Preventive analgesia by local anesthetics: the reduction of postoperative pain by peripheral nerve blocks and intravenous drugs. Anesth Analg. 2013;116:1141-1161. [PMID: 23408672 DOI: 10.1213/ane.0b013e318277a270]

Effects of intravenous lidocaine on postoperative pain and gastrointestinal function recovery following gastrointestinal surgery: a meta-analysis

INTRODUCTION

The full extent of intravenous lidocaine's effectiveness in alleviating postoperative pain and enhancing gastrointestinal function recovery remains uncertain.

EVIDENCE ACQUISITION

We conducted an exhaustive search of databases to identify randomized controlled trials that compared intravenous lidocaine infusion's efficacy to that of a placebo or routine care in patients undergoing gastrointestinal surgery. The primary outcome measure was resting pain scores 24 h postoperatively. We utilized a random-effects model based on the intention-to-treat principle for the overall results.

EVIDENCE SYNTHESIS

This study included twenty-four trials with 1533 patients. Intravenous lidocaine significantly reduced resting pain scores 24 h after gastrointestinal surgery (twenty trials, SMD -0.67, 95% CI -1.09 to -0.24, P=0.002, I2 = 90%). This finding was consistent in subgroup analyses and sensitivity analyses. The benefit was also observed at other resting and moving time points (1, 2, 4, and 12 h) postoperatively. Intravenous lidocaine significantly decreased opioid consumption within 24 h after surgery (eleven trials, SMD: -1.19; 95% CI: -1.99 to -0.39; P=0.003). Intravenous lidocaine also shortened the time to bowel sound (MD: -8.51; 95% CI: -14.59 to -2.44; P=0.006), time to first flatus (MD: -6.00; 95% CI: -9.87 to -2.13; P=0.002), and time to first defecation (MD: -9.77; 95% CI: -17.19 to -2.36; P=0.01).

CONCLUSIONS

Perioperative intravenous lidocaine can alleviate acute pain and expedite gastrointestinal function recovery in patients undergoing gastrointestinal surgery. However, the results should be interpreted with caution due to substantial heterogeneity. Further large-scale studies are necessary to validate these findings.

Regional Anesthesia for Athletes Undergoing Upper Extremity Procedures: Techniques and Considerations

Upper extremity injuries are frequent in athletes which may require surgeries. Regional anesthesia for postoperative analgesia is important to aid recovery, and peripheral nerve blocks for surgical anesthesia enable surgeries to be performed without general anesthetics and their associated adverse effects. The relevant nerve block approaches to anesthetize the brachial plexus for elbow, wrist and hand surgeries are discussed in this article. There is very limited margin for error when performing nerve blocks and multimodal monitoring approach to reduce harm are outlined. Lastly, the importance of obtaining informed consent prior to nerve block procedures should not be overlooked.

Effects of Intratesticular Lidocaine in Pet Rabbits Undergoing Orchiectomy

The use of local anesthetics for castration is both simple and cost-effective, and it may contribute to reducing the anesthetic requirements. Despite its common use in clinical practice, the literature regarding the effects of intratesticular lidocaine in rabbits is limited. In this study, nine rabbits per group were assigned to intratesticularly receive either 2% lidocaine (0.05 mL/kg into each testicle) or an equivalent volume of saline prior to elective orchiectomy. Anesthesia was induced by intranasal administration of ketamine, medetomidine, and butorphanol. During intraoperative assessment, no significant differences in vital parameters (heart rate, respiratory rate, and peripheral saturation of oxygen) were observed between the groups. However, rabbits receiving intratesticular saline displayed a higher incidence of responses to surgical stimuli. Postoperative pain was evaluated using the composite Centro Animali Non Convenzionali Rabbit Scale (CANCRS), revealing a significantly lower score at the initial post-surgery assessment in rabbits treated with intratesticular lidocaine. All subjects exhibited rapid resumption of food intake and fecal output. While all rabbits demonstrated satisfactory perioperative performances, the use of intratesticular lidocaine was associated with a diminished response to surgical stimuli. Consequently, this practice has the potential to reduce the requirement for additional anesthetics or analgesics, promoting faster recovery.

Analgesic efficacy of local infiltration anaesthesia versus femoral nerve block in alleviating postoperative wound pain following total knee arthroplasty: A systematic review and meta-analysis

Total knee arthroplasty (TKA) often involves significant postoperative pain, necessitating effective analgesia. This meta-analysis compares the analgesic efficacy of local infiltration anaesthesia (LIA) and femoral nerve block (FNB) in managing postoperative wound pain following TKA. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this meta-analysis was structured around the PICO framework, assessing studies that directly compared LIA and FNB in TKA patients. A comprehensive search across PubMed, Embase, Web of Science and the Cochrane Library was conducted without time restrictions. Studies were included based on specific criteria such as participant demographics, study design and outcomes like pain scores and opioid consumption. Quality assessment utilized the Cochrane Collaboration's risk of bias tool. The statistical approach was determined based on heterogeneity, with the choice of fixed- or random-effects models guided by the I2 statistic. Sensitivity analysis and evaluation of publication bias using funnel plots and Egger's linear regression test were also conducted. From an initial pool of 1275 articles, eight studies met the inclusion criteria. These studies conducted in various countries from 2007 to 2016. The meta-analysis showed no significant difference in resting and movement-related Visual Analogue Scale scores post-TKA between the LIA and FNB groups. However, LIA was associated with significantly lower opioid consumption. The quality assessment revealed a low risk of bias in most studies, and the sensitivity analysis confirmed the stability of these findings. There was no significant publication bias detected. Both LIA and FNB are effective in controlling postoperative pain in TKA patients, but LIA offers the advantage of lower opioid consumption. Its simplicity, cost-effectiveness and opioid-sparing nature make LIA the recommended choice for postoperative analgesia in knee replacement surgeries.

Advances in Anesthesia for Shoulder Surgery: A Comprehensive Review of Dexmedetomidine-Enhanced Interscalene Brachial Plexus Block

Surgical procedures on the shoulder pose distinctive challenges in managing pain during the perioperative period, underscoring the importance of exploring innovative anesthesia techniques. This comprehensive review article delves into integrating dexmedetomidine, an alpha-2 adrenergic agonist, within interscalene brachial plexus blocks for shoulder surgery. The review initiates by underscoring the pivotal role of effective anesthesia in shoulder surgery and elucidates the rationale behind investigating dexmedetomidine as an adjunct. It meticulously examines the anatomy and physiology of the brachial plexus, emphasizing its critical significance in shoulder surgery. Furthermore, the article expounds on dexmedetomidine's mechanisms of action and pharmacokinetics, encompassing its safety profile and potential side effects. The conventional interscalene brachial plexus block techniques, along with their limitations and challenges, are discussed, laying the foundation for the integration of dexmedetomidine. The review subsequently delves into exploring the role of dexmedetomidine in regional anesthesia, covering previous studies, mechanisms of action, and the potential advantages of incorporating it into nerve blocks. The review's core concentrates on the practical application of dexmedetomidine-enhanced interscalene brachial plexus blocks. This includes discussions on administration techniques, dosage guidelines, and compelling evidence supporting its utilization. Clinical scenarios where this approach proves most advantageous are thoroughly explored, comparing its effectiveness with traditional techniques in terms of pain control and patient outcomes. A comprehensive examination of relevant clinical trials and case studies highlights the evidence supporting its efficacy. The review also underscores safety considerations associated with dexmedetomidine. It proposes strategies for mitigating risks to ensure patient safety. Insights into future directions and research are provided, encompassing ongoing studies, areas necessitating further investigation, and potential refinements in technique. Finally, the article summarizes key findings, emphasizing the practicality of dexmedetomidine-enhanced interscalene brachial plexus blocks in shoulder surgery and its far-reaching implications for clinical practice and patient care.

