Local infusion of bupivacaine combined with intravenous patient-controlled analgesia provides better pain relief than intravenous patient-controlled analgesia alone in patients undergoing minimally invasive cardiac surgery

Peripheral Regional Anesthetic Techniques in Cardiac Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this systematic review was to investigate postoperative pain outcomes and adverse events after peripheral regional anesthesia (PRA) compared to no regional anesthesia (RA), placebo, or neuraxial anesthesia in children and adults undergoing cardiac surgery.

DESIGN

A systematic review and meta-analysis with an assessment of the risk of bias (Cochrane RoB 1) and certainty of evidence (Grading of Recommendations, Assessment, Development, and Evaluation).

SETTING

Randomized controlled trials (RCTs).

PARTICIPANTS

Adults and children undergoing heart surgery.

INTERVENTIONS

Any kind of PRA compared to no RA or placebo or neuraxial anesthesia.

MEASUREMENTS AND MAIN RESULTS

In total, 33 RCTs (2,044 patients) were included-24 of these had a high risk of bias, and 28 were performed in adults. Compared to no RA, PRA may reduce pain intensity at rest 24 hours after surgery (mean difference [MD] -0.81 points, 95% CI -1.51 to -0.10; I2 = 92%; very low certainty evidence). Peripheral regional anesthesia, compared to placebo, may reduce pain intensity at rest (MD -1.36 points, 95% CI -1.59 to -1.13; I2 = 54%; very low certainty evidence) and during movement (MD -1.00 points, 95% CI -1.34 to -0.67; I² = 72%; very low certainty evidence) 24 hours after surgery. No data after pediatric cardiac surgery could be meta-analyzed due to the low number of included trials.

CONCLUSIONS

Compared to no RA or placebo, PRA may reduce pain intensity at rest and during movement. However, these results should be interpreted cautiously because the certainty of evidence is only very low.

Practice Advisory for Preoperative and Intraoperative Pain Management of Cardiac Surgical Patients: Part 2

Pain after cardiac surgery is of moderate to severe intensity, which increases postoperative distress and health care costs, and affects functional recovery. Opioids have been central agents in treating pain after cardiac surgery for decades. The use of multimodal analgesic strategies can promote effective postoperative pain control and help mitigate opioid exposure. This Practice Advisory is part of a series developed by the Society of Cardiovascular Anesthesiologists (SCA) Quality, Safety, and Leadership (QSL) Committee's Opioid Working Group. It is a systematic review of existing literature for various interventions related to the preoperative and intraoperative pain management of cardiac surgical patients. This Practice Advisory provides recommendations for providers caring for patients undergoing cardiac surgery. This entails developing customized pain management strategies for patients, including preoperative patient evaluation, pain management, and opioid use-focused education as well as perioperative use of multimodal analgesics and regional techniques for various cardiac surgical procedures. The literature related to this field is emerging, and future studies will provide additional guidance on ways to improve clinically meaningful patient outcomes.

Sternotomy Wound Infiltration With Liposomal Versus Plain Bupivacaine for Postoperative Analgesia After Elective Cardiac Surgery

OBJECTIVES

Poor pain control after cardiac surgery can be associated with postoperative complications, longer recovery, and development of chronic pain. The authors hypothesized that adding liposomal bupivacaine (LB) to plain bupivacaine (PB) will provide better and long-lasting analgesia when used for wound infiltration in median sternotomy.

STUDY DESIGN

Prospective, randomized, and double-blinded clinical trial.

SETTING

Single institution, tertiary care university hospital.

PARTICIPANTS

Adult patients who underwent elective cardiac surgery through median sternotomy.

INTERVENTIONS

A single surgeon performed wound infiltration of LB plus PB or PB into the sternotomy wound, chest, and mediastinal tube sites.

MEASUREMENTS AND MAIN RESULTS

Patients were followed up for 72 hours for pain scores, opioid consumption, and adverse events. Sixty patients completed the study for analysis (LB group [n = 29], PB group [n = 31]). Patient characteristics, procedural variables, and pain scores measured at specific intervals from 4 hours until 72 hours postoperatively did not reveal any significant differences between the groups. Mixed-model regression showed that the trend of mean pain scores at movement in the LB group was significantly (p = 0.01) lower compared with the PB group. Opioid consumption over 72 hours was not significantly different between the 2 groups (oral morphine equivalents; median [interquartile range], 139 [73, 212] mg in LB v 105 [54, 188] mg in PB, p = 0.29). Recovery characteristics and adverse events were comparable.

