The evidenced based practice of anesthesia- the 3rd edition-
- 1. EVIDENCE-BASED PRACTICE OF ANESTHESIOLOGY THIRD EDITION--- CHAPTER 51-- IS REGIONAL ANESTHESIA APPROPRIATE FOR OUTPATIENT SURGERY? ELIZABETH A. ALLEY, MD • MICHAEL F. MULROY, MD BY DR. ALI SAAD
- 2. INTRODUCTION • With the developments of the last three decades, outpatient surgery now constitutes more than 60% of surgery performed in US. • It has initiated major revisions in the approach to anesthetic management and has been supported by the development of new drugs and techniques. • Outpatient anesthesia requires more rapid recovery and a faster return to full mental function than standard inpatient procedures.
- 3. • It also requires minimum nausea, vomiting, and postop. pain that might otherwise delay hospital discharge or precipitate unplanned overnight admission. • The emphasis on home discharge has also elevated the patient’s perception of “satisfactory” anesthesia, which now includes a greater emphasis on alertness, a sense of well- being, and adequate pain relief at home without disabling side effects. • Fortunately, new GA agents meet many of these requirements, especially rapid induction and emergence, which will
- 4. • LA for the performance of surgery is ideal. • Local anesthetics cause no loss of consciousness and provide excellent residual postoperative analgesia. • This combination makes local anesthetic agents attractive options for outpatient surgery, where rapid discharge with minimal nausea and sedation is important to health care providers and patients. • RA has been shown in some series to provide the same advan- tages, but meta-analysis of published series fails to show accelerated discharge despite better analgesia and nausea
- 5. • Neuro-axial (spinal and epidural) techniques have also been advocated because of their rapid onset of dense anesthesia, but they also do not improve discharge and, like peripheral nerve blocks, require additional time for performance. • Neuro-axial approaches also require resolution of the block before a patient can walk, and they obviously require an alternative method of postoperative analgesia.
- 6. • There is also the issue of the potential for post spinal headaches and, more recently, transient neurologic symptoms (TNS) after spinal anesthesia. • Thus, although there are several advantages to regional techniques, it is legitimate to question whether regional anesthetic techniques are appropriate in the outpatient setting.
- 7. OPTIONS
- 8. • Major options available in outpatient anesthesia are LA, GA and regional techniques. • For the sake of focus, this chapter will not include a discussion of LA techniques because these have universally been shown to be ideal techniques in outpatient anesthesia. • This includes the use of LA for retro-bulbar, peri-bulbar, or topical anesthesia for cataract surgery, which has been associated with a low risk of morbidity and with rapid discharge and high satisfaction in the elderly high-risk patient group undergoing this operation. • Local techniques are also excellent for other superficial surgeries, such as hernia repair, breast biopsy, and perianal
- 9. • GA is the most frequently used alternative, primarily because of the newer drugs available. • The introduction of rapid-induction and fast-emergence general anesthetic agents (i.e., sevoflurane, Desflurane, and propofol) in the last 30 years has produced dramatic improvement in the early emergence from GA. • These advantages are balanced by side effects. • The absence of analgesia in the postoperative period necessitates the addition of opioids and their attendant mental
- 10. • The inhalational agents themselves continue to be associated with a 20% to 50% risk of postoperative nausea and vomiting, although this can be minimized by generous use of prophylactic medication. • Propofol appears to be associated with a lower frequency of this complication but requires greater resources to administer and is no less expensive than the volatile drugs. • The regional techniques offer a third alternative, also with
- 11. • The two major categories are peripheral nerve blockade (PNB) and neuraxial blockade (NAB). • Continuous peripheral nerve catheters (CPNB) have emerged as a third application. • There are multiple reports of PNB, including intravenous regional anesthesia of the upper and lower extremities, as well as specific nerve blocks of the brachial and lumbar plexus (summarized in the recent meta- analysis). • They require a somewhat longer time to perform and a longer time for
- 12. • NAB includes the use of spinal as well as epidural and caudal injection. • Caudal anesthesia is primarily limited to pediatric practice, where it is usually performed as an adjunct to a general anesthetic in this patient population. • SA should be the most effective example of regional techniques in the outpatient setting because of its simplicity of performance and rapidity of onset but may be limited by
- 13. EVIDENCE
- 14. • Most of the reports of regional techniques for outpatients are from enthusiastic supporters and usually do not include a comparative GA group. • These reports are positive in their descriptions of analgesia, discharge times, and patient satisfaction. • Although randomized blinded comparative studies are more desirable, it is impossible to perform a “blinded” study comparing the two because even the most naive of observers would be able to distinguish the presence of LA block from GA. • It is also difficult to successfully randomly assign patients to
- 15. • Nevertheless, the literature search and meta-analysis already mentioned reviewed 15 studies comparing GA with NAB (Table 51-1) and seven comparing PNB with general anesthesia (Table 51-2). • These studies support the use of RA when compared with GA in terms of superior analgesia and reduced nausea but raise concerns about the time involved and the impact on significant outcomes such as discharge time (Table 51-3).
