Balanced analgesia: what is it and what are its advantages in postoperative pain?

Opioid-Based vs Opioid-Free Anesthesia in Breast Cancer Surgery

Introduction

Breast cancer is the most widely recognized malignant growth in ladies in India and accounts for 14% of all tumors in women. Modified radical mastectomy (MRM) is a surgery done for breast cancer. It leads to about 30% chances of postoperative nausea and vomiting (PONV) and 40% pain in the immediate postoperative period.

Objectives

Changes in blood pressure after intubation, waiting time for postoperative pain medication, and possibility of adverse effects.

Methodology

After the approval of ethical committee, the study was conducted in the procedure and possible complications associated with the procedure were explained to patients. Written informed consent was obtained from each patient.

Result and Conclusion

We conclude that opioid-free anesthesia is "more effective in reducing the incidence of postoperative nausea and vomiting, produces stable hemodynamics, and reduces incidence of side effects when compared with opioid-based general anesthesia in patients undergoing breast cancer surgeries."

Enhanced Recovery Components for Posterior Lumbar Spine Fusion: Harnessing National Data to Compare Protocols

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The aim of this study was to assess the most commonly used components of enhanced recovery after surgery (ERAS) combinations and their relative effectiveness.

SUMMARY OF BACKGROUND DATA

Data is lacking on use and effectiveness of various ERAS combinations which are increasingly used in spine surgery.

MATERIALS AND METHODS

Posterior lumbar fusion cases were extracted from the Premier Healthcare claims database (2006-2016). Seven commonly included components in spine ERAS protocols were identified: (1) multimodal analgesia, (2) tranexamic acid, (3) antiemetics on the day of surgery, (4) early physical therapy, (5) no urinary catheter, (6) no patient-controlled analgesia, and (7) no wound drains. Outcomes were: length of stay, "any complication," blood transfusion, and hospitalization cost. Mixed-effects models measured associations between the most common ERAS combinations and outcomes, separately for 2006-2012 and 2013-2016. Odds ratios (ORs) and 95% confidence intervals (CIs) are reported.

RESULTS

Among 97,419 (74%; 2006-2012) and 34,932 (26%; 2013-2016) cases ERAS component variations decreased over time. The most commonly used combinations included multimodal analgesia, antiemetics, early physical therapy, avoidance of a urinary catheter, patient-controlled analgesia and drains (10% n=9401 and 19% n=6635 in 2006-2012 and 2013-2016, respectively), and did not include tranexamic acid. Multivariable models revealed minor differences between ERAS combinations in terms of length of stay and costs. The most pronounced beneficial effects in 2006-2012 were seen for the second most commonly (compared with less often) used ERAS combination(s) in terms of blood transfusion (OR: 0.65; CI: 0.59-0.71) and "any complication" (OR: 0.73; CI: 0.66-0.80), both P<0.05. In 2013-2016 the third most commonly used ERAS combination showed the strongest effect: blood transfusion OR: 0.63; CI: 0.50-0.78, P<0.05.

CONCLUSIONS

ERAS component variations decreased over time; maximum benefits were particularly seen in terms of transfusion and complication risk reduction. These findings may inform future ERAS utilization and clinical trials comparing various ERAS protocols.

An Update on Multimodal Pain Management After Total Joint Arthroplasty

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Multimodal analgesia has become the standard of care for total joint arthroplasty as it provides superior analgesia with fewer side effects than opioid-only protocols.

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Systemic medications, including nonsteroidal anti-inflammatory drugs, acetaminophen, corticosteroids, and gabapentinoids, and local anesthetics via local infiltration analgesia and peripheral nerve blocks, are the foundation of multimodal analgesia in total joint arthroplasty.

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Ideally, multimodal analgesia should begin preoperatively and continue throughout the perioperative period and beyond discharge.

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There is insufficient evidence to support the routine use of intravenous acetaminophen or liposomal bupivacaine as part of multimodal analgesia protocols.

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.

Optimal Pain Control in Abdominal Wall Reconstruction

Lack of physician familiarity with alternative pain control strategies is a major reason why opioids remain the most commonly used first-line treatment for pain after surgery. This is perhaps most problematic in abdominal wall reconstruction, where opioids may delay ambulation and return of bowel function, while negatively affecting mental status. In this article, we discuss multimodal strategies for optimal pain control in abdominal wall reconstruction. These strategies are straightforward and are proven to improve pain control while minimizing opioid-associated side effects.

Description of a new approach for great auricular and auriculotemporal nerve blocks: A cadaveric study in foxes and dogs

Otitis externa is a painful condition that may require surgical intervention in dogs. A balanced analgesia protocol should combine systemic analgesic agents and local anaesthesia techniques. The aim of the study was to find anatomical landmarks for the great auricular and the auriculotemporal nerves that transmit nociceptive information from the ear pinna and to develop the optimal technique for a nerve block. The study consisted of two phases. In phase I, one fox cadaver was used for dissection and anatomical localization of the auricular nerves to derive landmarks for needle insertion. Eight fox cadavers were subsequently used to evaluate the accuracy of the technique by injecting methylene blue bilaterally. In phase II findings from phase I were applied in four Beagle canine cadavers. A block was deemed successful if more than 0.6 cm of the nerve's length was stained. Successful great auricular nerve block was achieved by inserting the needle superficially along the wing of the atlas with the needle pointing towards the jugular groove. For the auriculotemporal nerve block the needle was inserted perpendicular to the skin at the caudal lateral border of the zygomatic arch, close to the temporal process. The overall success rate was 24 out of 24 (100%) and 22 out of 24 (91%) for the great auricular and the auriculotemporal nerves, respectively, while the facial nerve was stained on three occasions. Our results suggest that it is feasible to achieve a block of the auricular nerves, based on anatomical landmarks, without concurrently affecting the facial nerve.

