Intrathecal midazolam increases the analgesic effects of spinal blockade with bupivacaine in patients undergoing haemorrhoidectomy

Comparison of Fentanyl With Midazolam As Adjuvants to Levobupivacaine in Spinal Anesthesia for Cesarean Sections: A Randomized Controlled Trial

Background and objectives Spinal anesthesia stands as a cornerstone for patients undergoing lower segment cesarean section (LSCS), offering advantages like faster onset and high block density. Levobupivacaine, known for its high potency and long-acting nature, has a slower onset. The safety of intrathecal fentanyl or midazolam is evaluated as an adjuvant to levobupivacaine in parturients. This study aims to compare the duration of postoperative analgesia provided by fentanyl or midazolam added to 0.5% hyperbaric levobupivacaine in elective cesarean sections. Secondary objectives include evaluating the onset and duration of sensory and motor blockade and the incidence of nausea and vomiting. Identifying the more effective adjuvant will help optimize spinal anesthesia protocols, improve postoperative outcomes, and enhance patient comfort and recovery. Methods This study was conducted at SRM Medical College Hospital and Research Centre, Chennai, India, over six months (May 1, 2023, to October 1, 2023). A total of 90 patients undergoing elective LSCS received spinal anesthesia in a prospective randomized double-blinded controlled trial. Patients were allocated to three groups: Group A received levobupivacaine with fentanyl, Group B received levobupivacaine with midazolam, and Group C received levobupivacaine with normal saline. Block characteristics, postoperative analgesia, hemodynamic stability, and complications were assessed. Assessments were conducted at specified time points: intraoperatively, every five minutes for the first 30 minutes, every 10 minutes for the next hour, every two hours for six hours, and every four hours up to 24 hours postoperatively. Statistical analysis utilized one-way analysis of variance (ANOVA). Results Group B (levobupivacaine with midazolam) exhibited a shorter time to sensory block onset (88 seconds) compared to Groups A and C (both 145 seconds) (p < 0.001). Group A (levobupivacaine with fentanyl) showed a shorter time to maximum motor block (p = 0.045) than Groups B and C. The sensory block duration was significantly longer in Group A (127.5 minutes) compared to Group B (60 minutes) and Group C (69 minutes) (p < 0.001). Motor block duration was also prolonged in Group A (251 minutes) compared to Group B (147 minutes) and Group C (177 minutes) (p = 0.045). The first analgesic requirement was delayed in Group A (248 minutes), whereas Groups B (115 minutes) and C (90 minutes) (p < 0.001) required more frequent analgesia. Group A experienced a higher incidence of postoperative nausea and vomiting. Conclusion Midazolam accelerated sensory block onset, while fentanyl prolonged anesthesia duration without significantly affecting motor block. Fentanyl delayed the first analgesic requirement, whereas midazolam reduced postoperative nausea, vomiting, and shivering.

Intradermal methylene blue analgesic application in posthemorrhoidectomy pain management: a randomized controlled trial

Introduction

Unbearable post-hemorrhoidectomy pain is a well-documented challenge, significantly impacting patient well-being and satisfaction after surgery, often influencing patients to decline in undergoing this procedure. It is widely recognized that methylene blue has an effect of reducing inflammation and pain by reduces the production of nitric oxide and inhibiting the action potentials production in nerves. This study aims to explore the potential benefits of postoperative regional administration of methylene blue in providing extended relief from post-hemorrhoidectomy pain.

Methods

This study included 97 patients aged 18-75 undergoing hemorrhoidectomy for stage III or IV hemorrhoids. A double-blind, randomized controlled trial compared postoperative intradermal injections of 1% methylene blue to 0.5% Marcaine as the control group. Two-week follow-up assessed pain. Statistical analysis, adherence to ethical standards, and registration were conducted.

Result

No significant differences were found in baseline demographics, surgical parameters, or complications between the Methylene Blue and control groups. Intervention group remained lower in mean pain score until the 12th day. Methylene blue group reported significantly lower postoperative pain scores from days 1 to 7, with no significant differences afterward.

Conclusion

This ongoing randomized controlled trial reveals the potential analgesic benefits of intradermal injection 1% methylene blue. It demonstrates comparable efficacy in reducing post-hemorrhoidectomy pain, with negligible side effects and complications.

The effect of perioperative benzodiazepine administration on postoperative nausea and vomiting: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Despite recent systematic reviews suggesting their benefit for postoperative nausea, vomiting, or both (PONV) prevention, benzodiazepines have not been incorporated into guidelines for PONV prophylaxis because of concerns about possible adverse effects. We conducted an updated meta-analysis to inform future practice guidelines.