Deep Neuromuscular Block Attenuates Chronic Postsurgical Pain and Enhances Long-Term Postoperative Recovery After Spinal Surgery: A Randomized Controlled Trial

INTRODUCTION

The effects of deep neuromuscular block (DNMB) on chronic postsurgical pain (CPSP) have not been conclusively determined. Moreover, a limited number of studies have examined the impact of DNMB on long-term recovery quality after spinal surgery. We investigated the impact of DNMB on CPSP and the quality of long-term recovery in patients who had been subjected to spinal surgery.

METHODS

This was a randomized, controlled, double-blind, single-center study performed from May 2022 to November 2022. A total of 220 patients who underwent spinal surgery under general anesthesia were randomly assigned to receive either DNMB (post-tetanic count at 1-2) (the D group) or moderate NMB (MNMB) (train-of-four at 1-3) (the M group). The primary endpoint was the incidence of CPSP. The secondary endpoints included the visual analogue scale (VAS) score in the post-anesthesia recovery unit (PACU), at 12, 24, 48 h and 3 months after surgery; postoperative opioid consumption; quality of recovery-15 (QoR-15) scores on the second postoperative day, before discharge, and 3 months after surgery.

RESULTS

The incidence of CPSP was significantly lower in the D group (30/104, 28.85%) than in the M group (45/105, 42.86%) (p = 0.035). Besides, VAS scores were significantly reduced at the third month in the D group (p = 0.016). In the PACU and 12 h after surgery, VAS scores were also significantly lower in the D group than in the M group (p < 0.001, p = 0.004, respectively). The total amount of postoperative opioid consumption (expressed in total oral morphine equivalents) was significantly less in D group than M group (p = 0.027). At 3 months after surgery, QoR-15 scores were significantly higher in D group than M group (p = 0.003).

CONCLUSIONS

Compared with MNMB, DNMB significantly reduced CPSP and postoperative opioid consumption in spinal surgery patients. Moreover, DNMB improved the long-term recovery of patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR2200058454).

Efficacy of bi-level erector spinae plane block versus bi-level thoracic paravertebral block for postoperative analgesia in modified radical mastectomy: a prospective randomized comparative study

BACKGROUND

Postoperative analgesia in breast surgery is difficult due to the extensive nature of the surgery and the complex innervation of the breast; general anesthesia can be associated with regional anesthesia techniques to control intra- and post-postoperative pain. This randomized comparative study aimed to compare the efficacy of the erector spinae plane block and the thoracic paravertebral block in radical mastectomy procedures with or without axillary emptying.

METHODS

This prospective randomized comparative study included 82 adult females who were randomly divided into two groups using a computer-generated random number. Both groups, Thoracic Paraverterbal block group and Erector Spinae Plane Block group (41 patients each), received general anesthesia associated with a multilevel single-shot thoracic paravertebral block and a multilevel single-shot erector spinae plane block, respectively. Postoperative pain intensity (expressed as Numeric Rating Scale), patients who needed rescue analgesic, intra- and post-operative opioid consumption, post-operative nausea and vomiting, length of stay, adverse events, chronic pain at 6 months, and the patient's satisfaction were recorded.

RESULTS

At 2 h (p < 0.001) and 6 h (p = 0.012) the Numeric Rating Scale was significantly lower in Thoracic Paraverterbal block group. The Numeric Rating Scale at 12, 24, and 36 postoperative hours did not show significant differences. There were no significant differences also in the number of patients requiring rescue doses of NSAIDs, in intra- and post-operative opioid consumption, in post-operative nausea and vomiting episodes and in the length of stay. No failures or complications occurred in the execution of techniques and none of the patients reported any chronic pain at six months from the surgery.

CONCLUSIONS

Both thoracic paravertebral block and erector spinae plane block can be effectively used in controlling post-mastectomy pain with no significant differences between the two blocks.

TRIAL REGISTRATION

The study was prospectively registered on Clinicaltrials.gov (trial identifier NCT04457115) (first registration 27/04/2020).

Appropriate Duration of Perioperative Intravenous Administration of Lidocaine to Provide Satisfactory Analgesia for Adult Patients Undergoing Colorectal Surgery: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Perioperative lidocaine infusion has been reported to alleviate pain intensity after colorectal surgery. However, there is no consensus on whether prolonged lidocaine infusion is more effective than short lidocaine infusion. This meta-analysis aimed to determine an appropriate duration of lidocaine infusion in patients undergoing colorectal surgery.

METHODS

We searched the PubMed, EMBASE, Web of Science, and Cochrane Library databases to identify articles published before December 17, 2021. Randomized controlled trials comparing intravenous lidocaine with placebo for pain relief in patients undergoing colorectal surgery were included. The primary outcome was pain scores (visual analog scale [VAS], 0-10 cm) at 24 hours postoperatively at rest and on movement. Secondary outcomes included pain scores at 12, 48, and 72 hours postoperatively, analgesic consumption (mg), gastrointestinal function return (hour), length of hospital stay (days), and incidence of complications. According to the duration of lidocaine infusion, studies were grouped into infusion for at least 24 hours (prolonged lidocaine infusion) and less than 24 hours (short lidocaine infusion) to assess the impact of lidocaine infusion duration on the outcomes of interests. Quantitative analyses were performed using a random effects model.

RESULTS

Eleven studies with 548 patients were included. Five studies used prolonged lidocaine infusion, while 6 studies used short lidocaine infusion. Prolonged lidocaine infusion reduced postoperative pain scores versus placebo at 24 hours at rest (mean difference [MD], -0.91 cm; 95% confidence interval [CI], -1.54 to -0.28; P = .02) and on movement (MD, -1.69 cm; 95% CI, -2.15 to -1.22; P < .001), while short lidocaine infusion showed no benefit. Compared with placebo, prolonged lidocaine infusion reduced pain scores at 12 hours at rest and at 12 and 48 hours on movement, but short lidocaine infusion did not. However, there was no significant difference in pain scores between the prolonged and short lidocaine infusion groups at these time points. Compared with placebo, prolonged lidocaine infusion shortened the length of hospital stay (MD, -1.30 days; 95% CI, -1.72 to -0.88; P < .001) and time to first postoperative defecation (MD, -12.51 hours; 95% CI, -22.67 to -2.34; P = .02). There were no differences between groups regarding the other outcomes.

CONCLUSIONS

The analgesic effect of intravenous lidocaine may depend on the duration of infusion, and our results suggest that lidocaine infusion should be administered for at least 24 hours after colorectal surgery. Since overall evidence quality was low, further high-quality, large-sample trials are needed to explore an optimal lidocaine infusion strategy in patients undergoing colorectal surgery.

Intraoperative lidocaine infusion as a sole analgesic agent versus morphine in laparoscopic gastric bypass surgery

Background

The aim of this study was to assess the effect of intra-operative intra-venous (IV) lidocaine infusion compared to IV morphine, on the post-operative pain at rest, the intra-operative and post-operative morphine requirements, the sedation and the Modified Aldrete scores in the post-anesthesia care unit (PACU), the hemodynamic parameters; mean values of the mean blood pressure (MBP) and the heart rate (HR), the peri-operative changes in the SpO2, and the respiratory rate (RR) in laparoscopic Roux-en-y gastric bypass. Sixty patients ˃ 18 years old, with body mass index (BMI) ˃ 35 kg/m2, American Society of Anesthesiologists (ASA) physical status II or III, were randomly divided into 2 groups: the lidocaine (L) group patients received intra-operative IV lidocaine infusion, and the morphine (M) group patients received intra-operative IV morphine.

