Remifentanil for general anaesthesia: a systematic review

Hypotension after general anaesthesia induction using remimazolam or propofol in geriatric patients undergoing sevoflurane anaesthesia with remifentanil: a single-centre, double-blind, randomised controlled trial

BACKGROUND

The occurrence of hypotension after induction of general anaesthesia is common in geriatric patients, and should be prevented to minimise perioperative complications. Compared with propofol, remimazolam potentially has a lower incidence of hypotension. This study aimed to compare the incidence of hypotension after general anaesthesia induction with remimazolam or propofol in geriatric patients.

METHODS

This single-centre, double-blind, randomised trial enrolled 90 patients aged ≥80 yr who received general anaesthesia for scheduled surgery. Patients were randomised to receive remimazolam (12 mg kg-1 h-1) or propofol (0.025 mg kg-1 s-1) for anaesthesia induction, with remifentanil and sevoflurane. The presence or absence of hypertension on the ward served as the stratification factor. The incidence of hypotension after the induction of general anaesthesia, defined as a noninvasive mean arterial pressure of <65 mm Hg measured every minute from initiation of drug administration to 3 min after tracheal intubation, was the primary outcome. Subgroup analysis was performed for the primary outcome using preoperative ward hypertension, clinical frailty scale, Charlson Comorbidity Index, and age.

RESULTS

Three subjects were excluded before drug administration, and 87 subjects were included in the analysis. The incidence of hypotension was 72.1% (31/43) and 72.7% (32/44) with remimazolam or propofol, respectively. No statistically significant differences (adjusted odds ratio, 0.96; 95% confidence interval, 0.37-2.46; P=0.93) were observed between groups. Subgroup analysis revealed no significant differences between groups.

CONCLUSIONS

Compared with propofol, remimazolam did not reduce the incidence of hypotension after general anaesthesia induction in patients aged ≥80 yr.

CLINICAL TRIAL REGISTRATION

UMIN000042587.

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.

Perioperative adverse cardiac events in maxillofacial surgery: A systematic review and meta-analysis

Background and Aims

Maxillofacial surgeries, including procedures to the face, oral cavity, jaw, and head and neck, are common in adults. However, they impose a risk of adverse cardiac events (ACEs). While ACEs are well understood for other non-cardiac surgeries, there is a paucity of data about maxillofacial surgeries. This systematic review and meta-analysis report the incidence and presentation of perioperative ACEs during maxillofacial surgery.

Methods

We included primary studies that reported on perioperative ACEs in adults. To standardise reporting, ACEs were categorised as 1. heart rate and rhythm disturbances, 2. blood pressure disturbances, 3. ischaemic heart disease and 4. heart failure and other complications. The primary outcome was ACE presentation and incidence during the perioperative period. Secondary outcomes included the surgical outcome according to the Clavien-Dindo classification and trigeminocardiac reflex involvement. STATA version 17.0 and MetaProp were used to delineate proportion as effect size with a 95% confidence interval (CI).

Results

Twelve studies (34,227 patients) were included. The incidence of perioperative ACEs was 2.58% (95% CI 1.70, 3.45, I2 = 96.17%, P = 0.001). Heart rate and rhythm disturbances resulted in the greatest incidence at 3.84% among the four categories. Most commonly, these ACEs resulted in intensive care unit admission (i.e. Clavien-Dindo score of 4).

Conclusion

Despite an incidence of 2.58%, ACEs can disproportionately impact surgical outcomes. Future research should include large-scale prospective studies that may provide a better understanding of the contributory factors and long-term effects of ACEs in patients during maxillofacial surgery.

Postoperative pain at Landspitali: A prospective study

BACKGROUND

Moderate or severe postoperative pain is common despite advances in surgical technique and perioperative analgesia. This study aimed to assess the prevalence and severity of postoperative pain following procedures requiring anaesthesia and identify factors associated with increased risk of postoperative pain.

METHODS

Surgical patients ≥18 years of age were prospectively questioned on level of current pain on a numerical rating scale (NRS) from 0 to 10 in the post-anaesthesia care unit (PACU) and on resting, active and worst pain experienced in the first 24 h postoperatively. Clinical data was obtained from medical records. Descriptive statistics were applied, and predictors of worst pain assessed as moderate/severe (NRS≥ $$ \ge $$ 5) on postoperative day one were assessed using multivariable logistic regression.

RESULTS

Of 438 included participants, moderate/severe pain occurred in 29% on the day of surgery and 70% described their worst pain as moderate/severe on postoperative day one. Procedures with the highest incidence of moderate/severe pain on the day of surgery were gynaecology-, plastic-, abdominal-, breast-, and orthopaedic procedures. On postoperative day one, patients undergoing vascular-, orthopaedic-, and abdominal operations most commonly rated their worst pain as moderate/severe. Female sex (OR = 2.15, 95% Cl 1.21-3.88, p = .010), chronic preoperative pain (OR = 4.20, 95% Cl 2.41-7.51, p < .001), undergoing a major procedure (OR = 2.07, 95% Cl 1.15-3.80, p = .017), and any intraoperative remifentanil administration (OR = 2.16, 95% Cl 1.20-3.94, p = .01) had increased odds of rating the worst pain as moderate/severe. Increased age (OR = 0.66 per 10 years (95% Cl 0.55-0.78, p < .001)) and undergoing breast-, gynaecology-, otolaryngology-, and neurosurgery (OR = 0.15-0.34, p < .038) was associated with lower odds of moderate/severe pain on postoperative day one.

DISCUSSION

In our cohort, patients rated their current pain in the PACU similarly to other studies. However, the ratio of patients rating the worst pain experienced as moderate/severe on postoperative day one was relatively high. The identified patient- and procedural-related factors associated with higher odds of postoperative pain highlight a subgroup of patients who may benefit from enhanced perioperative monitoring and pain management strategies.

Effect of opioid-free versus opioid-based strategies during multimodal anaesthesia on postoperative morphine consumption after bariatric surgery: a randomised double-blind clinical trial

Background

The efficacy and safety of opioid-free anaesthesia during bariatric surgery remain debated, particularly when administering multimodal analgesia. As multimodal analgesia has become the standard of care in many centres, we aimed to determine if such a strategy coupled with either dexmedetomidine (opioid-free anaesthesia) or remifentanil with a morphine transition (opioid-based anaesthesia), would reduce postoperative morphine requirements and opioid-related adverse events.

Methods

In this prospective double-blind study, 172 class III obese patients having laparoscopic gastric bypass surgery were randomly allocated to receive either sevoflurane-dexmedetomidine anaesthesia with a continuous infusion of lidocaine and ketamine (opioid-free group) or sevoflurane-remifentanil anaesthesia with a morphine transition (opioid-based group). Both groups received at anaesthesia induction a bolus of magnesium, lidocaine, ketamine, paracetamol, diclofenac, and dexamethasone. The primary outcome was 24-h postoperative morphine consumption. Secondary outcomes included postoperative quality of recovery (QoR40), incidence of hypoxaemia, bradycardia, and postoperative nausea and vomiting (PONV).

Results

Eighty-six patients were recruited in each group (predominantly women, 70% had obstructive sleep apnoea). There was no significant difference in postoperative morphine consumption (median [inter-quartile range]: 16 [13-26] vs 15 [10-24] mg, P=0.183). The QoR40 up to postoperative day 30 did not differ between groups, but PONV was less frequent in the opioid-free group (37% vs 59%, P=0.005). Hypoxaemia and bradycardia were not different between groups.

Conclusions

During bariatric surgery, a multimodal opioid-free anaesthesia technique did not decrease postoperative morphine consumption when compared with a multimodal opioid-based strategy. Quality of recovery did not differ between groups although the incidence of PONV was less in the opioid-free group.

Clinical trial registration

NCT05004519.

Remifentanil for tracheal intubation without neuromuscular blocking drugs in adult patients: a systematic review and meta-analysis

There is increasing interest in the use of short-acting opioids such as remifentanil to facilitate tracheal intubation. The aim of this systematic review was to determine the efficacy and safety of remifentanil for tracheal intubation compared with neuromuscular blocking drugs in adult patients. We conducted a systematic search for randomised controlled trials evaluating remifentanil for tracheal intubation. Primary outcomes included tracheal intubation conditions and adverse events. Twenty-one studies evaluating 1945 participants were included in the analysis. Use of remifentanil (1.5-4.0 μg.kg-1 ) showed no evidence of a difference in tracheal intubation success rate compared with neuromuscular blocking drugs (risk ratio (95%CI) 0.97 (0.94-1.01); six studies; 1232 participants; I2 28%; p = 0.16; moderate-certainty evidence). Compared with neuromuscular blocking drugs, the use of remifentanil (2.0-4.0 μg.kg-1 ) makes little to no difference in terms of producing excellent tracheal intubation conditions (risk ratio (95%CI) 1.16 (0.72-1.87); two studies; 121 participants; I2 31%, p = 0.54; moderate-certainty of evidence). There was no evidence of an effect between remifentanil (2.0-4.0 μg.kg-1 ) and neuromuscular blocking drugs for bradycardia (risk ratio (95%CI) 0.44 (0.01-13.90); two studies; 997 participants; I2 81%; p = 0.64) and hypotension (risk ratio (95%CI) 1.05 (0.44-2.49); three studies; 1071 participants; I2 92%; p = 0.92). However, the evidence for these two outcomes was judged to be of very low-certainty. We conclude that remifentanil may be used as an alternative drug for tracheal intubation in cases where neuromuscular blocking drugs are best avoided, but more studies are required to evaluate the haemodynamic adverse events of remifentanil at different doses.

