Autonomic Neuromodulation for Atrial Fibrillation Following Cardiac Surgery: JACC Review Topic of the Week.

Autonomic neuromodulation therapies (ANMTs) (ie, ganglionated plexus ablation, epicardial injections for temporary neurotoxicity, low-level vagus nerve stimulation [LL-VNS], stellate ganglion block, baroreceptor stimulation, spinal cord stimulation, and renal nerve denervation) constitute an emerging therapeutic approach for arrhythmias. Very little is known about ANMTs' preventive potential for postoperative atrial fibrillation (POAF) after cardiac surgery. The purpose of this review is to summarize and critically appraise the currently available evidence. Herein, the authors conducted a systematic review of 922 articles that yielded 7 randomized controlled trials. In the meta-analysis, ANMTs reduced POAF incidence (OR: 0.37; 95% CI: 0.25 to 0.55) and burden (mean difference [MD]: -3.51 hours; 95% CI: -6.64 to -0.38 hours), length of stay (MD: -0.82 days; 95% CI: -1.59 to -0.04 days), and interleukin-6 (MD: -79.92 pg/mL; 95% CI: -151.12 to -8.33 pg/mL), mainly attributed to LL-VNS and epicardial injections. Moving forward, these findings establish a base for future larger and comparative trials with ANMTs, to optimize and expand their use.

Preoperative Paravertebral Block and Chronic Pain after Breast Cancer Surgery: A Double-blind Randomized Trial.

BACKGROUND: The effectiveness of paravertebral block in preventing chronic pain after breast surgery remains controversial. The primary hypothesis of this study was that paravertebral block reduces the incidence of chronic pain 3 months after breast cancer surgery. METHODS: In this prospective, multicenter, randomized, double-blind, parallel-group, placebo-controlled study, 380 women undergoing partial or complete mastectomy with or without lymph node dissection were randomized to receive preoperative paravertebral block with either 0.35 ml/kg 0.75% ropivacaine (paravertebral group) or saline (control group). Systemic multimodal analgesia was administered in both groups. The primary endpoint was the incidence of chronic pain with a visual analogue scale (VAS) score greater than or equal to 3 out of 10, 3 months after surgery. The secondary outcomes were acute pain, analgesic consumption, nausea and vomiting, chronic pain at 6 and 12 months, neuropathic pain, pain interference, anxiety, and depression. RESULTS: Overall, 178 patients received ropivacaine, and 174 received saline. At 3 months, chronic pain was reported in 93 of 178 (52.2%) and 83 of 174 (47.7%) patients in the paravertebral and control groups, respectively (odds ratio, 1.20 [95% CI, 0.79 to 1.82], P = 0.394). At 6 and 12 months, chronic pain occurred in 104 of 178 (58.4%) versus 79 of 174 (45.4%) and 105 of 178 (59.0%) versus 93 of 174 (53.4%) patients in the paravertebral and control groups, respectively. Greater acute postoperative pain was observed in the control group 0 to 2 h (area under the receiver operating characteristics curve at rest, 4.3 ± 2.8 vs. 2.9 ± 2.8 VAS score units × hours, P < 0.001) and when maximal in this interval (3.8 ± 2.1 vs. 2.5 ± 2.5, P < 0.001) but not during any other interval. Postoperative morphine use was 73% less in the paravertebral group (odds ratio, 0.272 [95% CI, 0.171 to 0.429]; P < 0.001). CONCLUSIONS: Paravertebral block did not reduce the incidence of chronic pain after breast surgery. Paravertebral block did result in less immediate postoperative pain, but there were no other significant differences in postoperative outcomes.

Peripheral Nerve Blocks and Potentially Attributable Adverse Events in Older People with Hip Fracture: A Retrospective Population-based Cohort Study.

