Is Intraoperative Remifentanil Associated With Acute or Chronic Postoperative Pain After Prolonged Surgery? An Update of the Literature

The Influence of Audiovisual Distraction on Pain Reduction During Transcatheter Aortic Valve Implantation Under Monitored Anesthesia Care: A Prospective Randomized Trial

OBJECTIVES

To investigate the effect of an audiovisual distraction system on the dose of remifentanil for perioperative sedation during transcatheter aortic valve implantation under monitored anesthesia care.

DESIGN

Single-center prospective randomized nonblinded study.

SETTING

Tertiary referral academic hospital.

PARTICIPANTS

Ninety patients who underwent transfemoral transcatheter aortic valve implantation between July 2019 and July 2021.

INTERVENTIONS

Patients were randomized to use either a novel audiovisual distraction system during the intervention (n = 45) or standard care without an audiovisual distraction system (n = 45).

MEASUREMENTS AND MAIN RESULTS

Standardized questionnaires were given to each patient at admission and before and after the intervention to assess their levels of anxiety. Primary endpoints were the average and peak infusion rates of remifentanil. All patients were considered for the final analysis according to an intention-to-treat design. No relevant differences in pre- and postinterventional anxiety status were observed between the groups. Similarly, there were no significant differences in reported pain scores (p = 0.364). The average infusion rate (p = 0.028) and peak infusion rate (p = 0.025) of remifentanil were lower in the group with an audiovisual distraction system.

CONCLUSIONS

Audiovisual distraction is a useful adjunct to reduce the dose of remifentanil under monitored anesthesia care during transcatheter aortic valve implantation. Larger studies are needed to evaluate potential positive effects on patient satisfaction, incidence of delirium, and possible economic benefits.

Erector spinae plane block reduces opioid consumption and improves incentive spirometry volume after cardiac surgery: A retrospective cohort study

BACKGROUND

Effective postoperative pain management is vital in cardiac surgery to prevent opioid dependency and respiratory complications. Previous studies on the erector spinae plane (ESP) block have focused on single-shot applications or immediate postoperative outcomes. This study evaluates the efficacy of continuous ESP block vs conventional care in reducing opioid consumption and enhancing respiratory function recovery postcardiac surgery over 72 hours.

METHODS

A retrospective study at a tertiary hospital (January 2021-July 2022) included 262 elective cardiac surgery patients. Fifty-three received a preoperative ESP block, matched 1:1 with a control group (n = 53). The ESP group received 0.5% ropivacaine intraoperatively and 0.16% ropivacaine every 4 hours postoperatively. Outcomes measured were cumulative oral morphine equivalent (OME) dose within 72 hours postextubation, daily maximum numerical rating scale (NRS) ≥3, incentive spirometry volume, and %baseline performance, stratified by surgery type (sternotomy or thoracotomy).

RESULTS

Significant OME reduction was observed in the ESP group (sternotomy: median decrease of 113 mg, 95% CI: 60-157.5 mg, p < 0.001; thoracotomy: 172.5 mg, 95% CI: 45-285 mg, p = 0.010). The ESP group also had a lower risk of daily maximum NRS ≥3 (adjusted OR sternotomy: 0.22, p < 0.001; thoracotomy: 0.07, p < 0.001), a higher incentive spirometry volumes (sternotomy: mean increase of 149 mL, p = 0.019; thoracotomy: 521 mL, p = 0.017), and enhanced spirometry %baseline (sternotomy: mean increase of 11.5%, p = 0.014; thoracotomy: 26.5%, p < 0.001).

CONCLUSION

Continuous ESP block was associated with a reduction of postoperative opioid requirements, lower instances of pain scores ≥3, and improve incentive spirometry performance following cardiac surgery. These benefits appear particularly prominent in thoracotomy patients. Further prospective studies with larger sample size are required to validate these findings.

Comparing Apotel and Remifentanil for Multimodal Patient-Controlled Analgesia in Postoperative Pain Management Following Total Knee Arthroplasty Surgery: A Randomized Controlled Trial

Background

Total knee arthroplasty (TKA) is a standard surgical procedure for individuals with debilitating knee arthritis. Effective postoperative pain management is essential for successful recovery, although traditional opioid-based methods have limitations.

Objectives

This study aimed to compare the efficacy of Apotel and remifentanil patient-controlled analgesia in managing postoperative pain after TKA.

Methods

This double-blind, randomized, controlled clinical trial took place at Amir-al-Momenin and Qods Hospitals in Arak, Iran, spanning from June 2022 to September 2023. Sixty-two eligible patients scheduled for knee joint replacement were randomly assigned to receive either Apotel (Group A) or remifentanil (Group R) as part of multimodal analgesia administered via a pain pump for postoperative pain relief in TKA. The study assessed hemodynamic parameters, pain levels (measured using the Visual Analog Scale), analgesic duration, and narcotic consumption. Statistical analyses were performed using SPSS v.27 and Plotly.

Results

Subjects exhibited no statistically significant differences in age, gender distribution, duration of surgery, or anesthesia. The hemodynamic status assessment in the recovery room showed no significant differences in SPO2, PR, or MAP between the groups. However, remifentanil demonstrated superior effectiveness in reducing pain over 24 hours post TKA surgery compared to Apotel, as evidenced by lower average Visual Analog Scale (VAS) scores (P < 0.001), longer duration without the need for narcotic painkillers (P < 0.001), and lower cumulative opioid analgesic consumption in Group R (P < 0.001).

Conclusions

Remifentanil demonstrates superior pain control in a multimodal pain management approach compared to Apotel, providing sustained pain reduction over 24 hours post-surgery. Moreover, remifentanil offers longer-lasting pain relief and results in lower cumulative narcotic painkiller consumption compared to Apotel.