Efficacy, safety, and pharmacokinetics of MR13A11A, a generic of remifentanil, for pain management of Japanese patients in the intensive care unit: a double-blinded, fentanyl-controlled, randomized, non-inferiority phase 3 study

BACKGROUND

The aims of this study were to evaluate the efficacy, safety, and pharmacokinetics (PK) of continuous intravenous administration of remifentanil in mechanically ventilated patients in the intensive care unit (ICU).

METHODS

This was a multicenter, randomized, double-blinded, fentanyl-controlled, non-inferiority phase 3 study. Patients aged ≥ 20 years requiring 6 h to 10 days mechanical ventilation in an ICU and requiring pain relief were randomly assigned in a 1:1 ratio to receive either remifentanil (n = 98) or fentanyl (n = 98). Dose was titrated from an infusion rate of 1 mL/h (remifentanil: 0.025 µg/kg/min, fentanyl: 0.1 µg/kg/h) until the target level of analgesia (behavioral pain scale [BPS] ≤ 5 or numerical rating score [NRS] ≤ 3) was achieved by escalating the dose in 1 mL/h increasing. Administration was then adjusted to maintain the target level of analgesia until weaning from the ventilator. The primary endpoint was the proportion of patients who did not require rescue fentanyl. Safety was assessed according to standard procedures. PK of remifentanil in the arterial blood was assessed in 24 patients.

RESULTS

The proportion of patients achieving the primary endpoint in the remifentanil and fentanyl groups was 100% (92/92) and 97.8% (88/90), respectively. The difference between the groups was 2.2% (95% confidence interval, - 0.8-5.3) and non-inferiority of remifentanil to fentanyl was verified (p < 0.0001). The incidences of any adverse events in the remifentanil and fentanyl groups was 34 of 92 patients (37.0%) and 34 of 90 patients (37.8%), respectively. Adverse drug reactions was 12 in 92 patients (13.0%) and 15 in 90 patients (16.7%), respectively. In the PK analysis, blood remifentanil concentration decreased within 10 min to almost 50% of the end of administration, suggesting rapid offset of action following discontinuation of remifentanil.

CONCLUSIONS

Remifentanil can be used safely for pain management in mechanically ventilated Japanese patients in the ICU.

TRIAL REGISTRATION

Japan Registry of Clinical Trials, jRCT2080224954. Registered 20 November 2019, https://jrct.niph.go.jp/latest-detail/jRCT2080224954 .

Pharmacodynamic mechanism-based interaction model for the haemodynamic effects of remifentanil and propofol in healthy volunteers

BACKGROUND

Propofol and remifentanil are frequently combined for the induction and maintenance of general anaesthesia. Both propofol and remifentanil cause vasodilation and potentially reduce arterial BP. We aimed to develop a mechanism-based model that characterises the haemodynamic interactions between remifentanil and propofol.

METHODS

Data from two clinical trials in healthy volunteers were analysed using remifentanil-alone, propofol-alone, and combination groups. We evaluated remifentanil effects on haemodynamics using a previously developed mechanism-based haemodynamic model of propofol. The interaction between propofol and remifentanil was explored using the principles of the general pharmacodynamic interaction (GPDI) model.

RESULTS

Remifentanil alone increased the dissipation rate of total peripheral resistance by 50% at 3.0 ng ml-1. Additionally, the dissipation rates of HR and stroke volume were attenuated by 4.8% and 4.9% per 1 ng ml-1 increase in remifentanil concentration, respectively. The maximal effect of propofol alone in decreasing the production rate of total peripheral resistance was 78%, which decreased to 32% when combined with remifentanil 4 ng ml-1. The effects of remifentanil on HR and stroke volume were attenuated by propofol with maximum decreases of 11.9% and 21.2%, respectively. Goodness-of-fit plots and prediction-corrected visual predictive check plots showed good predictive performance of the models.

CONCLUSIONS

The structure of the previous mechanism-based haemodynamic model for propofol was able to describe the effects of remifentanil alone on haemodynamic variables. The GPDI model provided a good framework for characterising the pharmacodynamic interaction between remifentanil and propofol on haemodynamic properties.

CLINICAL TRIAL REGISTRATION

NCT02043938; NCT03143972.

Comparison of the perfusion index as an index of noxious stimulation in monitored anesthesia care of propofol/remifentanil and propofol/dexmedetomidine: a prospective, randomized, case-control, observational study

BACKGROUND

Dexmedetomidine, one of the sedatives, has an analgesic effect. We aimed to investigate postoperative analgesia with dexmedetomidine as adjuvants for procedural sedation using perfusion index (PI).

METHODS

In this prospective, randomized, case-control, observational study, 72 adult patients, 19-70 years, who were scheduled for chemoport insertion under monitored anesthesia care were performed. According to the group assignment, remifentanil or dexmedetomidine was simultaneously infused with propofol. The primary outcome was PI 30 min after admission to the post anesthesia care unit (PACU). And, pain severity using numerical rating scale (NRS) score and the relationship between NRS score and PI were investigated.

RESULTS

During PACU staying, PI values were significantly different between the two groups PI values at 30 min after admission to the PACU were 1.3 (0.9-2.0) in the remifentanil group and 4.5 (2.9-6.8) in the dexmedetomidine group (median difference, 3; 95% CI, 2.1 to 4.2; P < 0.001). The NRS scores at 30 min after admission to the PACU were significantly lower in the dexmedetomidine group (P = 0.002). However, there was a weak positive correlation between NRS score and PI in the PACU (correlation coefficient, 0.188; P = 0.01).

CONCLUSION

We could not find a significant correlation between PI and NRS score for postoperative pain control. Using PI as a single indicator of pain is insufficient.

TRIAL REGISTRATION

Clinical Trial Registry of Korea, https://cris.nih.go.kr : KCT0003501, the date of registration: 13/02/2019.

Combined use of intraoperative MRI and awake tailored microsurgical resection to respect functional neural networks: preliminary experience

INTRODUCTION

The combined use of intraoperative MRI and awake surgery is a tailored microsurgical resection to respect functional neural networks (mainly the language and motor ones). Intraoperative MRI has been classically considered to increase the extent of resection for gliomas, thereby reducing neurological deficits. Herein, we evaluated the combined technique of awake microsurgical resection and intraoperative MRI for primary brain tumours (gliomas, metastasis) and epilepsy (cortical dysplasia, non-lesional, cavernomas).

PATIENTS AND METHODS

Eighteen patients were treated with the commonly used "asleep awake asleep" (AAA) approach at Lille University Hospital, France, from November 2016 until May 2020. The exact anatomical location was insular with various extensions, frontal, temporal or fronto-temporal in 8 (44.4%), parietal in 3 (16.7%), fronto-opercular in 4 (22.2%), Rolandic in two (11.1%), and the supplementary motor area (SMA) in one (5.6%).

RESULTS

The patients had a mean age of 38.4 years (median 37.1, range 20.8-66.9). The mean surgical duration was 4.1 hours (median 4.2, range 2.6-6.4) with a mean duration of intraoperative MRI of 28.8 minutes (median 25, range 13-55). Overall, 61% (11/18) of patients underwent further resection, while 39% had no additional resection after intraoperative MRI. The mean preoperative and postoperative tumour volumes of the primary brain tumours were 34.7 cc (median 10.7, range 0.534-130.25) and 3.5 cc (median 0.5, range 0-17.4), respectively. Moreover, the proportion of the initially resected tumour volume at the time of intraoperative MRI (expressed as 100% from preoperative volume) and the final resected tumour volume were statistically significant (p= 0.01, Mann-Whitney test). The tumour remnants were commonly found posterior (5/9) or anterior (2/9) insular and in proximity with the motor strip (1/9) or language areas (e.g. Broca, 1/9). Further resection was not required in seven patients because there were no remnants (3/7), cortical stimulation approaching eloquent areas (3/7) and non-lesional epilepsy (1/7). The mean overall follow-up period was 15.8 months (median 12, range 3-36).

CONCLUSION

The intraoperative MRI and awake microsurgical resection approach is feasible with extensive planning and multidisciplinary collaboration, as these methods are complementary and synergic rather than competitive to improve patient oncological outcomes and quality of life.

