Intrathecal sufentanil decreases the median effective dose (ED50) of intrathecal hyperbaric ropivacaine for caesarean delivery

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.

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.

Sufentanil for Spinal Analgesia during Cesarean Section Delivery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To investigate the effect of sufentanil for spinal analgesia during cesarean section.

METHOD

Eligible papers were systematically retrieved from PubMed, Embase, Ovid, and ScienceDirect. Two researchers independently extracted primary and secondary endpoints to compute relative risk and mean difference by using the random-effects model or the fixed-effects model, as appropriate. Publication bias was quantified and assessed using funnel plot and Egger's test.

RESULT

A total of 8 publications with 503 pregnant women were included in this study for meta-analysis. Subarachnoid administration of sufentanil did not significantly reduce the onset time of sensory block and motor block. Nonetheless, subarachnoid administration of sufentanil significantly increased the incidence of postoperative skin pruritus (RR = 5.25, 95%CI: 1.90, 14.49, P < 0.001).

CONCLUSION

Subarachnoid administration of sufentanil has no significant difference in the combined effect value of shortening the onset time of sensory block and motor block, prolonging the onset time of local anesthesia and the incidence of some adverse reactions (such as postoperative nausea, vomiting, hypotension, and tremors). However, the incidence of skin pruritus was significantly increased, and the difference was statistically significant. Because of this, the drug still needs to be used with caution in combination with the actual situation in clinical use.

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.

Effects of intrathecal opioids on cesarean section: a systematic review and Bayesian network meta-analysis of randomized controlled trials

PURPOSE

We aimed to compare the beneficial and harmful effects of opioids used as adjuncts to local anesthetics in patients undergoing cesarean section under spinal anesthesia.

METHODS

We searched electronic databases and ClinicalTrials.gov from their inception until March, 2021 without language restrictions. The primary outcome was the complete analgesia duration (Time to VAS > 0). Data were synthesized using the Bayesian random-effects model. Evidence confidence was evaluated using the Confidence In Network Meta-Analysis.

RESULTS

We identified 66 placebo-controlled randomized controlled trials (RCTs) comprising 4400 patients undergoing elective cesarean section. Compared with the placebo, intrathecal opioids (fentanyl, sufentanil, and morphine) significantly prolonged the analgesia duration by 96, 96, and 190 min, respectively (mean difference). Despite morphine ranking first, opioid efficacy was similar; the results were inconsistent with respect to other analgesic outcomes. Except for diamorphine, all opioids were associated with significant increases in the pruritus incidence. Sufentanil and morphine were associated with increases in the respiratory depression incidence.

CONCLUSIONS

We confirmed that intrathecal opioids benefit postoperative analgesia. Although morphine seems to be the most appropriate agent, some results were inconsistent, and the evidence confidence was often moderate or low, especially for adverse outcomes. Well-designed RCTs with an evidence-based approach are imperative for determining the most appropriate opioid for cesarean sections.

Addition of low-dose sufentanil to ropivacaine for reducing shivering and visceral traction pain during cesarean section

Objective

To investigate the efficacy of low-dose sufentanil for preventing shivering and visceral traction pain during cesarean section under spinal anesthesia.

Methods

This was a prospective, randomized, controlled study. A total of 112 full-term parturients who underwent elective caesarean delivery were randomly divided into two groups. Group R received 0.75% isobaric ropivacaine intrathecally and group RS received 0.75% isobaric ropivacaine plus 5 µg sufentanil intrathecally.

Results

There were no significant differences in the maximum sensory block time, motor block time, duration of the surgery, and heart rate, mean arterial pressure, and blood oxygen saturation before and 1, 5, and 10 minutes after spinal anesthesia, and at the end of the surgery between the two groups. Shivering was significantly more common in group R (n = 30) than in group RS (n = 8). The incidence of visceral traction pain in group R (46.43%) was significantly higher than that in group RS (14.29%). There was no significant difference in the newborns’ Apgar scores between the groups.

Conclusion

Adding low-dose sufentanil to ropivacaine can significantly reduce the incidence of shivering and visceral traction pain after spinal anesthesia.

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

STUDY OBJECTIVE

Adjuvant dexmedetomidine can be used to reduce the required concentration of ropivacaine for labor epidural analgesia. However, the potency of dexmedetomidine has not been fully studied. The purpose of this study was to determine the median effective concentration (EC₅₀) of ropivacaine with adjuvant dexmedetomidine.

DESIGN

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

SETTING

Academic medical center specializing in the care of women and children.

PATIENTS

One hundred and fifty healthy, term parturients requesting labor epidural analgesia were randomly assigned to 1 of 5 different concentrations of dexmedetomidine: 0 μg/ml, 0.3 μg/ml, 0.4 μg/ml, 0.5 μg/ml, or 0.6 μg/ml.

