Dose dependent reduction in median effective concentration (EC50) of ropivacaine with adjuvant dexmedetomidine in labor epidural analgesia: An up-down sequential allocation study

Dose-response of epidural ropivacaine with 0.4 μg mL-1 of dexmedetomidine for labor analgesia: A prospective double-blinded study

BACKGROUND

Studies have shown that the ideal dose of epidural dexmedetomidine is 0.4 μg mL-1 for epidural labor analgesia. However, the appropriate dose of ropivacaine when combined with 0.4 μg mL-1 of dexmedetomidine for epidural labor analgesia is still unknown. Therefore, we aimed to determine the dose-response of ropivacaine when using 0.4 μg mL-1 of dexmedetomidine as epidural adjuvant for labor analgesia.

METHODS

One hundred of nulliparous singleton pregnant patients were randomized allocated into 1 of 5 groups with epidural ropivacaine concentration of 0.05%, 0.0625%, 0.075%, 0.0875%, and 0.1%. Labor analgesia was initialed with 12 mL of the mixed study solution. Effective analgesia was defined as a visual analogue scale <10 mm 30 minutes after the initial epidural bolus. The EC50 and EC95 for epidural ropivacaine was calculated by probit regression.

RESULTS

Ninety-three of parturients were involved into the final analysis. Totals of 63.2% (12/19), 73.7% (14/19), 88.9% (16/18), 94.7% (18/19), and 100% (18/18) of parturients in group 0.05, 0.0625, 0.075, 0.0875, and 0.1 received effective epidural labor analgesia. The calculated EC50 and EC95 of epidural ropivacaine were 0.046% (95% CI 0.028-0.054%) and 0.086% (95% CI 0.074-0.137%), respectively.

CONCLUSIONS

Under the condition of the study, a bolus of 12 mL ropivacaine 0.086% and dexmedetomidine 0.4 μg mL-1 could afford 95% of nulliparous singleton pregnant patients without suffering labor pain after a test dose of lidocaine 45 mg.

The median effective concentration of epidural ropivacaine with different doses of dexmedetomidine for motor blockade: an up-down sequential allocation study

Study objective

Recent studies have shown that dexmedetomidine can be safely used in peripheral nerve blocks and spinal anesthesia. Epidural administration of dexmedetomidine produces analgesia and sedation, prolongs motor and sensory block time, extends postoperative analgesia, and reduces the need for rescue analgesia. This investigation seeks to identify the median effective concentration (EC50) of ropivacaine for epidural motor blockade, and assess how incorporating varying doses of dexmedetomidine impacts this EC50 value.

Design

Prospective, double-blind, up-down sequential allocation study.

Setting

Operating room, post-anesthesia care unit, and general ward.

Interventions

One hundred and fifty patients were allocated into five groups in a randomized, double-blinded manner as follows: NR (normal saline combined with ropivacaine) group, RD0.25 (0.25 μg/kg dexmedetomidine combined with ropivacaine) group, RD0.5 (0.5 μg/kg dexmedetomidine combined with ropivacaine) group, RD0.75 (0.75 μg/kg dexmedetomidine combined with ropivacaine) group, RD1.0 (1.0 μg/kg dexmedetomidine combined with ropivacaine) group. The concentration of epidural ropivacaine for the first patient in each group was 0.5%. Following administration, the patients were immediately placed in a supine position for observation, and the lower limb motor block was assessed every 5 min using the modified Bromage score within 30 min after drug administration. According to the sequential method, the concentration of ropivacaine in the next patient was adjusted according to the reaction of the previous patient: effective motor block was defined as the modified Bromage score > 0 within 30 min after epidural administration. If the modified Bromage score of the previous patient was >0 within 30 min after drug administration, the concentration of ropivacaine in the next patient was decreased by 1 gradient. Conversely, if the score did not exceed 0, the concentration of ropivacaine in the next patient was increased by 1 gradient. The up-down sequential allocation method and probit regression were used to calculate the EC50 of epidural ropivacaine.

Measurements

Adverse events, hemodynamic changes, demographic data and clinical characteristics.