BACKGROUND: Peripheral nerve blocks are being used with increasing frequency for management of hip fracture-related pain. Despite converging evidence that nerve blocks may be beneficial, safety data are lacking. This study hypothesized that peripheral nerve block receipt would not be associated with adverse events potentially attributable to nerve blocks, as well as overall patient safety incidents while in hospital. METHODS: This was a preregistered, retrospective population-based cohort study using linked administrative data. This study identified all hip fracture admissions in people 50 yr of age or older and identified all nerve blocks (although we were unable to ascertain the specific anatomic location or type of block), potentially attributable adverse events (composite of seizures, fall-related injuries, cardiac arrest, nerve injury), and any patient safety events using validated codes. The study also estimated the unadjusted and adjusted association of nerve blocks with adverse events; adjusted absolute risk differences were also calculated. RESULTS: In total, 91,563 hip fracture patients from 2009 to 2017 were identified; 15,631 (17.1%) received a nerve block, and 5,321 (5.8%; 95% CI, 5.7 to 6.0%) patients experienced a potentially nerve block-attributable adverse event: 866 (5.5%) in patients with a block and 4,455 (5.9%) without a block. Before and after adjustment, nerve blocks were not associated with potentially attributable adverse events (adjusted odds ratio, 1.05; 95% CI, 0.97 to 1.15; and adjusted risk difference, 0.3%, 95% CI, -0.1 to 0.8). CONCLUSIONS: The data suggest that nerve blocks in hip fracture patients are not associated with higher rates of potentially nerve block-attributable adverse events, although these findings may be influenced by limitations in routinely collected administrative data.

Trends in Peripheral Nerve Block Usage in Mastectomy and Lumpectomy: Analysis of a National Database From 2010 to 2018.

BACKGROUND: Compared to general anesthesia, regional anesthesia confers several benefits including improved pain control and decreased postoperative opioid consumption. While the benefits of peripheral nerve blocks (PNB) have been well studied, there are little epidemiological data on PNB usage in mastectomy and lumpectomy procedures. The primary objective of our study was to assess national trends of the annual proportion of PNB use in breast surgery from 2010 to 2018. We also identified factors associated with PNB use for breast surgery. METHODS: We identified lumpectomy and mastectomy surgical cases with and without PNB between 2010 and 2018 using the Anesthesia Quality Institute National Anesthesia Clinical Outcomes Registry (AQI NACOR). We modeled the nonlinear association between year of procedure and PNB use with segmented mixed-effects logistic regression clustered on facility identifier. The association between PNB use and year of procedure, age, sex, American Society of Anesthesiologists physical status (ASA PS), facility type, facility region, weekday, and tissue expander use was also modeled using mixed-effects logistic regression. RESULTS: Of the 189,854 surgical cases from 2010 to 2018 that met criteria, 86.2% were lumpectomy cases and 13.8% were mastectomy cases. The proportion of lumpectomy cases with PNB was <0.1% in 2010 and increased each subsequent year to 1.9% in 2018 (trend P < .0001). The proportion of mastectomy cases with PNB was 0.5% in 2010 and 13% in 2018 (trend P < .0001). The year 2014 was the breakpoint selected for segmented regression. Before 2014, the odds of PNB among the mastectomy cases was not significantly different from year to year. After 2014, the odds of PNB increased by 2.24-fold each year (95% confidence interval [CI], 2.00-2.49; P < .001); interaction test for pre-2014 versus post-2014 was P < .001. Similar trends were seen in the lumpectomy cases, where after 2014, the odds of PNB increased by 2.03-fold (95% CI, 1.81-2.27; P < .001); interaction test for pre-2014 versus post-2014 was P < .001. In the mastectomy cohort, year of procedure ≥2014, female sex, facility region, and tissue expander use were associated with higher odds of PNB. For lumpectomy cases, year of procedure ≥2014 and facility region were associated with higher odds of PNB use. CONCLUSIONS: We found increased annual utilization of PNB for mastectomy and lumpectomy since 2010, although absolute prevalence is low. PNB use was associated with year of procedure for both lumpectomy and mastectomy, particularly post-2014.

Factors associated with rebound pain after peripheral nerve block for ambulatory surgery.