INTERVENTIONS

The study solution for the first patient in each group included the randomly assigned concentration of dexmedetomidine in 0.1% ropivacaine. Subsequent patients in each randomization group received the assigned concentration of dexmedetomidine in a new concentration of ropivacaine as determined by the up-down allocation methodology. Effective analgesia was defined as pain on the visual analogue scale of<3 at30 min after administration of local anesthetic. The up-down sequential allocation method and probit regression were used to calculate the EC₅₀ of epidural ropivacaine.

MEASUREMENTS

The primary outcome was pain 30 min after administration of local anesthetic via epidural catheter. Exploratory outcomes included side effects, neonatal outcomes, and obstetric outcomes.

MAIN RESULTS

The EC₅₀ values for ropivacaine in dexmedetomidine 0.4 μg/ml, 0.5 μg/ml, and 0.6 μg/ml (0.044% [95% CI 0.036% to 0.045%], 0.035% [95% CI 0.031% to 0.041%], and 0.039% [95% CI 0.034% to 0.045%], respectively) were lower compared to ropivacaine in dexmedetomidine 0 μg/ml and 0.3 μg/ml (0.086% [95% CI 0.081% to 0.092%], and, 0.069% [95% CI 0.056% to 0.076%], respectively). Differences between EC₅₀ values for ropivacaine in dexmedetomidine 0.4 μg/ml, 0.5 μg/ml, and 0.6 μg/ml were not statistically significant. Results of our exploratory analyses did not reveal differences in side effects, neonatal outcomes, or obstetric outcomes.

CONCLUSIONS

In this study, the lowest concentration of dexmedetomidine in ropivacaine with the greatest clinical effect was 0.4 μg/ml, which is important because there may be no additional analgesic benefit of dexmedetomidine greater than 0.4 μg/ml.

The Median Effective Dose of One Intravenous Bolus of Oxycodone for Postoperative Analgesia After Myomectomy and Hysterectomy With Local Ropivacaine Wound Infiltration: An Up-Down Dose-Finding Study

BACKGROUND

Oxycodone has been shown to be an effective analgesic for early postoperative analgesia, especially for abdominal operations associated with severe visceral pain. However, the dose needed varies depending on the operation and application of multimodal analgesia, such as local ropivacaine wound infiltration. Therefore, we conducted this study to estimate the median effective dose (ED50) of oxycodone that provides analgesia for hysterectomy and myomectomy with local ropivacaine wound infiltration.

METHODS

In this dose-finding study, the ED50 of oxycodone for postoperative analgesia was estimated separately for laparoscopic hysterectomy, transabdominal hysterectomy, laparoscopic myomectomy, and transabdominal myomectomy. We used the sequential allocation designed by Dixon. Trials were conducted simultaneously in the 4 surgical type groups. A predefined dose of oxycodone was injected 30 minutes before the end of the operation with an initial dose of 0.1 mg/kg. A series of trials were performed following the rule of a relative 10% increase in dose after inadequate analgesia and a relative 10% decrease in dose after adequate analgesia. The study was conducted until the collection of 7 crossover points was achieved. Local ropivacaine wound infiltration was administered during abdominal stitching. The mean blood pressure (MBP) and heart rate (HR) were analyzed to assess the hemodynamic changes associated with oxycodone administration.

RESULTS

A total of 113 patients were included in the estimation of ED50: 28 each in the laparoscopic hysterectomy group and transabdominal myomectomy group, 27 in the transabdominal hysterectomy group, and 30 in the laparoscopic myomectomy group. The estimated oxycodone ED50 (95% confidence interval [CI]) after laparoscopic hysterectomy, transabdominal hysterectomy, laparoscopic myomectomy, and transabdominal myomectomy was 0.060 mg/kg (0.053-0.068), 0.079 mg/kg (0.072-0.086), 0.060 mg/kg (0.051-0.071), and 0.092 mg/kg (0.086-0.098), respectively, for postoperative analgesia with local ropivacaine wound infiltration. The ED50 of oxycodone was different between laparoscopic surgeries and transabdominal surgeries (P < .001). The MBP and HR before and after oxycodone injection were different, regardless of surgical type.

CONCLUSIONS

The oxycodone ED50 for postoperative analgesia was lower for laparoscopic hysterectomy (0.060 mg/kg) and laparoscopic myomectomy (0.060 mg/kg) than for transabdominal hysterectomy (0.079 mg/kg) and transabdominal myomectomy (0.092 mg/kg) when combined with local ropivacaine wound infiltration. A single intravenous injection of oxycodone is associated with an acceptable decrease in MBP and HR within a short time.

Effect of intrathecal lipophilic opioids on the incidence of shivering in women undergoing cesarean delivery after spinal anesthesia: a systematic review and bayesian network meta- analysis of randomized controlled trials

Background

Shivering is a common side effect in women having cesarean delivery (CD) under spinal anesthesia, which can be bothersome to the patient, and it can also interfere with perioperative monitoring. In several studies, the intrathecal (IT) addition of a lipophilic opioid to local anesthetics has been shown to decrease the incidence of shivering.