Main results

The EC50 of epidural ropivacaine required to achieve motor block was 0.677% (95% CI, 0.622-0.743%) in the NR group, 0.624% (95% CI, 0.550-0.728%) in the RD0.25 group, 0.549% (95% CI, 0.456-0.660%) in the RD0.5 group, 0.463% (95% CI, 0.408-0.527%) in the RD0.75 group, and 0.435% (95% CI, 0.390-0.447%) in the RD1.0 group. The EC50 of the NR group and the RD0.25 group were significantly higher than that of the RD0.75 and the RD1.0 groups, and the EC50 of the RD0.5 group was significantly higher than that of the RD1.0 group.

Conclusion

The EC50 of epidural ropivacaine required to achieve motor block was 0.677% in the NR group, 0.624% in the RD0.25 group, 0.549% in the RD0.5 group, 0.463% in the RD0.75 group, and 0.435% in the RD1.0 group. Dexmedetomidine as an adjuvant for ropivacaine dose-dependently reduce the EC50 of epidural ropivacaine for motor block and shorten the onset time of epidural ropivacaine block. The optimal dose of dexmedetomidine combined with ropivacaine for epidural anesthesia was 0.5 μg/kg.

Randomized Double-Blind Study of the Effect of Injectate Temperature on Intrathecal Bupivacaine Dose Requirement in Spinal Anesthesia for Cesarean Delivery

BACKGROUND

Increasing the temperature of intrathecal local anesthetics has been shown to increase the speed of onset and block height of spinal anesthesia. However, how this influences dose requirement has not been fully quantified. The aim of this study was to determine and compare the effective dose for anesthesia for cesarean delivery in 50% of patients (ED50) of intrathecal bupivacaine given at temperatures of 37 °C (body temperature) or 24 °C (room temperature).

METHODS

Eighty healthy parturients having elective cesarean delivery under combined spinal-epidural anesthesia were randomly assigned to receive intrathecal hyperbaric bupivacaine stored at 37 °C (body temperature group) or 24 °C (room temperature group). The first subject in each group received a bupivacaine dose of 10 mg. The dose for each subsequent subject in each group was varied with an increment or decrement of 1 mg based on the response (effective or noneffective) of the previous subject. Patients for whom the dose was noneffective received epidural supplementation after data collection with lidocaine 2% as required until anesthesia was sufficient for surgery. Values for ED50 were calculated using modified up-down sequential analysis with probit analysis applied as a backup sensitivity analysis. These values were compared and the relative mean potency was calculated.

RESULTS

The ED50 (mean [95% confidence interval, CI]) of intrathecal hyperbaric bupivacaine was lower in the body temperature group (6.7 [5.7-7.6] mg) compared with the room temperature group (8.1 [7.7-8.6] mg) (P < .05). The relative potency ratio for intrathecal bupivacaine for the room temperature group versus the body temperature group was 0.84 (95% CI, 0.77-0.93).

CONCLUSIONS

Warming hyperbaric bupivacaine to body temperature reduced the dose requirement for spinal anesthesia for cesarean delivery by approximately 16% (95% CI, 7%-23%).

The 50% and 95% effective dose of remimazolam tosilate for anaesthesia induction in sleep disorders patients undergoing laparoscopic cholecystectomy: an up-and-down sequential allocation trial

PURPOSE

Previous reports argue that preoperative sleep conditions of patients can influence the dosage of general anaesthesia drugs. Therefore, we aimed to investigate the dose-effect relationship of preoperative sleep disorders on the induction of general anaesthesia with remimazolam tosilate and calculate the Median effective (ED50) and 95% effective (ED95) dosages.

METHODS

Included in our study were 56 patients who underwent laparoscopic cholecystectomy at our hospital. A separate group of 27 patients with sleep disorders (SD group) and 29 patients without sleep disorders (NSD group) using the Pittsburgh Sleep Quality Index (PSQI) were also included. According to the Dixon 'up-and-down' design, patients received remimazolam at preselected concentrations starting at 0.2 mg/kg. After the administration of remimazolam, loss of consciousness was observed. By observing whether consciousness disappeared within a minute, we adjusted the dose of remimazolam by 0.1 mg/kg (up and down) in the following patient. The Median effective dose (ED50), 95% effective dose (ED95), and 95% confidence interval (CI) of remimazolam for effective sedation were calculated.