Results

The post-operative numeric pain rating scale (NPRS) at rest was statistically significant less in group L than in group M patients, in the post-operative 90 min in the PACU. This was reflected on the post-operative morphine requirements in the PACU, as 26.6% of patients in group M required morphine with a mean total dose of 10.8 mg. The mean values of the MBP and HR recorded after intubation were comparable between patients of both groups, indicating attenuation of the stress response to endotracheal intubation by both lidocaine and morphine. However, the mean values of the MBP and HR recorded after extubation were statistically significant lower in patients of group L, indicating the attenuation of the stress response to extubation by lidocaine. Patients in group M showed statistically significant lower mean values of the MBP; before pneumoperitoneum and after 15 min from the pneumoperitoneum, this was reflected on statistically significant higher mean values of the HR. Patients in group L showed statistically significant lower mean values of the MBP and the HR; at 30 and 45 min from the pneumoperitoneum. Patients in group L showed statistically significant lower mean values of the MBP; 60 min from the pneumoperitoneum, after release of pneumoperitoneum and in the PACU. Patients of both groups showed comparable mean values of the HR after 60 min from the pneumoperitoneum, after release of the pneumoperitoneum and in the PACU. No patient in either groups developed post-operative respiratory depression in the PACU. Patients in group L showed statistically significant higher median sedation score, which was reflected on statistically but not clinically significant less Modified Aldrete score in patients of group L.

Conclusions

In morbid obese patients, the intra-operative IV lidocaine infusion offered post-operative analgesia in the PACU, on the expense of a higher sedation score, which didn’t affect the Modified Aldrete score clinically, with attenuation of the stress response to endotracheal intubation and extubation.

Trial registrations

FMASU R16/2021. Registered 1st February 2021, with Clinical Trials Registry (NCT05150756) on 10/08/2021.

Effect of perioperative lignocaine infusion on postoperative pain relief for laparoscopic intraperitoneal onlay mesh repair: A randomized controlled study

INTRODUCTION

The focus on enhanced recovery after surgery (ERAS) and opioid-free anesthesia has renewed interest in use of lignocaine. We evaluated postoperative pain relief following intravenous (IV) lignocaine administration in patients undergoing laparoscopic intraperitoneal onlay mesh repair (IPOM).

METHODS

Seventy patients were randomized into two groups. Group L patients were administered IV lignocaine infusion (1.5 mg/kg) at induction of anesthesia followed by infusion (1.5 mg/kg/h), until 1 hour in the post-anesthesia care unit (PACU). Group P patients received equal volumes of normal saline IV infusion. We recorded hemodynamics, perioperative analgesic consumption, postoperative visual analog scores (VAS), incidence of postoperative nausea and vomiting (PONV), bowel function, patient satisfaction and length of hospital stay (LOS).

RESULTS

The hemodynamics in both groups were maintained. Group L had lower VAS scores as compared to Group P (P < .05). Intraoperative fentanyl consumption in Group L was significantly less than Group P (P = .029). Group L patients scored lower on the Likert scale in comparison to the patients of Group P at 0 hour (P = .013). Recovery of bowel function as assessed by time to pass first flatus was significantly shortened by IV lignocaine (P = .001). The perioperative administration of IV lignocaine resulted in decreased postoperative analgesic requirement and greater patient satisfaction scores.

CONCLUSIONS

Perioperative IV lignocaine infusion provided good pain relief, hemodynamic stability and decreased perioperative analgesic consumption. PONV incidence decreased along with an early return of bowel function, reduced LOS and improved patient satisfaction in patients undergoing laparoscopic IPOM surgery.

Outcomes After Orthopedic Trauma Surgery - What is the Role of the Anesthesia Choice?

The body of literature concerning the influence of anesthetic type on many perioperative outcomes has grown considerably in recent years. Most studies have suggested that particularly in orthopedic patients, regional anesthesia may be associated with improved perioperative outcomes. Orthopedic trauma presents itself as a field that might benefit from increased utilization of regional techniques with the goal to improve outcomes. This narrative review concludes that, indeed, regional anesthesia seems to provide benefits for morbidity, pain control, and improved return to function in hip fracture, rib fracture, and isolated extremity fracture patients.

Comparison of Supraclavicular Regional Nerve Block Versus Infraclavicular Regional Nerve Block in Distal Radial Open Reduction and Internal Fixation: A Retrospective Case Series

Background

The management of pain in patients undergoing open reduction and internal fixation (ORIF) of distal radius fractures (DRFs) remains an area of debate for anesthesiologists due to a variety of block options and no definitive superior technique among these modalities. In this retrospective case series, we compare the efficacy of supraclavicular versus infraclavicular regional nerve blocks for surgical patients undergoing distal radial ORIF operations to determine if one approach was superior.

Methodology

This retrospective case series included patients undergoing ORIF of a DRF at a tertiary academic medical center between April 28, 2016, and August 23, 2021. In total, 54 patients undergoing ORIF of a DRF provided written consent for the nerve block(s) on the day of surgery. Of these 54 patients, 54 (100%) underwent primary procedures. Of the 54 primary ORIF patients, 28 (52%) received the supraclavicular block, while 26 (48%) received the infraclavicular nerve block.

Results

The infraclavicular and supraclavicular groups did not significantly differ regarding age, gender, American Society of Anesthesiologists, weight, or body mass index. The primary (intraoperative opioid use) and secondary (postoperative opioid use, postoperative nausea and vomiting in the post-anesthetic care unit, highest and average pain scores, and time to discharge) outcomes data were included in the study. The infraclavicular and supraclavicular groups did not significantly differ in any of the assessed outcomes except for time to discharge.

Conclusions

The supraclavicular block approach for distal radius ORIF offers an effective and non-inferior alternative to the infraclavicular block approach concerning effective analgesia and safety.

Regional Anesthesia for Athletes Undergoing Upper Extremity Procedures: Techniques and Considerations

Upper extremity injuries are frequent in athletes which may require surgeries. Regional anesthesia for postoperative analgesia is important to aid recovery, and peripheral nerve blocks for surgical anesthesia enable surgeries to be performed without general anesthetics and their associated adverse effects. The relevant nerve block approaches to anesthetize the brachial plexus for elbow, wrist and hand surgeries are discussed in this article. There is very limited margin for error when performing nerve blocks and multimodal monitoring approach to reduce harm are outlined. Lastly, the importance of obtaining informed consent prior to nerve block procedures should not be overlooked.

Erector spinae plane block vs. peri-articular injection for pain control after arthroscopic shoulder surgery: a randomised controlled trial

Interscalene brachial plexus block is the standard regional analgesic technique for shoulder surgery. Given its adverse effects, alternative techniques have been explored. Reports suggest that the erector spinae plane block may potentially provide effective analgesia following shoulder surgery. However, its analgesic efficacy for shoulder surgery compared with placebo or local anaesthetic infiltration has never been established. We conducted a randomised controlled trial to compare the analgesic efficacy of pre-operative T2 erector spinae plane block with peri-articular infiltration at the end of surgery. Sixty-two patients undergoing arthroscopic shoulder repair were randomly assigned to receive active erector spinae plane block with saline peri-articular injection (n = 31) or active peri-articular injection with saline erector spinae plane block (n = 31) in a blinded double-dummy design. Primary outcome was resting pain score in recovery. Secondary outcomes included pain scores with movement; opioid use; patient satisfaction; adverse effects in hospital; and outcomes at 24 h and 1 month. There was no difference in pain scores in recovery, with a median difference (95%CI) of 0.6 (-1.9-3.1), p = 0.65. Median postoperative oral morphine equivalent utilisation was significantly higher in the erector spinae plane group (21 mg vs. 12 mg; p = 0.028). Itching was observed in 10% of patients who received erector spinae plane block and there was no difference in the incidence of significant nausea and vomiting. Patient satisfaction scores, and pain scores and opioid use at 24 h were similar. At 1 month, six (peri-articular injection) and eight (erector spinae plane block) patients reported persistent pain. Erector spinae plane block was not superior to peri-articular injection for arthroscopic shoulder surgery.

