A comparative study of the effect of caudal dexmedetomidine versus morphine added to bupivacaine in pediatric infra-umbilical surgery

A Randomized Controlled Trial of Intrathecal versus Caudal Morphine-Bupivacaine on Postoperative Analgesia and Cortisol Levels in Pediatric Patients

BACKGROUND

Morphine is commonly used in pediatric caudal blocks. We compared the analgesic efficacy and effect on cortisol levels of intrathecal morphine and bupivacaine with caudal morphine and bupivacaine in children undergoing lower abdominal surgeries.

METHODS

Forty children undergoing lower abdominal surgeries were randomized to receive 4 μg/kg of intrathecal morphine and 0.5% hyperbaric bupivacaine (n = 20), or caudal morphine 40 μg/kg and 0.25% bupivacaine (n = 20). Postoperative analgesia was provided with intravenous (IV) paracetamol (PCM). The primary outcome was time to reach Face, Legs, Activity, Cry, and Consolability (FLACC) score ≥4 postoperatively. Secondary outcomes were perioperative serum cortisol levels, analgesic requirement, and parent satisfaction.

RESULTS

Since seventy 5% of patients receiving intrathecal morphine and bupivacaine did not reach a FLACC score ≥4 within 24 hours, the primary outcome was presented as the Kaplan-Meier curve. The probability of FLACC score <4 was significantly higher with intrathecal morphine and bupivacaine than with caudal morphine and bupivacaine (P < .001). The unadjusted and adjusted (for gender) hazard ratio (95% confidence interval [CI]) of occurrence of pain (FLACC score ≥4) was 0.07 (0.03-0.15, P < .001) and 0.06 (0.03-0.14, P < .001), respectively. The difference in means (95% CI) of cortisol levels between caudal morphine (with bupivacaine) and intrathecal morphine (with bupivacaine) groups were after intubation -0.667 (-4.99 to 3.65, P = .76), at 2 hours intraoperatively 7.88 (3.55-12.2, P < .001), 6 hours postoperatively 16.8 (12.5-21.1, P < .001), and 24 hours postoperatively 15.4 (11.1-19.7, P < .001) μg/dL. Intraoperatively, rescue fentanyl was required by 60% of patients on caudal morphine and bupivacaine against 20% of patients receiving intrathecal morphine and bupivacaine (absolute risk-reduction [95% CI] of 40% [12%-68%]; P = .010). Postoperative rescue fentanyl was required in 45% of patients on caudal morphine and bupivacaine and 5% of patients on intrathecal morphine and bupivacaine. All (100%) patients on caudal morphine and bupivacaine required postoperative PCM against 6 (30%) patients on intrathecal morphine and bupivacaine (absolute risk-reduction [95% CI] of 70% [50%-90%]; P < .001).The median (interquartile range [IQR]) parent satisfaction score for patients on caudal morphine (with bupivacaine) and intrathecal morphine (with bupivacaine) was 0(0-0) and 2(2-2) at 12 hours postoperatively (P < .001) and 0(0-1) and 2(1.5-2) at 24 hours postoperatively (P < .001). One patient in each group developed nausea and vomiting, and 1 patient in the intrathecal group developed pruritus. There was no incidence of respiratory depression.

CONCLUSIONS

Intrathecal morphine and bupivacaine results in longer duration of analgesia, lower analgesic consumption, prevents surgical-stress-related elevation of serum cortisol, and improves parent satisfaction compared to caudal morphine with bupivacaine in children undergoing lower abdominal surgeries.

