Predicting postoperative analgesia outcomes: NNT league tables or procedure-specific evidence?

Novel Targets and Drug Delivery System in the Treatment of Postoperative Pain: Recent Studies and Clinical Advancement

Pain is generated by a small number of peripheral targets. These can be made more sensitive by inflammatory mediators. The number of opioids prescribed to the patients can be reduced dramatically with better pain management. Any therapy that safely and reliably provides extended analgesia and is flexible enough to facilitate a diverse array of release profiles would be useful for improving patient comfort, quality of care, and compliance after surgical procedures. Comparisons are made between new and traditional methods, and the current state of development has been discussed; taking into account the availability of molecular and cellular level data, preclinical and clinical data, and early post-market data. There are a number of benefits associated with the use of nanotechnology in the delivery of analgesics to specific areas of the body. Nanoparticles are able to transport drugs to inaccessible bodily areas because of their small molecular size. This review focuses on targets that act specifically or primarily on sensory neurons, as well as inflammatory mediators that have been shown to have an analgesic effect as a side effect of their anti- inflammatory properties. New, regulated post-operative pain management devices that use existing polymeric systems were presented in this article, along with the areas for potential development. Analgesic treatments, both pharmacological and non-pharmacological, have also been discussed.

Regional anesthesia does not decrease inpatient or outpatient opioid demand in distal femur fracture surgery

INTRODUCTION

Regional anesthesia (RA) is sometimes used to decrease pain and opioid consumption in distal femur fractures. However, the real-world impact of RA on inpatient opioid consumption and outpatient opioid demand is not well known. The hypothesis of this study is that RA would be associated with decreased inpatient opioid consumption and outpatient opioid demand.

METHODS

This study evaluated inpatient post-operative opioid consumption (0-24 h, 24-48 h, 48-72 h) and outpatient opioid demand (discharge to 2 weeks, 6 weeks, and 90 days) in all patients ages 18 and older undergoing operative treatment of distal femur fractures at a single institution from 7/2013 to 7/2018 (n = 230). Unadjusted and adjusted multivariable models were used to evaluate the impact of RA and other baseline patient and operative characteristics on inpatient opioid consumption and outpatient opioid demand.

RESULTS

Adjusted models demonstrated a small, significant increase in inpatient opioid consumption in patients with RA compared to no RA (4.7 estimated OE's without RA vs 6.2 OE's with RA from 24- to 48-h post-op, p < 0.05) but otherwise no significant differences at other timepoints (6.7 estimated OE's without RA vs 6.9 OE's with RA from 0- to 24-h post-op and 4.5 vs 4.4 from 48- to 72-h post-op, p > 0.05). Estimated cumulative outpatient opioid demand was significantly higher in patients with RA from discharge to 6 weeks and to 90 days (55.8 OE's without RA vs 63.9 with RA from discharge to 2 weeks, p > 0.05; 74.9 vs 95.1 OE's to 6 weeks, and 85 vs 113.1 OE's to 90 days, p < 0.05).

DISCUSSION

In distal femur fracture surgery, RA was associated with increased inpatient and outpatient opioid demand after adjusting for baseline patient and treatment characteristics. These results call into question the routine use of RA in distal femur fractures.

LEVEL OF EVIDENCE

Level III, retrospective, therapeutic cohort study.

The Application of Acupuncture Therapy for Postoperative Pain Over the Past 20 Years: A Bibliometric Analysis

PURPOSE

The purpose of this study is to analyze and visualize the research trends on acupuncture therapy for postoperative pain over the past 20 years to identify hotspots and frontiers, and provide new research ideas.

METHODS

A search of the Web of Science database, with a time frame of 2001-01-01 to 2022-02-28, was conducted to collect literatures related to acupuncture therapy for postoperative pain. A bibliometric analysis and visualization of results was performed using CiteSpace software for the volume of annual publications, journals, countries, institutions, authors, keywords, and references.

RESULTS

A total of 840 literatures were eventually included in the analysis. The number of publications has fluctuated upwards each year over the past 20 years and reached a peak in the latest three years. Evidence-Based Complementary and Alternative Medicine was the journal with the most relevant publications and Pain was the most frequently cited journal. The country with the highest volume of publications was China, and the USA contributed most to the international collaboration. The most prolific and influential authors were Inhyunk Ha and Han JS respectively. The most frequent keyword was "acupuncture". References with highest frequency or centrality were both systematic evaluations focusing on different acupuncture therapies for postoperative pain relief.

CONCLUSION

The field of acupuncture therapy for postoperative pain is currently in a period of high growth. China and the USA have made the largest contribution to the volume of publications. The most influential institutions and authors are mainly from China and South Korea. The overall collaborative network needs to be strengthened. Electroacupuncture and auricular acupuncture (therapeutic techniques), low back surgery (types of surgery), and "postoperative pain, nausea and vomiting" are research hotspots in this field. Improvement of postoperative life quality, proof of clinical efficacy and evidence-based evaluation are the current research trends and frontiers.

Regional Anesthesia Associated With Decreased Inpatient and Outpatient Opioid Demand in Tibial Plateau Fracture Surgery

BACKGROUND

Regional anesthesia (RA) has been used to reduce pain and opioid usage in elective orthopedic surgery. The hypothesis of this study was that RA would be associated with decreased opioid demand in tibial plateau fracture surgery.

METHODS

Inpatient opioid consumption and 90-day outpatient opioid prescribing in all patients ≥18 years of age undergoing tibial plateau fracture surgery from July 2013 to July 2018 (n = 264) at a single, level I trauma center were recorded. The presence or absence of perioperative RA was noted. Of 60 patients receiving RA, 52 underwent peripheral nerve blockade (PNB) with single-shot sciatic-popliteal (40.0%; n = 24), femoral (26.7%; n = 16), adductor canal (18.3%; n = 11), or fascia iliaca (1.7%; n = 1) block with ropivacaine. Ten patients received epidural analgesia (EA) with either single-shot spinal (11.7%; n = 7) blocks or continuous epidural (5.0%; n = 3). Additional baseline and treatment characteristics were recorded, including age, sex, race, body mass index (BMI), smoking, chronic opioid use, American Society of Anesthesiologists (ASA) score, injury mechanism, additional injuries, open injury, and additional inpatient surgery. Statistical models, including multivariable generalized linear models with propensity score weighting to adjust for baseline patient and treatment characteristics, were used to assess perioperative opioid demand with and without RA.

RESULTS

RA was associated with reduced inpatient opioid usage from 0 to 24 hours postoperatively of approximately 5.2 oxycodone 5-mg equivalents (0.74 incident rate ratio [IRR]; 0.63-0.86 CI; P < .001) and from 24 to 48 hours postoperatively of approximately 2.9 oxycodone 5-mg equivalents (0.78 IRR; 0.64-0.95 CI; P = .014) but not at 48 to 72 hours postoperatively. From 1 month preoperatively to 2 weeks postoperatively, RA was associated with reduced outpatient opioid prescribing of approximately 24.0 oxycodone 5-mg equivalents (0.87; 0.75-0.99; P = .044) and from 1 month preoperatively to 90 days postoperatively of approximately 44.0 oxycodone 5-mg equivalents (0.83; 0.71-0.96; P = .011), although there was no significant difference from 1 month preoperatively to 6 weeks postoperatively. There were no cases of acute compartment syndrome in this cohort.