Objective

We performed this network meta-analysis to evaluate the effects of intrathecal lipophilic opioids in preventing the incidence of shivering in patients undergoing CD.

Methods

This review was planned according to the PRISMA for Network Meta-Analysis (PRISMA-NMA) guidelines. An English literature search of multiple electronic databases was conducted. We included randomized controlled trials (RCTs) that reported on the incidence of shivering, with study groups receiving either IT fentanyl, sufentanil, or meperidine in women undergoing CD under spinal anesthesia. Quality of the studies was assessed using the modified Oxford scoring system. Using random-effects modeling, dichotomous data were extracted and summarized using odds ratio (OR) with a 95% credible interval (CrI). Statistical analysis was conducted using R studio version 1.0.153 - Inc.

Results

Twenty-one studies consisting of 1433 patients (Control group: 590 patients in twenty-one studies; Fentanyl group:199 patients in seven studies; Sufentanil group: 156 patients in five studies; Meperidine group: 488 patients in ten studies) met the inclusion criteria for this systematic review investigating the effect of intrathecal lipophilic opioids in preventing the incidence of shivering in women undergoing cesarean delivery under spinal anesthesia. Methodological validity scores ranged from 3 to 7. The Bayesian mixed network estimate showed the incidence of shivering was significantly lower with IT fentanyl (pooled odds ratio (OR): 0.13; 95% credible interval (CrI): 0.04 to 0.35; P = 0.0004) and IT meperidine (OR: 0.12; 95% CrI: 0.05 to 0.29; P < 0.00001), but not with IT sufentanil (OR: 0.37; 95% CrI: 0.11 to 1.22; P = 0.23). The IT fentanyl group had a significantly lower incidence of intraoperative discomfort [Risk Ratio (RR): 0.19; 95% CI: 0.10–0.35; P < 0.00001], the IT sufentanil group had a significantly higher incidence of pruritus (RR: 6.18; 95% CI: 1.18–32.46; P = 0.03) The IT meperidine group had a significantly lower incidence of intraoperative discomfort (2.7% vs. 13.6%; RR: 0.22; 95% CI: 0.09–0.55; P = 0.001), but there was a significant increase in nausea and vomiting (IT meperidine group vs. Control group: 42.7% vs. 19.4%; RR: 2.56; 95% CI: 1.14–5.75; P = 0.02). Meta-regression analysis based on the opioid dose and quality of the study did not impact the final inference of our result.

Conclusion

IT fentanyl significantly decreased the incidence of shivering in women undergoing CD under spinal anesthesia without increasing maternal adverse events, confirming that routine use in this patient population is a good choice. IT sufentanil did not decrease the incidence of shivering. IT meperidine decreased the incidence and severity of shivering, but its use was also associated with significant nausea and vomiting.

Effect of Different Doses of Intrathecal Dexmedetomidine as an Adjuvant Combined With Hyperbaric Ropivacaine in Patients Undergoing Cesarean Section

Objective

In this study, we aim to investigate the effect of different doses of dexmedetomidine as an adjuvant to hyperbaric ropivacaine in spinal anesthesia for cesarean section.

Methods

Seventy-five parturients with American Society of Anesthesiologists (ASA) I or II were anesthetized with intrathecal ropivacaine (12.5 mg) alone (R group) or in combination with dexmedetomidine 3 μg (RD3 group) and 5 μg (RD5 group) to undergo a cesarean section. The anesthetic parameters, postoperative analgesia, stress responses and neonates outcomes were monitored.

Results

The onset time of sensory block to T10, T4, and peak level in the RD3 group and RD5 group were significantly shorter than those in the R group (p < 0.05). The time of the level of sensory block to descend two segments and to T10 in the RD3 group(57.28 ± 16.65 min, 3.87 ± 1.60 h) and RD5 group (71.92 ± 10.10 min, 3.99 ± 1.06 h) were longer than that in the R group (40.64 ± 12.06 min, 1.98 ± 1.01 h) (p < 0.05). The median time of motor blockade to both legs score 3 on the Bromage scale (B3B3) in the RD3 group and RD5 group was shorter than that in the R group (p < 0.001). The time of motor blockade recovery to both legs score 0 on the Bromage scale (B0B0) in the RD5 group (3.6 h) was longer than that in the R group (2 h) or RD3 group (2.2 h) (p < 0.001). Visceral traction response and abdominal muscle relaxation during the operation in the RD3 group and the RD5 group were better than that in the R group. The Visual Analogue Score (VAS) in the 12 h after the operation in the RD3 group (3.30 ± 1.17) and RD5 group (2.80 ± 0.87) was smaller than that in the R group (3.80 ± 1.47) (p < 0.05). The incidence of shivering in the RD3 group and RD5 group was significantly lower than that in the R group (p < 0.05). The postoperative concentrations of c-reactive protein (CRP), interleukin-6 (IL-6) and cortisol in the RD3 and RD5 groups were lower than that in the R group (p < 0.05).