The evaluation of implementing smart patient controlled analgesic pump with a different infusion rate for different time duration on postoperative pain management

Background

Control of postoperative pain is an important aspect of postoperative patient management. Among the methods of postoperative pain control, patient-controlled analgesia (PCA) has been the most commonly used. This study tested the convenience and safety of a PCA method in which the dose adjusted according to time.

Methods

This study included 100 patients who had previously undergone orthognathic surgery, discectomy, or total hip arthroplasty, and wished to control their postoperative pain through PCA. In the test group (n = 50), the rate of infusion was changed over time, while in the control group (n = 50), drugs were administered at a fixed rate. Patients' pain scores on the visual analogue scale, number of rescue analgesic infusions, side effects, and patients' satisfaction with analgesia were compared between the two groups.

Results

The patients and controls were matched for age, gender, height, weight, and body mass index. No significant difference in the mount of drug administered was found between the test and control groups at 0-24 h after the operation; however, a significant difference was observed at 24-48 h after the operation between the two groups. No difference was found in the postoperative pain score, number of side effects, and patient satisfaction between the two groups.

Conclusions

Patient-controlled anesthesia administered at changing rates of infusion has similar numbers of side effects as infusion performed at a fixed rate; however, the former allows for efficient and safe management of postoperative pain even in small doses.

Perioperative local infiltration anesthesia with ropivacaine has no effect on postoperative pain after total hip arthroplasty

BACKGROUND AND PURPOSE

The local infiltration analgesia (LIA) technique has been widely used to reduce opioid requirements and to improve postoperative mobilization following total hip arthroplasty (THA). However, the evidence for the efficacy of LIA in THA is not yet clear. We determined whether single-shot LIA in addition to a multimodal analgesic regimen would reduce acute postoperative pain and opioid requirements after THA.

PATIENTS AND METHODS

116 patients undergoing primary THA under spinal anesthesia were included in this randomized, double-blind, placebo-controlled trial. All patients received oral opioid-sparing multimodal analgesia: etoricoxib, acetaminophen, and glucocorticoid. The patients were randomized to receive either 150 mL ropivacaine (2 mg/mL) and 0.5 mL epinephrine (1 mg/mL) or 150 mL 0.9% saline. Rescue analgesic consisted of morphine and oxycodone as needed. The primary endpoint was pain during mobilization in the recovery unit. Secondary endpoints were pain during mobilization on the day after surgery and total postoperative opioid requirements on the first postoperative day.

RESULTS

The levels of pain during mobilization-both in the recovery unit and on the day after surgery-and consumption of opioids on the first postoperative day were similar in the 2 groups.

INTERPRETATION

LIA did not provide any extra analgesic effect after THA over and above that from the multimodal analgesic regimen used in this study.

Pain relief management following proximal femoral fractures: Options, issues and controversies

The majority of proximal femoral fractures occur in the elderly population. Safe and adequate pain relief is an integral part of the overall management of hip fractures. Inherent difficulties in the assessment of pain in elderly need to be taken into account and unique considerations should be made regarding the effective analgesia due to different elderly physiology, and their response to trauma and subsequent surgery. The pain management should start as soon as possible and special emphasis should be paid to contemporary methods of regional anaesthesia whilst a multimodal approach should be adopted in the perioperative period. The present review summarises the contemporary treatment options and controversies pertaining to the management of pain in elderly patients with proximal femoral fractures.

Acute pain management in the older person

The proportion of older people in society is growing steadily. This particular group is more likely to be admitted to hospital and a number of papers have highlighted the inadequate or inappropriate assessment and management of their pain, particularly in the perioperative period. Pain relief is possible for the majority of people. This paper aims to give an overview of the assessment and management of pain in older people.

Comparison of pain management after laparoscopic distal gastrectomy with and without epidural analgesia

PURPOSE

The optimal analgesia following laparoscopic distal gastrectomy (LDG) has not been determined; moreover, it has been unclear whether epidural anesthesia has benefits for laparoscopic surgery. In this study, we evaluated the effectiveness of epidural analgesia after LDG.

METHODS

This retrospective study included 84 patients who underwent LDG for gastric cancer. Patients received either combined thoracic epidural and general anesthesia (Epidural group, n = 34) or general anesthesia alone (No epidural group, n = 50). We recorded data on the patients, surgery, postoperative outcomes and anesthesia-related complications.

RESULTS

In the Epidural group, the first day of flatus was significantly earlier (2.21 vs. 2.44 days, p = 0.045) and the number of additional doses of analgesics was significantly lower (2.85 vs. 4.86 doses, p = 0.007) than in the No epidural group. Postoperative urinary retention occurred at a significantly higher rate in the Epidural group (n = 7; 20.6 %) than in the No epidural group (p < 0.001).