- 17. • Seven studies of NAB and six trials of PNC that measured induction time showed an increase by 8 to 9 minutes in induction time associated with regional techniques. • Two of the studies showed that blocks performed in an induction room outside the operating room during the room turnover process could allow for the total anesthesia time to be competitive with GA. • Two other studies looking at the use of block rooms showed actual reductions in induction time. • The use of rapid-acting drugs, such as 2-chloroprocaine, and the presence of experienced anesthesiologists also appear to reduce the additional time required for regional techniques.
- 18. • Nevertheless, the overall data indicate that a greater time is required for the performance of blocks and the onset of satisfactory analgesia. • Ten studies of NAB showed no decrease in post anesthesia care unit (PACU) time, or in the rate of PACU bypass, probably related to the persistent immobility associated with neuraxial anesthesia in the early recovery phase. In contrast, PNB allowed for earlier discharge from phase 1 PACU, as well as a higher percentage of eligibility to bypass phase 1 at the end
- 19. • Both NAB and PNB were associated with significantly lower visual analog scale (VAS) scores in the PACU, as well as a significantly reduced requirement for postoperative analgesics in the PACU. • Despite better pain relief, as noted previously, no difference was seen in the PACU time with NAB. • A 40% reduction in nausea was associated with NAB, but this was not statistically different from the general anesthesia group. • PNB did provide a significant fivefold decrease in nausea.
- 20. •NAB actually required a longer discharge time than GA in 14 trials that reported discharge times, with an average prolongation of 35 minutes. •Although part of this prolonged discharge may have been related to the use of a longer acting spinal anesthetic (bupivacaine was used in six trials, although in low doses), additional requirements frequently associated with NAB in an ASU (for ambulation and voiding) may have contributed to the longer times. •Only one study used procaine, and none used 2- chloroprocaine, which has been reported to be associated
- 21. • In those studies that report results, success rates of 90% to 95% appear to be common, especially with PNBs. • SA and EA have a high reliability, but none of the techniques equals the 100% efficacy of GA. • All the comparisons of pharmaco-economics show that regional techniques are at least no more expensive than GA. • Satisfaction with central NAB was high (81%) but not significantly different from GA. • With PNB, there was a significant increase in patient satisfac- tion compared with GA (88% versus 72%).
- 23. ** Induction Rooms:-- • In a recent small study of efficiency and regional anesthesia, the authors noted that the use of an anesthesia care team, an induction room, and a “swing operating room” (two operating rooms for one team) decreased turnover time, increased the number of cases one surgeon could perform in a day and decreased overall hospital time compared with one anesthesiologist performing GA for day surgery hand cases. • Although this model used an induction room and two operating rooms, thus increasing the need for additional space, the authors reported a greater than $400 savings per patient due to decreased PACU stay alone.