METHODS

We included randomised controlled trials (RCTs) of all languages comparing benzodiazepines with non-benzodiazepine comparators in adults undergoing inpatient surgery. Our outcomes were postoperative nausea, vomiting, or both. We assessed risk of bias for RCTs using the Cochrane Risk of Bias tool. We pooled data using a random-effects model and assessed the quality of evidence for each outcome using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

We screened 31 413 abstracts and 950 full texts. We included 119 RCTs; 104 were included in quantitative synthesis. Based on moderate certainty evidence, we found that perioperative benzodiazepine administration reduced the incidence of PONV (52 studies, n=5086, relative risk [RR]: 0.77, 95% confidence interval [CI] 0.66-0.89; number needed to treat [NNT] 16; moderate certainty), postoperative nausea (55 studies, n=5916, RR: 0.72, 95% CI 0.62-0.83; NNT 21; moderate certainty), and postoperative vomiting (52 studies, n=5909, RR: 0.74, 95% CI 0.60-0.91; NNT 55; moderate certainty).

CONCLUSIONS

Moderate quality evidence shows that perioperative benzodiazepine administration decreases the incidence of PONV. The results of this systematic review and meta-analysis will inform future clinical practice guidelines.

SYSTEMATIC REVIEW PROTOCOL

The protocol for this systematic review was pre-registered with PROSPERO International Prospective Register of Systematic Reviews (CRD42022361088) and published in BMJ Open (PMID 31831540).

Ketamine versus midazolam as an adjuvant to peribulbar block using a single inferonasal injection in patients undergoing vitreoretinal surgery: A randomized controlled trial

INTRODUCTION AND OBJECTIVES

This study aimed to assess the safety and efficacy of midazolam and ketamine as adjuvants to the peribulbar block in vitreoretinal surgeries.

PATIENTS AND METHODS

This randomized controlled trial included 93 adult patients undergoing vitreoretinal surgeries performed with peribulbar anaesthesia. Patients were randomly allocated to 3 groups (31 participants each): control (standard anaesthetic mixture), midazolam (standard mixture + midazolam), and ketamine (standard mixture + ketamine). The primary outcomes were onset of globe akinesia and duration of analgesia. Secondary outcomes were duration of motor blockade, onset of corneal anaesthesia and lid akinesia, and changes in vital data (blood pressure, oxygen saturation, and pulse rate).

RESULTS

The ketamine group vs. the control and midazolam groups showed the most rapid onset of lid and globe akinesia (p < 0.001) and corneal anaesthesia (0.7 ± 0.2 vs. 1.5 ± 0.5 and 1.2 ± 0.4, respectively; p < 0.001) and the longest duration of both analgesia (3.7 ± 0.6 vs. 2.3 ± 0.4 and 3.1 ± 0.6, respectively; p < 0.001) and akinesia (3.8 ± 0.5 vs. 3.0 ± 0.4, and 3.7 ± 0.5, respectively; p < 0.001). The midazolam group showed better outcomes than controls, but the drug was less effective than ketamine. There were no significant differences in vital data among groups (p > 0.05).

CONCLUSIONS

Ketamine is an effective adjuvant for peribulbar blockade. It enhances both motor and sensory blockade by hastening onset and prolonging duration. These effects are desirable in lengthier ophthalmic procedures such as vitreoretinal surgeries. The effects of ketamine were superior to those of midazolam.

Effect of Combined Epidural Morphine and Midazolam on Postoperative Pain in Patients Undergoing Major Abdominal Cancer Surgery

OBJECTIVE

The objective was to compare analgesic effect of combined epidural morphine-midazolam with either drug alone on postoperative pain in patients undergoing major abdominal cancer surgery.

MATERIALS AND METHODS

Eighty-four patients were allocated in prospective randomized double-blind study to receive epidural analgesia. Patients received 5 mg morphine in morphine (Mor) group, 5 mg midazolam in midazolam (Mid) group, 5 mg morphine + 5 mg midazolam in morphine-midazolam (MM) group, 0.25% bupivacaine was added to injected solution with same volume in all groups. All groups were compared with time of first analgesic request, total analgesic consumption, number of epidural doses, postoperative Visual Analog Scale score, and adverse events.