RESULTS

The ED50 of remimazolam was 0.226 mg/kg (95%CI 0.221-0.232 mg/kg) in the SD group and 0.191 mg/kg (95%CI, 0.183-0.199 mg/kg) in the NSD group. The ED95 of remimazolam was 0.237 mg/kg (95%CI 0.231-0.262 mg/kg) in the SD group and 0.209 mg/kg (95%CI 0.200-0.254 mg/kg) in the NSD group.

CONCLUSIONS

In the SD group, the ED50 and ED95 of remimazolam during anaesthesia induction were 0.226 and 0.237 mg/kg, respectively. The induction dose of remimazolam in the SD group was significantly higher than that in the NSD group.

Clinical Use of Adrenergic Receptor Ligands in Acute Care Settings

In this chapter, we review how ligands, both agonists and antagonists, for the major classes of adrenoreceptors, are utilized in acute care clinical settings. Adrenergic ligands exert their effects by interacting with the three major classes of adrenoceptors. Adrenoceptor agonists and antagonists have important applications, ranging from treatment of hypotension to asthma, and have proven to be extremely useful in a variety of clinical settings of acute care from the operating room to the critical care environment. Continued research interpreting the mechanisms of adrenoreceptors may help the discovery of new drugs with more desirable clinical profiles.

Application of Dexmedetomidine in Epidural Labor Analgesia: A Systematic Review and Meta-Analysis on Randomized Controlled Trials

OBJECTIVES

To summarize and appraise the use of dexmedetomidine in epidural labor analgesia, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

We conducted the literature search about the RCTs of epidural labor analgesia with or without dexmedetomidine from inception until November 1, 2022, in the following databases: PubMed, Cochrane Library, and Embase. The primary outcome was visual analog scale (VAS) within 2 hours after epidural intubation. The secondary outcomes included the duration of the first and second labor stages, Apgar score, umbilical blood pH, dosage of analgesics, and side effects.

RESULTS

Eight RCTs including 846 parturients were included. The VAS score of the dexmedetomidine group was significantly lower than that of the control group at the time of 15 minutes (mean difference [MD] -1.41, 95% confidence interval [CI] -2.23, -0.59), 30 minutes (MD -1.02, 95% CI -1.70, -0.33), 60 minutes (MD -0.90, 95% CI -1.36, -0.44), and 90 minutes (MD -0.70, 95% CI -1.16, -0.23). The incidence of pruritus in the dexmedetomidine group was lower than that of the control group （MD 0.28, 95% CI 0.11, 0.74), but the incidence of maternal bradycardia was higher (MD 6.41, 95% CI 1.64, 25.04). There were no significant difference in other outcomes.

DISCUSSION

Dexmedetomidine combined with local anesthetic for epidural labor analgesia can improve the VAS score of parturients. Except for the increased incidence of maternal bradycardia, it seems to be safe for the parturients and fetuses.

A randomized double-blinded study assessing the dose-response of ropivacaine with dexmedetomidine for maintenance of labor with epidural analgesia in nulliparous parturients

Background: The combination of ropivacaine and dexmedetomidine has been used as an epidural analgesic for inducing labor. However, there is limited data regarding the administration of epidural analgesia for labor maintenance, hence, this study aimed to determine the optimum concentration through dose-response curves of ropivacaine plus dexmedetomidine, which could be used along with the Programmed Intermittent Epidural Bolus (PIEB) technique. Methods: One hundred parturients were randomized into 4 groups who were administered four different doses of ropivacaine (dexmedetomidine at 0.4 μg mL-1): 0.04%, 0.06%, 0.08%, and 0.1%. The primary outcome that was determined included the proportion of patients experiencing breakthrough pain during their 1st stage of labor. Breakthrough pain was described as a visual analog scale [VAS] score of >30 mm, requiring supplemental epidural analgesia after the administration of at least one patient-controlled bolus. The effective concentration of analgesia that was used for labor maintenance in 50% (EC50) and 90% (EC90) of patients were calculated with the help of probit regression. Secondary outcomes included epidural block characteristics, side effects, neonatal outcomes, and patient satisfaction. Results: The results indicated that the proportion of patients without breakthrough pain was 45% (10/22), 55% (12/22), 67% (16/24), and 87% (20/23) for 0.04%, 0.06%, 0.08%, and 0.10% doses of the analgesic that were administered, respectively. The EC50 value was 0.051% (95% confidence interval [CI], 0.011%-0.065%) while the EC90 value was recorded to be 0.117% (95% CI, 0.094%-0.212%). Side effects were similar among groups. Conclusion: A ropivacaine dose of 0.117% can be used as epidural analgesia for maintaining the 1st stage of labor when it was combined with dexmedetomidine (0.4 μg mL-1) and the PIEB technique. Clinical Trial Register: https://www.chictr.org.cn/index.aspx, identifier ChiCTR2200059557.