CONCLUSIONS

In tibial plateau fracture surgery, RA was associated with reduced inpatient opioid consumption up to 48 hours postoperatively and reduced outpatient opioid demand up to 90 days postoperatively without an associated risk of acute compartment syndrome. RA should be considered for patients undergoing tibial plateau fracture fixation.

A Randomized Controlled Trial Comparing Intravenous Lidocaine Infusion With Thoracic Epidural for Perioperative Analgesia and Quality of Recovery After Surgery in Laparoscopic Left-Sided Colon and Sphincter-Sparing Rectal Resection Surgery

Background Protocols for Enhanced Recovery after Surgery (ERAS) have been constantly evolving, and the best method of managing perioperative pain, especially in laparoscopic surgeries, is still debatable. The primary goal of these protocols is to steer toward opioid-sparing analgesia. Intravenous lidocaine, which has both analgesic and anti-inflammatory properties, may improve the overall recovery of patients. Objectives The aim of this randomized controlled trial was to compare the efficacy of intravenous lidocaine infusion (IVL) with thoracic epidural analgesia (TEA) in the management of perioperative pain and recovery in the laparoscopic left-sided colon and sphincter-sparing rectal surgery. Methods In this study, 37 patients were randomized to either the IVL group or the TEA group. IVL infusion was started before the surgical incision and stopped 30 minutes after transferring the patient to the postanesthesia care unit (PACU). Postoperative pain scores, opioid consumption, rescue analgesic doses, quality of recovery scores, time to discharge, and adverse events were recorded prospectively. Data were analyzed using two independent sample t-test and paired t-test, with p < 0.05 taken as statistically significant. Results The mean difference of overall NRS (numerical rating scale) pain scores in the ward was significantly higher in the IVL group as compared to the TEA group, which was 3.58 (2.29) vs 2.23 1.95) (p < 0.001). The IVL group required more mean rescue opioid boluses than the TEA group, which was 11.36 (8.684) vs 5.96 (6.215) (p < 0.001). However, both IVL and TEA groups had similar pain scores intraoperatively and in the PACU. Conclusions TEA provides better analgesia and decreased opioid requirements compared to intravenous lidocaine during the 24-hour period in the ward after laparoscopic left-sided colon and sphincter-sparing rectal surgery, although there was no difference in the quality of recovery between IVL and TEA groups.

Analgesic effect of oral ibuprofen 400, 600, and 800 mg; paracetamol 500 and 1000 mg; and paracetamol 1000 mg plus 60 mg codeine in acute postoperative pain: a single-dose, randomized, placebo-controlled, and double-blind study

PURPOSE

Effect size estimates of analgesic drugs can be misleading. Ibuprofen (400 mg, 600 mg, 800 mg), paracetamol (1000 mg, 500 mg), paracetamol 1000 mg/codeine 60 mg, and placebo were investigated to establish the multidimensional pharmacodynamic profiles of each drug on acute pain with calculated effect size estimates.

METHODS

A randomized, double-blind, single-dose, placebo-controlled, parallel-group, single-centre, outpatient, and single-dose study used 350 patients (mean age 25 year, range 18 to 30 years) of homogenous ethnicity after third molar surgery. Primary outcome was sum pain intensity over 6 h. Secondary outcomes were time to analgesic onset, duration of analgesia, time to rescue drug intake, number of patients taking rescue drug, sum pain intensity difference, maximum pain intensity difference, time to maximum pain intensity difference, number needed to treat values, adverse effects, overall drug assessment as patient-reported outcome measure (PROM), and the effect size estimates NNT and NNTp.

RESULTS

Ibuprofen doses above 400 mg do not significantly increase analgesic effect. Paracetamol has a very flat analgesic dose-response profile. Paracetamol 1000/codeine 60 mg gives similar analgesia as ibuprofen from 400 mg, but has a shorter time to analgesic onset. Active drugs show no significant difference in maximal analgesic effect. Other secondary outcomes support these findings. The frequencies of adverse effects were low, mild to moderate in all active groups. NNT and NTTp values did not coincide well with PROMs.

CONCLUSION

Ibuprofen doses above 400 mg for acute pain offer limited analgesic gain. Paracetamol 1000 mg/codeine 60 mg is comparable to ibuprofen doses from 400 mg. Calculated effect size estimates and PROM in our study seem not to relate well as clinical analgesic efficacy estimators.

TRIAL REGISTRATION

NCT00699114.

Regional anesthesia does not decrease inpatient or outpatient opioid demand in femoral shaft fracture surgery

INTRODUCTION

Regional anesthesia (RA) may be used in femoral shaft fracture surgery to decrease pain and opioid consumption. However, the impact of RA on inpatient and outpatient opioid demand in patients undergoing femoral shaft fracture surgery is largely unknown. The aim of this study was to evaluate the impact of RA on inpatient opioid consumption and outpatient opioid demand in patients undergoing femoral shaft fracture surgery.

METHODS

Inpatient opioid consumption and outpatient opioid demand in all patients undergoing femoral shaft fracture surgery was recorded at a single, Level I trauma center from 7/2013 - 7/2018 (n=436). In addition to RA, baseline and treatment factors including age, sex, race, body mass index (BMI), smoking, chronic opioid use, American Society of Anesthesiologists (ASA) score, injury mechanism, additional injuries, open injury, and additional inpatient surgery were recorded. Unadjusted and adjusted multivariable models were used to evaluate the impact of RA on inpatient opioid consumption and outpatient opioid demand.

RESULTS

Adjusted models demonstrated increases in inpatient opioid consumption in patients with RA (6.9 estimated OE's without RA vs 8.8 OE's with RA from 48-72 hours post-op, p<0.05) but no significant differences at other timepoints (10.3 estimated OE's without RA vs 9.2 OE's with RA from 0-24 hours post-op, 8.2 vs 8.8 from 24-48 hours post-op, p>0.05). Estimated cumulative outpatient opioid demand did not differ significantly in patients with RA (82.3 OE's without RA vs 94.8 with RA from discharge to two-weeks, 105.4 vs 116.3 OE's to 6-weeks, and 124.5 vs 137.9 OE's to 90-days, all p>0.05). Late opioid refills were significantly more common in patients with RA (1.57 odds at 2-weeks to 6-weeks, 1.69 odds at 6-weeks to 90-days, p<0.05) DISCUSSION: In femoral shaft fracture surgery, RA was not associated with decreased opioid demand after adjusting for baseline patient and treatment characteristics. These results provide a real-world estimate of the impact of RA on opioid demand in femoral shaft fracture surgery and encourage providers to seek alternative analgesic modalities.

LEVEL OF EVIDENCE

Level III, retrospective, therapeutic cohort study.

Regional anesthesia does not decrease opioid demand in pelvis and acetabulum fracture surgery

INTRODUCTION

Patients with pelvic and acetabular fractures often have considerable pain in the perioperative period. Regional anesthesia (RA) including peripheral nerve blocks and spinal analgesia may reduce pain. However, the real-world impact of these modalities on inpatient opioid consumption and outpatient opioid demand is largely unknown. The purpose of this study was to evaluate the impact of perioperative RA on inpatient opioid consumption and outpatient opioid demand.

