Comparison of the ED50 of intrathecal hyperbaric ropivacaine co-administered with or without intrathecal dexmedetomidine for cesarean section: A prospective, double-blinded, randomized dose-response trial using up-down sequential allocation method

The optimal dose of dexmedetomidine as a 0.59% ropivacaine adjuvant for epidural anesthesia in great saphenous varicose vein surgery, based on hemodynamics and anesthesia efficacy: a randomized, controlled, double-blind clinical trial

Objective

This study aimed to explore the optimal dose of dexmedetomidine as a 0.59% ropivacaine adjuvant for epidural anesthesia on perioperative hemodynamics and anesthesia efficacy in patients undergoing great saphenous varicose vein surgery.

Methods

A total of 90 patients were randomly divided into three groups: 0.25 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED1 group), 0.5 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED2 group), and 0.75 μg/kg dexmedetomidine combined with 0.59% ropivacaine epidural infusion group (ED3 group). Hemodynamics, anesthesia efficiency, and adverse reactions were recorded.

Main results

Compared with the ED1 group, the ED2 group had lower systolic blood pressure at T1-3 (T1, 95%CIs, 6.52-21.93, p < 0.001; T2, 95%CIs, 2.88-18.21, p = 0.004; T3, 95%CIs, 0.49-18.17, p = 0.035), and the diastolic blood pressure at T1-2 was decreased (T1, 95%CIs, 4.55-14.36, p < 0.001; T2, 95%CIs, 0.37-12.17, p = 0.033). Compared with the ED2 group, the ED3 group had higher systolic blood pressure at T1-2 (T1, 95%CIs, 5.90-21.46, p < 0.001; T2, 95%CIs, 2.07-17.55, p = 0.008) and higher diastolic blood pressure at T1-3 (T1, 95%CIs, 2.91-12.81, p = 0.001; T2, 95%CIs, 1.32-13.23, p = 0.011; T3, 95%CIs, 0.14-11.52, p = 0.043). Compared with the ED2 group, the heart rate was significantly decreased at T1-4 in the ED3 group (T1, 95%CIs, 2.25-15.72, p = 0.005; T2, 95%CIs, 2.35-13.82, p = 0.003; T3, 95%CIs, 0.50-9.79, p = 0.025; T4, 95%CIs, 1.46-10.36, p = 0.005). The myocardial oxygen consumption in all three groups was significantly decreased at each time point compared to T0 (p < 0.05 or < 0.001), and no significant between-group differences were detected (P>0.05). Compared with the ED1 group, the anesthesia efficiency of ED2 and ED3 groups was markedly enhanced, but the risk of bradycardia in ED2 and ED3 groups was dramatically increased (6 of 28 [21.4%] vs. 14 of 30 [46.7%] and 14 of 27 [51.9%], p = 0.023), one patient in the ED3 group experienced difficulty urinating, and remaining adverse reactions were mild in all three groups.

Conclusion

A measure of 0.5 μg/kg dexmedetomidine is the optimal dose as a 0.59% ropivacaine adjuvant for epidural anesthesia in patients undergoing great saphenous varicose vein surgery.

Clinical trial registration

http://www.chictr.org.cn/, registration number: ChiCTR2200060619.

Intravenous Bolus of Dexmedetomidine for Treatment of Severe Shivering After Caesarean Delivery Under Combined Spinal-Epidural Anaesthesia: A Randomized Dose-Response Study

Purpose

Shivering occurs frequently after caesarean delivery. The present study aimed to investigate the ED50 and ED95 of an intravenous (i.v.) bolus of dexmedetomidine for treating severe shivering after caesarean delivery under combined spinal-epidural anaesthesia.

Patients and methods

Seventy-five parturients with severe shivering after caesarean delivery were randomized into one of the five groups to receive an i.v. bolus of 0.2 (Group D1), 0.25 (Group D2), 0.3 (Group D3), 0.35 (Group D4) or 0.4 (Group D5) μg/kg of dexmedetomidine. Effectiveness of shivering treatment was defined as a standardized shivering score decreasing to ≤1 within 10 min of dexmedetomidine injection. The ED50 and ED95 were determined by probit regression. Adverse effects were also compared among the groups.

Results

The ED50 and ED95 of i.v. dexmedetomidine to treat severe shivering were 0.23 (95% CI, 0.16-0.26) μg/kg and 0.39 (95% CI, 0.34-0.52) μg/kg, respectively. No difference in the incidence of adverse effects was found between groups.

Conclusion

An i.v. bolus of 0.39 μg/kg of dexmedetomidine will treat 95% of parturients experiencing severe shivering after caesarean delivery.

The 50% effective dose of hydromorphone and morphine for epidural analgesia in the hemorrhoidectomy: a double-blind, sequential dose-finding study

BACKGROUND

Although previous studies have showed that epidural morphine can be used as a complement to local anesthetics for analgesia after postcesarean delivery under spinal anesthesia, there is little known about the analgesic dosage of epidural morphine and hydromorphone for hemorrhoidectomy. Therefore, we conducted this study to examine the potency ratio of hydromorphone to epidural morphine as well as effective analgesic dose for 50% patients (ED50) undergoing elective hemorrhoidectomy.