BACKGROUND: Rebound pain is a common, yet under-recognised acute increase in pain severity after a peripheral nerve block (PNB) has receded, typically manifesting within 24 h after the block was performed. This retrospective cohort study investigated the incidence and factors associated with rebound pain in patients who received a PNB for ambulatory surgery. METHODS: Ambulatory surgery patients who received a preoperative PNB between March 2017 and February 2019 were included. Rebound pain was defined as the transition from well-controlled pain (numerical rating scale [NRS] ≤3) while the block is working to severe pain (NRS ≥7) within 24 h of block performance. Patient, surgical, and anaesthetic factors were analysed for association with rebound pain by univariate, multivariable, and machine learning methods. RESULTS: Four hundred and eighty-two (49.6%) of 972 included patients experienced rebound pain as per the definition. Multivariable analysis showed that the factors independently associated with rebound pain were younger age (odds ratio [OR] 0.98; 95% confidence interval [CI] 0.97-0.99), female gender (OR 1.52 [1.15-2.02]), surgery involving bone (OR 1.82 [1.38-2.40]), and absence of perioperative i.v. dexamethasone (OR 1.78 [1.12-2.83]). Despite a high incidence of rebound pain, there were high rates of patient satisfaction (83.2%) and return to daily activities (96.5%). CONCLUSIONS: Rebound pain occurred in half of the patients and showed independent associations with age, female gender, bone surgery, and absence of intraoperative use of i.v. dexamethasone. Until further research is available, clinicians should continue to use preventative strategies, especially for patients at higher risk of experiencing rebound pain.

The relative analgesic value of a femoral nerve block versus adductor canal block following total knee arthroplasty: a randomized, controlled, double-blinded study.

BACKGROUND: Multiple comparative studies report that adductor canal blocks provide similar pain relief to femoral nerve blocks following total knee arthroplasty. However, adductor canal blockade fails to anesthetize several important femoral nerve branches that contribute to knee innervation. We sought to clarify this anatomic discrepancy by performing both blocks in sequence, using patients as their own controls. We hypothesized that patients would experience additional pain relief following a superimposed femoral nerve block, demonstrating that these techniques are not equivalent. METHODS: Sixteen patients received continuous adductor canal block before undergoing knee arthroplasty under general anesthesia. In the recovery room, patients reported their pain score on a numeric scale of 0-10. Once a patient reached a score of five or greater, he/she was randomized to receive an additional femoral nerve block using 2% chloroprocaine or saline sham, and pain scores recorded every 5 min for 30 min. Patients received opioid rescue as needed. Anesthesiologists performing and assessing block efficacy were blinded to group allocation. RESULTS: Patients randomized to chloroprocaine versus saline reported significantly improved median pain scores 30 min after the femoral block (2.0 vs. 5.5, P = 0.0001). Patients receiving chloroprocaine also required significantly fewer morphine equivalents during the 30 min post-femoral block (1.0 vs. 4.5 mg, P = 0.03). CONCLUSIONS: Adductor canal block is a useful technique for postoperative pain following total knee arthroplasty, but it does not provide equivalent analgesic efficacy to femoral nerve block. Future studies comparing efficacy between various block sites along the thigh are warranted.

Daring discourse: are we ready to recommend neuraxial anesthesia and peripheral nerve blocks during the COVID-19 pandemic? A pro-con.

The recent joint statement from the American Society of Regional Anesthesia and Pain Medicine (ASRA) and the European Society of Regional Anesthesia and Pain Therapy (ESRA) recommends neuraxial and peripheral nerve blocks for patients with coronavirus disease 2019 (COVID-2019) illness. The benefits of regional anesthetic and analgesic techniques on patient outcomes and healthcare systems are evident. Regional techniques are now additionally promoted as a mechanism to reduce aerosolizing procedures. However, caring for patients with COVID-19 illness requires rapid redefinition of risks and benefits-both for patients and practitioners. These should be fully considered within the context of available evidence and expert opinion. In this Daring Discourse, we present two opposing perspectives on adopting the ASRA/ESRA recommendation. Areas of controversy in the literature and opportunities for research to address knowledge gaps are highlighted. We hope this will stimulate dialogue and research into the optimal techniques to improve patient outcomes and ensure practitioner safety during the pandemic.

