Regional Anesthesia for Vascular Surgery and Pain Management.

Patients undergoing vascular surgery tend to have significant systemic comorbidities. Vascular surgery itself is also associated with greater cardiac morbidity and overall mortality than other types of noncardiac surgery. Regional anesthesia is amenable as the primary anesthetic technique for vascular surgery or as an adjunct to general anesthesia. When used as the primary anesthetic, regional anesthesia techniques avoid complications associated with general anesthesia in this challenging patient population. In this article, the authors describe regional anesthetic techniques for carotid endarterectomy, arteriovenous fistula creation, lower extremity bypass surgery, and amputation.

Liposomal Bupivacaine Plus Bupivacaine Versus Ropivacaine Plus Dexamethasone Brachial Plexus Blockade for Arthroscopic Rotator Cuff Repair: An Unblinded Randomized Controlled Trial.

Brachial plexus blockade is utilized for pain control during arthroscopic rotator cuff repair. The purpose of the present study was to evaluate brachial plexus blockade with liposomal bupivacaine plus bupivacaine (LB+B) as compared with ropivacaine plus dexamethasone (R+D) for arthroscopic rotator cuff repair. Our hypothesis was that the use of LB+B would result in lower pain scores and opioid consumption as compared with R+D. Methods: We performed a randomized controlled trial of 45 patients receiving ultrasound-guided brachial plexus blockade with LB+B and 44 patients receiving R+D prior to arthroscopic rotator cuff repair. The "worst pain" score in a 24-hour period, oral morphine equivalent dose (OMED), and overall benefit of analgesia score (OBAS) were recorded for 8 days following surgery. Results: Patient-reported "worst pain" was significantly lower in the LB+B group as compared with the R+D group on postoperative day 0 through day 5. OMED was significantly less for all 8 days studied, with an average cumulative 8-day OMED of 48.5 milligram equivalents in the LB+B group as compared with 190.1 milligram equivalents in the R+D group (p < 0.001). The OBAS score was significantly lower in the LB+B group as compared with R+D group on all postoperative days. The use of LB+B for brachial plexus blockade resulted in a 4% complication rate in a population of patients predominantly with American Society of Anesthesiologists (ASA) scores of 1 and 2. Conclusions: The use of LB+B for brachial plexus blockade during arthroscopic rotator cuff repair was associated with a significant and sustained decrease in the "worst pain" score, opioid consumption, and OBAS compared with R+D. LB+B for brachial plexus blockade also exhibited a strong safety profile. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Regional analgesia for cardiac surgery.

PURPOSE OF REVIEW: Regional anesthesia is gaining attention as a valuable component of multimodal, opioid-sparing analgesia in cardiac surgery, where improving the patient's quality of recovery while minimizing the harms of opioid administration are key points of emphasis in perioperative care. This review serves as an outline of recent advancements in a variety of applications of regional analgesia for cardiac surgery. RECENT FINDINGS: Growing interest in regional analgesia, particularly the use of newer "chest wall blocks", has led to accumulating evidence for the efficacy of multiple regional techniques in cardiac surgery. These include a variety of technical approaches, with results consistently demonstrating optimized pain control and reduced opioid requirements. Regional and pain management experts have worked to derive consensus around nerve block nomenclature, which will be foundational to establish best practice, design and report future research consistently, improve medical education, and generally advance our knowledge in this vital area of perioperative patient care. SUMMARY: The field of regional analgesia for cardiac surgery has matured over the last several years. A variety of regional techniques have been described and shown to be efficacious as part of the multimodal, opioid-sparing approach to pain management in the cardiac surgical setting.

The Effect of the No Pain Labor & Delivery-Global Health Initiative on Cesarean Delivery and Neonatal Outcomes in China: An Interrupted Time-Series Analysis.

