Prevention of postoperative pain by balanced analgesia

Fixed Dose Versus Loose Dose: Analgesic Combinations

Combinations of drugs may be fixed (two or more entities in a single product) or loose (two or more agents taken together but as individual agents) to help address multimechanistic pain. The use of opioids plus nonopioids can result in lower opioid consumption without sacrificing analgesic benefits. Drug combinations may offer additive or synergistic benefits. A variety of fixed-dose combination products are available on the market such as diclofenac plus thiocolchicoside, acetaminophen and caffeine, acetaminophen and opioid, ibuprofen and acetaminophen, tramadol and acetaminophen, and others. Fixed-dose combination products offer predictable pharmacokinetics and pharmacodynamics, known adverse events, and can reduce the pill burden. However, they are limited to certain drug combinations and doses; loose dosing allows prescribers the versatility to meet individual patient requirements as well as the ability to titrate as needed. Not all drug combinations offer synergistic benefits, which depend on the drugs and their doses. Certain drugs offer dual mechanisms of action in a single molecule, such as tapentadol, and these may further be used in combination with other analgesics. New technology allows for co-crystal productions of analgesic agents which may further improve drug characteristics, such as bioavailability. Combination analgesics are important additions to the analgesic armamentarium and may offer important benefits at lower doses than monotherapy.

Opioid-Sparing Techniques in Orthopedic Anesthesia-One Step to Opioid-Free Anesthesia?

Opioid-free anesthesia is a multimodal anesthesia aimed at avoiding the negative impact of intraoperative opioid on patient's postoperative outcomes. It is based on the physiology of pathways involved in intraoperative nociception. It has been shown to be feasible but the literature is still scarce on the clinically meaningful benefits as well as on the side effects and/or complications that might be associated with it. Moreover, most studies involved abdominal and/or bariatric surgery. Procedure-specific studies are lacking, especially in orthopedics.

Paracetamol for multimodal analgesia

Pain and related disability remain a major social and therapeutic problem. Comorbidities and therapies increase drug interactions and side effects making pain management more compounded especially in the elderly who are the fastest-growing pain population. Multimodal analgesia consists of using two or more drugs and/or techniques that target different sites of pain, increasing the level of analgesia and decreasing adverse events from treatment. Paracetamol enhances multimodal analgesia in experimental and clinical pain states. Strong preclinical evidence supports that paracetamol has additive and synergistic interactions with anti-inflammatory, opioid and anti-neuropathic drugs in rodent models of nociceptive and neuropathic pain. Clinical studies in young and adult elderly patients confirm the utility of paracetamol in multimodal, non-opioid or opioid-sparing, therapies for the treatment of acute and chronic pain.

Characterizing opioid consumption in the 30-day post-operative period following shoulder surgery: are we over prescribing?

Objectives: The primary aim of this study was to characterize opioid consumption in the first 30 days after shoulder surgery. Secondary aims were to assess patient expectations, pain tolerance, risk factors for increase opioid consumption, and proper disposal of narcotics.Methods: Patients undergoing rotator cuff repair (RCR), anatomic shoulder arthroplasty, reverse shoulder arthroplasty (RSA), distal clavicle resection, or labral surgery were prospectively enrolled. Collected data included demographics, Pain Catastrophizing Scale (PCS), pain tolerance surveys, narcotic use, adverse effects, and disposal method.Results: Eighty patients were included in this study. At 28 days, RCR patients took significantly more 5 mg oxycodone-equivalent pills than RSA patients (18.4 vs. 7.5; p = 0.001). Number of days on narcotics did not differ between groups. By day 14, 73 (92.5%) patients had stopped taking narcotics entirely, with 872 5 mg oxycodone-equivalent pills prescribed in surplus. Ten (14.3%) patients required an additional prescription. There was a significant difference in tobacco use (20% vs. 1.4%; p = 0.04), psychiatric history (50% vs. 5.7%; p = 0.0004) and PCS (12.7 vs. 7.1; p = 0.027) in these patients, with PCS of 12.5 as predictive of requiring another prescription.Conclusion: All patients achieved adequate pain control, with 60 (75%) patients having excess pills. Opioid utilization differed based on surgery - significantly lower use in RSA patients compared to RCR. Only 13 (16.25%) patients required more than 20 5 mg oxycodone-equivalent pills. Tobacco use, history of psychiatric illness, and PCS were risk factors for requiring more prescriptions.

Opioid-Sparing Anesthetic Technique for Pediatric Patients Undergoing Adenoidectomy: A Pilot Study

INTRODUCTION

An opioid-sparing anesthetic involves a multi-modal technique with non-opioid medications targeting different analgesic pathways. Such techniques may decrease adverse effects related to opioids. These techniques may be considered in patients at higher risk for opioid-related adverse effects including obstructive sleep apnea or sleep disordered breathing.

METHODS

A prospective, pilot study was performed in 10 patients (3-8 years of age), presenting for adenoidectomy. The perioperative regimen included oral dextromethorphan (1 mg/kg) and acetaminophen (15 mg/kg) plus single boluses of intraoperative dexmedetomidine (0.5 μg/kg) and ketamine (0.5 mg/kg). Pain scores were assessed in the post anesthesia care unit (PACU) using the FLACC (Face, Legs, Activity, Cry, Consolability) scale. Patients with a pain score >4 received fentanyl as needed. PACU time, pain scores, and parent satisfaction were recorded. Postoperatively, patients were instructed to use oral acetaminophen or ibuprofen every 6 hours as needed for pain.

