Jeffrey M. Richman

Does continuous peripheral nerve block provide superior pain control to opioids? A meta-analysis.

Although most randomized clinical trials conclude that the addition of continuous peripheral nerve blockade (CPNB) decreases postoperative pain and opioid-related side effects when compared with opioids, studies have included relatively small numbers of patients and the majority failed to show statistical significance during all time periods for reduced pain or side effects. We identified studies primarily by searching Ovid Medline (1966 – May 21, 2004) for terms related to postoperative analgesia with CPNB and opioids. Each article from the final search was reviewed and data were extracted from tables, text, or extrapolated from figures as needed. Nineteen articles, enrolling 603 patients, met all inclusion criteria. Inclusion criteria were a clearly defined anesthetic technique (combined general/regional anesthesia, general anesthesia alone, peripheral nerve block), randomized trial, adult patient population (≥18 yr old), CPNB (or analgesia) used postoperatively (intrapleural catheters were deemed not to be classified as a peripheral nerve catheter), and opioids administered for postoperative analgesia in groups not receiving peripheral nerve block. Perineural analgesia provided better postoperative analgesia compared with opioids (P < 0.001). This effect was seen for all time periods measured for both mean visual analog scale and maximum visual analog scale at 24 h (P < 0.001), 48 h (P < 0.001), and 72 h (mean visual analog scale only) (P < 0.001) postoperatively. Perineural catheters provided superior analgesia to opioids for all catheter locations and time periods (P < 0.05). Nausea/vomiting, sedation, and pruritus all occurred more commonly with opioid analgesia (P < 0.001). A reduction in opioid use was noted with perineural analgesia (P < 0.001). CPNB analgesia, regardless of catheter location, provided superior postoperative analgesia and fewer opioid-related side effects when compared with opioid analgesia.

Efficacy of postoperative patient-controlled and continuous infusion epidural analgesia versus intravenous patient-controlled analgesia with opioids: a meta-analysis.

The authors performed a meta-analysis and found that epidural analgesia overall provided superior postoperative analgesia compared with intravenous patient-controlled analgesia. For all types of surgery and pain assessments, all forms of epidural analgesia (both continuous epidural infusion and patient-controlled epidural analgesia) provided significantly superior postoperative analgesia compared with intravenous patient-controlled analgesia, with the exception of hydrophilic opioid–only epidural regimens. Continuous epidural infusion provided statistically significantly superior analgesia versus patient-controlled epidural analgesia for overall pain, pain at rest, and pain with activity; however, patients receiving continuous epidural infusion had a significantly higher incidence of nausea–vomiting and motor block but lower incidence of pruritus. In summary, almost without exception, epidural analgesia, regardless of analgesic agent, epidural regimen, and type and time of pain assessment, provided superior postoperative analgesia compared to intravenous patient-controlled analgesia.

A comparison of regional versus general anesthesia for ambulatory anesthesia: a meta-analysis of randomized controlled trials.

Both regional anesthesia and general anesthesia have been proposed to provide optimal ambulatory anesthesia. We searched MEDLINE and other databases for randomized controlled trials comparing regional anesthesia and general anesthesia in ambulatory surgery patients for meta-analysis. Only major conduction blocks were considered to be regional anesthesia. Regional anesthesia was further separated into central neuraxial block and peripheral nerve block. Fifteen (1003 patients) and 7 (359 patients) trials for central neuraxial block and peripheral nerve block were included in the meta-analysis. Both central neuraxial block and peripheral nerve block were associated with increased induction time, reduced pain scores, and decreased need for postanesthesia care unit analgesics. However, central neuraxial block was not associated with decreased postanesthesia care unit bypass or time or reduced nausea despite reduced analgesics, and it was associated with a 35-min increase in total ambulatory surgery unit time. In contrast, peripheral nerve block was associated with decreased postanesthesia care unit need and decreased nausea but, again, not with decreased ambulatory surgery unit time. This meta-analysis indicates potential advantages for regional anesthesia, such as decreased postanesthesia care unit use, nausea, and postoperative pain. Although these factors have been proposed to reduce ambulatory surgery unit stay, neither central neuraxial block nor peripheral nerve block were associated with reduced ambulatory surgery unit time. Other factors, such as unsuitable discharge criteria and limitations of meta-analysis, may explain this discrepancy.

Postoperative cognitive function as an outcome of regional anesthesia and analgesia

Background and Objectives: It has been suggested that intraoperative neuraxial (spinal, epidural) anesthesia may decrease postoperative cognitive dysfunction when compared with general anesthesia, but the issue remains controversial. We systematically reviewed the data from published studies to determine the effect of intraoperative neuraxial anesthesia versus general anesthesia on postoperative cognitive dysfunction and delirium. Methods: Studies were identified by searching the PubMed database of the National Library of Medicine (1966 to 2003) for terms related to cognitive dysfunction after surgery. Inclusion criteria were a comparison of intraoperative neuraxial anesthesia versus general anesthesia, and the outcome of postoperative cognitive dysfunction. A total of 196 abstracts were identified, and 24 articles were analyzed. Each article was reviewed, and data were extracted from tables or text or extrapolated from figures as needed. Results: Of the 24 trials obtained, 19 were randomized and 4 were observational (nonrandomized) trials (1 trial was a combination of randomized and observational data). The age of patients studied was typically greater than 60 years, and a wide range of neuropsychometric tests were used to evaluate cognitive function. The majority of trials (23/24 of all trials and 18/19 of randomized trials) did not demonstrate a benefit from neuraxial anesthesia in decreasing the incidence of postoperative cognitive dysfunction. Conclusions: The use of intraoperative neuraxial anesthesia does not appear to decrease the incidence of postoperative cognitive dysfunction when compared with general anesthesia. There are methodologic and study-design issues present in many studies, and further elucidation of the pathophysiology of postoperative cognitive dysfunction may provide a direction for future studies.