BACKGROUND: The proportion of live births by cesarean delivery (CD) in China is significant, with some, particularly rural, provinces reporting up to 62.5%. The No Pain Labor & Delivery-Global Health Initiative (NPLD-GHI) was established to improve obstetric and neonatal outcomes in China, including through a reduction of CD through educational efforts. The purpose of this study was to determine whether a reduction in CD at a rural Chinese hospital occurred after NPLD-GHI. We hypothesized that a reduction in CD trend would be observed. METHODS: The NPLD-GHI program visited the Weixian Renmin Hospital, Hebei Province, China, from June 15 to 21, 2014. The educational intervention included problem-based learning, bedside teaching, simulation drill training, and multidisciplinary debriefings. An interrupted time-series analysis using segmented logistic regression models was performed on data collected between June 1, 2013 and May 31, 2015 to assess whether the level and/or trend over time in the proportion of CD births would decline after the program intervention. The primary outcome was monthly proportion of CD births. Secondary outcomes included neonatal intensive care unit (NICU) admissions and extended NICU length of stay, neonatal antibiotic and intubation use, and labor epidural analgesia use. RESULTS: Following NPLD-GHI, there was a level decrease in CD with an estimated odds ratio (95% confidence interval [CI]) of 0.87 (0.78-0.98), P = .017, with odds (95% CI) of monthly CD reduction an estimated 3% (1-5; P < .001), more in the post- versus preintervention periods. For labor epidural analgesia, there was a level increase (estimated odds ratio [95% CI] of 1.76 [1.48-2.09]; P < .001) and a slope decrease (estimated odds ratio [95% CI] of 0.94 [0.92-0.97]; P < .001). NICU admissions did not have a level change (estimated odds ratio [95% CI] of 0.99 [0.87-1.12]; P = .835), but the odds (95% CI) of monthly reduction in NICU admission was estimated 9% (7-11; P < .001), greater in post- versus preintervention. Neonatal intubation level and slope changes were not statistically significant. For neonatal antibiotic administration, while the level change was not statistically significant, there was a decrease in the slope with an odds (95% CI) of monthly reduction estimated 6% (3-9; P < .001), greater post- versus preintervention. CONCLUSIONS: In a large, rural Chinese hospital, live births by CD were lower following NPLD-GHI and associated with increased use of labor epidural analgesia. We also found decreasing NICU admissions. International-based educational programs can significantly alter practices associated with maternal and neonatal outcomes.

Depth of sedation as an interventional target to reduce postoperative delirium: mortality and functional outcomes of the Strategy to Reduce the Incidence of Postoperative Delirium in Elderly Patients randomised clinical trial.

BACKGROUND: The Strategy to Reduce the Incidence of Postoperative Delirium in the Elderly trial tested the hypothesis that limiting sedation during spinal anaesthesia decreases in-hospital postoperative delirium after hip fracture repair. This manuscript reports the secondary outcomes of this trial, including mortality and function. METHODS: Two hundred patients (≥65 yr) undergoing hip fracture repair with spinal anaesthesia were randomised to heavier [modified Observer's Assessment of Alertness/Sedation score (OAA/S) 0-2] or lighter (OAA/S 3-5) sedation, and were assessed for postoperative delirium. Secondary outcomes included mortality and return to pre-fracture ambulation level at 1 yr. Kaplan-Meier analysis, multivariable Cox proportional hazard model, and logistic regression were used to evaluate intervention effects on mortality and odds of ambulation return. RESULTS: One-year mortality was 14% in both groups (log rank P=0.96). Independent risk factors for 1-yr mortality included: Charlson comorbidity index [hazard ratio (HR)=1.23, 95% confidence interval (CI), 1.02-1.49; P=0.03], instrumental activities of daily living [HR=0.74, 95% CI, 0.60-0.91; P=0.005], BMI [HR=0.91, 95% CI 0.84-0.998; P=0.04], and delirium severity [HR=1.20, 95% CI, 1.03-1.41; P=0.02]. Ambulation returned to pre-fracture levels, worsened, or was not obtained in 64%, 30%, and 6% of 1 yr survivors, respectively. Lighter sedation did not improve odds of ambulation return at 1 yr [odds ratio (OR)=0.76, 95% CI, 0.24-2.4; P=0.63]. Independent risk factors for ambulation return included Charlson comorbidity index [OR=0.71, 95% CI, 0.53-0.97; P=0.03] and delirium [OR=0.32, 95% CI, 0.10-0.97; P=0.04]. CONCLUSIONS: This study found that in elderly patients having hip fracture surgery with spinal anaesthesia supplemented with propofol sedation, heavier intraoperative sedation was not associated with significant differences in mortality or return to pre-fracture ambulation up to 1 yr after surgery. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT00590707.

Effect of Depth of Sedation in Older Patients Undergoing Hip Fracture Repair on Postoperative Delirium: The STRIDE Randomized Clinical Trial.