A Population-based Comparative Effectiveness Study of Peripheral Nerve Blocks for Hip Fracture Surgery.

BACKGROUND: Adverse outcomes and resource use rates are high after hip fracture surgery. Peripheral nerve blocks could improve outcomes through enhanced analgesia and decreased opioid related adverse events. We hypothesized that these benefits would translate into decreased resource use (length of stay [primary outcome] and costs), and better clinical outcomes (pneumonia and mortality). METHODS: The authors conducted a retrospective cohort study of hip fracture surgery patients in Ontario, Canada (2011 to 2015) using linked health administrative data. Multilevel regression, instrumental variable, and propensity scores were used to determine the association of nerve blocks with resource use and outcomes. RESULTS: The authors identified 65,271 hip fracture surgery patients; 10,030 (15.4%) received a block. With a block, the median hospital stay was 7 (interquartile range, 4 to 13) days versus 8 (interquartile range, 5 to 14) days without. Following adjustment, nerve blocks were associated with a 0.6-day decrease in length of stay (95% CI, 0.5 to 0.8). This small difference was consistent with instrumental variable (1.1 days; 95% CI, 0.9 to 1.2) and propensity score (0.2 days; 95% CI, 0.2 to 0.3) analyses. Costs were lower with a nerve block (adjusted difference, -$1,421; 95% CI, -$1,579 to -$1,289 [Canadian dollars]), but no difference in mortality (adjusted odds ratio, 0.99; 95% CI, 0.89 to 1.11) or pneumonia (adjusted odds ratio, 1.01; 95% CI, 0.88 to 1.16) was observed. CONCLUSIONS: Receipt of nerve blocks for hip fracture surgery is associated with decreased length of stay and health system costs, although small effect sizes may not reflect clinical significance for length of stay.

Peripheral Nerve Blocks for Ambulatory Shoulder Surgery: A Population-based Cohort Study of Outcomes and Resource Utilization.

BACKGROUND: Nerve blocks improve early pain after ambulatory shoulder surgery; impact on postdischarge outcomes is poorly described. Our objective was to measure the association between nerve blocks and health system outcomes after ambulatory shoulder surgery. METHODS: We conducted a population-based cohort study using linked administrative data from 118 hospitals in Ontario, Canada. Adults having elective ambulatory shoulder surgery (open or arthroscopic) from April 1, 2009, to December 31, 2016, were included. After validation of physician billing codes to identify nerve blocks, we used multilevel, multivariable regression to estimate the association of nerve blocks with a composite of unplanned admissions, emergency department visits, readmissions or death within 7 days of surgery (primary outcome) and healthcare costs (secondary outcome). Neurology consultations and nerve conduction studies were measured as safety indicators. RESULTS: We included 59,644 patients; blocks were placed in 31,073 (52.1%). Billing codes accurately identified blocks (positive likelihood ratio 16.83, negative likelihood ratio 0.03). The composite outcome was not significantly different in patients with a block compared with those without (2,808 [9.0%] vs. 3,424 [12.0%]; adjusted odds ratio 0.96; 95% CI 0.89 to 1.03; P = 0.243). Healthcare costs were greater with a block (adjusted ratio of means 1.06; 95% CI 1.02 to 1.10; absolute increase $325; 95% CI $316 to $333; P = 0.005). Prespecified sensitivity analyses supported these results. Safety indicators were not different between groups. CONCLUSIONS: In ambulatory shoulder surgery, nerve blocks were not associated with a significant difference in adverse postoperative outcomes. Costs were statistically higher with a block, but this increase is not likely clinically relevant.

Effects of Thoracic Epidural Anesthesia on Neuronal Cardiac Regulation and Cardiac Function.