Comparison of Dexmedetomidine Versus Fentanyl-Based Anesthetic Protocols Under Patient State Index Guidance in Patients Undergoing Elective Neurosurgical Procedures with Intraoperative Neurophysiological Monitoring

Objectives The study was designed to elucidate the effects of dexmedetomidine as an anesthetic adjunct to propofol in total intravenous anesthesia (TIVA) on anesthetic dose reduction, the quality of intraoperative neurophysiological monitoring (IONM) recordings, analgesic requirements, and recovery parameters in patients undergoing neurosurgical procedures with neurophysiological monitoring. Methods A total of 54 patients for elective neurosurgical procedures with IONM were randomized to group D (dexmedetomidine) and group F (fentanyl). A loading dose of the study drug of 1µg/kg followed by 0.5 µg/kg/h infusion was used in two groups. Propofol-based TIVA with a Schneider target-controlled infusion model was used for induction and maintenance with effect site concentration of 4-5 and 2.5-4 µg/mL, respectively, titrated to a Patient State Index (PSI) of 25-40. Baseline IONM recordings were obtained after induction. The mean propofol consumption, number of patient movements, quality of IONM recordings, number of fentanyl boluses, hemodynamic characteristics, and recovery parameters were recorded. Results The mean propofol consumption was significantly lower in group D when compared to group F (101.4 ± 13.5 µg/kg/min vs 148.0 ± 29.8 µg/kg/min). Baseline IONM recordings were acquired in all patients without any difficulty. The two groups were comparable with respect to the number of additional boluses of fentanyl, patient movements, and recovery characteristics. Conclusion Dexmedetomidine as an adjuvant to propofol in TIVA reduces the requirement of the latter, without affecting the IONM recordings. The addition of dexmedetomidine also ensures stable hemodynamics and decreases the requirement of opioids with similar recovery characteristics.

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.

Postoperative Nausea and Vomiting According to Target-Controlled or Manual Remifentanil Infusion in Gynecological Patients Undergoing Pelviscopic Surgery: A Randomized Controlled Trial

BACKGROUND

We compared the incidence of postoperative nausea and vomiting (PONV) and postoperative outcomes, according to the remifentanil infusion method, during surgery in patients with a high-risk of PONV.

METHODS

Ninety patients undergoing elective gynecological pelviscopic surgery were randomly allocated to either target-controlled infusion (TCI, T) or manual (M) infusion. The primary outcome was the incidence of PONV until postoperative day (POD) 2. The secondary outcomes were perioperative heart rate (HR), blood pressure (BP), numerical rating scale pain scores up to POD2, and postoperative hospital length of stay.

RESULTS

Forty-four patients in the T group and 45 patients in the M group were analyzed. The total dose of remifentanil infusion was significantly higher in the T group (T group: 0.093 (0.078-0.112) μg/kg/min; M group: 0.062 (0.052-0.076) µg/kg/min, p < 0.001). Within POD2, the overall PONV was not significantly different (27 (61.4%) vs. 27 (60.0%), p = 0.895). The HR (82 ± 11.5/min vs. 87 ± 11.1/min, p = 0.046) and mean BP (83 ± 17.2 mmHg vs. 90 ± 16.7 mmHg, p = 0.035) were significantly lower in the T group after tracheal intubation. The other postoperative outcomes were comparable between the two groups.

CONCLUSIONS

Although the total remifentanil infusion dose was higher in the T group than in the M group, the postoperative outcomes were similar. If stable vital signs are desired during tracheal intubation, remifentanil infusion with TCI should be considered.

Houston Methodist Ruptured Abdominal Aortic Aneurysm Guidelines

Ruptured abdominal aortic aneurysm (RAAA) is an acute aortic condition that requires emergent intervention and appropriate continuity of care to optimize patient outcomes. We describe the standardized RAAA protocol at the Houston Methodist Hospital Acute Aortic Treatment Center, developed to navigate critical patient transfer periods safely and efficiently, make crucial decisions about surgical intervention, and clearly communicate these plans with other care team providers. Our workflow is organized into five phases: prehospital, preoperative, intraoperative, postoperative, and post-discharge. We identify the transfer center, anesthesia, operating room nursing staff, surgeons, and intensive care unit as key entities of our acute aortic pathology care team. This systematic protocol for the management of acute aortic emergencies such as RAAA identifies critical decision points, potential complications at each stage, and recommendations for best practice.

Enhanced recovery after bariatric surgery: an Italian consensus statement

Background

Enhanced recovery after bariatric surgery (ERABS) is an approach developed to improve outcomes in obese surgical patients. Unfortunately, it is not evenly implemented in Italy. The Italian Society for the Surgery of Obesity and Metabolic Diseases and the Italian Society of Anesthesia, Analgesia, Resuscitation and Intensive Care joined in drafting an official statement on ERABS.

Methods

To assess the effectiveness and safety of ERABS and to develop evidence-based recommendations with regard to pre-, intra-, and post-operative care for obese patients undergoing ERABS, a 13-member expert task force of surgeons and anesthesiologists from Italian certified IFSO center of excellence in bariatric surgery was established and a review of English-language papers conducted. Oxford 2011 Levels of Evidence and U.S. Preventive Services Task Force Grade Definitions were used to grade the level of evidence and the strength of recommendations, respectively. The supporting evidence and recommendations were reviewed and discussed by the entire group at meetings to achieve a final consensus.

Results

Compared to the conventional approach, ERABS reduces the length of hospital stay and does not heighten the risk of major post-operative complications, re-operations, and hospital re-admissions, nor does it increase the overall surgical costs. A total of 25 recommendations were proposed, covering pre-operative evaluation and care (7 items), intra-operative management (1 item, 11 sub-items), and post-operative care and discharge (6 items).

Conclusions

ERABS is an effective and safe approach. The recommendations allow the proper management of obese patients undergoing ERABS for a better outcome.

Effect of dexamethasone on intraoperative remifentanil dose in total knee arthroplasty surgery under general anaesthesia

Background

The effects of glucocorticoids may include both genomic and rapid nongenomic effects. The potential rapid analgesic effect during surgery has not previously been investigated. We aimed to explore the effect of dexamethasone on intraoperative infusion rate of remifentanil in patients undergoing total knee arthroplasty (TKA) surgery under general anaesthesia.

Methods

In this post hoc subgroup analysis, we included patients randomised in the DEX‐2‐TKA trial, who were operated under total intravenous anaesthesia with remifentanil and propofol. Trial medication, intravenous dexamethasone 24 mg or placebo, was administered immediately after anaesthesia onset. The primary outcome was the median weight‐corrected infusion rate of remifentanil during surgery. Secondary outcomes included median weight‐corrected infusion rate of propofol, median intraoperative bispectral index and time spent in the post‐anaesthesia care unit.

Results

Eighty‐seven patients were included in the analysis of the primary outcome. A significantly higher remifentanil infusion rate was observed in the dexamethasone group compared with the placebo group, p = .02. None of the secondary outcomes resulted in statistically significant differences between groups.

Conclusion

This explorative post hoc analysis of the randomised DEX‐2‐TKA trail showed that patients undergoing TKA surgery under general anaesthesia and who received dexamethasone seemed to have a higher remifentanil infusion rate compared with patients who received placebo. The clinical implications of the potentially increased remifentanil infusion rate need to be validated and explored further.

Clinical trial registration

ClinicalTrials.gov Identifier: NCT05002361 (12 August 2021).

Effects of Preoperative Electroacupuncture on Remifentanil-Induced Post-Infusion Hyperalgesia in Patients Undergoing Thyroidectomy: A Double-Blind Randomized Controlled Trial

Objective

Electroacupuncture (EA) delivered one day before surgery could reduce postoperative pain. Remifentanil-induced post-infusion hyperalgesia (RPH) was occurred after exposure to high-dose remifentanil. This study aimed to investigate the effects of preoperative EA on RPH in patients undergoing thyroidectomy.

Methods

A total of 80 patients who were scheduled to undergo elective thyroidectomy were randomly assigned to two groups: an EA group and a sham EA (SEA) group. EA was delivered at the Zusanli (ST36) and Neiguan (PC6) acupoints 24 h before the surgery. To ensure uniformity across all patients, remifentanil was administered at the same set rate (0.3 μg/kg/min) to all patients. Mechanical pain thresholds were recorded by an electronic von Frey device around the skin incision and on the arm before surgery as well as at 30 min and 6, 24, and 48 h after surgery.

Results

At 30 min and 6 h after surgery, the EA group showed considerably greater mechanical pain thresholds surrounding the surgical site compared with the SEA group. At 30 min and 6 h after surgery, the patients in the SEA group showed a greater incidence of postoperative hyperalgesia surrounding the surgical site than those in the EA group. At 24 and 48 h after surgery, no significant differences were found between the two groups, although the pain intensity of the EA group was less than that of the SEA group. There were also no substantial differences between the two groups in the frequency of postoperative adverse reactions and rescue analgesia needed.

