Dexmedetomidine as an additive to local anesthetics compared with intravenous dexmedetomidine in peribulbar block for cataract surgery

The effects of subtenon and intravenous dexmedetomidine on patients undergoing cataract surgery: A comparative randomized controlled double-blind study

Background and Aims

This prospective randomized study designed to evaluate the efficacy of dexmedetomidine either added to LA mixture or administered IV during subtenon block for cataract surgery.

Material and Methods

75 patients, undergoing cataract surgery with subtenon anesthesia, were assigned randomly into three equal groups, Group I received subtenon bupivacaine 0.5% (1 ml) + lidocaine 2% (1 ml) + saline 0.9% (0.5 ml) and IV infusion of normal saline. Group II received subtenon bupivacaine 0.5% (1 ml) + lidocaine 2% (1 ml) + 0.5 μg/kg dexmedetomidine (0.5 ml) and IV infusion of normal saline. Group III received subtenon bupivacaine 0.5% (1 ml) + lidocaine 2% (1 ml) + saline 0.9% (0.5 μl) and IV infusion of 0.5 mg/kg dexmedetomidine over 10 min. before subtenon block. We recorded onset and duration of sensory and motor block, pain during subtenon injection, intraoperative hemodynamics, intraocular pressure, sedation and postoperative pain score.

Results

There was a significant decrease in the onset of action and an increase in the duration of sensory block in Group II. Pain during subtenon injection was significantly less in group III. Sedation Score was higher in Group III, while heart rate showed a significant reduction in the same group. The VAS was significantly decreased in group II. After the end of surgery, the intraocular pressure was significantly decreased in Groups II and III.

Conclusion

Subtenon dexmedetomidine shortens onset time, prolongs sensory block durations and significantly decreases the postoperative pain score with hemodynamic stability, while, IV dexmedetomidine substantially reduces pain during subtenon block and produces intra-operative sedation.

Efficacy of adjuvants in ophthalmic regional anesthesia: A systematic review and network meta-analysis

PURPOSE

This network meta-analysis aims to determine the differences between adjuvants that are used in combination with local anesthetics for ophthalmic regional anesthesia.

DESIGN

Systematic review and network meta-analysis METHODS: A systematic literature search for randomized controlled trials, comparing the impact of adjuvants in ophthalmic regional anesthesia, in Embase, CENTRAL, MEDLINE and Web of Science was performed. Risk of bias was evaluated using the Cochrane risk of bias tool. Frequentist network meta-analysis was performed using a random effects model with saline as the comparator. Primary endpoints were the onset and the duration of sensory block and globe akinesia, as well as the duration of analgesia. Summary measure was the ratio of means (ROM). Secondary endpoints were the rates of side effects and adverse events.

RESULTS

39 trials were identified as eligible for network meta-analysis, including 3046 patients. 17 adjuvants were compared in the most extensive network (onset of globe akinesia). The addition of fentanyl (F), clonidine (C) or dexmedetomidine (D) showed the best overall results. Onset of sensory block: F 0.58 [CI 0.47-0.72], C 0.75 [0.63-0.88], D 0.71 [0.61-0.84], onset of globe akinesia: F 0.71 [0.61-0.82], C 0.70 [0.61-0.82], D 0.81 [0.71-0.92], duration of sensory block: F 1.20 [1.14-1.26], C 1.22 [1.18-1.27], D 1.44 [1.34-1.55], duration of globe akinesia: F 1.38 [1.22-1.57], C 1.45 [1.26-1.67], D 1.41 [1.24-1.59], duration analgesia: F 1.46 [1.33-1.60], C 1.78 [1.63-1.96], D 1.41 [1.28-1.56].

CONCLUSION

The addition of fentanyl, clonidine or dexmedetomidine showed beneficial effects regarding onset and duration of sensory block and globe akinesia.

Comparison between the Effects of Acetaminophen, Dexmedetomidine, and Normal Saline Infusion on Pain Severity after Cataract Surgery

BACKGROUND

Cataract surgery is one of the most common eye surgeries, which is currently performed under topical anesthesia using sedative medications. Dexmedetomidine and acetaminophen are good candidates for analgesia in other circumstances, however, this study aimed to evaluate the effect of dexmedetomidine or acetaminophen infusion and normal saline (NS) alone compared with the control group on the severity of pain in cataract surgery.