Conclusion

3 µg intrathecal dexmedetomidine as an adjuvant to ropivacaine improved intraoperative somato-visceral sensory block characteristics and postoperative analgesia, alleviated shivering in parturients, and did not prolong the time of motor block or produce any side effects, which makes this dose appropriate for cesarean delivery.

Cinical Trial Registration

ChiCTR, identifier ChiCTR1800014454. Registered 15 January 2018, http://www.chictr.org.cn/edit.aspx?pid=24613&htm=4

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

STUDY OBJECTIVE

Studies have showed that intrathecal dexmedetomidine as supplements to local anesthetics can improve the quality of the spinal anesthesia and reduce the local anesthetic requirement of spinal anesthesia for cesarean section. However, the magnitude of this effect has not been fully quantified. Therefore, we conducted the present study to investigate the ED₅₀ of intrathecal hyperbaric ropivacaine with or without dexmedetomidine for cesarean section in healthy parturients. ED₅₀ values obtained were compared to estimate the effect of intrathecal dexmedetomidine versus placebo on ropivacaine requirement.

DESIGN

Single-blinded, prospective, randomized study.

SETTING

Department of Anesthesia, Women's Hospital, Zhejiang University School of Medicine.

PATIENTS

Sixty healthy parturients under elective cesarean section with combined spinal-epidural anesthesia were randomized into Group C (intrathecal ropivacaine alone) and Group D (intrathecal ropivacaine + 5 μg dexmedetomidine).

INTERVENTIONS

The dose of intrathecal ropivacaine for the first parturient in both groups was 11 mg. An increment or decrement of 0.5 mg intrathecal ropivacaine was made for the subsequent parturient based on the effective or ineffective response of the previous parturient. Effective dose was defined as a bilateral T6 or above sensory block level was achieved within 15 min after induce of spinal anesthesia and no additional epidural anesthetics was required during surgery. The Dixon and Massay sequential method and Probit regression were applied to calculate the ED₅₀ of intrathecal ropivacaine in both groups.

MEASUREMENTS

Characteristics of spinal anesthesia and side effects were recorded.

MAIN RESULTS

The ED₅₀ of hyperbaric ropivacaine calculated by Dixon and Massay formula was 11.4 mg (95% CI, 11.1-11.7 mg) in Group C, and 9.4 mg (95% CI, 9.0-9.7 mg) in Group D (P < 0.05). While using the Probit regression, the ED₅₀ of intrathecal hyperbaric ropivacaine was 11.1 mg (95% CI, 10.7-11.6 mg) in Group C, and 9.1 mg (95% CI, 8.6-9.5 mg) in Group D. Shivering was less observed in Group D than in Group C (P < 0.05). There was no significant difference in the onset time of sensory block or motor block, the incidence of hypotension, bradycardia, nausea and vomiting, sedation and pruritus between the two groups.

CONCLUSION

Under the conditions of the present study, intrathecal dexmedetomidine (5 μg) reduced the ED₅₀ of intrathecal hyperbaric ropivacaine by approximately 18% for cesarean section in healthy parturients under combined spinal-epidural anesthesia.

Neuraxial adjuvants for prevention of perioperative shivering during cesarean section: A network meta-analysis following the PRISMA guidelines

BACKGROUND

Perioperative shivering is clinically common during cesarean sections under neuraxial anesthesia, and several neuraxial adjuvants are reported to have preventive effects on it. However, the results of current studies are controversial and the effects of these neuraxial adjuvants remain unclear.

AIM

To evaluate the effects of neuraxial adjuvants on perioperative shivering during cesarean sections, thus providing an optimal choice for clinical application.

METHODS

A systematic review and network meta-analysis were conducted following the PRISMA (Preferred Reported Items for Systematic Review and Meta-analysis) guidelines. Analyses were performed using Review Manager 5.3 and Stata 14.0. We searched PubMed, EMBASE, Web of Science, and Cochrane Central databases for eligible clinical trials assessing the effects of neuraxial adjuvants on perioperative shivering and other adverse events during cesarean sections. Perioperative shivering was defined as the primary endpoint, and nausea, vomiting, pruritus, hypotension, and bradycardia were the secondary outcomes.