Conclusion

EA administered 24 h before surgery could alleviate RPH in patients undergoing thyroidectomy.

The Effects of Remifentanil and Fentanyl on Emergence Agitation in Pediatric Strabismus Surgery

Emergence agitation (EA) is one of the main concerns in the field of pediatric anesthesia using sevoflurane. We investigated the effects of remifentanil and fentanyl on the incidence of EA in pediatric patients undergoing strabismus surgery. Ninety children were randomly allocated into two groups and received either remifentanil (group R: intraoperatively remifentanil 0.2 μg/kg/min) or fentanyl (group F: fentanyl 2 μg/kg at anesthetic induction) intraoperatively. After surgery, EA incidence was assessed using a four-point agitation scale and Pediatric Anesthesia Emergence Delirium (PAED) scale in the post-anesthesia care unit. Face, leg, activity, cry, and consolability (FLACC) scores for postoperative pain were also assessed. The incidence of EA using the four-point agitation scale (scores ≥ 3) was similar in both groups (remifentanil group, 28.89% vs. fentanyl group, 24.44%). Similar results were obtained using the PAED scale (scores > 12), with an incidence of 33.33% in the remifentanil group and 26.67% in the fentanyl group. Differences in FLACC scores were not found to be statistically significant. A single bolus administration of fentanyl during anesthetic induction and continuous infusion of remifentanil during surgery had similar effects on the EA incidence in these pediatric patients.

Remifentanil Promotes PDIA3 Expression by Activating p38MAPK to Inhibit Intestinal Ischemia/Reperfusion-Induced Oxidative and Endoplasmic Reticulum Stress

Background: Remifentanil protects against intestinal ischemia/reperfusion (I/R) injury; however, its exact mechanism remains to be elucidated. The objective of this study was to investigate the underlying molecular mechanism of remifentanil in intestinal I/R injury in mice.

Methods: We evaluated the intestine-protective effect of remifentanil in adult male mice with 45 min superior mesenteric artery occlusion followed by 4 h reperfusion by determining the following: intestinal Chiu’s scores, diamine oxidase, and intestinal fatty acid binding protein in serum; the apoptotic index, lipid peroxidation product malondialdehyde (MDA), and superoxide dismutase (SOD) activity in the intestinal mucosa; and the intestinal mRNA and protein expressions of Bip, CHOP, caspase-12, and cleaved caspase-3, reflecting endoplasmic reticulum (ER) stress. Furthermore, conditional knockout mice, in which the protein disulfide isomerase A3 (PDIA3) gene was deleted from the intestinal epithelium, and SB203580 (a selective p38MAPK inhibitor) were used to determine the role of PDIA3 and p38MAPK in I/R progression and intestinal protection by remifentanil.

Results: Our data showed that intestinal I/R induced obvious oxidative stress and endoplasmic reticulum stress–related cell apoptosis, as evidenced by an increase in the intestinal mucosal malondialdehyde, a decrease in the intestinal mucosal SOD, and an increase in the apoptotic index and the mRNA and protein expression of Bip, CHOP, caspase-12, and cleaved caspase-3. Remifentanil significantly improved these changes. Moreover, the deletion of intestinal epithelium PDIA3 blocked the protective effects of remifentanil. SB203580 also abolished the intestinal protection of remifentanil and downregulated the mRNA and protein expression of PDIA3.

Conclusion: Remifentanil appears to act via p38MAPK to protect the small intestine from intestinal I/R injury by its PDIA3-mediated antioxidant and anti-ER stress properties.

Annexin A2 traps mu-opioid receptors in recycling endosomes upon remifentanil-induced internalization

•ANXA2 is a novel MOR1-interacting protein regulating MOR1 sub-cellular localization.•ANXA2 retains MOR1 in late recycling endosomes after remifentanil exposure.

Spontaneous breathing for managing analgesia during balanced anesthesia with remifentanil and desflurane: a prospective, single center randomized controlled trial

The main goal of anesthesiology is to achieve the best level of analgesia and a fast recovery of consciousness following anesthesia. The preservation of spontaneous breathing during general anesthesia with anesthetic gases is practiced by many anesthetists. However, very few studies have dealt with these positive properties of volatile anesthetics such as sevoflurane or desflurane. Remifentanil is a very short half-life opiate that combines sufficient intra-operative analgesia with a fast post-operative recovery time. We tested the hypothesis that spontaneous breathing can reduce overdosing with remifentanil during desflurane anesthesia. In this prospective, single center, multiple anesthetist study, 30 patients were randomized into two groups (volume-controlled ventilation mode and spontaneous breathing). The spontaneous breathing group showed a significantly lower post-operative pain level than the volume-controlled ventilation mode group. Furthermore, less remifentanil as well as less piritramide was needed in the spontaneous breathing group compared with volume-controlled ventilation mode. It was possible to achieve spontaneous breathing in all patients with 0.6 minimum alveolar concentration desflurane, in order to control the remifentanil rate and prevent an overdose. All spontaneous breathing patients had low intra- and post-operative pain levels and the need for analgesics was equal to or lower than that in the volume-controlled ventilation mode group. By reducing the intra-operative amount of opiates, both the post-operative pain and the amount of post-operative analgesia required can be reduced. A balanced anesthesia with spontaneous intra-operative breathing is needed to determine the required amount of opiates. This study was approved by the Ethic Committee of the Ruhr-University of Bochum (approval No. 2435) in September, 2004.

A systematic review and meta-analysis of the safety and efficacy of remifentanil and dexmedetomidine for awake fiberoptic endoscope intubation

BACKGROUND

Awake fiberoptic endoscope intubation (AFOI) is the primary strategy for managing anticipated difficult airways. Adequate sedation, most commonly being achieved with remifentanil and dexmedetomidine, is integral to this procedure. This meta-analysis aimed to compare the safety and efficacy of these 2 sedatives.

METHODS

We conducted electronic searches in Embase, Web of Science, PubMed, Google Scholar, Medline, Springer, and Web of Science with no language restrictions. Studies comparing safety and efficacy between the sole use of remifentanil and dexmedetomidine among patients who underwent AFOI were included. Eight randomized controlled trials, comprising 412 patients, met the inclusion criteria. The primary outcomes were first attempt intubation success rate and incidence of hypoxia. The secondary outcomes were the Ramsay Sedation Scale score at intubation, memory recall of endoscopy, and unstable hemodynamic parameters during intubation.

RESULTS

Dexmedetomidine significantly reduced the incidence of hypoxemia during AFOI (risk ratio: 2.47; 95% confidence [CI]: 1.32-4.64]) compared with remifentanil; however, the first intubation success rates were equivalent (risk ratio: 1.12; 95% CI: 0.87-1.46]. No significant differences between the 2 sedatives were found for the Ramsay Sedation Scale score at intubation (mean difference: -0.14; 95% CI: -0.66-0.38) or unstable hemodynamic parameters during intubation (risk ratio: 0.83; 95% CI: 0.59-1.17). Dexmedetomidine reduced memory recall of endoscopy (risk ratio: 1.39; 95% CI: 1.13-1.72).

CONCLUSIONS

While both remifentanil and dexmedetomidine are effective for AFOI and well-tolerated, dexmedetomidine may be more effective in reducing the incidence of hypoxemia and memory recall of endoscopy.

PROSPERP REGISTRATION NUMBER

CRD42020169612.

Effects of an Intraoperative Intravenous Bolus Dose of Dexmedetomidine on Remifentanil-Induced Postinfusion Hyperalgesia in Patients Undergoing Thyroidectomy: A Double-Blind Randomized Controlled Trial

BACKGROUND

Consecutive exposure to high-dose remifentanil during anesthesia may induce remifentanil-induced postinfusion hyperalgesia (RPH). Dexmedetomidine, a highly selective α2-adrenergic receptor agonist, may have synergistic effects with opioids and aid in perioperative pain management. In this study, we hypothesized that an intraoperative bolus dose of intravenous dexmedetomidine could alleviate RPH in patients undergoing thyroidectomy under general anesthesia.

METHODS

Ninety patients undergoing thyroidectomy were randomly assigned to 1 of 3 groups: placebo, normal saline (group P); low-dose dexmedetomidine 0.2 μg·kg-1 (group LD); or high-dose dexmedetomidine 0.5 μg·kg-1 (group HD). Remifentanil was infused at a rate of 0.30 μg·kg-1·minute-1. Mechanical pain thresholds were measured using an Electronic von Frey device preoperatively and at 30 minutes, 6 hours, 24 hours, and 48 hours after surgery and were analyzed with 2-way repeated-measures analysis of variance (ANOVA) followed by Bonferroni post hoc comparison. We also recorded postoperative pain scores, the incidence of receiving rescue analgesics, and side effects up to 48 hours after surgery.