Importance: Postoperative delirium is the most common complication following major surgery in older patients. Intraoperative sedation levels are a possible modifiable risk factor for postoperative delirium. Objective: To determine whether limiting sedation levels during spinal anesthesia reduces incident delirium overall. Design, Setting, and Participants: This double-blind randomized clinical trial (A Strategy to Reduce the Incidence of Postoperative Delirum in Elderly Patients [STRIDE]) was conducted from November 18, 2011, to May 19, 2016, at a single academic medical center and included a consecutive sample of older patients (≥65 years) who were undergoing nonelective hip fracture repair with spinal anesthesia and propofol sedation. Patients were excluded for preoperative delirium or severe dementia. Of 538 hip fractures screened, 225 patients (41.8%) were eligible, 10 (1.9%) declined participation, 15 (2.8%) became ineligible between the time of consent and surgery, and 200 (37.2%) were randomized. The follow-up included postoperative days 1 to 5 or until hospital discharge. Interventions: Heavier (modified observer's assessment of sedation score of 0-2) or lighter (observer's assessment of sedation score of 3-5) propofol sedation levels intraoperatively. Main Outcomes and Measures: Delirium on postoperative days 1 to 5 or until hospital discharge determined via consensus panel using Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) criteria. The incidence of delirium was compared between intervention groups with and without stratification by the Charlson comorbidity index (CCI). Results: Of 200 participants, the mean (SD) age was 82 (8) years, 146 (73%) were women, 194 (97%) were white, and the mean (SD) CCI was 1.5 (1.8). One hundred participants each were randomized to receive lighter sedation levels or heavier sedation levels. A good separation of intraoperative sedation levels was confirmed by multiple indices. The overall incident delirium risk was 36.5% (n = 73) and 39% (n = 39) vs 34% (n = 34) in heavier and lighter sedation groups, respectively (P = .46). Intention-to-treat analyses indicated no statistically significant difference between groups in the risk of incident delirium (log-rank test χ2, 0.46; P = .46). However, in a prespecified subgroup analysis, when stratified by CCI, sedation levels did effect the delirium risk (P for interaction = .04); in low comorbid states (CCI = 0), heavier vs lighter sedation levels doubled the risk of delirium (hazard ratio, 2.3; 95% CI, 1.1- 4.9). The level of sedation did not affect delirium risk with a CCI of more than 0. Conclusions and Relevance: In the primary analysis, limiting the level of sedation provided no significant benefit in reducing incident delirium. However, in a prespecified subgroup analysis, lighter sedation levels benefitted reducing postoperative delirium for persons with a CCI of 0. Trial Registration: clinicaltrials.gov Identifier: NCT00590707.

Seldinger technique for nasal intubation: a case series.

Nasotracheal intubation can be both challenging and traumatic, especially in cases of atypical anatomy. We present a series of 3 such cases in which an endotracheal tube introducer (bougie) was used to facilitate successful, atraumatic, nasotracheal intubation via Seldinger technique. The technique described can guide a nasotracheal tube through narrow nasal passages, small pharyngeal spaces, and past acute laryngeal approach angles, all without transoral manipulation of the tube. The technique is easy to perform, uses a routine skill set, and can be advantageous in numerous clinical scenarios.

No Pain Labor & Delivery: A Global Health Initiative's Impact on Clinical Outcomes in China.

The availability of labor analgesia is highly variable in the People's Republic of China. There are widespread misconceptions, by both parturients and health care providers, that labor epidural analgesia is harmful to mother and baby. Meanwhile, China has one of the highest cesarean delivery rates in the world, exceeding 50%. The goal of the nongovernmental No Pain Labor & Delivery (NPLD) is to facilitate sustainable increases in vaginal delivery rates by increasing access to safe neuraxial labor analgesia, thereby decreasing the cesarean delivery rate. NPLD was launched in 2008 with the stated goal of improving labor outcome in China by increasing the absolute labor epidural analgesia rate by 10%. NPLD established 10 training centers over a 10-year period. We hypothesized that increased availability of labor analgesia would result in reduced requests for cesarean delivery and better labor outcomes for mother and baby. Multidisciplinary teams of Western clinicians and support staff traveled to China for 8 to 10 days once a year. The approach involved establishing 24/7 obstetric anesthesia coverage in Chinese hospitals through education and modeling multidisciplinary approaches, including problem-based learning discussions, bedside teaching, daily debriefings, simulation training drills, and weekend conferences. As of November 2015, NPLD has engaged with 31 hospitals. At 24 of these sites, 24/7 obstetric anesthesia coverage has been established and labor epidural analgesia rates have exceeded 50%. Lower rates of cesarean delivery, episiotomy, postpartum blood transfusion, and better neonatal outcomes were documented in 3 impact studies comprising approximately 55,000 deliveries. Changes in practice guidelines, medical policy, and billing codes have been implemented in conjunction with the modernization of perinatal practice that has occurred concurrently in China since the first NPLD trip in 2008.