METHODS

This is a retrospective, observational review of inpatient opioid consumption and outpatient opioid demand in all patients ages 18 and older undergoing operative fixation of pelvic and acetabular fractures at a single Level, I trauma center from 7/1/2013-7/1/2018 (n = 205). Unadjusted and adjusted analyses were constructed to evaluate the impact of RA on inpatient opioid consumption and outpatient opioid demand while controlling for age, sex, race, body mass index (BMI), smoking, chronic opioid use, ASA score, injury mechanism, additional injuries, open injury, and additional inpatient surgery.

RESULTS

Adjusted models demonstrated increases in inpatient opioid consumption in patients with RA (12.6 estimated OE's without RA vs 16.1 OE's with RA from 48 to 72 h post-op, p < 0.05) but no significant differences at other timepoints (17.5 estimated OE's without RA vs 16.8 OE's with RA from 0 to 24 h post-op, 15.3 vs 17.1 from 24 to 48 h post-op, p > 0.05). Estimated cumulative outpatient opioid demand was significantly higher in patients with RA at discharge to 90 days post-op (and 156.8 vs 207.9 OE's to 90 days, p < 0.05) but did not differ significantly before that time (121.5 OE's without RA vs 123.9 with RA from discharge to two weeks, 145.2 vs 177.2 OE's to 6 weeks, p > 0.05).

DISCUSSION

In pelvis and acetabulum fracture surgery, RA was associated with increased inpatient and outpatient opioid demand after adjusting for baseline patient and treatment characteristics. Regional anesthesia may not be beneficial for these patients.

Procedure-specific acute pain trajectory after elective total hip arthroplasty: systematic review and data synthesis

BACKGROUND

For most procedures, there is insufficient evidence to guide clinicians in the optimal timing of advanced analgesic methods, which should be based on the expected time course of acute postoperative pain severity and aimed at time points where basic analgesia has proven insufficient.

METHODS

We conducted a systematic search of the literature of analgesic trials for total hip arthroplasty (THA), extracting and pooling pain scores across studies, weighted for study size. Patients were grouped according to basic anaesthetic method used (general, spinal), and adjuvant analgesic interventions such as nerve blocks, local infiltration analgesia, and multimodal analgesia. Special consideration was given to high-risk populations such as chronic pain or opioid-dependent patients.

RESULTS

We identified and analysed 71 trials with 5973 patients and constructed pain trajectories from the available pain scores. In most patients undergoing THA under general anaesthesia on a basic analgesic regimen, postoperative acute pain recedes to a mild level (<4/10) by 4 h after surgery. We note substantial variability in pain intensity even in patients subjected to similar analgesic regimens. Chronic pain or opioid-dependent patients were most often actively excluded from studies, and never analysed separately.

CONCLUSIONS

We have demonstrated that it is feasible to construct procedure-specific pain curves to guide clinicians on the timing of advanced analgesic measures. Acute intense postoperative pain after THA should have resolved by 4-6 h after surgery in most patients. However, there is a substantial gap in knowledge on the management of patients with chronic pain and opioid-dependent patients.

Role of single-site and mini-laparoscopy in gynecologic surgery

INTRODUCTION

Laparoscopy is a surgical procedure that has been used widely in medicine over the last thirty years. In gynecology, laparoscopy is the "gold standard" for the majority of gynecological procedures, as its superiority over laparotomy has been widely demonstrated. In recent years, the current trend of gynecologists is to make laparoscopy surgery even less invasive by reducing the number of incisions in the skin, as it happens with laparoendoscopic single-site surgery, or by reducing the size of them as in mini-laparoscopy. The aim of this work was to perform an extensive review and update of the evolution of single-port surgery and mini-laparoscopic surgery in gynecology as well as to evaluate its current role in this field.

EVIDENCE ACQUISITION

A systematic review was performed during April and May 2020. PRISMA guidelines were followed for the literature search.

EVIDENCE SYNTHESIS

The main objective of performing less invasive procedures is to reduce both intraoperative complications (decreased risk of bleeding or damage to internal organs), and postoperative ones (hernias through the trocar) and improve cosmetic results. Results of studies about LESS and mini-LPS showed encouraging results, being both of them safe with a similar perioperative and postoperative outcome. They have the approval of the international surgical community as well as patients' satisfaction with cosmetic results.

CONCLUSIONS

Minimally invasive surgery is the present and future in gynecological surgery. More prospective randomized trials are needed in order to obtain valid results and affirm that both LESS and Mini-LPS are superior to conventional laparoscopy.

How Accurate Are the Surgical Risk Preoperative Assessment System (SURPAS) Universal Calculators in Total Joint Arthroplasty?

BACKGROUND

Surgical outcome prediction models are useful for many purposes, including informed consent, shared decision making, preoperative mitigation of modifiable risk, and risk-adjusted quality measures. The recently reported Surgical Risk Preoperative Assessment System (SURPAS) universal risk calculators were developed using 2005-2012 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP), and they demonstrated excellent overall and specialty-specific performance. However, surgeons must assess whether universal calculators are accurate for the small subset of procedures they perform. To our knowledge, SURPAS has not been tested in a subset of patients undergoing lower-extremity total joint arthroplasty (TJA).

QUESTIONS/PURPOSES

How accurate are SURPAS models' predictions for patients undergoing TJA?

METHODS

We identified an internal subset of patients undergoing non-emergency THA or TKA from the 2012 ACS-NSQIP, the most recent year of the SURPAS development dataset. To assess the accuracy of SURPAS prediction models, 30-day postoperative outcomes were defined as in the original SURPAS study: mortality, overall morbidity, and six complication clusters-pulmonary, infectious, cardiac or transfusion, renal, venous thromboembolic, and neurologic. We calculated predicted outcome probabilities by applying coefficients from the published SURPAS logistic regression models to the TJA cohort. Discrimination was assessed with C-indexes, and calibration was assessed with Hosmer-Lemeshow 10-group chi-square tests and decile plots.

RESULTS

The 30-day postoperative mortality rate for TJA was 0.1%, substantially lower than the 1% mortality rate in the SURPAS development dataset. The most common postoperative complications for TJA were intraoperative or postoperative transfusion (16%), urinary tract infection (5%), and vein thrombosis (3%). The C-indexes for joint arthroplasty ranged from 0.56 for venous thromboembolism (95% CI 0.53 to 0.59 versus SURPAS C-index 0.78) to 0.82 for mortality (95% CI 0.76 to 0.88 versus SURPAS C-index 0.94). All joint arthroplasty C-index estimates, including CIs, were lower than those reported in the original SURPAS development study. Decile plots and Hosmer-Lemeshow tests indicated poor calibration. Observed mortality rates were lower than expected for patients in all risk deciles (lowest decile: no observed deaths, 0.0% versus expected 0.1%; highest decile: observed mortality 0.7% versus expected 2%; p < 0.001). Conversely, observed morbidity rates were higher than expected across all risk deciles (lowest decile: observed 12% versus expected 8%; highest decile: observed morbidity 32% versus expected 25%; p < 0.001) CONCLUSIONS: The universal SURPAS risk models have lower accuracy for TJA procedures than they do for the wider range of procedures in which the SURPAS models were originally developed.

