Epidural Clonidine for Postoperative Pain After Total Knee Arthroplasty: A Dose–Response Study

Adding Ketamine to Epidural Morphine Does Not Prolong Postoperative Analgesia After Lumbar Laminectomy or Discectomy

BACKGROUND

Epidural opioids provide effective postoperative analgesia after lumbar spine surgery. Ketamine has been shown to reduce opioid-induced central sensitization and hyperalgesia. We hypothesized that adding ketamine to epidural opioids would prolong the duration of analgesia and enhance analgesic efficacy after lumbar spine surgery.

METHODS

American Society of Anesthesiologists physical status class I to II patients aged between 18 and 70 years with normal renal function undergoing lumbar laminectomy were recruited into this single-center randomized trial. Patients were randomized to receive either single-dose epidural morphine (group A) or epidural morphine and ketamine (group B) for postoperative analgesia. The primary objective was to compare the duration of analgesia as measured by time to the first postoperative analgesic request. Secondary objectives were the comparison of pain scores at rest and movement, systemic hemodynamics, and the incidence of side effects during the first 24 hours after surgery.

RESULTS

Fifty patients were recruited (25 in each group), of which data from 48 were available for analysis. The mean±SD duration of analgesia was 20±6 and 23±3 hours in group A and group B, respectively ( P =0.07). There were 12/24 (50%) patients in group A and 17/24 (71%) patients in group B who did not receive rescue analgesia during the first 24-hour postoperative period ( P =0.07). Pain scores at rest and movement, systemic hemodynamics, and postoperative complications were comparable between the groups.

CONCLUSIONS

The addition of ketamine to epidural morphine did not prolong the duration of analgesia after lumbar laminectomy.

A Comparative Study of Morphine and Clonidine as an Adjunct to Ropivacaine in Paravertebral Block for Modified Radical Mastectomy

Background General anesthesia (GA) is a standard for breast malignant surgery. The issue of postoperative pain as well as the high occurrence of nausea and vomiting have prompted the quest for a superior methodology for tormenting the executives with fewer complications. Over the most recent couple of years, paravertebral block (PVB) has acquired huge fame either in combination with GA or alone for anesthetic management. In this study, we aim to evaluate the efficacy of morphine and clonidine as an adjunct to ropivacaine in PVB in breast cancer patients undergoing modified radical mastectomy. Methods In this study, a total of 90 patients were divided into the following three groups (30 each) based on a computer-generated random table. Group C (control): PVB with 0.25% ropivacaine (19 ml) 1 ml saline; Group M: PVB with 0.25% ropivacaine (19 ml) + 20 microgram/kg body weight morphine; Group N: PVB with 0.25% ropivacaine (19 ml) + 1.0 microgram/kg body weight clonidine. The postoperative pain intensity was recorded using the visual analog scale (VAS), and sedation was observed by the Ramsay Sedation Scale (RSS) score. Results The VAS was similar at zero hours, two hours, and four hours in the postoperative period among all the groups. There was a significant (p = 0.003) difference in VAS from six hours to 20 hours in the postoperative period among the groups. A significant (p < 0.05) difference was observed among the groups at eight hours to 20 hours. The first requirement of analgesia was significantly (p = 0.001) higher in Group N (7.70 ± 1.74) than in Group C (4.43 ± 1.43) and Group M (7.33 ± 2.21). Conclusion Morphine in the PVB provides better postoperative analgesia. The consumption of rescue analgesia was significantly reduced in the morphine group as compared to the clonidine group. The procedure also proved to be safe as no complication was encountered in the PVB in our study.

Effects of magnesium sulfate on periarticular infiltration analgesia in total knee arthroplasty: a prospective, double-blind, randomized controlled trial

BACKGROUND

To investigate whether adding magnesium sulfate to a periarticular infiltration analgesia (PIA) cocktail could improve pain control and functional outcomes in patients undergoing total knee arthroplasty (TKA).

METHODS

Ninety patients were randomly assigned to the magnesium sulfate and control groups, with 45 patients in each group. In the magnesium sulfate group, patients were given a periarticular infusion of a cocktail of analgesics consisting of epinephrine, ropivacaine, magnesium sulfate, and dexamethasone. The control group received no magnesium sulfate. The primary outcomes consisted of visual analogue scale (VAS) pain scores, postoperative morphine hydrochloride consumption for rescue analgesia, and time to first rescue analgesia. Secondary outcomes were postoperative inflammatory biomarkers (IL-6 and CRP), postoperative length of stay, and knee functional recovery (assessed by knee range of motion, quadriceps strength, daily mobilization distance, and time to first straight-leg raising). Tertiary outcomes included the postoperative swelling ratio and complication rates.