The role of perioperative chewing gum on gastric fluid volume and gastric pH: a meta-analysis.

STUDY OBJECTIVE: To determine if preoperative gum chewing affects gastric pH and gastric fluid volume. DESIGN: Systematic review and meta-analysis. METHODS: Data sources included Cochrane, PubMed, and EMBASE databases from inception to June 2012 and reference lists of known relevant articles without language restriction. Randomized controlled trials in which a treatment group that chewed gum was compared to a control group that fasted were included. Relevant data, including main outcomes of gastric fluid volume and gastric pH, were extracted. RESULTS: Four studies involving 287 patients were included. The presence of chewing gum was associated with small but statically significant increases in gastric fluid volume (mean difference = 0.21 mL/kg; 95% confidence interval, 0.02-0.39; P = .03) but not in gastric pH (mean difference = 0.11 mL/kg; 95% confidence interval, -0.14 to 0.36; P = .38). Gastric fluid volume and gastric pH remained unchanged in subgroup analysis by either sugar or sugarless gum type. CONCLUSIONS: Chewing gum in the perioperative period causes small but statically significant increases in gastric fluid volume and no change in gastric pH. The increase in gastric fluid most likely is of no clinical significance in terms of aspiration risk for the patient. Elective surgery should not necessarily be canceled or delayed in healthy patients who accidentally chew gum preoperatively.

Evaluation of epidural and peripheral nerve catheter heating during magnetic resonance imaging.

BACKGROUND: Many epidural and peripheral nerve catheters contain conducting wire that could heat during magnetic resonance imaging (MRI), requiring removal for scanning. METHODS: We tested 2 each of 6 brands of regional analgesia catheters (from Arrow International [Reading, Pennsylvania], B. Braun Medical Inc [Bethlehem, Pennsylvania], and Smiths Medical/Portex [Keene, New Hampshire]) for exposure to clinical 1.5- and 3-T MRI. Catheters testing as nonmagnetic were placed in an epidural configuration in a standard human torso-sized phantom, and an MRI pulse sequence applied at the maximum scanner-allowed radiofrequency specific absorption rate (SAR) for 15 minutes. Temperature and SAR exposure were sampled during MRI using multiple fiberoptic temperature sensors. RESULTS: Two catheters (the Arrow StimuCath Peripheral Nerve and B. Braun Medical Perifix FX Epidural) were found to be magnetic and not tested further. At 3 T, exposure of the remaining 3 epidural and 1 peripheral nerve catheter to the scanner's maximum RF exposure elicited anomalous heating of 4°C to 7°C in 2 Arrow Epidural (MultiPort and Flex-Tip Plus) catheters at the entry points. Temperature increases for the other catheters at 3 T, and all catheters at 1.5 T were 1.4°C or less. When normalized to the body-average US Food and Drug Administration guideline SAR of 4 W/kg, maximum projected temperature increases were 0.1°C to 2.5°C at 1.5 T and 0.7°C to 2.7°C at 3 T, except for the Arrow MultiPort Flex-Tip Plus catheter at 3 T whose increase was 14°C. CONCLUSIONS: Most but not all catheters can be left in place during 1.5-T MRI scans. Heating of less than 3°C during MRI for most catheters is not expected to be injurious. While heating was lower at 1.5 T versus 3 T, performance differences between products underscore the need for safety testing before performing MRI.

Curriculum development for an advanced regional anesthesia education program: one institution's experience from apprenticeship to comprehensive teaching.

Results of recent attitude survey studies suggest that most practicing physicians are inadequately treating postoperative pain. Residents in anesthesia are confident in performing lumbar epidural and spinal anesthesia, but many are not confident in performing the blocks with which they have the least exposure. Changes need to be made in the training processes to a comprehensive model that prepares residents to perform a wider array of blocks in postgraduate practice. Here, we describe one institution's approach to creating a standardized, advanced regional anesthesia curriculum for residents that follows the six core competencies of the ACGME. Residents received training in anatomy dissection, ultrasound-guided regional anesthesia, traditional nerve stimulation techniques, problem-based learning and simulation sessions, oral board presentation sessions, and journal club sessions. Residents kept a detailed log for their use of peripheral nerve block procedures. We have now redesigned and implemented an advanced regional anesthesia program within our institution to provide residents with experience in regional anesthesia at a competent level. Resident's knowledge in regional anesthesia did improve after the first year of implementation as reflected in improvements between the pre- and post-tests. As the advanced regional anesthesia education program continues to improve, we hope to demonstrate levels of validity, reliability, and usability by other programs.