Effect of opioid-free anesthesia on post-operative period in cytoreductive surgery with hyperthermic intraperitoneal chemotherapy: a propensity score matched study

BACKGROUND

Postoperative pain after cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is important. It appears essential to reduce postoperative pain and morphine consumption.

METHODS

Retrospective study in a university hospital comparing patient benefiting from CRS-HIPEC under opioid-free anesthesia (OFA; dexmedetomidine) to those anesthetized with opioid anesthesia (OA; remifentanil) using a propensity score matching method. The main objective was the impact of OFA on postoperative morphine consumption in the first 24 h after surgery.

RESULTS

102 patients were included, matching on the propensity score allowed selecting 34 unique pairs analyzed. Morphine consumption was lower in the OFA group than in the OA group (3.0 [0.00-11.0] mg/24 h vs. 13.0 [2.5-25.0] mg/24 h; p = 0.02). In multivariable analysis, OFA was associated with a reduction of 7.2 [0.5-13.9] mg of postoperative morphine (p = 0.04). The rate of renal failure with a KDIGO-score > 1 was lower in the OFA group than in the OA group (12% vs. 38%; p = 0.01). There was no difference between groups concerning length of surgery/anesthesia, norepinephrine infusion, volume of fluid therapy, post-operative complications, rehospitalization or ICU readmission within 90 days, mortality, and postoperative rehabilitation.

CONCLUSION

Our results suggest that OFA for CRS-HIPEC patients appears safe and is associated with less postoperative morphine use and acute kidney injury.

Effect of Remifentanil on Acute and Chronic Postsurgical Pain in Patients Undergoing Cardiac Surgery: A Systematic Review and Meta-analysis

OBJECTIVES

Our purpose was to explore the effect of remifentanil on acute and chronic postsurgical pain after cardiac surgery.

MATERIALS AND METHODS

Randomized controlled trials were retrieved from electronic databases, such as PubMed, Cochrane Library, China National Knowledge Internet databases, Scopus, and Web of Science. A systematic review, meta-analysis, and trial sequential analysis (TSA) were performed. Basic information and outcomes were extracted from the included studies. The primary outcome was chronic postsurgical pain. Secondary outcomes were scores of postsurgical pain and morphine consumption within 24 hours after cardiac surgery. Risk of bias (ROB) assessment was based on the Cochrane ROB tool version 2. The overall quality of the evidence was rated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Seven studies consisting of 658 patients were enrolled in the meta-analysis. A single study had a high ROB and 2 studies had a moderate ROB. The incidence of chronic postsurgical pain (4 studies [415 patients]; risk ratio: 1.02 [95% CI: 0.53 to 1.95]; P = 0.95; I2 = 59%; TSA-adjusted CI: 0.78 to 1.20) and the postsurgical pain score (2 studies [196 patients]; mean difference: 0.09 [95% CI: -0.36 to 0.55]; P = 0.69; I2 = 0%; TSA-adjusted CI: -0.36 to 0.55) were not statistically different between the 2 groups. However, morphine consumption (6 studies [569 patients]; mean difference: 6.94 [95% CI: 3.65 to 10.22]; P < 0.01; I2 = 0%; TSA-adjusted CI: 0.00 to 0.49) was higher in the remifentanil group than in the control group.

CONCLUSION

There was not enough evidence to prove that remifentanil can increase the incidence of chronic postsurgical pain after cardiac surgery, but interestingly, the results tended to support a trend toward increased complications in the intervention group. However, there was moderate certainty evidence that the use of remifentanil increases the consumption of morphine for analgesia, and more direct comparison trials are needed to inform clinical decision-making with greater confidence.

A random forest algorithm-based prediction model for moderate to severe acute postoperative pain after orthopedic surgery under general anesthesia

BACKGROUND

Postoperative pain is one of the most common complications after surgery. In order to detect early and intervene in time for moderate to severe postoperative pain, it is necessary to identify risk factors and construct clinical prediction models. This study aimed to identify significant risk factors and establish a better-performing model to predict moderate to severe acute postoperative pain after orthopedic surgery under general anesthesia.

METHODS

Patients who underwent orthopedic surgery under general anesthesia were divided into patients with moderate to severe pain group (group P) and patients without moderate to severe pain group (group N) based on VAS scores. The features selected by Lasso regression were processed by the random forest and multivariate logistic regression models to predict pain outcomes. The classification performance of the two models was evaluated through the testing set. The area under the curves (AUC), the accuracy of the classifiers, and the classification error rate for both classifiers were calculated, the better-performing model was used to predict moderate to severe acute postoperative pain after orthopedic surgery under general anesthesia.

RESULTS

A total of 327 patients were enrolled in this study (228 in the training set and 99 in the testing set). The incidence of moderate to severe postoperative pain was 41.3%. The random forest model revealed a classification error rate of 25.2% and an AUC of 0.810 in the testing set. The multivariate logistic regression model revealed a classification error rate of 31.3% and an AUC of 0.764 in the testing set. The random forest model was chosen for predicting clinical outcomes in this study. The risk factors with the greatest and second contribution were immobilization and duration of surgery, respectively.

CONCLUSIONS

The random forest model can be used to predict moderate to severe acute postoperative pain after orthopedic surgery under general anesthesia, which is of potential clinical application value.

Intra-articular remifentanil on postoperative pain in knee arthroscopic surgery; a double blind randomized clinical trial

BACKGROUND

We aimed to assess the efficacy of intra-articular remifentanil in relieving postoperative pain after knee arthroscopy.

