Clonidine versus sufentanil as an adjuvant to ropivacaine in patient-controlled epidural labour analgesia: A randomised double-blind trial

A Comparison Between Dexmedetomidine and Clonidine as Adjuvants to Levobupivacaine in Labour Analgesia

Background

The epidural analgesia technique is effective for labor analgesia and combinations of various local anesthetics with lipophilic opioids like fentanyl are used. However, fentanyl can cause an increased incidence of pruritus, urinary retention, nausea, vomiting, giddiness, shivering, and respiratory depression. Dexmedetomidine and clonidine are selective alpha 2 agonists with analgesic properties and have been used via the neuraxial route with local anesthetics for the same without the side effects of fentanyl. Thus, the primary objective was to assess and compare the analgesic efficacy of the two-drug combinations by the visual analog scale (VAS) score.

Methods

Fifty-four primigravida women were randomly allocated in two groups of 27 each and were given an initial bolus of 10 mL of 0.125% levobupivacaine with dexmedetomidine 0.5 ug/kg in Group A and with clonidine 1 μg/kg in Group B. Subsequently, each patient received a background infusion rate of 10 mL/h, a bolus dose of 5 ml, and a lock-out interval of 10 min via a patient-controlled-analgesia (PCA) pump. The blood pressure, heart rate, and severity of pain using VAS were assessed. Durations of the stages of labor, rate of instrumental delivery, and cesarean section, side effects, maternal sedation, and neonatal Apgar scores were also recorded.

Results

VAS scores in both the groups progressively decreased to <3 by 15 min with significant differences at five, 10, 15, and 120 min being lower in group A. Onset of analgesia and time for maximum analgesia was significantly shorter in group A. There was a significant decrease in hemodynamic parameters from baseline in both groups. The fall in heart rate was significantly greater in Group A and at almost all the time intervals after baseline, diastolic blood pressure (DBP) was also lower in group A. Maternal motor blockade scores, the intensity of maternal sedation, the incidence of maternal complications, the duration of the first and second stage of labor, the rate of instrumental delivery and cesarean section, total analgesic dose and PCA bolus requirement, and neonatal Apgar scores did not show a significant difference between the two groups.

Conclusion

Both dexmedetomidine and clonidine provide hemodynamically stable labor with a fall in heart rate and maternal blood pressure in the initial hours. Dexmedetomidine has the advantage of faster onset of analgesia and time for maximum analgesia.

A Systematic Review and Meta-Analysis of Randomized Controlled Trials of Labor Epidural Analgesia Using Moderately High Concentrations of Plain Local Anesthetics versus Low Concentrations of Local Anesthetics with Opioids

Purpose

Compared to low concentrations of local anesthetics with opioids for labor epidural analgesia, very high concentrations of local anesthetics are associated with an increased risk of assisted vaginal delivery. We aimed to investigate if moderately high concentrations of plain local anesthetics are also associated with this risk.

Methods

We searched for published randomized controlled trials that compared moderately high concentrations of plain local anesthetics (>0.1% but ≤0.125% bupivacaine, >0.1% but ≤0.125% levobupivacaine, or >0.17% but ≤0.2% ropivacaine) to low concentrations of local anesthetics (≤0.1% bupivacaine, ≤0.1% levobupivacaine, or ≤0.17% ropivacaine) with opioids for labor analgesia. Meta-analyses were performed to compare the risk of assisted vaginal delivery and other perinatal outcomes between these two groups.

Results

We identified nine randomized controlled trials with a total of 1334 participants. Meta-analysis of these nine trials showed no differences in the risks of assisted vaginal delivery (odds ratio [OR] = 1.18; 95% confidence interval [CI], 0.93–1.49) or Cesarean delivery (OR = 0.96; 95% CI, 0.71–1.29) between the two groups. The incidence of motor block was higher in the group of moderately high concentrations (OR = 4.05; 95% CI, 2.19–7.48), while the incidence of pruritus was lower (OR = 0.07; 95% CI, 0.03–0.16).

Conclusion

This systematic review and meta-analysis suggests that the current evidence is inadequate to support that moderately high concentrations of plain local anesthetics increase the risk of assisted vaginal delivery compared to low concentrations of local anesthetics with opioids.

Effects of a Clonidine Taper on Dexmedetomidine Use and Withdrawal in Adult Critically Ill Patients-A Pilot Study

OBJECTIVES

Prolonged use of dexmedetomidine has become increasingly common due to its favorable sedative and anxiolytic properties. Hypersympathetic withdrawal symptoms have been reported with abrupt discontinuation of prolonged dexmedetomidine infusions. Clonidine has been used to transition patients off dexmedetomidine infusions for ICU sedation. The objective of this study was to compare the occurrence of dexmedetomidine withdrawal symptoms in ICU patients transitioning to a clonidine taper versus those weaned off dexmedetomidine alone after prolonged dexmedetomidine infusion.

DESIGN

This was a single-center, prospective, double cohort observational study conducted from November 2017 to December 2018.

SETTING

Medical-surgical, cardiothoracic, and neurosurgical ICUs in a tertiary care hospital.

PATIENTS

We included adult ICU patients being weaned off dexmedetomidine after receiving continuous infusions for at least 3 days.

