associated with a less incidence of adverse and with greater patient and Recent studies have described the use of ketamine in combination with for MAC and IV anesthesia The administration of ketamine μg in combination with μg can the produced by producing effects after surgery, and it may provide for an earlier recovery of function In a bolus of ketamine mg/kg during surgery has been reported to significant opioid-sparing effects after painful ambulatory surgery procedures However, the clinical of preemptive analgesic effects remains controversial of and Non-Opioid Techniques Nonpharmacologic techniques (e.g., nerve and can also be used as adjuvants in the treatment of both acute and pain in the ambulatory setting the side effects produced by both opioid and non-opioid analgesics (Table it is that approaches will a more role in the management of pain after ambulatory surgery in the studies suggest that a decrease in the postoperative opioid In addition to that reduces pain and the need for oral analgesics, et al. reported a more rapid recovery of joint after outpatient arthroscopic surgery. In the et al. found the effect of on the for opioid analgesic medication and the quality of postoperative pain studies suggest that the location, and of are all important factors the of Moreover, the clinical of techniques remains controversial because of the potential of and difficulty in the effect of the Other approaches that have also been as analgesic adjuvants in the perioperative period and However, additional well controlled clinical studies are needed to the benefits of these modalities on patient after ambulatory surgery. As more and painful surgical procedures (e.g., laparoscopic and as well as shoulder and knee and are performed on an outpatient or the use of multimodal perioperative analgesic non-opioid analgesic will an increasingly important role in the recovery and patient satisfaction (3). pain management is to the benefits of ambulatory surgery for both patients and care studies are needed to the beneficial effects of these newer approaches with respect to important recovery (e.g., of and return to Although factors other than pain be controlled to minimize postoperative and facilitate the recovery after ambulatory surgery, pain remains a major of all patients undergoing surgical procedures It is that the anesthetic technique can the analgesic in the early postoperative period. Although opioid analgesics will to an important role in the management of to pain after surgery, the use of analgesics will a greater role in the Although anesthesia may not yet be for major surgical procedures, it is becoming increasingly popular for procedures in the ambulatory or setting In addition to the local anesthetics, NSAIDs, and drugs as and have also been to be adjuvants during or after surgery Use of analgesic with of may provide or effects with respect to pain control and the recovery Finally, and less analgesic delivery systems are needed to provide for more cost-effective pain relief in the postdischarge period after ambulatory surgery. In anesthesia with minimal postoperative should be for the of outpatients undergoing ambulatory surgical procedures, with the use of multimodal analgesic techniques. The of the analgesic technique should be not only to lower the pain scores, but more to facilitate earlier mobilization and by reducing complications after discharge home. Recent evidence that can more prevent postoperative pain and improve the recovery after ambulatory surgery by using a combination of preemptive multimodal techniques involving both centrally and peripherally analgesic as well as