Effect of dexmedetomidine premedication on the intraocular pressure changes after succinylcholine and intubation

Intraocular pressure and cardiovascular effects of dexmedetomidine premedication and tiletamine-zolazepam for anesthetic induction in dogs

Background and Aim

The effect of anesthetic drugs on intraocular pressure (IOP) is an important concern in ophthalmic surgery. The impact of dexmedetomidine (DEX) combined with tiletamine-zolazepam on IOP is scarcely studied. This study aimed to evaluate IOP and cardiovascular effects in dogs after premedication with 5 μg/kg (DEX5) or 10 μg/kg (DEX10) of intramuscular DEX followed by intravenous tiletamine-zolazepam administration for induction of anesthesia in healthy dogs.

Materials and Methods

Eighteen dogs, American Society of Anesthesiologists I or II, without ocular abnormality were investigated. All dogs were randomly divided into the DEX5 (n = 9) and DEX10 groups (n = 9). The IOP, heart rate (HR), systolic blood pressure (SBP), oxygen saturation, and sedation scale were measured before premedication (baseline), after premedication at 5, 10, 15, and 20 min, after tiletamine-zolazepam administration, after endotracheal intubation, and post-operative.

Results

There were no significant differences between the groups at any time point. The DEX5 and DEX10 groups had significantly decreased HR values at 10 min compared with baseline. The IOP at 20 min was significantly lower compared to the baseline in the DEX10 group. Moreover, the DEX10 group showed increased IOP, HR, SBP, and sedation scale values after induction and intubation compared with 20 min, but these values did not differ significantly from baseline. All parameters of both groups did not change significantly between post-operative and baseline.

Conclusion

Intramuscular DEX (10 μg/kg) is an appropriate premedication in ophthalmic examination or surgical procedures. Moreover, it could be combined with tiletamine-zolazepam for generalized anesthesia in dogs with an ophthalmic problem, as it had no clinically significant effects on IOP or cardiovascular values.

Effect of dexmedetomidine on hemodynamic responses to tracheal intubation: A meta-analysis with meta-regression and trial sequential analysis

STUDY OBJECTIVE

An uncontrolled adrenergic response during tracheal intubation may lead to life-threatening complications. Dexmedetomidine binds to α2-receptors and may attenuate this response. The primary aim of our meta-analysis is to investigate dexmedetomidine efficacy in attenuating sympathetic response to tracheal intubation, compared with placebo or no dexmedetomidine, in terms of heart rate and blood pressure at intubation.

DESIGN

Meta-analysis with meta-regression and trial sequential analysis.

SETTING

Systematic search from inception until December 1, 2020 in the following databases: Pubmed, Scopus, the Cochrane Central Register of Controlled Trials, EMBASE and Google Scholar.

INTERVENTIONS

All randomized controlled trials investigating intravenous dexmedetomidine as premedication in adult patients undergoing tracheal intubation were included in our study. Studies were included without any language or publication date restriction. A trial sequential analysis and a post-hoc meta-regression were performed on the main outcomes.

MEASUREMENTS

Hemodynamic parameters and heart rate at tracheal intubation, dose of anesthetic needed for induction of anesthesia, total anesthetic requirement throughout the operative procedure, postoperative pain and percentage of patients requiring analgesics at 24 postoperative hours, postoperative nausea and vomiting, intraoperative and postoperative bradycardia, hypotension, dizziness, shivering and/or respiratory depression.

MAIN RESULTS

Ninety-nine included studies randomized 6833 patients. During laryngoscopy, all hemodynamic parameters were significantly greater in the no dexmedetomidine group. In particular, in the dexmedetomidine group, systolic blood pressure differed by -21.8 mm Hg (95% CI -26.6 to -17.1, p-value < 0.001, I² 97%), mean arterial pressure by -12.8 mm Hg (95% CI -15.6 to -10.0, p-value < 0.001, I² 98%), and heart rate by -16.9 bpm (95% CI -19.8 to -13.9, p-value < 0.001, I² 98%).

CONCLUSIONS

Patients receiving premedication with dexmedetomidine for tracheal intubation, compared with no dexmedetomidine, have a lower blood pressure and heart rate, however, the risk of bradycardia and hypotension is relevant and its use during daily practice should be cautiously evaluated for each patient.