RESULTS

The study cohort included 10 patients, 3-8 years of age. All patients had opioid-free anesthetic care. PACU time ranged from 24 to 102 minutes (median: 56 minutes). FLACC pain scores were 0 for all PACU assessments. Nine patients were discharged home and 1 patient had a planned overnight admission. Following hospital discharge, the pain scores were satisfactory during the 72-hour study period and 90% of the patients' guardians were satisfied or highly satisfied with their child's pain control.

CONCLUSION

This opioid-sparing approach provided safe and effective pain control as well as parental satisfaction following adenoidectomy in children. Additional prospective studies are needed to determine whether this regimen is effective in a larger cohort of patients with and for other otolaryngology procedures.

Interaction of Analgesic Effects of Dezocine and Sufentanil for Relief of Postoperative Pain: A Pilot Study

Purpose

The combination of dezocine and sufentanil is often used for postoperative analgesia in China and other areas, but the interaction of both two drugs is still unclear. The purpose of this study was to evaluate the interaction of the analgesic effects of dezocine and sufentanil in the patients after gynecological laparoscopic surgery.

Patients and Methods

We conducted a prospective, randomized, double-blinded clinical trial. A total of 150 patients were divided into 5 groups (30 in each group) in the post-anesthesia care unit, namely, dezocine group (Group D), sufentanil group (Group S) and dezocine mixed sufentanil groups (Group DS1-3). In group D and S, the initial dose of dezocine or sufentanil was 5mg and 5μg intravenously, respectively. In Group DS1, the initial dose was dezocine 5mg × 3/4 and sufentanil 5μg × 1/4. In Group DS2, the initial dose was dezocine 5mg × 1/2 and sufentanil 5μg × 1/2. In Group DS3, the initial dose was dezocine 5mg × 1/4 and sufentanil 5μg × 3/4.

Results

The median effective dose (ED50) of dezocine and sufentanil alone was 3.92 (95% confidence interval (CI) 3.01~4.64) mg and 3.71 (95% CI 2.78~4.39) μg, respectively. The isobolographic analysis showed that the combination of dezocine and sufentanil at 1:3, 1:1 or 3:1 appeared in the additive line.

Conclusion

In conclusion, when simultaneously administered intravenously, combined dezocine and sufentanil produce an additive effect for relieving the acute nociception after gynecological laparoscopic surgery.

Perioperative pain management for shoulder surgery: evolving techniques

Improving management of postoperative pain following shoulder surgery is vital for optimizing patient outcomes, length of stay, and decreasing addiction to narcotic medications. Multimodal analgesia (ie, controlling pain via multiple different analgesic methods with differing mechanisms) is an ever-evolving approach to enhancing pain control perioperatively after shoulder surgery. With a variety of options for the shoulder surgeon to turn to, this article succinctly reviews the pros and cons of each approach and proposes a potential pain management algorithm.

The Efficacy and Safety of Acetaminophen in Total Joint Arthroplasty: Systematic Review and Direct Meta-Analysis

BACKGROUND

Oral and intravenous (IV) acetaminophen has become widely used perioperatively as part of a multi-modal pain management protocol for primary total joint arthroplasty (TJA). The purpose of our study is to evaluate the efficacy and safety of acetaminophen in support of the combined clinical practice guidelines of the American Association of Hip and Knee Surgeons, American Academy of Orthopaedic Surgeons, Hip Society, Knee Society, and American Society of Regional Anesthesia and Pain Management.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for studies published prior to September 2019 on acetaminophen in primary TJA. All included studies underwent qualitative and quantitative homogeneity testing followed by a systematic review and direct comparison meta-analysis to assess the efficacy and safety of acetaminophen.

RESULTS

In total, 1287 publications were critically appraised yielding 17 publications representing the best available evidence for analysis. Oral and IV acetaminophen demonstrates the ability to safely reduce postoperative pain and opioid consumption during the inpatient hospital stay. No evidence was available to assess the efficacy and safety of oral acetaminophen after discharge.

CONCLUSION

Moderate evidence supports the use of oral and IV acetaminophen as a non-opioid adjunct for pain management during the inpatient hospitalization. Strong evidence supports the safety of oral and IV acetaminophen when appropriately administered to patients undergoing primary TJA. Although there is lack of robust evidence for use of acetaminophen following discharge, it remains a low-cost and low-risk option as part of a multimodal pain regimen.

Evolving the management of acute perioperative pain towards opioid free protocols: a narrative review

Objective: Identification of pain as the fifth vital sign has resulted in over-prescription and overuse of opioids in the US, with addiction reaching epidemic proportions. In Europe, and more recently in the US, a shift has occurred with the global adoption of multimodal analgesia (MMA), which seeks to minimize perioperative opioid use. Improved functional outcomes and reduced healthcare utilization costs have been demonstrated with MMA, but wide scale use of opioids in pain management protocols continues. As a next step in the pain management evolution, opioid-free analgesia (OFA) MMA strategies have emerged as feasible in many surgical settings.Methods: Articles were limited to clinical studies and meta-analyses focusing on comparisons between opioid-intensive and opioid-free/opioid-sparing strategies published in English.Results: In this review, elimination or substantial reduction in opioid use with OFA strategies for perioperative acute pain are discussed, with an emphasis on improved pain control and patient satisfaction. Improved functional outcomes and patient recovery, as well as reduced healthcare utilization costs, are also discussed, along with challenges facing the implementation of such strategies.Conclusions: Effective MMA strategies have paved the way for OFA approaches to postoperative pain management, with goals to reduce opioid prescriptions, improve patient recovery, and reduce overall healthcare resource utilization and costs. However, institution-wide deployment and adoption of OFA is still in early stages and will require personalization and better management of patient expectations.