MATERIALS AND METHODS

In this parallel randomized controlled clinical trial, the effect of dexmedetomidine or acetaminophen infusion and NS on level of pain, vital signs, recovery status, and surgeon satisfaction during cataract surgery were assessed. One hundred and thirty-five patients between the age of 50-80 years undergoing cataract surgery were recruited on a consecutive basis and randomized into three groups receiving acetaminophen (15 mg/kg), dexmedetomidine (0.5 μgr/kg), and NS. Baseline vital signs, blood pressure, arterial oxygen saturation, respiratory and heart rate at certain time-points including the start of surgery, 5, 10, and 15 min after surgery, after arrival to the recovery room, 20, 40, 60 min after recovery were measured. Pain intensity and drugs side effects were also recorded after surgery.

RESULTS

Level of respiratory depression was higher in patients receiving dexmedetomidine. Heart rate and oxygen saturation percentage had no significant differences in the three groups as well as pain intensity.

CONCLUSIONS

Acetaminophen was as effective as dexmedetomidine with lower side effects and higher surgeons' satisfaction, without any interference with cardiovascular and respiratory parameters. Acetaminophen infusion should be considered as an acceptable analgesic drug for cataract surgery.

Efficacy of adding dexmedetomidine to lidocaine to enhance inferior alveolar nerve block in patients with asymptomatic irreversible pulpitis: double-blind randomized clinical trial

OBJECTIVES

This randomized, double-blind study was to determine whether dexmedetomidine (DEX) helped to improve the inferior alveolar nerve block's (IANB) success in patients with asymptomatic irreversible pulpitis (AIP). We hypothesized that adding DEX to lidocaine enhances the anesthetic effect of lidocaine to a satisfactory level by localizing anesthesia in a safer way.

MATERIALS AND METHODS

Fifty adult volunteers with AIP in a first or second mandibular molar were randomly assigned to two groups to either receive 1.4 ml 2% plain lidocaine or 1.4 ml 2% lidocaine + 0.4 ml (40 μg) DEX, for standard IANB injection. Access cavity preparation initiated 10-15 min postinjection when the patient reported lower lip numbness and had two negative electric pulp tests (EPTs) with 5-min intervals. Heft-Parker visual analog scale (VAS) was used to report pain in three steps: during caries and dentin removal, access cavity preparation, and canal working-length determinations; EPT and VAS were analyzed by Friedman test; and success rates were analyzed by Mann-Whitney and Fisher's exact test using SPSS software version 20.

RESULTS

Successful anesthesia (defined as no or mild pain during any of steps and no need for additional injection) is obtained in 12% of patients in the lidocaine group, while DEX-lidocaine group increased the success rate of IANB to 72% (p-value = 0.0001).

CONCLUSIONS

DEX significantly increases the anesthetic effect of lidocaine in IANB injection in patients with AIP.

CLINICAL RELEVANCE

DEX would be a safe adjunct to lidocaine to increase the success rate in IANB and could be a suitable alternative for conventional vasoconstrictors in sensitive groups.

Effect of adding dexmedetomidine to 0.75% ropivacaine in peribulbar block for vitreoretinal surgery

Background and Aims

Peribulbar anesthesia is suitable for vitreoretinal (VR) surgery. Dexmedetomidine has been used in peribulbar block (PBB) to improve akinesia and analgesia. We aimed to study the efficacy of adding dexmedetomidine to 0.75% Ropivacaine in PBB for VR surgery. The primary outcome was the requirement of block supplementation and secondary outcome was post-operative analgesic requirement.

Material and Methods

100 adult patients undergoing VR surgery were included in this prospective randomized double-blinded controlled study. The composition of the drug used for PBB in the 3 groups was Group R (8 ml of 0.75% Ropivacaine +0.5 ml normal saline (NS)), Group D25 (8 ml of 0.75% Ropivacaine +25μg Dexmedetomidine) and Group D50 (8 ml of 0.75% Ropivacaine +50 μg Dexmedetomidine).

Results

The groups were comparable in terms of patient demographics. The requirement for block supplementation was 16.7% in Group R (5/30), 12.5% in Group D25 (4/32) and 8.8% in group D50 (3/34) (P = 0.64). The mean time to first request for post-operative analgesia was432 ± 362 min in Group R, 572 ± 339 min in Group D25 and 614 ± 394 min for Group D50 (P = 0.26). There was significant difference in the heart rate (P = 0.047), mean arterial pressure (P = 0.012) at 30 min and sedation (RASS) score at 15, 30, 60 (P < 0.001) and 120 (P = 0.019) min between the D50 and group R. Patients undergoing buckling procedures had significantly shorter time to request for analgesia (P = 0.003).

Conclusion

Addition of dexmedetomidine does not offer advantage over 0.75% Ropivacaine in PBB for vitrectomy. Its benefit in more painful procedures like scleral buckle needs further validation.