Analgesic Efficacy of Adjuvant Medications in the Pediatric Caudal Block for Infraumbilical Surgery: A Network Meta-Analysis of Randomized Controlled Trials

Various adjuvants are added to local anesthetics in caudal block to improve analgesia. The comparative analgesic effectiveness and relative rankings of these adjuvants are unknown. This network meta-analysis (NMA) sought to evaluate the comparative analgesic efficacy and relative ranking of caudal adjuvants added to local anesthetics (versus local anesthetics alone) in pediatric infra-umbilical surgery. We searched the United States National Library of Medicine database (MEDLINE), PubMed, and Excerpta Medica database (Embase) for randomized controlled trials (RCTs) comparing caudal adjuvants (clonidine, dexmedetomidine, ketamine, magnesium, morphine, fentanyl, tramadol, dexamethasone, and neostigmine) among themselves, or to no adjuvant (control). We performed a frequentist NMA and employed Cochrane's 'Risk of Bias' tool to evaluate study quality. We chose the duration of analgesia (defined as 'the time from caudal injection to the time of rescue analgesia') as our primary outcome. We also assessed the number of analgesic dose administrations and total dose of acetaminophen within 24 h. The duration of analgesia [87 randomized control trials (RCTs), 5285 patients] was most prolonged by neostigmine [mean difference: 513 min, (95% confidence interval, CI: 402, 625)]. Dexmedetomidine reduced the frequency of analgesic dose administrations within 24 h [29 RCTs, 1765 patients; -1.2 dose (95% CI: -1.6, -0.9)] and the total dose of acetaminophen within 24 h [18 RCTs, 1156 patients; -350 mg (95% CI: -467, -232)] the most.  Among caudal adjuvants, neostigmine (moderate certainty), tramadol (low certainty), and dexmedetomidine (low certainty) prolonged the duration of analgesia the most. Dexmedetomidine also reduced the analgesic frequency and consumption more than other caudal adjuvants (moderate certainty).

Comparison of adjuvant pharmaceuticals for caudal block in pediatric lower abdominal and urological surgeries: A network meta-analysis

STUDY OBJECTIVE

Caudal block helps relieve pain after sub-umbilical surgery in pediatric patients; however, the duration for which it exerts its analgesic effect is limited. The addition of certain adjuvant agents to local anesthetics (LAs) that are used to administer caudal block can prolong postoperative analgesia. Therefore, we aimed to compare the efficiencies and side effects of caudal adjuvants in the settings of pediatric lower abdominal and urological surgeries.

DESIGN

A network meta-analysis (NMA).

PATIENTS

One hundred and twelve randomized controlled trials (RCTs) involving 6800 pediatric patients were included in the final analysis.

INTERVENTIONS

Different adjuvant agents, namely clonidine, dexamethasone, dexmedetomidine, fentanyl, ketamine, magnesium, midazolam, morphine, neostigmine, and tramadol.

MEASUREMENTS

The primary outcome was the duration of analgesia. The secondary outcomes included the requirement for additional analgesia, analgesic consumption, and postoperative complications. The effects and rankings were evaluated using NMA and the surface under the cumulative ranking curve scores, respectively.

RESULTS

Neostigmine, dexmedetomidine, and dexamethasone were found to be the three most effective adjuvants that prolong the duration of analgesia for caudal block, and these adjuvants extended this duration by 8.9 h (95% confidence interval [CI], 7.1-10.7), 7.3 h (95% CI, 6.0-8.6), and 5.9 h (95% CI, 4.0-7.7), respectively. Caudal neostigmine was associated with an increase in the incidence of postoperative nausea and vomiting, whereas dexmedetomidine and dexamethasone showed no postoperative complications.

CONCLUSIONS

This NMA provided evidence and suggested that dexmedetomidine and dexamethasone may be the most beneficial adjuvant pharmaceutics adding to LAs for caudal block in children. However, given the off-label status of caudal dexmedetomidine and dexamethasone, further high-quality RCTs are still warranted, especially to determine whether delayed neurological complications will occur.