RESULTS

Time of first analgesic request was 4 to 8 hours in Mid versus 12 to 23 and 14 to 24 hours in Mor and MM groups, respectively, with significant difference between Mid versus Mor ( P <0.001), Mid versus MM ( P <0.001), and Mor versus MM groups ( P <0.031). Analgesic consumption was more in Mid than Mor and MM groups, with significant difference between Mid versus Mor ( P <0.008), Mid versus MM ( P <0.001), with no significant difference between Mor and MM groups ( P <0.6). The number of epidural doses in Mid was 1 to 3 versus 1 to 3, and 1 to 2 in Mor and MM groups, respectively, with significant difference between Mid versus Mor ( P <0.025), Mid versus MM ( P <0.004), with no significant difference between Mor and MM groups ( P =1.0).

CONCLUSIONS

Addition of midazolam to epidural morphine prolonged time of first analgesic request and decreased total analgesic consumption.

Strategies to Reduce Post-Hemorrhoidectomy Pain: A Systematic Review

Background and Objectives: Excisional hemorrhoidectomy is considered as a mainstay operation for high-grade hemorrhoids and complicated hemorrhoids. However, postoperative pain remains a challenging problem after hemorrhoidectomy. This systematic review aims to identify pharmacological and non-pharmacological interventions for reducing post-hemorrhoidectomy pain. Materials and Methods: The databases of Ovid MEDLINE, PubMed and EMBASE were systematically searched for randomized controlled trails (published in English language with full-text from 1981 to 30 September 2021) to include comparative studies examining post-hemorrhoidectomy pain as their primary outcomes between an intervention and another intervention (or a sham or placebo). Results: Some 157 studies were included in this review with additional information from 15 meta-analyses. Fundamentally, strategies to reduce post-hemorrhoidectomy pain were categorized into four groups: anesthetic methods, surgical techniques, intraoperative adjuncts, and postoperative interventions. In brief, local anesthesia-alone or combined with intravenous sedation was the most effective anesthetic method for excisional hemorrhoidectomy. Regarding surgical techniques, closed (Ferguson) hemorrhoidectomy performed with a vascular sealing device or an ultrasonic scalpel was recommended. Lateral internal anal sphincterotomy may be performed as a surgical adjunct to reduce post-hemorrhoidectomy pain, although it increased risks of anal incontinence. Chemical sphincterotomy (botulinum toxin, topical calcium channel blockers, and topical glyceryl trinitrate) was also efficacious in reducing postoperative pain. So were other topical agents such as anesthetic cream, 10% metronidazole ointment, and 10% sucralfate ointment. Postoperative administration of oral metronidazole, flavonoids, and laxatives was associated with a significant reduction in post-hemorrhoidectomy pain. Conclusions: This systematic review comprehensively covers evidence-based strategies to reduce pain after excisional hemorrhoidectomy. Areas for future research on this topic are also addressed at the end of this article.

To Compare the Efficacy of Postoperative Analgesia between Clonidine and Dexmedetomidine as Adjuvants with 0.5% Ropivacaine by Ultrasound-Guided Supraclavicular Brachial Plexus Block for Upper Limb Surgeries: A Prospective, Double-Blind, Randomized Study

Context:

The supraclavicular brachial plexus block is a very safe, useful and effective method for upper limb surgeries. Among local anesthetics, ropivacaine has special applications in neuraxial and peripheral nerve blocks due to its low cardiotoxicity and less toxicity to central nervous systems compared to bupivacaine and lignocaine. Dexmedetomidine is a newer and potent alpha-2 receptor agonist which has 10 times higher selectivity for alpha-2 receptors as compared to clonidine, So far, very few studies have been undertaken to compare the efficacy of clonidine and dexmedetomidine to provide and prolong postoperative analgesia, especially with the use of ultrasound for nerve localization.

Aims:

To compare the efficacy of postoperative analgesia between clonidine and dexmedetomidine as adjuvants with 0.5% ropivacaine by ultrasound-guided supraclavicular brachial plexus block for upper limb surgeries.

Settings and Design:

Prospective, randomised, double-blind interventional study.

Subjects and Methods:

Eighty patients of ASA grade I or II undergoing elective upper limb surgery were randomly divided into two groups:- Group RC (n = 40) received 35 ml of 0.5% ropivacine with 1 μg.kg⁻¹ of clonidine. Group RD (n = 40) received 35 ml of 0.5% ropivacaine with 1 μg.kg⁻¹ of dexmedetomidine.

Statistical analysis used:

The statistical software SPSS version 20 has been used for the analysis. By using Pearson's Chi-Square test for Independence of Attributes/Fisher's Exact. Continuous variables were expressed as Mean, Median, and Standard Deviation and compared across the groups using unpaired t-test.