- 24. **PERIPHERAL NERVE INFUSIONS:-- • The latest development in the application of regional techniques in the outpatient setting has been the use of continuous local anesthetic infusions through peripheral nerve catheters in patients who are discharged home from an outpatient unit. • The development of new catheter systems and especially new lightweight reliable portable infusion pumps has been instrumental in this change. • The use of these new technologies does not fit into the same paradigm as the previously discussed comparison of regional techniques with general anesthesia for the performance of
- 25. • This new technology may reframe the question of RA for out- patients: rather than an exclusive choice of GA or RA, growing data suggest that a combination of either RA or GA for the surgery with a CNPB for postoperative analgesia may be the optimal “package” for attaining the goals of ambulatory surgery. • In a review of 11 published studies of the use of continuous catheters, Ilfeld and Enneking found significant improvement in pain control after discharge in the patients who were treated with local anesthetic infusions compared with placebo in four trials. • In all the published series, there was a decreased use of oral analgesic medications when peripheral nerve catheters were
- 26. • This was associated with a reduction in several adverse side effects such as nausea and sleep disturbance with faster return to normal activity and greater patient satisfaction. • Specific examples include continuous interscalene blocks to decrease the time to discharge after total shoulder arthroplasty, continuous infraclavicular nerve block to benefit patients with elbow surgery and continuous femoral nerve blocks to decrease the time to discharge for patients after anterior cruciate ligament repairs. • Few of these series have measured the extent of additional time that is required for the placement of the catheters, which would be expected to exceed the performance of a simple single-injection PNB.
- 27. • The use of continuous catheters has also prompted attempts to be even more aggressive in performing procedures that previously required a hospital stay, such as joint replacement, on an outpatient basis. • Ilfeld and colleagues have reported preliminary experiences with CPNB therapy for elbow, hip and knee replacement that suggest that these procedures can be performed on an ambulatory basis (or, at most, with an overnight stay) because of the superior analgesia provided by CPNB. • Further research is needed to support these advanced applications of outpatient procedures.
- 29. • The major discussion appears to be about the perception of an increased time to perform regional techniques and the lower level of reliability of regional anesthesia, which counterbalance the higher degree of alertness, the potential for more rapid discharge, and the improved postoperative analgesia both in the PACU and after discharge home. • Thus the controversy is not necessarily whether regional anesthesia is appropriate in the outpatient setting but whether it is a cost-effective, reasonable alternative in a specific clinical setting. • In addition to that global controversy, more specific controversies appear to be related to the use of spinal
- 30. • The issue of post-spinal headaches remains a reality, although the use of new needles has appeared to reduce the incidence to less than 1% in adult outpatients. • Another controversy associated with subarachnoid anesthesia is the phenomenon of TNS that has been associated most particularly with the use of lidocaine. • This is unfortunate because lidocaine historically is the drug associated with the most rapid resolution of blockade and readiness for discharge. • Reduction of the dose or concentration does not appear to alleviate the frequency of the syndrome.
- 31. • Preliminary data suggest that the preservative-free 2- chloroprocaine may be a competitive alternative, but further data are needed on the safety and reduced incidence of TNS with this drug. • A recent retrospective review of one institution’s results with more than 4000 2-chloroprocaine spinal anesthetic procedures revealed no complications and a shorter discharge time than with lidocaine for the same procedure. • This retrospective review reported no instances of TNS with 2- chloroprocaine spinal anesthetics in the 503 patients reviewed. • In the meantime, it appears that patients undergoing arthroscopy or lithotomy-position operations on an outpatient
- 32. • However, SA is the most reliable and rapid in onset of the regional anesthetic techniques, and it should be the ideal technique for other uses in the outpatient setting. • Previous data had shown a high incidence of urinary retention with long-acting spinal blocks, but recent data suggest that urinary retention after a short-acting spinal anesthetic in low- risk patients (those with no history of retention and not undergoing hernia or urologic surgery) is not any more
- 33. GUIDELINES There are no formal guidelines on the use of RA in outpatient setting. Some general guidelines are based on the literature. Certain adjustments must be made to the techniques and the drugs to ensure an appropriate result.