Effect of Intravenous Dexmedetomidine on Intraocular Pressure in Patients Undergoing Glaucoma Surgery Under Local Anesthesia: A Pilot Study

PRECIS

Preoperative intravenous (IV) dexmedetomidine produced a 33% reduction in intraocular pressure (IOP) within 15 minutes of administration in patients with glaucoma.

PURPOSE

To evaluate the effect of preoperative IV dexmedetomidine on IOP in adult patients undergoing glaucoma surgery under local anesthesia.

METHODS

In a prospective interventional case series, 12 patients with uncontrolled IOP (IOP>24 mm Hg in both the eyes) with the systemic status of American Society of Anesthesiologists (ASA) classification I-II, received IV dexmedetomidine 0.6 µg/kg 30 minutes preoperatively. The IOP of the nonsurgical eye (measured with Perkins tonometer), the heart rate (HR), and blood pressure (BP) were recorded 5 minutes prior, 15 minutes and 2 hours after IV dexmedetomidine administration, and were compared using analysis of variance and Tukey honestly significant difference tests.

RESULTS

There were 4 women and 8 men with a mean age (±SD) of 60.6±10.4 years. The mean number of antiglaucoma medications was 4.3±1.3. The mean pre-dexmedetomidine IOP was 31.5±5.6 mm Hg. At 15 minutes post-dexmedetomidine administration, the mean and percentage drop in IOP were 10.2±3.2 mm Hg (P=0.001) and 33%±11%, respectively. The mean and percentage drop in systolic BP were 18±20 mm Hg (P=0.01) and 12%±14%, and drop in diastolic BP were 6.5±10 mm Hg (P=0.05) and 7%±11%, respectively. The mean and percentage drop in HR were 2±0.6 bpm (P=0.48) and 2%±13%, respectively. None of the subjects experienced any medication-related adverse effects. At 2 hours, the mean and percentage drop in IOP were 5.3±3 mm Hg and 17%±11%, respectively.

CONCLUSION

In the small sample of (ASA I-II) patients studied, preoperative dexmedetomidine produced a significant drop in IOP (33%) within 15 minutes of IV administration in patients with glaucoma that was reversing at 2 hours, with a good safety profile.

Attenuation of the increase in intraocular pressure with dexmedetomidine: Systematic review with meta-analysis and trial sequential analysis

STUDY OBJECTIVE

Whether dexmedetomidine effectively attenuates the increase in intraocular pressure (IOP) remains inconclusive. We aim to evaluate the effects of dexmedetomidine on IOP in adult patients undergoing surgery which requires general anesthesia and endotracheal intubation.

DESIGN

Systematic review and meta-analysis.

INTERVENTIONS

Intravenous administration of dexmedetomidine during surgery.

MEASUREMENTS

Intraocular pressure.

METHODS

We searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, Google Scholar, Wanfang Data, and China National Knowledge Infrastructure from the inception through April 14, 2020. Randomized control trials which involved adult patients undergoing surgery that required general anesthesia and endotracheal intubation, which compared intravenous administration of dexmedetomidine with placebo regarding the IOP levels, which also provided sufficient information for meta-analysis were considered eligible.

MAIN RESULTS

Twenty-nine randomized control trials were included. The IOP levels are significantly lower in patients receiving dexmedetomidine after the administration of dexmedetomidine [mean difference (MD), -2.04 mmHg; 95% confidence interval (CI), -2.40 mmHg to -1.67 mmHg], after the injection of succinylcholine (MD, -3.84 mmHg; 95% CI, -4.80 mmHg to -2.88 mmHg), after endotracheal intubation (MD, -3.64 mmHg; 95% CI, -4.46 mmHg to -2.82 mmHg), after pneumoperitoneum (MD, -3.12 mmHg; 95% CI, -3.93 mmHg to -2.30 mmHg), and after the patients being placed in a steep Trendelenburg position (MD, -4.12 mmHg; 95% CI, -5.39 mmHg to -2.85 mmHg). Trial sequential analyses for these outcomes are conclusive.

CONCLUSIONS

Dexmedetomidine effectively attenuates the increase in IOP levels, and should be considered especially for at-risk patients.