Results:

In our comparative study, dexmedetomidine 1 μg.kg⁻¹ with 35 ml of 0.5% ropivacaine provided significantly longer duration of postoperative analgesia and earlier sensory block as compared to clonidine 1 μg.kg⁻¹ with same dose of ropivacaine in ultrasound-guided supraclavicular brachial plexus block.

Conclusions:

The ropivacaine-dexmedetomidine group in our study provided earlier sensory block and more prolonged postoperative analgesia as compared to ropivacaine-clonidine group. Thus ropivacaine-dexmedetomidine combination may be effectively used in all painful upper limb surgeries specially orthopaedic procedures.

Effect of Oral Midazolam in Pain Relief of Patients Need Nasogastric Tube Insertion: A Clinical Trial Study

Objective:

Due to the presence of pain during nasogastric tube (NGT) insertion and related complications and lack of positive clinical response of nasopharyngeal anesthesia with lidocaine and the related side effects and limitations in ketamine and intravenous midazolam, this study aims to determine the efficacy of oral midazolam in relieving pain in the patients requiring NGT insertion.

Methods:

A randomized, triple-blind clinical trial was performed on the patients in the Emergency Department of Zanjan Valiasr and Mousavi Hospitals in Iran, who were nominated for NGT. In each group, 100 patients were examined. Two milligram syrups of midazolam and placebo were administered 20 min before the procedure. In two groups, the pain based on the Visual Analog Scale and satisfaction rate of patients during the NGT insertion were compared. The data were analyzed through the SPSS software version 16.0.

Findings:

There was no statistically significant difference in the demographic characteristics of two groups. Despite the effects of potential confounding variables, the cause of the referral and indication of NGT, as well as the use of midazolam syrup, had a significant relationship with the outcome, so that midazolam group experienced less pain. The mean and standard deviation of the examined outcomes (feeling of pain and satisfaction with NGT insertion) was statistically significantly different in the midazolam group as compared to the placebo group (P = 0.001).

Conclusion:

Midazolam was effective in decreasing pain and increasing the satisfaction of patients after NGT insertion. This manuscript is registered in Irct. com with code IRCT20110629006922N4.

Nalbuphine versus Midazolam as an Adjuvant to Intrathecal Bupivacaine for Postoperative Analgesia in Patients Undergoing Cesarean Section

Background and Purpose

Adding adjuvants to intrathecal hyperbaric bupivacaine provides long analgesic duration with less adverse effects. The aim of this study was to compare intrathecal nalbuphine versus midazolam in patients undergoing cesarean section.

Clinical Trial ID

NCT03918187.

Patients and Methods

This was a prospective randomized controlled study conducted on 90 females undergoing cesarean section under spinal anesthesia who were randomly allocated to three equal groups of 30 patients each: group C received hyperbaric bupivacaine 12.5 mg plus 0.5 mL saline, group N received hyperbaric bupivacaine 12.5 mg plus 1 mg nalbuphine, group M received hyperbaric bupivacaine 12.5 mg plus 2.5 mg midazolam. The onset and duration of sensory and motor block, effective analgesic time, analgesic requirements, adverse effects, sedation, and Apgar scores were recorded.

Results

There was significant rapid onset of sensory and motor block (1.95±.44 and 3.50±0.43 min) with slower regression of sensory block and time to bromage I (211.6±13.2 and 219.8±20.2 min) in group N compared to groups M, C (p < 0.001), with statistically significant rapid onset and long duration of both blocks in group M compared to C (p<0.001). The effective analgesic time was significantly prolonged in group N (263.7±16.3) compared to groups M and C (224.2 ± 18.6, 185.5±17.45), respectively, (p<0.001) and prolonged in group M compared to C (p<0.001), with increase in analgesic requirement in group C compared to groups N and M (p<0.001) and no significant difference between groups N and M. There was higher sedation score in groups N, M (1.78±0.63, 2.75±0.54), respectively, compared to group C (0.61±0.12) (p<0.001) with lower Apgar score in group M (6.9±0.73) at one minute than in groups N, C (7.1±0.91, 7.7±0.84) (p<0.001). There was no significant difference between groups regarding the adverse effects.

Conclusion

Adding 1 mg nalbuphine to 12.5 mg hyperbaric bupivacaine provided more effective postoperative analgesia than adding 2.5 mg midazolam, with less non-significant adverse effects in midazolam group in patients undergoing elective cesarean section.

Efficacy of midazolam addition to local anesthetic in peribulbar block : Randomized controlled trial

BACKGROUND

Peribulbar block is considered a safe option for patients undergoing cataract surgery. The limited duration of regional eye blocks was shown to be the main problem. The objective of this study was to evaluate the effects of adjuvant midazolam (in two concentrations) to lidocaine in the peribulbar block.