CONCLUSIONS

LB added to PB for sternotomy wound infiltration during elective cardiac surgery did not significantly improve the quality of postoperative analgesia.

Median sternotomy pain after cardiac surgery: To block, or not? A systematic review and meta-analysis

BACKGROUND

Inadequate pain control after median sternotomy leads to reduced mobilization, increased respiratory complications, and longer hospital stays. Typically, postoperative pain is controlled by opioid analgesics that may have several adverse effects. Parasternal intercostal block (PSB) has emerged as part of a multimodal strategy to control pain after median sternotomy. However, the effectiveness of this intervention on postoperative pain control and analgesic use has not been fully established.

METHODS AND RESULTS

We conducted a meta-analysis to assess the effect of PSB on postoperative pain and analgesic use in adult cardiac surgery patients undergoing median sternotomy. PubMed, Embase, Google Scholar, and the Cochrane database were searched with the following search strategy: ([postoperative pain] or [pain relief] OR [analgesics] or [analgesia] or [nerve block] or [regional block] or [local block] or [regional anesthesia] or [local anesthetic] or [parasternal block] and [sternotomy]) and (humans [filter]). Inclusion criteria were: patients who underwent cardiac surgery via median sternotomy, age >18 and parasternal block (continuous and single dose). Exclusion criteria were: noncardiac surgery, nonparasternal nerve blocks, and the use of NSAIDS in parasternal block. Quality assessment was performed by three independent reviewers via the Cochrane risk of bias assessment tool. Of 1165 total citations, 18 were found to be relevant. Of these 18 citations, 7 citations (N = 2223 patients) reported postoperative pain scores in an extractable format and 11 citations (N = 2155 patients) reported postoperative opioid use in an extractable format. For postoperative opioid use, morphine equivalent doses were calculated for all studies and postoperative pain scores were standardized to a 10-point visual analog scale for comparison between studies; both these were reported as total opioid use or cumulative score ranging from 24 to 72 h postoperative. All data analyses were run using a random effects model, using a restricted maximum likelihood estimator, to obtain summary standardized mean differences with 95% confidence interval (CI's). For studies which only reported median and interquatile range (IQR), the median was standard deviation was estimated by IQR/1.35. Following median sternotomy both postoperative pain (SMD [95% CI] -0.49 [-0.92 to -0.06]) and postoperative morphine equivalent use (SMD [95% CI] -1.68 [-3.11 to -0.25]) were significantly less in the PSB group.

CONCLUSION

Our meta-analysis suggests that parasternal nerve block significantly reduces postoperative pain and opioid use.

Evaluation of Different Pain-Control Procedures for Post-cardiac Surgery: A Systematic Review and Network Meta-Analysis

Objective

To identify superior pain-control procedures for postoperative patients who undergo cardiac surgeries.

Methods

Literature searches were conducted in globally recognized databases, including MEDLINE, EMBASE and Cochrane Central, to identify randomized controlled trials (RCTs) investigating pain-control procedures after cardiac surgeries. The parameters evaluating analgesic efficacy and postoperative recovery, namely, the pain score and ICU stay, were quantitatively pooled and estimated using Bayesian methods. The values of the surface under the cumulative ranking (SUCRA) probabilities regarding each parameter were calculated to enable the ranking of various pain-control procedures. Node-splitting analysis was performed to test the inconsistency of the main results, and the publication bias was assessed by examining the funnel-plot symmetry.

Results

After a detailed review, 13 RCTs containing 7 different procedures were included in the network meta-analysis. After pooling the results together, an erector spinae plane block (ESPB) and a local parasternal block (LPB) plus target-controlled infusion (TCI) presented the best analgesic effects for reducing pain at rest (SUCRA, .47) and during movement (SUCRA, .52), respectively, while the former also achieved the shortest ICU stay (SUCRA, .48). Moreover, the funnel-plot symmetries showed no inconsistencies or obvious publication bias in the current study.

Conclusions

The current evidence indicates that ESPB is a potential superior analgesic strategy for post-cardiac surgery patients. To verify this conclusion further, it is imperative to obtain more high-quality evidence and conduct relevant investigations in the future.