Effect of Topical Dexmedetomidine (0.0055%) on Intraocular Pressure in Healthy Eyes: A Randomized Controlled Trial

Aim and objective

Evaluate the short-term safety and efficacy of dexmedetomidine (0.0055%) drops on intraocular pressure (IOP) in healthy eyes.

Materials and methods

In this randomized controlled trial, patients with normal eye exams were randomly assigned to receive, in a randomly selected eye, one drop of either balanced salt solution (BSS) or dexmedetomidine (0.0055%). Goldmann applanation tonometry was performed at baseline and then 30 minutes, 4 hours, and 24 hours after drop instillation.

Results

Forty-nine eyes of 49 normal volunteers were enrolled in the study, with 21 eyes (group I) receiving BSS and 28 (group II) dexmedetomidine. Both groups were comparable at baseline as far as age and IOP (p = 0.55 for both parameters). Intraocular pressure significantly decreased from baseline in group II at 30 minutes and 4 hours (p = 0.001 and 0.05, respectively). Maximum IOP decrease was obtained at 30 minutes after dexmedetomidine instillation, with a 9% decrease from baseline (mean decrease: 1.15 mm Hg). The percentage of IOP decrease was significantly higher in group II at 30 minutes compared with group I (9 vs 1.1%; p = 0.05). No side effects were recorded.

Conclusion

In this pilot study, dexmedetomidine 0.0055% drops have shown good safety and efficacy in lowering IOP in normal healthy volunteers with no history of glaucoma. This medication has a short onset of action, with a 10% reduction of IOP occurring 30 minutes post-instillation.

Trial registration number

NCT03690622.

How to cite this article

Fakhoury H, Abdelmassih Y, El-Khoury S, et al. The Effect of Topical Dexmedetomidine (0.0055%) on Intraocular Pressure in Healthy Eyes: A Randomized Controlled Trial. J Curr Glaucoma Pract 2021;15(2):58-63.

Effect of dexmedetomidine on intraocular pressure as an additive in peribulbar block during glaucoma surgery

Purpose:

The purpose of this study is to assess the effect of dexmedetomidine on intraocular pressure (IOP) as an additive in peribulbar injections in glaucoma surgeries.

Methods:

A prospective, randomized, double-blind, parallel assignment interventional study was conducted for patients undergoing glaucoma surgeries at a tertiary eye care hospital in North India. Patients were randomized to two groups, Dexmed group and Placebo group. In the Dexmed group, dexmedetomidine (0.4 μg/kg body weight) was given as an additive along with peribulbar block. The primary outcome was change in IOP pre- and postperibulbar injections (IOP before the block, and after 5 and 15 min of the block). Secondary outcome measures were onset of block, adverse effects (bradycardia, hypotension, respiratory depression, and level 4 sedation), and surgeon satisfaction.

Results:

A total of 104 patients were randomized, 52 each in the Dexmed group and Placebo group. The percentage decrease in IOP was significantly more in the Dexmed group than in the Placebo group both at 5 and 15 min' post block (P < 0.05). At 5 min, the mean percent decrease in IOP in Dexmed group was -10.48, whereas it was 2.85 in the Placebo group. At 15 min, the mean percent decrease in IOP was -22.59 and -9.42 in the Dexmed and Placebo group, respectively. There was no significant difference between the two groups in the onset of block and adverse effects. Surgeon satisfaction was significantly greater in the Dexmed group than the Placebo group (P < 0.05).

Conclusion:

Dexmedetomidine lowers IOP significantly in patients undergoing glaucoma surgeries with safe hemodynamic changes and sedative effect.

Brain protective effect and hemodynamics of dexmedetomidine hydrochloride in patients with intracranial aneurysm

The purpose of the study was to investigate the effect of dexmedetomidine hydrochloride (Dex) on the recovery of cognitive function, hemodynamics, and postoperative analgesia in patients undergoing intracranial aneurysm craniotomy. Methods: general anesthesia was performed on patients undergoing intracranial aneurysm craniotomy in neurosurgery. Patients were randomly divided into three groups: Dex 1 group (Dex dose: 1 μg/kg), Dex 2 group (Dex dose: 0.5 μg/kg), and blank control group (normal saline). The changes of heart rate, arterial pressure, intraoperative brain function index, and postoperative pain score were recorded and compared. Results: in Dex 1 group and Dex 2 group, the heart rate of T1 and T2 phase was significantly lower than that of T3-T7 phases (P < 0.05); compared with the control group, the heart rate of Dex 1 group and Dex 2 group was significantly lower (P < 0.05). The average arterial pressure of the control group and Dex groups was significantly different (P < 0.05). Compared with the control group, there were significant differences between Dex 1 group and Dex 2 group: S100 β protein in T7-T10, NSE (neuron specific enolase) in T9 and T10, pain score in T8, T9 and T10 after operation. Conclusion: the application of Dex in the resection of intracranial aneurysms can protect the brain of patients, minimize the influence of operation on hemodynamics, and relieve postoperative pain, which is worthy of clinical application.

