Comparison of hypotensive properties of dexmedetomidine versus clonidine for induced hypotension during functional endoscopic sinus surgery: A randomised, double-blind interventional study

Dexmedetomidine and surgical field visibility in nasal surgery: A systematic review and meta-analysis

INTRODUCTION

Nasal and sinus surgery, especially using endoscopy, relies upon adequate haemostasis to be safe and effective. Often other haemostatic methods, such as cautery are not viable, and other methods must be employed. This study examines the effectiveness of dexmedetomidine in controlled hypotension and for surgical field visibility in endoscopic sinus surgery and other nasal surgeries.

REVIEW METHODS

A literature search was conducted in PubMed, Scopus, CINAHL and Central for randomised controlled trials using dexmedetomidine for controlled hypotension in adult patients undergoing endoscopic sinus surgery or other nasal surgery. Meta-analysis of mean differences and single means were performed.

RESULTS

Of 935 identified studies, 31 met the inclusion criteria. A statistically significant difference in Fromme-Boezaart surgical field visibility scores was found comparing dexmedetomidine to placebo (p < 0.00001) and propofol (p < 0.0001), but not other agents. A significant difference in intraoperative blood loss volume was found compared with placebo (51.5mL, p < 0.00001) and propofol (13.6mL, p < 0.0001), but not other agents.

CONCLUSION

Dexmedetomidine demonstrated significantly improved surgical field visibility and blood loss volume compared with placebo and propofol, but not other agents. Dexmedetomidine is viable and useful for controlled hypotension in nasal surgery. Choice of controlled hypotension agent should follow patient and procedure-specific considerations.

Does preoperative administration of hypotensive agents affect the quality of the surgical field during endoscopic sinus surgery? A triple-blind randomized controlled trial

PURPOSE

Endoscopic sinus surgery (ESS) is a surgical procedure widely used in the treatment of various sinonasal conditions. Excessive bleeding during ESS leads to potentially major complications. The primary aim of this trial was to explore any different effects of bisoprolol and nifedipine on the intraoperative surgical field. In addition, the correlations regarding surgical field state, total blood loss (TBL), mean arterial pressure (MAP), and heart rate (HR) were also examined.

METHODS

A prospective, triple-blinded, randomized, placebo-controlled trial was conducted, including 72 patients between 18 and 65 years of age who underwent ESS. As an indicator of the worst state of the intraoperative surgical field, the Boezaart scale score was used, as evaluated by two surgeons. Appropriate statistical analysis was conducted to explore score comparisons across groups and correlations between vital signs, bleeding, and the operative field state.

RESULTS

No statistically significant difference was found among different intervention groups regarding the worst state of the surgical field (p = 0.367 > 0.05). The Boezaart scale score was positively correlated with TBL (rxy = 0.619, p = 0.000 < 0.001) and MAP (rxy = 0.259, p = 0.028 < 0.05). Furthermore, MAP was positively correlated with HR (rs = 0.254, p = 0.32 < 0.05).

CONCLUSION

Our study demonstrates that preoperative administration of bisoprolol and nifedipine does not affect the worst state of the operative field. However, vital signs seem to either directly or indirectly affect bleeding and operative field state, and agents affecting them are worth exploring further.

Effect of dexmedetomidine on postoperative nausea and vomiting in patients under general anaesthesia: an updated meta-analysis of randomised controlled trials

OBJECTIVES

To explore the effect of dexmedetomidine (DEX) on postoperative nausea and vomiting (PONV) in adult patients after general anaesthesia.

DESIGN

Systematic review and meta-analysis.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials (RCTs) comparing the efficacy of DEX with placebo or a single drug on PONV in adult patients after general anaesthesia.

DATA SOURCES

We searched the PubMed, the Web of Science, the Cochrane Library and Embase (1 January 2000 to 30 June 2022) to select the relevant RCTs.

DATA ANALYSIS

All the relevant data were analysed by using RevMan V.5.4. Heterogeneity was tested for each outcome, and random-effect or fixed-effect models was selected according to the level of heterogeneity. The primary outcome was the incidence of PONV. The secondary outcomes were the incidence of bradycardia, perioperative opioid consumption, extubation time and the length of hospitalisation.

RESULTS

A total of 18 trials involving 2018 patients were included in this meta-analysis. Notably, 15 updated studies were not involved in the previous meta-analysis. The incidence of PONV in DEX group was lower than that in the control group (OR=0.49, 95% CI: 0.36 to 0.67) and the perioperative opioid consumption in DEX group was also decreased significantly (standard mean difference (SMD)=-1.04, 95% CI: -1.53 to -0.54). Moreover, the length of hospitalisation (SMD=-2.29, 95% CI: -4.31 to -0.28) and the extubation time (SMD=-0.75, 95% CI: -1.26 to -0.25) in DEX group were shorter. Whereas, more number of patients receiving DEX might increase the occurrence of bradycardia (OR=1.60, 95% CI: 1.13 to 2.27).

CONCLUSIONS

DEX could decrease the occurrence of PONV in adult patients under general anaesthesia and promote the recovery after surgery. However, DEX might increase the occurrence of bradycardia.

PROSPERO REGISTRATION NUMBER

CRD 42022341548.