Updates on Wound Infiltration Use for Postoperative Pain Management: A Narrative Review

Local anesthetic wound infiltration (WI) provides anesthesia for minor surgical procedures and improves postoperative analgesia as part of multimodal analgesia after general or regional anesthesia. Although pre-incisional block is preferable, in practice WI is usually done at the end of surgery. WI performed as a continuous modality reduces analgesics, prolongs the duration of analgesia, and enhances the patient’s mobilization in some cases. WI benefits are documented in open abdominal surgeries (Caesarean section, colorectal surgery, abdominal hysterectomy, herniorrhaphy), laparoscopic cholecystectomy, oncological breast surgeries, laminectomy, hallux valgus surgery, and radical prostatectomy. Surgical site infiltration requires knowledge of anatomy and the pain origin for a procedure, systematic extensive infiltration of local anesthetic in various tissue planes under direct visualization before wound closure or subcutaneously along the incision. Because the incidence of local anesthetic systemic toxicity is 11% after subcutaneous WI, appropriate local anesthetic dosing is crucial. The risk of wound infection is related to the infection incidence after each particular surgery. For WI to fully meet patient and physician expectations, mastery of the technique, patient education, appropriate local anesthetic dosing and management of the surgical wound with “aseptic, non-touch” technique are needed.

Bupivacaine infiltration for acute postoperative pain management after cardiac surgery

BACKGROUND

Despite increased attention, acute and persistent post-operative pain are not treated efficiently and interventions against acute pain are therefore of clinical importance and should be welcomed.

AIMS AND OBJECTIVES

To evaluate the effectiveness of wound infiltration with 0.5% bupivacaine for pain management in the immediate post-operative period in patients that underwent cardiac surgery with sternotomy.

DESIGN

The study was performed employing a single-centre nonrandomized experimental design to evaluate a prospective cohort of patients recruited from June to December of 2017.

METHODS

A single-centre study with a non-randomized experimental design compared the pain perceived by 137 patients undergoing to cardiac surgery within which 68 patients who received infiltration of bupivacaine and 69 patients received infiltration with saline solution. Pain measures were made with the numeric rating scale (NRS) at 2, 12, 24, and 48 hours. Socio-demographic and clinical variables were included too and descriptive, bivariate, and multivariate logistic regression analyses were performed.

RESULTS

A statistically significant difference was found between the means of the NRS scores in favour of the intervention group. Cohen's d showed a significant effect size. NRS scores were grouped into NRS ≥4 or NRS <4 and similar results were found. Multivariate logistic regression analyses showed the absence of confounding factors that could call results into question.

CONCLUSION

Subcutaneous infiltration of 0.5% bupivacaine in the surgical site of patients who have undergone cardiac surgery showed clinically and statistically significant pain relief compared with patients who received saline infiltration throughout the first 12 hours after surgery. This intervention provides promising preliminary results that, alone or in conjunction with other nursing interventions, could constitute an important therapeutic tool for this area of nursing clinical practice.

Post-Cardiotomy Parasternal Nerve Block with Bupivacaine may be Associated with Reduced Post-Operative Opioid Use in Children: A Retrospective Cohort Study

Postoperative pain treatment affects immediate and long-term outcomes in children undergoing cardiac surgery. Opioids, as part of multimodal analgesia, are effective in treating pain, however, they can be disadvantageous due to adverse side effects. Therefore, we assessed whether the local anesthetic bupivacaine as a parasternal nerve block in children post-cardiac surgery is an effective adjunct to pain management. This was a retrospective cohort study of all patients who underwent cardiothoracic surgery via median sternotomy at a large children’s hospital between November 2011 and February 2014 with and without bupivacaine following the introduction of perioperative bupivacaine in late 2012 on a single unit. 62 out of 148 patients (age 3–17 years) who received bupivacaine demonstrated decreased postoperative opioid use. Within one day of surgery, patients who received bupivacaine required, on average, 0.57 mg/kg (95% CI, 0.46 to 0.68) of total morphine equivalent compared to 0.93 mg/kg (95% CI, 0.80 to 1.06) for patients who did not receive bupivacaine. This difference was statistically significant after adjusting for potential confounders (p-value = 0.002). Length of stay and intubation were shorter on average among patients who received bupivacaine, but these differences were not statistically significant after adjusting for potential confounders. The study results seem to suggest that the perioperative administration of bupivacaine may reduce opioid usage among children post-cardiotomy.