METHODS

We conducted a double-blind randomized clinical trial study on 60 patients. Patients were divided into two equal groups. The control group received 25 ml of intra-articular normal saline, and the intervention group received 200 μg of remifentanil dissolved in 25 ml of saline. We evaluated at rest postoperative pain at 1, 3, 6, 12, 18, and 24 h after the surgery using the Visual Analog Scale (VAS). Patients with VAS scores of 4 or more received meperidine (pethidine). The first time meperidine was requested and the total amount of meperidine consumed was recorded.

RESULTS

Out of 60 patients, 49 were male (81.6%), and the mean age of participants was 32.71 (7.02) years. An hour after the surgery, the control group showed a mean VAS score of 8.66 (1.26), and decreased to 2.53 (1.67) at the end of 24 h. The intervention group started with a mean VAS score of 2.23 (1.81) and ended at 0.10 (0.305). All patients in the control group and 11 (36.7%) patients in the intervention group asked for analgesics during follow-up. The mean total meperidine dose in the control and intervention groups was 108.33 (23.97) mg and 13.33 (19.40) mg, respectively (P < 0.001; 95% confidence interval of the difference 83.72 to 106.27).

CONCLUSIONS

Intra-articular remifentanil may decrease postoperative pain and analgesic requirements in patients undergoing knee arthroscopy.

The mechanisms and management of persistent postsurgical pain

An estimated 10%-50% of patients undergoing a surgical intervention will develop persistent postsurgical pain (PPP) lasting more than 3 months despite adequate acute pain management and the availability of minimally invasive procedures. The link between early and late pain outcomes for surgical procedures remains unclear-some patients improve while others develop persistent pain. The elective nature of a surgical procedure offers a unique opportunity for prophylactic or early intervention to prevent the development of PPP and improve our understanding of its associated risk factors, such as pre-operative anxiety and the duration of severe acute postoperative pain. Current perioperative pain management strategies often include opioids, but long-term consumption can lead to tolerance, addiction, opioid-induced hyperalgesia, and death. Pre-clinical models provide the opportunity to dissect mechanisms underpinning the transition from acute to chronic, or persistent, postsurgical pain. This review highlights putative mechanisms of PPP, including sensitisation of peripheral sensory neurons, neuroplasticity in the central nervous system and nociceptive signalling along the neuro-immune axis.

Nalmefene vs. dexmedetomidine for prevention of postoperative hyperalgesia in patients undergoing laparoscopic gynecological surgery with remifentanil infusion: A randomized double-blind controlled trial

Intraoperative remifentanil infusion may paradoxically induce post-surgical hyperalgesia. Dexmedetomidine reportedly reduces opioid-induced hyperalgesia. Nalmefene selectively reverses several side-effects of opioids without impairing analgesia. Herein, this randomized, double-blind controlled trial investigated whether nalmefene, dexmedetomidine, and both drugs combined prevent remifentanil-induced hyperalgesia. One hundred and fifty patients undergoing elective laparoscopic gynecological surgery under desflurane anesthesia randomly received either intraoperative sufentanil 0.20 μg kg^-1 (Group S), or remifentanil 0.20 μg kg^-1 min^-1 (Group R), or remifentanil and pre-anesthesia nalmefene 0.20 μg kg^-1 (Group N), or remifentanil and pre-anesthesia dexmedetomidine 0.50 μg kg^-1 (Group D), or remifentanil and the combination of dexmedetomidine 0.25 μg kg^-1 and nalmefene 0.10 μg kg^-1 (Group DN). The threshold of postoperative mechanical hyperalgesia (primary outcome) was measured with von Frey filaments. We also recorded pain intensity, analgesic consumptions, hyperalgesic area, and side-effects for 24 h postoperatively. Compared with Group S, remifentanil reduced hyperalgesic threshold on the forearm [mean 89.4 (SD 13.7) vs. 62.2 (10.7) g, p < 0.001] at postoperative 24 h. Pain threshold on the forearm at postoperative 24 h was significantly lower in Group R than in Groups N, D and DN [62.2 (10.7) vs. 71.1 (12.3), 72.4 (12.9) and 78.0 (13.8) g]. Compared with Group R, Postoperative pain intensity, analgesic consumption and hyperalgesic area were lower likewise in Groups D and DN. However, the incidence of intraoperative bradycardia was lower and post-anesthesia recovery time was shorter in Group DN than Group D. Preoperative therapy of dexmedetomidine and nalmefene combined attenuates postoperative hyperalgesia in patients undergoing laparoscopic gynecological surgery under desflurane-remifentanil anesthesia.

Opioid-Sparing Analgesic Effects from Interscalene Block Impact Anesthetic Management During Shoulder Arthroscopy: A Retrospective Observational Study

Purpose

Ultrasound-guided interscalene nerve block (UISB) is commonly used to alleviate postoperative pain during shoulder arthroscopy. This retrospective observational study aimed to evaluate the intraoperative advantages and analgesic effects of preoperative UISB.

Patients and Methods

In this retrospective observational study, a total of 170 patients underwent shoulder arthroscopy at a tertiary medical center in southern Taiwan throughout 2019. After applying the exclusion criteria, 142 of these cases were included, with 74 and 68 in the UISB group and control groups, respectively. The primary outcome was the evaluation of intraoperative morphine milligram equivalent (MME) consumption. Secondary outcomes were sevoflurane consumption, the use of intraoperative antihypertensive drugs, and postoperative visual analog scale (VAS) scores in the post-anesthesia care unit (PACU) and in the ward at 24 h after surgery.

Results

Preoperative UISB effectively reduced opioids and volatile gases during surgery, supported by a 48.1% and 14.8% reduction in the median intraoperative MME and sevoflurane concentrations, respectively, and showed less need for antihypertensive drugs. The preoperative UISB group also showed significantly better performance on the VAS in both the PACU and ward.