Perioperative Pain Management Issues Unique to Older Adults Undergoing Surgery: A Narrative Review

INTRODUCTION

The older population is growing and with this growth there is a parallel rise in the operations performed on this vulnerable group. The perioperative pain management strategy for older adults is unique and requires a team-based approach for provision of high-quality surgical care.

METHODS

Literature search was performed using PubMed in addition to review of relevant protocols and guidelines from geriatric, surgical, and anesthesia societies. Systematic reviews and meta-analyses, randomized trials, observational studies, and society guidelines were summarized in this review.

MANAGEMENT

The optimal approach to a pain management strategy for older adults undergoing surgery involves addressing all phases of perioperative care. For example, preoperative assessment of a patient's cognitive function and presence of chronic pain may impact the pain management plan. Consideration should be also given to intraoperative strategies to improve pain control and minimize both the dose and side effects from opioids (e.g. regional anesthetic techniques). Postoperative pain control (e.g. under or over treatment of pain) may impact the development of elderly-specific complications such as postoperative delirium and functional decline. Finally, pain management does not stop after the older adult patient leaves the hospital. Both discharge planning and post-operative clinic follow-up provide important opportunities for collaboration and intervention.

CONCLUSIONS

An opioid-sparing pain management strategy for older adults can be accomplished with a comprehensive and collaborative interdisciplinary strategy addressing all phases of perioperative care.

How to Minimize the Pain of Local Anesthetic Injection for Wide Awake Surgery

After reading this article, the participant should be able to (1) almost painlessly inject tumescent local anesthesia to anesthetize small or large parts of the body, (2) improve surgical safety by eliminating the need for unnecessary sedation in patients with multiple medical comorbidities, and (3) convert many limb and face operations to wide awake surgery. We recommend the following 13 tips to minimize the pain of local anesthesia injection: (1) buffer local anesthetic with sodium bicarbonate; (2) use smaller 27- or 30-gauge needles; (3) immobilize the syringe with two hands and have your thumb ready on the plunger before inserting the needle; (4) use more than one type of sensory noise when inserting needles into the skin; (5) try to insert the needle at 90 degrees; (6) do not inject in the dermis, but in the fat just below it; (7) inject at least 2 ml slowly just under the dermis before moving the needle at all and inject all local anesthetic slowly when you start to advance the needle; (8) never advance sharp needle tips anywhere that is not yet numb; (9) always inject from proximal to distal relative to nerves; (10) use blunt-tipped cannulas when tumescing large areas; (11) only reinsert needles into skin that is already numb when injecting large areas; (12) always ask patients to tell you every time they feel pain during the whole injection process so that you can score yourself and improve with each injection; (13) always inject too much volume instead of not enough volume to eliminate surgery pain and the need for "top ups."

Comparison of Regional Anesthesia Timing on Pain, Opioid Use, and Postanesthesia Care Unit Length of Stay in Patients Undergoing Open Reduction and Internal Fixation of Ankle Fractures

Regional nerve blocks are an effective method of managing acute pain associated with surgery. The relative benefit of preoperative versus postoperative peripheral nerve blocks is not entirely clear. The primary aim of this study was to determine differences in pain scores in patients undergoing preoperative block versus postoperative block versus no block. We hypothesized that patients receiving preoperative blocks would have reduced pain scores and decreased opioid use in the immediate postoperative period. We conducted a retrospective cohort analysis of 302 consecutive patients undergoing unilateral open reduction and internal fixation of ankle fracture under general anesthesia. We identified 3 groups: preoperative block, postoperative block, or no block. Data obtained from our electronic medical records included demographic information, postanesthesia care unit length of stay, pain scores obtained preoperatively, upon arrival to the postanesthesia care unit, and upon discharge from the postanesthesia care unit as well as intraoperative and postanesthesia care unit opioid utilization. Patients receiving preoperative block had significantly lower pain scores, less intraoperative or postanesthesia care unit opioid use, and shorter postanesthesia care unit dwell time compared with patients receiving postoperative block or no block. Preoperative popliteal sciatic and adductor canal blocks in patients undergoing ankle fracture surgery appears to be more effective than either postoperative block or no block.

Mechanisms, diagnosis, prevention and management of perioperative opioid-induced hyperalgesia

Opioid-induced hyperalgesia (OIH) occurs when opioids paradoxically enhance the pain they are prescribed to ameliorate. To address a lack of perioperative awareness, we present an educational review of clinically relevant aspects of the disorder. Although the mechanisms of OIH are thought to primarily involve medullary descending pathways, it is likely multifactorial with several relevant therapeutic targets. We provide a suggested clinical definition and directions for clinical differentiation of OIH from other diagnoses, as this may be confusing but is germane to appropriate management. Finally, we discuss prevention including patient education and analgesic management choices. As prevention may serve as the best treatment, patient risk factors, opioid mitigation, and both pharmacologic and non-pharmacologic strategies are discussed.

Towards an improved pain assessment in castrated horses using facial expressions (HGS) and circulating miRNAs

BACKGROUND

Pain in horses is an emergent welfare concern, and its assessment represents a challenge for equine clinicians. This study aimed at improving pain assessment in horses through a convergent validation of existing tools: we investigated whether an effective analgesic treatment influences the horse grimace scale (HGS) and the concentration of specific circulating microRNAs (miRNAs).

METHODS

Eleven stallions underwent routine surgical castration under general anaesthesia. They were divided into two analgesic treatment groups: castration with the administration of preoperative flunixin and castration with preoperative flunixin plus a local injection of mepivacaine into the spermatic cords. HGS and levels of seven circulating miRNAs were evaluated pre-, 8 and 20 hours post-procedure.

RESULTS

Compared to pre-castration, HGS, miR-126-5p, miR-145 and miR-let7e increased significantly in horses receiving flunixin at 8 hours post-castration (Friedman test, p < 0.05). Both behavioural and molecular changes occurred in horses receiving flunixin only, confirming that the addition of local mepivacaine is an effective analgesic treatment.

CONCLUSIONS

Combining the use of HGS and circulating miRNAs, particularly miR-145, could be meaningful to monitor acute pain conditions in horses. Our results further validate the HGS as a method to assess acute pain in horses and point out miR-145 as a promising biomarker to identify pain.

Minimum Effective Analgesic Concentration of Ropivacaine in Saphenous Block Guided by Ultrasound for Knee Arthroscopic Meniscectomy: Randomized, Double-Blind Study

Background

After knee surgery, analgesia should be effective for mobilization and discharge.

Aim of the Study

The primary objective of this study was to achieve the lowest effective analgesic concentration (MEC50 and MEC90) of ropivacaine for saphenous nerve block in arthroscopic meniscectomy. The secondary objective was to determine whether the block causes muscle weakness in the postoperative period.

Methods

The study was randomized, comparative, and double-blind. Fifty-one patients between 18 and 65 years old of both sexes, ASA I or II, who underwent knee arthroscopic meniscectomy at São Domingos Hospital were included. Patients underwent saphenous nerve block with 10 mL of ropivacaine administered by using the up-and-down method. The ropivacaine concentration was determined based on the previous patient’s response (a biased-coin up-down design sequential method). If a patient had a negative response, the concentration of ropivacaine was increased by 0.05% in the next patient; if the response was positive, the next patient was randomized to be administered the same concentration of ropivacaine or a 0.05% lower concentration. Successful block was defined as pain <4 during 6 h. Patients underwent general anesthesia with 30 µg/kg alfentanil and propofol and maintenance with propofol, and, if necessary, remifentanil was administered. Postoperative analgesia was complemented with dipyrone, and if necessary, tramadol (100 mg) could be used. The following parameters were assessed: the success of the block; pain intensity after 2, 4, and 6 h; the consumption of remifentanil; time to the first analgesic supplementation; percent of patients who needed analgesics during 6h; and muscle strength.