METHODS

80 patients under elective hemorrhoidectomy with combined spinal and epidural anesthesia(CSEA) in department of anesthesia, Dongguan Tungwah hospital. To assess the ED50, patients were treated with epidural morphine or epidural hydromorphone randomly using a biased coin method-determined dose with a sequential allocation procedure. Following surgery, standardized multimodal analgesia was administered to all patients. A pain response score of ≤ 3 (on a scale of 0-10) was determined to be the effective dose after 24 h following CSEA. The ED50 in both groups were determined using the probit regression and isotonic regression method. We also measured pain intensity by patient interview using a 10 point verbal numeric rating scale prospectively at 6, 12 and 24 h after CSEA, and adverse effects were also noted.

RESULTS

The ED50 was 0.350 mg (95% CI, 0.259-0.376 mg) in hydromorphone group and 1.129 mg (95% CI, 0.903-1.187 mg) in morphine group, respectively, estimated by isotonic regression method. Regression analysis with the probit, the ED50 of epidural hydromorphone was 0.366 mg (95% CI, 0.276-0.388 mg) and epidural morphine was 1.138 mg (95% CI, 0.910-1.201 mg). Exploratory findings showed that there was no difference between the most frequent dosages of epidural hydromorphone or epidural morphine in the occurrence of nausea, vomiting and pruritus. When administered with epidural opioids at ED50 doses or higher, 97.5% (39/40) of epidural morphine patients and 97.5% (39/40) epidural hydromorphone of patients were satisfied with their analgesia.

CONCLUSION

Effective hemorrhoidectomy analgesia requires a 3:1 ratio of epidural morphine to epidural hydromorphone. Both drugs provide excellent patient satisfaction.

Whole-course application of dexmedetomidine as an adjuvant to spinal-epidural anesthesia for cesarean section: A randomized, controlled trial

Background

Dexmedetomidine is known to prolong the analgesic duration of spinal anesthesia, but it can be challenging to achieve further extension without opioids. Therefore, this study aimed to investigate a novel analgesic strategy using dexmedetomidine as an adjuvant to spinal-epidural anesthesia for elective cesarean surgery.

Methods

The study was a randomized, double-blind, controlled trial conducted at a single center. Sixty parturients who underwent elective cesarean were randomly assigned to either group C or group D. Group D received an intrathecal injection of 12.5 mg ropivacaine and 5 μg dexmedetomidine followed by continuous epidural patient-controlled analgesia (PCA) infusion with a total volume of 100 ml, containing 0.2 % ropivacaine and 0.5 μg/kg dexmedetomidine. Group C received an intrathecal injection of 12.5 mg ropivacaine with an equivalent saline placebo followed by a similar PCA infusion, containing 0.2 % ropivacaine and an equivalent saline placebo.

Results

The primary outcome was visual analog scale score on movement at 24 h after surgery. The results showed that the rest and motion pain scores in group D were significantly lower than those in group C at 6 h, 12 h, and 24 h after surgery (P < 0.05), with the differences at 24 h were 5.0 (5.0, 5.0)in group D versus 5.0 (5.0, 6.0) in group C (P = 0.04). Additionally, the time to the first PCA in group D was significantly longer than that in group C (P < 0.05), as well as the time of sensory and motor recovery.

Conclusions

Whole-course application of dexmedetomidine as an adjuvant to spinal-epidural anesthesia could effectively extend the analgesic duration of ropivacaine to 24 h following elective cesarean surgery.

Comparison of the effect of dexmedetomidine intrathecal injection and intravenous infusion on subarachnoid blockade during knee arthroscopy procedures: a randomized controlled trial

BACKGROUND

Comparison of whether intrathecal dexmedetomidine prolongs spinal anesthesia-associated sensorimotor blockade more than intravenous infusion during knee arthroscopy procedures performed under subarachnoid blockade.

METHODS

Ninety patients aged 18-75 years, ASA class I-II, who underwent knee arthroscopy between October 2022 and April 2023 were randomized into intrathecal、intravenous and control groups.Subjects received three modes of administration: an intrathecal group (2 ml of 1% ropivacaine + 1 ml of 5 μg dexmedetomidine, along with intravenous saline infusion), an intravenous group (intrathecal 2 ml of 1% ropivacaine + 1 ml of 0.9% saline, with dexmedetomidine pumped intravenously at a dose of 0.5 μg/kg/h), and a control group (intrathecal 2 ml of 1% ropivacaine + 1 ml of 0.9% saline, along with intravenous saline infusion). Total analgesic duration, duration of sensory and motor blockade, Ramsay sedation score, Visual Analogue Score (VAS) at different postoperative time points, and occurrence of adverse effects were recorded.