RESULTS

Within 24 h of surgery, patients in the magnesium sulfate group had markedly lower VAS pain scores during motion and at rest. After the addition of magnesium sulfate, the analgesic effect was dramatically prolonged, leading to a reduction in morphine dosage within 24 h and the total morphine dosage postoperatively. Postoperative inflammatory biomarker levels were significantly reduced in the magnesium sulfate group compared with the control. There were no considerable differences between the groups in terms of the postoperative length of stay and knee functional recovery. Both groups had similar postoperative swelling ratios and incidences of complications.

CONCLUSIONS

The addition of magnesium sulfate to the analgesic cocktail for PIA can prolong postoperative analgesia, decrease the consumption of opioids, and effectively alleviate early postoperative pain after TKA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR2200056549. Registered on 7 February 2022, https://www.chictr.org.cn/showproj.aspx?proj=151489 .

Effects of adding oral clonidine to standard treatments on pain intensity of patients with acute renal colic: A randomized clinical trial

Background:

The aim of this study was to compare the effect of adding oral clonidine to standard treatments on pain intensity in patients with acute renal colic.

Materials and Methods:

This is a randomized clinical trial that was performed in 2020 in Isfahan. The study population consisted of 200 patients with renal colic. Pain of the patients was assessed using Visual Analog Scale. Patients were then randomized into 4 groups of 50 patients. Group A received 0.1 mg/kg morphine and clonidine tablets (0.2 mg). Group B received morphine and placebo. Group C received 30 mg ketorolac and clonidine tablets. Group D received 30 mg ketorolac and placebo tablets. Pain of patients was assessed. 0.05 mg/kg morphine was administered and repeated every 40 min if the pain was not reduced.

Results:

Our data showed that there was a significant difference between pains of patient by the time of admission in groups (P = 0.04). However, no significant differences were observed between pains of patients in different measuring times (P > 0.05). Using general linear model, we showed that the decreases in pain scores of each group were significant (P < 0.05) but there were no significant differences in pains of patients in different measuring times (P > 0.05). Our data showed that Group A and Group C had lowest frequencies of morphine administrations while Groups B and D had the highest frequencies (P < 0.001).

Conclusion:

We showed that administration of clonidine in patients with renal colic resulted in better pain control and lower morphine injections.

Assessing outcome in postoperative pain trials: are we missing the point? A systematic review of pain-related outcome domains reported in studies early after total knee arthroplasty

ABSTRACT

The management of acute postoperative pain remains suboptimal. Systematic reviews and Cochrane analysis can assist with collating evidence about treatment efficacy, but the results are limited in part by heterogeneity of endpoints in clinical trials. In addition, the chosen endpoints may not be entirely clinically relevant. To investigate the endpoints assessed in perioperative pain trials, we performed a systematic literature review on outcome domains assessing effectiveness of acute pain interventions in trials after total knee arthroplasty. We followed the Cochrane recommendations for systematic reviews, searching PubMed, Cochrane, and Embase, resulting in the screening of 1590 potentially eligible studies. After final inclusion of 295 studies, we identified 11 outcome domains and 45 subdomains/descriptors with the domain "pain"/"pain intensity" most commonly assessed (98.3%), followed by "analgesic consumption" (88.8%) and "side effects" (75.3%). By contrast, "physical function" (53.5%), "satisfaction" (28.8%), and "psychological function" (11.9%) were given much less consideration. The combinations of outcome domains were inhomogeneous throughout the studies, regardless of the type of pain management investigated. In conclusion, we found that there was high variability in outcome domains and inhomogeneous combinations, as well as inconsistent subdomain descriptions and utilization in trials comparing for effectiveness of pain interventions after total knee arthroplasty. This points towards the need for harmonizing outcome domains, eg, by consenting on a core outcome set of domains which are relevant for both stakeholders and patients. Such a core outcome set should include at least 3 domains from 3 different health core areas such as pain intensity, physical function, and one psychological domain.