CONCLUSION

Epidural anesthesia may reduce the need for additional analgesics after LDG, but increases the risk of urinary retention.

New medications and techniques in ambulatory anesthesia

Novel anesthetic and analgesic agents are currently under development or investigation to improve anesthetic delivery and patient care. The pharmacokinetic and analgesic profiles of these agents are especially tailored to meet the challenges of rapid recovery and opioid minimization associated with ambulatory anesthesia practice.

Finding the 'ideal' regimen for fentanyl-based intravenous patient-controlled analgesia: how to give and what to mix?

PURPOSE

This analysis was done to investigate the optimal regimen for fentanyl-based intravenous patient-controlled analgesia (IV-PCA) by finding a safe and effective background infusion rate and assessing the effect of adding adjuvant drugs to the PCA regimen.

MATERIALS AND METHODS

Background infusion rate of fentanyl, type of adjuvant analgesic and/or antiemetic that was added to the IV-PCA, and patients that required rescue analgesics and/or antiemetics were retrospectively reviewed in 1827 patients who underwent laparoscopic abdominal surgery at a single tertiary hospital.

RESULTS

Upon multivariate analysis, lower background infusion rates, younger age, and IV-PCA without adjuvant analgesics were identified as independent risk factors of rescue analgesic administration. Higher background infusion rates, female gender, and IV-PCA without additional 5HT₃ receptor blockers were identified as risk factors of rescue antiemetics administration. A background infusion rate of 0.38 μg/kg/hr [area under the curve (AUC) 0.638] or lower required rescue analgesics in general, whereas, addition of adjuvant analgesics decreased the rate to 0.37 μg/kg/hr (AUC 0.712) or lower. A background infusion rate of 0.36 μg/kg/hr (AUC 0.638) or higher was found to require rescue antiemetics in general, whereas, mixing antiemetics with IV-PCA increased the rate to 0.37 μg/kg/hr (AUC 0.651) or higher.

CONCLUSION

Background infusion rates of fentanyl between 0.12 and 0.67 μg/kg/hr may safely be used without any serious side effects for IV-PCA. In order to approach the most reasonable background infusion rate for effective analgesia without increasing postoperative nausea and vomiting, adding an adjuvant analgesic and an antiemetic should always be considered.

Effect of perioperative electroacupuncture as an adjunctive therapy on postoperative analgesia with tramadol and ketamine in prostatectomy: a randomised sham-controlled single-blind trial

OBJECTIVES

To study the analgesic effect of electroacupuncture (EA) as perioperative adjunctive therapy added to a systemic analgesic strategy (including tramadol and ketamine) for postoperative pain, opioid-related side effects and patient satisfaction.

METHODS

In a sham-controlled participant- and observer-blinded trial, 75 patients undergoing radical prostatectomy were randomly assigned to two groups: (1) EA (n=37; tramadol+ketamine+EA) and (2) control (n=38; tramadol+ketamine). EA (100 Hz frequency) was applied at LI4 bilaterally during the closure of the abdominal walls and EA (4 Hz) was applied at ST36 and LI4 bilaterally immediately after extubation. The control group had sham acupuncture without penetration or stimulation. The following outcomes were evaluated: postoperative pain using the Numerical Rating Scale (NRS) and McGill Scale (SF_MPQ), mechanical pain thresholds using algometer application close to the wound, cortisol measurements, rescue analgesia, Spielberger State Trait Anxiety Inventory (STAI Y-6 item), patient satisfaction and opioid side effects.

RESULTS

Pain scores on the NRS and SF_MPQ were significantly lower and electronic pressure algometer measurements were significantly higher in the EA group than in the control group (p<0.001) at all assessments. In the EA group a significant decrease in rescue analgesia was observed at 45 min (p<0.001) and a significant decrease in cortisol levels was also observed (p<0.05). Patients expressed satisfaction with the analgesia, especially in the EA group (p<0.01). Significant delays in the start of bowel movements were observed in the control group at 45 min (p<0.001) and 2 h (p<0.05).

CONCLUSIONS

Adding EA perioperatively should be considered an option as part of a multimodal analgesic strategy.

Ilioinguinal-iliohypogastric nerve block with intravenous dexketoprofen improves postoperative analgesia in abdominal hysterectomies

BACKGROUND AND OBJECTIVE

In this study, our aim was to evaluate the effects of intravenous dexketoprofen trometamol with ilioinguinal and iliohypogastric nerve block on analgesic quality and morphine consumption after total abdominal hysterectomy operations.

METHODS

We conducted this randomized controlled clinical study on 61 patients. The study was conducted in the operation room, post-anesthesia care unit, and inpatient clinic. We randomly grouped the 61 patients into control group (group C), block group (group B) and dexketoprofen-block group (group DB). Before the skin incision performed after anesthesia induction, we performed ilioinguinal iliohypogastric block (group C given saline and group P and DB given levobupivacaine). In contrast to group C and B, group DB was given dexketoprofen. We administered morphine analgesia to all patients by patient-controlled analgesia (PCA) during the postoperative 24 hours. We recorded Visual Analogue Scale (VAS), satisfaction scores, morphine consumption and side effects during postoperative 24 hours.