Fifty Percent Reduction in Narcotic Use After Minimally Invasive Cardiac Surgery Using Liposomal Bupivacaine

Objective

Minimally invasive cardiac surgery via a right minithoracotomy (RMT) is a common approach to different valve pathologies, tumor resection, and atrial septal defect (ASD) closure. We studied intraoperative field block using liposomal bupivacaine (LB) in these operations.

Methods

Consecutive 171 minimally invasive RMTs (fourth intercostal space) were studied, and patients in cardiogenic or septic shock, intravenous drug abuse, and those re-explored were excluded ( n = 12). An early cohort was treated with standard postoperative analgesia while another underwent intraoperative field block with LB immediately after incision. We compared postoperative pain level, narcotic utilization (morphine milligram equivalent), and intensive care unit (ICU) and hospital length of stay.

Results

The procedures included 48 isolated mitral valve replacements (MVR); 2 MVR with other procedures; 93 mitral valve repairs (MVRr); 9 MVRr with other procedures; 4 isolated tricuspid valve repairs; 2 myxoma resections; 1 ASD closure. There were 13 patients in the non-LB group and 146 patients in the LB group. Use of LB decreased mean postoperative narcotic utilization by 50% ( P = 0.003). The LB group had lower pain levels on postoperative day 1 ( P = 0.039), which continued through postoperative day 5 ( P = 0.030). We found no difference in ICU or hospital length of stay between groups. There were no complications from LB field block.

Conclusions

LB field block decreases postoperative pain and narcotic utilization after cardiac surgery via a RMT, but it does not reduce length of stay. The technique is safe and should be considered in all patients undergoing RMT cardiac surgery.

The efficacy of different modes of analgesia in postoperative pain management and early mobilization in postoperative cardiac surgical patients: A systematic review

Cardiac surgery induces severe postoperative pain and impairment of pulmonary function, increases the length of stay (LOS) in hospital, and increases mortality and morbidity; therefore, evaluation of the evidence is needed to assess the comparative benefits of different techniques of pain management, to guide clinical practice, and to identify areas of further research. A systematic search of the Cochrane Central Register of Controlled Trials, DARE database, Joanna Briggs Institute, Google scholar, PUBMED, MEDLINE, EMBASE, Academic OneFile, SCOPUS, and Academic search premier was conducted retrieving 1875 articles. This was for pain management postcardiac surgery in intensive care. Four hundred and seventy-one article titles and 266 abstracts screened, 52 full text articles retrieved for critical appraisal, and ten studies were included including 511 patients. Postoperative pain (patient reported), complications, and LOS in intensive care and the hospital were evaluated. Anesthetic infiltrations and intercostal or parasternal blocks are recommended the immediate postoperative period (4-6 h), and patient-controlled analgesia (PCA) and local subcutaneous anesthetic infusions are recommended immediate postoperative and 24-72 h postcardiac surgery. However, the use of mixed techniques, that is, PCA with opioids and local anesthetic subcutaneous infusions might be the way to go in pain management postcardiac surgery to avoid oversedation and severe nausea and vomiting from the narcotics. Adequate studies in the use of ketamine for pain management postcardiac surgery need to be done and it should be used cautiously.

The effect of local anesthetic continuous wound infusion for the prevention of postoperative pneumonia after on-pump cardiac surgery with sternotomy: the STERNOCAT randomized clinical trial

PURPOSE

Postoperative pain after cardiac surgery, exacerbated by cough and sternal mobilization, limits clearance of bronchopulmonary secretions and may predispose to postoperative pneumonia. In this study, we tested the ability of local anesthetic continuous wound infusion to prevent pneumonia after cardiac surgery with sternotomy and cardiopulmonary bypass (CPB) owing to better analgesia and bronchopulmonary drainage.

METHODS

In this randomized, double-blind, placebo-controlled trial conducted in five academic centers, patients undergoing cardiac surgery with sternotomy and CPB were enrolled from February 2012 until November 2014, and were followed over 30 days. Patients were assigned to a 48-h infusion (10 ml h^-1) of L-bupivacaine (12.5 mg h^-1) or placebo (saline) via a pre-sternal multiperforated catheter. Anesthesia and analgesia protocols were standardized. The primary end point was the incidence of pneumonia during the study period, i.e., until hospital discharge or 30 days. We hypothesized a 30% reduction in the incidence of pneumonia.