RESULTS

The total analgesia duration was significantly longer in the intrathecal group than in the intravenous and control groups (352.13 ± 51.70 min VS 273.47 ± 62.57 min VS 241.41 ± 59.22 min, P < 0.001).The onset of sensory block was shorter in the intrathecal group than in the intravenous and control groups (4 [3-4]min VS 5 [4-5]min VS 5 [4-5]min; P < 0.001);the onset of motor block was shorter in the intrathecal group than in the intravenous group and the control group (5 [4-5]min VS 5 [5-6]min VS 6[5.5-7]min; P < 0.001).Sedation scores were higher in the intravenous group than in the intrathecal and control groups (P < 0.001). At 5 h postoperatively, the VAS score in the intrathecal group was lower than that in the intravenous and control groups (P < 0.001). At 24 h postoperatively, the VAS score in the intrathecal group was lower than that in the control group (P < 0.001). In addition, the incidence of bradycardia was significantly higher in the intravenous group than in the intrathecal and control groups (30%, 6.5%, and 3.4%, respectively; P = 0.018, P = 0.007).

CONCLUSIONS

Intrathecal administration of dexmedetomidine did prolong the total analgesia duration, as well as accelerate the onset of sensory-motor blockade compared with intravenous infusion, and did not result in any hemodynamic instability or other adverse events at the doses studied.

TRIAL REGISTRATION

This single-center, prospective, RCT has completed the registration of the Chinese Clinical Trial Center at 26/09/2023 with the registration number ChiCTR2300076170.

Comparative dose-response study of intrathecal hyperbaric ropivacaine for cesarean delivery in preterm singleton versus twin pregnancies

INTRODUCTION

Previously, we demonstrated that patients with full-term singletons and preterm twins require similar dose of intrathecal hyperbaric ropivacaine. However, these findings may be attributable to enrolled patients with preterm twin pregnancies. In this study, we aimed to determine the intrathecal dose requirements of hyperbaric ropivacaine for twins and singletons at equal gestational ages.

METHODS

We enrolled 75 patients with preterm singletons and 75 patients with preterm twins scheduled for cesarean delivery under combined spinal-epidural anesthesia in this two-arm parallel, randomized, double-blind, dose-response study. Patients with singletons and twins were randomly assigned to receive one of five different doses of hyperbaric ropivacaine: 10, 12, 14, 16, or 18 mg. A probit regression model was used to determine the dose effective in 50% of patients (ED50) and dose effective in 90% of patients (ED90) values. The relative median potency was calculated to compare the ED50 between patients with twins and singletons.

RESULTS

Intrathecal ropivacaine ED50 and ED90 (with 95% CI) in patients with preterm singletons were 9.9 (7.2 to 11.5) mg and 16.8 (14.5 to 22.9) mg, respectively. In patients with preterm twins, these values were 9.2 (95% CI 6.4 to 10.8) mg and 15.6 (95% CI 13.6 to 20.6) mg. Between patients with preterm twins and preterm singletons, the relative potency (ED50 ratios) was 0.933 (95% CI 0.72 to 1.15).

CONCLUSIONS

During preterm gestation, intrathecal hyperbaric ropivacaine dose requirements for scheduled cesarean delivery were not different between patients with twins and singletons.

TRIAL REGISTRATION NUMBER

ChiCTR2100051382.

Intrathecal dexmedetomidine as an adjuvant to plain ropivacaine for spinal anesthesia during cesarean section: a prospective, double-blinded, randomized trial for ED50 determination using an up-down sequential allocation method

BACKGROUND

Intrathecal dexmedetomidine, as an adjuvant to local anesthetics, has been reported to improve the quality of spinal anesthesia and reduce the required local anesthetic dose. However, the optimal dosage regimen for intrathecal dexmedetomidine combined with plain ropivacaine for cesarean section (CS) remains undetermined. The present study aimed to determine the median effective dose (ED50) of intrathecal dexmedetomidine as an adjuvant to plain ropivacaine for spinal anesthesia during CS.

METHODS

Sixty parturients undergoing CS were randomly assigned to either group: plain ropivacaine 8 mg (Group Rop8) or plain ropivacaine 10 mg (Group Rop10). The initial dosage of intrathecal dexmedetomidine in each group was 5 µg. The effective dose was defined as a bilateral sensory block at the level of T6 or above to pinprick attained within 10 min after intrathecal injection, without the need for supplementary intraoperative epidural anesthesia. Effective or ineffective responses were determined, followed by a 1 µg increment or decrement in the dose of intrathecal dexmedetomidine for the next parturient using up-down sequential allocation. ED50 were calculated using probit regression.

RESULTS

The ED50 of intrathecal dexmedetomidine with plain ropivacaine was 5.9 µg (95% confidence interval [CI], 4.9-7.4 µg) in Group Rop8 and 3.1 µg (95% CI, 0.1-4.8 µg) in Group Rop10 (P < 0.05). Hemodynamic stability, side effects, patient satisfaction and neonatal outcomes were comparable between the two groups.

CONCLUSIONS

The present data suggested that the ED50 of intrathecal dexmedetomidine as an adjuvant to 8 mg and 10 mg plain ropivacaine in spinal anesthesia during cesarean section was approximately 6 µg and 3 µg, respectively.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, identifier: ChiCTR2200055928.