Effectiveness of intravenous acetaminophen for postoperative pain management in shoulder arthroplasties: A population-based study

Background

Intravenous acetaminophen (IV APAP) is an option in multimodal postoperative analgesia. Prior trials focus on hip and knee arthroplasties, whereas large-scale data on utilization and effectiveness in shoulder arthroplasties are lacking.

Methods

Data on 67,494 (452 hospitals) partial/total shoulder arthroplasties were extracted from the Premier claims database (2011-2016). Patients were categorized by receipt and dosage of IV APAP. Multilevel models measured associations between IV APAP and opioid utilization (in oral morphine equivalents), length/cost of stay and opioid-related complications. Effect estimates (adjusted % change) with 95% confidence intervals (CIs) are reported.

Results

IV APAP was used in 17.7% (n = 11,949) of patients with an increasing utilization trend. Most patients received only one dose on the day of surgery (69.5%; n = 8308). When adjusting for relevant covariates, IV APAP was not associated with meaningful effects on outcomes. Specifically, its use (versus no use) was not associated with decreased (but rather somewhat increased) opioid utilization: + 5.4% (CI 3.6-7.1%; P < 0.05).

Conclusion

In this first large-scale study that assesses IV APAP in shoulder arthroplasties, IV APAP use was not associated with decreased opioid utilization or the length/cost of stay. These results do not support routine use of IV APAP in this cohort, especially given its high cost.

The translational potential for this article

Multimodal pain control to assist in reducing the opioid pain medications are seen as a route to improved postoperative patient outcomes, better pain control and expedited hospital discharge. Acetaminophen plays a significant role in these protocols in many institutions, but it is not established if this expensive IV formulation is superior to the oral formulation. This study evaluates the use and effectiveness of IV acetaminophen following shoulder arthroplasty at a large number of institutions.

The Influence of Etoricoxib on Pain Control for Laparoscopic Cholecystectomy: A Meta-analysis of Randomized Controlled Trials

INTRODUCTION

The efficacy of etoricoxib on pain control for laparoscopic cholecystectomy remains controversial. We conduct a systematic review and meta-analysis to explore the impact of etoricoxib on pain intensity after laparoscopic cholecystectomy.

MATERIALS AND METHODS

We searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through September 2018 for randomized controlled trials assessing the effect of etoricoxib versus placebo on pain management after laparoscopic cholecystectomy. This meta-analysis was performed using the random-effect model.

RESULTS

Four randomized controlled trials involving 351 patients are included in the meta-analysis. Overall, compared with control group for laparoscopic cholecystectomy, etoricoxib has no important impact on pain scores within 4 hours [mean difference (MD)=-1.48; 95% confidence interval (CI)=-3.54 to 0.58; P=0.16] and 8 hours (MD=-0.65; 95% CI=-1.43 to 0.12; P=0.10), but can significantly decrease pain intensity within 12 hours (MD=-1.16; 95% CI=-1.93 to -0.38; P=0.003) and 24 hours (MD=-1.10; 95% CI=-1.98 to -0.22; P=0.01), as well as postoperative analgesic consumption (standard MD=-1.21; 95% CI=-2.19 to -0.23; P=0.02), with no increase in nausea and vomiting (risk ratio=0.68; 95% CI=0.42-1.10; P=0.11), and headache (risk ratio=0.96; 95% CI=0.44-2.09; P=0.92).

CONCLUSIONS

Etoricoxib can substantially reduce pain intensity in patients with laparoscopic cholecystectomy.

Efficacy of intravenous acetaminophen in multimodal management for pain relief following total knee arthroplasty: a meta-analysis

Background

The efficacy of intravenous acetaminophen in multimodal pain management in patients undergoing total knee arthroplasty (TKA) is controversial. The purpose of this meta-analysis was to compare the efficacy of intravenous acetaminophen versus placebo in TKA.

Methods

Randomized controlled trials (RCTs) or retrospective cohort studies (RCSs) concerning related topics were retrieved from PubMed (1996–June 2018), Embase (1980–June 2018), and the Cochrane Library (CENTRAL June 2018). Any studies comparing intravenous acetaminophen with a placebo were included in this meta-analysis. Meta-analysis results were collected and analyzed by Stata 12.0. Subgroup analysis was performed according to the general characteristics of the patients.

Results

In total, the patients from six studies met the inclusion criteria. Our meta-analysis results indicated that compared with a control group, intravenous acetaminophen was associated with reductions in total morphine consumption and visual analogue scale (VAS) score at postoperative day (POD) 3. However, there was no significant difference in morphine consumption at POD 1 or in VAS at POD 1 or POD 2. Moreover, there was no significant difference in the length of hospital stay.

Conclusions

Based on our results, intravenous acetaminophen in multimodal management has shown better efficacy in pain relief at POD 3 and has morphine-sparing effects. High-quality studies with more patients are needed in the future.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0950-7) contains supplementary material, which is available to authorized users.