RESULTS

We found the DB group's VAS scores to be lower than the control group and block group's (p < 0.05) values at postoperative 1(st), 2(nd), 6(th) and 12(th) hours. VAS scores of group C were higher than of group B at postoperative first 2 hours. Time to first PCA demand was longer, morphine consumption values were lower and satisfaction scores were higher in group DB than in the other two groups (p < 0.05).

CONCLUSIONS

Ilioinguinal-iliohypogastric nerve block with IV dexketoprofen increases patient satisfaction by decreasing opioid consumption, increasing patient satisfaction, which suggests that dexketoprofen trometamol is an effective non-steroidal anti-inflammatory analgesic in postoperative analgesia.

A prospective study of early removal of the urethral catheter after colorectal surgery in patients having epidural analgesia as part of the Enhanced Recovery After Surgery programme

AIM

Early removal of the urethral catheters is part of the enhanced postoperative recovery programme (ERAS). The effect of epidural anaesthesia on urinary retention was investigated in patients after colorectal resection.

METHOD

A prospective cohort study of all patients having colorectal surgery within an ERAS programme that included insertion of an epidural catheter over the last 5 years.

RESULTS

Two-hundred and ten patients had an epidural and a urethral catheter postoperatively. The duration of catheterization was not recorded in one patient who was therefore excluded from the study. One-hundred and eighteen patients had a trial without catheter (TWOC) prior to stopping the epidural (early TWOC). Ninety-one patients had TWOC after the epidural was stopped (late TWOC). Sixteen (7.6%) patients went into urinary retention (14 early TWOC and two late TWOC). The rate of urinary retention in the early TWOC group was significantly higher than that in the late TWOC group (11.9% vs 2.2%; χ(2), P = 0.009). Those who underwent a laparoscopic resection were significantly more likely to have undergone an early TWOC (χ(2), P = 0.001); however, there was no difference in retention rates between open and laparoscopic surgery (χ(2), P = 0.402). Pelvic surgery was not significantly associated with an increased risk of postoperative urinary retention (χ(2), P = 0.627). Male sex was not significantly associated with urinary retention (χ(2), P = 0.087). In the early TWOC group 86% had the catheter removed within 24 hours of surgery.

CONCLUSION

Early TWOC with epidural analgesia running significantly increases the risk of urinary retention; however, it was still successful in 88% of patients.

Safety and efficacy of fast-track surgery in laparoscopic distal gastrectomy for gastric cancer: a randomized clinical trial

BACKGROUND

Fast-track surgery has been shown to enhance postoperative recovery in several surgical fields. This study aimed to evaluate the safety and efficacy of fast-track surgery in laparoscopic distal gastrectomy.

METHODS

The present study was designed as a single-center, randomized, unblinded, parallel-group trial. Patients were eligible if they had gastric cancer for which laparoscopic distal gastrectomy was indicated. The fast-track surgery protocol included intensive preoperative education, a short duration of fasting, a preoperative carbohydrate load, early postoperative ambulation, early feeding, and sufficient pain control using local anesthetics perfused via a local anesthesia pump device, with limited use of opioids. The primary endpoint was the duration of possible and actual postoperative hospital stay.

RESULTS

We randomized 47 patients into a fast-track group (n=22) and a conventional pathway group (n=22), with three patients withdrawn. The possible and actual postoperative hospital stays were shorter in the fast-track group than in the conventional group (4.68±0.65 vs. 7.05±0.65; P<0.001 and 5.36±1.46 vs. 7.95±1.98; P<0.001). The time to first flatus and pain intensity were not different between groups; however, a greater frequency of additional pain control was needed in the conventional group (3.64±3.66 vs. 1.64±1.33; P=0.023). The fast-track group was superior to the conventional group in several factors of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, including: fatigue, appetite loss, financial problems, and anxiety. The complication and readmission rates were similar between groups.

CONCLUSIONS

Fast-track surgery could enhance postoperative recovery, improve immediate postoperative quality of life, and be safely applied in laparoscopic distal gastrectomy.

Peri-operative ketamine with the ambulatory elastometric infusion pump as an adjuvant to manage acute postoperative pain after spinal fusion in adults: a prospective randomized trial

Background

In this study, we assessed the effectiveness of ketamine as an alternative to non-steroidal anti-inflammatory drugs (NSAID), to manage acute postoperative pain after spinal fusion when given intravenously via a patient-controlled analgesia (PCA) pump in which the dose was proportional to that of fentanyl.

Methods

Forty patients undergoing 1-2 level spinal fusion were enrolled in this study. Patients were intraoperatively randomized into two groups to receive intravenous PCA consisting either of fentanyl 0.4 µg/ml/kg (control group) or fentanyl 0.4 µg/ml/kg with ketamine 30 µg/ml/kg (ketamine group) after intravenous injection of a loading dose. The loading dose in the control group was fentanyl 1 µg/kg with normal saline equal to ketamine volume and in the ketamine group it was fentanyl 1 µg/kg with ketamine 0.2 mg/kg. The verbal numerical rating scale (NRS), fentanyl and ketamine infusion rate, and side effects were evaluated at 1, 24, and 48 hours after surgery.

Results

There were no significant differences in patient demographics, duration of surgery and anesthesia or intra-operative opioids administration. We did not find any significant differences in the mean infusion rate of intraoperative remifentanil or postoperative fentanyl or in the side effects between the groups, but we did find a significant difference in the NRS between the groups.