Results

The MEC50 of ropivacaine was 0.36%, and the MEC90 was 0.477%. The block was successful in 45 patients.

Conclusion

Saphenous block with 10 mL of 0.36% ropivacaine provides adequate analgesia for outpatient meniscectomy.

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.

Can local anesthesia with ropivacaine provide postoperative analgesia in extraction of impacted mandibular third molars? A randomized clinical trial

OBJECTIVE

The aim of this study was to compare the local anesthesia efficacy of ropivacaine 0.75% compared to lidocaine 2% with 1:100,000 epinephrine for postoperative analgesia following extraction of impacted mandibular third molars.

STUDY DESIGN

In this randomized, double-blind crossover clinical trial, 30 participants underwent surgical removal of bilateral impacted mandibular third molars under local anesthesia using ropivacaine 0.75% or lidocaine 2% with 1:100,000 epinephrine. The pain was recorded on a visual analog scale at 4, 8, 12, 24, and 48 h postoperatively. The use of analgesics and the presence of adverse effects were recorded.

RESULTS

The duration of soft tissue anesthesia in the ropivacaine group was significantly longer than that in the lidocaine group. The lidocaine group recorded significantly higher visual analog scale scores at all postoperative time intervals, except in the final 48-h period. Analgesic use was higher in the lidocaine group. Rescue medication was used by 2 patients in each group (6.7%). Significantly more postoperative bleeding was seen in the ropivacaine group.

CONCLUSION

Ropivacaine 0.75% injection before the surgical procedure may be associated with preventive analgesia for extraction of impacted mandibular third molars.

The use of intravenous lidocaine for postoperative pain and recovery: international consensus statement on efficacy and safety

Intravenous lidocaine is used widely for its effect on postoperative pain and recovery but it can be, and has been, fatal when used inappropriately and incorrectly. The risk-benefit ratio of i.v. lidocaine varies with type of surgery and with patient factors such as comorbidity (including pre-existing chronic pain). This consensus statement aims to address three questions. First, does i.v. lidocaine effectively reduce postoperative pain and facilitate recovery? Second, is i.v. lidocaine safe? Third, does the fact that i.v. lidocaine is not licensed for this indication affect its use? We suggest that i.v. lidocaine should be regarded as a 'high-risk' medicine. Individual anaesthetists may feel that, in selected patients, i.v. lidocaine may be beneficial as part of a multimodal peri-operative pain management strategy. This approach should be approved by hospital medication governance systems, and the individual clinical decision should be made with properly informed consent from the patient concerned. If i.v. lidocaine is used, we recommend an initial dose of no more than 1.5 mg.kg^-1 , calculated using the patient's ideal body weight and given as an infusion over 10 min. Thereafter, an infusion of no more than 1.5 mg.kg^-1 .h^-1 for no longer than 24 h is recommended, subject to review and re-assessment. Intravenous lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions. This includes not starting i.v. lidocaine within 4 h after any nerve block, and not performing any nerve block until 4 h after discontinuing an i.v. lidocaine infusion.

Optimizing Perioperative Use of Opioids: A Multimodal Approach

Purpose of Review

The main purpose of this article is to review recent literature regarding multimodal analgesia medications, citing their recommended doses, efficacy, and side effects. The second part of this report will provide a description of drugs in different stages of development which have novel mechanisms with less side effects such as tolerance and addiction.

Recent Findings

Multimodal analgesia is a technique that facilitates perioperative pain management by employing two or more systemic analgesics along with regional anesthesia, when possible. Even though opioids and non-opioid analgesics remain the most common medication used for acute pain management after surgery, they have many undesirable side effects including the potential for misuse. Newer analgesics including peripheral acting opioids, nitric oxide inhibitors, calcitonin gene-related peptide receptor antagonists, interleukin-6 receptor antagonists and gene therapy are under intensive investigation.

Summary

A patient's first exposure to opioids is often in the perioperative setting, a vulnerable time when multimodal therapy can play a large role in decreasing opioid exposure. Additionally, the current shift towards faster recovery times, fewer post-operative complications and improved cost-effectiveness during the perioperative period has made multimodal analgesia a central pillar of Enhanced Recovery After Surgery (ERAS) protocols.

Transmuscular quadratus lumborum block for percutaneous nephrolithotomy: Study protocol for a dose-finding trial

BACKGROUND

The objective of this trial is to optimize the transmuscular quadratus lumborum (TQL) block, by investigating the minimal effective volume (MEV₉₀ ) of ropivacaine 0.75% for single-shot TQL block in percutaneous nephrolithotomy (PNL) patients.

METHODS

This double-blind, randomized and controlled dose-finding trial is based on a biased coin up-and-down sequential design, where the volume of local anaesthetic administered to each patient depends on the response from the previous one. Investigating the TQL block, the first patient recruited receives 20 ml ropivacaine 0.75% preoperatively. In case of block failure, the next patient will receive the same volume with an increment of 2 ml. Given a successful block for the first patient, the next patient will be randomized to either a lower volume (previous volume with a reduction of 2 ml), or the same volume as the previous patient. The respective probabilities being b = 0.11 for a reduced volume and 1-b = 0.89 for the same volume. Block success is defined as patient reported pain score numeric rated scale (NRS) ≤3 (0-10/10) 30 minutes after arrival in the post anaesthesia care unit (PACU). The NRS pain score is our primary and only outcome for block success. A minimum of 25 eligible patients are needed to achieve precise estimation of MEV₉₀ with narrow 95% confidence intervals derived by bootstrapping.

DISCUSSION

Recruiting will begin June 2020 and is expected to finish November 2020. Data analysis will be performed at interims during and after the study. Results will be published in an international peer-reviewed medical journal.

Intraoperative lidocaine infusion and 24-hour postoperative opioid consumption in obese patients undergoing laparoscopic bariatric surgery

BACKGROUND

Bariatric surgery is the most effective long-term treatment for obesity. Opioid-sparing anesthesia and multimodal analgesia such as lidocaine infusion have been recommended in these patients to reduce opioid-related complications. However, evidence supporting its use for bariatric surgery population is limited.

OBJECTIVE

To investigate whether intraoperative lidocaine infusion is associated with decreasing opioid consumption in laparoscopic bariatric surgery.

SETTING

A university hospital, California, USA.

METHODS

In this retrospective cohort study, outcomes among consecutive obese patients undergoing laparoscopic bariatric surgery between January 2016 to December 2018 were evaluated to determine the impact of adjunctive intraoperative lidocaine infusion on 24-hour postoperative opioid consumption. Secondary outcomes, including opioid consumption during hospitalization, length of stay, and postoperative complications were determined. Post hoc analyses were performed exploring possible dose effects and drug-drug interactions. Univariable and multivariable analyses were performed to identify factors associated with opioid consumption.

RESULTS

Among 345 patients, 54 (15.7%) received intraoperative lidocaine infusion (L+) whereas 291 (84.3%) did not receive intraoperative lidocaine infusion (L-). Both L+ and L- groups shared similar demographic characteristics. The 24-hour postoperative opioid consumption was 17.6% lower in L+ (95% confidence interval -28.4 to -5.2, P = .007), but nonsignificantly lower in the multivariate model (12.8%, 95% confidence interval -24.4 to .5, P = .06). Opioid consumption during hospitalization, length of stay, and other clinically significant outcomes did not differ. However, subgroup analysis restricted to opioid-naïve patients indicated significantly reduced opioid consumption in the L+ group. Post hoc analysis suggested interaction between lidocaine and ketamine in decreasing 24-hour postoperative opioid consumption.