INTERVENTIONS

Patients were either weaned off dexmedetomidine alone or with a clonidine taper at the discretion of the providers.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of at least two dexmedetomidine withdrawal symptoms during a single assessment within 24 hours of dexmedetomidine discontinuation. Time on dexmedetomidine after wean initiation and difference in medication cost were also evaluated. Forty-two patients were included in this study: 15 received clonidine (Group C) and 27 weaned off dexmedetomidine alone (Group D). There was no significant difference in the incidence of two or more withdrawal symptoms between groups (73% in Group C vs 59% in Group D; p = 0.51). Patients in Group C spent less time on dexmedetomidine after wean initiation compared with patients in Group D (19 vs 42 hr; p = 0.02). An average cost savings of $1,553.47 per patient who received clonidine was observed. No adverse effects were noted.

CONCLUSIONS

Our study demonstrated that patients receiving clonidine were able to wean off dexmedetomidine more rapidly, with a considerable cost savings and no difference in dexmedetomidine withdrawal symptoms, compared with patients weaned off dexmedetomidine alone. Clonidine may be a safe, effective, and practical option to transition patients off prolonged dexmedetomidine infusions.

Investigation of the Minimum Local Analgesic Concentration of Epidural Sufentanil Combined With Ropivacaine for Labor Analgesia

PURPOSE

Worldwide, there are only few studies focusing on labor analgesia on the MLAC (minimum local analgesic concentration) or EC50 (median effective concentration) of sufentanil and ropivacaine. Therefore, we determine the MLAC or EC50 of sufentanil and ropivacaine for epidural analgesia by using an up-down sequential allocation and survey its adverse effect in a prospective blinded randomized trial.

METHODS

Sixty nulliparous full-term parturients who required labor analgesia were recruited and randomly divided into the sufentanil and ropivacaine groups. The formulation was 25 μg sufentanil combined with 0.1% ropivacaine (added 0.9% normal saline to 75 ml). According to the response of a previous parturient, the dosage of sufentanil was increased or decreased by 5 μg in the sufetanil group; meanwhile, we also administrated an initial concentration of 0.1% ropivacaine combined with 22.5 μg sufentanil (added 0.9% normal saline to 75 ml) in the ropivacaine group. The concentration of ropivacaine was increased or decreased by 0.01% following the response of the previous parturient. The Brownlee up-down sequential allocation was used to estimate the MLAC of epidural ropivacaine and its 95% confidence intervals in labor analgesia.

FINDINGS

There were no significant changes for the two groups, including for age, height weight, active stage, second stage of labor, and gestational weeks (P = 0.769, 0.900, 0.603, 0.441, 0.577, and 0.695, respectively). The VAS scores of the parturient decreased to varying degrees (P < 0.0001) after labor analgesia compared with VAS before labor analgesia, and the most effective analgesia was reached in 60 min. The EC50 dose of epidural ropivacaine combined with 0.3 μg/mL sufentanil was 0.09687%, and the 95% CI was 0.08944%~0.1043%. Five parturients had PONV, and the incidence rate was 16.7%; one parturient had pruritus, so the incidence rate was 3.3%. The EC50 dose of epidural sulfetanil combined with 0.1% ropivacaine was 18.76 μg with a 95% confidence interval of 13.5-24.48 μg. There were no significant differences in the active stage, second stage of labor, and maternal and fetal hemodynamic data between the two groups. Notably, the Apgar scores for 1 min and 5 min were 10 scores for almost all of these patients. There were no significant differences between the two groups for maternal and fetal side effects, which had very low incidence rates.

IMPLICATIONS

The MLAC of epidural sufentanil or ropivacaine could provide satisfactory and safe analgesia for parturients while having a low incidence rate of side effects.

Impact of Ondansetron on Withdrawal Signs, Fentanyl Requirement and Pain Relief in Opioid-addicted Patients under General Anesthesia

BACKGROUND

Serotonin 5-HT3 receptor antagonists such as ondansetron have been investigated to attenuate opioid withdrawal signs in studies.

OBJECTIVE

Therefore, we designed a randomized double-blinded placebo-controlled trial to evaluate this effect on opioid-addicted patients who were admitted to the orthopedic department for surgery due to bone fractures.

METHODS

Male adults who were addicted to opioids, aged 18 to 79 years were enrolled (n=96) and randomized into intravenous doses (4 & 8 mg) of ondansetron (n=32) and placebo (n=32). The vital signs, withdrawal symptoms and the frequency requirement of fentanyl were recorded during anesthesia, and opioid (pethidine) analgesic was received during the recovery period. Outcome parameters were analyzed for reduction of withdrawal symptoms in addicted adults.

RESULTS

We indicated that ondansetron demonstrated significant differences with few vital outcomes including systolic blood pressure (SBP) 20 (SBP3) and 50 min (SBP4) after injection of ondansetron during the period of surgery. Ondansetron could also significantly reduce the frequency requirement of fentanyl at 20 min (dose 3) in general anesthesia. Furthermore, requirement for further administration of opioid analgesic drugs such as pethidine was significantly reduced in the ondansetron groups. Objective opioid withdrawal scale (OOWS) results indicated that few clinical parameters including tremor, hot and cold flushes and anxiety were significantly attenuated in addicted patients who received ondansetron.

CONCLUSION

This study demonstrated supporting evidence for the beneficial treatment of ondansetron for the control of withdrawal symptoms and pain in addicted patients, and more clinical studies are suggested in this regard.