Conclusions

Based on our results, we conclude that a small dose of ketamine (0.5-2.5 µg/kg/min) proportional to fentanyl is not only safe, but also lowers postoperative pain intensity in patients undergoing spinal fusion, although the opioid-sparing effects of ketamine were not demonstrated.

A randomized, controlled trial validates a peripheral supra-additive antihyperalgesic effect of a paracetamol-ketorolac combination

The combination of paracetamol with non-steroidal anti-inflammatory drugs (NSAIDs) is widely used; however, the nature and mechanism of their interaction are still debated. A double-blind, pharmacokinetic/pharmacodynamic, randomized, cross-over, placebo-controlled study was carried out in human healthy volunteers. The aim was to explore the existence of a positive interaction between paracetamol 1 g and ketorolac 20 mg administered intravenously on experimental pain models in human beings. The effects of the paracetamol-ketotolac combination were compared with similar doses of respective single analgesic and to placebo on the sunburn model (UVB-induced inflammation), cold pain tolerance and the nociceptive flexion reflex. The kinetics of the plasma concentrations of paracetamol and ketorolac were measured using 2D-liquid chromatography-mass spectrometry. Thirteen volunteers were screened, and 11 completed the study. Ketorolac significantly decreased primary hyperalgesia to heat stimuli compared with paracetamol (p < 0.014). The combination performed better than paracetamol (p < 0.001) and placebo (p < 0.042), increasing heat pain threshold by 1.5°C. The combination radically reduced primary hyperalgesia to mechanical stimulation (39%) compared with placebo (p < 0.002) and single agents (paracetamol p < 0.024 and ketorolac p < 0.032). The combination also reduced, slightly although significantly, the intensity of pain (10%) for the cold pressor test (versus placebo: p < 0.012, paracetamol: p < 0.019 and ketorolac p < 0.004). None of the treatments significantly affected the central models of pain at this dosage level. No pharmacokinetic interactions were observed. These results suggest a supra-additive pharmacodynamic interaction between paracetamol and ketorolac in an inflammatory pain model. The mechanism of this interaction could mainly rely on a peripheral contribution of paracetamol to the effect of NSAIDs.

Effect of rectal diclofenac in reducing postoperative pain and rescue analgesia requirement after cardiac surgery

BACKGROUND

Adequate analgesic medication is mandatory after coronary artery bypass grafting (CABG) surgery. The aim of this study was to assess the analgesic efficacy, side effects, and need for rescue analgesia after CABG surgery comparing diclofenac and placebo rectal suppository.

METHODS

Thirty-seven consenting adults undergoing elective CABG surgery were randomly assigned in a double-blind fashion to receive either rectal diclofenac 100 mg (Group 1, n = 19) or placebo suppository (Group 2, n = 18) postoperatively, just after extubation. Both groups were given intravenous tramadol as a rescue analgesic. Pain scores in the two groups were assessed on a 10-cm visual analog scale at 0, 0.5, 1, 1.5, 2, 6, 12, 18, and 24 hours after suppository administration. Rescue analgesic consumption, sedation, nausea, and vomiting in both the groups were also recorded.

RESULTS

Twenty-four-hour tramadol consumption in Group 1 was 92.5 +/- 33.5 mg compared to 157.5 +/- 63.4 mg in Group 2 (P = 0.002). Patients in the placebo group had significantly greater pain scores 1.5 to 12 hours after extubation. Group 1 patients were significantly more awake compared to Group 2 (P < 0.05). The incidence of postoperative nausea was less in Group 1 than in Group 2 (P = 0.001). Though not statistically significant, three patients in Group 2 each had a single episode of vomiting, whereas no patient had vomiting in Group 1.

CONCLUSION

Rectal diclofenac suppository with tramadol provides adequate pain relief after cardiac surgery, and also reduces tramadol consumption and side effects commonly associated with tramadol.

[Effect of sublingual oxybutynin in postoperative pain after radical retropubic prostatectomy]

INTRODUCTION

Total prostatectomy (TP) is one of the referential treatments of localized cancer of the prostate gland. Urethrovesical anastomosis and urinary catheterization may be sources of strong contractions of the detrusor muscle responsible for intense pain which is added to parietal pain. This study evaluates the efficiency of oxybutynin in the treatment of this postoperative pain (POP).

MATERIAL AND METHOD

Forty-five patients due to benefit from a TP by laparotomy were included in this prospective study. A urinary catheter was put in place during the operation. Patients were randomly split into two groups in the postoperative care room. Group P (n = 23) received a placebo in tablet form and group O (n = 22) received 5mg of oxybutynin in sublingual form. The POP was evaluated every 2 hours using the Visual Analogue pain Scale (VAS 0:10).

RESULTS

The accumulated dose of tramadol after 8 hours was 110.8 mg in group P and 39.7 mg in group O (p < 0.05). For group P, 15/23 of the patients (65%) were in pain versus 4/22 (18%) in group O. The VAS scores of group P were higher (4.1 +/- 1) than those of group O (1.2 +/- 0.9). For group P, when the PCA dose of tramadol was inefficient, a tablet of oxybutynin 5 mg brought the VAS scores down to the same level of those of group O within 2 hours. No side effects linked to the antimuscarinic action were observed.