A prospective, randomized, double-blind, placebo-controlled trial of acute postoperative pain treatment using opioid analgesics with intravenous ibuprofen after radical cervical cancer surgery

This study assessed the efficacy and tolerability of intravenous ibuprofen in the improvement of post-operative pain control and the reduction of opioid usage. Patients were randomly divided into placebo, ibuprofen 400 mg and ibuprofen 800 mg groups. All patients received patient-controlled intravenous morphine analgesia after surgery. The first dose of study drugs was administered intravenously 30 min before the end of surgery and then every 6 hours, for a total of 8 doses after surgery. The primary endpoint of this study was the mean amount of morphine used during the first 24 hours after surgery. Morphine use was reduced significantly in the ibuprofen 800 mg group compared with the placebo group (P = 0.04). Tramadol use was reduced significantly in the ibuprofen 400 mg and ibuprofen 800 mg groups compared with the placebo group (P < 0.01). The area under the curve of visual analog scale pain ratings was not different between groups. Safety assessments and side effects were not different between the three groups. Intravenous ibuprofen 800 mg was associated with a significant reduction in morphine requirements, and it was generally well tolerated for postoperative pain management in patients undergoing radical cervical cancer surgery.

Intravenous vs Oral Acetaminophen as an Adjunct to Multimodal Analgesia After Total Knee Arthroplasty: A Prospective, Randomized, Double-Blind Clinical Trial

BACKGROUND

The efficacy of intravenous (IV) acetaminophen compared with its oral formulation for postoperative analgesia is unknown. We hypothesized that the addition of acetaminophen to a multimodal analgesia regimen would provide improved pain management in patients after total knee arthroplasty (TKA) and that the effect of acetaminophen would be variable based on the route of delivery.

METHODS

The study was a single-center, randomized, double-blinded, placebo-controlled clinical trial on the efficacy of IV vs oral acetaminophen in patients undergoing unilateral TKA. One hundred seventy-four subjects were randomized to one of the 3 groups: IV acetaminophen group (IV group, n = 57) received 1 g IV acetaminophen and oral placebo before postanesthesia care unit (PACU) admission; oral acetaminophen group (PO group, n = 58) received 1 g oral acetaminophen and volume-matched IV normal saline; placebo group (Placebo group, n = 59) received oral placebo and volume-matched IV normal saline. Pain scores were obtained every 15 minutes during PACU stay. Average pain scores, maximum pain score, and pain scores before physical therapy were compared among the 3 groups. Secondary outcomes included total opiate consumption, time to PACU discharge, time to rescue analgesia, and time to breakthrough pain.

RESULTS

The average PACU pain score was similar in the IV group (0.56 ± 0.99 [mean ± standard deviation]) compared with the PO group (0.67 ± 1.20; P = .84) and Placebo group (0.58 ± 0.99; P = .71). Total opiate consumption at 6 hours (0.47 mg hydromorphone equivalents ± 0.56 vs 0.54 ± 0.53 vs 0.54 ± 0.61; P = .69) and at 24 hours (1.25 ± 1.30 vs 1.49 ± 1.34 vs 1.36 ± 1.31; P = .46) were also similar between the IV, PO, and Placebo groups. No significant differences were found between all groups for any other outcome.

CONCLUSION

Neither IV nor oral acetaminophen provides additional analgesia in the immediate postoperative period when administered as an adjunct to multimodal analgesia in patients undergoing TKA in the setting of a spinal anesthetic.

Local infiltration analgesia with ropivacaine in acute fracture of thoracolumbar junction surgery

STUDY DESIGN

Retrospective study.

INTRODUCTION

Local infiltration analgesia is effective in many surgeries as knee arthroplasty, but the analgesic efficacy of local infiltration analgesia with ropivacaine in trauma spine surgery in T10 to L2 has not been clarified. We conducted a trial to assess the analgesic efficacy of intraoperative local infiltration analgesia (LIA) with ropivacaine.

OBJECTIVE

The aim of the present study was to clarify the effect of intraoperative local infiltration analgesia with ropivacaine on postoperative pain for patients undergoing thoracolumbar junction fracture surgery.

METHODS

In a retrospective study, in 76 patients undergoing spine surgery for thoracolumbar junction fracture, 20ml of ropivacaine 7.5% (n R group=38) was infiltrated using a systematic technique, or no infiltration was realized (n M group=38). We assessed postoperative pain with Visual Analogue Scale (VAS) and morphine consumption in the 24 first hours.

RESULTS

VAS pain score upon awakening and at 2hours postoperatively were significantly lower in the ropivacaine group (P=0.01 and P=0.002). Rescue opioid requirement during the 24 first hours were about 50% lower in the ropivacaine group (P=0.01). No local or systemic side effects were observed.

CONCLUSION

Intraoperative LIA with ropivacaine in thoracolumbar junction fracture surgery may have an analgesic effect in postoperative pain control (24hours) with a reduction of VAS and morphine consumption.

Effectiveness of Liposomal Bupivacaine in Colorectal Surgery: A Pragmatic Nonsponsored Prospective Randomized Double Blinded Trial in a Community Hospital

BACKGROUND

Prior industry conducted studies have shown that long acting liposomal bupivacaine injection improves pain control postoperatively.

OBJECTIVE

To evaluate whether liposomal bupivacaine reduced the use of postoperative opioid (http://links.lww.com/DCR/A253) pain medication as compared to standard bupivacaine following colorectal surgery.

DESIGN

A double blinded, prospective, randomized controlled trial comparing liposomal bupivacaine versus standard bupivacaine in patients undergoing elective colon resection.