Effect of intra-articular dexmedetomidine on experimental osteoarthritis in rats

Pharmacological treatment of osteoarthritis is still inadequate due to the low efficacy of the drugs used. Dexmedetomidine via the intra-articular (i.a.) route might be an option for the treatment of osteoarthritis-associated pain. The present study assessed the analgesic and anti-inflammatory effects of dexmedetomidine administered via the i.a. route in different doses in an experimental model of rat knee osteoarthritis induced with monosodium iodoacetate. Rats were allocated to four groups with 24 animals in each group. The OA (osteoarthritis), DEX-1 (dexmedetomidine in dose of 1μg/kg) and DEX-3 (dexmedetomidine in dose of 3μg/kg) groups were subjected to induction of osteoarthritis through injection of monosodium iodoacetate (MIA) via the i.a. route on the right knee; the control group was not subjected to osteoarthritis induction. Clinical assessment was performed on day 0 (before osteoarthritis induction) and then on days 5, 10, 14, 21 and 28 after induction. Treatment was performed on day 7 via the i.a. route, consisting of dexmedetomidine in doses of 1 and 3 μg/kg, while group OA received 0.9% normal saline. The animals were euthanized on days 7, 14, 21 and 28. Samples of the synovial membrane were collected for histopathological analysis, and the popliteal lymph nodes were collected for measurement of cytokines (interleukin [IL] IL-6, tumor necrosis factor alpha [TNF-α]). Dexmedetomidine (1 and 3 μg/kg) significantly reduced the animals’ weight distribution deficit during the chronic-degenerative stage of osteoarthritis and improved the pain threshold throughout the entire experiment. Histological analysis showed that dexmedetomidine did not cause any additional damage to the synovial membrane. The TNF-α levels decreased significantly in the DEX-3 group on day 28 compared with the OA group. Dexmedetomidine reduced pain, as evidenced by clinical parameters of osteoarthritis in rats, but did not have an anti-inflammatory effect on histological evaluation.

Caudal dexmedetomidine in pediatric caudal anesthesia: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To evaluate the efficacy and safety of caudal dexmedetomidine in pediatric caudal anesthesia (CA).

METHODS

We searched PubMed, Embased, and Cochrane Library (from inception to June 2019) for eligible studies. The primary outcomes were the time to first analgesia, time of postoperative eye opening, intraoperative endtidal sevoflurane concentration, and postoperative sedation score. We calculated pooled risk ratios (RR) and 95% CIs using random- or fixed-effects models.

RESULTS

Thirteen trials involving 793 patients were found. Meta-analysis showed that the time to first rescue pain medication and the time from the end of anesthesia to eye opening in the CA+dexmedetomidine group were significantly longer than in the CA group (P < .00001). The intraoperative end-tidal sevoflurane concentration in the CA+dexmedetomidine group was significantly decreased (P < .00001). Dexmedetomidine appeared to increase the rate of bradycardia in the CA+dexmedetomidine group (P = .04). Additionally, the sedation score in the CA+ dexmedetomidine group was significantly higher at 2 hours after the operation compared with the CA group (P < .00001 at 2 hours).

CONCLUSIONS

Caudally administered dexmedetomidine is a good alternative for prolonging postoperative analgesia with less pain, decreased intraoperative end-tidal sevoflurane concentration, and full postoperative sedation.

A Randomized Controlled Trial Study on the Effect of Adding Dexmedetomidine to Bupivacaine in Supraclavicular Block Using Ultrasound Guidance

Background

The benefits of regional anesthetic techniques are well established. Use of additives to local anesthetics can prolong these benefits. The aim of this study was to find out the effect of adding dexmedetomidine to bupivacaine for supraclavicular block.

Methods

In this randomized, double-blind study, 70 ASA I & II patients of either sex undergoing elective surgeries on the upper limb were given supraclavicular block under ultrasound guidance. Group C (n=35) received 38 mL 0.25% bupivacaine + 2mL normal saline and group D received 38 mL 0.25% bupivacaine + 1 µg/kg dexmedetomidine (2mL). Patients were observed for, onset of motor and sensory block, duration of motor and sensory block, duration of analgesia, sedation score, hemodynamic changes and any adverse events.

Results

In group D, the onset was faster (P< 0.001), durations of sensory and motor block duration of and analgesia were prolonged as compared to group C (P < 0.0001).There was a significant drop in heart rate (HR) from the baseline in group D (P < 0.05) at 30, 60, 90 and 120 min. However, none of the patients dropped HR below 50/min. Mean Arterial Pressure (MAP) remained unaffected. The patients in group D were more effectively sedated than those in group C (P < 0.05). No adverse event was reported in either group.