Determination of the 95% effective dose of remimazolam tosylate in anesthesia induction inhibits endotracheal intubation response in senile patients

Background and Purpose: The prevalence of elderly patients prompts anesthesiologists to determine the optimal dose of medication due to the altered pharmacokinetics and pharmacodynamics of this population. The present study aimed to determine the 95% effective dose (ED₉₅) of remimazolam tosylate in anesthesia induction to inhibit endotracheal intubation-related cardiovascular reaction in frail and non-frail senile patients. Methods: A prospective sequential allocation dose-finding study of remimazolam tosylate was conducted on 80 elderly patients who received general anesthesia between May and June 2022 at the First Affiliated Hospital of Nanchang University. The initial dose was 0.3 mg/kg. The blood pressure and heart rate fluctuations during intubation were either <20% (negative cardiovascular response) or ≥20% (positive cardiovascular response). If positive, the dose of the next patient was increased by 0.02 mg/kg, while if negative, it was reduced by 0.02 mg/kg according to the 95:5 biased coin design (BCD). The ED₉₅ and 95% confidence intervals (CIs) were determined using R-Foundation isotonic regression and bootstrapping methods. Results: The ED₉₅ of remimazolam tosylate to inhibit the response during tracheal intubation was 0.297 mg/kg (95% CI: 0.231-0.451 mg/kg) and 0.331 mg/kg (95% CI: 0.272-0.472 mg/kg) in frail and non-frail senile patients, respectively. Conculation and Implications: The CI of the two groups overlap, and no difference was detected in the ED₉₅ of remimazolam tosylate in inhibiting endotracheal intubation-related cardiovascular response in frail and non-frail senile patients. These results suggested that remimazolam tosylate is an optimal anesthesia inducer for all elderly patients. Clinical Trial Registration: https://www.chictr.org.cn, identifier ChiCTR2200055709.

Effect of different doses of epidural dexmedetomidine on reducing visceral traction reaction for cesarean section: a double-blind randomized controlled trial

PURPOSE

This study aimed to evaluate the effect of different doses of epidural dexmedetomidine on reducing visceral traction reaction for cesarean section under epidural anesthesia.

METHODS

Nulliparas were randomly allocated to receive epidural ropivacaine alone (group R) or in combination with dexmedetomidine 0.5 μg/kg (group RD0.5), 0.75 μg/kg (group RD0.75), and 1 μg/kg (group RD1) with 46 nulliparas in each group. The primary outcome was intraoperative visceral traction reaction (graded from 0 to 3, with 0 and 3, respectively, regarded as 'no discomfort in stomach or perineum; no nausea, vomiting or intestinal tympanites' and 'serious visceral pain, nausea and vomiting, intestinal tympanites').

RESULTS

Visceral traction reaction was significantly alleviated in group RD0.5, RD0.75, and RD1, respectively, compared to group R while it was comparable among RD groups. Increased Ramsay Sedation Scale and lower incidence of shivering were found in RD groups compared to group R (p < 0.001). None of the primipara has experienced Ramsay Sedation Scale above 4. Higher incidence of thirst was found in group RD0.75 and RD1 compared to group R and RD0.5 (p < 0.001). The Apgar scores at 1 and 5 min of the neonates, onset time to T6 sensory block, maximum sensory block level, the incidence of hypotension, bradycardia and nausea or vomiting were comparable among groups.

CONCLUSION

It is suggested that 0.5 μg/kg epidural dexmedetomidine can be used as adjuvant to epidural ropivacaine during cesarean section, because of its alleviating visceral traction reaction, moderate sedating, and reducing shivering without thirst increase.

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].

Intrathecal Dexmedetomidine Combined With Ropivacaine in Cesarean Section: A Prospective Randomized Double-Blind Controlled Study

Objective

This study aimed to find the best dose of dexmedetomidine in spinal anesthesia for cesarean section.

Methods

120 American Society of Anesthesiologists (ASA) Class I and II parturients undergoing elective cesarean delivery under spinal anesthesia were randomly allocated into four groups treated with intrathecal ropivacaine (12 mg) alone (Group R) or in combination with dexmedetomidine 5 μg (Group RD1), 7.5 μg (Group RD2) and 10 μg (Group RD3). Characteristics of spinal anesthesia, hemodynamic changes, adverse effects, stress reactions and neonatal outcomes were recorded in the four groups.