- 34. • Excessive sedation for the performance of blocks must be avoided if the advantage of a high degree of alertness and rapid discharge is to be maintained. • Rapid onset and highly reliable techniques will help resolve some of the issues of efficiency and cost-effectiveness. • SA and IV RA are perhaps the most appropriate, given these considerations. • Ultrasound guidance may prove useful in shortening performance time of PNB and CPNB, but further data are
- 35. • PNBs appear to provide the greatest advantages in the outpatient setting in terms of discharge times, postoperative analgesia, PACU bypass, and reduction of nausea but are also associated with a slower onset than general anesthesia. • The performance of these blocks in a separate induction area is therefore optimal. • The choice of drugs for PNBs has not been addressed by any of the comparative studies, but it remains an issue. • Long-acting aminoamides may provide 12 to 24 hours of postoperative analgesia; CPNB has been used for as long as 72 hours.
- 36. • The benefits of these techniques must be weighed against the risk of injury to a numb extremity after discharge, and thus appropriate guidelines should include clear written instructions for all pts regarding the protection of extremities that remain anesthetized after discharge. • The use of continuous peripheral nerve infusions is associated with significant improvement in postop. analgesia, reduction of post discharge complications, and pt satisfaction. • The additional time required may well be offset by the advantages for more painful outpatient procedures. • SA is best performed with small-gauge, rounded bevel needles- -less incidence of PDPH– so should be limited to pts who can
- 37. • The problem of TNS has not yet been resolved. It appears to be lowest with the use of bupivacaine, although prolonged discharge may be associated with the use of this drug. • Discharge times after spinal anesthesia also require careful selection of drug and dose. • It appears that the addition of epinephrine to subarachnoid local anesthetics increases the potential for urinary retention and for prolonged discharge times. • The use of fentanyl may be a better choice for intensifying local anesthetic effect without prolonging discharge due to urinary retention.
- 38. • Urinary retention after a short-acting spinal anesthetic in low- risk patients is not any more frequent than with general anesthesia, and these patients can be discharged without mandatory voiding. • The duration of SA is proportional to the total milligram dose of the local anesthetic involved, and thus high-dose techniques are generally best avoided. • Data suggest that preservative-free 2-chloroprocaine provides the shortest duration, potentially competitive with GA. • Epidural anesthesia appears to be appropriate in the outpatient setting, although it should be limited to the use of short-acting drugs such as chloroprocaine and lidocaine.
- 39. AUTHORS’ RECOMMENDATIONS **On the basis of the data, we believe that regional anesthesia does have an appropriate role in outpatient setting if appropriate techniques, drugs, and doses are selected.
- 40. • LA is clearly ideal and should be used whenever possible as the sole anesthetic regimen or at least should be included for postoperative analgesia after any technique. • PNB is highly effective in providing postoperative analgesia and rapid discharge and should be used whenever possible for upper or lower extremity and truncal (hernia) surgical procedures. • Performance of a block in a separate induction room may reduce the additional time otherwise required for RA. • Additionally, the use of an anesthetic team—with the anesthesiologist performing RA and an anesthesia care team member in OT for monitoring during surgery—will decrease
- 41. • The use of CPNB provides maximum benefit, whether combined with GA or RA for the surgery itself. • The additional time required for the block is counterbalanced by the impressively superior postoperative analgesia over the next several days and the potential for more rapid discharge. • The reduced opioid use, nausea, and sleep disturbance contribute to significant patient satisfaction. • If NAB is chosen, SA has the advantages of rapid onset and high reliability. • Unfortunately, there is still a persistent risk of transient neurologic symptoms (TNS) with the drugs and doses that are
- 42. • A low dose of bupivacaine (less than 6 mg) will provide a low risk of TNS with the potential for a short discharge time; however, a high degree of variability exists and surgical anesthesia to the lower extremity and rectal area may be limited. • The use of 2-chloroprocaine may provide a low risk of TNS with an even more reliable and desirable shorter discharge time, but this has yet to be proved. • An epidural anesthetic procedure provides a more rapid discharge than with most of the current spinal techniques and has the added advantage of flexibility in duration and extent of