Low-dose intranasal dexmedetomidine premedication improves epidural labor analgesia onset and reduces procedural pain on epidural puncture: a prospective randomized double-blind clinical study

BACKGROUND

Epidural labor analgesia is a safe and effective method of pain management during labor with the drawbacks of delayed onset and maternal distress during epidural puncture. This study aimed to determine whether pretreatment with intranasal low-dose dexmedetomidine effectively shortens the onset of analgesia and reduces procedural pain.

METHODS

In this prospective, randomized double-blind trial, nulliparous patients were randomly assigned to either the intranasal dexmedetomidine group or the control group. The intranasal dexmedetomidine group received 0.5 μg/kg dexmedetomidine intranasally, and the control group received an equal volume of normal saline intranasally. Both groups were maintained with a programmed intermittent epidural bolus. The primary outcome was the onset time of analgesia and scores of pain related to the epidural puncture.

RESULTS

Seventy-nine patients were enrolled, and 60 completed the study and were included in the analysis. The time to achieve adequate analgesia was significantly shorter in the intranasal dexmedetomidine group than in the control group (hazard ratio = 2.069; 95% CI, 2.187 to 3.606; P = 0.010). The visual analogue scale pain scores during epidural puncture in the intranasal dexmedetomidine group were also significantly lower than those in the control group (2.0 (1.8-2.5) vs. 3.5 (3.3-4.5), P ≤ 0.001, Table 2). Pretreatment with intranasal dexmedetomidine before epidural labor analgesia was associated with improved visual analogue scale pain scores and Ramsay scores, less consumption of analgesics and higher maternal satisfaction (P < 0.05). No differences were observed for labor and neonatal outcomes or the incidence of adverse effects between the two groups.

CONCLUSIONS

Pretreatment with intranasal dexmedetomidine before epidural labor analgesia yielded a faster onset of analgesia and decreased epidural puncture pain without increasing adverse effects. Pretreatment with intranasal dexmedetomidine may be a useful adjunct for the initiation of epidural analgesia, and further investigation should be encouraged to determine its utility more fully.

TRIAL REGISTRATION

This trial was prospectively registered at Chictr.org.cn on 29/05/2020 with the registration number ChiCTR2000033356 ( http://www.chictr.org.cn/listbycreater.aspx ).

Comparison of Efficacy and Safety of Different Doses of Dexmedetomidine for Epidural Labor Analgesia

Objective

To explore the efficacy and safety of different doses of dexmedetomidine (DEX) for epidural labor analgesia (ELA).

Methods

From June 2021 to June 2022, 147 parturients who underwent ELA in our hospital were selected and divided into low- (0.5 μg/kg DEX), medium- (0.75 μg/kg DEX), and high-dose (1.0 μg/kg DEX) groups (n = 49 for each) according to the random number table method. The analgesic effect was assessed using the Ramsay sedation score and Visual Analogue Scale (VAS), and the labor duration, mean arterial pressure (MAP), and heart rate (HR) before and after analgesia, vaginal bleeding within 2 h postpartum, and delivery outcomes (the cesarean section conversion rate and the neonatal Apgar score) were statistically analyzed. Furthermore, the incidence of adverse reactions was calculated, and maternal satisfaction with delivery was investigated.