Improved residents' knowledge after an advanced regional anesthesia education program.

BACKGROUND: Although residents in anesthesia are confident in performing neuraxial anesthesia, many are not confident in performing peripheral nerve blocks. The purpose of this study was to evaluate the effectiveness of a structured regional anesthesia teaching program in a large academic medical center. METHODS: Residents participated in regional anesthesia didactics that took place in a unique resident education program scheduled during two fully protected teaching days a month. The curriculum included hands-on cadaver workshops in the anatomy lab, hands-on ultrasound workshops, hands-on nerve stimulator and surface anatomy workshops, and simulator sessions related to complications of regional anesthesia. Before beginning the formal regional anesthesia teaching program, residents completed a pretest composed of 25 multiple choice questions (MCQ) and a three-section observed standardized clinical examination (OSCE). Seven months later, approximately 1 month after completion of the regional anesthesia curriculum, the residents were evaluated again with the exact same tests. Pretest and post-test results for both the MCQ and the OSCE were compared by using a paired t-test for statistical means. RESULTS: Post-test results were significantly improved (P < 0.05) across all clinical anesthesia (CA) years and for both the MCQ and OSCE examinations. Post-test results were also significantly improved (P < 0.05) across all CA years for each of the three sections of the OSCE. CONCLUSION: The formal regional anesthesia teaching program developed by the departmental faculty was effective in improving resident knowledge.

Special anesthetic consideration for the patient with a fragility fracture.

In this article, an overview is presented of perioperative management of the patient with a fragility fracture, including preoperative risk stratification and optimization, anesthesia risks, anesthesia options, and postoperative pain management. Issues of preoperative evaluation that are of concern for the anesthesiologist because of their direct effect on intraoperative care are discussed. A team interdisciplinary approach and good communication between specialties involved in care of elderly surgical patients is important for optimal patient outcomes and to avoid perioperative complications. Cooperation between anesthesiology and medicine is indispensable in reaching a reasonable consensus regarding preoperative evaluation and should occur on a case-by-case basis.

Analgesic efficacy of continuous intravenous magnesium infusion as an adjuvant to morphine for postoperative analgesia: a systematic review and meta-analysis.

BACKGROUND: The efficacy of perioperative intravenous magnesium administration on postoperative opioid use, opioid-related side effects (e.g., nausea and vomiting) and pain are uncertain, as randomized controlled trials on this topic have reported disparate results. The objective of this systematic review is to determine if perioperative magnesium reduces opioid use, opioid-related side effects, and postoperative pain. METHODS: An electronic search was conducted using the Library of Medicine's PubMed and EMBASE databases. Included studies consisted of randomized controlled trials in an adult population with a clearly defined comparison of perioperative intravenous magnesium administration to a control with a documented assessment of opioid usage and postoperative pain. Relevant data was abstracted from included studies. Pooled estimates for weighted mean difference (WMD) with 95% confidence intervals (CI) were obtained for our primary outcome (opioid usage) using the Cochrane Collaboration's RevMan version 4.2.7 (Cochrane Collaboration; Oxford, United Kingdom). WMD and odds ratios (OR) were calculated using a random effects model. RESULTS: The literature search ultimately yielded 22 trials, enrolling 1177 (599 magnesium, 578 control) patients, who were included in the analysis. A significant decrease in morphine usage by those patients who received magnesium was noted (WMD = -7.40; 95% CI: -9.40 to -5.41, p < 0.00001). Perioperative magnesium administration was not associated with a difference in postoperative nausea or vomiting (RR = 0.76; 95% CI: 0.52 to 1.09, p = 0.14). The pooled visual analog scores for pain at 4-6 hours after surgery were significantly less in those patients who received magnesium surgery (WMD = -0.67; 95% CI: -1.12 to -0.23, p = 0.003); however, there was no difference in pain scores at 20-24 hours after surgery (WMD = -0.25; 95% CI: -0.62 to 0.71, p = 0.17). CONCLUSION: Based on the results of this systematic review, perioperative intravenous magnesium may be a useful adjuvant for the management of postoperative pain providing analgesia through a different mechanism of action than that of opioids and would make a potential addition to a multimodal anlgesic treatment plan; however, the decrease in opioid use with perioperative magnesium infusion does not appear to be associated with a decresea in opioid-related side effects.