RESULTS

Twenty-six studies using 9 neuraxial adjuvants for obstetric anesthesia during caesarean sections were included. The results showed that, compared with placebo, pethidine, fentanyl, dexmedetomidine, and sufentanil significantly reduced the incidence of perioperative shivering. Among the four neuraxial adjuvants, pethidine was the most effective one for shivering prevention (OR = 0.15, 95%CI: 0.07-0.35, surface under the cumulative ranking curve 83.9), but with a high incidence of nausea (OR = 3.15, 95%CI: 1.04-9.57) and vomiting (OR = 3.71, 95%CI: 1.81-7.58). The efficacy of fentanyl for shivering prevention was slightly inferior to pethidine (OR = 0.20, 95%CI: 0.09-0.43), however, it significantly decreased the incidence of nausea (OR = 0.34, 95%CI: 0.15-0.79) and vomiting (OR = 0.25, 95%CI: 0.11-0.56). In addition, compared with sufentanil, fentanyl showed no impact on haemodynamic stability and the incidence of pruritus.

CONCLUSION

Pethidine, fentanyl, dexmedetomidine, and sufentanil appear to be effective for preventing perioperative shivering in puerperae undergoing cesarean sections. Considering the risk-benefit profiles of the included neuraxial adjuvants, fentanyl is probably the optimal choice.

The effect of intrathecal dexmedetomidine on the dose requirement of hyperbaric bupivacaine in spinal anaesthesia for caesarean section: a prospective, double-blinded, randomized study

Background

Studies have shown that dexmedetomidine (Dex) can prolong the duration of analgesia when added to local anaesthetic as an adjuvant in a central or peripheral nerve block. We hypothesized that intrathecal Dex can reduce the ED95 of spinal hyperbaric bupivacaine. Therefore, we conducted this prospective, double-blinded, randomized study to verify our hypothesis.

Methods

Ninety patients were allocated into the Dexmedetomidine group (received bupivacaine + 5 mcg dexmedetomidine) and the Control group (received bupivacaine + the same volume of saline) using a double-blinded and randomized method. The first patient in each group received 5 mg of IT hyperbaric bupivacaine, and the next dose for the following patient was determined by the probability of successful anaesthesia of the previous neighbouring dose. An improved up-down sequence allocated method combined with probit analysis was used to determine the ED95 of intrathecal hyperbaric bupivacaine for the two groups.

Results

The ED95 and 95% confidence intervals (95% CI) of IT hyperbaric bupivacaine of the Dex group and Control group were 8.4 mg (95% CI, 6.5~ 13.8 mg) and 12.1 mg (95% CI, 8.3~ 312.8 mg), respectively. The duration of sensory block was longer in the Dex group than in the Control group (110.3 ± 35.3 vs 67.5 ± 26.2). The duration of analgesia was also longer in the Dex group than in the Control group (224.9 ± 45.4 vs 155.1 ± 31.6). The consumption of postoperative rescued sufentanil was significantly higher in the Control group than in the Dex group.

Conclusion

Intrathecal 5 mcg dexmedetomidine potentiated hyperbaric bupivacaine antinociception by 31% in spinal anaesthesia for patients undergoing caesarean section.

Trial registration

We registered this study in a Chinese Clinical Trial Registry (ChiCTR) centre on Nov 1st 2016 and received the registration number: ChiCTR-IPR-16009699.

ED50 of intrathecal ropivacaine for cesarean section under prophylactic infusion of phenylephrine: A consort study

BACKGROUND

Studies have reported that prophylactic continuous infusion of phenylephrine during spinal anesthesia for cesarean section can decrease the spread of local anesthetics. We investigated the ED50 of intrathecal hyperbaric ropivacaine in parturient women undergoing cesarean section under prophylactic infusion of phenylephrine.

METHODS

Sixty parturient women were allocated into 2 groups in this prospective study. Group P received 0.5 mL kg h of phenylephrine (5 mg/50 mL) at the start of intrathecal injection, and Group C (control group) received the same volume of saline. The dose of intrathecal ropivacaine for each subject was decided through up-down allocation method. The initial dose was set as 7.5 mg. Successful anesthesia was defined as the level of T6 or above achieved within 15 minutes after intrathecal injection and no additional epidural drug or venous analgesia to complete operation. The Massey formula was applied to calculate the ED50 of intrathecal ropivacaine in both groups.

RESULTS

The ED50 of hyperbaric ropivacaine determined by up-and-down method was 7.2 mg (95% confidence interval (CI), 6.8-7.6 mg) in the Group P, and 6.8 mg (95% CI, 6.4-7.2 mg) in the Group C, there was significant difference between the 2 groups (P < .5). The ED50 of intrathecal ropivacaine increases compared with Group C when phenylephrine is prophylactic infused to prevent spinal induced hypotension in cesarean section.

CONCLUSION

The ED50 of intrathecal hyperbaric ropivacaine is 7.2 mg when phenylephrine is prophylactic infused to prevent spinal induced hypotension in cesarean section, and more ropivacaine demands on spinal anesthesia for cesarean section (www.chictr.org.cn, registration number: ChiCTR-RIC-17011650).

