egional anesthesia and analgesia (RAA) is a major form of perioperative anesthesia and analgesia that has been shown to attenuate perioperative pathophysiology, provide superior postoperative analgesia and possibly improve patient outcomes. There is some controversy surrounding the efficacy of these techniques in improving patient outcomes, which may reflect methodologic shortcomings in the available data.

What Outcomes Should Be Measured?
Traditionally the most common outcomes assessed are mortality/major morbidity such as myocardial infarction. These “traditional” outcomes are the ones with which clinicians are most comfortable and familiar. Although not as familiar or assessed as frequently in the anesthesiology literature, “nontraditional” patient-oriented outcomes such as patient satisfaction, quality of life and quality of recovery also are valid outcomes and have become important endpoints in other areas of medicine, reflecting the general increased interest in patient-focused assessments (e.g., “customer service”). Patient-oriented outcomes will gain greater acceptance in anesthesiology, especially considering that advances in anesthesia care have decreased the incidence of mortality/major morbidity to the point where it may be difficult to measure these outcomes without large, randomized, controlled trials (RCT) or databases. Other outcomes include economic assessments of the impact of RAA.

Why Would RAA Be Associated With Improved Outcomes?
Peripheral and neuraxial RAA techniques, especially utilizing a local anesthetic-based solution, are associated with attenuation of perioperative pathophysiology (e.g., neuroendocrine stress response), the reduction of which may theoretically lead to preservation of patient physiology, particularly in patients with a decreased physiologic reserve and a decrease in adverse events such as deep venous thrombosis (DVT), pulmonary embolism (PE), pulmonary complications, myocardial infarction (MI) and even death.^1-4 In addition the use of RAA techniques results in superior postoperative analgesia⁵, which may allow patients to participate in postoperative physiotherapy (e.g., incentive spirometry) that may facilitate recovery.

Neuraxial Anesthesia-Analgesia and Patient Outcomes
The majority of the available literature has focused on the effect of neuraxial RAA on “traditional” patient outcomes. Some of the available systematic reviews and meta-analyses suggest that compared to general anesthesia followed by systemic opioids, neuraxial RAA may potentially decrease the incidence of hypercoagulable events (DVT, PE, graft failure), pulmonary complications, MI (for thoracic epidural only) and return of gastrointestinal function,^1-3 although there is some controversy regarding the validity of such data (see below).

Peripheral Anesthesia-Analgesia and Patient Outcomes
There has been an increase in popularity of peripheral RAA techniques, especially in the ambulatory surgical patient. Data examining the effect of peripheral RAA on patient outcomes are not as extensive as that for neuraxial RAA; however, systematic analysis of available data indicates that peripheral RAA techniques may improve some economic measures (decrease postanesthesia care unit [PACU] recovery room time, facilitate PACU bypass) and decrease postoperative pain and nausea in ambulatory surgical patients.⁶ Another systematic review indicates that peripheral RAA may lead to improvements in patient satisfaction.⁷

Why Don’t We Have a Definitive Answer Yet?
Despite the potential physiologic benefits of RAA in attenuating perioperative pathophysiology and superior analgesia conferred by RAA, the overall benefits of these techniques on patient outcomes are still debated. Some large RCTs show no benefits in decreasing mortality/overall morbidity whereas other data demonstrate a decrease in these outcomes with use of RAA.^1,3,4 The uncertainties in the benefits of RAA in decreasing mortality/major morbidity provide data for both advocates and detractors of RAA.

There are many reasons why we do not have a definitive answer as to whether RAA may improve patient outcomes, especially “traditional” endpoints. Each type of study design used to evaluate this issue has distinct weaknesses. Many large RCTs are underpowered to determine a rare outcome such as death. The relatively rigorous methodology of an RCT may limit the generalizability (external validity) of the results to a broader, typical clinical population.³ On the other hand, meta-analyses may be limited by the presence of data heterogeneity and biases.⁵ Finally, database analyses may be limited by missing data and lack of causality that an RCT offers.⁸

Other reasons why a definitive answer is lacking is that the RAA technique, per se, cannot be considered as a single generic intervention. The effect of RAA, particularly that placed neuraxially, will be influenced by the analgesic regimen used (local anesthetic versus opioid), congruency of catheter placement to incisional site, duration of analgesia and the incorporation of RAA into a multimodal approach.³ Thus placement of an RAA technique by itself does not automatically confer an improvement in patient outcomes, but the actual management tailored to the individual patient’s needs may improve outcomes.