CLINICAL RELEVANCE

These results suggest that SURPAS model estimates must be evaluated for individual surgical procedures or within restricted groups of related procedures such as joint arthroplasty. Given substantial variation in patient populations and outcomes across numerous surgical procedures, universal perioperative risk calculators may not produce accurate and reliable results for specific procedures. Surgeons and healthcare administrators should use risk calculators developed and validated for specific procedures most relevant to each decision. Continued work is needed to assess the accuracy of universal risk calculators in more narrow procedural categories based on similarity of outcome event rates and prevalence of predictive variables across procedures.

Acute postoperative pain management

Background

Acute postoperative pain is common. Nearly 20 per cent of patients experience severe pain in the first 24 h after surgery, a figure that has remained largely unchanged in the past 30 years. This review aims to present key considerations for postoperative pain management.

Methods

A narrative review of postoperative pain strategies was undertaken. Searches of the Cochrane Library, PubMed and Google Scholar databases were performed using the terms postoperative care, psychological factor, pain management, acute pain service, analgesia, acute pain and pain assessment.

Results

Information on service provision, preoperative planning, pain assessment, and pharmacological and non-pharmacological strategies relevant to acute postoperative pain management in adults is presented, with a focus on enhanced recovery after surgery pathways.

Conclusion

Adequate perioperative pain management is integral to patient care and outcomes. Each of the biological, psychological and social dimensions of the pain experience should be considered and understood in order to provide optimum pain management in the postoperative setting.

Continuous local anaesthetic wound infusion for postoperative pain after midline laparotomy for colorectal resection in adults

BACKGROUND

Colorectal resection through a midline laparotomy is a commonly performed surgical procedure to treat various bowel conditions. The typical postoperative hospital stay after this operation is 6 to 10 days. The main factors hindering early recovery and discharge are thought to include postoperative pain and delayed return of bowel function.Continuous infusion of a local anaesthetic into tissues surrounding the surgical incision via a multi-lumen indwelling wound catheter placed by the surgeon prior to wound closure may reduce postoperative pain, opioid consumption, the time to return of bowel function, and the length of hospital stay.

OBJECTIVES

To evaluate the efficacy and adverse events of continuous local anaesthetic wound infusion for postoperative pain after midline laparotomy for colorectal resection in adults.

SEARCH METHODS

We searched the CENTRAL, MEDLINE and Embase databases to January 2019 to identify trials relevant to this review. We also searched reference lists of relevant trials and reviews for eligible trials. Additionally, we searched two clinical trials registers for ongoing trials.

SELECTION CRITERIA

We considered randomised controlled trials (including non-standard designs) or quasi-randomised controlled trials comparing continuous wound infusion of a local anaesthetic versus a placebo or a sham after midline laparotomy for colorectal resection in adults. We did not compare continuous local anaesthetic wound infusion to other techniques, such as transverse abdominis plane block or thoracic epidural analgesia. We allowed non-randomised analgesic co-interventions carried out equally in the intervention and control groups.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified trials for inclusion and assessed their quality using the Cochrane 'Risk of bias' tool. We extracted data using standardised forms, including pain at rest and on movement (10-point scale), opioid consumption via a patient-controlled analgesia (PCA) system (mg morphine equivalent), postoperative opioid-related adverse events, the time to rescue analgesia, the time to first flatus and to first bowel movement, the time to ambulation, the length of hospital stay, serious postoperative adverse events, and patient satisfaction. We quantitatively synthesised the data by meta-analysis. We summarised and graded the certainty of the evidence for critical outcomes using the GRADEpro tool and created a 'Summary of findings' table.

MAIN RESULTS

This review included six randomised controlled trials that enrolled a total of 564 adults undergoing elective midline laparotomy for colorectal resection comparing continuous wound infusion of a local anaesthetic to a normal saline placebo. Due to 23 post-randomisation exclusions, a total of 541 participants contributed data to the analysis of at least one outcome (local anaesthetic 268; control 273). Most participants were aged 55 to 65 years, with normal body mass index and low to moderate anaesthetic risk (American Society of Anesthesiologists class I-III). Random sequence generation, allocation concealment, and blinding were appropriately carried out in most trials. However, we had to downgrade the certainty of the evidence for most outcomes due to serious study limitations (risk of bias), inconsistency, indirectness, imprecision and reporting bias.Primary outcomesOn postoperative day 1, pain at rest (mean difference (MD) -0.59 (from 3.1), 95% confidence interval (CI) -1.12 to -0.07; 5 studies, 511 participants; high-certainty evidence), pain on movement (MD -1.1 (from 6.1), 95% CI -2.3 to -0.01; 3 studies, 407 participants; low-certainty evidence) and opioid consumption via PCA (MD -12 mg (from 41 mg), 95% CI -20 to -4; 6 studies, 528 participants; moderate-certainty evidence) were reduced in the local anaesthetic group compared to the control group.Secondary outcomesThere was a reduction in the time to first bowel movement (MD -0.67 from 4.4 days, 95% CI -1.17 to -0.17; 4 studies, 197 participants; moderate-certainty evidence) and the length of hospital stay (MD -1.2 from 7.4 days, 95% CI -2.0 to -0.3; 4 studies, 456 participants; high-certainty evidence) in the local anaesthetic group compared to the control group.There was no evidence of a difference in any serious postoperative adverse events until hospital discharge (RR 1.04, 95% CI 0.68 to 1.58; 6 studies, 541 participants; low-certainty evidence) between the two study groups.

AUTHORS' CONCLUSIONS

After elective midline laparotomy for colorectal resection, continuous wound infusion of a local anaesthetic compared to a normal saline placebo reduces postoperative pain at rest and the length of hospital stay, on the basis of high-certainty evidence. This means we are very confident that the effect estimates for these outcomes lie close to the true effects. There is moderate-certainty evidence to indicate that the intervention probably reduces opioid consumption via PCA and the time to first bowel movement. This means we are moderately confident that effect estimates for these outcomes are likely to be close to the true effects, but there is a possibility that they are substantially different. The intervention may reduce postoperative pain on movement, however, this conclusion is based on low-certainty evidence. This means our confidence in the effect estimate is limited. The true effect may be substantially different from the estimate of the effect. There is low-certainty evidence to indicate that the intervention may have little or no effect on the rates of any serious postoperative adverse events until hospital discharge. High-quality randomised controlled trials to evaluate the intervention with a focus on important clinical and patient-centred outcomes are needed.

The Effect of Perioperative Pregabalin on Pain after Arthroscopic Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial

Pain after anterior cruciate ligament (ACL) reconstruction is usually intense in the early postoperative period, but the efficacy of a multimodal analgesia approach remains controversial. This study aimed to investigate the analgesic efficacy of pregabalin in multimodal analgesia after ACL reconstruction. Patients who underwent ACL reconstruction under spinal anesthesia and agreed to use intravenous patient-controlled analgesia (IV-PCA) were randomly administered placebo (control group, n = 47) or pregabalin 150 mg (pregabalin group, n = 46) 1 h before surgery and 12 h after initial treatment. Pain by verbal numerical rating scale (VNRS) at rest and with passive flexion of knee was assessed at postoperative 12, 24, and 36 h and 2 weeks. IV-PCA consumption, rescue analgesic use, and side effects were also evaluated. Lower scores of VNRS were obtained with passive flexion of knee in the pregabalin group than in the control group at postoperative 24 (7(4-8) vs. 8(6-9), p = 0.043) and 36 h (4(3-7) vs. 5(4-9), p = 0.042), and lower value of VNRS at rest was observed in the pregabalin group [0(0-1)] than in the control group [1(0-2)] at postoperative 2 weeks (p < 0.001). No differences were obtained for IV-PCA consumption, rescue analgesic use, and side effects except for dizziness for postoperative 12 h. Pregabalin as an adjuvant to multimodal analgesic regimen significantly reduced early postoperative pain in patients undergoing ACL reconstruction.