Bevel direction and postdural puncture headache: a meta-analysis.

Background:The effect of lumbar puncture needle bevel direction on the incidence of postdural puncture headache (PDPH) is somewhat controversial. We performed a meta-analysis of available trials to determine if bevel direction during lumbar puncture would influence the incidence of PDPH. Review Summary:Studies were identified primarily by searching the National Library of Medicines PubMed database (1966 to November 29, 2004) and abstracts from several national meetings (American Society of Anesthesiology, International Anesthesia Research Society, American Society of Regional Anesthesia, Society of Obstetric Anesthesia and Perinatology) for terms related to needle and bevel direction. Inclusion criteria were assessment of the incidence of PDPH after lumbar puncture with a cutting needle (eg, Quincke, Tuohy), comparison of a “parallel” (bevel oriented in a longitudinal or cephalad to caudad direction) to “perpendicular” (bevel oriented in a transverse direction) orientation during needle insertion, randomized trials, and trials primarily in adult populations. Data on study characteristics and incidence of PDPH were abstracted from qualified studies and subsequently analyzed. The search resulted in 52 abstracts from which the original articles were obtained and data abstracted, with ultimately a total of 5 articles meeting all inclusion criteria. Insertion of a non–pencil-point/cutting needle with the bevel oriented in a parallel/longitudinal fashion resulted in a significantly lower incidence of PDPH compared with that oriented in a perpendicular/transverse fashion (unadjusted rates of 10.9% versus 25.8%; odds ratio = 0.29 [95% CI = 0.17–0.50]). Conclusions:Our meta-analysis indicates that with use of a cutting needle, insertion in a parallel/longitudinal fashion may significantly reduce the incidence of PDPH, although the reasons for this decrease are unclear.

Efficacy of bicarbonate in decreasing pain on intradermal injection of local anesthetics: a meta-analysis.

Objective: Intradermal injection of local anesthetic often results in pain on injection due in part to the acidic pH of commercially prepared solutions, which are optimized to prolong shelf life. Although there are other possible explanations (eg, noxious properties of local anesthetics, pressure effect of infiltration), the etiology is most likely multifactorial. Although addition of bicarbonate to local anesthetics may decrease pain on intradermal injection, the extent of this analgesic effect is uncertain. We performed a meta-analysis of available trials investigating pain during intradermal injection of buffered local anesthetic preparations. Methods: We searched the National Library of Medicines PubMed database for all relevant articles published on the topic through November 2006. Inclusion criteria included double-blind, randomized controlled trials and use of a visual analog scale to measure pain on infiltration of local anesthetic buffered with sodium bicarbonate compared with that of unbuffered local anesthetic. Meta-analysis was performed using the Review Manager 4.2.7 (The Cochrane Collaboration, 2004). A random-effects model was used. Results: Our search resulted in 86 abstracts, of which 12 articles met all inclusion criteria. Overall, there were 609 observations for buffered local anesthetic and 615 for unbuffered local anesthetic. Use of buffered local anesthetic resulted in a statistically lower weighted mean difference in visual analog scale of −1.17 (95% confidence interval, −1.68 to −0.67) compared with unbuffered local anesthetic. Conclusions: Our systematic review suggests that the use of buffered local anesthetics seems to be associated with a statistical decrease in pain of infiltration when compared with unbuffered local anesthetic.

Survey of the utilization of regional and general anesthesia in a tertiary teaching hospital.

Background: Although the subspecialty of regional anesthesiology has become an important focus during residency training, there are many factors that might influence a residents experience in regional anesthesia (RA). There are few data examining the utilization of regional techniques in an anesthesiology residency program. We undertook a prospective observational study to determine the frequency and reasons for not choosing RA in cases for which it was considered an option. Methods: All scheduled operative procedures that were amenable to neuraxial or major peripheral regional anesthetic techniques were surveyed. Data recorded included the type of intraoperative anesthetic used, type of anesthesiology faculty performing the regional block (regional anesthesiologist vs general anesthesiologist), and reasons for not choosing RA when a regional anesthetic technique was feasible. Results: Of the 2301 surgical procedures amenable to a regional technique, 839 (36.5%) involved use of regional anesthetic, and 1462 (63.5%) involved only a general anesthetic. Of the subjects receiving RA, 32% were performed by general anesthesiology faculty, and 68% were performed by regional anesthesiology faculty. The most common type of regional anesthetic performed by the general anesthesiology faculty was neuraxial blockade (95.2%) (vs 52.5% by regional anesthesiology faculty). Of the cases not involving RA, the reasons were anesthesiology related (40%), surgeon related (34%), patient related (12%), and medical contraindication related (14%). Conclusions: Our prospective observational study suggests that anesthesiology-related reasons may be an important factor for not undertaking these techniques. Although we did not specifically examine the effect on resident education, our study does provide some evidence to support program directors and department chiefs to set up their regional rotations with faculty most likely to perform RA.