MATERIAL AND METHODS

This study included 90 adult patients aged 40-70 years undergoing cataract surgery. Each patient was appointed to one of three groups. Group C received a single injection of a peribulbar block using a combination of lidocaine 2% and hyaluronidase 15 IU/ml, group M1 received a combination of lidocaine 2%, hyaluronidase 15 IU/ml plus midazolam 50 µg/ml and group M2 received lidocaine 2%, hyaluronidase 15 IU/ml plus midazolam 100 µg/ml.

RESULTS

The quality of the peribulbar block showed significant improvement among groups by one-way ANOVA (p = 0.002). The mean onset time of the sensory block was significantly shorter in the M2 and M1 groups (1.66 min and 2.17 min, respectively) compared to the control group C (2.52 min), while the onset of lid and globe akinesia lacked significance between the three groups (p = 0.23 and 0.06, respectively). Significance in mean values was found between the control (C) and M2 groups regarding orbicularis oculi function, digital spear pressure, topical anesthetic sting and the total score (P-values = 0.004, 0.016, 0.033 and 0.001, respectively). The duration of lid akinesia and sensory anesthesia were significantly different between the three groups (P = 0.048 and P<0.001, respectively) whereas the duration of globe akinesia was insignificant (P = 0.432).

CONCLUSION

Addition of midazolam to local anesthetic significantly improved the quality of peribulbar block, hastened the onset of sensory anesthesia, lid and globe akinesia and increased the duration of analgesia without notable side effects.

Use of intrathecal midazolam or fentanyl as an adjunct to spinal anaesthesia with bupivacaine for lower limb surgery: A randomised controlled study

Background

Intrathecal adjuncts have been used to prolong the quality and duration of subarachnoid anaesthesia. Midazolam given intrathecally is reported to have antinociceptive properties. The purpose of this study was to compare intrathecal midazolam with fentanyl for pain relief and patient comfort.

Methods

In this prospective, double-blind, randomised controlled trial, 90 patients for lower limb surgeries were randomly allocated to three groups: "control group" (3 ml 0.5% heavy bupivacaine), "fentanyl group" (3 ml 0.5% bupivacaine + 10 mcg fentanyl) and "midazolam group" (3 ml 0.5% bupivacaine + 1 mg midazolam). Level, duration, and quality of blocks were compared along with the duration and quality of postoperative analgesia. Haemodynamic stability and any associated complications were also noted.

Results

Onset of block was fastest in Group C (28.5 ± 13.48 min) vis-a-vis other groups (35.5 ± 26.05 min for Group "F" and 28.5 ± 23.68 min for Group "M"; P = 0.51). Duration of block was comparable in all groups (130.5 ± 39.3 min Group "C"; 126.5 ± 44.0 min Group "F" and 129.5 ± 45.7 min Group "M"; P > 0.5).Addition of adjuncts did not significantly defer the appearance of pain. Intensity of pain was lower in Group "M". Average VAS scores were lower for Group "M" (3-4) than those for Group "C" (4-5) and Group "F" (4-6).Majority of patients required at least one dose of rescue analgesic; however, those receiving fentanyl reported better quality of postoperative analgesia than those in midazolam group.

Conclusion

Adjuvants improve quality of postoperative analgesia (fentanyl better than midazolam).

Dexmedetomidine as an Additive to Spinal Anaesthesia in Orthopaedic Patients Undergoing Lower Limb Surgeries: A Randomized Clinical Trial Comparing Two Different Doses of Dexmedetomidine

INTRODUCTION

Use of dexmedetomidine as an additive to spinal anaesthesia is gaining popularity; but there seems to be no clear consensus on the ideal dose to be used. Because of dose related prolongation of duration of motor blockade along with increase in the incidence of side effects of dexmedetomidine namely hypotension and bradycardia, use of higher doses is not recommended.

AIM

To evaluate the efficacy of two different doses of dexmedetomidine (3 μg and 5 μg) given in combination with 0.5% hyperbaric bupivacaine via intrathecal route with regard to the quality of anaesthesia namely the time to attain highest sensory and motor blockade, side effects of dexmedetomidine and time to first rescue analgesia.