Results

After analgesia, the the Ramsay and labor duration were higher in the high-dose group than those in the low- and medium-dose groups, and the VAS scores was lowerin the high-dose group than those in the low- and medium-dose groups(P < 0.05), while no difference was identified among the three groups in terms of the cesarean section conversion rate and the neonatal Apgar score (P > 0.05). The high-dose group had the greatest fluctuations in MAP and HR levels before and after analgesia than the other two groups, with a higher incidence of adverse reactions (P < 0.05). Finally, the survey of delivery satisfaction showed no significant difference in delivery satisfaction among the three groups (P > 0.05).

Conclusion

DEX has excellent performance in ELA, which can effectively relieve the pain of puerperae and shorten the labor process. Among them, low-dose DEX has higher safety and is recommended as the first choice. Trial Registrations. This trial is registered with ML2021073.

Comparison of epidural dexmedetomidine to fentanyl in reducing ropivacaine dose in Programmed Intermittent Epidural Bolus plus Patient Controlled Epidural Analgesia during labor: A randomized, double-blind, controlled study

Background

Dexmedetomidine has been documented to reduce the dose of both intrathecal local anesthetic during cesarean delivery, and the concentration of ropivacaine needed for inducing analgesia during labor. However, few studies have compared adjuvant dexmedetomidine to fentanyl on how they impact the dose of ropivacaine required during labor. The aim of the current study was to evaluate the efficacy of epidural dexmedetomidine at doses of 0.3, 0.4, or 0.5 and 2 μg/ml of fentanyl (the traditional clinical concentration), when added to epidural 0.125% ropivacaine.

Methods

This was a randomized, double-blinded study that comprised one hundred eighty-eight patients, allocated into four groups receiving either epidural fentanyl at 2 μg/ml, or dexmedetomidine at 0.3, 0.4, or 0.5 μg/ml for labor analgesia. The primary outcome was the amount of ropivacaine necessary per hour. Secondary outcomes included visual analogue pain scale (VAS), motor block (Bromage Scale), side effects, patient satisfaction, and neonatal outcomes.

Results

At the completion of the study, data from 165 participants were analyzed. The mean hourly amount of epidural ropivacaine administered was 16.2 ± 3.3, 14.0 ± 3.1, 13.1 ± 3.7 and 12.1 ± 2.5 ml/h in the 2 μg/ml fentanyl group, and the 0.3, 0.4 and 0.5 μg/ml dexmedetomidine groups, respectively. There was a significant difference among groups in the mean hourly consumption of epidural ropivacaine (P < 0.0001 for 1 way ANOVA). The frequency of PCEA (patient-controlled epidural analgesia) was significantly higher in the fentanyl group than in the three dexmedetomidine groups (P < 0.001), and similar among the dexmedetomidine groups. The mean values of the VAS among all groups were similar over time, P > 0.05. The incidence of pruritus in the fentanyl group was 17.5%, whereas no patient experienced pruritus in any of the dexmedetomidine groups, P < 0.0001.

Conclusion

The study demonstrated that epidural dexmedetomidine (0.3 and 0.4 μg/ml) was superior to standard dose epidural fentanyl in reducing the mean hourly amount of ropivacaine administered, and minimizing opioid-related side effects. Further large and multicenter studies would be necessary to confirm the benefits of dexmedetomidine, and potentially serve as an alternative to opioids for routine use in labor analgesia.

Clinical trial registration

[http://www.chictr.org.cn/showproj.aspx?proj=62846], identifier [ChiCTR2000039067].

Neuraxial labor analgesia: is there a place for neuraxial adjuvants beyond opioids

Neuraxial labor analgesia is considered the gold standard technique for analgesia. Ideally, a good neuraxial technique uses dilute local anesthetic solutions to produce effective pain relief with no or minimal motor impairment. Adjuvant drugs that are co-administered with the local anesthetic either epidurally or intrathecally are useful in achieving this goal. The current review focuses on the effectivity and side-effect profile of various commonly used or tested adjuvants.