Conclusion

Taken together, the preoperative UISB reduced not only intraoperative MME and sevoflurane consumption but also had satisfactory VAS scores in both the PACU and ward without any symptomatic respiratory complications. In summary, preoperative UISB is a reliable adjuvant analgesic technique and a key factor in achieving opioid-sparing and sevoflurane-sparing anesthesia and multimodal analgesia during shoulder arthroscopy.

Persistent and acute postoperative pain after cardiac surgery with anterolateral thoracotomy or median sternotomy: A prospective observational study

OBJECTIVE

The primary objective of this study was to compare the association between cardiac surgical approach (thoracotomy vs. sternotomy) and incidence of persistent postoperative pain at 3 months. Secondary objectives were the incidence and intensity of persistent pain at 6 and 12 months, acute postoperative pain, analgesic requirement and its side effects.

DESIGN

Single-center, prospective, observational study. Recruitment between December 2017 and August 2018.

SETTING

Perioperative care at university-affiliated tertiary care centre.

PATIENTS

202 adults scheduled for cardiac surgery. Patients with chronic pain or behavioural disorder were excluded.

INTERVENTIONS

Thoracotomy (n = 106) and sternotomy (n = 96).

MEASUREMENTS

Pain scores and pain medication requirements from extubation until hospital discharge. Persistent postoperative pain was assessed using a telephone questionnaire.

MAIN RESULTS

Incidence and intensity of pain was not significantly different between thoracotomy or sternotomy either in the short- or in the long-term follow-up. Incidence of persistent postoperative pain showed no differences between groups (30.2 vs 22.9% at 3 months (p = 0.297), 10.4 vs 7.3% at 6 months (p = 0.364) and 7.5 vs 7.3% at 12 months (p = 0.518) in thoracotomy and sternotomy group). A significant decrease of pain incidence was observed between 3 and 6 months (p < 0.001) but not between 6 and 12 months (p = 0.259) in both groups. ANOVA of repeated measures adjusted for confounding variable showed a decrease of acute pain intensity over time (p = 0.001) with no difference between groups (p = 0.145). Acute pain medication requirements were not different between the groups (p = 0.237 for piritramide and p = 0.743 for oxycodone) with no difference in their side effects.

CONCLUSIONS

Our study showed no difference in short- or long-term pain in patients undergoing anterolateral thoracotomy or median sternotomy. Both groups showed a decrease in persistent postoperative pain incidence between 3 and 6 months without any significant changes at 12 months.

Seven-year follow-up of persistent postsurgical pain in cardiac surgery patients: A prospective observational study of prevalence and risk factors

BACKGROUND

Our aim was to describe the long-term prevalence, risk factors and impact on quality of life of persistent postsurgical pain (PPP) following cardiac surgery.

METHODS

All patients undergoing sternotomy in a single centre over 6 months were prospectively interviewed by telephone at six months and seven years following surgery.

RESULTS

We analysed data from 174 patients at six months and 146 patients at seven years following surgery, revealing a PPP prevalence of 39.7% (n = 69) and 9.6% (n = 14) respectively. At six post-operative months, younger age, higher acute pain score, intraoperative remifentanil infusion and more prolonged surgery were associated with sternotomy-site PPP. These variables, in combination, predict PPP in this study group with area under the receiver operating curve of 0.91 (95% CI 0.86-0.94) at 6 months and 0.74 (95% CI 0.57-0.86) at 7 years. Quality of life scores were significantly lower with PPP (median change in EQ-5D score = -0.23 [-0.57, -0.09] compared to 0.00 [0-0.24] without PPP at 7 years, p < 0.001). At7 years, younger age, prolonged surgery and intraoperative remifentanil infusion were associated with sternotomy-site PPP.

CONCLUSIONS

To the best of our knowledge, this is the longest follow-up of PPP across all surgical specialities and certainly within cardiac surgery. Prevalence of PPP and impact on QOL after cardiac surgery are high and associated with young age, high acute pain score, use of remifentanil and long operative time. We present a predictive score to highlight patients at risk of developing PPP.

SIGNIFICANCE

Seven years after cardiac surgery, almost 10% of patients in this cohort described persistent pain in and around the incision. While higher than previous reports in the literature (limited to up to five post-operative years), this assessment was made following three maximal coughs and therefore is movement or function evoked. High incident of persistent postsurgical pain may adversely affect long-term quality of life which is measured using a validated tool.

A Role for Transmembrane Protein 16C/Slack Impairment in Excitatory Nociceptive Synaptic Plasticity in the Pathogenesis of Remifentanil-induced Hyperalgesia in Rats

Remifentanil is widely used to control intraoperative pain. However, its analgesic effect is limited by the generation of postoperative hyperalgesia. In this study, we investigated whether the impairment of transmembrane protein 16C (TMEM16C)/Slack is required for α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic receptor (AMPAR) activation in remifentanil-induced postoperative hyperalgesia. Remifentanil anesthesia reduced the paw withdrawal threshold from 2 h to 48 h postoperatively, with a decrease in the expression of TMEM16C and Slack in the dorsal root ganglia (DRG) and spinal cord. Knockdown of TMEM16C in the DRG reduced the expression of Slack and elevated the basal peripheral sensitivity and AMPAR expression and function. Overexpression of TMEM16C in the DRG impaired remifentanil-induced ERK1/2 phosphorylation and behavioral hyperalgesia. AMPAR-mediated current and neuronal excitability were downregulated by TMEM16C overexpression in the spinal cord. Taken together, these findings suggest that TMEM16C/Slack regulation of excitatory synaptic plasticity via GluA1-containing AMPARs is critical in the pathogenesis of remifentanil-induced postoperative hyperalgesia in rats.