RESULTS

Among 1493 randomized patients, 1439 completed the trial. Pneumonia occurred in 36/746 patients (4.9%) in the L-bupivacaine group and in 42/739 patients (5.7%) in the placebo group (absolute risk difference taking into account center and baseline risk of postoperative pneumonia, - 1.3% [95% CI - 3.4; 0.8] P = 0.22). In the predefined subgroup of patients at high risk, L-bupivacaine decreased the incidence of pneumonia (absolute risk difference, - 5.6% [95% CI - 10.0; - 1.1], P = 0.01).

CONCLUSIONS

After cardiac surgery with sternotomy, continuous wound infusion of L-bupivacaine failed to decrease the incidence of pneumonia. These findings do not support the use of local anesthetic continuous wound infusion in this indication. Further study should investigate its effect in high-risk patients.

TRIAL REGISTRATION

EudraCT Number: 2011-003292-10; Clinicaltrials.gov Identifier: NCT01648777.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 39 studies, enrolling a total of 3027 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Persistent postoperative pain after cardiac surgery: a systematic review with meta-analysis regarding incidence and pain intensity

Persistent postoperative pain (PPP) has been described as a complication of cardiac surgery (CS). We aimed to study PPP after CS (PPPCS) by conducting a systematic review of the literature regarding its incidence, intensity, location, and the presence of neuropathic pain, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The review comprised 3 phases: a methodological assessment of 6 different databases identifying potential articles and screening for inclusion criteria by 2 independent reviewers; data extraction; and study quality assessment. Meta-analysis was used to estimate the pooled incidence rates using a random effects model. We have identified 442 potentially relevant studies through database searching. A total of 23 studies (involving 11,057 patients) met our inclusion criteria. Persistent postoperative pain affects 37% patients in the first 6 months after CS, and it remains present more than 2 years after CS in 17%. The reported incidence of PPP during the first 6 months after CS increased in recent years. Globally, approximately half of the patients with PPPCS reported moderate to severe pain. Chest is the main location of PPPCS followed by the leg; neuropathic pain is present in the majority of the patients. This is the first systematic review and meta-analysis to provide estimates regarding incidence and intensity of PPPCS, which elucidates its relevance. There is an urgent need for adequate treatment and follow-up in patients with PPPCS.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 41 studies, enrolling a total of 3143 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Pain alleviation in patients undergoing cardiac surgery; presternal local anesthetic and magnesium infiltration versus conventional intravenous analgesia: a randomized double-blind study

Background

Magnesium is one of the effective, safe local anesthetic adjuvants that can exert an analgesic effect in conditions presenting acute and chronic post-sternotomy pain. We studied the efficacy of continuous infusion of presternal magnesium sulfate with bupivacaine for pain relief following cardiac surgery.

Methods

Ninety adult patients undergoing valve replacement cardiac surgery randomly allocated into three groups. In all patients; a presternal catheter was placed for continuous infusion of either 0.125% bupivacaine and 5% magnesium sulfate (3 ml/h for 48 hours) in group 1, or 0.125% bupivacaine only in the same rate in group 2, versus conventional intravenous paracetamol and ketorolac in group 3. Rescue analgesia was iv 25 µg fentanyl. Postoperative Visual Analog Scale (VAS) and fentanyl consumption during the early two postoperative days were assessed. All patients were followed up over two months for occurrence of chronic post-sternotomy pain.

Results

VAS values showed high significant differences during the first 48 hours with the least pain scale in group 1 and significantly least fentanyl consumption (30.8 ± 7 µg in group 1 vs. 69 ± 18 µg in group 2, and 162 ± 3 in group 3 respectively). The incidence of chronic pain has not differed between the three groups although it was more pronounced in group 3.

Conclusions

Continuous presternal bupivacaine and magnesium infusion resulted in better postoperative analgesia than both presternal bupivacaine alone or conventional analgesic groups.

Pathophysiology, assessment, and management of pain in critically ill adults

PURPOSE

The pathophysiology of pain in critically ill patients, the role of pain assessment in optimal pain management, and pharmacologic and nonpharmacologic strategies for pain prevention and treatment are reviewed.

SUMMARY

There are many short- and long-term consequences of inadequately treated pain, including hyperglycemia, insulin resistance, an increased risk of infection, decreased patient comfort and satisfaction, and the development of chronic pain. Clinicians should have an understanding of the basic physiology of pain and the patient populations that are affected. Pain should be assessed using validated pain scales that are appropriate for the patient's communication status. Opioids are the cornerstone of pain treatment. The use of opioids, administered via bolus dosing or continuous infusion, should be guided by patient-specific goals of care in order to avoid adverse events. A multimodal approach to pain management, including the use of regional analgesia, may improve patient outcomes and decrease opioid-related adverse events, though there are limited relevant data in adult critically ill patient populations. Nonpharmacologic strategies have been shown to be effective adjuncts to pharmacologic regimens that can improve patient-reported pain intensity and reduce analgesic requirements. Analgesic regimens need to take into account patient-specific factors and be closely monitored for safety and efficacy.