Future Directions
Additional data are needed to elucidate the effect of RAA on patient outcomes; however, the emphasis may be different from traditional approaches, especially considering the extremely low rates of mortality/major morbidity and increasing importance of patient-oriented (nontraditional) outcomes. Since different analgesic modalities (epidural analgesia versus intravenous patient-controlled analgesia) provide different levels of analgesia with different side effects, future studies might consider examining the effect of different analgesic modalities on patient-oriented outcomes (satisfaction, quality of recovery) as a primary endpoint. Certainly this may require creation of new validated survey instruments.

Although much of the available literature for neuraxial RAA has focused on certain major morbidity (cardiac/pulmonary endpoints), the effect of RAA (both peripheral and neuraxial) on other major morbidity (cognitive function) has not been examined. Additional data are required to determine the effect of peripheral RAA on both traditional and nontraditional outcomes. Few data are available on the economic impact or cost-effectiveness of both peripheral and neuraxial RAA.

Finally, the superior analgesia provided by RAA may ultimately contribute to improvements in long-term outcomes such as functional recovery and a decrease in the incidence of chronic pain.^9,10

Summary
Available data suggest that RAA will attenuate perioperative pathophysiology, which may lead to an improvement in “traditional” patient outcomes. In addition RAA may provide superior postoperative analgesia that may contribute to an improvement in nontraditional patient-oriented outcomes. It is important to realize, however, that the benefits of an RAA technique are optimized when customized to the individual patient’s requirements. Future studies may reveal additional benefits of both peripheral and neuraxial RAA on important long-term endpoints.


References:

1. Rodgers A, Walker N, Schug S, et al. Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: Results from overview of randomized trials. Br Med J. 2000; 321:1493.

2. Liu S, Carpenter RL, Neal JM. Epidural anesthesia and analgesia. Their role in postoperative outcome. Anesthesiology. 1995; 82:1474-1506.

3. Wu CL, Fleisher LA. Outcomes research in regional anesthesia and analgesia. Anesth Analg. 2000; 91:1232-1242.

4. Rigg JR, Jamrozik K, Myles PS, et al. MASTER Anaesthesia Trial Study Group. Epidural anaesthesia and analgesia and outcome of major surgery: A randomised trial. Lancet. 2002; 359:1276-1282.

5. Block BM, Liu SS, Rowlingson AJ, et al. Efficacy of postoperative epidural analgesia versus systemic opioids: A meta-analysis. JAMA. 2003; 290:2455-2463.

6. Liu SS, Strodtbeck WM, Richman JM, et al. Comparison of regional versus general anesthesia for ambulatory anesthesia: A meta-analysis of randomized controlled trials. 79th IARS Clinical & Scientific Congress. Honolulu, Hawaii. March 2005.

7. Wu CL, Naqibuddin M, Fleisher LA. Measurement of patient satisfaction as an outcome of regional anesthesia and analgesia. Reg Anesth Pain Med. 2001; 26:196-208.

8. Wu CL, Hurley RW, Anderson GF, et al. The effect of perioperative epidural analgesia on patient mortality and morbidity in the Medicare population. Reg Anesth Pain Med. 2004; 29:525-533.

9. Gottschalk A, Smith DS, Jobes DR, et al. Pre-emptive epidural analgesia and recovery from radical prostatectomy: A randomized controlled trial. JAMA. 1998; 279:1076-1082.

10. Perkins FM, Kehlet H. Chronic pain as an outcome of surgery. A review of predictive factors. Anesthesiology. 2000; 93:1123-1133.

Financial support: Supported by the Department of Anesthesiology and Critical Care Medicine of Johns Hopkins University, Baltimore, Maryland.