Influence of Levobupivacaine Regional Scalp Block on Hemodynamic Stability, Intra- and Postoperative Opioid Consumption in Supratentorial Craniotomies: A Randomized Controlled Trial

BACKGROUND

The anesthetic management of supratentorial craniotomy (CR) necessitates tight intraoperative hemodynamic control. This type of surgery may also be associated with substantial postoperative pain. We aimed at evaluating the influence of regional scalp block (SB) on hemodynamic stability during the noxious events of supratentorial craniotomies and total intravenous anesthesia, its influence on intraoperative anesthetic agents' consumption, and its effect on postoperative pain control.

METHODS

Sixty patients scheduled for elective CR were prospectively enrolled. Patient, anesthesiologist, and neurosurgeon were blind to the random performance of SB with either levobupivacaine 0.33% (intervention group [group SB], n = 30) or the same volume of saline (control group [group CO], placebo group, n = 30). General anesthesia was induced and maintained using target-controlled infusions of remifentanil and propofol that were adjusted according to hemodynamic parameters and state entropy of the electroencephalogram (SE), respectively. Mean arterial blood pressure (MAP), heart rate (HR), SE, and propofol and remifentanil effect-site concentrations (Ce) were recorded at the time of scalp block performance (Baseline), and 0, 1, 3, and 5 minutes after skull-pin fixation (SP), skin incision (SI), CR, and dura-mater incision (DM). Morphine consumption and postoperative pain intensity (0-10 visual analog scale [VAS]) were recorded 1, 3, 6, 24, and 48 hours after surgery. Propofol and remifentanil overall infusion rates were also recorded. Data were analyzed using 2-tailed Student unpaired t tests, 2-way mixed-design analysis of variance (ANOVA), and Tukey's honestly significant difference (HSD) tests for post hoc comparisons as appropriate.

RESULTS

Demographics and length of anesthetic procedure of group CO and SB were comparable. SP, SI, and CR were associated with a significantly higher MAP in group CO than in group SB, at least at one of the time points of recording surrounding those noxious events. This was not the case at DM. Similarly, HR was significantly higher in group CO than in group SB during SP and SI, at least at 1 of the points of recording, but not during CR and DM. Propofol and remifentanil Ce and overall infusion rates were significantly higher in group CO than in group SB, except for propofol Ce during SP. Postoperative pain VAS and cumulative morphine consumption were significantly higher in group CO than in group SB.

CONCLUSIONS

In supratentorial craniotomies, SB improves hemodynamic control during noxious events and provides adequate and prolonged postoperative pain control as compared to placebo.

Association Between Intraoperative Remifentanil Dosage and Postoperative Opioid Consumption in Adolescent Idiopathic Spine Surgery: A Retrospective Cohort Study

BACKGROUND

Adolescent idiopathic scoliosis (AIS) surgery is associated with significant postoperative pain. Remifentanil is a short-acting opioid that is often used as a component of total intravenous anesthesia. Remifentanil has been implicated in acute opioid tolerance and opioid-induced hyperalgesia, resulting in increased postoperative pain and opioid consumption. This retrospective study sought to investigate the relationship between the dose of intraoperative remifentanil and cumulative postoperative opioid consumption through 72 hours following surgery for pediatric AIS patients.

METHODS

We performed a retrospective chart review of adolescent patients undergoing posterior spine instrumentation under total intravenous general anesthesia at a single major pediatric center between January 2015 and October 2017. The relationship between intraoperative cumulative weight-adjusted remifentanil dose and logarithmic transformation of cumulative weight-adjusted opioid consumption through 72 hours following surgery was examined by regression analysis. A priori determined potential confounding variables were collected, including demographic data, perioperative analgesic agents (ie, ketamine, dexmedetomidine, and acetaminophen), surgical duration, vertebrae instrumented, and blood transfusion. Multivariable linear regression analysis was used to adjust for these possible confounding variables.

RESULTS

Eighty-nine patients met inclusion criteria, of which 78 had complete data for analysis. Univariable linear regression analysis revealed no association between remifentanil dose and opioid consumption through 72 hours following surgery (slope = 0.79 [95% confidence interval [CI], 0.61-0.98; R2 = 0.0039; P = .588]). After adjustment for possible confounding factors, no relationship between remifentanil dose (regression coefficient (coeff.) -0.08; 95% CI, -1.59 to 1.43; P = .912) and opioid consumption through 72 hours was found (slope =0.90 [95% CI, -0.65 to 2.46]; R2 = 0.1634). Similar results were obtained when the model was repeated for opioid consumption in postanesthesia care unit (PACU).

CONCLUSIONS

In this study examining adolescent patients undergoing surgery for idiopathic scoliosis, no association was found between the dose of intraoperative remifentanil and postoperative opioid consumption in the context of a propofol-based total intravenous anesthetic and multimodal analgesia. These results provide direction for future prospective controlled studies to further evaluate this relationship.

The role of regional anaesthesia and multimodal analgesia in the prevention of chronic postoperative pain: a narrative review

Effective prevention of chronic postoperative pain is an important clinical goal, informed by a growing body of studies. Peri-operative regional anaesthesia remains one of the most important tools in the multimodal analgesic toolbox, blocking injury-induced activation and sensitisation of both the peripheral and central nervous system. We review the definition and taxonomy of chronic postoperative pain, its mechanistic basis and the most recent evidence for the preventative potential of multimodal analgesia, with a special focus on regional anaesthesia. While regional anaesthesia targets several important aspects of the mechanistic pathway leading to chronic postoperative pain, evidence for its efficacy is still mixed, possibly owing to the heterogeneity of risk profiles within the surgical patient, but also to variation in techniques and medications reported in the literature.