MATERIALS AND METHODS

Sixty American Society of Anaesthesiologist (ASA) Grade I and II orthopaedic patients undergoing lower limb surgeries between the ages of 20-60 years and height >150 cm were randomly divided into two groups of 30 patients each: Group D3 to receive 3 μg of Inj. Dexmedetomidine (0.5 ml, reconstituted using normal saline) along with 12.5 mg (2.5 ml) of 0.5% hyperbaric bupivacaine and Group D5 to receive 5 μg of inj. Dexmedetomidine (0.5 ml, reconstituted using normal saline) along with 12.5 mg (2.5 ml) of 0.5% hyperbaric bupivacaine keeping the total volume of study drug constant in all 60 patients (3 ml). Data recordings were done for time to reach best sensory and motor block, intraoperative haemodynamic changes and time to first postoperative rescue analgesia. Statistical analysis was done using student's t-test and Chi-square test with p-value of <0.05 considered to be significant.

RESULTS

The two groups analysed were similar in terms of demographic profile, time to reach highest sensory block (T10) dermatome, time to reach Bromage scale 4, time to surgical incision after spinal and the total duration of surgery (p>0.05). The change in haemodynamics was similar (p>0.05). A statistically significant difference (p<0.001) was observed in time to first rescue analgesia after skin closure with Group D3 having 206.47 minutes while in Group D5 the time was 271.33 minutes.

CONCLUSION

Used in a dose of 5 μg (in 0.5 ml volume) as an additive in spinal anaesthesia maximal beneficial effect of dexmedetomidine can be obtained without any side effects.

B. S, Pandarpurkar S, Jajee P. Intrathecal Midazolam as an Adjuvant in Pregnancy-Induced Hypertensive Patients Undergoing an Elective Caesarean Section: A Clinical Comparative Study

Background

A pain-free postoperative period is essential following a caesarean section so new mothers may care for and bond with their neonates. Intrathecal adjuvants are often administered during this procedure to provide significant analgesia, but they may also have bothersome side effects. Intrathecal midazolam produces effective postoperative analgesia with no significant side effects.

Objectives

This prospective, randomized, double-blind study was designed to compare the analgesic efficacy and safety of intrathecal midazolam vs. plain bupivacaine as an adjunct to bupivacaine in pregnancy-induced hypertension patients scheduled for elective caesarean section.

Methods

Sixty patients diagnosed with pregnancy-induced hypertension on regular treatment who were scheduled for a caesarean section were randomly allocated into two groups: a control group (Group BC, n = 30) and a midazolam group (Group BM, n = 30). Both groups received 10 mg (2 mL) of 0.5% hyperbaric bupivacaine. Group BC received 0.4 mL of distilled water, while group BM received 0.4 mL (2 mg) of midazolam intrathecally. The duration of postoperative analgesia, analgesic requirements during the first 24 hours after surgery, onset times and durations of sensory and motor blocks, incidence of hypotension, vasopressor requirements, and side effects were recorded.

Results

Postoperative analgesia was significantly longer in the midazolam group compared to the control group (201.5 minutes vs. 357.6 minutes). The mean onset times of the sensory and motor blocks were significantly faster (P < 0.01) in the midazolam group compared to the control group. The mean times to attain the maximum sensory level and motor blocks were also significantly faster in the midazolam group compared to the control group (P < 0.05). The incidence of hypotension was 6.6% in the midazolam group and 36.6% in the control group, which was highly significant. In addition, the number of patients with side effects was significantly lower in the midazolam group compared to the control group.

Conclusions

Intrathecal midazolam 2 mg provides significantly longer and effective postoperative analgesia with no side effects.

Dexmedetomidine versus midazolam as adjuvants to intrathecal bupivacaine: A clinical comparison

BACKGROUND AND AIMS

Trials are being carried out to identify an adjuvant to intrathecal bupivacaine that preferably potentiates postoperative analgesia. This prospective, randomized, double-blind study was aimed to compare the onset and duration of sensory and motor block, postoperative analgesia and adverse effects of dexmedetomidine or midazolam given with 0.5% hyperbaric bupivacaine for spinal anesthesia.

MATERIAL AND METHODS

A total of 80 patients, scheduled for vaginal hysterectomies, were randomly allocated to Group D (n = 40) to receive intrathecally 3.0 mL 0.5% hyperbaric bupivacaine +5 ug dexmedetomidine in 0.5 mL of normal saline; and Group M (n = 40) to receive 3 mL of 0.5% hyperbaric bupivacaine +2 mg midazolam in 0.4 mL (5 mg/mL) +0.1 mL normal saline. The onset, duration of sensory and motor block, time to first postoperative analgesia and side effects were noted. Power and Sample size (PS) version 3.0.0.34 was used for power and sample size calculation. Statistical analysis was performed using Microsoft (MS) Office Excel software with the Student's t-test and Chi-square test (level of significance P = 0.05).