Evaluation of nebulised dexmedetomidine in blunting haemodynamic response to intubation: A prospective randomised study

Background and Aim:

The process of laryngoscopy and endotracheal intubation is associated with intense sympathetic activity, which may precipitate intra-operative complications. Taking the advantage of dexmedetomidine's good bioavailability and rapid absorption through nasal mucosa; we contemplated this study to evaluate the effects of nebulised dexmedetomidine as a premedication in blunting the haemodynamic response to laryngoscopy and tracheal intubation.

Methods:

This prospective, randomised, comparative study was conducted in 100 American Society of Anesthesiologists (ASA) I, II patients. The primary outcome was to evaluate the effects of dexmedetomidine nebulisation in blunting the stress response to laryngoscopy and intubation. The secondary outcome was to study its adverse effects. The study population was divided randomly into two groups. Control group C (n = 50) received nebulisation with 5 ml of normal saline and group D (n = 50) received 1 μg/kg dexmedetomidine 5 ml 10 min before induction in sitting position.

Results:

Demographics were comparable. Following laryngoscopy and intubation, systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP), response entropy (RE) and state entropy (SE) were markedly increased in the control group whereas in group D there was a fall in SBP (at 1 min-126.64 ± 26.37; P 0.01, 5 min-109.50 ± 16.83; P 0.02, 10 min-106.94 ± 17.01; P 0.03), DBP (at 1 min-83.18 ± 17.89; P 0.001, 5 min-66.40 ± 13.88; P 0.001, 10 min- 62.56 ± 14.91; P 0.01) and MAP (at 1 min-99.68 ± 19.22; P 0.001, 5 min- 84.08 ± 13.66; P 0.003, 10 min- 81.74 ± 14.79; P 0.008), RE and SE which was statistically significant (P 0.002). There was a dose sparing effect of propofol in group D; sedation score was comparable.

Conclusion:

Nebulised dexmedetomidine effectively blunts the stress response to laryngoscopy and intubation with no adverse effects.

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.

Effects of Cisatracurium, Rocuronium, and Mivacurium on Intraocular Pressure During Induction of General Anesthesia in Ophthalmic Surgery

Objective

Maintaining intraocular pressure (IOP) is important in preventing ocular complications in patients undergoing ophthalmic surgery for general anesthesia. The effects of non-depolarizing neuromuscular blockers on IOP remain unclear. The present study compared the effects of cisatracurium, rocuronium, and mivacurium on IOP during induction of general anesthesia in vitreous retinal surgery.

Materials and Methods

In this prospective randomized double-blinded study, 133 patients undergoing vitreous retinal surgery were randomized into one of the three groups: Group cisatracurium (n=45), Group rocuronium (n=44), or Group mivacurium (n=44). Each drug (cisatracurium 0.1 mg kg⁻¹ in Group cisatracurium, rocuronium 0.6 mg kg⁻¹ in Group rocuronium, and mivacurium 0.2 mg kg⁻¹ in Group mivacurium) was administered during induction of anesthesia. IOP and hemodynamic parameters were measured at 1 min before anesthesia induction (T0). Bispectral index (BIS) was maintained between 45 and 55 after propofol administration (T1). Train-of-four stimulation (TOF) was below 0 after muscle relaxant administration (T2) and after laryngeal mask implantation (T3).

Results

Both ipsi-operative and control-operative IOP at T1, T2, and T3 significantly decreased from the baseline values (T0) in all three groups (P<0.05). The IOP changes between T1 and T2 among three groups were similar (P>0.05). The values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) at T1 and T2 significantly decreased in all three groups compared to T0 (P<0.05).

Conclusion

Bilateral IOP significantly decreased from the baseline values in all three groups during the induction phase. Cisatracurium, rocuronium, and mivacurium did not induce significant changes in bilateral IOP.

Effect of Anesthesia on Intraocular Pressure Measured With Continuous Wireless Telemetry in Nonhuman Primates

Purpose

To compare the effects of both injectable anesthesia (ketamine/dexmedetomidine versus ketamine/xylazine) and inhalant anesthesia (isoflurane) on IOP using continuous, bilateral IOP telemetry in nonhuman primates (NHP).