SETTINGS

Community hospital with general surgery residency program with all cases performed by colorectal surgeons.

PATIENTS

Fifty-seven patients were randomized and reported as intention-to-treat analysis with 6 protocol violations. Sensitivity analysis excluding these 6 patients demonstrated no change in study results or conclusion. Mean age was 67 ± 2 years and 56% were male. There were 36 patients who underwent minimally invasive surgery, and 21 patients had an open colon resection.

INTERVENTIONS

Experimental arm received liposomal bupivacaine while control arm received standard bupivacaine.

MAIN OUTCOME MEASURES

Primary outcome measure was intravenous hydromorphone equivalent used via PCA during first 48 hours after operation.

RESULTS

There was no significant difference between the two groups in the amount of opioid used orally or intravenously in the postoperative period. The primary outcome measure was PCA hydromorphone consumption during first two postoperative days after operation (hydromorphone equivalent use in standard bupivacaine group 11.3 ± 8.9 mg versus 13.3 ± 11.9 mg in liposomal bupivacaine group, p = 0.58 Mann-Whitney test).

LIMITATIONS

Small pragmatic trials typically remain underpowered for secondary analyses. A larger study could help to further delineate other outcomes that are impacted by postoperative pain.

CONCLUSIONS

Liposomal bupivacaine did not change the amount of opioid used postoperatively. Based on our study, liposomal bupivacaine does not provide any added benefit over conventional bupivacaine after colon resection. (ClinicalTrials.gov: NCT02052557).

Effect of Administration of Ketorolac and Local Anaesthetic Infiltration for Pain Relief after Laparoscopic-assisted Vaginal Hysterectomy

The efficacy of local anaesthetic infiltration and/or non-steroidal anti-inflammatory drugs for post-operative analgesia following laparoscopic-assisted vaginal hysterectomy (LAVH) was investigated in 83 patients, randomized into four groups in this double-blind, placebo-controlled study: group BK, local infiltration with bupivacaine and pre-incisional intramuscular (IM) ketorolac; group NN, saline local infiltration IM; group BN, local infiltration with bupivacaine and saline IM; group NK, local infiltration with saline and ketorolac IM. Post-operative pain scores were assessed at 1 h, 3 h, 6 h, 12 h and 24 h using a visual analogue scale (VAS). The major pain site, first analgesic request time and incidence of analgesic requests were also recorded. At 1 h, 3 h and 6 h after surgery, group BK patients had significantly lower VAS pain scores than group NN patients. The first analgesic request time was significantly longer in group BK than in groups NN, BN and NK. Pre-incisional treatment with ketorolac IM and local infiltration with bupivacaine reduced post-operative pain after LAVH.

[Postoperative non-opioid analgesics management]

Morphine, which is known as the reference analgesic, has shown its limits. Reducing morphine consumption and multimodal analgesia are integral parts of a modern management of postoperative pain. Combination of several analgesics aims for improving pain control and the ratio between the analgesic effect and the side effects. Nefopam, paracetamol, non-steroids anti-inflammatory drugs and steroids are the most frequently prescribed non-opioid analgesics in France. They can be administered alone or in combination with or without morphine in the postoperative setting. The analgesic benefit of each of these agents and their associations is variable and described in details in this manuscript.

Intravenous non-opioid analgesia for peri- and postoperative pain management: a scientific review of intravenous acetaminophen and ibuprofen

Pain is a predictable consequence following operations, but the management of postoperative pain is another challenge for anesthesiologists and inappropriately controlled pain may lead to unwanted outcomes in the postoperative period. Opioids are indeed still at the mainstream of postoperative pain control, but solely using only opioids for postoperative pain management may be connected with risks of complications and adverse effects. As a consequence, the concept of multimodal analgesia has been proposed and is recommended whenever possible. Acetaminophen is one of the most commonly used analgesic and antipyretic drug for its good tolerance and high safety profiles. The introduction of intravenous form of acetaminophen has led to a wider flexibility of its use during peri- and postoperative periods, allowing the early initiation of multimodal analgesia. Many studies have revealed the efficacy, safety and opioid sparing effects of intravenous acetaminophen. Intravenous ibuprofen has also shown to be well tolerated and demonstrated to have significant opioid sparing effects during the postoperative period. However, the number of randomized controlled trials confirming the efficacy and safety is small and should be used in caution in certain group of patients. Intravenous acetaminophen and ibuprofen are important options for multimodal postoperative analgesia, improving pain and patient satisfaction.

Treatment of acute abdominal pain in the emergency room: a systematic review of the literature

Appropriate pain therapy prior to diagnosis in patients with acute abdominal pain remains controversial. Several recent studies have demonstrated that pain therapy does not negatively influence either the diagnosis or subsequent treatment of these patients; however, current practice patterns continue to favour withholding pain medication prior to diagnosis and surgical treatment decision. A systematic review of PubMed, Web-of-Science and The-Cochrane-Library from 1929 to 2011 was carried out using the key words of 'acute', 'abdomen', 'pain', 'emergency' as well as different pain drugs in use, revealed 84 papers. The results of the literature review were incorporated into six sections to describe management of acute abdominal pain: (1) Physiology of Pain; (2) Common Aetiologies of Abdominal Pain; (3) Pre-diagnostic Analgesia; (4) Pain Therapy for Acute Abdominal Pain; (5) Analgesia for Acute Abdominal Pain in Special Patient Populations; and (6) Ethical and Medico-legal Considerations in Current Analgesia Practices. A comprehensive algorithm for analgesia for acute abdominal pain in the general adult population was developed. A review of the literature of common aetiologies and management of acute abdominal pain in the general adult population and special patient populations seen in the emergency room revealed that intravenous administration of paracetamol, dipyrone or piritramide are currently the analgesics of choice in this clinical setting. Combinations of non-opioids and opioids should be administered in patients with moderate, severe or extreme pain, adjusting the treatment on the basis of repeated pain assessment, which improves overall pain management.