Dexmedetomidine as an Additive to Local Anesthesia for Decreasing Intraocular Pressure in Glaucoma Surgery: A Randomized Trial

Background

Nowadays, the peribulbar block is used as a tool in glaucoma surgery. As a side effect, it increases intraocular pressure that raises the need for adjuvant medication to overcome this problem in the diseased eye. Dexmedetomidine has proven to decrease intraocular pressure (IOP) in the non-glaucomatous eye.

Objectives

In a triple-blinded randomized study, dexmedetomidine as an adjuvant to the peribulbar block was used to decrease IOP in the diseased eye.

Methods

We randomized 98 eyes to three groups, including D50 (35 eyes) with dexmedetomidine 50 µg, D25 (33 eyes) with dexmedetomidine 25 µg, or control group (C) (30 eyes) with the plain peribulbar block. The study was randomized triple-blinded, aiming at testing the effect of dexmedetomidine on IOP after block injection.

Results

The pre-injection IOP was 27.71 ± 2.52, 27.25 ± 3.53, and 26.2 ± 3.57 mmHg in groups D50, D25, and C, respectively, then increased to 29.71 ± 1.69, 30.25 ± 2.36 and 29.4 ± 3.756 in groups D50, D25 and C, respectively, with P >0.05. The pressure decreased after the surgery to 10.86 ± 1.478 in group D50, 10.75 ± 1.63 in group D25, and 10.6 ± 1.589 in group C, with no statistical differences (P > 0.05) between the groups.

Conclusions

Dexmedetomidine did not decrease IOP in the glaucomatous eye.

Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.

Evaluation of the effect and safety of dexmedetomidine as an additive to local anesthesia in peribulbar block for vitreoretinal surgery

Purpose:

We conducted a prospective, randomized study to evaluate the efficacy of dexmedetomidine as an additive to peribulbar block for vitreoretinal surgery in terms of onset time of block, hemodynamic stability profile, patient comfort, and surgeon satisfaction.

Methods:

One hundred patients of American Society of Anesthesiologists grade 1 and 2 scheduled for vitreoretinal surgery were randomly assigned into two groups: control group (n = 50) received lignocaine bupivacaine block, and Dex group (n = 50) received lignocaine bupivacaine plus 20 μg dexmedetomidine peribulbar block. Information regarding time for onset of block, hemodynamic data, visual analog scale for pain, sedation levels, total duration of surgery, and surgeon satisfaction levels were collected.

Results:

All the demographic characteristics including age, gender, American Society of Anesthesiologists grade, onset of anesthesia, and duration of surgery were comparable in both groups. At the baseline, there was no statistically significant difference in heart rate, mean arterial pressure, diastolic blood pressure, and respiratory rate between the two groups, with a difference noted in systolic blood pressure at the baseline. There was significant difference noted in the systolic blood pressure and mean arterial pressure at different time intervals with a decreasing trend as time progressed. The mean sedation score was significantly higher in the Dex group than that in the control group. The surgeon satisfaction was higher in the Dex group than that in the control group.

Conclusion:

Dexmedetomidine is a useful and safe drug in combination with lignocaine bupivacaine in peribulbar for vitreoretinal surgery as it maintains hemodynamic stability and provides sedation, which enables full cooperation and potentially better operating conditions.

Dexamethasone Compared to Dexmedetomidine as an Adjuvant to Local Anesthetic Mixture in Peribulbar Block for Vitreoretinal Surgery. A Prospective Randomized Study

BACKGROUND

Dexamethasone or dexmedetomidine may improve the quality of peribulbar block.

AIM

The aim of this study is to compare the effects of adding either dexamethasone or dexmedetomidine to peribulbar block on the efficacy, intraocular pressure (IOP), time to first analgesic request, total analgesic requirement, and side effects in patients undergoing vitreoretinal surgery.

DESIGN

This was a clinical prospective randomized study.

PATIENTS AND METHODS

One hundred and fifty adult patients scheduled for vitreoretinal surgery with peribulbar block were randomized into three groups (50 patients each). Group I received 3.5 ml of 0.5% bupivacaine and 3.5 ml of 2% lidocaine + 1 ml normal Saline. 4 mg dexamethasone and 25 μg dexmedetomidine in 1 ml were added to the local anesthetic mixture in Groups II and III respectively. Onset and duration of sensory and motor blocks, adequate time to start surgery, IOP, time to first request of rescue analgesia, total analgesic consumption, and side effects were recorded. The statistical software SPSS 16 was utilized for statistical analysis.