RESULTS

The mechanical pain thresholds around the skin incision were significantly higher in group LD compared to group P 30 minutes and 6 hours after surgery (mean ± standard deviation: [65.0 ± 25.2] vs [49.6 ± 24.4] g, mean difference [95% confidence interval]: 15.4 [0.3-30.5] g, P = .045 at 30 minutes; [65.9 ± 24.5] vs [49.3 ± 26.1] g, 16.6 [1.1-32.1] g, P = .032 at 6 hours). The pain thresholds around the skin incision were significantly higher in group HD compared to group P 30 minutes and 6 hours after surgery ([67.8 ± 21.7] vs [49.6 ± 24.4] g, 18.2 [3.1-33.3] g, P = .013 at 30 minutes; [68.3 ± 22.5] vs [49.3 ± 26.1] g, 19.0 [3.5-34.5] g, P = .011 at 6 hours). The incidence of hyperalgesia around the skin incision was lower in group HD than in group P 30 minutes and 6 hours after surgery (4 [13%] vs 14 [48%], P = .012 at 30 minutes, 4 [13%] vs 12 [41%], P = .045 at 6 hours), although no significant difference was observed between group LD and group P. Postoperative pain scores, the incidence of rescue analgesic demand, and postoperative side effects were not significantly different between the groups.

CONCLUSIONS

An intraoperative intravenous bolus dose of dexmedetomidine 0.5 μg·kg-1 alleviates remifentanil-induced hyperalgesia in patients undergoing thyroidectomy without a significant difference in side effects.

Which idea is better with regard to immune response? Opioid anesthesia or opioid free anesthesia

The stress of surgery is characterized by an inflammatory response with immune suppression resulting from many factors, including the type of surgery and the kind of anesthesia, linked with the drugs that are used and the underlying disease of the patient. The trauma of surgery triggers a cascade of reactions involving the immune response and nociception. As strong analgesics, opioids provide the analgesic component of general anesthesia with bi-directional effect on the immune system. Opioids influence almost all aspects of the immune response in regards to leukocytes, macrophages, mast cells, lymphocytes, and NK cells. The suppressive effect of opioids on the immune system is limiting their use, especially in patients with impaired immune response, so the possibility of using multimodal anesthesia without opioids, known as opioid-free anesthesia (OFA), is gaining more and more sympathizers. The idea of OFA is to eliminate opioid analgesia in the treatment of acute pain and to replace it with drugs from other groups that are assumed to have a comparable analgesic effect without affecting the immune system. Here, we present a review on the impact of anesthesia, with and without the use of opioids, on the immune response to surgical stress.

Remifentanil repairs cartilage damage and reduces the degradation of cartilage matrix in post-traumatic osteoarthritis, and inhibits IL-1β-induced apoptosis of articular chondrocytes via inhibition of PI3K/AKT/NF-κB phosphorylation

Background

Remifentanil (RFT) is an opioid analgesic with a unique pharmacokinetic profile, and plays an important role in the intra- and post-operative periods. Post-traumatic osteoarthritis (PTO) is a particular type of osteoarthritis (OA) that occurs secondary to a traumatic injury. In the present study, we investigated the effects of RFT both in vivo and in vitro.

Methods

In vivo, 50 Sprague Dawley (SD) rats (7 weeks old) were randomly divided into five groups. Four groups of rats received RFT (0.2, 0.5, and 1 µg) or vehicle (PTO group), while the remaining group served as the control. A PTO model in rats was established using the Hulth method. The cartilage damage, articular cartilage formation, and the degradation of cartilage matrix were evaluated. The effects of RFT on cell proliferation, apoptosis, and nuclear factor (NF)-κB phosphorylation were also examined.

Results

The results indicated that RFT improved cartilage damage, enhanced articular cartilage formation, and inhibited the degradation of cartilage matrix in PTO model rats. Compared with the control group, the protein levels of Osterix (OSX), Collagen type I alpha 1 (COL1A1), and osteocalcin (OC) were down-regulated in PTO model rats. RFT also inhibited the interleukin-1β (IL-1β)-induced apoptosis of chondrocytes in vitro. Furthermore, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/NF-κB pathway was inhibited both in vitro and in vitro.

Conclusions

RFT has significant potential as a therapeutic intervention to ameliorate PTO and provides a foundation for further clinical studies.

Attenuation of the increase in intraocular pressure with dexmedetomidine: Systematic review with meta-analysis and trial sequential analysis

STUDY OBJECTIVE

Whether dexmedetomidine effectively attenuates the increase in intraocular pressure (IOP) remains inconclusive. We aim to evaluate the effects of dexmedetomidine on IOP in adult patients undergoing surgery which requires general anesthesia and endotracheal intubation.

DESIGN

Systematic review and meta-analysis.

INTERVENTIONS

Intravenous administration of dexmedetomidine during surgery.

MEASUREMENTS

Intraocular pressure.

METHODS

We searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, Google Scholar, Wanfang Data, and China National Knowledge Infrastructure from the inception through April 14, 2020. Randomized control trials which involved adult patients undergoing surgery that required general anesthesia and endotracheal intubation, which compared intravenous administration of dexmedetomidine with placebo regarding the IOP levels, which also provided sufficient information for meta-analysis were considered eligible.

MAIN RESULTS

Twenty-nine randomized control trials were included. The IOP levels are significantly lower in patients receiving dexmedetomidine after the administration of dexmedetomidine [mean difference (MD), -2.04 mmHg; 95% confidence interval (CI), -2.40 mmHg to -1.67 mmHg], after the injection of succinylcholine (MD, -3.84 mmHg; 95% CI, -4.80 mmHg to -2.88 mmHg), after endotracheal intubation (MD, -3.64 mmHg; 95% CI, -4.46 mmHg to -2.82 mmHg), after pneumoperitoneum (MD, -3.12 mmHg; 95% CI, -3.93 mmHg to -2.30 mmHg), and after the patients being placed in a steep Trendelenburg position (MD, -4.12 mmHg; 95% CI, -5.39 mmHg to -2.85 mmHg). Trial sequential analyses for these outcomes are conclusive.

CONCLUSIONS

Dexmedetomidine effectively attenuates the increase in IOP levels, and should be considered especially for at-risk patients.

Preemptive local anesthetic infiltration reduces opioid requirements without attenuation of the intraoperative electrical stapedial reflex threshold in pediatric cochlear implant surgery

Background and Aims:

Total intravenous anesthesia using remifentanil provides good surgical condition without affecting the intraoperative electrical stapedial reflex threshold (ESRT). However, remifentanil results in hyperalgesia and increases postoperative opioid requirements. Local anesthetic infiltration is alternative methods to opioid for providing analgesia. However, otologists avoids its use as it can abolish the ESRT. We investigated the effect of the preemptive local anesthetic infiltration on intraoperative ESRT and opioid requirements in pediatric cochlear implant surgery performed under TIVA.

Material and Methods:

Prospective, randomized, double-blinded, controlled study including 70 child undergoing cochlear implant under TIVA were randomly assigned to a local anesthesia (LA group, n = 35) or control (CT group, N = 35). The primary outcome was the total tramadol consumption during the first 24 h postoperative, and the secondary outcomes were time to first analgesia request, postoperative pain scores, the ESRT and, propofol and remifentanil requirements. The incidence of postoperative vomiting was recorder as well.

Results:

The total tramadol consumption during the first 24 h after surgery was significantly less in the LA group than in CT group (8.25 [4.3] vs. 16.5 [6.57] mg, P < 0.01). The time to first analgesic request was significantly prolonged in the LA group as compared with the CT group [8 [2–12] vs. 3 [0–8] h, P < 0.01). The postoperative Faces, Legs, Activity, Cry Consolability pain scores were significantly lower in the LA group at 15 min, 30 min, 2, 4 and 6 h postoperative. Mean remifentanil infusion rate [mean (standard deviation)] was significantly higher in in the CT group than in the LA group [0.7 (0.3) vs. 0.5 (0.2) μg/kg/min; P = 0.001).The ESRT response, propofol requirements, and the incidence of postoperative vomiting had no significant differences between both groups.

Conclusion:

Preemptive local anesthetic infiltration reduced opioid requirements without attenuation of the ESRT in pediatric cochlear implant surgery performed under TIVA.

Remifentanil for Carboprost-Induced Adverse Reactions During Cesarean Delivery Under Combined Spinal-Epidural Anesthesia

Purpose

Carboprost may induce adverse reactions when used to treat postpartum hemorrhage. We aimed to explore the effects of intravenous infusion of low-dose remifentanil to prevent such reactions.

Methods

We enrolled parturient patients scheduled for elective cesarean section. Anesthesiologist administered combined spinal epidurals at the L3/4 interspace, with 0.5% hyperbaric bupivacaine subarachnoid space injections (1.5–2.5 ml). We randomly divided parturient patients, administered carboprost during surgery, into the remifentanil group (group R) and the control group (group C). Patients in group R received an intravenous target-controlled infusion of remifentanil (target effect-site concentration, 1.5 ng/ml) simultaneously with a carboprost tromethamine injection (250 µg). Patients in group C received a normal saline infusion with carboprost. We recorded and analyzed the incidence of carboprost-related adverse reactions (vomiting, nausea, chest congestion, flushing, hypertension, tachycardia, cough, and shivering), and assessed patient comfort using a numerical rating scale ([NRS], on which 0 was very uncomfortable and 10 was very comfortable).