A single-center, randomized, double-blind, active, and placebo-controlled study of KAI-1678, a novel PKC-epsilon inhibitor, in the treatment of acute postoperative orthopedic pain

OBJECTIVE

KAI-1678, a novel inhibitor of the interaction of the epsilon isoform of protein kinase C (εPKC) with its intracellular receptor, has demonstrated activity in countering hyperalgesia in several models of pain. In this controlled randomized trial, KAI-1678 was tested for analgesic activity in an orthopedic acute postoperative pain setting.

DESIGN

Following hip or knee replacement surgery, subjects were treated with KAI-1678, ketorolac, or saline. Subjects recorded their pain intensity on a visual analog scale and rated their quality of analgesia. The pain intensity differences between baseline and the evaluations were summed over the first 4 hours.

RESULTS

The analysis revealed that, while ketorolac displayed good analgesic activity, KAI-1678 was not significantly different than placebo. Analgesia quality ratings similarly did not show a difference between KAI-1678 and placebo in this pain model. A small excess of infusion site erythema was seen with KAI-1678, but otherwise the drug was safe and well tolerated.

CONCLUSIONS

We investigated the safety and efficacy of a novel inhibitor of εPKC and provide clinical evidence that inhibition of εPKC with KAI-1678 is not effective in the treatment of acute postoperative orthopedic pain.

Intravenous paracetamol reduced the use of opioids, extubation time, and opioid-related adverse effects after major surgery in intensive care unit

BACKGROUND

This study assessed the analgesic efficacy, side effects, and time to extubation of intravenous paracetamol when administered as an adjuvant to intravenous meperidine after major surgery in intensive care unit (ICU).

MATERIAL

Patients were randomized postoperatively into 2 groups in ICU. Patients received either 100 mL of serum saline intravenous (IV) every 6 hours and IV meperidine (n = 20 group M) or IV paracetamol 1 g every 6 hours and IV meperidine (n = 20, group MP) into a peripheral vein for 24 hours. Behavioral Pain Scale (BPS) is used until extubation, and visual analog score (VAS) is used after extubation. When BPS and VAS values were more than 4, meperidine, 1 mg/kg IV, was administered and noted in 2 groups. Pain scores, total meperidine consumption, time to extubation, sedation scores, and side effects are 24-hour postoperatively noted.

RESULTS

Behavioral Pain Scale and VAS scores are significantly lower in group paracetamol-meperidine at 24 hours (P < .05). In group MP, postoperative meperidine consumption (76.75 ± 18.2 mg vs. 198 ± 66.4 mg) and extubation time (64.3 ± 40.6 min vs. 204.5 ± 112.7 min) were lower than in group M (P < .01). In addition to, postoperative nausea-vomiting and sedation scores were significantly lower in group MP when compared with group M (P < .05).

CONCLUSION

We have demonstrated important clinical benefits by the addition of 4 g/d of paracetamol to meperidine after major surgery. This benefit has been shown in a range of patients under routine clinical conditions and therefore has important practical consequences in ICU. These data suggest that intravenous paracetamol is a useful component of the multimodal analgesia model, especially after major surgery.

Subarachnoid morphine, bupivacaine and fentanyl as part of combined spinal-epidural analgesia for low anterior resection. A prospective, randomised, double-blind clinical trial

This study was designed to compare the efficacy of subarachnoid morphine alone or in combination with bupivacaine and fentanyl for combined spinal-epidural analgesia in colorectal surgery. This is a prospective, randomised, double-blind clinical trial. Sixty patients undergoing low anterior resection were assigned to one of three groups: subarachnoid morphine, bupivacaine and fentanyl, subarachnoid morphine and bupivacaine or subarachnoid morphine only. Epidural catheter placement and subarachnoid injection were done via a combined spinal-epidural Epistar needle at L2-3. The epidural catheter was used for scheduled intraoperative bupivacaine and intermittent postoperative bupivacaine and morphine administration. Intraoperative epidural bupivacaine, intraoperative intravenous fentanyl use, time to first analgesia request, postoperative visual analogue scale pain scores, tramadol requirements and side-effects were recorded for 72 hours. Postoperative analgesia was comparable in all groups. Intraoperative fentanyl and bupivacaine consumption was lowest in the morphine, bupivacaine and fentanyl group. Time to first analgesia request was longer in the morphine, bupivacaine and fentanyl compared to the morphine group (P = 0.009). Tramadol use was lower in the morphine and bupivacaine group compared to morphine, bupivacaine and fentanyl (P = 0.017) on postoperative day two. There were no significant adverse effects. All patients ambulated the morning after surgery. The addition of bupivacaine and fentanyl to subarachnoid morphine did not confer any advantage on postoperative visual analogue scale scores and tramadol use, but lowered the need for additional intraoperative intravenous fentanyl and epidural bupivacaine and prolonged the time to first analgesia request.