Body height and the spread of spinal anaesthesia for caesarean section: a prospective controlled trial

BACKGROUND

No conclusive evidence exists on the effect of patient height on the spread of spinal anaesthesia. Our aim was to measure the ED₅₀ and ED₉₅ values of intrathecal ropivacaine in taller and shorter patients, and thus investigate the hypothesis that the spinal dose requirement in shorter patients is lower than that in taller patients undergoing caesarean section.

METHODS

In this study, 270 pregnant women were assigned to the taller (Group T) or shorter group (Group S) based on their heights. Subjects in both groups were further randomly assigned to one of nine subgroups based on the dosage of intrathecal isobaric ropivacaine to be administered (7, 8, 9, 10, 11, 12, 13, 14 or 15 mg respectively).

RESULTS

The ED₅₀ and ED₉₅ values of ropivacaine were 9.24 mg and 13.36 mg in Group S, and 10.11 mg and 14.63 mg in Group T, with no inter-group difference (P = 0.886). There was a significant inter-group difference in the incidence of hypotension and the changes in mean arterial pressure after spinal anaesthesia using 15 mg ropivacaine. The dose of ephedrine administered in Group S was higher than that in Group T when 15 mg ropivacaine was administered (P = 0.031).

CONCLUSION

The taller and shorter patients did not respond differently to modest intrathecal doses of ropivacaine. However, a larger dose of ropivacaine was associated with an increased incidence of hypotension in shorter patients compared to that in taller patients.

Intrathecal magnesium sulfate does not reduce the ED50 of intrathecal hyperbaric bupivacaine for cesarean delivery in healthy parturients: a prospective, double blinded, randomized dose-response trial using the sequential allocation method

Background

Addition of intrathecal magnesium sulfate to local anesthetics has been reported to potentiate spinal anesthesia and prolong analgesia in parturients. The current study was to determine whether intrathecal magnesium sulfate would reduce the dose of hyperbaric bupivacaine in spinal anesthesia with bupivacaine and sufentanil for cesarean delivery.

Methods

Sixty healthy parturients undergoing scheduled cesarean delivery were randomly assigned to receive spinal anesthesia with 0.5% hyperbaric bupivacaine and 5 μg sufentanil with either 0.9% sodium chloride (Control group) or 50% magnesium sulfate (50 mg) (Magnesium group). Effective anesthesia was defined as a bilateral T₅ sensory block level achieved within 10 min of intrathecal drug administration and no additional epidural anesthetic was required during surgery. Characteristic of spinal anesthesia and the incidence of side effects were observed. The ED₅₀ for both groups was calculated using the Dixon and Massey formula.

Results

There was no significant difference in the ED₅₀ of bupivacaine between the Magnesium group and the Control group (4.9 mg vs 4.7 mg) (P = 0.53). The duration of spinal anesthesia (183 min vs 148 min, P < 0.001) was longer, the consumption of fentanyl during the first 24 h postoperatively (343 μg vs 550 μg, P < 0.001) was lower in the Magnesium group than that in the Control group.

Conclusions

Intrathecal magnesium sulfate (50 mg) did not reduce the dose requirement of intrathecal bupivacaine, but can extend the duration of spinal anesthesia with no obvious additional side effects.

Trial registration

This study was registered with Chinese Clinical Trial Registry (ChiCTR) on 15 Jul. 2014 and was given a trial ID number ChiCTR-TRC-14004954.

The Dose-response of Intrathecal Ropivacaine Co-administered with Sufentanil for Cesarean Delivery under Combined Spinal-epidural Anesthesia in Patients with Scarred Uterus

Background:

Spinal anesthesia is considered as a reasonable anesthetic option in lower abdominal and lower limb surgery. This study was to determine the dose-response of intrathecal ropivacaine in patients with scarred uterus undergoing cesarean delivery under combined spinal-epidural anesthesia.

Methods:

Seventy-five patients with scarred uterus undergoing elective cesarean delivery under combined spinal-epidural anesthesia were enrolled in this randomized, double-blinded, dose-ranging study. Patients received 6, 8, 10, 12, or 14 mg intrathecal hyperbaric ropivacaine with 5 μg sufentanil. Successful spinal anesthesia was defined as a T₄ sensory level achieved with no need for epidural supplementation. The 50% effective dose (ED₅₀) and 95% effective dose (ED₉₅) were calculated with a logistic regression model.

Results:

ED₅₀ and ED₉₅ of intrathecal hyperbaric ropivacaine for patients with scarred uterus undergoing cesarean delivery under combined spinal-epidural anesthesia (CSEA) were 8.28 mg (95% confidence interval [CI]: 2.28–9.83 mg) and 12.24 mg (95% CI: 10.53–21.88 mg), respectively.

Conclusion:

When a CSEA technique is to use in patients with scarred uterus for an elective cesarean delivery, the ED₅₀ and ED₉₅ of intrathecal hyperbaric ropivacaine along with 5 μg sufentanil were 8.28 mg and 12.24 mg, respectively. In addition, this local anesthetic is unsuitable for emergent cesarean delivery, but it has advantages for ambulatory patients.