Conclusion

Dexmedetomidine as adjuvant to bupivacaine in supraclavicular block resulted in faster action, prolonged motor and sensory block, prolonged analgesia with hemodynamic stability and adequate sedation.

Comparison of Two Doses of Dexmedetomidine for Supraclavicular Brachial Plexus Block: A Randomized Controlled Trial

Background:

Dexmedetomidine is commonly used as an additive in supraclavicular brachial plexus block (SBPB). Due to its adverse effects such as bradycardia and hypotension, finding the appropriate dose of dexmedetomidine is the question.

Aims:

We aimed to compare two commonly used doses of dexmedetomidine (1 μg/kg and 2 μg/kg) added to levobupivacaine in ultrasound-guided SBPB in terms of its effect on duration of analgesia, hemodynamics, and associated adverse effects.

Settings and Design:

This randomized, double-blinded prospective study was conducted over a period of 1.5 years in our tertiary care hospital.

Materials and Methods:

Clearance from the Institutional Ethical Committee and Clinical Trial Registry of India was taken. Ninety patients' physical status American Society of Anesthesiologists Classes I and II undergoing upper limb surgeries under SBPB were included in this study. Patients in Group I received 1 μg/kg dexmedetomidine, whereas patients in Group II received 2 μg/kg dexmedetomidine added to 20 cc levobupivacaine. The primary outcome measure was the duration of analgesia after administering the block. Secondary outcomes included effect on hemodynamics, duration of blockade, and adverse effects.

Statistical Analysis:

Statistical analysis was carried out using Stata Version 10. Unpaired t-test and Chi-square test were used.

Results:

The duration of analgesia and sensory and motor blockade were similar in both the groups. The heart rate (HR) and mean arterial pressure were statistically lower in Group II. The incidence of bradycardia and hypotension was more in Group II.

Conclusions:

Increasing the dose of dexmedetomidine does not prolong the duration of analgesia, but it is associated with lower HR and blood pressure. Incidence of hypotension and bradycardia is also more. Hence, a lower dose of 1 μg/kg dexmedetomidine added to 0.5% levobupivacaine is a good balance between safety and efficacy.

Comparison of caudal ropivacaine-morphine and paravertebral catheter for major upper abdominal surgery in infants

BACKGROUND

The caudal epidural block is one of the most commonly used regional anesthetic techniques in children. Administration of morphine via caudal injection enables analgesia, even for upper abdominal surgery. The thoracic paravertebral block has also been successfully used to treat perioperative pain during upper abdominal procedures in pediatric patients.

AIM

In the current study, we compared the two regional techniques for upper abdominal surgery in infants to determine whether one of them was preferable to the other.

METHODS

Consecutive patients under 12 months of age who underwent upper abdominal surgery were retrospectively divided according to the chosen postoperative analgesia: Group C, caudal ropivacaine-morphine; Group P, paravertebral catheter. We analyzed the following outcomes: requirement for additional analgesics, pain scores, need for mechanical ventilation and oxygen dosage, postoperative blood pressure and heart rate, time to pass first stool, time until first full meal, and complications.

RESULTS

Twenty-one consecutive patients were included: 10 in Group C and 11 in Group P. Median age at surgery was 80 (47.5-270.0) and 84.5 (34.3-287.5) days, respectively. No difference was found between the two groups in requirement for additional analgesics at 24 h after surgery (median 1 in Group C vs 1 in Group P, P = 0.288, 95% CI: -2 to 1). BOPS pain scores were only lower in Group P when compared to Group C at 24 h after surgery (median 1 vs 2, P = 0.041, 95% CI: -2 to 0). None of the patients had perioperative complications.

CONCLUSIONS

In this small series, there was no significant difference between caudal ropivacaine-morphine and paravertebral catheter for postoperative care in infants undergoing upper abdominal surgery. Further prospective studies are needed to compare the efficacy and incidence of complications of caudal block and paravertebral catheter for postoperative analgesia.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Effect of dexmedetomidine as an adjuvant to bupivacaine in femoral nerve block for perioperative analgesia in patients undergoing total knee replacement arthroplasty: A dose-response study

Context:

Dexmedetomidine is being increasingly used in nerve blocks. However, there are only a few dose determination studies.