[Mild to moderate postoperative pain: the PATHOS survey results for Spain versus other European countries]

OBJECTIVES

The Postoperative Analgesic Therapy Observational Survey (PATHOS) was designed to identify the current state of postoperative pain in specific areas and the needs and opportunities for improving treatment. We compared the results obtained in Spain with those obtained in the rest of Europe between August 2004 and June 2005.

MATERIAL AND METHODS

A prospective observational multicenter, multinational study in 7 European countries. The data on postoperative pain management were obtained anonymously by means of a standardized multiple-choice questionnaire.

RESULTS

Participation was higher among surgeons (68%) in Spain and among anesthesiologists (69%) in other European countries. Systematic presurgical information on the treatment of postoperative pain was provided to 22.2% of patients undergoing surgery in Spain. Organized structures for the treatment of postoperative pain are less common in Spanish hospitals (47%) than in other European hospitals (69%). Anesthesiologists are less often those who inform patients about postoperative pain in Spain than in other European countries. Only 25.9% of Spanish hospitals have written protocols for treating postoperative pain. Pain was not evaluated in 39% of patients who underwent surgery in Spain.

CONCLUSIONS

There is inadequate treatment of postoperative pain, and the problem is greater in Spain than in the other European countries participating in PATHOS. The results should help to identify opportunities for improvement.

Combined spinal-epidural analgesia vs. intermittent bolus epidural analgesia for pain relief after major abdominal surgery. A prospective, randomised, double-blind clinical trial

BACKGROUND

The primary aim of this study was to compare the efficacy of combined spinal-epidural (CSE) analgesia vs. intermittent bolus epidural analgesia (EA) for pain relief after major abdominal surgery. The secondary aim was to assess the effects of fentanyl addition to subarachnoid morphine and bupivacaine.

METHODS

This was a prospective, randomised, double-blind trial; 160 patients scheduled for major abdominal surgery enrolled. All patients had a thoracic epidural catheter for administration of intra-operative and postoperative analgesia. Patients were assigned to one of four groups: (i) subarachnoid morphine, bupivacaine and fentanyl (MBF group); (ii) morphine and bupivacaine (MB group); (iii) morphine (M group) and (iv) normal saline (EA group). Use of additional intravenous (i.v.) fentanyl and epidural bupivacaine was recorded to measure the need for supplemental intra-operative analgesia. Pain at rest, with movement, and with cough (measured with a visual analogue scale), additional analgesia requests, and side effects were recorded over 72 h postoperatively.

RESULTS

Compared with the EA group, the MBF group had significantly reduced pain with cough and lower analgesia requirements during the first 24 h (p<0.001) and after EA discontinuation (p=0.041). The MBF group required less intra-operative epidural bupivacaine compared with all other groups (p<0.001), and less intra-operative i.v. fentanyl compared with group M (p<0.001).

CONCLUSIONS

Combined spinal-epidural improved intra-operative analgesia and reduced pain with cough in the immediate postoperative period. The addition of fentanyl to subarachnoid morphine and bupivacaine decreased the need for additional i.v. fentanyl and epidural bupivacaine analgesia.

Intravenous paracetamol as adjunctive treatment for postoperative pain after cardiac surgery: a double blind randomized controlled trial

BACKGROUND

Nonsteroidal anti-inflammatory drugs and opioids are routinely used after cardiac surgery in order to mitigate postoperative pain; however, these drugs are burdened by side effects. Tramadol and paracetamol are believed to be lacking in such side effects. The aim of this study was to examine the efficacy of intravenous paracetamol as an adjunctive analgesic to a tramadol-based background analgesia after cardiac surgery.

METHODS

A total of 113 patients participated in this single center, placebo-controlled, double-blind, randomized trial. Fifty-six patients were randomized to receive paracetamol and 57 to placebo. Intravenous study drug (1 g) was administered 15 min before the end of surgery and every 6h for 72 h. Standard analgesia (tramadol) and anti-emetic prophylactic regimen (ondansetron) were available to both patient groups. Postoperative pain was evaluated by visual analog scale, and it was measured at rest and during a deep breath. A rescue dose of 2-5 mg of intravenous morphine was administered whenever the VAS score was greater than 3.

RESULTS

Baseline characteristics were equivalent between the two groups. At 12, 18, 24 h after the end of operation, patients who received paracetamol had significantly less pain at rest (p=0.0041, 0.0039, 0.0044, respectively); after this time the two groups did not differ. During a deep breath the difference was significant only at 12 h (p=0.0040). Paracetamol group required less cumulative morphine than placebo group (48 mg vs 97 mg) even if the difference did not reach statistical significance (p=0.274).

CONCLUSIONS

In patients undergoing cardiac surgery, intravenous paracetamol in combination with tramadol provides effective pain control.

Postoperative Analgesic THerapy Observational Survey (PATHOS): a practice pattern study in 7 central/southern European countries

Surveys evaluating pain in hospitals keep on showing that postoperative pain (POP) remains undertreated. At the time when guidelines are edited and organisational changes are implemented, more recent data are necessary to check the impact of these measures on daily practice and needs for improvement. This prospective, cross-sectional, observational, multi-centre practice survey was performed in 2004-2005 in 7 European countries. It was conducted in surgical wards of a randomised sample of hospitals. Data on POP management practices following surgery in adult in-patients were collected anonymously via a standardised multiple choice questionnaire. Among 1558 questionnaires received from 746 European hospitals, 59% were provided by anaesthetists and 41% by surgeons. There are no regular on-site staff training programmes on POP management in the institution for 34% of the respondents, patients are systematically provided with POP information before surgery for 48% of respondents; balanced analgesia following major surgery and regular administration of analgesics are largely used; 25% of respondents have specific written POP management protocols for all patients in their ward; 34% of respondents say that pain is not assessed and 44% say that pain scores are documented in the patient's chart. This largest ever performed survey confirms the extensive body of evidence that current POP management remains suboptimal and identifies needs for improvement on European surgical wards. However, the wide use of balanced analgesia and the regular administration of analgesics are indicators of ongoing change.