RESULTS

Duration of sensory, motor blockade and time to the first requirement of analgesia were significantly higher in Group D. Postoperative visual analog scale was significantly less in Group D than Group M. Both groups were similar with respect to sedation, hemodynamic variables and side-effects.

CONCLUSION

Intrathecal dexmedetomidine was better adjuvant than midazolam as it produces significantly longer duration of sensory block, reduced doses of postoperative analgesic agents with comparable side-effects.

A randomised controlled trial comparing the effect of adjuvant intrathecal 2 mg midazolam to 20 micrograms fentanyl on postoperative pain for patients undergoing lower limb orthopaedic surgery under spinal anaesthesia

BACKGROUND

Intrathecal adjuvants are added to local anaesthetics to improve the quality of neuraxial blockade and prolong the duration of analgesia during spinal anaesthesia. Used intrathecally, fentanyl improves the quality of spinal blockade as compared to plain bupivacaine and confers a short duration of post-operative analgesia. Intrathecal midazolam as an adjuvant has been used and shown to improve the quality of spinal anaesthesia and prolong the duration of post-operative analgesia. No studies have been done comparing intrathecal fentanyl with bupivacaine and intrathecal 2 mg midazolam with bupivacaine.

OBJECTIVE

To compare the effect of intrathecal 2mg midazolam to intrathecal 20 micrograms fentanyl when added to 2.6 ml of 0.5% hyperbaric bupivacaine, on post-operative pain, in patients undergoing lower limb orthopaedic surgery under spinal anaesthesia.

METHODS

A total of 40 patients undergoing lower limb orthopaedic surgery under spinal anaesthesia were randomized to two groups. Group 1: 2.6mls 0.5% hyperbaric bupivacaine with 0.4mls (20micrograms) fentanyl Group 2: 2.6mls of 0.5% hyperbaric bupivacaine with 0.4mls (2mg) midazolam.

RESULTS

The duration of effective analgesia was longer in the midazolam group (384.05 minutes) as compared to the fentanyl group (342.6 minutes). There was no significant difference (P 0.4047). The time to onset was significantly longer in midazolam group 17.1 minutes as compared to the fentanyl group 13.2 minutes (P 0.023). The visual analogue score at rescue was significantly lower in the midazolam group (5.55) as compared to the fentanyl group 6.35 (P - 0.043).

CONCLUSION

On the basis of the results of this study, there was no significant difference in the duration of effective analgesia between adjuvant intrathecal 2 mg midazolam as compared to intrathecal 20 micrograms fentanyl for patients undergoing lower limb orthopaedic surgery.

Efficacy of intrathecal midazolam in potentiating the analgesic effect of intrathecal fentanyl in patients undergoing lower limb surgery

Introduction:

The intrathecal administration of combination of drugs has a synergistic effect on the subarachnoid block characteristics. This study was designed to study the efficacy of intrathecal midazolam in potentiating the analgesic duration of fentanyl along with prolonged sensorimotor blockade.

Materials and Methods:

In a double-blind study design, 75 adult patients were randomly divided into three groups: Group B, 3 ml of 0.5% hyperbaric bupivacaine; Group BF, 3 ml of 0.5% hyperbaric bupivacaine + 25 mcg of fentanyl; and Group BFM, 3 ml of 0.5% hyperbaric bupivacaine + 25 mcg of fentanyl + 1 mg of midazolam. Postoperative analgesia was assessed using visual analog scale scores and onset and duration of sensory and the motor blockade was recorded.

Results:

Mean duration of analgesia in Group B was 211.60 ± 16.12 min, in Group BF 420.80 ± 32.39 min and in Group BFM, it was 470.68 ± 37.51 min. There was statistically significant difference in duration of analgesia between Group B and BF (P = 0.000), between Group B and BFM (P = 0.000), and between Group BF and BFM (P = 0.000). Both the onset and duration of sensory and motor blockade was significantly prolonged in BFM group.

Conclusion:

Intrathecal midazolam potentiates the effect of intrathecal fentanyl in terms of prolonged duration of analgesia and prolonged motor and sensory block without any significant hemodynamic compromise.

Midazolam as an adjuvant to intrathecal lignocaine: A prospective randomized control study

CONTEXT

Unfortunately in the past decade, phenomenon of transient neurologic symptoms (TNS) cast doubts on the use of lignocaine for spinal anesthesia. Intrathecal midazolam has been proved to have its role in relieving neuropathic pain. We attempted to study the role of midazolam as an adjuvant to intrathecal lignocaine.