CONCLUSIONS

Intraoperative lidocaine infusion was not significantly associated with decreasing 24-hour postoperative opioid consumption in obese patients undergoing laparoscopic bariatric surgery.

Article Commentary: Defining New Directions for More Effective Management of Surgical Pain in the United States: Highlights of the Inaugural Surgical Pain Congress™

Despite advances in pharmacologic options for the management of surgical pain, there appears to have been little or no overall improvement over the last two decades in the level of pain experienced by patients. The importance of adequate and effective surgical pain management, however, is clear, because inadequate pain control 1) has a wide range of undesirable physiologic and immunologic effects; 2) is associated with poor surgical outcomes; 3) has increased probability of readmission; and 4) adversely affects the overall cost of care as well as patient satisfaction. There is a clear unmet need for a national surgical pain management consensus task force to raise awareness and develop best practice guidelines for improving surgical pain management, patient safety, patient satisfaction, rapid postsurgical recovery, and health economic outcomes. To comprehensively address this need, the multidisciplinary Surgical Pain Congress™ has been established. The inaugural meeting of this Congress (March 8 to 10, 2013, Celebration, Florida) evaluated the current surgical pain management paradigm and identified key components of best practices.

Infraclavicular nerve block reduces postoperative pain after distal radial fracture fixation: a randomized controlled trial

Background

It is unclear whether regional anesthesia with infraclavicular nerve block or general anesthesia provides better postoperative analgesia after distal radial fracture fixation, especially when combined with regular postoperative analgesic medications. The aim of this study was to compare the postoperative analgesic effects of regional versus general anesthesia.

Methods

In this prospective, observer blinded, randomized controlled trial, 52 patients undergoing distal radial fracture fixation received either general anesthesia (n = 26) or regional anesthesia (infraclavicular nerve block, n = 26). Numerical rating scale pain scores, analgesic consumption, patient satisfaction, adverse effects, upper limb functional scores (Patient-Rated Wrist Evaluation, QuickDASH), health related quality of life (SF12v2), and psychological status were evaluated after surgery.

Result

Regional anesthesia was associated with significantly lower pain scores both at rest and with movement on arrival to the post-anesthetic care unit; and at 1, 2, 24 and 48 h after surgery (p ≤ 0.001 at rest and with movement). Morphine consumption in the post-anesthetic care unit was significantly lower in the regional anesthesia group (p<0.001). There were no differences in oral analgesic consumption. Regional anesthesia was associated with lower incidences of nausea (p = 0.004), and vomiting (p = 0.050). Patient satisfaction was higher in the regional anesthesia group (p = 0.003). There were no long-term differences in pain scores and other patient outcomes.

Conclusion

Regional anesthesia with ultrasound guided infraclavicular nerve block was associated with better acute pain relief after distal radial fracture fixation, and may be preferred over general anesthesia.

Trial registration

Before subject enrollment, the study was registered at ClinicalTrials.gov (NCT03048214) on 9th February 2017.

The effects of intravenous lidocaine on wound pain and gastrointestinal function recovery after laparoscopic colorectal surgery

To evaluate the efficacy of intravenous lidocaine in relieving postoperative pain and promoting rehabilitation in laparoscopic colorectal surgery, we conducted this meta-analysis. The systematic search strategy was performed on PubMed, EMBASE, Chinese databases, and Cochrane Library before September 2019. As a result, 10 randomised clinical trials were included in this meta-analysis (n = 527 patients). Intravenous lidocaine significantly reduced pain scores at 2, 4, 12, 24, and 48 hours on movement and 2, 4, and 12 hours on resting-state and reduced opioid requirement in first 24 hours postoperatively (weighted mean difference [WMD] = -5.02 [-9.34, -0.70]; P = .02). It also decreased the first flatus time (WMD: -10.15 [-11.20, -9.10]; P < .00001), first defecation time (WMD: -10.27 [-17.62, -2.92]; P = .006), length of hospital stay (WMD: -1.05 [-1.89, -0.21]; P = .01), and reduced the incidence of postoperative nausea and vomiting (risk ratio: 0.53 [0.30, 0.93]; P = .03) when compared with control group. However, it had no effect on pain scores at 24 and 48 hours at rest, the normal dietary time, and the level of serum C-reactive protein. In summary, perioperative intravenous lidocaine could alleviate acute pain, reduce postoperative analgesic requirements, and accelerate recovery of gastrointestinal function in patients undergoing laparoscopic colorectal surgery.

Effect of intraoperative paravertebral or intravenous lidocaine versus control during lung resection surgery on postoperative complications: A randomized controlled trial

BACKGROUND

Use of minimally invasive surgical techniques for lung resection surgery (LRS), such as video-assisted thoracoscopy (VATS), has increased in recent years. However, there is little information about the best anesthetic technique in this context. This surgical approach is associated with a lower intensity of postoperative pain, and its use has been proposed in programs for enhanced recovery after surgery (ERAS). This study compares the severity of postoperative complications in patients undergoing LRS who have received lidocaine intraoperatively either intravenously or via paravertebral administration versus saline.

METHODS/DESIGN

We will conduct a single-center randomized controlled trial involving 153 patients undergoing LRS through a thoracoscopic approach. The patients will be randomly assigned to one of the following study groups: intravenous lidocaine with more paravertebral thoracic (PVT) saline, PVT lidocaine with more intravenous saline, or intravenous remifentanil with more PVT saline. The primary outcome will be the comparison of the postoperative course through Clavien-Dindo classification. Furthermore, we will compare the perioperative pulmonary and systemic inflammatory response by monitoring biomarkers in the bronchoalveolar lavage fluid and blood, as well as postoperative analgesic consumption between the three groups of patients. We will use an ANOVA to compare quantitative variables and a chi-squared test to compare qualitative variables.

DISCUSSION

The development of less invasive surgical techniques means that anesthesiologists must adapt their perioperative management protocols and look for anesthetic techniques that provide good analgesic quality and allow rapid rehabilitation of the patient, as proposed in the ERAS protocols. The administration of a continuous infusion of intravenous lidocaine has proven to be useful and safe for the management of other types of surgery, as demonstrated in colorectal cancer. We want to know whether the continuous administration of lidocaine by a paravertebral route can be substituted with the intravenous administration of this local anesthetic in a safe and effective way while avoiding the risks inherent in the use of regional anesthetic techniques. In this way, this technique could be used in a safe and effective way in ERAS programs for pulmonary resection.

TRIAL REGISTRATION

EudraCT, 2016-004271-52; ClinicalTrials.gov, NCT03905837 . Protocol number IGGFGG-2016 version 4.0, 27th April 2017.

Continuous Intravenous Lidocaine as an Effective Pain Adjunct for Opioid-Induced Bowel Dysfunction: A Case Report

This case study describes a patient with suspected opioid-induced bowel dysfunction who had improved pain control when treated with intravenous (IV) lidocaine. An 80-year-old man with failed back surgery syndrome managed with an intrathecal (IT) pump presented with protracted abdominal pain. The acute pain service initiated a lidocaine infusion at 1 mg·min, and the patient reported significant pain relief. The patient experienced refractory abdominal pain with 3 attempts to wean the lidocaine infusion. Eventually, a successful transitional regimen was achieved with methylnaltrexone and transdermal lidocaine patches. Lidocaine infusions may be an effective and underutilized multimodal adjunct for nonsurgical pain conditions.

The intraoperative use of non-opioid adjuvant analgesic agents: a survey of anaesthetists in Australia and New Zealand

BACKGROUND

Opioids have long been the mainstay of drugs used for intra-operative analgesia. Due to their well-known short and long term side effects, the use of non-opioid analgesics has often been encouraged to decrease the dose of opioid required and minimise these side effects. The trends in using non-opioid adjuvants among Australian Anaesthetists have not been examined before. This study has attempted to determine the use of non-opioid analgesics as part of an opioid sparing practice among anaesthetists across Australia and New Zealand.