Cardiac sympathetic blockade with high-thoracic epidural anesthesia is considered beneficial in patients undergoing major surgery because it offers protection in ischemic heart disease. Major outcome studies have failed to confirm such a benefit, however. In fact, there is growing concern about potential harm associated with the use of thoracic epidural anesthesia in high-risk patients, although underlying mechanisms have not been identified. Since the latest review on this subject, a number of clinical and experimental studies have provided new information on the complex interaction between thoracic epidural anesthesia-induced sympatholysis and cardiovascular control mechanisms. Perhaps these new insights may help identify conditions in which benefits of thoracic epidural anesthesia may not outweigh potential risks. For example, cardiac sympathectomy with high-thoracic epidural anesthesia decreases right ventricular function and attenuates its capacity to cope with increased right ventricular afterload. Although the clinical significance of this pathophysiologic interaction is unknown at present, it identifies a subgroup of patients with established or pending pulmonary hypertension for whom outcome studies are needed. Other new areas of interest include the impact of thoracic epidural anesthesia-induced sympatholysis on cardiovascular control in conditions associated with increased sympathetic tone, surgical stress, and hemodynamic disruption. It was considered appropriate to collect and analyze all recent scientific information on this subject to provide a comprehensive update on the cardiovascular effects of high-thoracic epidural anesthesia and cardiac sympathectomy in healthy and diseased patients.This review provides a comprehensive update on the cardiovascular effects of high-thoracic epidural anesthesia and cardiac sympathectomy in healthy and diseased patients.

Peripheral nerve blocks are not associated with increased risk of perioperative peripheral nerve injury in a Veterans Affairs inpatient surgical population.

BACKGROUND AND OBJECTIVES: Perioperative peripheral nerve injury (PNI) is a known complication in patients undergoing surgery with or without regional anesthesia. The incidence of new PNI in a Veterans Affairs (VA) inpatient surgical population has not been previously described; therefore, the incidence, risk factors, and clinical course of new PNI in this cohort are unknown. We hypothesized that peripheral nerve blocks do not increase PNI incidence. METHODS: We conducted a 5-year review of a Perioperative Surgical Home database including all consecutive surgical inpatients. The primary outcome was new PNI between groups that did or did not have peripheral nerve blockade. Potential confounders were first examined individually using logistic regression, and then included simultaneously together within a mixed-effects logistic regression model. Electronic records of patients with new PNI were reviewed for up to a year postoperatively. RESULTS: The incidence of new PNI was 1.2% (114/9558 cases); 30 of 3380 patients with nerve block experienced new PNI (0.9%) compared with 84 of 6178 non-block patients (1.4%; p=0.053). General anesthesia alone, younger age, and American Society of Anesthesiologists physical status <3 were associated with higher incidence of new PNI. Patients who received transversus abdominis plane blocks had increased odds for PNI (OR, 3.20, 95% CI 1.34 to 7.63), but these cases correlated with minimally invasive general and urologic surgery. One hundred PNI cases had 1-year follow-up: 82% resolved by 3 months and only one patient did not recover in a year. CONCLUSIONS: The incidence of new perioperative PNI for VA surgical inpatients is 1.2% and the use of peripheral nerve blocks is not an independent risk factor.

Adjunct medications for peripheral and neuraxial anesthesia.

Regional and neuraxial anesthesia can provide a safer perioperative experience, greater satisfaction, reduced opioid consumption, and reduction of pain, while minimizing side effects. Ultrasound technology has aided clinicians in depositing local anesthetic medication in precise proximity to targeted peripheral nerves. There are a plethora of adjuvants that have been utilized to prolong local anesthetic actions and enhance effects in peripheral nerve blocks. This manuscript describes the current state of the use of adjuncts, e.g., dexmedetomidine, dexamethasone, clonidine, epinephrine, etc., in regional anesthesia. Additionally, evidence behind dosing and block prolongation is summarized along with patient outcomes, adverse effects, and future directions.

Effect of local infiltration analgesia, peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in total knee arthroplasty.