The effect of morphine added to periarticular multimodal drug injection or spinal anesthesia on pain management and functional recovery after total knee arthroplasty

BACKGROUND

The efficacy of morphine added to periarticular multimodal drug injection (PMDI) for pain management after total knee arthroplasty (TKA) is controversial. Adding morphine to spinal anesthesia has reportedly improved pain relief for the first 24 h. We examined the effect of morphine added to PMDI or spinal anesthesia on pain management and functional recovery after TKA.

METHODS

A total of 97 patients were randomized into three groups: in Group A (34 patients), 10 mg morphine was added to PMDI; Group B (31 patients), 0.1 mg morphine was added to spinal anesthesia; and Group C (32 patients), morphine was added to neither the PMDI nor spinal anesthetic. To evaluate the efficacy of added morphine for pain management, we assessed rest pain, the number of times analgesics were used, and the time period until the first analgesic use. The adverse effects of morphine were assessed by counting the numbers of times vomiting occurred and antiemetics were used. Functional recovery was evaluated by recording the range of motion of the knee and the date of ability to walk.

RESULTS

Rest pain was the least in Group B at 6 and 12 h after operation. The number of times analgesics were used was the least in Group B. The time period until the first analgesic use was the longest in Group B. The number of vomiting episodes was the least in Group C. The number of times antiemetics were used was higher in Group A than in Group C. There were no significant differences in the range of motion and date of ability to walk among the three groups.

CONCLUSIONS

The efficacy of morphine added to PMDI was limited, and that of morphine added to spinal anesthesia disappeared within 20 h postoperatively. Adding morphine to PMDI or spinal anesthesia did not improve functional recovery and caused some adverse effects.

Comparative Evaluation of Ropivacaine and Fentanyl Versus Ropivacaine and Fentanyl with Clonidine for Postoperative Epidural Analgesia in Total Knee Replacement Surgery

Introduction

Clonidine an alpha 2 adrenoceptor agonist possesses analgesic properties and has been used as an adjuvant in epidural analgesia. The addition of clonidine to other analgesics may result in enhanced analgesia through additive mechanisms or synergistic mechanisms. The enhanced analgesia may lead to a decrease in the dosage of analgesic drugs along with reduction of side effects.

Aim

The purpose of this study was to evaluate the effect of adding clonidine to epidural ropivacaine and fentanyl mixture in terms of quality of analgesia and side effects in patients of total knee replacement surgery.

Materials and Methods

A prospective randomised double blind study was conducted on 60 patients of ASA physical status I, II and III who underwent unilateral total knee replacement surgery under combined spinal epidural anaesthesia. Patients were divided into two Groups A and B randomly. Postoperatively Group A received continuous epidural infusion of ropivacaine 2 mg.ml ^-1 and fentanyl 2 μg.ml ^-1 along with clonidine 2 μg.ml^-1 in the range of 3-7 ml.hr^-1 while Group B received the ropivacaine and fentanyl epidural solution. The postoperative VAS scores, haemodynamic parameters, motor block, sedation, nausea, vomiting and any other significant side effects were noted. The two groups were compared with student's t-test, Pearson's Chi square test and t-test using SPSS statistical software.

Results

Visual analog scale scores were lower in Group A (3.38) than in Group B (3.72). The average infusion rate was lower in Group A (4.7 ± 0.7 ml.hr ^-1) than in Group B (5.5 ± 0.7 ml.hr^-1). Patients in Group A required less dosage of rescue pain medication Paracetamol (1g i.v.), diastolic pressure and heart rate were lower in Group A. The groups were comparable in terms of sedation, motor block and nausea vomiting.

Conclusion

Clonidine added to a ropivacaine and fentanyl mixture augmented the postoperative epidural analgesia without significant side effects.

Evaluation of Efficacy of Epidural Clonidine with 0.5% Bupivacaine for Postoperative Analgesia for Orthopaedic Lower Limb Surgeries

OBJECTIVE

The objective of this study is to evaluate the efficacy of epidural clonidine in intra and postoperative analgesia, the level of sedation caused by clonidine and monitor its side effects.

MATERIALS AND METHODS

Forty patients of ASA1 & ASA2 scheduled for lower limb orthopaediac surgeries were chosen for the study. Study group received 50μg of clonidine diluted to 1ml along with first dose of epidural injection and Control group received 1ml of normal saline along with first dose of epidural. Intra and postoperative vitals, verbal pain rating scale (VRS), sedation score and number of rescue anlgesics required postoperatively were noted. Patients received rescue analgesic when VRS was 1.

