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Director of Regional Anesthesia, St. Luke’s-Roosevelt Hospital Center, Associate Professor of Anesthesia, College of Physicians and Surgeons, Columbia University, New York, New York
Address correspondence and reprint requests to Admir Hadzic, MD, Director of Regional Anesthesia, St. Luke’s-Roosevelt Hospital Center, Associate Professor of Anesthesia, College of Physicians and Surgeons, Columbia University, New York, NY, 1111 Amsterdam Avenue, New York, NY 10025. Address e-mail to admir{at}nysora.com.
In the current issue of Anesthesia & Analgesia, Liu et al. (1) report the findings of their meta-analysis examining whether peripheral nerve blocks (PNBs), centroneuraxial blocks (CNBs), or general anesthesia (GA) provide superior anesthesia for ambulatory surgery. To derive their conclusions, the authors used a meta-analysis and grouped together a variety of surgical procedures, regional anesthesia techniques, and choices of local anesthetics. The primary purpose of this editorial is not to discuss the well known limitations of the meta-analysis (particularly in the setting of heterogenous data); other authors have done a good job of clarifying these issues (2). This editorial aims at offering a wider angle view on the traditional regional versus general anesthesia debate.
To accomplish fast-tracking, GA must be coupled with state-of-the-art "multimodal" anesthetic techniques consisting of nonsteroidal antiinflammatory drugs, local anesthetic wound infiltration, routine antiemetic prophylaxis, rapid emergence anesthetics, and cerebral monitoring to more accurately titrate the dosages of these anesthetics (3,4). Significant research has been performed to determine whether newer shorter-acting anesthetics (e.g., desflurane, sevoflurane, propofol, and remifentanil) can enhance our ability to fast track (4,6). However, despite the faster early recovery profile of these "high-tech" GA techniques, actual cost savings have been difficult to establish. In fact, the current impetus to discharge patients quickly may not result in tangible financial savings or even interest practitioners outside of the United States (5). One might even argue that we are already at a plateau with regard to our ability to improve already excellent recovery, safety profile, and fast tracking or to realize further cost reduction with GA.
Similarly, a significant amount of research has been done regarding use of CNBs in outpatients. Despite an excellent immediate recovery profile (1), the main problems with CNBs are patient inability to ambulate during the block’s duration and the need to establish an alternate analgesic regimen when the short-acting CNB wears off. For these reasons, Liu et al.’s finding that CNBs are associated with discharge delays is hardly surprising (1). In fact, it is this limitation (and the reports of neurotoxicity of intrathecally injected local anesthetics) that has renewed interest in using ultrashort-acting local anesthetics (e.g., 2-chloroprocaine) to speed recovery and shorten time to discharge (6). Unfortunately, shortening the duration of the CNB is not without its drawbacks: ultrashort-acting local anesthetics can be used only in operations of very short duration. In addition, as one shortens the duration of the blockade, one also diminishes the postoperative analgesic benefit of the CNB.
Theoretically, by providing site-specific analgesia while allowing ambulation or assisted ambulation, PNBs should offer several advantages over CNBs or GA. Indeed, the data from the meta-analysis by Liu et al. support this theory (1). Use of PNBs provided significantly more comfortable recoveries by decreasing rates of nausea, vomiting, and severe postoperative pain compared with GA and resulted in shorter recovery room stays and improved patient satisfaction in the ambulatory settings. In addition, as a result of their potent analgesic properties, PNBs have been shown to prevent hospital admission, particularly when used in patients undergoing more painful surgeries (7,8). The finding by Liu et al. that PNBs did not shorten the time to discharge is hardly surprising given the lack of clear discharge guidelines that would capitalize on the advantages of PNBs. As an example, nearly half of the respondents of a physician survey reported that they did not routinely discharge patients home with a long-lasting nerve block (9).