BACKGROUND: Postoperative pain control and enhanced mobilization, muscle strength and range of motion following total knee arthroplasty (TKA) are pivotal requisites to optimize rehabilitation and early recovery. The aim of the study was to analyze the effect of local infiltration analgesia (LIA), peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in primary total knee arthroplasty. METHODS: Between January 2016 until August 2016, 280 patients underwent primary TKA and were subdivided into four groups according to their concomitant pain and anesthetic procedure with catheter-based techniques of femoral and sciatic nerve block (group GA&FNB, n = 81) or epidural catheter (group SP&EPI, n = 51) in combination with general anesthesia or spinal anesthesia, respectively, and LIA combined with general anesthesia (group GA&LIA, n = 86) or spinal anesthesia (group SP&LIA, n = 61). Outcome parameters focused on the evaluation of pain (NRS scores), mobilization, muscle strength and range of motion up to 7 days postoperatively. The cumulative consumption of (rescue) pain medication was analyzed. RESULTS: Pain relief was similar in all groups, while the use of opioid medication was significantly lower (up to 58%) in combination with spinal anesthesia, especially in SP&EPI. The LIA groups, in contrast, revealed significant higher mobilization (up to 26%) and muscle strength (up to 20%) in the early postoperative period. No analgesic technique-related or surgery-related complications occurred within the first 7 days. Due to insufficient pain relief, 8.4% of the patients in the catheter-based groups and 12.2% in the LIA groups resulted in a change of the anesthetics pain management. CONCLUSIONS: The LIA technique offers a safe and effective treatment option concerning early functional recovery and pain control in TKA. Significant advantages were shown for mobilization and muscle strength in the early postoperative period while pain relief was comparable within the groups.

Effect of local infiltration analgesia, peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in unicompartmental knee arthroplasty.

BACKGROUND: The aim of the study was to analyze the effect of local infiltration analgesia (LIA), peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in primary unicompartmental knee arthroplasty (UKA). METHODS: Between January 2016 until August 2016, 134 patients underwent primary UKA and were subdivided into four groups according to their concomitant pain and anesthetic procedure with catheter-based techniques of femoral and sciatic nerve block (group GA&FNB, n = 38) or epidural catheter (group SP&EPI, n = 20) in combination with general anesthesia or spinal anesthesia, respectively, and LIA combined with general anesthesia (group GA&LIA, n = 46) or spinal anesthesia (group SP&LIA, n = 30). Outcome parameters focused on the evaluation of pain (NRS scores), mobilization, muscle strength and range of motion up to 7 days postoperatively. The cumulative consumption of (rescue) pain medication was analyzed. RESULTS: The LIA groups revealed significantly lower (about 50%) mean NRS scores (at rest) compared to the catheter-based groups at the day of surgery. In the early postoperative period, the dose of hydromorphone as rescue pain medication was significantly lower (up to 68%) in patients with SP&EPI compared to all other groups. No significant differences could be detected with regard to grade of mobilization, muscle strength and range of motion. However, there seemed to be a trend towards improved mobilization and muscle strength with general anesthesia and LIA, whereof general anesthesia generally tended to ameliorate mobilization. CONCLUSIONS: Except for a significant lower NRS score at rest in the LIA groups at day of surgery, pain relief was comparable in all groups without clinically relevant differences, while the use of opioids was significantly lower in patients with SP&EPI. A clear clinically relevant benefit for LIA in UKA cannot be stated. However, LIA offers a safe and effective treatment option comparable to the well-established conventional procedures.

Readiness for Discharge After Foot and Ankle Surgery Using Peripheral Nerve Blocks: A Randomized Controlled Trial Comparing Spinal and General Anesthesia as Supplements to Nerve Blocks.