Results

Patients in Group RD1, RD2, and RD3 had significantly longer sustained sensory and motor block time than patients in Group R. All four groups had comparable onset times of sensory and motor block. The time for the level of sensory block to lower to S1 was longer in Group RD1 (411.07 ± 106.66 min), Group RD2 (397.03 ± 125.39 min) and Group RD3 (468.63 ± 116.43 min) than in Group R (273.60 ± 88.34 min) (p < 0.001). The time to recover from motor block to a Bromage score of IV was longer in Group RD1 (353.60.07 ± 137.28 min), Group RD2 (350.57 ± 118.01 min) and Group RD3 (404.67 ± 112.83 min) than in Group R (232.70 ± 93.29) (p < 0.01). The incidence of chills was significantly lower in the Group RD1, RD2, and RD3 than in the Group R (p < 0.001). There was no significant difference in the incidence of adverse effects such as hypotension, bradycardia, nausea, vomiting, hypoxemia and pruritus in the four groups (p > 0.05). There was no statistically significant visceral traction response or fentanyl use in the four groups (p > 0.05). Phenylephrine dosing was significantly higher in Group RD2 and RD3 than in Group R (p < 0.05), and there was no significant difference in phenylephrine dosing between Group RD1 and Group R (p > 0.05). There were no statistical differences in postnatal Apgar scores (1 min, 5 min after birth) (p > 0.05). The postoperative concentrations of β-endorphin (β-EP), cortisol (Cor) and tumor necrosis factor-α (TNF-α) in the Group RD1, RD2, and RD3 were lower than that in Group R (p < 0.05).

Conclusion

Intrathecal 5μg of dexmedetomidine as an adjuvant to ropivacaine relieved intraoperative chills, did not increase intraoperative and postoperative adverse effects, did not increase the amount of intraoperative vasoconstrictor used, and reduced intraoperative stress reactions as well as prolonged the duration of maternal sensory and motor block, so this dose is appropriate for cesarean section.

Clinical Trial Registration

[www.chictr.org.cn/], identifier [ChiCTR2200056052].

Neuraxial labor analgesia: Initiation techniques

The ideal technique for labor analgesia would have a quick onset, predictable quality, and adjustable depth and duration. Moreover, it would be easy to perform and have minimal maternal and fetal side effects. A catheter-based neuraxial approach encompasses these desirable characteristics and includes the epidural, combined spinal epidural, dural puncture epidural, and intrathecal catheter techniques. In this review, we outline the unique technical considerations, analgesic characteristics, and side effect profiles for each technique that can ultimately impact the maternal-fetal dyad. The selection of neuraxial analgesia techniques should consider the patient and team's goals and expectations, the clinical context, and the institutional culture. Labor analgesic techniques that initiate with an intentional dural puncture component have a faster onset, greater bilateral and sacral spread, and lower rates of epidural catheter failure. Further elucidation of the mechanisms, benefits, and risks of each neuraxial initiation technique will continue to benefit patients and care providers.

Impact of Ultrasound-Guided Deep Serratus Anterior Plane Block Combined With Dexmedetomidine as an Adjuvant to Ropivacaine Inpatient Quality of Recovery Scores Undergoing Modified Radical Mastectomy: A Randomized Controlled Trial

Background

Breast cancer has overtaken lung cancer as the most commonly diagnosed malignancy and is the leading cause of cancer-related death in women. Surgery is the only possible cure for breast cancer, and the incidence of acute postoperative pain (APP) is high in breast surgery. Previous reports suggested that ultrasound-guided deep serratus anterior plane block (dSAPB) provided effective blockade to relieve pain after modified radical mastectomy for breast cancer. In fact, despite the long-acting local anesthetic agents used, the patient’s pain cannot completely be eliminated due to the short duration of anesthesia. Dexmedetomidine as an adjunct to local anesthetics can prolong peripheral nerve block duration. However, no study has investigated the role of dSAPB with dexmedetomidine in the quality of recovery scores undergoing modified radical mastectomy. Thus, this study was conducted aiming at this aspect.

Material and Methods

This single-center, double-blind, randomized clinical trial was conducted at Bethune International Peace Hospital. A total of 88 participants of elective modified radical mastectomy were enrolled from May and November 2021. Ultrasound-guided dSAPB combined with 30 ml of 0.375% ropivacaine or 30 ml of 0.375% ropivacaine with dexmedetomidine (1 μg/kg) was administrated before anesthesia at the fourth to fifth ribs of the axillary midline. The primary outcome was quality of recovery, measured 24 h postoperatively using the QoR-15. Secondary outcomes were the Visual Analogue Scale (VAS) scores at rest and movement at 1, 6, 12, 24, and 48 h after surgery, 48 h sufentanil consumption postoperatively, the incidence of postoperative nausea and vomiting (PONV), length of post-anesthesia care unit (PACU) stay, dizziness, delirium, SAPB-related adverse events, and patient’s satisfaction with pain management.

Results

Among the 88 participants, 8 did not meet the inclusion criteria; the other 80 were randomized to receive dSAPB combined with ropivacaine (Group R, N=40) and dSAPB combined with ropivacaine plus DEX (Group RD, N=40), of which a total of 7 (4 in Group R and 3 in Group RD) were excluded due to protocol deviation. Eventually,73 participants (36 in Group R and 37 in Group RD) were included for final analysis, with age (SD, years, 54.08[6.28] vs. 54.62[7.44], p=0.740), body mass index (BMI) (SD, 27.96[1.67] vs. 27.57[2.38], p=0.428), and median preoperative global QoR-15 score (interquartile range (IQR), 127[123.25–131] vs. 126[121–130], p=0.662). The median postoperative global QoR-15 score (IQR, 107[103–112] vs. 109.5[107–114], p=0.016), VAS score at rest at 12th hour (IQR, 1[1–2] vs. 1[1–2], p=0.033), VAS score in movement at 12th hour (IQR, 2[1–3] vs. 2[1–3], p=0.014) and at 24th hour (IQR, 3[2–3] vs. 3[2–3], p=0.040), and median sufentanil rescues consumption (IQR, 14[12–17 vs. 14[12–15], p=0.022] of Group RD were significantly lower than those of the Group R. Patient satisfaction score (SD, 8.28[0.70] vs. 8.62[0.59], p=0.024) of Group RD were significantly higher than those of the Group R.