Intraoperative Remifentanil Infusion and Postoperative Pain Outcomes After Cardiac Surgery-Results from Secondary Analysis of a Randomized, Open-Label Clinical Trial

DESIGN

Report of secondary pain outcomes from a prospective, randomized, open-label clinical trial that compared remifentanil and fentanyl on perioperative hyperglycemic response in cardiac surgery.

SETTING

Single institution, tertiary university hospital.

PARTICIPANTS

The study comprised 116 adult elective cardiac surgical patients.

INTERVENTIONS

Participants were randomly assigned to receive either intermittent fentanyl boluses (F) or continuous remifentanil infusion (R) intraoperatively.

MEASUREMENTS AND MAIN RESULTS

Postoperative pain was evaluated with pain scores every 6 hours for 48 hours. Pain threshold to mechanical stimuli was measured around the sternotomy incision at 48 and 96 hours. The development of chronic pain was assessed using the numeric rating scale at 1, 3, 6, and 12 months after discharge. The final analysis included 106 patients. Pain scores and wound hyperalgesia were not significantly different postoperatively between the groups. The incidence of chronic pain at 3 months was comparable in both groups (61% in group F v 58% in group R; p = 0.79). Pain of more-than-mild degree was seen in 13 (32%) patients in group F and 8 (19%) in group R (p = 0.25) at 3 months. Median pain scores were not significantly different between the groups at 1, 3, 6, and 12 months after discharge from the hospital.

CONCLUSIONS

The present study's findings suggested that intraoperative remifentanil infusion does not significantly worsen pain outcomes in patients undergoing elective cardiac surgery.

A Neurobehavioral Approach to Addiction: Implications for the Opioid Epidemic and the Psychology of Addiction

Two major questions about addictive behaviors need to be explained by any worthwhile neurobiological theory. First, why do people seek drugs in the first place? Second, why do some people who use drugs seem to eventually become unable to resist drug temptation and so become "addicted"? We will review the theories of addiction that address negative-reinforcement views of drug use (i.e., taking opioids to alleviate distress or withdrawal), positive-reinforcement views (i.e., taking drugs for euphoria), habit views (i.e., growth of automatic drug-use routines), incentive-sensitization views (i.e., growth of excessive "wanting" to take drugs as a result of dopamine-related sensitization), and cognitive-dysfunction views (i.e., impaired prefrontal top-down control), including those involving competing neurobehavioral decision systems (CNDS), and the role of the insula in modulating addictive drug craving. In the special case of opioids, particular attention is paid to whether their analgesic effects overlap with their reinforcing effects and whether the perceived low risk of taking legal medicinal opioids, which are often prescribed by a health professional, could play a role in the decision to use. Specifically, we will address the issue of predisposition or vulnerability to becoming addicted to drugs (i.e., the question of why some people who experiment with drugs develop an addiction, while others do not). Finally, we review attempts to develop novel therapeutic strategies and policy ideas that could help prevent opioid and other substance abuse.

Morpheus and the Underworld-Interventions to Reduce the Risks of Opioid Use After Surgery: ORADEs, Dependence, Cancer Progression, and Anastomotic Leakage

BACKGROUND

Perioperative pain management is a key element of enhanced recovery after surgery (ERAS) programs. A multimodal approach to analgesia as part of a coordinated ERAS includes the reduction of opioid use. This review aims to discuss opioid-related adverse events, strategies to reduce opioid use after surgery, and the relevance to the present "opioid crisis" in North America.

METHODS

A literature review of the pharmacology of opioid drugs, perioperative opioid reduction strategies, and the potential public health benefit was performed. This included current ERAS guidelines on multimodal analgesia, randomized controlled trials on perioperative analgesia, and intervention studies to decrease opioid use, misuse, and diversion in North America.

RESULTS

Reduction of perioperative opioid usage has been endorsed by joint clinical practice guidelines on the management of postoperative pain from the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists. Interventions as part of an "opioid bundle" that can be incorporated into ERAS protocols include multimodal analgesia, regional anesthesia, opioid sparing drugs, carbon dioxide humidification during laparoscopy, changing opioid prescription practices, patient and physician education, and proper disposal of unused opioid medications.

CONCLUSION

There are substantial benefits in incorporating opioid reduction strategies into ERAS and clinical practice guidelines. These include faster return of function and mobility, and decreased opioid-related adverse drug events (ORADEs), postoperative morbidity and mortality, and length of hospital stay. Improved oncological outcomes after cancer surgery may be an additional benefit. Evidence-based interventions can also reduce opioid abuse and diversion in the community.

Short- and long-term impact of remifentanil on thermal detection and pain thresholds after cardiac surgery: A randomised controlled trial

BACKGROUND

The clinical relevance of the suggested hyperalgesic effects of remifentanil is still unclear, especially in the long term.

OBJECTIVE

The current study evaluated the impact of remifentanil on thermal thresholds 3 days and 12 months after surgery, measured with Quantitative Sensory Testing.

DESIGN

A single-blind, randomised controlled trial.

SETTING

A tertiary care teaching hospital in The Netherlands, from 2014 to 2016.

PATIENTS

A total of 126 patients aged between 18 and 85 years, undergoing cardiothoracic surgery via sternotomy (coronary artery bypass grafts and/or valve replacement) were included. Exclusion criteria were BMI above 35 kg m, history of cardiac surgery, chronic pain conditions, neurological conditions, allergy to opioids or paracetamol, language barrier and pregnancy.

INTERVENTIONS

Patients were allocated randomly to receive intra-operatively either a continuous remifentanil infusion or intermittent intra-operative fentanyl as needed in addition to standardised anaesthesia with propofol and intermittent intravenous fentanyl at predetermined time points.