BACKGROUND: Neuraxial anesthesia is often viewed as superior to general anesthesia but may delay discharge. Comparisons do not typically use multimodal analgesics and nerve blockade. Combining nerve blockade with general anesthesia may reduce pain, opioid consumption, and nausea. We hypothesized that general anesthesia (with nerve blocks) would lead to earlier readiness for discharge, compared to spinal anesthesia (with nerve blocks). METHODS: All patients underwent ambulatory foot and ankle surgery, with a predicted case duration of 1-3 hours. All patients received popliteal and adductor canal nerve blocks using bupivacaine and dexamethasone. No intraoperative opioids were administered. All patients received ondansetron, dexamethasone, ketamine, and ketorolac. Patients, data collectors, and the data analyst were not informed of group assignment. Patients were randomized to spinal or general anesthesia with concealed allocation. Spinal anesthesia was performed with mepivacaine and accompanied with propofol sedation. After general anesthesia was induced with propofol, a laryngeal mask airway was inserted, followed by sevoflurane and propofol. Time until ready for discharge, the primary outcome, was compared between groups after adjusting for age and surgery time using multivariable unconditional quantile regression. Secondary outcomes compared at multiple timepoints were adjusted for multiple comparisons using the Holm-Bonferroni step-down procedure. RESULTS: General anesthesia patients were ready for discharge at a median of 39 minutes earlier (95% confidence interval, 2-75; P = .038) versus spinal anesthesia patients. Patients in both groups met readiness criteria for discharge substantially before actual discharge. Pain scores at rest were higher among general anesthesia patients 1 hour after leaving the operating room (adjusted difference in means, 2.1 [95% confidence interval, 1.0-3.2]; P < .001). Other secondary outcomes (including opioid use, opioid side effects, nausea, headache, sore throat, and back pain) were not different. CONCLUSIONS: General anesthesia was associated with earlier readiness for discharge, but the difference may not be clinically significant and did not lead to earlier actual discharge. Most secondary outcomes were not different between groups. The choice of spinal or general anesthesia as an adjunct to peripheral nerve blockade can reflect patient, clinician, and institutional preferences.

Analgesia of Combined Femoral Triangle and Obturator Nerve Blockade Is Superior to Local Infiltration Analgesia After Total Knee Arthroplasty With High-Dose Intravenous Dexamethasone.

BACKGROUND AND OBJECTIVES: High-dose intravenous dexamethasone reduces the postoperative opioid requirement and is often included in the multimodal analgesia strategy after total knee arthroplasty (TKA). Combined obturator nerve and femoral triangle blockade (OFB) reduces the opioid consumption and pain after TKA better than local infiltration analgesia (LIA). The question is whether preoperative high-dose intravenous dexamethasone would cancel out the superior analgesic effect of OFB compared with LIA. The aim was to evaluate the analgesic effect of OFB versus LIA after TKA when all patients received high-dose intravenous dexamethasone. METHODS: Eighty-two patients were randomly assigned either to OFB or LIA after primary unilateral TKA. All patients received 16 mg dexamethasone. Primary outcome was morphine consumption via patient-controlled analgesia during the first 20 postoperative hours. Secondary outcomes were pain, nausea, dizziness, and length of hospital stay. RESULTS: Seventy-four patients were included in the analysis. Median total intravenous morphine consumption during the first 20 postoperative hours was 6 mg (interquartile range [IQR], 2-18 mg) in the OFB group and 20 mg (IQR, 12-28 mg) in the LIA group. The 14-mg difference (95% confidence interval, 6.4-18.0 mg) was significant (P < 0.001). There was no difference in pain score at rest at 20 hours postoperatively: 2 (IQR, 1-4) in the OFB group and 3 (IQR, 2-5) in the LIA group. CONCLUSIONS: Combined OFB reduces morphine consumption better than LIA after TKA even when all patients received high-dose intravenous dexamethasone. CLINICAL TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov, identifier NCT02374008.

Use of Regional Anesthesia for Outpatient Surgery Within the United States: A Prevalence Study Using a Nationwide Database.