Assessment of haemodynamic response to tracheal intubation and prone positioning following clonidine and enalaprilat in lumbar spine surgeries: A double blind randomised controlled trial

Background and Aim

This study evaluates the effectiveness of long-acting antihypertensive drugs (clonidine and enalaprilat) in blunting the intubation response. Also, the study seeks to determine how effectively clonidine and enalaprilat can maintain stable haemodynamics during a change in position.

Methods

After ethical committee approval and trial registration, a double-blinded, randomised controlled trial was conducted with 71 consenting patients scheduled for elective spine surgery in a prone position under general anaesthesia. Group C received clonidine 2 μg/kg, and Group E received enalaprilat 1.25 mg diluted in normal saline as an intravenous infusion given over 10 min before induction of anaesthesia. The changes in heart rate (HR) and blood pressure (BP) in response to the infusion of the study drugs, induction, tracheal intubation and change in position were recorded. P value <0.05 was considered significant. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 25.

Results

Clonidine infusion caused a significant fall in heart rate post-infusion and post-induction with propofol (p value <0.05). Both clonidine and enalaprilat caused a significant fall in mean arterial pressure (MAP) post-infusion and post-induction (p value <0.05). Clonidine effectively blunted the intubation response with no increase in HR and MAP following intubation. Enalaprilat caused a significant rise in HR in response to intubation. On proning, there was a significant fall in MAP in both groups.

Conclusion

Clonidine is effective in blunting the intubation response. Preoperative infusion of clonidine and enalaprilat causes hypotension during a change of position.

The Role of miRNAs in Dexmedetomidine's Neuroprotective Effects against Brain Disorders

There are limited neuroprotective strategies for various central nervous system conditions in which fast and sustained management is essential. Neuroprotection-based therapeutics have become an intensively researched topic in the neuroscience field, with multiple novel promising agents, from natural products to mesenchymal stem cells, homing peptides, and nanoparticles-mediated agents, all aiming to significantly provide neuroprotection in experimental and clinical studies. Dexmedetomidine (DEX), an α2 agonist commonly used as an anesthetic adjuvant for sedation and as an opioid-sparing medication, stands out in this context due to its well-established neuroprotective effects. Emerging evidence from preclinical and clinical studies suggested that DEX could be used to protect against cerebral ischemia, traumatic brain injury (TBI), spinal cord injury, neurodegenerative diseases, and postoperative cognitive disorders. MicroRNAs (miRNAs) regulate gene expression at a post-transcriptional level, inhibiting the translation of mRNA into functional proteins. In vivo and in vitro studies deciphered brain-related miRNAs and dysregulated miRNA profiles after several brain disorders, including TBI, ischemic stroke, Alzheimer’s disease, and multiple sclerosis, providing emerging new perspectives in neuroprotective therapy by modulating these miRNAs. Experimental studies revealed that some of the neuroprotective effects of DEX are mediated by various miRNAs, counteracting multiple mechanisms in several disease models, such as lipopolysaccharides induced neuroinflammation, β-amyloid induced dysfunction, brain ischemic-reperfusion injury, and anesthesia-induced neurotoxicity models. This review aims to outline the neuroprotective mechanisms of DEX in brain disorders by modulating miRNAs. We address the neuroprotective effects of DEX by targeting miRNAs in modulating ischemic brain injury, ameliorating the neurotoxicity of anesthetics, reducing postoperative cognitive dysfunction, and improving the effects of neurodegenerative diseases.

Adequacy of Anesthesia and Pupillometry for Endoscopic Sinus Surgery

Inadequate intraoperative analgesia causes the deterioration of the condition of the surgical field (CSF) as a result of hemodynamic instability. Analgesia monitors are used to guide remifentanil) infusion to optimize intraoperative analgesia. The main aim of the current randomized controlled trial was to investigate the potential advantages of intraoperative analgesia monitoring using surgical Pleth index (SPI)- or pupillometry (PRD)-guided remifentanil administration for managing the volume of total intraoperative blood loss (TEIBL), CSF, and length of operation (LOP) in comparison with the standard practice in patients undergoing endoscopic sinus surgery (ESS). The 89 patients in our study were grouped as follows: 30 patients were assigned to the general analgesia (GA) group, 31 patients were assigned to the SPI group, and 28 patients were assigned to the PRD group. The speed of remifentanil infusion was accelerated by 50% when SPI, PRD, or BSS were increased by >15 points, >5%, or >2, respectively, in adjacent groups until their normalization. The SPI group showed significantly lower TEIBL in comparison to the GA group (165.2 ± 100.2 vs. 283.3 ± 193.5 mL; p < 0.05) and a higher mean arterial pressure (MAP; 73.9 ± 8 vs. 69.2 ± 6.8 mmHg; p < 0.05). In the PRD group, a shorter LOP compared with the GA group was observed (63.1 ± 26.7 min vs. 82.6 ± 33.1 min; p < 0.05). It was noted that the PRD group had a lower total remifentanil consumption than the SPI group (1.3 ± 1.4 vs. 1.8 ± 0.9 mg; p < 0.05). In ASA I-III patients undergoing ESS, intraoperative monitoring based on state entropy and SPI values can optimize the CSF and reduce TEIBL, whereas monitoring based on state entropy and PRD measurements can optimize the cost effectiveness of anesthetic drugs and the use of the operation room.