MAIN OUTCOME MEASURES

Warm and cold detection and pain thresholds 3 days and 12 months after surgery. In addition the use of remifentanil, presence of postoperative chronic pain, age, opioid consumption and pre-operative quality of life were tested as a predictor for altered pain sensitivity 12 months after surgery.

RESULTS

Both warm and cold detection, and pain thresholds, were not significantly different between the remifentanil and fentanyl groups 3 days and 12 months after surgery (P > 0.05). No significant predictors for altered pain sensitivity were identified.

CONCLUSION

Earlier reports of increased pain sensitivity 1 year after the use of remifentanil could not be confirmed in this randomised study using Quantitative Sensory Testing. This indicates that remifentanil plays a minor role in the development of chronic thoracic pain. Still, the relatively high incidence of chronic thoracic pain and its accompanying impact on quality of life remain challenging problems.

TRIAL REGISTRATION

The study was registered at EudraCT (ref: 2013-000201-23) and ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT02031016).

Perioperative opioid analgesia-when is enough too much? A review of opioid-induced tolerance and hyperalgesia

Opioids are a mainstay of acute pain management but can have many adverse effects, contributing to problematic long-term use. Opioid tolerance (increased dose needed for analgesia) and opioid-induced hyperalgesia (paradoxical increase in pain with opioid administration) can contribute to both poorly controlled pain and dose escalation. Hyperalgesia is particularly problematic as further opioid prescribing is largely futile. The mechanisms of opioid tolerance and hyperalgesia are complex, involving μ opioid receptor signalling pathways that offer opportunities for novel analgesic alternatives. The intracellular scaffold protein β-arrestin-2 is implicated in tolerance, hyperalgesia, and other opioid side-effects. Development of agonists biased against recruitment of β-arrestin-2 could provide analgesic efficacy with fewer side-effects. Alternative approaches include inhibition of peripheral μ opioid receptors and blockade of downstream signalling mechanisms, such as the non-receptor tyrosine kinase Src or N-methyl-D-aspartate receptors. Furthermore, it is prudent to use multimodal analgesic regimens to reduce reliance on opioids during the perioperative period. In the third paper in this Series we focus on clinical and mechanism-based understanding of tolerance and opioid-induced hyperalgesia, and discuss current and future strategies for pain management.

Intranasal Low-Dose Dexmedetomidine Reduces Postoperative Opioid Requirement in Patients Undergoing Hip Arthroplasty Under General Anesthesia

BACKGROUND

Patients undergoing total hip arthroplasty (THA) need substantial amount of opioids for postoperative pain management, which necessitates opioid-sparing modalities. Dexmedetomidine is a novel alpha-2-adrenoceptor-activating drug for procedural sedation. In addition to its sedative effect, dexmedetomidine has analgesic and antiemetic effects. We evaluated retrospectively the effect of intraoperatively administered intranasal low-dose dexmedetomidine on postoperative opioid requirement in patients undergoing THA.

METHODS

We included 120 patients with American Society of Anesthesiologists status 1-2, age between 35 and 80 years, and scheduled for unilateral primary THA under general anesthesia with total intravenous anesthesia. Half of the patients received 50 μg of intranasal dexmedetomidine after anesthesia induction, while the rest were treated conventionally. Postoperative opioid requirements were calculated as morphine equivalent doses for both groups. The impact of intranasal dexmedetomidine on postoperative hemodynamics and length of stay was evaluated.

RESULTS

The cumulative postoperative opioid requirement was significantly reduced in the dexmedetomidine group compared with the control group (26.3 mg, 95% confidence interval 15.6-36.4, P < .001). The cumulative dose was significantly different between the groups already at 12, 24, and 36 h postoperatively (P = .01; P = .001; P < .001, respectively). Dexmedetomidine group had lower mean arterial pressure in the postanesthesia care unit compared with the control group (P = .01). There was no difference in the postanesthesia care unit stay or postoperative length of stay between the two groups (P = .47; P = .10, respectively).

CONCLUSION

Compared with the control group, intraoperative use of intranasal low-dose dexmedetomidine decreases opioid consumption and sympathetic response during acute postoperative period in patients undergoing THA.

Managing Prolonged Pain After Surgery: Examining the Role of Opioids

A notable minority of patients experience persistent postsurgical pain and some of these patients consequently have prolonged exposure to opioids. Risk factors for prolonged opioid use after surgery include preoperative opioid use, anxiety, substance abuse, and alcohol abuse. The window to intervene and potentially prevent persistent opioid use after surgery is short and may best be accomplished by both surgeon and anesthesiologist working together. Anesthesiologists in particular are well positioned in the perioperative surgical home model to affect multiple aspects of the perioperative experience, including tailoring intraoperative medications and providing consultation for possible discharge analgesic regimens that can help minimize opioid use. Multimodal analgesia protocols reduce opioid consumption and thereby reduce exposure to opioids and theoretically the risk of persistent use. Regional anesthesia and analgesia techniques also reduce opioid consumption. Although many patients will recover without difficulty, the small minority who do not should receive customized care which may involve multiple office visits or consultation of a pain specialist. Enhanced recovery pathways are useful in optimizing outcomes after surgery.

Persistent Postsurgical Pain

The development of chronic pain is considered a major complication after surgery. Basic science research in animal models helps us understand the transition from acute to chronic pain by identifying the numerous molecular and cellular changes that occur in the peripheral and central nervous systems. It is now well recognized that inflammation and nerve injury lead to long-term synaptic plasticity that amplifies and also maintains pain signaling, a phenomenon referred to as pain sensitization. In the context of surgery in humans, pain sensitization is both responsible for an increase in postoperative pain via the expression of wound hyperalgesia and considered a critical factor for the development of persistent postsurgical pain. Using specific drugs that block the processes of pain sensitization reduces postoperative pain and prevents the development of persistent postoperative pain. This narrative review of the literature describes clinical investigations evaluating different preventative pharmacologic strategies that are routinely used by anesthesiologists in their daily clinical practices for preventing persistent postoperative pain. Nevertheless, further efforts are needed in both basic and clinical science research to identify preclinical models and novel therapeutics targets. There remains a need for more patient numbers in clinical research, for more reliable data, and for the development of the safest and the most effective strategies to limit the incidence of persistent postoperative pain.