Conclusion

The ultrasound-guided dSAPB combined with dexmedetomidine plus ropivacaine may improve the QoR-15 in patients undergoing modified radical mastectomy and indicates that it may be a useful intervention to aid recovery following breast cancer surgery. Furthermore, participants in the ropivacaine with DEX group met the superior pain relief in the early postoperative period, reduced postoperative cumulative opioid consumption, increased patient satisfaction, and no increase in the incidence of complications.

ED50 and ED95 of propofol combined with different doses of esketamine for children undergoing upper gastrointestinal endoscopy: A prospective dose-finding study using up-and-down sequential allocation method

WHAT IS KNOWN AND OBJECTIVE

Propofol and esketamine are routine anaesthetics used in sedation or general anaesthesia for paediatric procedures. Coadministration could reduce the dose of either propofol or esketamine required and lower the incidence of drug-related adverse events. We designed a four-arm randomized controlled trial in children undergoing diagnostic upper gastrointestinal endoscopy to investigate the dose of propofol with different doses of esketamine inducing appropriate depth of anaesthesia in 50% patients (median effective dose, ED₅₀ ).

METHODS

After getting the approval of the research ethics committee and informed consent, 92 paediatric patients planning for upper gastrointestinal endoscopy were divided into four groups randomly: esketamine 0, 0.25, 0.5 and 1 mg/kg groups (n = 23/group). Propofol doses followed the Dixon and Massey up-and-down method with different starting and interval doses between groups. During the first attempt of endoscope insertion, if patients' reactions prevented the insertion, it would be considered as a failure. The awakening time, total propofol doses, as well as the perioperative and post-procedure adverse events were evaluated and recorded for each patient.

RESULTS AND DISCUSSION

The ED₅₀ (median, 95% confidence interval) of propofol was significantly greater in esketamine 0 and 0.25 mg/kg groups in comparison with the esketamine 0.5 and 1 mg/kg groups (4.1 [3.3-4.9]; 3.1 [2.5-3.8] mg/kg vs. 1.8 [1.1-2.4]; 0.8 [0.2-1.3] mg/kg, respectively, p < .05). The total doses of propofol in esketamine 0.5 and 1 mg/kg groups were statistically lower than these in esketamine 0 and 0.25 mg/kg group (p < .01). The mean blood pressure was lower in the esketamine 0 mg/kg group than that in 1 mg/kg group after administration and during the procedure (p < .01). The esketamine 1 mg/kg group showed a higher incidence of vomiting and visual disturbances than the other three groups (p < .001).

WHAT IS NEW AND CONCLUSION

In children who accomplished diagnostic paediatric upper gastrointestinal endoscopy under deep sedation/anaesthesia, the total dosage of propofol needed was reduced significantly in esketamine 0.5 and 1 mg/kg groups with a corresponding reduce in propofol-related hemodynamic changes. However, a higher incidence of esketamine-related adverse effects was found in esketamine 1 mg/kg group.

The Median Effective Concentration (EC50) of Epidural Ropivacaine With Different Doses of Oxycodone During Limb Surgery in Elderly Patients

Background

Oxycodone can be used both intravenously and epidurally in elderly patients because of its strong analgesic effect and more slight respiratory inhibition compared with other opioids at the same effect. In this study, we determined the median effective concentration (EC₅₀) of epidural ropivacaine required for great saphenous vein surgery in elderly patients in order to describe its pharmacodynamic interaction with oxycodone.

Methods

One hundred forty-one elderly patients scheduled for high ligation and stripping of the great saphenous vein surgery were allocated into three groups in a randomized, double-blinded manner as follows: Q2.5 group (2.5 mg oxycodone), Q5.0 group (5.0 mg oxycodone), and C group (normal saline). Anesthesia, was achieved with epidural ropivacaine and oxycodone. The EC₅₀ of ropivacaine for surgery with different doses of oxycodone was adjusted by using an up-and-down sequential methods with an adjacent concentration gradient at a factor of 0.9 to inhibit analgesia. Anesthesia associated adverse events and recovery, characteristics were also recorded.

Results

The EC₅₀ of ropivacaine for the great saphenous vein surgery in elderly patients was 0.399% (95% CI, 0.371–0.430%) in the Q2.5 group, 0.396% (95% CI, 0.355–0.441%) in the Q5.0 group, and 0.487% (95% CI, 0.510–0.465%) in the C group, respectively (P < 0.05). Specially, the EC₅₀ of ropivacaine in the Q2.5 and Q5.0 groups was lower than that in the C group (P < 0.01), But the difference between the Q2.5 group and the Q5.0 group was not significant (P > 0.05). There was no significant difference in the Bromage score from the motor block examination, heart rate (HR) or mean arterial pressure (MAP) at each observation time point after epidural administration among the three groups (P > 0.05). No serious adverse reactions occurred in any of the three groups.