Aims:

To compare two doses of dexmedetomidine, in femoral nerve block, for postoperative analgesia after total knee arthroplasty (TKA).

Settings and Design:

A prospective, randomized, controlled trial was conducted in the Department of Anesthesia at AIIMS, a Tertiary Care Hospital.

Materials and Methods:

Sixty American Society of Anesthesiologists I–II patients undergoing TKA under subarachnoid block were randomized to three Groups A, B, and C. Control Group A received 20 ml (0.25%) of bupivacaine in femoral nerve block. Groups B and C received 1 and 2 μg/kg dexmedetomidine along with bupivacaine for the block, respectively. Outcomes measured were analgesic efficacy measured in terms of visual analog scale (VAS) score at rest and passive motion, duration of postoperative analgesia, and postoperative morphine consumption. Adverse effects of dexmedetomidine were also studied.

Statistical Analysis Used:

All qualitative data were analyzed using Chi-square test and VAS scores using Kruskal–Wallis test. Comparison of patient-controlled analgesia (PCA) morphine consumption and time to first use of PCA were done using ANOVA followed by Least Significant Difference test. A P < 0.05 was considered statistically significant.

Results:

The VAS score at rest was significantly lower in Group C compared to Groups A and B (P < 0.05). There was no difference in VAS score at motion between Groups B and C. The mean duration of analgesia was significantly longer in Group C (6.66 h) compared to Groups A (4.55 h) and B (5.70 h). Postoperative mean morphine consumption was significantly lower in Group C (22.85 mg) compared to Group A (32.15 mg) but was comparable to Group B (27.05 mg). There was no significant difference in adverse effects between the groups.

Conclusion:

The use of dexmedetomidine at 2 μg/kg dose in femoral nerve block is superior to 1 μg/kg for providing analgesia after TKA, although its role in facilitating early ambulation needs further evaluation.

A comparative study of dexmedetomidine and fentanyl as adjuvants to levobupivacaine for caudal analgesia in children undergoing lower limb orthopedic surgery

Background:

Levobupivacaine is an effective local anesthetic agent with less systemic toxicity than racemic bupivacaine, but it has short postoperative analgesic duration. Dexmedetomidine and fentanyl are promising adjuncts to provide excellent and prolonged postoperative caudal analgesia. This study compared the effects of caudal levobupivacaine plus dexmedetomidine and levobupivacaine plus fentanyl for postoperative analgesia and sedation in children undergoing lower limb orthopedic surgery.

Patients and Methods:

Ninety children, whose age ranged from 1 to 7 years, American Society of Anesthesiologists I-II, undergoing orthopedic lower limb surgery under general anesthesia received caudal block for postoperative analgesia. The children were randomly allocated into three groups: Group L (control) received 0.75 ml/kg levobupivacaine 0.25% diluted in saline; Group LD received 0.75 ml/kg levobupivacaine 0.25% with dexmedetomidine 1 μg/kg; and Group LF received 0.75 ml/kg levobupivacaine 0.25% with fentanyl 1 μg/kg. Following the administration of the drugs; hemodynamic variables, the total anesthesia time, sedation score, Face, Legs, Activity, Cry, Consolability score, duration of analgesia, and side effects were recorded.

Results:

Demographically, all the groups were comparable, both the baseline and the intraoperative hemodynamic profile were similar in all groups. The mean duration of analgesia and the mean sedation score in the Group LD were significantly greater as compared to both the other groups.

Conclusion:

Dexmedetomidine may be a better additive to levobupivacaine than fentanyl for caudal postoperative analgesia, arousable sedation with comparable hemodynamic and side effect profile in children.

Efficacy of dexmedetomidine on postoperative nausea and vomiting: a meta-analysis of randomized controlled trials

PURPOSE

Postoperative nausea and vomiting (PONV) is a frequent complication in postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on PONV.

METHODS

Two researchers independently searched PubMed, Embase and Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs). The meta-analysis was performed with Review Manager.