Results

After applying inclusion and exclusion criteria, we conducted statistical analysis of the data from 70 women. The incidence of vomiting was significantly lower in group R than in group C (14.3 vs. 51.4%, p < 0.01); and the incidence of nausea, chest congestion, facial flushing, and hypertension were significantly lower in group R than in group C (all p < 0.01). Furthermore, the patients’ comfort scores were significantly higher in group R than in group C (8.0 ± 1.8 vs. 3.6 ± 2.1, p < 0.01).

Conclusion

Our results demonstrate that an intravenous low-dose remifentanil infusion can effectively prevent carboprost-related adverse reactions during cesarean delivery under combined spinal and epidural anesthesia.

Clinical Trial Registration

We pre-registered this study at http://www.chictr.org.cn/showproj.aspx?proj=27707 (ChiCTR1800016292).

Remifentanil preconditioning protects against hypoxia-induced senescence and necroptosis in human cardiac myocytes in vitro

Remifentanil and other opioids are suggested to be protective against ischemia-reperfusion injury in animal models and coronary artery bypass surgery patients, however the molecular basis of such protection is far from being understood. In the present study, we have used a model of human cardiomyocytes treated with the hypoxia-mimetic agent cobalt chloride to investigate remifentanil preconditioning-based adaptive responses and underlying mechanisms. Hypoxic conditions promoted oxidative and nitrosative stress, p21-mediated cellular senescence and the activation of necroptotic pathway that was accompanied by a 2.2-, 9.6- and 8.2-fold increase in phosphorylation status of mixed lineage kinase domain-like pseudokinase (MLKL) and release of pro-inflammatory cytokine IL-8 and cardiac troponin I, a marker of myocardial damage, respectively. Remifentanil preconditioning was able to lower hypoxia-mediated protein carbonylation and limit MLKL-based signaling and pro-inflammatory response to almost normoxic control levels, and decrease hypoxia-induced pro-senescent activity of about 21% compared to control hypoxic conditions. In summary, we have shown for the first time that remifentanil can protect human cardiomyocytes against hypoxia-induced cellular senescence and necroptosis that may have importance with respect to the use of remifentanil to diminish myocardial ischemia and reperfusion injury in patients undergoing cardiac surgery.

Remifentanil attenuates cardiac dysfunction, lipid peroxidation and immune disorder in rats with isoproterenol-induced myocardial injury via JNK/NF-KB p65 inhibition

Background

Myocardial injury caused by myocardial ischemia (MI) is still a severe condition that can result in apoptosis, oxidative stress, and inflammation. Remifentanil is a selective, ultra-short-acting, µ-opioid receptor agonist opioid. It can improve sinusoidal heart rate patterns in the fetus, for bupivacaine-induced cardiotoxicity, and with lipopolysaccharide (LPS)-induced cardiomyocytes injuries. This study aimed to explore the cardioprotective effects of remifentanil in MI model rats.

Methods

Sprague Dawley (SD) rats were split into five groups at random, including a control group, Isop group, low-dose remifentanil treatment group (10 µg/kg), medium-dose remifentanil treatment group (20 µg/kg), and a high-dose remifentanil treatment group (40 µg/kg). The MI model was achieved by subcutaneously injecting rats with isoproterenol (85 mg/kg) for two consecutive days. With the expression of apoptotic molecules, myocardial systolic function index, inflammation, antioxidant enzymes, and the myocardial enzyme taken into account, the data was analyzed.

Results

After treatment with remifentanil, the left ventricular wall thickness (LVWT), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), fraction shortening (FS), and heart rate (HR) were significantly increased in comparison with the Isop group. Creatine kinase-MB (CK-MB), Mb, and cTnl expressions were decreased. Meanwhile, the levels of cleaved caspase-3 and caspase-9 were decreased. Remarkably, the levels of reactive oxidative species (ROS), malondialdehyde (MDA), and lactate dehydrogenase (LDH) were observed to be repressed, while the levels of superoxide dismutase (SOD) was significantly increased. More importantly, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and interferon (IFN)-γ were decreased.

Conclusions

Remifentanil has significant potential as a therapeutic intervention strategy for ameliorating myocardial injury after MI and these findings provide the rationale for further clinical studies.

Effects of remifentanil preconditioning on factors related to uterine contraction in WISH cells

Background

Preterm labor and miscarriage may occur in stressful situations, such as a surgical operation or infection during pregnancy. Pharyngeal and buccal abscess and facial bone fractures are inevitable dental surgeries in pregnant patients. Remifentanil is an opioid analgesic that is commonly used for general anesthesia and sedation. Nonetheless, no study has investigated the effects of remifentanil on amniotic epithelial cells. This study evaluated the effects of remifentanil on the factors related to uterine contraction and its mechanism of action on amniotic epithelial cells.

Methods

Amniotic epithelial cells were preconditioned at various concentrations of remifentanil for 1 h, followed by 24-h lipopolysaccharide (LPS) exposure. MTT assays were performed to assess the cell viability in each group. The effects of remifentanil on factors related to uterine contractions in amniotic epithelial cells were assessed using a nitric oxide (NO) assay, western blot examinations of the expression of nuclear factor-kappa B (NF-κB), cyclooxygenase 2 (COX2), and prostaglandin E2 (PGE₂), and RT-PCR examinations of the expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-alpha (TNF-α).

Results

Remifentanil did not affect viability and nitric oxide production of amniotic epithelial cells. Western blot analysis revealed that remifentanil preconditioning resulted in decreased expressions of NF-κB and PGE₂ in the cells in LPS-induced inflammation, and a tendency of decreased COX2 expression. The results were statistically significant only at high concentration. RT-PCR revealed reduced expressions of IL-1β and TNF-α.

Conclusions

Preconditioning with remifentanil does not affect the viability of amniotic epithelial cells but reduces the expression of factors related to uterine contractions in situations where cell inflammation is induced by LPS, which is an important inducer of preterm labor. These findings provide evidence that remifentanil may inhibit preterm labor in clinical settings.

Low- versus high-dose intraoperative opioids: A systematic review with meta-analyses and trial sequential analyses

BACKGROUND

Opioid-induced hyperalgesia is a state of nociceptive sensitisation secondary to opioid administration. The objective of this meta-analysis was to test the hypothesis that high-dose intraoperative opioids contribute to increased post-operative pain and hyperalgesia when compared with a low-dose regimen in patients under general anaesthesia.

METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines and rated the certainty of evidence with the Grading of Recommendations, Assessment, Development and Evaluation system. Only trials investigating pain outcomes and comparing two different dosages of the same intraoperative opioid in patients under general anaesthesia were included. The primary outcome was pain score (analogue scale, 0-10) at 24 post-operative hours. Secondary outcomes included pain score and cumulative intravenous morphine equivalents (mg) consumed at 2 post-operative hours, together with mechanical pain threshold (g·mm^-2 ).

RESULTS

Twenty-seven randomised controlled trials, including 1630 patients, were identified. Pain score at rest at 24 post-operative hours was increased in the high-dose group (mean difference [95% CI]: -0.2 [-0.4, -0.1]; trial sequential analysis-adjusted CI: -0.4, -0.02; low certainty of evidence). Similarly, at 2 post-operative hours, both pain score (mean difference [95% CI]: -0.4 [-0.6, -0.2]; low certainty of evidence) and cumulative intravenous morphine equivalents consumed (mean difference [95% CI]: -1.6 mg [-2.6, -0.7]; low certainty of evidence) were significantly higher in the high-dose group. Finally, the threshold for mechanical pain was significantly lower in the high-dose group (mean difference to pressure [95% CI]: 3.8 g·mm^-2 [1.8, 5.8]; low certainty of evidence).

CONCLUSIONS

There is low certainty of evidence that high-dose intraoperative opioid administration increases pain scores in the post-operative period, when compared with a low-dose regimen.

Anti-inflammatory effect of remifentanil in lipopolysaccharide-stimulated amniotic epithelial cells

Background

Sometimes general anesthesia is required for dental surgery in pregnant women. Facial bone fractures or neck abscess should be treated immediately. Dental surgery, however, creates a stressful situation that can cause inflammation. Inflammatory responses are a well-known major cause of preterm labor and preterm birth. Here we demonstrate the effects of remifentanil on the factors related to preterm labor and its mechanism of action on amniotic-derived epithelial cells (WISH cells).

Methods

WISH cells were exposed to lipopolysaccharide (LPS) for 24 h and co-treated with various concentrations of remifentanil. MTT assays were performed to measure cell viability. To explain the effects of remifentanil on the factors related to inflammation in WISH cells, activation of nuclear factor kappa B (NF-κB) and p38 and the expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, cyclooxygenase (COX)2, and prostaglandin E (PGE)₂ were quantified using western blotting and RT-PCR, respectively.