METHODS

A survey was distributed to 985 anaesthetists in Australia and New Zealand. The questions focused on frequency of use of different adjuvants and any reasons for not using individual agents. The agents surveyed were paracetamol, dexamethasone, non-steroidal anti-inflammatory agents (NSAIDs), tramadol, ketamine, anticonvulsants, intravenous lidocaine, systemic alpha 2 agonists, magnesium sulphate, and beta blockers. Descriptive statistics were used and data are expressed as a percentage of response for each drug.

RESULTS

The response rate was 33.4%. Paracetamol was the most frequently used; with 72% of the respondents describing frequent usage (defined as usage above 70% of the time); followed by parecoxib (42% reported frequent usage) and dexamethasone (35% reported frequent usage). Other adjuvants were used much less commonly, with anaesthetists reporting their frequent usage at less than 10%. The majority of respondents suggested that they would never consider dexmedetomidine, magnesium, esmolol, pregabalin or gabapentin. Perceived disincentives for the use of analgesic adjuvants varied. The main concerns were side effects, lack of evidence for benefit, and anaesthetists' experience. The latter two were the major factors for magnesium, dexmedetomidine and esmolol.

CONCLUSION

The uptake of tramadol, lidocaine and magnesium amongst respondents from anaesthetists in Australia and New Zealand was poor. Gabapentin, pregabalin, dexmedetomidine and esmolol use was relatively rare. Most anaesthetists need substantial evidence before introducing a non-opioid adjuvant into their routine practice. Future trials should focus on assessing the opioid sparing benefits and relative risk of using individual non-opioid adjuvants in the perioperative period for specific procedures and patient populations.

Acute Pain in Older Adults: Recommendations for Assessment and Treatment

The management of acute pain in older adults (age 65 or greater) requires special attention due to various physiologic, cognitive, functional, and social issues that may change with aging. Especially in the postoperative setting, there are significant complications that can occur if pain is not treated adequately for elderly patients. In this article, the authors describe these changes in detail and discuss how pain should be assessed appropriately in older patients. In addition, the authors detail the unique risks and benefits of several mainstream analgesic medications as well as interventional treatments for elderly patients. The authors' goal is to provide recommendations for health care providers on appropriately recognizing and treating pain in a safe, effective manner for aging patients.

Sucrose Acetate Isobutyrate as an In situ Forming Implant for Sustained Release of Local Anesthetics

OBJECTIVE

In this study, an injectable Sucrose Acetate Isobutyrate (SAIB) drug delivery system (SADS) was designed and fabricated for the sustained release of Ropivacaine (RP) to prolong the duration of local anesthesia.

METHODS

By mixing SAIB, RP, and N-methyl-2-pyrrolidone, the SADS was prepared in a sol state with low viscosity before injection. After subcutaneous injection, the pre-gel solution underwent gelation in situ to form a drug-released depot.

RESULT

The in vitro release profiles and in vivo pharmacokinetic analysis indicated that RP-SADS had suitable controlled release properties. Particularly, the RP-SADS significantly reduced the initial burst release after subcutaneous injection in rats.

CONCLUSION

In a pharmacodynamic analysis of rats, the duration of nerve blockade was prolonged by over 3-fold for the RP-SADS formulation compared to RP solution. Additionally, RP-SADS showed good biocompatibility in vitro and in vivo. Thus, the SADS-based depot technology is a safe drug delivery strategy for the sustained release of local anesthetics with long-term analgesia effects.

Lipid-based carriers for the delivery of local anesthetics

INTRODUCTION

There is a clinical need for pharmaceutical dosage forms devised to prolong the acting time of local anesthetic (LA) agents or to reduce their toxicity. Encapsulation of LA in drug delivery systems (DDSs) can provide long-term anesthesia for inpatients (e.g. in immediate postsurgical pain control, avoiding the side effects from systemic analgesia) and diminished systemic toxicity for outpatients (in ambulatory/dentistry procedures). The lipid-based formulations described here, such as liposomes, microemulsions, and lipid nanoparticles, have provided several nanotechnological advances and therapeutic alternatives despite some inherent limitations associated with the fabrication processes, costs, and preclinical evaluation models.

AREAS COVERED

A description of the currently promising lipid-based carriers, including liposomes, microemulsions, and nanostructured lipid carriers, followed by a systematic review of the existing lipid-based formulations proposed for LA. Trends in the research of these LA-in-DDS are then exposed, from the point of view of administration route and alternatives for non-traditionally administered LA molecules.

EXPERT OPINION

Considering the current state and potential future developments in the field, we discuss the reasons for why dozens of formulations published every year fail to reach clinical trials; only one lipid-based formulation for the delivery of local anesthetic (Exparel®) has been approved so far.

Intra-Articular Morphine versus Dexmedetomedine for Knee Arthroscopy under Local Anesthesia

Background:

Knee arthroscopy has both diagnostic and therapeutic applications which can be performed under general, regional, or local anesthesia. Morphine is used as an additive to local anesthetics. Dexmedetomedine, the highly selective alpha-2 (α2)-adrenoceptor agonist with the sedative and analgesic effect can be used also to augment local anesthetic effect.

Patients and Methods:

Sixty patients submitted for elective knee arthroscopy whose age between 25 and 45 years, of either sex, the American society of anethesiologists physical status Classes I and II at a university hospital were enrolled in this study. Patients were classified into two groups. Morphine Group (M) (n = 30): Patients received 20 ml of 0.5% bupivacaine plus 5 ml of 0.2% lidocaine with epinephrine 1:200,000 plus 1 mg morphine. Dexmedetomedine Group (D) (n = 30): Patients received 20 ml of 0.5% bupivacaine plus 5 ml of 0.2% lidocaine with epinephrine 1:200,000 plus 1 μg/kg dexmedetomedine.

Results:

Demographic data of patients showed no significant difference among the studied groups. Heart rate (HR) was significantly lower in (D) Group compared to that of (M) Group 5 min from the start of procedure to immediately postoperatively. Moreover, (D) Group showed a significant decrease in HR 10 min up to 35 min intraoperatively compared to the basal value. Furthermore, mean arterial blood pressure (MBP) was significantly lower in (D) Group compared to that of (M) Group 15 min from the start of surgery up to 1 h postoperatively. Furthermore, (D) Group showed a significant decrease in MBP 15 min intraoperative up to 2 h postoperatively compared to the basal value. While there was no significant difference in (visual analogue score [VAS], onset and total consumption of ketorolac, surgeon and patients’ satisfaction, side effects in (D) Group compared to (M) Group, respectively.

Conclusion:

Addition of either morphine or dexmedetomidine to bupivacaine intraarticularly improved both intraoperative anesthesia and postoperative analgesia with minimal side effects or complications in knee arthroscopy, with superiority of dexmedetomidine compared to morphine on hemodynamic stability.

Effect of magnesium and lignocaine on post-craniotomy pain: A comparative, randomized, double blind, placebo-controlled study

Background:

Lignocaine and Magnesium have an analgesic action and reduce perioperative opioid requirements. We carried out this study to evaluate the effect of magnesium and lignocaine on postoperative pain as assessed using the visual analog scale (VAS) and fentanyl consumption. We also measured S-100 B levels and noted the side effect of drugs if any.

Materials and Methods:

In this prospective preliminary study, 45 patients undergoing supratentorial craniotomy for tumor surgery were randomized to receive either lignocaine (group I-1.5 mg/kg bolus followed by 2 mg/kg/h infusion), saline (Group II) or magnesium (group III: bolus of 50 mg/kg followed by 25 mg/kg/hr) intraoperatively. The amount of fentanyl required, VAS over first 24 hours and any side effects were noted. S100 B levels were also measured to assess brain protective effect of these drugs, if any. Appropriate statistical tests were applied for analysis of data and a P value < 0.05 was considered statistically significant.