BACKGROUND: Regional anesthesia is of benefit for outpatient surgery given its demonstrated improvement in analgesia and decrease in complications, resulting in shorter average recovery room times and lower hospital readmission rates. Unfortunately, there are few epidemiological studies outlining the overall utilization of peripheral nerve blocks (PNBs) in this setting. Therefore, the primary objective of this study was to report the overall utilization of several types of PNBs among all candidate cases in the outpatient setting within the United States. METHODS: We identified all cases from the National Anesthesia Clinical Outcomes Registry that were performed as an outpatient surgery. We reported the frequency of various types of PNBs among all candidate cases, defined as cases that potentially could have received a PNB. Changes in prevalence of PNB utilization from 2010 to 2015 were analyzed by using logistic regression. RESULTS: Of the 12,911,056 outpatient surgeries in the National Anesthesia Clinical Outcomes Registry, 3,297,372 (25.5%) were amenable to a PNB. However, the overall PNB frequency was only 3.3% of the possible cases. The overall utilization for PNB of the brachial plexus, sciatic nerve, and femoral nerve were 6.1%, 1.5%, and 1.9%, respectively. The surgical procedures generating the highest volume of PNBs were shoulder arthroscopies and anterior cruciate ligament reconstruction, in which 41% and 32% received a PNB, respectively. During this time period, there was a significant increase in overall PNB utilization for both single-injection and continuous PNB (P < .0001). However, the proportion of continuous PNB to single-injection PNB did not increase significantly. CONCLUSIONS: While the overall frequency of PNB is relatively low, there was a significant increase in its prevalence during the study period. Regional anesthesia offers significant positive impact for perioperative outcomes and hospital efficiency metrics; however, it is not clear what is limiting its widespread use. Future studies are necessary to identify barriers and disparities in care to implement methods to increase regional anesthesia volume nationwide where beneficial and appropriate.

A Retrospective Study Evaluating the Effect of Low Doses of Perineural Dexamethasone on Ropivacaine Brachial Plexus Peripheral Nerve Block Analgesic Duration.

Objective: Examination of the effectiveness of perineural dexamethasone administered in very low and low doses on ropivacaine brachial plexus block duration. Design: Retrospective evaluation of brachial plexus block duration in a large cohort of patients receiving peripheral nerve blocks with and without perineural dexamethasone in a prospectively collected quality assurance database. Setting: A single academic medical center. Methods: A total of 1,942 brachial plexus blocks placed over a 16-month period were reviewed. Demographics, nerve block location, and perineural dexamethasone utilization and dose were examined in relation to block duration. Perineural dexamethasone was examined as none (0 mg), very low dose (2 mg or less), and low dose (greater than 2 mg to 4 mg). Continuous catheter techniques, local anesthetics other than ropivacaine, and block locations with fewer than 15 subjects were excluded. Associations between block duration and predictors of interest were examined using multivariable regression models. A subgroup analysis of the impact of receiving dexamethasone on block duration within each block type was also conducted using a univariate linear regression approach. Results: A total of 1,027 subjects were evaluated. More than 90% of brachial plexus blocks contained perineural dexamethasone (≤4 mg), with a median dose of 2 mg. Increased block duration was associated with receiving any dose of perineural dexamethasone (P < 0.0001), female gender (P = 0.022), increased age (P = 0.048), and increased local anesthetic dose (P = 0.01). In a multivariable model, block duration did not differ with very low- or low-dose perineural dexamethasone after controlling for other factors (P = 0.420). Conclusion: Perineural dexamethasone prolonged block duration compared with ropivacaine alone; however, duration was not greater with low-dose compared with very low-dose perineural dexamethasone.

Improving Performance by Monitoring the Success Rate of Peripheral Nerve Blocks.

In our hospital, we introduced a system to measure the collective and individual efficacy of brachial plexus and popliteal nerve blocks with the objective to create transparency as an instrument for monitoring and improvement. Initially, individual results were anonymous, but after 1 year anonymity was lifted within the team of anesthesiologists and results are now discussed quarterly. Collective performance of interscalene, supraclavicular, and popliteal blocks improved significantly over time. Sharing and discussing collective and individual performance has resulted in critical self-appraisal and increased willingness to learn from each other and strengthened the team's ambition for further improvement.