RESULTS

Addition of clonidine to bupivacaine definitely improves the quality of analgesia by reducing the overall pain score, prolonging the duration of the time of first rescue analgesia and causing reduction of total analgesic consumption in the postoperative period without any hemodynamic instability. Sedation may be beneficial during the intraoperative period.

CONCLUSION

Epidural clonidine produces long lasting, good quality analgesia with good level of sedation and with minimal side effects.

Addition of epidural Clonidine enhances postoperative analgesia: A double-blind study in total knee- replacement surgeries

Background:

This study was undertaken to evaluate the analgesic effect of the combination of epidural Clonidine with Bupivacaine versus epidural Bupivacaine alone in patients undergone knee replacement surgery.

Materials and Methods:

A randomized double-blind design was used, and 60 adult patients (40-60 years) of ASA grade I and II scheduled for post-operative pain relief in total knee replacement surgeries by epidural Clonidine were studied. Patients received either an epidural Clonidine (1μg/kg) with Bupivacaine (1.5mg/kg) group CL (n=30) or Bupivacaine alone group CT (n=30) for Knee replacement surgeries. The pain score, blood pressure, heart rate, respiratory rate were measured at fixed times during the first 24 h after operation. Onset and duration of sensory and motor blockade, duration of analgesia, and analgesic requirement were compared.

Results:

The onset of sensory anesthesia was faster (493.8±31.66 in sec.) and the duration was significantly longer in Clonidine group (334.2 min). Requirement of supplementary analgesia (Inj. diclofenac) was markedly decreased in Clonidine group as evident from the findings that in control group 18 patients required 3 supplemental analgesic doses in first 24 hours as compared to only 3 patients in Clonidine group. Epidural Clonidine produced a significant decrease (P less than 0.05) in heart rate and blood pressure, whereas the respiratory rate was not affected. We also observed for side effects in both the groups. Incidence of significant hypotension was higher, 8 patients (26%) in Clonidine group compared to 2 patient (6%) in control group. Incidence of dryness of mouth was higher, 12 patients (48%) in Clonidine group compared to 5 (18%) in control group.

Conclusion:

The addition of Clonidine to Bupivacaine epiduraly prolongs motor and sensory block and analgesia, without an increased incidence of side effects.

Dexmedetomidine as an adjunct to epidural analgesia after abdominal surgery in elderly intensive care patients: A prospective, double-blind, clinical trial

BACKGROUND

The ideal postoperative analgesia management of elderly surgical patients in intensive care units (ICUs) is continually being investigated.

OBJECTIVE

The purpose of this study was to assess the effectiveness and tolerability of IV administration of dexmedetomidine as an adjunct to a low-dose epidural bupivacaine infusion for postoperative analgesia after abdominal surgery in elderly patients in the ICU.

METHODS

ICU patients aged >70 years undergoing abdominal surgery were eligible for the study. A lumbar epidural catheter was inserted at the beginning of the surgery with no medication. On arrival at the ICU, the catheter was loaded with 0.25% bupivacaine 25 mg at the T8 to T10 sensory level, and a continuous infusion of 0.125% bupivacaine was started at 4 to 6 mL/h in combination with patient-controlled epidural analgesia (PCEA) of fentanyl (4 μg/bolus) for pain treatment. Patients in the treatment group received dexmedetomidine as an IV loading dose of 0.6 pg/kg for 30 minutes followed by continuous infusion at 0.2 μg/kg · h(-1). Patients in the control group were not administered dexmedetomidine. The effectiveness of the pain relief was determined using a visual analog scale (VAS) (0 = no pain to 10 = worst pain imaginable) at rest. VAS score, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure, and arterial blood gases were monitored periodically for 24 hours after surgery. If required, tenoxicam (20-mg IV bolus) was used to ensure a VAS score of ≤3. The number of times PCEA and tenoxicam were administered and the occurrence of adverse events (AEs) were also recorded.