Results:

None of the patient experienced any adverse hemodynamic effect intraoperatively secondary to the study drugs. The amount of intraoperative fentanyl consumption was comparable among the three groups. The mean VAS score was significantly less in group I and III [Group I (15.3 ± 6.0), Group II (24.8 ± 6.7), Group III (17.9 ± 7.6); (P < 0.01)]. The fentanyl consumed in first 24 hours was significantly less in those patients who received lignocaine and magnesium [Group I (204.4 ± 136.4), Group II (383 ± 168.2), Group III (194 ± 148.9); (P = 0.01)]. S100 value did not differ in the lignocaine and the saline group during the perioperative period. However, a significant decline was noted in the levels of S100 B in the magnesium group.

Conclusion:

Intraoperative infusion of lignocaine and magnesium results in lower VAS score and decreases the postoperative opioid requirement in patients undergoing craniotomy for excision of supratentorial tumors.

Fascia-iliaca compartment block vs intra-articular hip injection for preoperative pain management in intracapsular hip fractures: A blind, randomized, controlled trial

BACKGROUND

The aim of this study was to compare the fascia-iliaca compartment block and the intra-articular hip injection in terms of pain management and the need for additional systemic analgesia in the preoperative phase of intracapsular hip fractures.

METHODS

Patients >65 years old with an intracapsular hip fracture were randomized in this prospective, blind, controlled, parallel trial in a Level-I trauma center. Patients were randomly assigned to receive either the fascia-iliaca compartment block (cohort FICB) or the intra-articular hip injection (cohort IAHI) upon admission to the emergency department. The primary outcome was pain relief at 20 min, 12 h, 24 h and 48 h after the regional anesthesia, both at rest and during internal rotation of the fractured limb. The Numeric Rating Scale was used. Residual pain was managed with the same protocol in all patients. Additional analgesic drug administration during the 48 h from admission was recorded.

RESULTS

A total of 120 patients with comparable baseline characteristics were analyzed in this study: the FICB group consisted of 70 subjects, while the IAHI group consisted of 50 subjects. Pain was significantly lower in the IAHI group during movement of the fractured limb at 20 min (p < 0.05), 12 h (p < 0.05), 24 h (p < 0.05) and 48 h (p < 0.05). In the FICB cohort 72.9% of patients needed to take oxycodone, in contrast to 28.6% of the IAHI cohort (p < 0.05). In the FICB cohort 14.09 ± 11.57 mg of oxycodone was administered, while in the IAHI cohort 4.38 ± 7.63 mg (p < 0.05). No adverse events related to either technique were recorded.

CONCLUSIONS

Intra-articular hip injection provides better pre-operatory pain management in elder patients with intracapsular hip fractures compared to the fascia-iliaca compartment block. It also reduced the need for supplementary systemic analgesia.

LEVEL OF EVIDENCE

Therapeutic Level I.

Use of Fentanyl Patch and Intravenous Morphine for Treatment of Leg Bone Fracture: Treatment Profile, and Clinical Effectiveness

BACKGROUND:

Severe pain is one of the major problems in patients with leg bone fracture. Various methods have been proposed to relieve pain. Opioids are one of the most important available medications to control these types of pain. Among the opioids available, fentanyl can be applied for its unique properties as transdermal patches.

AIM:

Therefore, the current study aimed to investigate the effect of intravenous morphine and fentanyl skin patch in patients with a lower leg fracture.

METHODS:

We entered 60 patients in this randomised, one-blind randomised clinical trial among patients referring to the emergency department of Vali-e-Asr Hospital in Arak with a fracture of the leg. Demographic and clinical data were recorded for patients. The case group (n = 30) received the fentanyl patch in the same area. Patients in the control group (30) received 0.1mcg/kg of morphine intravenously. In both groups, the severity of pain was measured every 20 minutes within two hours after onset of treatment based on VAS criteria and subsequently recorded in the checklist. Data were analysed by SPSS v.22 software package.

RESULTS:

The results of the present study demonstrated that the mean visual analogue scale (VAS) pain score at minutes 20, 40, 60 and 80 were statistically lower in intervention group when compared with the control group (p = 0.000).

CONCLUSION:

Our results indicated a considerable risk-benefit profile for the treatment of pain in patients suffering from dysphagia, nausea and vomiting, or resistance to other opioids. The use of fentanyl patch is also suitable for patients who are not able to take their medication at their scheduled time.

Opiate-Free Pain Therapy Using Carbamazepine-Loaded Microparticles Provides Up to 2 Weeks of Pain Relief in a Neuropathic Pain Model

INTRODUCTION

Opioids remain a mainstay in the treatment of acute and chronic pain, despite numerous and potentially dangerous side effects. There is a great unmet medical need for alternative treatments for patients suffering from pain that do not result in addiction or adverse side effects. Anticonvulsants have been shown to be effective in managing pain, though high systemic levels and subsequent side effects limit their widespread usage. Our goal was to determine if the incorporation of an anticonvulsant, carbamazepine, into a biodegradable microparticle for local sustained perineural release would be an efficacious analgesic following a peripheral injury.

METHODS

Following induction of the chronic constriction injury model in Sprague-Dawley rats, mechanical allodynia testing was performed using von Frey filaments and thermal allodynia was evaluated using the Hargreaves method. Histology and blood work were performed to evaluate toxicity as well as to monitor drug and metabolite presence over time.

RESULTS

A 2-fold increase in hindpaw withdrawal thresholds in animals receiving carbamazepine-loaded microparticles relative to controls was observed for up to 14 days after treatment. Drug and metabolite had a peak blood concentration of 54.7 ng/mL and dropped off exponentially to < 5 ng/mL over a few days.

CONCLUSION

This formulation reduced systemic exposure to carbamazepine over 1,000-fold relative to traditional analgesic dosing regimens. This 2-component drug delivery system has been specifically engineered to release a controlled amount of carbamazepine over a 14-day period, providing significant pain relief with no toxicological or observable adverse events via behavioral or histochemical analysis.

Effects of three forms of local anesthesia on perioperative fentanyl-induced hyperalgesia

Both local infiltration analgesia (LIA) and nerve block are common analgesic modalities for pain relief after surgery. The aim of the current study was to investigate the effects of those two modalities on pain behavior and the expression of pro-inflammatory cytokines such as interleukin (IL)-1β and IL-6 and tumor necrosis factor-α (TNF-α) in the spinal cord and dorsal root ganglion (DRG) in a rat model of perioperative fentanyl induced hyperalgesia. Rats were injected with fentanyl (60 μg/kg) 4 times and received a plantar incision after the second injection or they received pre-incision LIA and sciatic nerve block (SNB) or post-incision LIA with levobupivacaine (0.5%, 0.2 mL). Mechanical and thermal nociceptive thresholds were assessed using the tail pressure test and paw withdrawal test on the day before drug injection, 1 and 4 hours after injection, and 1-7 days later. The lumbar spinal cord and dorsal root ganglia were collected from rats in each group to measure IL-1β, IL-6, and TNF-α on the day before drug injection, 4 hours after injection, and 1, 3, 5, and 7 days later. Fentanyl and an incision induced a significantly delayed mechanical hyperalgesia in the tail and thermal hyperalgesia in both hind paws and up-regulation of pro-inflammatory cytokines in the spinal cord and dorsal root ganglia. Rats treated with pre-incision LIA and SNB or post-incision LIA had alleviated hyperalgesia and significantly reduced levels of IL-1β, IL-6, and TNF-α compared to the control group. LIA and SNB partly prevented perioperative fentanyl-induced hyperalgesia and up-regulation of pro-inflammatory cytokines in the spinal cord and dorsal root ganglia.