The efficacy and safety of intrathecal dexmedetomidine for parturients undergoing cesarean section: a double-blind randomized controlled trial

Clinical Use of Adrenergic Receptor Ligands in Acute Care Settings

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

The effect of adding dexmedetomidine or dexamethasone to bupivacaine-fentanyl mixture in spinal anesthesia for cesarean section

Background and Aims

Many strategies are available to prevent spinal-induced hypotension in cesarean section, especially the use of a low dose of spinal anesthesia combined with adjuvants. This study investigated the effect of adding either dexmedetomidine or dexamethasone to the intrathecal bupivacaine-fentanyl mixture on the postoperative analgesia duration, after elective cesarean section.

Material and Methods

This prospective, randomized, double-blind study was conducted on 90 full-term parturients undergoing elective cesarean section, who were randomly distributed into three groups. They all received spinal anesthesia with the bupivacaine-fentanyl mixture (2.5 ml), in addition to 0.5 ml normal saline (control group), 5 μg dexmedetomidine dissolved in 0.5 ml normal saline (dexmedetomidine group), or 2 mg dexamethasone (dexamethasone group). The time to the first request of morphine rescue analgesia was recorded, in addition to the total dose of morphine consumed in the first 24 h after surgery, the postoperative numerical rating score (NRS), and maternal and fetal outcomes.

Results

As compared to the control group and the dexamethasone group, the use of dexmedetomidine as an additive to the bupivacaine-fentanyl mixture significantly prolonged the time to the first request of rescue analgesia, decreased postoperative morphine consumption, and decreased the pain score 4 and 6 h after surgery. There was an insignificant difference between the control and dexamethasone groups.

Conclusion

The use of dexmedetomidine as an additive to bupivacaine-fentanyl mixture in spinal anesthesia for cesarean section prolonged the postoperative analgesia and decreased the postoperative opioid consumption in comparison to the addition of dexamethasone or normal saline.

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.

A Systematic Review and Meta-analysis of Efficacy and Safety of Dexmedetomidine Combined With Intrathecal Bupivacaine Compared to Placebo

BACKGROUND

 Dexmedetomidine has been approved as a sedative agent in critical patients. It is also frequently used as an adjuvant with local anesthetic in spinal anesthesia. However, its use as an adjuvant has not been approved due to the paucity of data. The present systematic review and meta-analysis were undertaken to synthesize evidence for efficacy and safety when dexmedetomidine is combined with bupivacaine in spinal anesthesia.

METHODS

A literature search was done using PubMed, Google Scholar, Embase, and Cochrane Library. Search results were screened and eligible studies were included to perform a systematic review and meta-analysis using the software 'Review Manager (RevMan) version 5.4.1' using a random effect model. Cochrane's' Risk of Bias tool (RoB2)' was used for quality assessment. Mean and standard deviation was used to calculate the standardized mean difference and its forest plot for efficacy measures. For the adverse event, a number of events were used to determine the risk ratio and its forest plot using RevMan software. Publication bias is visualized using a funnel plot.

RESULTS

 A total of 21 randomized control trials evaluating the efficacy and safety of intrathecal dexmedetomidine were included in the meta-analysis. A total of 1382 participants was included in this meta-analysis. The effect estimates for efficacy parameters, i.e. duration of the sensory block having SMD 2.33; CI, 1.83-2.83, motor block with SMD 1.83, CI 1.21, 2.46, and analgesia SMD 2.81; CI, 2.11-3.51. The risk ratio for adverse effects, i.e. nausea/vomiting, bradycardia, hypotension was not significant whereas it was significant for the incidence of shivering with RR 0.38; CI 0.23-0.97. The overall risk of bias among included studies was either of 'some concern' or 'high risk.'

CONCLUSIONS

 Intrathecal dexmedetomidine when combined with bupivacaine was found to significantly increase the three efficacy parameters, i.e. duration of sensory block, motor block, and analgesia. It also appears to be safe with no increased risk of bradycardia or hypotension. It is also associated with decreased postoperative shivering.

Postoperative recovery: how and when is it assessed: a scoping review

BACKGROUND

There is no consensus about the type of instrument with which to assess postoperative recovery or the time points when assessments are most appropriate. It is also unclear whether instruments measure the four dimensions of postoperative recovery, that is physical, psychological, social, and habitual recovery. This scoping review had three objectives: (1) to identify and describe instruments used in clinical trials to assess postoperative recovery; (2) to determine how, when, and the number of times postoperative recovery was measured; and (3) to explore whether the four dimensions of postoperative recovery are represented in the identified instruments.

METHODS

A literature search was conducted in CINAHL, MEDLINE, and Web of Science. The search terms were related to three search strands: postoperative recovery, instrument, and clinical trials. The limits were English language and publication January 2010 to November 2021. In total, 5015 studies were identified.

RESULTS

A total of 198 studies were included in the results. We identified 20 instruments measuring postoperative recovery. Different versions of Quality of Recovery represented 81.8% of the included instruments. Postoperative recovery was often assessed at one time point (47.2%) and most often on postoperative day 1 (81.5%). Thirteen instruments had items covering all four dimensions of postoperative recovery.

CONCLUSIONS

Assessing recovery is important to evaluate and improve perioperative care. We emphasise the importance of choosing the right instrument for the concept studied and, if postoperative recovery is of interest, of assessing more than once. Ideally, instruments should include all four dimensions to cover the whole recovery process.