Results

Remifentanil did not affect WISH cell viability. In western blot analysis, co-treatment with remifentanil resulted in decreased phosphorylation of NF-κB, and expression of COX2 and PGE₂ in LPS-induced inflammation, but the results were statistically significant only at low concentrations. Reduction of IL-1β and TNF-α expression was also observed with RT-PCR.

Conclusion

Co-treatment with remifentanil does not affect the viability of WISH cells, but reduces the expression of the factors related to inflammation, which can induce uterine contraction and preterm labor. These findings provide evidence that remifentanil may inhibit uterine contraction and preterm labor in clinical settings.

The efficacy of esmolol, remifentanil and nitroglycerin in controlled hypotension for functional endoscopic sinus surgery

Introduction

Controlled hypotension is a reversible procedure in which the patient’s baseline mean arterial blood pressure is reduced by 30% and sustained at 60–70 mmHg during the procedure. It decreases blood loss and provides clear surgical field during the procedures.

Objectives

The purpose of this study was to compare the efficacy of controlled hypotension agents esmolol, remifentanil, and nitroglycerin in functional endoscopic sinus surgery, in terms of hemodynamic changes and impact on the surgical efficiency.

Methods

The research was carried out as a cohort study. Patients who underwent functional endoscopic sinus surgery were randomized into 3 groups. Controlled hypotension was achieved with remifentanil (Group R), esmolol (Group E) and nitroglycerin (Group N). The efficacy of the drugs was tested by comparing the length of time with the targeted mean arterial pressure, the amount of anesthetics used, surgical field bleeding score and surgeon’s satisfaction.

Results

Between May to December 2015, 60 patients were included and randomized equally into 3 different study groups. The median of the length of time with the targeted mean arterial pressure was shorter in the Group R when compared with Group E (p = 0.01) and Group N (p = 0.14). The amount of volatile anesthetics used was 25.0 mL (15–51), 43.0 mL (21–105) and 40.0 mL (26–97) in Groups R, E and N, respectively (p < 0.001). While there was more bleeding with nitroglycerin, surgical field bleeding scores were lower in Group R when compared with esmolol (p = 0.001) and nitroglycerin (p < 0.001). The analysis of surgeon’s satisfaction scores concluded that surgeons were more satisfied with the group R (100%), when compared with group E (60%) and group N (30%) (p < 0.001).

Conclusion

Less volatile agent, short time to achieve controlled hypotension, stable blood pressure, lower surgical field bleeding scores and larger length of time with the targeted mean arterial pressure were found as the advantages of Remifentanil. Less costly, efficiency of achieving the targeted median arterial pressure and less postoperative complications were the advantages of nitroglycerin. In functional endoscopic sinus surgery procedures, appropriate controlled hypotensive agents should be selected according to the patients’ characteristics and advantages/disadvantages of the drugs.

From Clinical Trial Efficacy to Real-Life Effectiveness: Why Conventional Metrics do not Work

Background

Randomised, double-blind, clinical trial methodology minimises bias in the measurement of treatment efficacy. However, most phase III trials in non-orphan diseases do not include individuals from the population to whom efficacy findings will be applied in the real world. Thus, a translation process must be used to infer effectiveness for these populations. Current conventional translation processes are not formalised and do not have a clear theoretical or practical base. There is a growing need for accurate translation, both for public health considerations and for supporting the shift towards personalised medicine.

Objective

Our objective was to assess the results of translation of efficacy data to population efficacy from two simulated clinical trials for two drugs in three populations, using conventional methods.

Methods

We simulated three populations, two drugs with different efficacies and two trials with different sampling protocols.

Results

With few exceptions, current translation methods do not result in accurate population effectiveness predictions. The reason for this failure is the non-linearity of the translation method. One of the consequences of this inaccuracy is that pharmacoeconomic and postmarketing surveillance studies based on direct use of clinical trial efficacy metrics are flawed.

Conclusion

There is a clear need to develop and validate functional and relevant translation approaches for the translation of clinical trial efficacy to the real-world setting.

Electronic supplementary material

The online version of this article (10.1007/s40801-019-0159-z) contains supplementary material, which is available to authorized users.

Hemodynamic parameters and reproductive outcome after intracytoplasmic sperm injection and fresh embryo transfer in patients undergoing oocyte retrieval with general anesthesia using fentanyl, remifentanil or alfentanil - A randomized clinical trial

OBJECTIVE

Anesthesia for assisted reproductive technology is very important to provide less stressful and painful environment for patients, with minimal side effects on oocytes. In the present study, we aimed to evaluate hemodynamic parameters, recovery time and intracytoplasmic sperm injection (ICSI) outcome among patients underwent anesthesia with fentanyl, remifentanil or alfentanil.

MATERIAL AND METHODS

This randomized double-blinded clinical trial was conducted in patients undergoing anesthesia for transvaginal ultrasound guided oocyte retrieval (TUGOR). Patients were randomly allocated to alfentanil (A; 15 μg/kg), fentanyl (F; 1.5 μg/kg) or remifentanil (R; 1.5 μg/kg) groups.

RESULTS

Three hundred forty patients were assessed for eligibility and randomized for transvaginal oocyte retrieval following general anesthesia and 105 were lost to follow up. No statistically significant differences were noted among groups regarding basic characteristics. Although, time to respond to verbal command was significantly different among groups (A: 1.99 ± 1.64, F: 2.56 ± 1.72, R: 1.78 ± 1.34, P = 0.014). There were no significant differences among groups with respect to the first and second postoperative pain intensity, patient satisfaction, pre-induction and post-induction systolic and diastolic blood pressure (BP). Terminal systolic (A: 101.61 ± 9.15, F: 105.29 ± 12.61, R: 102 ± 12.91, P = 0.01) and diastolic (A: 59.97 ± 9, F: 65.63 ± 9.13, R: 63.69 ± 11.01, P = 0.003) BP was significantly different among groups. The fertilization rate was significantly different among groups (A: 51.6%, F: 54.4%, R: 62.2%, P = 0.018). Implantation rate, biochemical and clinical pregnancy rate was similar among groups.

CONCLUSIONS

The results of present study demonstrated that all three opioids have the same efficiency, in regards to patient satisfaction and pregnancy outcome. However, Anesthesia with alfentanil compared with fentanyl and remifentanil, seems to be inferior for TUGOR due to higher effect on fertilization rate and less hemodynamic stability.

REGISTRATION NUMBER

IRCT201410258677N4.

Remifentanil promotes osteoblastogenesis by upregulating Runx2/osterix expression in preosteoblastic C2C12 cells

Background

The imbalance between osteoblasts and osteoclasts can lead to pathological conditions such as osteoporosis. It has been reported that opioid adversely affect the skeletal system, but it is inconsistent. Remifentanil is currently used as an adjuvant analgesic drug in general anesthesia and sedation. The aim of the present study was to investigate the effect of remifentanil on the osteoblast differentiation and mechanism involved in this effect.

Methods

The C2C12 cells (mouse pluripotent mesenchymal cell line) were used as preosteoblast. Osteoblastic differentiation potency was determined by alkaline phosphatase (ALP) staining. C2C12 cell migration by remifentanil was evaluated using Boyden chamber migration assay. The expression of Runx2 and osterix was evaluated by RT-PCT and western blot analysis to investigate the mechanism involved in remifentanil-mediated osteoblast differentiation.

Results

ALP staining showed that remifentanil increased significantly osteoblast differentiation. In Boyden chamber migration assay, C2C12 cell migration was increased by remifentanil. RT-PCR and western blot analysis showed that the expression of Runx2 and osterix was upregulated by remifentanil.

Conclusions

We demonstrated that remifentanil increased osteoblast differentiation in vitro by upregulation of Runx2 and osterix expression. Therefore, remifentanil has the potential for assisting with bone formation and bone healing.

A comparison of sufentanil vs. remifentanil in fast-track cardiac surgery patients

We retrospectively compared patients receiving remifentanil with patients receiving sufentanil undergoing fast-track cardiac surgery. After 1:1 propensity score matching there were 609 patients in each group. The sufentanil group had a significantly longer mean (SD) ventilation time compared with the remifentanil group; 122 (59) vs. 80 (44) min, p < 0.001 and longer mean (SD) length of stay in the recovery area; 277 (77) vs. 263 (78) min, p = 0.002. The sufentanil group had a lower mean (SD) visual analogue pain score than the remifentanil group; 1.5 (1.2) vs. 2.4 (1.5), p < 0.001 and consumed less mean (SD) piritramide (an opioid analgesic used in our hospital); 2.6 (4.7) vs. 18.9 (7.3) mg, p < 0.001. The results of our study show that although remifentanil was more effective in reducing time to tracheal extubation and length of stay in the recovery area, there was an increased requirement for postoperative analgesia when remifentanil was used.