ED 50 and ED 95 of intrathecal bupivacaine coadministered with sufentanil for cesarean delivery under combined spinal-epidural in severely preeclamptic patients

Background:

Spinal anesthesia was considered as a reasonable anesthetic option in severe preeclampsia when cesarean delivery is indicated, and there is no indwelling epidural catheter or contraindication to spinal anesthesia. However, the ideal dose of intrathecal bupivacaine has not been quantified for cesarean delivery for severe preeclamptic patients. This study aimed to determine the ED₅₀ and ED₉₅ of intrathecal bupivacaine for severely preeclamptic patients undergoing elective cesarean delivery.

Methods:

Two hundred severely preeclamptic patients are undergoing elective cesarean delivery under combined spinal-epidural anesthesia enrolled in this randomized, double-blinded, dose-ranging study. Patients received 4 mg, 6 mg, 8 mg, or 10 mg intrathecal hyperbaric bupivacaine with 2.5 μg sufentanil. Successful spinal anesthesia was defined as a T6 sensory level achieved within 10 minutes after intrathecal drug administration and/or no epidural supplement was required during the cesarean section. The ED₅₀ and ED₉₅ were calculated with a logistic regression model.

Results:

ED₅₀ and ED₉₅ of intrathecal bupivacaine for successful spinal anesthesia were 5.67 mg (95% confidence interval [CI]: 5.20–6.10 mg) and 8.82 mg (95% CI: 8.14–9.87 mg) respectively. The incidence of hypotension in Group 8 mg and Group 10 mg was higher than that in Group 4 mg and Group 6 mg (P < 0.05). The sensory block was significantly different among groups 10 minutes after intrathecal injection (P < 0.05). The use of lidocaine in Group 4 mg was higher than that in other groups (P < 0.05). The use of phenylephrine in Group 8 mg and Group 10 mg was higher than that in the other two groups (P < 0.05). The lowest systolic blood pressure before the infant delivery of Group 8 mg and Group 10 mg was lower than the other two groups (P < 0.05). The satisfaction of muscle relaxation in Group 4 mg was lower than other groups (P < 0.05). There was no significant difference in patients’ satisfaction and the newborns’ Apgar score and the blood gas analysis of umbilical artery serum (P > 0.05).

Conclusion:

Our study showed that the ED₅₀ and ED₉₅ of intrathecal bupivacaine for severely preeclamptic patients undergoing elective cesarean delivery were 5.67 mg and 8.82 mg, respectively. In addition, decreasing the dose of intrathecal bupivacaine could reduce the incidence of maternal hypotension.

Sparing effects of sufentanil on epidural ropivacaine in elderly patients undergoing transurethral resection of prostate surgery

PURPOSE

This study examined the sparing effect of sufentanil on the median effective concentration (EC₅₀) of epidural ropivacaine in elderly patients undergoing elective transurethral resection of prostate (TURP).

MATERIALS AND METHODS

This was a prospective randomized double-blind dose-response study. Fifty eight elderly patients with American Society of Anesthesiologists physical status I-II who were scheduled for TURP surgery under epidural anesthesia were randomly allocated to a group receiving 15 mL of ropivacaine (group R) or a group receiving ropivacaine plus 5 μg of sufentanil (group RS). The concentration of ropivacaine was determined by a Dixon's up-and-down sequential allocation. The first participant received 0.3% of ropivacaine in both groups and subsequent concentrations were determined by the response of the previous patient in the same group. The EC₅₀ of epidural ropivacaine was analyzed using the Dixon and Massey method.

RESULTS

The EC₅₀ of ropivacaine during TURP surgery was 0.186% (95% confidence interval, 0.173-0.200%) in group R, and 0.136% (95% confidence interval, 0.127-0.144%) in group RS (p<0.01). No differences in Bromage scale of motor block examination and the onset time of sensory block were observed.

CONCLUSION

Administration of 5 μg of epidural sufentanil caused a 37% reduction in the EC₅₀ of epidural ropivacaine in elderly patients who underwent TURP surgery. Thus, sufentanil addition during surgery of TURP can decrease the dose of ropivacaine anesthesia required.

A randomized clinical study comparing spinal anesthesia with isobaric levobupivacaine with fentanyl and hyperbaric bupivacaine with fentanyl in elective cesarean sections

BACKGROUND

To date, racemic bupivacaine is the most popular local anesthetic for spinal anesthesia in parturients undergoing elective cesarean delivery. With the introduction of levobupivacaine as pure S (-) enantiomer of bupivacaine which offers advantages of lower cardiotoxicity and neurotoxicity and shorter motor block duration, its use has widely increased in India. However, very few studies have been conducted about its efficacy in obstetric anesthesia. Thus, this study was undertaken to compare the sensorial, motor block levels, and side-effects of equal doses of hyperbaric bupivacaine and levobupivacaine with intrathecal fentanyl addition in elective cesarean cases.