Perhaps the findings of Liu et al. can be characterized as "old-news-new-news." Few would argue that PNBs do not offer a clear advantage for specific outpatient surgical indications (e.g., painful orthopedic procedures). However, the more important question is whether these results are reproducible in institutions without a tradition of using PNBs and by practitioners without experience in PNBs equivalent to those of the authors. As opposed to an injection of a drug into a free-flowing IV, the success of a regional anesthetic, particularly a PNB, is very much operator-dependent. For instance, recent studies on the use of interscalene nerve block for shoulder surgery yielded 2 completely differing results: in one study, interscalene brachial plexus block failed to provide anesthesia in 82% of the patients, (10) whereas other studies have reported 100% success rates for the same indication (7,11). PNBs are typically practiced by relatively few, highly skilled practitioners who have invested significant effort and dedicated a significant part of their professional lives to mastering PNB procedures (12). For that reason, the advantages of PNBs summarized by Liu et al. in their meta-analysis may not be reproducible by, or applicable to, a wider anesthesia community.
The lack of practice standards, clinical pathways, and standard documentation, as well as a virtual absence of monitoring to increase success rates and decrease the risk of complications, has not paralleled the advances in GA in the same areas (13). This is in part because modern PNBs have only been introduced to clinical practice during the last 15 yr or so. It is only a recent large body of work on functional regional anesthesia anatomy, refinement of PNB techniques, development of newer equipment, nerve stimulators, and, more recently, imaging techniques, that have begun the transformation of this—perhaps both the youngest and the oldest—anesthesia subspecialty into a modern, more exacting clinical discipline.
In the quest for technical perfection, however, it is important to not lose sight of the main outcome variable of all regional anesthesia techniques: patient benefit rather than trivial variations in block procedures. Indeed, a quick scan of the literature reveals a plethora of publications on the effects of miniscule modifications of PNB techniques on block success rate and patient satisfaction. Ironically, glancing through these published reports, it looks as though success rates nearing 100% (7,11), have already been achieved. In contrast, few outcome studies have examined whether the currently used and effective PNBs actually make a meaningful difference in patient care. Consequently, Liu et al. had only 7 studies of sufficient quality for their meta-analysis of regional anesthesia versus GA.
In summary, the meta-analysis by Liu et al. in the current issue of Anesthesia & Analgesia is both timely and untimely. It is timely because the advent and rapid expansion of ambulatory surgery needs to be coupled with suitable anesthetic techniques to capitalize on the premise of ambulatory surgery: rapid recovery; avoidance of adverse effects such as nausea, vomiting, and drowsiness; a diminution of pain; and rapid discharge home. However, their analysis is also untimely because there are only a handful of studies focusing on the outcome difference between PNBs and other types of anesthesia. Therefore, one must ask how an analysis like this adds to the data already available in randomized clinical trials (2).
Future research must be directed at standardizing the practice of PNBs and regional anesthesia at large, objective documentation and injection procedure monitoring, and designing quality clinical outcome studies to help clinicians determine best-practice protocols in scenarios where regional anesthesia has been shown to make a clear difference when compared with other, more widely used anesthesia techniques. If the results of the future outcome studies are nearly as favorable as those summarized by Liu et al., perhaps the time has come to more clearly define a subspecialty track in ambulatory regional anesthesia and to assure the wider availability of this service, as well as its quality, safety, and reproducibility. This may be the only approach that will enable PNB techniques to be more universally appreciated and of greater benefit to both patients and health care providers.
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  P. F. White, H. Kehlet, J. M. Neal, T. Schricker, D. B. Carr, F. Carli, and the Fast-Track Surgery Study Group The Role of the Anesthesiologist in Fast-Track Surgery: From Multimodal Analgesia to Perioperative Medical Care Anesth. Analg., June 1, 2007; 104(6): 1380 - 1396. [Abstract] [Full Text] [PDF]
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K. J. Chamberlin General Versus Regional: Why Either/Or? Anesth. Analg., October 1, 2006; 103(4): 1058 - 1059. [Full Text] [PDF]
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P. F. White Choice of peripheral nerve block for inguinal herniorrhaphy: is better the enemy of good? Anesth. Analg., April 1, 2006; 102(4): 1073 - 1075. [Full Text] [PDF]
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