Spinal Protein Kinase Mζ Regulates α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptor Trafficking and Dendritic Spine Plasticity via Kalirin-7 in the Pathogenesis of Remifentanil-induced Postincisional Hyperalgesia in Rats

Background

Intraoperative remifentanil anesthesia exaggerates postoperative pain sensitivity. Recent studies recapitulate the significance of protein kinase Mζ in α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor–mediated pathologic pain. Kalirin-7, a Rho guanine nucleotide exchange factor, coordinates AMPA receptor trafficking and dendritic spine plasticity. This study examines whether protein kinase Mζ and Kalirin-7 contribute to remifentanil-induced postincisional hyperalgesia via AMPA receptor.

Methods

Plantar incision was performed 10 min after the start of remifentanil infusion (1 µg · kg−1 · min−1 for 60 min). Paw withdrawal threshold (primary outcome), spinal protein kinase Mζ activity, Kalirin-7 expression, AMPA receptor trafficking, and spine morphology were assessed. Protein kinase Mζ inhibitor and Kalirin-7 knockdown by short hairpin RNA elucidated the mechanism and prevention of hyperalgesia. Whole-cell patch-clamp recording analyzed the role of protein kinase Mζ in spinal AMPA receptor–induced current.

Results

Remifentanil reduced postincisional paw withdrawal threshold (mean ± SD, control vs. hyperalgesia, 18.9 ± 1.6 vs. 5.3 ± 1.2 g, n = 7) at postoperative 48 h, which was accompanied by an increase in spinal protein kinase Mζ phosphorylation (97.8 ± 25.1 vs. 181.5 ± 18.3%, n = 4), Kalirin-7 production (101.9 ± 29.1 vs. 371.2 ± 59.1%, n = 4), and number of spines/10 µm (2.0 ± 0.3 vs. 13.0 ± 1.6, n = 4). Protein kinase Mζ inhibitor reduced remifentanil-induced hyperalgesia, Kalirin-7 expression, and GluA1 trafficking. Incubation with protein kinase Mζ inhibitor reversed remifentanil-enhanced AMPA receptor-induced current in dorsal horn neurons. Kalirin-7 deficiency impaired remifentanil-caused hyperalgesia, postsynaptic GluA1 insertion, and spine plasticity. Selective GluA2-lacking AMPA receptor antagonist prevented hyperalgesia in a dose-dependent manner.

Conclusions

Spinal protein kinase Mζ regulation of GluA1-containing AMPA receptor trafficking and spine morphology via Kalirin-7 overexpression is a fundamental pathogenesis of remifentanil-induced hyperalgesia in rats.

Effects of remifentanil versus nitrous oxide on postoperative nausea, vomiting, and pain in patients receiving thyroidectomy: Propensity score matching analysis

Remifentanil and nitrous oxide (N2O) are 2 commonly used anesthetic agents. Both these agents are known risk factors for postoperative nausea and vomiting (PONV). However, remifentanil and N2O have not been directly compared in a published study. Remifentanil can induce acute tolerance or hyperalgesia, thus affecting postoperative pain. The objective of this retrospective study is to compare the effects of remifentanil and N2O on PONV and pain in patients receiving intravenous patient-controlled analgesia (IV-PCA) after thyroidectomy.We analyzed the electronic medical records of 992 patients receiving fentanyl-based IV-PCA after thyroidectomy at Chung-Ang University Hospital from January 1, 2010 to April 30, 2016. We categorized the patients according to anesthetic agents used: group N2O (n = 745) and group remifentanil (n = 247). The propensity score matching method was used to match patients in the 2 groups based on their covariates. Finally, 128 matched subjects were selected from each group.There were no differences between groups for all covariates after propensity score matching. The numeric rating scale for nausea (0.55 ± 0.88 vs 0.27 ± 0.76, P = 0.01) was higher and complete response (88 [68.8%] vs 106 [82.8%], P = 0.001) was lower in group N2O compared with group remifentanil on postoperative day 0. However, the visual analog scale score for pain (3.47 ± 2.02 vs 3.97 ± 1.48, P = 0.025) was higher in group remifentanil than group N2O on postoperative day 0.In patients receiving IV-PCA after thyroidectomy, postoperative nausea was lower but postoperative pain was higher in group remifentanil.

Pharmacological sedation management in the paediatric intensive care unit

Objective

This review addresses sedation management on paediatric intensive care units and possible gaps in the knowledge of optimal sedation strategies. We present an overview of the commonly used sedatives and their pharmacokinetic and pharmacodynamic considerations in children, as well as the ongoing studies in this field. Also, sedation guidelines and current sedation strategies and assessment methods are addressed.

Key findings

This review shows that evidence and pharmacokinetic data are scarce, but fortunately, there is an active research scene with promising new PK and PD data of sedatives in children using new study designs with application of advanced laboratory methods and modelling. The lack of evidence is increasingly being recognized by authorities and legislative offices such as the US Food and Drug Administration (FDA) and European Medicines Agency (EMA).

Conclusion

The population in question is very heterogeneous and this overview can aid clinicians and researchers in moving from practice-based sedation management towards more evidence- or model-based practice. Still, paediatric sedation management can be improved in other ways than pharmacology only, so future research should aim on sedation assessment and implementation strategies of protocolized sedation as well.