CONCLUSION

Acute pain management in the critically ill is a largely underassessed and undertreated area of critical care. Opioids are the cornerstone of treatment, though a multimodal approach may improve patient outcomes and decrease opioid-related adverse events.

The analgesic efficacy of continuous presternal bupivacaine infusion through a single catheter after cardiac surgery

Background:

Median sternotomy, sternal spreading, and sternal wiring are the main causes of pain during the early recovery phase following cardiac surgery.

Aim:

This study was designed to evaluate the analgesic efficacy of continuous presternal bupivacaine infusion through a single catheter after parasternal block following cardiac surgery.

Materials and Methods:

The total of 40 patients (American Society of Anesthesiologist status II, III), 45–60 years old, undergoing coronary – artery bypass grafting were enrolled in this prospective, randomized, double-blind study. A presternal catheter was inserted with continuous infusion of 5 mL/h bupivacaine 0.25% (Group B) or normal saline (Group C) during the first 48 postoperative hrs. Primary outcomes were postoperative morphine requirements and pain scores, secondary outcomes were extubation time, postoperative respiratory parameters, incidence of wound infection, Intensive Care Unit (ICU) and hospital stay duration, and bupivacaine level in blood.

Statistical Methods:

Student's t-test was used to analyze the parametric data and Chi-square test for categorical variables.

Results:

During the postoperative 48 h, there was marked reduction in morphine requirements in Group B compared to Group C, (8.6 ± 0.94 mg vs. 18.83 ± 3.4 mg respectively, P = 0.2), lower postoperative pain scores, shorter extubation time (117 ± 10 min vs. 195 ± 19 min, respectively, P = 0.03), better respiratory parameters (PaO₂/FiO_2, PaCO₂ and pH), with no incidence of wound infection, no differences in ICU or hospital stay duration. The plasma concentration of bupivacaine remained below the toxic threshold (at T24, 1.2 ug/ml ± 0.3 and T48 h 1.7 ± 0.3 ug/ml).

Conclusion:

Continuous presternal bupivacaine infusion has resulted in better postoperative analgesia, reduction in morphine requirements, shorter time to extubation, and better postoperative respiratory parameters than the control group.

Antimicrobial effect of continuous lidocaine infusion in a Staphylococcus aureus-induced wound infection in a mouse model

Continuous infusion of local anesthetics in surgical wounds has been shown to be an effective technique for postoperative analgesia. To investigate the potential antimicrobial effect of continuous local anesthetic infusion, we adapted a mouse model of surgical wound infection to examine effects on antibacterial response. Forty male BALB/c mice were randomized into 2 groups. An incision wound was made over the dorsal flank and instilled with Staphylococcus aureus. An osmotic pump was then implanted to deliver either 0.9% NaCl or 2% lidocaine continuously. Each wound was cultured postoperatively at 2 days, and the colony count of S. aureus was determined. Results showed that the number of colony-forming units of S. aureus measured in wounds treated with lidocaine displayed a nearly 10-fold reduction compared to the wounds in the saline group (P=0.009). The demonstrated antibacterial activity indicates that local anesthetic infusion may play a role in prophylaxis for surgical wound infections.

Does Paravertebral Blockade Facilitate Immediate Extubation after Totally Endoscopic Robotic Mitral Valve Repair Surgery?

Objective

Immediate extubation of select patients in the operating room after cardiac surgery has been shown to be safe and may result in improved hemodynamics and decreased cost perioperatively. The aim of this study was to evaluate whether the addition of paravertebral blockade (PVB) to general anesthesia facilitates extubation in the operating room in patients undergoing totally endoscopic robotic mitral valve repair (TERMR).

Methods

A review of 65 consecutive patients who underwent TERMR between January 2012 and June 2013 at a single institution was conducted. Patients were divided into two groups, one group that received PVB and general anesthesia and a second group that received general anesthesia alone. The data analyzed included quantities of anesthetic administered during surgery and the location of extubation after surgery.