Conclusion

Oxycodone combined with ropivacaine epidural anesthesia can reduce the EC₅₀ of ropivacaine required for elderly patients undergoing the great saphenous vein surgery. There was no significant difference in anesthesia associated adverse events among the three groups. The recommended dose of oxycodone is 2.5 mg.

Recent Advances in the Clinical Value and Potential of Dexmedetomidine

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has sedative, anxiolytic, analgesic, sympatholytic, and opioid-sparing properties and induces a unique sedative response which shows an easy transition from sleep to wakefulness, thus allowing a patient to be cooperative and communicative when stimulated. Recent studies indicate several emerging clinical applications via different routes. We review recent data on dexmedetomidine studies, particularly exploring the varying routes of administration, experimental implications, clinical effects, and comparative advantages over other drugs. A search was conducted on the PubMed and Web of Science libraries for recent studies using different combinations of the words “dexmedetomidine”, “route of administration”, and pharmacological effect. The current routes, pharmacological effects, and application categories of dexmedetomidine are presented. It functions by stimulating pre- and post-synaptic α2-adrenoreceptors within the central nervous system, leading to hyperpolarization of noradrenergic neurons, induction of an inhibitory feedback loop, and reduction of norepinephrine secretion, causing a sympatholytic effect, in addition to its anti-inflammation, sleep induction, bowel recovery, and sore throat reduction effects. Compared with similar α2-adrenoceptor agonists, dexmedetomidine has both pharmacodynamics advantage of a significantly greater α2:α1-adrenoceptor affinity ratio and a pharmacokinetic advantage of having a significantly shorter elimination half-life. In its clinical application, dexmedetomidine has been reported to present a significant number of benefits including safe sedation for various surgical interventions, improvement of intraoperative and postoperative analgesia, sedation for compromised airways without respiratory depression, nephroprotection and stability of hypotensive hemodynamics, reduction of postoperative nausea and vomiting and postoperative shivering incidence, and decrease of intraoperative blood loss. Although the clinical application of dexmedetomidine is promising, it is still limited and further research is required to enhance understanding of its pharmacological properties, patient selection, dosage, and adverse effects.

Comparing the minimum local anesthetic dose of ropivacaine in real-time ultrasound-guided spinal anesthesia and traditional landmark-guided spinal anesthesia: a randomized controlled trial of knee surgery patients

Background

Through previous studies and clinical practice, we have found that real-time ultrasound-guided (UG) spinal anesthesia (SA) and traditional landmark-guided (LG) SA each require a different minimum local anesthetic dose (MLAD) of ropivacaine. For this study, we used Dixon’s up-and-down sequential method to analyze and compare the MLAD of different ropivacaine concentrations required for the UG and LG SA methods.

Methods

A total of 120 patients undergoing knee surgery were consecutively recruited and randomly divided into four groups (30 patients per group). These groups were categorized as follows: Group I: high ropivacaine ultrasound-guided (HRUG), Group II: low ropivacaine ultrasound-guided (LRUG), Group III: high ropivacaine landmark-guided (HRLG), and Group IV: low ropivacaine landmark-guided (LRLG). SA was established by a bolus administration of up-and-down doses of 0.75% or 0.5% plain ropivacaine. Initial doses of 16, 18, 12, and 14 mg were administered to groups I–IV, and after that, increased or decreased by 1.5 mg according to dose effectiveness. Upon identifying the intervertebral puncture level, a lumbar X-ray was performed with metal markers, and actual radiographic findings were identified and compared to the initial markings.

Results

For UG groups, the MLAD in the LRUG group was significantly higher than in the HRUG group [20.192 mg (95% CI, 19.256–21.174) versus 17.176 mg (95% CI, 16.276–18.124), respectively; P<0.001]. For LG groups, the MLAD in the LRLG group was significantly higher than in the HLRG group [14.478 mg (95% CI, 13.364–15.500) versus 13.201 mg (95% CI, 11.959–14.571), respectively; P=0.047]. When comparing both high ropivacaine groups (HRGs: I/III) to the low ropivacaine groups (LRGs: II/IV), we found that both UG subgroups (I/II) had a significantly higher MLAD than LG subgroups (III/IV) (P<0.001). US identified L4–5 in up to 90% of cases. Comparatively, palpation was successful in only 33.3% of patients. The rates of cephalad localization by US and palpation were 6.67% vs. 66.67%, respectively (P=0.002).

Conclusions

We found a higher MLAD of ropivacaine was required for UG SA at the L4–5 level due to the method providing a more accurate (less cephalad) localization than traditional LG SA.

Trial Registration

Chinese Clinical Trial Registry ChiCTR2000033158.