RESULTS

Sixty patients (34 men, 26 women; mean [SD] age, 75.96 [4.25] years; mean [SD] weight, 74.13 [10.62] kg) were included in the study. VAS scores were significantly lower in the dexmedetomidine group compared with the control group at hours 1, 2, and 12 (VAS [hour 1]: 2.8 [0.4], P < 0.001; VAS [hour 2]: 2.7 [0.5], P < 0.001; and VAS [hour 12]: 0.9 [0.7], P 0.044). The mean number of administrations of fentanyl via PCEA was significantly greater in the control group compared with the dexmedetomidine group (2.20 vs 6.63 times; P < 0.001). The mean number of administrations of tenoxicam was significantly lower in the treatment group than the control group (0.27 vs 1.07 times; P < 0.001). In the control group, the decreases in sedation at 0, 8, 12, 16, and 20 hours were significant compared with baseline (P = 0.024, P = 0.001, P = 0.020, P < 0.001, and P = 0.005, respectively). Mean HR, SBR and AEs (eg, bradycardia [HR <60 beats/min], respiratory depression [respiratory rate <8 breaths/min], hypotension \SBP <90 mm Hg], oversedation, hypoxia, and hypercapnia) decreased significantly in the dexmedetomidine group (all, P < 0.05). Significantly more patients in the dexmedetomidine group rated their satisfaction with postoperative pain control as excellent compared with the control group (12 vs 6 patients; P = 0.014).

CONCLUSION

Intravenous dexmedetomidine was effective and generally well tolerated as an analgesic adjunct to epidural low-dose bupivacaine infusion for pain treatment, with lower need for opioids after abdominal surgery in these elderly intensive care patients than in the control group.

Evaluation of the effect of magnesium sulphate vs. clonidine as adjunct to epidural bupivacaine

For treatment of intra and postoperative pain, no drug has yet been identified that specifically inhibits nociception without associated side effects. Magnesium has antinociceptive effects in animal and human models of pain. The current prospective randomised double-blind study was undertaken to establish the effect of addition of magnesium or clonidine, as adjuvant, to epidural bupivacaine in lower abdominal and lower limb surgeries. A total of 90 American Society of Anesthesiology (ASA) grade I and II patients undergoing lower abdominal and lower limb surgeries were enrolled to receive either magnesium sulphate (Group B) or clonidine (Group C) along with epidural bupivacaine for surgical anaesthesia. All patients received 19 ml of epidural bupivacaine 0.5% along with 50 mg magnesium in group B, 150 mcg clonidine in Group C, whereas in control group (Group A), patients received same volume of normal saline. Onset time, heart rate, blood pressure, duration of analgesia, pain assessment by visual analogue score (VAS) and adverse effects were recorded. Onset of anaesthesia was rapid in magnesium group (Group B). In group C there was prolongation of duration of anaesthesia and sedation with lower VAS score, but the incidence of shivering was higher. The groups were similar with respect to haemodynamic variables, nausea and vomiting. The current study establishes magnesium sulphate as a predictable and safe adjunct to epidural bupivacaine for rapid onset of anaesthesia and clonidine for prolonged duration of anaesthesia with sedation.

Unilateral spinal anaesthesia for outpatient surgery: a comparison between hyperbaric bupivacaine and bupivacaine-clonidine combination

BACKGROUND

Low-dose hyperbaric bupivacaine has been used to produce unilateral spinal anaesthesia for outpatient surgery. Unilateral spinal anaesthesia is associated with reduction of hypotension, faster recovery and increased patient satisfaction. Small doses of clonidine have shown effectiveness in intensifying spinal anaesthesia. We investigated the effect of adding 15 microg of clonidine to 5 mg hyperbaric bupivacaine on unilaterality.

METHODS

Sixty patients undergoing outpatient knee arthroscopy were randomly allocated to receive either 1.2 ml (6 mg) of hyperbaric bupivacaine or a 1.2 ml solution containing 1.0 ml (5 mg) hyperbaric bupivacaine, 0.1 ml (75 microg) clonidine and 0.1 ml sterile water. The motor block was assessed by a modified Bromage scale and the sensory block by a pinprick.

RESULTS

There was a significant difference in the spread of anaesthesia between the operated and contralateral sides in both groups. Seventy-seven per cent of the blocks were unilateral in group B and 73% in group B-C. There was no significant difference between the groups, in unilaterality. The motor block was prolonged in group B-C but it did not affect home-readiness. Patients receiving clonidine needed more vasopressors. There was a significant difference in blood pressures between the groups, being lower in group B-C after 1 h 45 min.

CONCLUSION

Using 5 mg hyperbaric bupivacaine with 15 microg of clonidine, the unilaterality can be achieved and spinal anaesthesia intensified without affecting home-readiness. More vasopressors are needed in the beginning, but after the surgery patients experienced less pain.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.