CONCLUSION

Oxybutynin given in sublingual form reduced, at postoperative stage, the frequency and intensity of pain linked to the bladder wound and to the catheter after TP. Its use for the POP of the bladder section reduced the consumption of postoperative analgesia.

Wound infiltration with magnesium sulphate and ropivacaine mixture reduces postoperative tramadol requirements after radical prostatectomy

PURPOSE

This prospective, randomized, double-dummy study was undertaken to compare the effects of magnesium sulphate (MgSO(4)) administered by the intravenous vs. the infiltration route on postoperative pain and analgesic requirements.

METHODS

Forty ASA I or II men scheduled for radical retropubic prostatectomy under general anaesthesia were randomized into two groups (n=20 each). Two medication sets A and B were prepared at the pharmacy. Each set contained a minibag of 50 ml solution for IV infusion and a syringe of 45 ml for wound infiltration. Group MgSO(4).IV patients received set A with 50 mg/kg MgSO(4) in the minibag and 190 mg of ropivacaine in the syringe. Group MgSO(4)/L received set B with isotonic saline in the minibag and 190 mg of ropivacaine +750 mg of MgSO(4) in the syringe. The IV infusion was performed over 30 min at induction of anaesthesia and the surgical wound infiltration was performed during closure. Pain was assessed every 4 h, using a 100-point visual analogue scale (VAS). Postoperative analgesia was standardized using IV paracetamol (1 g/6 h) and tramadol was administered via a patient-controlled analgesia system. The follow-up period was 24 h.

RESULTS

The total cumulative tramadol consumption was 221 +/- 64.1 mg in group MgSO4.IV and 134 +/- 74.9 mg in group MgSO(4).L (P<0.01). VAS pain scores were equivalent in the two groups throughout the study. No side-effects, due to systemic or local MgSO(4) administration, were observed.

CONCLUSION

Co-administration of MgSO(4) with ropivacaine for postoperative infiltration analgesia after radical retropubic prostatectomy produces a significant reduction in tramadol requirements.

Intra-articular depot formulation principles: role in the management of postoperative pain and arthritic disorders

The joint cavity constitutes a discrete anatomical compartment that allows for local drug action after intra-articular injection. Drug delivery systems providing local prolonged drug action are warranted in the management of postoperative pain and not least arthritic disorders such as osteoarthritis. The present review surveys various themes related to the accomplishment of the correct timing of the events leading to optimal drug action in the joint space over a desired time period. This includes a brief account on (patho)physiological conditions and novel potential drug targets (and their location within the synovial space). Particular emphasis is paid to (i) the potential feasibility of various depot formulation principles for the intra-articular route of administration including their manufacture, drug release characteristics and in vivo fate, and (ii) how release, mass transfer and equilibrium processes may affect the intra-articular residence time and concentration of the active species at the ultimate receptor site.

[Physico-chemical stability and sterility of non-opioid analgesics in solution]

OBJECTIVES

The combination of non-opioid analgesic drugs (P: paracetamol, K: ketoprofen and N: nefopam) is currently recommended for postoperative pain control. In practice, these analgesics are often administered in the same solution. We investigated the chemical stability and sterility of three mixtures of analgesics (P+K, P+N and K+N).

METHODS

For each mixture, concentrations of active principles were measured using high-performance liquid chromatography over 24 hours. These mixtures were cultured for microbiological colonization.

RESULTS

Our study demonstrated chemical and bacteriologic stability of these three mixtures over a 24-hour period. The results allow the use of P+K, P+N and K+N in the same ready to use solution.

[New substances and applications for postoperative pain therapy]

The onset of postoperative pain is the result of various pathophysiological mechanisms and depends on the type of surgery performed. Therefore, any adequate postoperative pain treatment requires multimodal and procedure-specific analgesia. In addition to reducing perioperative complications and improving patient comfort, optimal postoperative pain management also represents an important quality characteristic which can influence the patient in their choice of hospital. In the past 1-2 years, known groups of substances have been rediscovered for postoperative pain therapy (e.g., Gabapentin and Pregabalin, i.v. Lidocaine, Ketamine or glucocorticoids), while new substances (coxibe, oral oxycodone+naloxone) and applications have been developed. The present overview article discusses the advantages and disadvantages of these substances and analgesic methods, as well as their specific areas of application.

Lack of impact of intravenous lidocaine on analgesia, functional recovery, and nociceptive pain threshold after total hip arthroplasty

BACKGROUND

The analgesic effect of perioperative low doses of intravenous lidocaine has been demonstrated after abdominal surgery. This study aimed to evaluate whether a continuous intravenous low-dose lidocaine infusion reduced postoperative pain and modified nociceptive pain threshold after total hip arthroplasty.

METHODS

Sixty patients participated in this randomized double-blinded study. Patients received lidocaine 1% (lidocaine group) with a 1.5 mg/kg intravenous bolus in 10 min followed by a 1.5 mg . kg . h intravenous infusion or saline (control group). These regimens were started 30 min before surgical incision and stopped 1h after skin closure. Lidocaine blood concentrations were measured at the end of administration. In both groups, postoperative analgesia was provided exclusively by patient-controlled intravenous morphine. Pain scores, morphine consumption, and operative hip flexion were recorded over 48 h. In addition, pressure pain thresholds and the extent of hyperalgesia around surgical incision were systematically measured at 24 and 48 h.