A comparison of risk of hypotension using standard doses of remifentanil versus dexmedetomidine infusions in adult patients undergoing surgery under general anaesthesia at the Aga Khan University Hospital, Nairobi

Background

Remifentanil and dexmedetomidine are common agents used in general anaesthesia, monitored anaesthesia care and critical care. When combined with inhaled or intravenous anaesthetic agents intra-operatively, they provide analgesia, lower general anaesthetic requirements and provide sedation and analgesia in the peri-operative period if indicated. Pharmacodynamically, they cause hypotension and bradycardia which are reversible if well managed. Past studies of these drugs have shown a significant proportion of patients with hypotension when compared with similar agents or in isolation. This study compares these two drugs on the effect of hypotension when used as adjuncts to general anaesthesia at low dose standard rate of infusions.

Objective

To compare the proportion of hypotension episodes in a group of adult patients receiving dexmedetomidine infusion at 0.4mcg/kg/hr versus a group receiving remifentanil infusion at 0.2mcg/kg/min, severity of hypotension and physician interventions in each group.

Methods

One hundred and four patients scheduled for elective surgery under general anaesthesia were randomized into two groups: Control group; received remifentanil infusion at 0.2mcg/kg/min

Intervention group; received dexmedetomidine at 0.4mcg/kg/hr.

General anaesthesia was standardized in both groups. The patients were blinded to the study. Baseline blood pressures of all patients were determined prior to induction. The patient's demographic characteristics were recorded. The number of patients who developed hypotension, the frequency of hypotension and the physician interventions were recorded and analysed.

Results

The age and gender characteristics were different between the two groups (p values <0.023 and 0.05 respectively) however they did not affect the proportion of patients with hypotension. The weight, baseline pressures and ASA status of the patients within the groups were similar. The operative procedures varied within the groups. General surgery did not influence the outcome of hypotension in both arms. The duration of surgery in remifentanil group exceeded that of Dexmedetomidine p value<0.0005 however the time to the first episode of hypotension was similar between the groups. The episodes of hypotension were fewer in the dexmedetomidine arm and the proportion of patients with hypotension were higher in the remifentanil arm, p value<0.001, R.R 0. = 0.5938, 95% C.I= 0.329–0.819 The physician interventions administered were similar between the two groups except the use of ephedrine between the groups.

Conclusion

Among this population, at standard infusion rates, the proportion of patients that risk hypotension was greater in those undergoing elective surgery receiving remifentanil at 0.2mcg/kg/min than in dexmedetomidine at 0.4mcg/kg/hr under isoflurane based anaesthesia.

Effect of remifentanil on the recovery profile after head and neck surgeries: A prospective study

Background and Aims:

Development of opioid tolerance in the perioperative period due to remifentanil remains controversial. We evaluated occurrence of opioid tolerance and other adverse effects due to remifentanil in patients undergoing head and neck surgery.

Material and Methods:

We recruited adult participants with ASA status I to III who received general anesthesia for approximately 2 h for elective head and neck procedures. Remifentanil infusion was used in one group and intermittent boluses of morphine or fentanyl were administered in another group. Postoperative pain was treated with intermittent boluses of morphine and fentanyl in post-anaesthesia care unit (PACU) to achieve a numerical rating scale score of 3. Opioid requirement was assessed as an indicator of opioid tolerance. Patients were also evaluated for time to discharge from PACU.

Results:

We studied 222 adults aged between 21 and 80 years. One hundred and eleven patients received a combination of remifentanil infusion and morphine boluses, and another 111 patients received only fentanyl and/or morphine boluses intraoperatively. Fifty-one patients in the remifentanil group and 25 in the fentanyl/morphine group required opioids in the PACU. Opioid requirement were significantly more (mean ± SD, 44.98 ± 59.7 Vs 20.23 ± 46.66 mcg.kg⁻¹; P = 0.001) and required longer time to discharge from PACU in the remifentanil group compared to the fentanyl/morphine group (Mean ± SD, 88.6 ± 39.5 min Vs 73.1 ± 38.4 min; P < 0.001). No difference in the incidence of adverse effects in two groups was noted.

Conclusion:

At clinically relevant doses, intraoperative remifentanil infusion appears to increase opioid consumption in the immediate postoperative period. This can result in delayed discharge from PACU for patients undergoing elective head and neck procedures.

Comparison of Metoprolol and Tramadol with Remifentanil in Endoscopic Sinus Surgery: A Randomised Controlled Trial

Objective

Controlled hypotension is commonly induced during functional endoscopic sinus surgery to limit mucosal bleeding. This may be detrimental to elderly patients and patients with arterial stenosis. The aim of this pilot study was to determine if a normotensive anaesthetic technique with sufficient analgesia and without profound vasodilation may reduce intraoperative bleeding and incidence of adverse haemodynamic effects associated with vasodilation and variable rate continuous infusions.

Methods

In this double-blind randomised controlled trial in a tertiary care centre, a total of 88 patients were randomised to receive intravenously either 0.1 mg kg^-1 metoprolol and 1 mg kg^-1 tramadol following anaesthesia induction (MT group) or a bolus dose of 0.5 μg kg^-1 remifentanil following anaesthesia induction, followed by 0.25-0.5 μg kg^-1 min^-1 remifentanil infusion (R group). The primary outcome was quality of surgical field and incidence of adverse haemodynamic effects. The secondary outcomes were time to achieve intraoperative bleeding score <3, bleeding rate and changes in cerebral regional oximetry.

Results

A total of 105 patients were recruited, in which 88 were randomised. The median intraoperative bleeding score was similar (1, interquartile range: 1-1, p=0.69). The mean bleeding rate was lower in the MT group, although the difference was not significant (p=0.052, 95% CI 0 to 8.8). Hypotension, bradycardia and cerebral desaturation in the MT group were not observed compared to hypotension in 3 (7%), bradycardia in 18 (41%) and cerebral desaturation in 2 (5%) patients in the R group (p=0.241, p<0.001, p=0.474, respectively).

Conclusion

Providing sufficient analgesia and eliminating stress response can provide stable heart rate and good surgical field with no need for additional hypotension. This normotensive technique may be useful in patients with stenotic arteries or ischaemic organ diseases.

General Anesthesia With Dexmedetomidine and Remifentanil in a Neonate During Oracotomy and Resection of a Congenital Cystic Adenomatoid Malformation

Based on animal data, concern has been expressed regarding the potential deleterious neurocognitive effects of general anesthesia during infancy and early life. Although there are no definitive data to prove this effect, the neonatal period has been suggested to be the most vulnerable period. While various inhaled and intravenous anesthetic agents have been implicated, dexmedetomidine and the opioids may be devoid of such effects. However, there are limited data regarding the combination of these agents during neonatal surgery and anesthesia. We present the use of these agents in combination with epidural anesthesia for postoperative analgesia in a 1-day-old neonate during thoracotomy and excision of a congental cystic adenomatoid malformation. Previous reports of the use of this unique combination of agents are reviewed and their role in this scenario discussed.

Effects of age on effect-site concentration of remifentanil for suppressing anesthetic emergence cough in male patients undergoing laparoscopic cholecystectomy

Background

Remifentanil infusion during emergence lowers cough. Effect-site concentration (Ce) of remifentanil using target-controlled infusion (TCI) has been evaluated in previous studies. Recent studies revealed the existence of sex-related differences in remifentanil Ce in young and elderly patients. Thus, there was the need to re-evaluate the effect of age in single sex. We investigated the remifentanil Ce for suppressing emergence cough in young and elderly male patients and evaluated the age-related differences.

Patients and methods

In total, 25 young (ages between 20 and 50 years) and 24 elderly (ages between 65 and 75 years) male patients undergoing laparoscopic cholecystectomy were enrolled. Anesthesia was implemented with remifentanil using TCI and sevoflurane. The remifentanil Ce for suppressing emergence cough was estimated for each group using Dixon’s up-and-down method and isotonic regression method with a bootstrapping approach.

Results

The remifentanil Ce for suppressing emergence cough in 50% (EC₅₀) and 95% (EC₉₅) of the patients was comparable between the young and elderly patients. Isotonic regression demonstrated that the EC₅₀ (83% confidence interval [CI]) of remifentanil was 2.56 (2.39−2.75) ng/mL in the young patients and 2.15 (1.92−2.5) ng/mL in the elderly patients. The EC₉₅ (95% CI) of remifentanil was 3.33 (2.94−3.46) ng/mL in the young patients and 3.41 (3.18−3.48) ng/mL in the elderly patients. Dixon’s up-and-down method also demonstrated that the EC₅₀ was comparable between the two groups (2.69±0.32 ng/mL vs 2.39±0.38 ng/mL, P=0.132).

Conclusion

The remifentanil Ce for suppressing emergence cough following extubation during general anesthesia was comparable between young and elderly male patients. It indicates that age-related differences in remifentanil requirement for suppressing emergence cough did not exist in male sex.