Experience in the local use of 0.25% bupivacaine for the treatment of postoperative pain

According to British scientists, about 300 million operations are performed around the world annually. They cause acute postoperative pain, the management of which is crucial for improving patient outcomes and reducing healthcare costs. Local anesthetic infiltration before closing the surgical incision is a commonly used technique in the operating room. This review focuses on the use of local anesthetic infiltration, 0.25% bupivacaine, into surgical incisions to reduce postoperative pain, as confirmed by an estimate of a reduction in the use of postoperative opioids and a visual analogue scale (VAS). The presented clinical cases and the combined analgesia scheme with infiltration of a local anesthetic into the postoperative wound were used to make it possible to argue about the effectiveness of anesthesia because on the peripheral mechanism of pain. Infiltration analgesia reduced the need for opioids and the time of stay in hospitals. It was concluded that there is a need for further research on methods of delivering anesthetics to postoperative wounds for pain management and improving the quality of treatment.

Topical Analgesia with Lidocaine Plus Diclofenac Decreases Pain in Benign Anorectal Surgery: Randomized, Double-blind, and Controlled Clinical Trial

OBJECTIVE

The aim of this study is to evaluate the efficacy and safety of a topical formulation containing lidocaine plus diclofenac (CLIFE1) compared to lidocaine (CLIFE2), to decrease pain in benign anorectal surgery (BARS) to date not evaluated. More than 50% of patients undergoing BARS, especially hemorrhoidectomy, suffer from moderate and severe postoperative pain. This remains an unresolved problem that could be addressed with the new CLIFE1 topical treatment.

METHODS

A multicenter, randomized double-blind, active-controlled parallel-group superiority trial, was conducted in two Spanish hospitals. Patients undergoing BARS (hemorrhoids, anal fistula and anal fissure) were randomized at the end of surgery at a 1:1 ratio to receive first dose either CLIFE1 (n = 60) or CLIFE2 (n = 60) anorectal topical treatment, and after every 12 h for the first three postoperative days and once a day from the fourth to sixth. The primary outcome was average of pain decrease after topical treatment, measured with visual analogue scale (VAS) by the patients themselves, the evening in the surgery day and four times daily for the first three postoperative days.

RESULTS

The results of 120 patients included out of 150 selected undergoing BARS show a decrease in pain after CLIFE1 topical treatment (7.47 ± 13.09) greater than with CLIFE2 (4.38 ± 6.75), difference -3.21 95% CI (-5.75; -0.68), p = 0.008, decreasing significantly postoperative pain ( ≥ 9 mm, VAS) in 35% of patients undergoing benign anorectal surgery, compared to 18.33 % treated with lidocaine.

CONCLUSIONS

The CLIFE1 topical treatment shows better analgesic efficacy than CLIFE2 in BARS.

Procedure-Specific Pain Management (PROSPECT) - An update

Post-operative pain management protocols may be optimised by examining procedure-specific evidence and outcomes. This recognition led to the formation of the PROcedure-SPECific Pain ManagemenT (PROSPECT) collaboration of anaesthesiologists and surgeons. The aim of PROSPECT is to provide practical and evidence-based recommendations to prevent and treat post-operative pain after specific surgical procedures, thereby overcoming the limitations of generic, non-specific guidelines. Updates in the methodology of PROSPECT in 2017 have placed an increased emphasis on the clinical relevance of studies, including a focus on interventions in the context of multimodal analgesia strategies and consideration of risks and benefits of interventions in specific surgical settings. Evidence-based reviews of analgesic measures, including advice on surgical techniques and adjuvants after diverse surgical procedures, have been completed by the PROSPECT collaboration and are accessible on the website (www.postoppain.org) and published in the peer-reviewed literature. These reviews continue to identify significant gaps in clinically relevant research on post-operative analgesia and are possibly leading to a closing of some of these gaps.

Current methods and challenges for acute pain clinical trials

This article reviews current methods and challenges and provides recommendations for future design and conduct of clinical trials of interventions to treat acute pain.

Introduction:

The clinical setting of acute pain has provided some of the first approaches for the development of analgesic clinical trial methods.

Objectives:

This article reviews current methods and challenges and provides recommendations for future design and conduct of clinical trials of interventions to treat acute pain.

Conclusion:

Growing knowledge about important diverse patient factors as well as varying pain responses to different acute pain conditions and surgical procedures has highlighted several emerging needs for acute pain trials. These include development of early-phase trial designs that minimize variability and thereby enhance assay sensitivity, minimization of bias through blinding and randomization to treatment allocation, and measurement of clinically relevant outcomes such as movement-evoked pain. However, further improvements are needed, in particular for the development of trial methods that focus on treating complex patients at high risk of severe acute pain.

Postoperative pain-from mechanisms to treatment

INTRODUCTION

Pain management after surgery continues to be suboptimal; there are several reasons including lack of translation of results from basic science studies and scientific clinical evidence into clinical praxis.

OBJECTIVES

This review presents and discusses basic science findings and scientific evidence generated within the last 2 decades in the field of acute postoperative pain.

METHODS

In the first part of the review, we give an overview about studies that have investigated the pathophysiology of postoperative pain by using rodent models of incisional pain up to July 2016. The second focus of the review lies on treatment recommendations based on guidelines and clinical evidence, eg, by using the fourth edition of the "Acute Pain Management: Scientific Evidence" of the Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine.

RESULTS

Preclinical studies in rodent models characterized responses of primary afferent nociceptors and dorsal horn neurons as one neural basis for pain behavior including resting pain, hyperalgesia, movement-evoked pain or anxiety- and depression-like behaviors after surgery. Furthermore, the role of certain receptors, mediators, and neurotransmitters involved in peripheral and central sensitization after incision were identified; many of these are very specific, relate to some modalities only, and are unique for incisional pain. Future treatment should focus on these targets to develop therapeutic agents that are effective for the treatment of postoperative pain as well as have few side effects. Furthermore, basic science findings translate well into results from clinical studies. Scientific evidence is able to point towards useful (and less useful) elements of multimodal analgesia able to reduce opioid consumption, improve pain management, and enhance recovery.

CONCLUSION

Understanding basic mechanisms of postoperative pain to identify effective treatment strategies may improve patients' outcome after surgery.

Single dose intravenous paracetamol or intravenous propacetamol for postoperative pain

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 10, 2011. Paracetamol (acetaminophen) is the most commonly prescribed analgesic for the treatment of acute pain. It may be administered orally, rectally, or intravenously. The efficacy and safety of intravenous (IV) formulations of paracetamol, IV paracetamol, and IV propacetamol (a prodrug that is metabolized to paracetamol), compared with placebo and other analgesics, is unclear.