Results

A total of 34 patients received PVB and general anesthesia, whereas 31 received general anesthesia alone. The two groups had similar demographic and surgical data. Patients in the PVB and general anesthesia group were more likely to be extubated in the operating room (67.6%, n = 23 vs 41.9%, n = 13, P = 0.048) and required less intraoperative fentanyl (3.41 μg/kg vs 4.90 μg/kg, P = 0.006). There were no adverse perioperative events in either group related to PVB or extubation.

Conclusions

The addition of PVB to general anesthesia for perioperative pain control facilitated extubation in the operating room in patients undergoing TERMR. Paravertebral blockade allowed for lower intraoperative fentanyl dosing, which may account for the increased incidence of immediate extubation. A detailed prospective study is warranted.

Pharmacotherapy for the prevention of chronic pain after surgery in adults

BACKGROUND

Chronic pain can often occur after surgery, substantially impairing patients' health and quality of life. It is caused by complex mechanisms that are not yet well understood. The predictable nature of most surgical procedures has allowed for the conduct of randomized controlled trials of pharmacological interventions aimed at preventing chronic postsurgical pain.

OBJECTIVES

The primary objective was to evaluate the efficacy of systemic drugs for the prevention of chronic pain after surgery by examining the proportion of patients reporting pain three months or more after surgery. The secondary objective was to evaluate the safety of drugs administered for the prevention of chronic pain after surgery.

SEARCH METHODS

We identified randomized controlled trials (RCTs) of various systemically administered drugs for the prevention of chronic pain after surgery from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 17 July 2013.  

SELECTION CRITERIA

Included studies were double-blind, placebo-controlled, randomized trials involving adults and evaluating one or more drugs administered systemically before, during or after surgery, or both, which measured pain three months or more after surgery.

DATA COLLECTION AND ANALYSIS

Data collected from each study included the study drug name, dose, route, timing and duration of dosing; surgical procedure; proportion of patients reporting any pain three months or more after surgery, reporting at least 4/10 or moderate to severe pain three months or more after surgery; and proportion of participants dropping out of the study due to treatment-emergent adverse effects.

MAIN RESULTS

We identified 40 RCTs of various pharmacological interventions including intravenous ketamine (14 RCTs), oral gabapentin (10 RCTs), oral pregabalin (5 RCTs), non-steroidal anti-inflammatories (3 RCTs), intravenous steroids (3 RCTs), oral N-methyl-D-aspartate (NMDA) blockers (3 RCTs), oral mexiletine (2 RCTs), intravenous fentanyl (1 RCT), intravenous lidocaine (1 RCT), oral venlafaxine (1 RCT) and inhaled nitrous oxide (1 RCT). Meta-analysis suggested a modest but statistically significant reduction in the incidence of chronic pain after surgery following treatment with ketamine but not gabapentin or pregabalin. Results with ketamine should be viewed with caution since most of the included trials were small (that is < 100 participants per treatment arm), which could lead to the overestimation of treatment effect.

AUTHORS' CONCLUSIONS

Additional evidence from better, well designed, large-scale trials is needed in order to more rigorously evaluate pharmacological interventions for the prevention of chronic pain after surgery. Furthermore, available evidence does not support the efficacy of gabapentin, pregabalin, non-steroidal anti-inflammatories, intravenous steroids, oral NMDA blockers, oral mexiletine, intravenous fentanyl, intravenous lidocaine, oral venlafaxine or inhaled nitrous oxide for the prevention of chronic postoperative pain.

Local anaesthetics and regional anaesthesia for preventing chronic pain after surgery

BACKGROUND

Regional anaesthesia may reduce the rate of persistent (chronic) pain after surgery, a frequent and debilitating condition.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of persistent pain six or 12 months after surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 4), PubMed (1966 to April 2012), EMBASE (1966 to May 2012) and CINAHL (1966 to May 2012) without any language restriction. We used a combination of free text search and controlled vocabulary search. The results were limited to randomized controlled clinical trials (RCTs). We conducted a handsearch in reference lists of included trials, review articles and conference abstracts.

SELECTION CRITERIA

We included RCTs comparing local anaesthetics or regional anaesthesia versus conventional analgesia with a pain outcome at six or 12 months after surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data, including information on adverse events. We contacted study authors for additional information. Results are presented as pooled odds ratios (OR) with 95% confidence intervals (CI), based on random-effects models (inverse variance method). We grouped studies according to surgical interventions. We employed the Chi(2) test and calculated the I(2) statistic to investigate study heterogeneity.