Methods

Bilateral IOP was recorded continuously using a proven implantable telemetry system in five different sessions at least 2 weeks apart in four male rhesus macaques under two conditions: ketamine (3 mg/kg) with dexmedetomidine (50 μg/kg) or ketamine with xylazine (0.5 mg/kg) for induction, both followed by isoflurane for maintenance. IOP transducers were calibrated via anterior chamber manometry. Bilateral IOP was averaged over 2 minutes after injectable anesthetic induction and again after isoflurane inhalant had stabilized the anesthetic plane, then compared to baseline IOP measurements acquired immediately prior to anesthesia (both before and after initial human contact).

Results

When compared to pre-contact baseline measurements, ketamine/dexmedetomidine injectable anesthesia lowers IOP by 1.5 mm Hg on average (P < 0.05), but IOP did not change with ketamine/xylazine anesthesia. IOP returned to baseline levels shortly after isoflurane gas anesthesia was initiated. However, injectable anesthesia lowered IOP by an average of 5.4 mm Hg when compared to that measured after initial human contact (P < 0.01).

Conclusions

Anesthetic effects on IOP are generally small when compared to precontact baseline but much larger when compared to IOP measures taken after human contact, indicating that IOP is temporarily elevated due to acute stress (similar to a "white coat effect") and then decreased with anesthetic relaxation. Anesthetic induction with ketamine/xylazine and maintenance with isoflurane gas should be used when IOP is measured postanesthesia.

The Effects of Intravenous Dexmedetomidine Injections on IOP in General Anesthesia Intubation: A Meta-Analysis

Objective. The aim of this meta-analysis is to evaluate the effects of dexmedetomidine on intraocular pressure (IOP) in patients with general anesthesia administered via intubation. Methods. We searched randomized controlled trials (RCT) on the effects of intravenous injection of dexmedetomidine on IOP in patients with general anesthesia administered via intubation. Results. The meta-analysis study showed that (1) a statistically significant difference [WMD = −3.40 mmHg, 95% CI (−4.76, −2.04), P < 0.00001] was found between IOP of the two groups. (2) The IOP of the dexmedetomidine group that was administrated succinylcholine was lower than that of placebo group which was administrated succinylcholine [WMD = −4.13 mmHg, 95% CI (−6.01, −2.25), P < 0.0001]. (3) Compared with the IOP of patients in the placebo group, patients with intubation in the dexmedetomidine group maintained a lower IOP [WMD = −3.10 mmHg, 95% CI (−5.12, −1.07), P = 0.003]. However, for incidences of bradycardia, the use of dexmedetomidine was higher than that of the placebo [RR = 0.23, 95% CI (0.07, 0.76), P = 0.02]. Conclusion. This meta-analysis showed that, in many cases, dexmedetomidine can lower the IOP of patients with general anesthesia administered by intubation.

To Evaluate the Efficacy of Intravenous Infusion of Dexmedetomidine as Premedication in Attenuating the Rise of Intraocular Pressure Caused by Succinylcholine in Patients Undergoing Rapid Sequence Induction for General Anesthesia: A Randomized Study

Context:

Laryngoscopy and intubation performed during RSI lead to choroidal blood volume increase and an eventual rise in intraocular pressure (IOP). Use of succinylcholine (SCh) causes an undesirable rise in IOP which is further aggravated by laryngoscopy and endotracheal intubation. Dexmedetomidine is a highly selective centrally acting α₂ adrenergic agonist that has IOP lowering properties.

Aims:

This study aims to evaluate the efficacy of intravenous (i.v.) infusion of dexmedetomidine (0.5 μg/kg) as premedication in attenuating the rise of IOP and adverse effect if any caused by SCh in patients undergoing RSI for general anesthesia.

Settings and Design:

This was a double-blind, randomized trial.

Subjects and Methods:

Sixty adult patients in the age group of 20–50 years scheduled for elective surgeries under general anesthesia. Group I (dexmedetomidine group) (n = 30) received i.v. infusion of dexmedetomidine (0.5 μg/kg) and Group II (control group) (n = 30) received i.v. infusion of 50 ml normal saline as premedication

Statistical Analysis Used:

The analysis was done using Statistical Package for Social Sciences Version 15.0 statistical Analysis Software.

Results:

It was observed that Group I (dexmedetomidine group) had a better attenuating effect over the increases in IOP in patients undergoing RSI for general anesthesia using SCh. An increase in IOP was seen in Group II (control group) patients with RSI.