RESULTS

Eighty-two trials with 6,480 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative nausea (Risk Ratio (RR) = 0.61, 95% confidence interval (CI): 0.50 to 0.73) and vomiting (RR = 0.48, 95% CI: 0.36 to 0.64) compared with placebo, with an effective dose of 0.5 ug/kg (RR = 0.46, 95% CI: 0.34 to 0.62) and 1.0 ug/kg (RR = 0.29, 95% CI: 0.12 to 0.75), respectively. The antiemetic effect can only be achieved intravenously, not epidurally or intrathecally. The efficacy of dexmedetomidine was similar to that of widely used agents, such as propofol, midazolam etc., but better than opioid analgesics. Moreover, application of dexmedetomidine reduced intraoperative requirement of fentanyl (Standard Mean Difference = -1.91, 95% CI: -3.20 to -0.62).

CONCLUSIONS

The present meta-analysis indicates that dexmedetomidine shows superiority to placebo, but not to all other anesthetic agents on PONV. And this efficacy may be related to a reduced consumption of intraoperative opioids.

Single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery: a meta-analysis of randomised placebo-controlled studies

OBJECTIVES

To evaluate the efficacy and safety of single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery.

DESIGN

Meta-analysis.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

A comprehensive literature search, using Medline (1966-2014), the Cochrane Central Register of Controlled Trials and Embase databases, was conducted to identify randomised placebo-controlled trials that used a combination of single-dose intra-articular bupivacaine and morphine for postoperative pain relief.

RESULTS

12 articles were included in this meta-analysis. The mean visual analogue scale (VAS) scores of the bupivacaine plus morphine group were significantly lower than those of the placebo group (weighted mean difference (WMD) -1.75; 95% CI -2.16 to -1.33; p<0.001). The VAS scores at the last follow-up time point (last VAS scores) of the bupivacaine plus morphine group were also significantly lower than those of the placebo group (WMD -1.46; 95% CI -1.63 to -1.29; p<0.001). The number of patients requiring supplementary analgesia was also significantly reduced (RR 0.60; 95% CI 0.39 to 0.93; p=0.02), while there was no significant difference in the time to first analgesic request (WMD 3.46; 95% CI -1.81 to 8.72; p=0.20) or short-term side effects (RR 1.67; 95% CI 0.65 to 4.26; p=0.29).

CONCLUSIONS

The administration of single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery is effective for pain relief, and its short-term side effects remain similar to saline placebo.

Efficacy of dexmedetomidine on postoperative nausea and vomiting: a meta-analysis of randomized controlled trials

PURPOSE

Postoperative nausea and vomiting (PONV) is a frequent complication in postoperative period. The aim of the current meta-analysis was to assess the efficacy of dexmedetomidine on PONV.

METHODS

Two researchers independently searched PubMed, Embase and Cochrane Central Register of Controlled Trials for randomized controlled trials (RCTs). The meta-analysis was performed with Review Manager.

RESULTS

Eighty-two trials with 6,480 patients were included in this meta-analysis. Dexmedetomidine reduced postoperative nausea (Risk Ratio (RR) = 0.61, 95% confidence interval (CI): 0.50 to 0.73) and vomiting (RR = 0.48, 95% CI: 0.36 to 0.64) compared with placebo, with an effective dose of 0.5 μg/kg (RR = 0.46, 95% CI: 0.34 to 0.62) and 1.0 μg/kg (RR = 0.29, 95% CI: 0.12 to 0.75), respectively. The antiemetic effect can only be achieved intravenously, not epidurally or intrathecally. The efficacy of dexmedetomidine was similar to that of widely used agents, such as propofol, midazolam etc., but better than opioid analgesics. Moreover, application of dexmedetomidine reduced intraoperative requirement of fentanyl (Standard Mean Difference = -1.91, 95% CI: -3.20 to -0.62).

CONCLUSIONS

The present meta-analysis indicates that dexmedetomidine shows superiority to placebo, but not to all other anesthetic agents on PONV. And this efficacy may be related to a reduced consumption of intraoperative opioids.