Optimum dose of spinal ropivacaine with or without single intravenous bolus of S-ketamine during elective cesarean delivery: a randomized, double-blind, sequential dose-finding study

Background

Maternal hypotension after spinal anaesthesia occurs at a high rate during caesarean delivery and can lead to adverse maternal or foetal outcomes. The aim of this study was to determine the optimal dose of spinal ropivacaine for caesarean section with or without intravenous single bolus of S-ketamine and to observe the rates of hypotension associated with both methods.

Methods

Eighty women undergoing elective caesarean delivery were randomly allocated into either a ropivacaine only or ropivacaine with intravenous S-ketamine group. If the upper sensory level of the patient reached T6 and the visual analogue scale (VAS) scores remained below 3 points before delivery, the next patient had a 1/9th chance of receiving a lower dose or an 8/9th chance of receiving the same dose as the previous patient. If the patient had VAS scores of more than 2 points or needed an extra epidural rescue bolus before delivery, a higher dose was used for the next patient. The primary outcome was the successful use of spinal ropivacaine to maintain patient VAS score of < 3 points before delivery and the incidence of post-spinal hypotension in both groups. Secondary outcomes included the rates of hypotension-related symptoms and interventions, upper sensory level of anaesthesia, level of sedation, neonatal outcomes, Edinburgh Postnatal Depression Scale scores at admission and discharge, and post-operative analgesic effect. The 90% effective dose (ED90) and 95% confidence interval (95% CI) were estimated by isotonic regression.

Results

The estimated ED90 of ropivacaine was 11.8 mg (95% CI: 11.7–12.7) with and 14.7 mg (95% CI: 14.6–16.0) without intravenous S-ketamine, using biased coin up-down sequential dose-finding method. The rates of hypotension and associated symptoms were significantly lower in S-ketamine group than in the ropivacaine only group.

Conclusions

A spinal dose of ropivacaine 12 mg with a single intravenous 0.15 mg/kg bolus dose of S-ketamine may significantly reduce the risk of hypotension and induce sedation before delivery. This method may be used with appropriate caution for women undergoing elective caesarean delivery and at a high risk of hypotension or experiencing extreme nervousness.

Trial registration

http://www.chictr.org.cn (ChiCTR2000040375; 28/11/2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04229-y.

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.

Intrathecal dexmedetomidine improves epidural labor analgesia effects: a randomized controlled trial

OBJECTIVE

α2‑agonists and opioids have been used as intrathecal adjuvants to local anesthetics for several years, but the effect of intrathecal dexmedetomidine (Dex) or sufentanil combined with epidural ropivacaine in labor analgesia is not fully understood.

METHODS

A total of 108 parturient women receiving combined spinal-epidural labor analgesia were randomly divided into three groups. Group C received l mL saline (0.9%) intrathecally, Group D received 5 µg Dex intrathecally, and Group S received 5 µg sufentanil intrathecally. All parturient women then received 0.1% epidural ropivacaine and 0.2 µg/mL sufentanil for patient-controlled epidural analgesia with standard settings. The visual analog scale score, onset time, duration of intrathecal injection, local anesthetic requirements, and side effects were recorded.

RESULTS

The labor analgesia effects in Groups D and S were better than those in Group C. Groups D and S displayed significantly shorter onset times, longer durations of intrathecal injection, and reduced local anesthetic requirements compared with Group C. The incidence of shivering and pruritus in Group D was lower than that in Group S.

CONCLUSION

Intrathecal administration of 5 µg Dex could improve epidural labor analgesia effects.This randomized controlled clinical trial was registered with the Chinese Clinical Registry Center (ChiCTR-1800014943, http://www.chictr.org.cn/).

Evaluation of ropivacaine combined with dexmedetomidine versus ropivacaine alone for epidural anesthesia: A meta-analysis

BACKGROUND

Ropivacaine is considered the most commonly used for epidural anesthesia. We compared the efficiency and safety of ropivacaine alone (R group) and ropivacaine combined with dexmedetomidine (RD group).

METHOD

PubMed, the Cochrane Library, Google Scholar, Ovid Medline, the Web of Science, Scopus, Embase, and ScienceDirect were searched. We considered sensory and motor block, duration of anesthesia, time to rescue, hemodynamics, and adverse effects as the primary endpoints.

RESULTS

Eleven randomized controlled trials were included with 337 patients in the R group and 336 patients in the RD group. The RD group had a shorter time to onset of sensory (mean difference [MD]: 3.97 [1.90-6.04] minutes; P = .0002) and motor (MD: 2.43 [0.70-4.16] minutes; P = .006) block and a longer duration of anesthesia (MD: -164.17 [-294.43 to -33.91]; P = .01) than the R group. Comparison of the time to rescue between the groups showed no significant difference (MD: -119.01[-254.47-16.46] minutes; P = 0.09). The R group showed more stable hemodynamics than the RD group in heart rate and arterial pressure at 10 minutes. The R group had a lower incidence of bradycardia and a higher incidence of shivering than the RD group.

CONCLUSION

RD may be a more suitable choice for epidural anesthesia with better anesthetic outcomes than R alone. However, the safety of the combination must be carefully assessed.