RESULTS

In comparison with the placebo, lidocaine did not induce any opioid-sparing effect during the first 24 h (median [25-75% interquartile range]; 17 mg [9-28] vs. 15 mg [8-23]; P = 0.54). There was no significant difference regarding the effects of lidocaine and placebo on pain score, pressure pain thresholds, extent in the area of hyperalgesia, and maximal degree of active hip flexion tolerated. Mean plasma lidocaine concentration was 2.1 +/- 0.4 mug/ml.

CONCLUSION

Low dose perioperative intravenous lidocaine after total hip arthroplasty offers no beneficial effect on postoperative analgesia and does not modify pressure and tactile pain thresholds.

Ketamine as an adjunct to postoperative pain management in opioid tolerant patients after spinal fusions: a prospective randomized trial

Management of acute postoperative pain is challenging, particularly in patients with preexisting narcotic dependency. Ketamine has been used at subanesthetic doses as a N-methyl D-aspartate (NMDA) receptor antagonist to block the processing of nociceptive input in chronic pain syndromes. This prospective randomized study was designed to assess the use of ketamine as an adjunct to acute pain management in narcotic tolerant patients after spinal fusions. Twenty-six patients for 1-2 level posterior lumbar fusions with segmental instrumentation were randomly assigned to receive ketamine or act as a control. Patients in the ketamine group received 0.2 mg/kg on induction of general anesthesia and then 2 mcg kg(-1) hour(-1) for the next 24 hours. Patients were extubated in the operating room and within 15 minutes of arriving in the Post Anesthesia Care Unit (PACU) were started on intravenous patient-controlled analgesia (PCA) hydromorphone without a basal infusion. Patients were assessed for pain (numerical rating scale [NRS]), narcotic use, level of sedation, delirium, and physical therapy milestones until discharge. The ketamine group had significantly less pain during their first postoperative hour in the PACU (NRS 4.8 vs 8.7) and continued to have less pain during the first postoperative day at rest (3.6 vs 5.5) and with physical therapy (5.6 vs 8.0). Three patients in the control group failed PCA pain management and were converted to intravenous ketamine infusions when their pain scores improved. Patients in the ketamine group required less hydromorphone than the control group, but the differences were not significant. Subanesthetic doses of ketamine reduced postoperative pain in narcotic tolerant patients undergoing posterior spine fusions.

Sublingual oxybutynin reduces postoperative pain related to indwelling bladder catheter after radical retropubic prostatectomy †

BACKGROUND

Bladder discomfort related to an indwelling catheter can exacerbate postoperative pain. It mimics overactive bladder syndrome that is resistant to conventional opioid therapy. Muscarinic receptor antagonists are effective for treatment of the overactive bladder. The aim of this study was to assess the efficacy of oxybutynin in the management of postoperative pain after radical prostatectomy.

METHOD

Forty-six ASA I or II men undergoing radical retropubic prostatectomy under general anaesthesia were randomly assigned to two groups, in a double-blind fashion: Group O and Group P (n = 23 each). Group O and Group P received, respectively, sublingual oxybutynin 5 mg or placebo every 8 h during the 24 h after surgery. A 16F Foley catheter was placed during the vesico-urethral anastomosis and the balloon inflated with 10 ml of saline. Pain was assessed in the recovery room starting 10 min after extubation using a 100-point visual analogue scale (VAS). The patients were asked to specify whether pain was related to the surgical incision or bladder pain. Standardized postoperative analgesia included acetaminophen and tramadol administered via a patient-controlled analgesia system.

RESULTS

The incidence of bladder catheter pain was 65% (15 of 23 patients) in Group P compared with 17% (4 of 23 patients) in Group O (P < 0.01). Overall VAS scores at rest were significantly lower in Group O. Cumulative tramadol consumption was 322.9(124.3) mg [mean(sd)] in Group P and 146(48) mg in Group O (P < 0.01). No oxybutynin-related side-effects were reported.

CONCLUSIONS

Sublingual oxybutynin is an effective treatment for postoperative pain after radical retropubic prostatectomy and produces a significant reduction in tramadol requirements.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Diflunisal salts of bupivacaine, lidocaine and morphine

The present work describes the characterization of diflunisal salts of the analgesic agents bupivacaine, lidocaine, and morphine including their solubility behaviour and release characteristics from solutions and selected salt suspensions in vitro using the rotating dialysis cell model. The solubility of the 1:1 salts at pH 7.4 differed by a factor of 9 with the bupivacaine and lidocaine salts representing the poorest and most soluble salt (0.73 and 6.6mM, respectively). Common ion effects were observed for the diflunisal salts of bupivacaine and morphine when various concentrations of the lidocaine-diflunisal salt were present in aqueous buffer (pH 7.4). The most pronounced salting-out effect was observed for the poorest soluble salt. From Setschenow type plots apparent salting-out constants of 265 M(-1) (bupivacaine) and 54.7 M(-1) (morphine) were calculated. After instillation of mixed salt suspensions comprising the diflunisal salts of bupivacaine and lidocaine into the donor cell of the release model, lidocaine appeared rapidly in the acceptor phase. After clearance of lidocaine from the donor cell, equal and constant fluxes of bupivacaine and diflunisal were observed. The residence times of bupivacaine within the donor compartment was prolonged with increasing lidocaine-diflunisal salt load in the mixed suspensions whereas the slopes of the linear part of the bupivacaine release profiles were affected to a minor extent only. The obtained data indicate that local multimodal analgesia, characterized by rapid onset and extended duration of action, can be achieved upon injection of mixed suspensions of salts differing with respect to aqueous solubility comprising a common ion into a small body compartment (such as the joint cavity).