OBJECTIVES

To assess the efficacy and safety of IV formulations of paracetamol for the treatment of postoperative pain in both adults and children.

SEARCH METHODS

We ran the search for the previous review in May 2010. For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 1), MEDLINE (May 2010 to 16 February 2016), EMBASE (May 2010 to 16 February 2016), LILACS (2010 to 2016), a clinical trials registry, and reference lists of reviews for randomized controlled trials (RCTs) in any language and we retrieved articles.

SELECTION CRITERIA

Randomized, double-blind, placebo- or active-controlled single dose clinical trials of IV paracetamol or IV propacetamol for acute postoperative pain in adults or children.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data, which included demographic variables, type of surgery, interventions, efficacy, and adverse events. We contacted study authors for additional information. We graded each included study for methodological quality by assessing risk of bias and employed the GRADE approach to assess the overall quality of the evidence.

MAIN RESULTS

We included 75 studies (36 from the original review and 39 from our updated review) enrolling a total of 7200 participants.Among primary outcomes, 36% of participants receiving IV paracetamol/propacetamol experienced at least 50% pain relief over four hours compared with 16% of those receiving placebo (number needed to treat to benefit (NNT) = 5; 95% confidence interval (CI) 3.7 to 5.6, high quality evidence). The proportion of participants in IV paracetamol/propacetamol groups experiencing at least 50% pain relief diminished over six hours, as reflected in a higher NNT of 6 (4.6 to 7.1, moderate quality evidence). Mean pain intensity at four hours was similar when comparing IV paracetamol and placebo, but was seven points lower on a 0 to 100 visual analog scale (0 = no pain, 100 = worst pain imaginable, 95% CI -9 to -6, low quality evidence) in those receiving paracetamol at six hours.For secondary outcomes, participants receiving IV paracetamol/propacetamol required 26% less opioid over four hours and 16% less over six hours (moderate quality evidence) than those receiving placebo. However, this did not translate to a clinically meaningful reduction in opioid-induced adverse events.Meta-analysis of efficacy comparisons between IV paracetamol/propacetamol and active comparators (e.g., opioids or nonsteroidal anti-inflammatory drugs) were either not statistically significant, not clinically significant, or both.Adverse events occurred at similar rates with IV paracetamol or IV propacetamol and placebo. However, pain on infusion occurred more frequently in those receiving IV propacetamol versus placebo (23% versus 1%). Meta-analysis did not demonstrate clinically meaningful differences between IV paracetamol/propacetamol and active comparators for any adverse event.

AUTHORS' CONCLUSIONS

Since the last version of this review, we have found 39 new studies providing additional information. Most included studies evaluated adults only. We reanalyzed the data but the results did not substantially alter any of our previously published conclusions. This review provides high quality evidence that a single dose of either IV paracetamol or IV propacetamol provides around four hours of effective analgesia for about 36% of patients with acute postoperative pain. Low to very low quality evidence demonstrates that both formulations are associated with few adverse events, although patients receiving IV propacetamol have a higher incidence of pain on infusion than both placebo and IV paracetamol.

Effects of parecoxib on analgesia benefit and blood loss following open prostatectomy: a multicentre randomized trial

Background

This multi-centre, prospective, randomized, double-blind, placebo-controlled study was designed to test the hypotheses that parecoxib improves patients’ postoperative analgesia without increasing surgical blood loss following radical open prostatectomy.

Methods

105 patients (64 ± 7 years old) were randomized to receive either parecoxib or placebo with concurrent morphine patient controlled analgesia. Cumulative opioid consumption (primary objective) and the overall benefit of analgesia score (OBAS), the modified brief pain inventory short form (m-BPI-sf), the opioid-related symptom distress scale (OR-SDS), and perioperative blood loss (secondary objectives) were assessed.

Results

In each group 48 patients received the study medication for 48 hours postoperatively. Parecoxib significantly reduced cumulative opioid consumption by 24% (43 ± 24.1 mg versus 57 ± 28 mg, mean ± SD, p=0.02), translating into improved benefit of analgesia (OBAS: 2(0/4) versus 3(1/5.25), p=0.01), pain severity (m-BPI-sf: 1(1/2) versus 2(2/3), p < 0.01) and pain interference (m-BPI-sf: 1(0/1) versus 1(1/3), p=0.001), as well as reduced opioid-related side effects (OR-SDS score: 0.3(0.075/0.51) versus 0.4(0.2/0.83), p=0.03). Blood loss was significantly higher at 24 hours following surgery in the parecoxib group (4.3 g⋅dL⁻¹ (3.6/4.9) versus (3.2 g⋅dL⁻¹ (2.4/4.95), p=0.02).

Conclusions

Following major abdominal surgery, parecoxib significantly improves patients’ perceived analgesia. Parecoxib may however increase perioperative blood loss. Further trials are needed to evaluate the effects of selective cyclooxygenase-2 inhibitors on blood loss.

Trial registration

ClinicalTrials.gov Identifier: NCT00346268

Post-operative analgesic effects of paracetamol, NSAIDs, glucocorticoids, gabapentinoids and their combinations: a topical review

In contemporary post-operative pain management, patients are most often treated with combinations of non-opioid analgesics, to enhance pain relief and to reduce opioid requirements and opioid-related adverse effects. A diversity of combinations is currently employed in clinical practice, and no well-documented 'gold standards' exist. The aim of the present topical, narrative review is to provide an update of the evidence for post-operative analgesic efficacy with the most commonly used, systemic non-opioid drugs, paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs)/COX-2 antagonists, glucocorticoids, gabapentinoids, and combinations of these. The review is based on data from previous systematic reviews with meta-analyses, investigating effects of non-opioid analgesics on pain, opioid-requirements, and opioid-related adverse effects. Paracetamol, NSAIDs, COX-2 antagonists, and gabapentin reduced 24 h post-operative morphine requirements with 6.3 (95% confidence interval: 3.7 to 9.0) mg, 10.2 (8.7, 11.7) mg, 10.9 (9.1, 12.8) mg, and ≥ 13 mg, respectively, when administered as monotherapy. The opioid-sparing effect of glucocorticoids was less convincing, 2.33 (0.26, 4.39) mg morphine/24 h. Trials of pregabalin > 300 mg/day indicated a morphine-sparing effect of 13.4 (4, 22.8) mg morphine/24 h. Notably, though, the available evidence for additive or synergistic effects of most combination regimens was sparse or lacking. Paracetamol, NSAIDs, selective COX-2 antagonists, and gabapentin all seem to have well-documented, clinically relevant analgesic properties. The analgesic effects of glucocorticoids and pregabalin await further clarification. Combination regimens are sparsely documented and should be further investigated in future studies.

[Oral therapy algorithm for the treatment of postoperative pain. A prospective observational study]

BACKGROUND

Postoperative pain continues to be undermanaged, at least in part, due to inadequate organization and lack of use of opioids. Especially patients who do not receive consultation from an acute pain service and are therefore not eligible to receive regional anesthesia techniques or patient-controlled devices suffer from severe pain after surgery. The aim of the present prospective observational study was to assess the efficacy and feasibility of an analgesia algorithm for this subgroup of patients.