MATERIALS AND METHODS

After approval of College Ethical Committee, 30 parturient with American Society of Anesthesiologists I-II undergoing elective cesarean section were enrolled for study with their informed consent. They were randomly divided equally to either Group BF receiving 10 mg (2 ml) hyperbaric bupivacaine and 25 mcg (0.5 ml) fentanyl, or Group LF receiving 10 mg (2 ml) isobaric levobupivacaine and 25 mcg (0.5 ml) fentanyl. Sensory and motor block characteristics of the groups were assessed with pinprick, cold swab, and Bromage scale; observed hemodynamic changes and side-effects were recorded. Effects on the neonate were observed by APGAR score at 1 and 5 min and umbilical cord blood gas analysis.

RESULTS

Hemodynamic parameters like mean arterial pressure of Group BF were found to be lower. Group BF exhibited maximum motor block level whereas in Group LF, max sensorial block level and postoperative visual analog scale scores were higher. Umbilical blood gas pCO2 was slightly higher, and pO2 was marginally lower in Group BF. Onset of motor block time, time to max motor block, time to T10 sensorial block, reversal of two dermatome, the first analgesic need were similar in both groups.

CONCLUSION

Intrathecal isobaric levobupivacaine-fentanyl combination is a good alternative to hyperbaric bupivacaine-fentanyl combination in cesarean surgery as it is less effective in motor block, it maintains hemodynamic stability at higher sensorial block levels.

Comparison of dexmedetomidine and propofol for conscious sedation in awake craniotomy: a prospective, double-blind, randomized, and controlled clinical trial

BACKGROUND

It has been reported that dexmedetomidine (DEX) can be used for conscious sedation in awake craniotomy, but few data exist to compare DEX versus propofol (PRO).

OBJECTIVE

To compare the efficacy and safety of DEX versus PRO for conscious sedation in awake craniotomy.

METHODS

Thirty patients of American Society of Anesthesiologists grade I-II scheduled for awake craniotomy, were randomized into 2 groups each containing 15 subjects. Group D received DEX and group P received PRO. Two minutes after tracheal intubation (T1), PRO (target plasma concentration) was titrated down to 1 to 4 µg/mL in group P. In group D, PRO was discontinued and DEX was administered 1.0 µg/kg followed by a maintenance dose of 0.2 to 0.7 µg/kg/h. The surgeon preset the anticipated awake point-in-time (T0) preoperatively. Ten minutes before T0 (T3), DEX was titrated down to 0.2 µg/kg/h in group D, PRO was discontinued and normal saline (placebo) 5 mL/h was infused in group P. Arousal time, quality of revival and adverse events during the awake period, degree of satisfaction from surgeons and patients were recorded.

RESULTS

Arousal time was significantly shorter in group D than in group P (P < .001). The quality of revival during the awake period in group D was similar to that of group P (P = .68). The degree of satisfaction of surgeons was significantly higher in group D than in group P (P < .001), but no difference was found between the 2 groups with respect to patient satisfaction (P = .80). There was no difference between the 2 groups in the incidence of adverse events during the awake period (P > .05).

CONCLUSIONS

Either DEX or PRO can be effectively and safely used for conscious sedation in awake craniotomy. Comparing the two, DEX produced a shorter arousal time and a higher degree of surgeon satisfaction.

The Effect of Body Mass Index on Spinal Anaesthesia for Total Knee Replacement Arthroplasty: A Dose-response Study

The aim of this study was to compare the duration of spinal anaesthesia in obese and non-obese subjects. We also quantified the effect of body mass index (BMI) on spinal anaesthesia by comparing the median effective dose (ED50) of intrathecal hyperbaric bupivacaine required in the two cohorts. One hundred and eight patients undergoing elective total knee replacement arthroplasty under combined spinal-epidural anaesthesia were enrolled as a non-obese group (BMI <27.5 kg/m2) or obese (O) group (BMI ≤27.5 kg/m2). Each group was further subdivided by bupivacaine doses of 6, 7, 8, 9, 10 or 11 mg, respectively. Anaesthesia was deemed successful if a bilateral T12 sensory block occurred within 15 minutes of intrathecal drug administration and epidural supplementation was not required. The ED50 for successful anaesthesia and that for successful block of tourniquet pain were determined separately by probit regression analysis. Although the analgesic duration was prolonged with higher doses of bupivacaine in group O, the ED50 for successful anaesthesia did not differ between groups. However, the incidence of tourniquet pain was lower in group O and the ED50 for block of tourniquet pain was less in group O. This study suggests that bupivacaine dose reduction is not necessary, but analgesic duration may be prolonged in patients with higher BMI. These patients require careful consideration of spinal anaesthetic dose to minimise the risk of unnecessary prolongation of anaesthesia.