Conclusions:

The findings in the present study indicate that i.v. dexmedetomidine effectively attenuates the increases in IOP with an additional advantage of control on hemodynamic responses following RSI.

The effects of intravenous dexmedetomidine premedication on intraocular pressure and pressor response to laryngoscopy and intubation

Background and Aims:

Penetrating eye injuries are a challenge for the anesthesiologists in emergency due to increase in intraocular pressure (IOP). The aim of this study was to evaluate the effects of intravenous dexmedetomidine premedication on changes in IOP and hemodynamic response following laryngoscopy and tracheal intubation.

Material and Methods:

Hundred patients aged 18-60 years undergoing elective nonophthalmic surgery were divided into two groups of 50 each. Group D received a bolus dose of dexmedetomidine (0.4 μg/kg) diluted to 20 ml normal saline and Group C received normal saline (0.4 ml/kg) over 10 min as premedication. Heart rate (HR), systolic blood pressure (SBP) and IOP were measured and recorded before premedication (T1), 5 and 10 m after premedication (T2, T3), immediately after induction, intubation and then 1, 3, 5 min after intubation (T4, 5, 6, 7, 8).

Results:

HR was comparable in both groups at preoperative level, but it was significantly low in the drug group when compared with the control group at T4-T8 (P = 0.034, P < 0.001, 0.001, 0.036 and 0.001, respectively). The SBP was comparable in both the groups at baseline and till before induction. At T4-T8 there was a fall in SBP in Group D compared to the Group C (P = 0.045, P = 0.007, 0.001, 0.001 and 0.001, respectively). The baseline IOP was comparable in both the groups (P = NS). There was a significant fall in the IOP in Group D, 5 min after the drug infusion compared to Group C, which was sustained till 5 min after intubation (T8) (P < 0.001 at all intervals).

Conclusion:

Dexmedetomidine premedication in the dose of 0.4 μg/kg lowers the IOP and attenuates the pressor response to laryngoscopy and intubation.

Efficacy of alpha2 agonists in obtunding rise in intraocular pressure after succinylcholine and that following laryngoscopy and intubation

Context:

Elevation of intraocular pressure (IOP) is an inherent and inadvertent association with the use of succinylcholine and alpha₂ agonists can be used to obtund this effect.

Aims:

The study was aimed to assess the efficacy of intravenous dexmedetomidine and clonidine premedication in attenuating rise in IOP during laryngoscopy and intubation following administration of succinylcholine.

Settings and Design:

This prospective, observational study was conducted in 40 patients aged 20–60 years undergoing non ophthalmic surgical procedures.

Subjects and Methods:

For patients in Group D, dexmedetomidine 0.4 mcg/kg and in Group C clonidine 1 μg/kg over 10 min was administered before induction. All patients were induced with propofol. Laryngoscopy and intubation were performed 1 min after administration of succinylcholine 2 mg/kg.

Statistical Analysis Used:

Mann–Whitney, Chi-square and Wilcoxon tests.

Results:

Mean baseline IOP of both groups were comparable (15.4 ± 2.6 vs. 14.7 ± 2.3). Following premedication and induction, IOP decreased in both groups and the reduction was significantly more in Group D. Following administration of succinylcholine and 1 min after intubation IOP raised and exceeded the baseline value in Group C (16.0 ± 1.6 and 18.6 ± 2.2). Though there was an increase in IOP in Group D (12.0 ± 1.9 and 14.0 ± 2.1), it did not reach up to baseline values. Then there was a gradual reduction in IOP in both groups at 3, 5, and 10 min and Group D continued to have a significantly low IOP than Group C up to 10 min.

Conclusions:

Dexmedetomidine 0.4 μg/kg resulted in a reduction of IOP and blunted the increase in IOP, which followed administration of succinylcholine, laryngoscopy, and intubation. Though clonidine 1 μg/kg reduced IOP, it did not prevent rise in IOP following succinylcholine, laryngoscopy, and intubation.