MAIN RESULTS

We identified 23 RCTs studying local anaesthetics or regional anaesthesia for the prevention of persistent (chronic) pain after surgery. Data from a total of 1090 patients with outcomes at six months and of 441 patients with outcomes at 12 months were presented. No study included children. We pooled data from 250 participants after thoracotomy, with outcomes at six months. Data favoured regional anaesthesia for the prevention of chronic pain at six months after thoracotomy with an OR of 0.33 (95% CI 0.20 to 0.56). We pooled two studies on paravertebral block for breast cancer surgery; the pooled data of 89 participants with outcomes at five to six months favoured paravertebral block with an OR of 0.37 (95% CI 0.14 to 0.94).The methodological quality of the included studies was intermediate. Adverse effects were not studied systematically and were reported sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered the assessment of effects, especially at 12 months.

AUTHORS' CONCLUSIONS

Epidural anaesthesia may reduce the risk of developing chronic pain after thoracotomy in about one patient out of every four patients treated. Paravertebral block may reduce the risk of chronic pain after breast cancer surgery in about one out of every five women treated. Our conclusions are significantly weakened by performance bias, shortcomings in allocation concealment, considerable attrition and incomplete outcome data. We caution that our evidence synthesis is based on only a few, small studies. More studies with high methodological quality, addressing various types of surgery and different age groups, including children, are needed.

[Postoperative analgesia: comparing continuous epidural catheter infusion of local anesthetic and opioid and continuous wound catheter infusion of local anesthetic]

BACKGROUND AND OBJECTIVES

Continuous wound infusion has been investigated as a method of postoperative pain control and its efficacy has been demonstrated when compared to saline infusion. The objective of this study was to compare the quality of postoperative analgesia, the use of opioids as rescue analgesia, patient satisfaction, and the incidence of complications between epidural catheter infusion of local anesthetic and opioids and continuous wound infusion of local anesthetic.

METHODS

Thirty-eight patients undergoing elective laparotomy under general anesthesia, randomly divided into two groups, participated in this study. Group I (GI) received postoperative patient-controlled epidural analgesia (PCEA) with continuous infusion of ropivacaine and fentanyl, while Group II (GII) receive postoperative patient-controlled continuous wound catheter infusion of ropivacaine. In the postoperative period, the following parameters were assessed: quality of analgesia through the Visual Analogue Scale; use of rescue opioids; and adverse effects driving patient satisfaction.

RESULTS

Decreased pain at rest and with movements (p < 0.05) and lower consumption of rescue opioids (p < 0.05) were observed in GI in all intervals evaluated, as well as greater patient satisfaction in the post anesthesia care unit (PACU). The incidence of complications was similar in both groups except for pruritus which prevailed in GI between 6 (p < 0.05) and 24 (p < 0.001) postoperative hours.

CONCLUSIONS

Postoperative analgesia with opioids and local anesthetics via PCEA was superior to the patient-controlled local anesthetic infusion into surgical wound. The incidence of side effects was similar in both groups.

A meta-analysis of the efficacy of wound catheters for post-operative pain management

Local anesthetics (LA) are injected via catheters placed in surgical wounds for post-operative analgesia. The primary aim of this systematic review was to assess whether LA reduce pain intensity when injected via wound catheters. A literature search was performed from Medline via PubMed, EMBASE and the Cochrane database from 1966 until November 2009. The search strategy included the following key words: pain, postoperative, catheters and local anesthetics. Two co-authors independently read every article that was initially included and extracted data into a pre-defined study record form. A total of 753 studies primarily fit the search criteria and 163 were initially extracted. Of these, 32 studies were included in the meta-analysis. Wound catheters provided no significant analgesia at rest or on activity, except in patients undergoing gynecological and obstetric surgery at 48 h (P=0.03). The overall morphine consumption was lower (≈13 mg) during 0-24 h (P<0.001) in these patients. No significant differences in side effects were found, except for a lower risk of wound breakdown (P=0.048) and a shorter length of hospital stay (P=0.04) in patients receiving LA. A statistically significant heterogeneity was seen between the studies in most end-points. LA injected via wound catheters did not reduce pain intensity, except at 48 h in a subgroup of patients undergoing obstetric and gynecological surgery. Rescue analgesic consumption was also lower in this group at 0-24 h. The magnitude of these effects was small and compounded by pronounced heterogeneity.