RESULTS

Dexamethasone and dexmedetomidine groups showed significantly prolonged duration of corneal anesthesia (234.07 ± 1.37 and 233.54.1.97 min respectively), prolonged lid and globe akinesia (194.27 ± 1.63 and 194.73 ± 2.35 min respectively) with prolonged time to first request of analgesia and less consumption of rescue analgesia as compared to control group (P < 0.05) with non significant differences between both groups (P > 0.05). The onset of corneal anesthesia as well as lid and globe akinesia were enhanced in dexmedetomidine group compared to the other two groups (P < 0.05). In addition, the measurement of IOP was significantly less in the dexmedetomidine group after 10 min. All the patients were hemodynamically stable with no side effects observed.

CONCLUSION

The addition of dexamethasone and dexmedetomidine to local anesthetic mixture in peribulbar block for vitreoretinal surgeries provided safe and effective block with prolonged duration and decreased requirements of postoperative analgesia with better quality for dexmedetomidine group regarding the fast onset of the block and reduced IOP.

Effect of intranasal dexmedetomidine on emergence agitation after sevoflurane anesthesia in children undergoing tonsillectomy and/or adenoidectomy

BACKGROUND

Emergence agitation (EA) after sevoflurane anesthesia is common in children during recovery from general anesthesia and may result in postoperative complications. This study investigated safety and effectiveness of intranasal dexmedetomidine in reducing the incidence and severity of EA.

METHODS

This prospective, randomized double-blinded controlled trial included 86 patients scheduled for the tonsillectomy and/or adenoidectomy under general anesthesia with sevoflurane. They were randomly allocated into two groups. Group D received intranasal dexmedetomidine at 1 μg/kg, and Group C received intranasal saline 0.9% after the induction of general anesthesia. Four-point agitation scale and Face, Legs, Activity, Cry and Consolability (FLACC) scale for pain assessment were measured at six time points (after extubation, leaving the operating room, on arrival to postanesthesia care unit [PACU], 10, 20, and 30 min after arrival in PACU). Extubation, emergence, and discharge times were recorded in addition to any adverse effects.

RESULTS

There was a significant difference in the incidence of EA between Groups D and C (6.98% and 58%, respectively, with P = 0.001). The median four-point agitation scales and the median scores of FLACC pain scales of Group D were significantly lower than those of Group C at the all six time points with P < 0.05. Extubation, emergence, and discharge times were comparable in both groups, and none of the subjects reported any adverse effects.

CONCLUSION

This study demonstrates that a 1 μg/kg dose of intranasal dexmedetomidine administered after the induction of anesthesia reduces post-sevoflurane incidence and severity of EA in children undergone tonsillectomy and/or adenoidectomy with no adverse effects and smooth recovery profile.

Optimal Dose of Dexmedetomidine Retrobulbar Anesthesia during Phacoemulsification Cataract Surgery

Background

The cataract surgery anesthesia should be to make the procedure as safe and as satisfactory as possible for all concerned. The recent progress in anesthesia and surgery now allow cataract extraction to be done with minimal physiological changes to the patient. We aimed in the study to compare between two different doses of dexmedetomidine combined with lidocaine and bupivacaine during retrobulbar anesthesia for cataract extraction by phacoemulsification.

Materials and Methods

This study was done on forty patients with cataract. The patients were enrolled in two groups: Group (A):Twenty patients were received 1.5 ml 2% lidocaine + 1.5 ml 0.5% bupivacaine + 0.25 μg/kg of dexmedetomidine and Group (B): Twenty patients were received 1.5 ml 2% lidocaine + 1.5 ml 0.5% bupivacaine + 0.5 μg/kg of dexmedetomidine.

Results

The globe anesthesia duration, globe, and lid akinesia were significantly longer in the Group B than in the Group A (P < 0.05). Intraocular pressure decreased through the first 15 min after anesthesia in the two groups, and the changes were not significant between the two groups but highly significant in every group when compared to its baseline reading. As regards the conscious level in the two groups, there was a significant difference (P < 0.001). Group A is higher regarding score 2 and 3, and Group B higher in score 4.

Conclusions

We concluded that dexmedetomidine 0.25 μg/kg, when added to retrobulbar block for cataract surgery, will significantly increase the duration of retrobulbar block and improve both the surgeon and the patient satisfaction.