A comparative evaluation of the effect of intravenous dexmedetomidine and clonidine on intraocular pressure after suxamethonium and intubation

Background:

In patients with penetrating eye injury and a full stomach, suxamethonium is still used for rapid sequence induction of anesthesia. But its use is associated with the rise in intraocular pressure (IOP) and this can result in permanent vision loss in these patients. Dexmedetomidine and clonidine are two alpha-2 adrenergic agonist drugs which prevent the rise in IOP. The aim of this study is to compare the efficacy of intravenous (i.v.) dexmedetomidine and clonidine in preventing an increase in IOP after administration of suxamethonium and tracheal intubation.

Materials and Methods:

Sixty patients undergoing elective nonophthalmic surgery under general anesthesia were included in this clinical study. Patients were randomly assigned into three groups to receive 0.5 mcg/kg dexmedetomidine (Group D), 2 mcg/kg clonidine (Group C) or normal saline (Group S) as premedication i.v. over a period of 10 min before induction. IOP, heart rate, and mean arterial pressure were recorded before and after premedication, after suxamethonium, after intubation and then after 5 min.

Results:

Following administration of dexmedetomidine and clonidine IOP decreased in both groups. After suxamethonium IOP increased in all three groups but it never crossed the baseline in Group D and C. After laryngoscopy and intubation IOP again increased in all three groups but in dexmedetomidine group it never crossed the baseline whereas in clonidine group it was significantly higher than the baseline.

Conclusion:

Single i.v. dose of dexmedetomidine premedication (0.5 mcg/kg) blunt the IOP and hemodynamic response to suxamethonium injection and tracheal intubation more effectively than single i.v. dose of clonidine premedication (2 mcg/kg).

Low-dose intramuscular dexmedetomidine as premedication: a randomized controlled trial

BACKGROUND

Dexmedetomidine-induced bradycardia or hypotension has recently attracted considerable attention because of potentially grave consequences, including sinus arrest and refractory cardiogenic shock. A route other than intravenous injection or a low dose may help minimize cardiovascular risks associated with dexmedetomidine. However, few studies have addressed the clinical effects of low-dose intramuscular dexmedetomidine as premedication.

MATERIAL AND METHODS

Forty American Society of Anesthesiologists physical status I adult patients undergoing suspension laryngoscopic surgery were randomized to receive intramuscular dexmedetomidine (1 µg·kg-1) or midazolam (0.02 mg·kg-1) 30 minutes prior to anaesthesia induction. The sedative, hemodynamic, and adjuvant anaesthetic effects of both premedications were assessed.

RESULTS

The levels of sedation (Observer's Assessment of Alertness/Sedation scales) and anxiety (visual analog score) at pre-induction, and the times to eye-opening and extubation, were not different between the groups. The heart rate response following tracheal intubation and extubation, and mean arterial pressure responses after extubation, were attenuated in the dexmedetomidine group compared to the midazolam group. No bradycardia or hypotension was noted in any patients. Propofol target concentrations at intubation and at start and completion of surgery were decreased in the dexmedetomidine group, whereas no difference in respective remifentanil levels was detected.

CONCLUSIONS

This study provides further evidence that dexmedetomidine premedication in low dose (1 μg·kg-1) by intramuscular route can induce preoperative sedation and adjuvant anaesthetic effects without clinically significant bradycardia or hypotension.

Changes in intraocular pressure following administration of suxamethonium and endotracheal intubation: Influence of dexmedetomidine premedication

Background:

Use of suxamethonium is associated with an increase in intraocular pressure (IOP) and may be harmful for patients with penetrating eye injuries. The purpose of our study was to observe the efficacy of dexmedetomidine for prevention of rise in IOP associated with the administration of suxamethonium and endotracheal intubation.

Methods:

Sixty-six American Society of Anaesthesiologists I or II patients undergoing general anaesthesia for non-ophthalmic surgery were included in this randomized, prospective, clinical study. Patients were allocated into three groups to receive 0.4 μg/kg dexmedetomidine (group D4), 0.6 μg/kg dexmedetomidine (group D6) or normal saline (group C) over a period of 10 min before induction. IOP, heart rate and mean arterial pressure were recorded before and after the premedication, after induction, after suxamethonium injection and after endotracheal intubation.

Results:

Fall in IOP was observed following administration of dexmedetomidine. IOP increased in all three groups after suxamethonium injection and endotracheal intubation, but it never crossed the baseline value in group D4 as well as in group D6. Fall in mean arterial pressure was noticed after dexmedetomidine infusion, especially in the D6 group.