Dexmedetomidine Can Enhance PINK1/Parkin-Mediated Mitophagy in MPTP-Induced PD Mice Model by Activating AMPK

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Our previous study has shown that dexmedetomidine (Dex) can protect mitochondrial function and reduce apoptosis in MPP⁺-induced SH-SY5Y cells. Evidences have shown that mitophagy is related to the development of PD. In this study, we investigated whether Dex can enhance mitophagy in MPTP-induced mice to play a neuroprotective effect. In our experiment, mice were injected with MPTP 30 mg/kg intraperitoneally for 5 consecutive days to establish a PD subacute model. Dex (30, 50, and 100 μg/kg) was injected intraperitoneally 30 minutes before each injection of MPTP, respectively. Our results showed that Dex (50 μg/kg) most significantly attenuated MPTP-induced motor dysfunction and restored TH-positive neurons in the SN, increased the expression of the antiapoptotic protein Bcl-2, and decreased the expression of apoptotic proteins cleaved casepase3, cleaved casepase9, and Bax. Moreover, Dex increased the activity of mitochondrial Complexes I-IV and decreased the level of oxidative stress, manifesting as decreased MDA levels and increased SOD and GSH-PX levels. Besides, under transmission electron microscopy, Dex increased the mitophagosome which is an autophagosome with a mitochondrion-like structure inside under the electron microscope. In addition, Dex could also increase the expression of mitophagy-related proteins p-AMPK, LC3II/I, PINK1, and Parkin and decrease P62. However, after using Compound C (CC, 10 mg/kg, AMPK inhibitor), the effects of Dex on increasing PINK1/Parkin-induced mitophagy and neuroprotection were attenuated. In conclusion, Dex may improve mitochondrial function by activating AMPK to enhance PINK1/Parkin-induced mitophagy, thereby protecting dopaminergic neurons.

Effect of Dexmedetomidine Combined with Ropivacaine on Cognitive Dysfunction and Inflammatory Response in Patients Undergoing Craniocerebral Surgery

Objective

To study the effects of dexmedetomidine in combination with ropivacaine in patients undergoing craniocerebral surgery and their efficiency on cognitive function and inflammatory response of patients.

Methods

100 patients undergoing craniocerebral surgery in our hospital from November 2018 to September 2020 were randomly selected and divided into a control group and an experimental group by drawing lots, with 50 cases in each group. Patients in the control group received routine anesthesia, while those in the experimental group received 1 μg/kg of dexmedetomidine combined with 0.5% of ropivacaine for anesthesia to compare the anesthesia onset time, analgesic time, postoperative awake time, Social Disability Screening Schedule (SDSS) cognitive function score after waking, visual analogue scale (VAS) pain score, Ramsay sedation score, incidence of adverse reactions, postoperative inflammatory factor expression levels, and changes in heart rate, oxygen saturation, and blood pressure at T0, T1, T2, T3, and T4 between the two groups.

Results

The anesthesia onset time, SDSS cognitive function score after waking, VAS pain score, Ramsay sedation score, incidence of adverse reactions, and postoperative inflammatory factor expression levels in the experimental group were significantly lower than those in the control group (P < 0.05). The analgesic time and postoperative awake time in the experimental group were significantly longer than those in the control group, with statistical significance (P < 0.05). There were no statistically significant differences in the changes of heart rate, oxygen saturation, and blood pressure at T0, T1, T2, T3, and T4 between the two groups (P > 0.05).

Conclusion

Dexmedetomidine combined with ropivacaine has high application value in craniocerebral surgery.

Effect of Epidural Dexmedetomidine as an Adjuvant to Local Anesthetics for Labor Analgesia: A Meta-Analysis of Randomized Controlled Trials

Background

This study aims to determine the analgesic effect and safety of dexmedetomidine as an adjuvant to epidural local anesthetics during labor.

Methods

Randomized controlled trials comparing epidural blocks with or without dexmedetomidine for labor analgesia were comprehensively searched. Review manager 5.4 was used to analyze the extracted data.