Perioperative pain management

The under-treatment of postoperative pain has been recognised to delay patient recovery and discharge from hospital. Despite recognition of the importance of effective pain control, up to 70% of patients still complain of moderate to severe pain postoperatively. The mechanistic approach to pain management, based on current understanding of the peripheral and central mechanisms involved in nociceptive transmission, provides newer options for clinicians to manage pain effectively. In this article we review the rationale for a multimodal approach with combinations of analgesics from different classes and different sites of analgesic administration. The pharmacological options of commonly used analgesics, such as opioids, NSAIDs, paracetamol, tramadol and other non-opioid analgesics, and their combinations is discussed. These analgesics have been shown to provide effective pain relief and their combinations demonstrate a reduction in opioid consumption. The basis for using non-opioid analgesic adjuvants is to reduce opioid consumption and consequently alleviate opioid-related adverse effects. We review the evidence on the opioid-sparing effect of ketamine, clonidine, gabapentin and other novel analgesics in perioperative pain management. Most available data support the addition of these adjuvants to routine analgesic techniques to reduce the need for opioids and improve quality of analgesia by their synergistic effect. Local anaesthetic infiltration, epidural and other regional techniques are also used successfully to enhance perioperative analgesia after a variety of surgical procedures. The use of continuous perineural techniques that offer prolonged analgesia with local anaesthetic infusion has been extended to the care of patients beyond hospital discharge. The use of nonpharmacological options such as acupuncture, relaxation, music therapy, hypnosis and transcutaneous nerve stimulation as adjuvants to conventional analgesia should be considered and incorporated to achieve an effective and successful perioperative pain management regimen.

Intravenous magnesium sulphate decreases postoperative tramadol requirement after radical prostatectomy*

BACKGROUND

The purpose of this study was to assess whether the addition of intravenous magnesium sulphate (Mg) at the induction of anaesthesia to a balanced anaesthetic protocol including wound infiltration, paracetamol and tramadol resulted in improved analgesic efficiency after radical prostatectomy.

METHODS

We conducted a randomized, double-blind, controlled study. Thirty ASA I or II males scheduled to undergo radical retropubic prostatectomy with general anaesthesia were prospectively assigned to one of the two groups (n = 15 each). The Mg group (Gr Mg) received 50 mg kg-1 of MgSO4 in 100 mL of isotonic saline over 20 min immediately after induction of anaesthesia and before skin incision. The patients in the control group (Gr C) received the same volume of saline over the same period. At the time of abdominal closure, wound infiltration with 190 mg (40 mL) of ropivacaine was performed in both groups. Pain was assessed by a 10-point visual analogue scale in the recovery room starting from the time of tracheal extubation. Standardized postoperative analgesia included paracetamol and tramadol administered via a patient-controlled analgesia device.

RESULTS

In the postoperative period, both groups experienced an identical pain course evolution. Cumulative mean tramadol dose after 24 h was 226 mg in the magnesium group and 446 mg in the control group (P < 0.001). Postoperative nausea occurred in two patients in each group. Two vs. eight patients required analgesic rescue in magnesium and control groups, respectively (P = 0.053).

CONCLUSIONS

This study shows that intravenous magnesium sulphate reduces tramadol consumption when used as a postoperative analgesic protocol in radical prostatectomy.

Isobolographic analysis of the dual-site synergism in the antinociceptive response of tramadol in the formalin test in rats

Tramadol is an atypical opioid with a complex mechanism of action including a synergistic interaction between the parent drug and an active metabolite. The local action of the parent drug is poorly documented. This study was designed to evaluate the site-site interaction of the antinociception produced by tramadol given by two different routes. The effects of individual and fixed-ratio combinations of intraplantar (i.pl.) and intraperitoneal (i.p.) tramadol were evaluated using the formalin test in rats. Isobolographic analysis was employed to identify the synergy produced by combinations. In both first and second phases of the formalin test, tramadol was active not only by the systemic (ED50 10.2+/-2.1 and 7.1+/-0.5 mg/kg i.p.) but also by the local route (ED50 171.0+/-44.8 and 134.6 microg/paw i.pl.). The isobolographic analysis revealed a "self-synergism" in the antinociceptive effect between the two routes of administration, as the experimental ED50 (211.1+/-13.6 and 45.9+/-3.9 "dose units" phase 1 and 2, respectively) of the combination was significantly lower than the theoretical ED50 (422.2+/-50.5 and 138.5+/-9.2 "dose units"). The mechanism underlying this self-synergism appears to be partially opioid since systemic but not local naloxone reversed the potentiation. The observed dual-site interaction in the antinociceptive action of tramadol provides insights for alternatives in the management of pain.