Conclusion:

Dexmedetomidine (0.6 μg/kg as well as 0.4 μg/kg body weight) effectively prevents rise of IOP associated with administration of suxamethonium and endotracheal intubation. However, dexmedetomidine 0.6 μg/kg may cause significant hypotension. Thus, dexmedetomidine 0.4 μg/kg may be preferred for prevention of rise in IOP.

Comparison of sedative drugs under peribulbar or topical anesthesia during phacoemulsification

BACKGROUND AND OBJECTIVE

To compare dexmedetomidine and midazolam+fentanyl sedation primarily based on patient satisfaction during phacoemulsification under topical and peribulbar anesthesia.

PATIENTS AND METHODS

Prospective, randomized, and double-blind study of 80 American Society of Anesthesiology grade I-II patients who underwent phacoemulsification with local anesthesia under sedation. Patients were divided into four groups (20 patients for each): dexmedetomidine and topical anesthesia, dexmedetomidine and peribulbar anesthesia, midazolam+fentanyl and topical anesthesia, and midazolam+fentanyl and peribulbar anesthesia. Patient and surgeon satisfaction were determined on a 5-point scale. The pain was determined by verbal pain scale intraoperatively and postoperatively. Drugs were given to a Ramsay sedation scale of 3. Topical and peribulbar anesthesia were performed by an ophthalmologist. Hemodynamic, respiratory, and intraocular pressure monitoring was done. Operative and recovery times were recorded.

RESULTS

In the midazolam+fentanyl groups, better patient and surgeon satisfaction scores were obtained (P < .005), verbal pain scale scores were significantly lower (P < .001), and patients needed less postoperative analgesia. Ramsay sedation scale scores were between 3 and 4 in all patients and there were no significant differences. Intraocular pressure alterations were similar between groups. Recovery time was longer in the dexmedetomidine groups (P < .05).

CONCLUSION

The study demonstrated that the midazolam+fentanyl combination provided high-level patient satisfaction scores, low-level pain scores, and shorter recovery time. Also, both of the peribulbar and topical anesthesia procedures showed similar efficiency.

Vitreous humour extrusion after suxamethonium induction of anaesthesia in a polytraumatized patient: a case report

Introduction. Suxamethonium, a deepolarizing muscle relaxant, increases intraocular pressure. It is therefore advised to be avoided in open globe surgery, for fear of extruding ocular contents. Several anecdotal reports support this fear. Some workers however, dispute this claim. There is as yet no formal case report in the literature on the subject. Case Presentation. A 34-year old Nigerian male, was involved in a road traffic accident. He presented at the Accident & Emergency Unit of our hospital about 2 hours after the accident. Clinical examination revealed right corneal laceration (with intact ocular contents) and intra-abdominal visceral injury. Emergency laparotomy was scheduled, to be followed with corneal repair. Anaesthesia was induced with 10 mg midazolam, 100 mg ketamine, and 100 mg suxamethonium given intravenously in sequence. After laparotomy, the ophthalmologists reported for the corneal repair, only to find that the vitreous humour has been extruded. Conclusion. The fear about the use of suxamethonium in open globe situations is real. It will be good clinical judgment to use alternative drugs and techniques to effect rapid muscle relaxation, in the anaesthetic management of the open globe patient. This would be of interest to anaesthetists, ophthalmologists and clinical pharmacologists among others.

Dexmedetomidine: perioperative applications in children

Dexmedetomidine is a highly specific and selective alpha-2-adrenergic agonist with sedative, anxiolytic, and organ protective effects. Its clinical applications in children include premedication, prevention of emergence delirium, as part of multimodal anesthetic regimen and sedation in the pediatric intensive care unit. Its role in neuroprotection in children undergoing anesthesia should be explored. In this review, various uses of dexmedetomidine are discussed in detail.

Bilateral posterior vitreous detachment after electroconvulsive therapy

In this case report, we describe a patient with an acute bilateral posterior detachment of the vitreous, which developed during electroconvulsive therapy (ECT) under general anesthesia. The patient developed symptoms of posterior vitreous detachment immediately after recovery from the eighth ECT session. The ophthalmologist confirmed the clinical diagnosis and ECT was stopped. We review the literature and discuss the ocular side effects of ECT.