Results

Compared with placebo and opioids, dexmedetomidine relieved labor pain of 15 min (P=0.002), 30 min (P=0.01), and 120 min (P=0.02) after block and at the moment of fetal disengagement (P=0.0002), decreased mean arterial pressure of 120 min (P=0.01), heart rate of 30 min (P=0.003), 60 min (P < 0.00001), and 120 min (P < 0.00001) after block, blood loss (P=0.02), and the incidence of nausea/vomiting (P=0.006), and increased the incidence of maternal bradycardia (P=0.04). However, sensitivity analysis only found that the incidence of nausea/vomiting was significantly different. Compared with placebo, dexmedetomidine relieved labor pain of 30 min after block (P < 0.00001) and did not increase the incidences of side effects, but only two studies were enrolled. Compared with opioids, dexmedetomidine decreased the incidence of nausea/vomiting (P=0.002), increased the incidence of maternal bradycardia (P=0.04), and had a similar effect on labor pain relief; however, sensitivity analysis found that significant difference existed only at the incidence of nausea/vomiting. Other outcomes from meta-analysis or subgroup analysis were not different.

Conclusions

Epidural dexmedetomidine has the potential to offer a better analgesic effect than placebo, similar labor pain control to opioids, and has no definite adverse effects on the parturient or fetus, but more high-quality studies are needed to confirm these conclusions.

Obesity decreases the EC50 of epidural ropivacaine when combined with dexmedetomidine for labor analgesia

OBJECTIVES

This study aims to estimate the EC50 of ropivacaine when co-administered with dexmedetomidine for epidural labor analgesia in antepartum obese and non-obese parturients.

METHODS

Sixty parturients scheduled for epidural labor analgesia were enrolled and divided into antepartum obesity (AO) and control (CON) groups, according to their body mass index at labor. Both groups received 0.5 µg/mL dexmedetomidine with ropivacaine as anesthetics. The concentration of ropivacaine was initially set at 0.125% and varied by 0.01% according to the up-and-down rule for sequential allocation. Hemodynamic parameters were monitored and pain intensity was assessed using a visual analog scale.

RESULTS

When co-administered with dexmedetomidine, the EC50 of ropivacaine was 0.095% (95% confidence interval [CI]: 0.090-0.100%) and 0.070% (95% CI: 0.062-0.076%) in CON and AO groups, respectively. There was a significant difference between the two groups (P < 0.001). EC95 values of ropivacaine were 0.084% (95% CI: 0.077-0.122%) and 0.106% (95% CI: 0.101-0.128%) in AO and CON groups, respectively.

CONCLUSION

Patients with antepartum obese may require decreased ropivacaine concentration for epidural labor analgesia when co-administered with 0.5 µg/mL dexmedetomidine.

Adjuvant Sufentanil Decreased the EC50 of Epidural Ropivacaine for Labor Analgesia in Healthy Term Pregnancy

Objective

The optimal concentration of ropivacaine as epidural labor analgesia combined with sufentanil has not been established. This study aimed to determine the median effective concentration (EC50) of epidural ropivacaine for labor analgesia in healthy term pregnancy when co-administered with sufentanil as an adjuvant or alone.

Patients and Methods

Sixty healthy parturients scheduled for epidural labor analgesia were enrolled in the study. They were divided into a saline group (Group C) and an epidural sufentanil (0.5 µg/mL) group (Group S). The initial concentration of ropivacaine was set at 0.125%, which was then varied by 0.01% using the up-and-down sequential allocation method. The hemodynamics were continuously monitored during delivery. A visual analog scale was used to evaluate the degree of pain. The Ramsay sedation score, duration of the labor stages, the onset of epidural analgesia, and adverse effects were recorded. Neonatal outcomes were evaluated using the Apgar scores and umbilical artery blood gas analysis.

Results

The EC50 of ropivacaine was 0.085% (95% CI, 0.079–0.090%) in Group S and 0.109% (95% CI, 0.105–0.112%) in Group C. The EC95 of ropivacaine was 0.096% (95% CI, 0.090–0.118%) in Group S, and 0.116% (95% CI, 0.113–0.127%) in Group C. The difference between the groups was statistically significant (p < 0.001). The stable hemodynamics, satisfactory analgesia, and good neonatal outcomes were comparable in both groups (P > 0.05).

Conclusion

The EC50 of ropivacaine was reduced by 22% when co-administered with sufentanil for epidural labor analgesia in primipara. (www.chictr.org.cn; registration number: ChiCTR2000039547).