METHODS

An oral opioid concept including controlled-release (cr) oxycodone, immediate-release (ir) hydromorphone and a non-opioid analgesic was implemented at three different departments at the University Clinic of Muenster, Germany. Briefly, cr-oxycodon was administered preoperatively to patients undergoing ear nose and throat (ENT), general or elective trauma surgery on the day of surgery and every 12 h for a maximum of 4 days postoperatively. Inadequately managed pain above 3 on a visual analog scale (VAS 0-10) at rest and above 5 during movement was treated with ir-hydromorphone on patient request. After written informed consent, patients were assessed prospectively for up to 5 days perioperatively using a standardized questionnaire preoperatively, for 4 days postoperatively as well as 6 and 12 months after surgery.

RESULTS

A total of 275 patients were included in the present prospective observational study: (ENT surgery: 163, trauma surgery 82 and general surgery 30). Median resting and evoked numeric rating scale (NRS) pain scores were equal or less than 3 and 5, respectively. Less patients received cr-oxycodone after ENT and general surgery compared to trauma surgery (p < 0.001). Constipation was more frequent after general and trauma surgery compared to ENT surgery. Vomiting decreased from 20 %-30 % on the day of surgery to 10 % or less regardless of the type of operation. No severe adverse events were observed. Additionally, patients with an increased depression score before surgery reported greater immediate postoperative pain than non-depressed patients. Of the patients 11 (15.7 %) and 7 (14.9 %) complained about persistent postoperative pain 6 and 12 months after surgery, respectively and these patients had increased acute pain ratings during the first postoperative days.

CONCLUSIONS

The present study has demonstrated that the implementation of an oral opioid algorithm for patients without patient-controlled intravenous or regional analgesia is effective and feasible on surgical wards. Patients who underwent trauma surgery needed more cr-oxycodone. Side effects were similar regardless of the operation with the exception of obstipation which was more frequent after trauma and general surgery compared to ENT surgery.

Heterogeneity in meta-analyses of treatment of acute postoperative pain: a review

BACKGROUND

Heterogeneity and its causes must be assessed using meta-analyses (meta-analysis). Especially in meta-analysis dealing with treatment of acute postoperative pain, the type of surgery is a source of heterogeneity. We aimed to assess whether the type of surgery is considered a source of heterogeneity in meta-analysis and how it is taken into account in meta-analysis evaluating the efficacy of treatment of acute postoperative pain. We further compared meta-analysis that pooled trials of surgeries with highly heterogeneous postoperative pain levels, the heterogeneous group, with meta-analysis that pooled trials involving surgeries with homogeneous pain levels, the homogenous group.

METHODS

The meta-analysis reports available in Issue 3, 2011 of the electronic database of the Cochrane library and pooling results of randomized or quasi-randomized controlled trials that assessed the efficacy of treatment of acute postoperative pain alone were considered. A survey of experts established a rating of the postoperative pain levels for the type of surgery. For each meta-analysis, the different pain level ratings associated with the trials included in the meta-analysis were considered and the standard deviation (sd) of these ratings calculated. From the distribution of sd values, we defined the heterogeneous and homogeneous groups.

RESULTS

Sixty-one meta-analyses were included; all assessed heterogeneity. Twenty-six meta-analyses considered the type of surgery as a subgroup (50% vs 38% in the homogeneous group vs heterogeneous group). Forty-four reports discussed the type of surgery as a source of clinical heterogeneity (85% vs 62% for the homogeneous vs heterogeneous group). Twenty-nine meta-analyses compared 'postoperative pain from dental surgery' to 'other type of surgery'.

CONCLUSIONS

Meta-analyses evaluating treatment of postoperative pain should explore clinical heterogeneity associated with the type of surgery for better implications for practice.

[Perioperative pain therapy]

Scientific studies have proven without doubt that an optimized perioperative pain therapy will improve patient comfort, reduce postoperative complications, enhance postoperative recovery and shorten the length of postoperative hospital stay. It is necessary to incorporate the acute pain therapy into a perioperative multimodal and interdisciplinary therapeutic concept. Local or regional anesthesia will provide the best analgesic effect after surgery and should be considered in all patients. Optimal treatment of patients with peripheral nerve blocks, spinal or epidural analgesia should be treated by a specialized acute pain service. However, only 15-20% of all surgical cases will be taken care of by such a pain service. Therefore, most surgical patients will only receive adequate analgesia if surgeons are familiar with the principles of postoperative pain therapy. Regular assessment of pain perception is the cornerstone of optimized pain therapy. Furthermore, pain assessment will allow the administration and to some extent dosage of analgesic therapy to be delegated to nursing personnel.

Single dose intravenous propacetamol or intravenous paracetamol for postoperative pain

BACKGROUND

Paracetamol (acetaminophen) is the most commonly prescribed analgesic for the treatment of acute pain. It may be administered orally or intravenously. The efficacy and safety of intravenous (IV) formulations of paracetamol, IV paracetamol and IV propacetamol, compared with placebo and other analgesics, is unclear.

OBJECTIVES

To assess the efficacy and safety of IV formulations of paracetamol for treatment of postoperative pain in both adults and children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), MEDLINE (1950 to May 2010), EMBASE (1980 to 2010, Week 18), LILACS (1992 to May 2010) and reference lists of retrieved articles.

SELECTION CRITERIA

Randomized, double-blind, placebo- or active-controlled single dose clinical trials of IV propacetamol or IV paracetamol for acute postoperative pain in adults or children.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and extracted data. We contacted study authors for additional information. We collected adverse event information from the studies.

MAIN RESULTS

Thirty-six studies (3896 participants) were included. Thirty-seven percent of participants receiving IV propacetamol/paracetamol experienced at least 50% pain relief over four hours compared with 16% of those receiving placebo (number needed to treat to benefit (NNT = 4.0; 95% confidence interval 3.5 to 4.8). The proportion of participants in IV propacetamol/paracetamol groups experiencing at least 50% pain relief diminished over six hours, as reflected in a higher NNT of 5.3 (4.2 to 6.7). Participants receiving IV propacetamol/paracetamol required 30% less opioid over four hours than those receiving placebo. However, this did not translate to a reduction in opioid-induced adverse events.Meta-analysis of efficacy comparisons between IV propacetamol/paracetamol and active comparators (opioids or nonsteroidal anti-inflammatories (NSAIDs)) were either not statistically significant, not clinically significant, or both.Adverse events occurred at similar rates with IV propacetamol or IV paracetamol and placebo. However, pain on infusion occurred more frequently in those receiving IV propacetamol versus placebo (23% versus 1%).Meta-analysis did not demonstrate statistically significant differences between IV propacetamol/paracetamol and active comparators for any adverse event except a reduction in the rate of hypotension versus NSAIDs and a reduction in the rate of gastrointestinal disorders versus opioids.

AUTHORS' CONCLUSIONS

A single dose of both IV propacetamol and IV paracetamol provides around four hours of effective analgesia for about 37% of patients with acute postoperative pain. Both formulations are associated with few adverse events, although patients receiving IV propacetamol have a higher incidence of pain on infusion than both placebo and IV paracetamol.