Preventing the development of chronic pain after orthopaedic surgery with preventive multimodal analgesic techniques

The prevalences of complex regional pain syndrome, phantom limb pain, chronic donor-site pain, and persistent pain following total joint arthroplasty are alarmingly high. Central nervous system plasticity that occurs in response to tissue injury may contribute to the development of persistent postoperative pain. Many researchers have focused on methods to prevent central neuroplastic changes from occurring through the utilization of preemptive or preventive multimodal analgesic techniques. Multimodal analgesia allows a reduction in the doses of individual drugs for postoperative pain and thus a lower prevalence of opioid-related adverse events. The rationale for this strategy is the achievement of sufficient analgesia due to the additive effects of, or the synergistic effects between, different analgesics. Effective multimodal analgesic techniques include the use of nonsteroidal anti-inflammatory drugs, local anesthetics, alpha-2 agonists, ketamine, alpha(2)-delta ligands, and opioids.

The impact of opioid-induced hyperalgesia for postoperative pain

Clinical evidence suggests that--besides their well known analgesic activity - opioids can increase rather than decrease sensitivity to noxious stimuli. Based on the observation that opioids can activate pain inhibitory and pain facilitatory systems, this pain hypersensitivity has been attributed to a relative predominance of pronociceptive mechanisms. Acute receptor desensitization via uncoupling of the receptor from G-proteins, upregulation of the cAMP pathway, activation of the N-methyl-D-aspartate (NMDA)-receptor system, as well as descending facilitation, have been proposed as potential mechanisms underlying opioid-induced hyperalgesia. Numerous reports exist demonstrating that opioid-induced hyperalgesia is observed both in animal and human experimental models. Brief exposures to micro-receptor agonists induce long-lasting hyperalgesic effects for days in rodents, and also in humans large-doses of intraoperative micro-receptor agonists were found to increase postoperative pain and morphine consumption. Furthermore, the prolonged use of opioids in patients is often associated with a requirement for increasing doses and the development of abnormal pain. Successful strategies that may decrease or prevent opioid-induced hyperalgesia include the concomitant administration of drugs like NMDA-antagonists, alpha2-agonists, or non-steroidal anti-inflammatory drugs (NSAIDs), opioid rotation or combinations of opioids with different receptor/selectivity.

The median effective dose of tramadol and morphine for postoperative patients: a study of interactions

Tramadol is a centrally-acting analgesic drug. In a search of an effective balanced analgesia technique with a morphine-sparing component, we studied the median effective analgesic doses (ED(50)) of tramadol, morphine, and their combination to determine the nature of their interaction using an isobolographic analysis. In this double-blind, randomized, two-stage prospective study, 90 postoperative patients were enrolled in one of three groups. The dose of tramadol and morphine received by a particular patient was determined using an up-down allocation technique. Initial doses and increments were, respectively, 100 mg and 10 mg in the tramadol group and 5 mg and 1 mg in the morphine group. In the second part, a 40:3 tramadol:morphine dosing ratio was used. The threshold of effective analgesia was defined as 3 or less on a numerical pain score (0-10). Isobolographic analysis was subsequently applied. The ED(50) values (95% confidence interval) of tramadol and morphine were, respectively, 86 mg (57-115 mg) and 5.7 mg (4.2-7.2 mg). The ED(50) of the combination was 72 mg (62-82 mg) for tramadol and 5.4 mg (4-6.6.2 mg) for morphine. The combination of tramadol and morphine was infra-additive and thus not recommended for postoperative analgesia.

[Opioid-induced hyperalgesia. Pathophysiology and clinical relevance]

Opioids are the drugs of choice for the treatment of moderate to severe acute and chronic pain. However, clinical evidence suggests that opioids can elicit increased sensitivity to noxious stimuli suggesting that administration of opioids can activate both pain inhibitory and pain facilitatory systems. Acute receptor desensitization via uncoupling of the receptor from G-proteins, up-regulation of the cAMP pathway, activation of the N-methyl-D-aspartate (NMDA) receptor system, as well as descending facilitation, have been proposed as potential mechanisms underlying opioid-induced hyperalgesia. Numerous reports exist demonstrating that opioid-induced hyperalgesia is observed both in animal and human experimental models. Brief exposures to micro-receptor agonists induce long-lasting hyperalgesic effects for days, which might by reflected by clinical observations that large doses of intraoperative micro-receptor agonists increased postoperative pain and morphine consumption. Furthermore, the prolonged use of opioids in patients often requires increasing doses and may be accompanied by the development of abnormal pain. Successful strategies that may decrease or prevent opioid-induced hyperalgesia include the concomitant administration of drugs like NMDA-antagonists, alpha(2)-agonists, or non-steroidal anti-inflammatory drugs (NSAIDs), opioid rotation or combinations of opioids with different receptor selectivity.