Analgesic efficacy of intravenous naloxone for the treatment of postoperative pruritus: a meta-analysis.

OBJECTIVES: Pruritus may be a significant problem for patients in the postoperative period. There are many options for the treatment of pruritus including intravenous (IV) naloxone. However, it is not clear whether the use of IV naloxone may also affect analgesia or other opioid-related side effects. The authors have performed a systematic review to further examine this issue. METHODS: Systematic literature searches of the National Library of Medicine's PubMed and EMBASE databases were conducted using terms related to postoperative use of IV naloxone. Only randomized controlled trials comparing IV naloxone used either as a continuous infusion or part of an IV patient-controlled analgesia (PCA) regimen after surgical procedures were considered. The data on pertinent study characteristics and relevant outcomes were extracted from accepted articles. There was no restriction on language for inclusion. Meta-analysis was performed using the Review Manager 4.2.10 (The Cochrane Collaboration, 2004). A random effects model was used. RESULTS: The literature searches yielded eight articles that met all inclusion criteria. There were a total of 424 subjects in the naloxone group and 376 in the saline group. The authors found that the use of naloxone was associated with a decreased risk for pruritus (odds ratio [OR] = 0.40, 95% confidence interval [CI] = 0.21-0.79, p = 0.006] and nausea [OR = 0.62, 95% CI = 0.43-0.89, p = 0.009]. However, the use of IV naloxone (vs no naloxone) did not significantly influence the risk of postoperative emesis [OR = 0.97, 95% CI = 0.70-1.33, p = 0.83], opioid consumption [OR = 0.29, 95% CI = -3.54-4.13, p = 0.88], or sedation [OR = 0.82, 95% CI = 0.38-1.74, p = 0.60]. Finally, the use of IV naloxone did not appear to be associated with any significant change in visual analog score pain scores at 24 hours postoperatively (weighted mean difference = -0.14, 95% CI = -0.50-0.23, p = 0.46). CONCLUSIONS: Our pooled analysis examining the analgesic efficacy of IV naloxone (either as a continuous infusion or IV PCA) revealed that naloxone was associated with a decrease in pruritus and nausea without any increase in pain scores. When compared with controls, the use of IV naloxone was not associated with any significant changes in opioid consumption or with the risk of sedation or emesis.

Analgesic efficacy of ultrasound-guided regional anesthesia: a meta-analysis.

STUDY OBJECTIVE: To determine if the use of ultrasound guidance (vs non-ultrasound techniques) improves the success rate of nerve blocks. DESIGN: Meta-analysis of randomized controlled trials (RCTs) in the published literature. SETTING: University medical center. MEASUREMENTS: 16 RCTs of patients undergoing elective surgical procedures were studied. Patients underwent ultrasound-guided or non-ultrasound techniques (nerve stimulation, surface landmark) for peripheral nerve blocks. Success rates were measured. MAIN RESULTS: Ultrasound guidance (vs all non-ultrasound techniques) was associated with a significant increase in the success rate of nerve blocks [relative risk (RR) = 1.11 (95% confidence interval [CI]: 1.06 to 1.17, P < 0.0001]). When compared with nerve stimulator techniques only, ultrasound guidance was still associated with an increase in the success rate (RR = 1.11 [95% CI: 1.05 to 1.17, P = 0.0001]). For specific blocks, ultrasound guidance (vs all non-ultrasound) was associated with a significant increase in successful brachial plexus (all) nerve blocks (RR = 1.11 [95% CI: 1.05 to 1.20, P = 0.0001]), sciatic popliteal nerve block (RR = 1.22 [95% CI: 1.08 to 1.39, P = 0.002]) and brachial plexus axillary nerve block (RR = 1.13 [95% CI: 1.00 to 1.26, P = 0.05]) but not brachial plexus infraclavicular nerve block (RR = 1.25 [95% CI: 0.88 to 1.76, P = 0.22]). CONCLUSIONS: Ultrasound-guided peripheral nerve block is associated with an increased overall success rate when compared with nerve stimulation or other methods. Ultrasound-guided techniques also increase the success rate of some specific blocks.