Continuous multimechanistic postoperative analgesia: a rationale for transitioning from intravenous acetaminophen and opioids to oral formulations

Good surgical outcomes depend in part on good pain relief, allowing for early mobilization, optimal recovery, and patient satisfaction. Postsurgical pain has multiple mechanisms, and multimechanistic approaches to postoperative analgesia are recommended and may be associated with improved pain relief, lowered opioid doses, and sometimes a lower rate of opioid-associated side effects. Acetaminophen (paracetamol) is a familiar agent for treating many types of pain, including postsurgical pain. Oral acetaminophen has been shown to be safe and effective in a variety of acute pain models. Combination products using a fixed-dose of acetaminophen and an opioid have also been effective in treating postsurgical pain. Combination products with acetaminophen have demonstrated an opioid-sparing effect, which inconsistently results in a reduced rate of opioid-associated side effects. Intravenous (IV) acetaminophen and an opioid analgesic administered in the perioperative period may be followed by an oral acetaminophen and opioid combination in the postoperative period. Transitioning from an IV acetaminophen and opioid formulation to a similar but oral formulation of the same drugs appears to be a reasonable step in that both analgesic therapies are known to be safe and effective. For postsurgical analgesia with any acetaminophen product, patient education is necessary to be sure that the patient does not concurrently take any over-the-counter products containing acetaminophen and accidentally exceed dose limits.

Single-dose intravenous paracetamol or propacetamol for prevention or treatment of postoperative pain: a systematic review and meta-analysis

Paracetamol is the most commonly prescribed analgesic for the treatment of acute pain. The efficacy and safety of i.v. formulations of paracetamol is unclear. We performed a systematic search (multiple databases, bibliographies, any language, to May 2010) for single-dose, randomized, controlled clinical trials of propacetamol or i.v. paracetamol for acute postoperative pain in adults or children. Thirty-six studies involving 3896 patients were included. For the primary outcome, 37% of patients (240/367) receiving propacetamol or i.v. paracetamol experienced at least 50% pain relief over 4 h compared with 16% (68/527) receiving placebo (number needed to treat=4.0; 95% confidence interval, 3.5-4.8). The proportion of patients in propacetamol or i.v. paracetamol groups experiencing at least 50% pain relief diminished over 6 h. Patients receiving propacetamol or paracetamol required 30% less opioid over 4 h and 16% less opioid over 6 h than those receiving placebo. However, this did not translate to a reduction in opioid-induced adverse events (AEs). Similar comparisons between propacetamol or i.v. paracetamol and active comparators were either not statistically significant, not clinically significant, or both. AEs occurred at similar rates with propacetamol or i.v. paracetamol and placebo. However, pain on infusion occurred more frequently in those receiving propacetamol compared with placebo (23% vs 1%). A single dose of either propacetamol or i.v. paracetamol provides around 4 h of effective analgesia for about 37% of patients with acute postoperative pain. Both formulations are associated with few AEs, although patients receiving propacetamol have a higher incidence of pain on infusion.

Paracetamol reduces postoperative pain and rescue analgesic demand after robot-assisted endoscopic thyroidectomy by the transaxillary approach

BACKGROUND

Postoperative pain following endoscopic thyroidectomy, although less severe than after open methods, is still a source of marked discomfort and surgical stress. This clinical trial was conducted to determine if repeated intravenous paracetamol could decrease postoperative pain and rescue analgesic requirements after robot-assisted endoscopic thyroidectomy via the transaxillary approach.

MATERIALS AND METHODS

This prospective, randomized, double-blinded, and placebo-controlled study enrolled 124 women 21-60 years of age who were scheduled for elective gasless robot-assisted endoscopic thyroidectomy via the transaxillary approach. The patients were given placebo or 1 g of paracetamol as a 100 ml solution infused over 15 min 1 h before the induction of anesthesia, and then at 6-h intervals for the following 24 h.

RESULTS

Postoperative pain scores were significantly lower at 1, 3, 6, and 24 h after surgery in the paracetamol group than in the placebo group. Significantly fewer patients in the paracetamol group received rescue analgesics compared to the placebo group (9.5% vs. 65.6%, respectively). First analgesic time was similar in the two groups. Postoperative nausea (44.3% vs. 22.2%) and vomiting (21.3% vs. 6.3%) were more frequent in the placebo group than in the paracetamol group. Other postoperative side effects, including sedation, confusion, and pruritus, were similar in the two groups.

CONCLUSIONS

We concluded that repeated administration of 1 g of intravenous paracetamol over 24 h is easy, effective, safe, and well tolerated for pain management in patients with moderate to severe postoperative pain after gasless robot-assisted endoscopic thyroidectomy performed via the transaxillary approach.

[Concepts for perioperative pain therapy. A critical stocktaking]

Despite numerous publications, new guidelines for the treatment of acute pain and efforts from a number of initiatives, there is still a tremendous need for improvement in postoperative pain therapy. One of the reasons for the shortcomings in the care of patients with postoperative pain is the lack of applicability of guidelines in daily clinical practice. Therefore, simple but effective and easy to implement concepts need to be developed. In the following review, different concepts that have been developed over recent years are presented and evaluated for their effectiveness. One of these is the notion of balanced analgesia, currently probably one of the most widely used perioperative therapy concepts. The idea of this concept is to reduce the doses of analgesics, e.g. opioids, through combinations of different classes of analgesics, thereby reducing their side effects. However, recent studies and essential meta-analyses indicate pitfalls using this concept. The pros and cons will be discussed and ideas on how to deal with balanced analgesia in daily practice will be given. Another pain concept of "procedure-specific postoperative pain therapy", is an appealing idea of an international initiative from surgeons and anaesthesiologists and an essential part of the German S3 guidelines for acute pain released last year. Critical evaluation of the available recommendations for procedure-specific analgesia together with the presentation of relatively simple but evidence-based algorithms for specific procedures may help to implement this concept in clinical routine.

Consensus statement on the anticipation and prevention of acute postoperative pain: multidisciplinary RADAR approach

BACKGROUND

There has been considerable investment in efforts to improve postoperative pain management, including the introduction of acute pain teams. There have also been a number of guidelines published on postoperative pain management and there is widespread agreement on how pain should be practically managed. Despite these advances, there is no apparent improvement in the number of patients experiencing moderately severe or extreme pain after surgery. This highlights significant scope for improvement in acute postoperative pain management.

SCOPE

In January 2009, a multidisciplinary UK expert panel met to define and agree a practical framework to encourage implementation of the numerous guidelines and fundamentals of pain management at a local level. The panel recognised that to do this, there was a need to organise the information and guidelines into a simplified, accessible and easy-to-implement system based on their practical clinical experience. Given the volume of literature in this area, the Chair recommended that key international guidelines from professional bodies should be distributed and then reviewed during the meeting to form the basis of the framework. Consensus was reached by unanimous agreement of all ten participants.

FINDINGS

This report provides a framework for the key themes, including consensus recommendations based upon practical experience agreed during the meeting, with the aim of consolidating the key guidelines to provide a fundamental framework which is simple to teach and implement in all areas. Key priorities that emerged were: Responsibility, Anticipation, Discussion, Assessment and Response. This formed the basis of RADAR, a novel framework to help pain specialists educate the wider care team on understanding and prioritising the management of acute pain.

CONCLUSION

Acute postoperative pain can be more effectively managed if it is prioritised and anticipated by a well-informed care team who are educated with regard to appropriate analgesic options and understand what the long-term benefits of pain relief are. The principles of RADAR provide structure to help with training and implementation of good practice, to achieve effective postoperative pain management.