AIMS

The primary objective of the study was to evaluate the effect of intrathecal midazolam as an adjuvant to spinal lignocaine in terms of quality and duration of spinal sensory blockade. The secondary objectives are to study the effect on hemodynamics and the incidence of TNS.

SETTINGS AND DESIGN

A prospective randomized control double-blinded study in American Society of Anesthesiology I and II surgical population.

MATERIALS AND METHODS

Hundred healthy adult patients scheduled for elective infraumbilical surgery were randomly assigned to group A patients received spinal anesthesia with 1.5 ml of 5% lignocaine heavy with 0.4 ml of 0.9% saline and group B (control group) received spinal anesthesia with 1.5 ml of 5% heavy lignocaine with 0.4 ml of preservative-free 0.5% midazolam.

STATISTICAL ANALYSIS USED

Z test for study parameters and analysis of variance was used for hemodynamic parameters in the same group. P < 0.05 was considered statistically significant.

RESULTS

Midazolam resulted in improved quality of sensory blockade in terms of early onset, increased duration of effective analgesia, and delayed two segment regression time and also decreases the incidence of TNS with intrathecal lignocaine.

CONCLUSIONS

Midazolam is an effective adjuvant to intrathecal lignocaine.

Effect of Two Different Doses of Dexmedetomidine as Adjuvant in Bupivacaine Induced Subarachnoid Block for Elective Abdominal Hysterectomy Operations: A Prospective, Double-blind, Randomized Controlled Study

OBJECTIVES

Improvements in perioperative pain management for lower abdominal operations has been shown to reduce morbidity, induce early ambulation, and improve patients' long-term outcomes. Dexmedetomidine, a selective alpha-2 agonist, has recently been used intrathecally as adjuvant to spinal anesthesia to prolong its efficacy. We compared two different doses of dexmedetomidine added to hyperbaric bupivacaine for spinal anesthesia. The primary endpoints were the onset and duration of sensory and motor block, and duration of analgesia.  .

METHODS

A total of 100 patients, aged 35-60 years old, assigned to have elective abdominal hysterectomy under spinal anesthesia were divided into two equally sized groups (D5 and D10) in a randomized, double-blind fashion. The D5 group was intrathecally administered 3ml 0.5% hyperbaric bupivacaine with 5µg dexmedetomidine in 0.5ml of normal saline and the D10 group 3ml 0.5% bupivacaine with 10µg dexmedetomidine in 0.5ml of normal saline. For each patient, sensory and motor block onset times, block durations, time to first analgesic use, total analgesic need, postoperative visual analogue scale (VAS) scores, hemodynamics, and side effects were recorded.  .

RESULTS

Although both groups had a similar demographic profile, sensory and motor block in the D10 group (p<0.050) was earlier than the D5 group. Sensory and motor block duration and time to first analgesic use were significantly longer and the need for rescue analgesics was lower in the D10 group than the D5 group. The 24-hour VAS score was significantly lower in the D10 group (p<0.050). Intergroup hemodynamics were comparable (p>0.050) without any appreciable side effects.  .

CONCLUSION

Spinal dexmedetomidine increases the sensory and motor block duration and time to first analgesic use, and decreases analgesic consumption in a dose-dependent manner.

Efficacy of clonidine as an adjuvant to ropivacaine in supraclavicular brachial plexus block: A prospective study

Background and Aims:

Bupivacaine has been the most frequently used local anaesthetic in brachial plexus block, but ropivacaine has also been successfully tried in the recent past. It is less cardiotoxic, less arrhythmogenic, less toxic to the central nervous system than bupivacaine, and it has intrinsic vasoconstrictor property. The effects of clonidine have been studied in peripheral nerve blockade. The purpose of this study was to evaluate the effects of clonidine on nerve blockade during brachial plexus block with ropivacaine using peripheral nerve stimulator.

Methods:

Sixty patients were randomly divided into two groups, Group A and B. Group A received 30 ml of 0.5% of ropivacaine with 0.5 ml normal saline while Group B received same amount of ropivacaine with 0.5 ml (equivalent to 75 μg) of clonidine for supraclavicular brachial plexus block. The groups were compared regarding quality of sensory and motor blockade, duration of post-operative analgesia and intra and post-operative complications.

Results:

There was a significant increase in duration of motor and sensory block and analgesia in Group B as compared to Group A patients (P < 0.0001). There was no significant difference in onset time in either group (P = 0.304). No significant side effects were noted.

Conclusion:

The addition of 75 μg of clonidine to ropivacaine for brachial plexus block prolongs motor and sensory block and analgesia without significant side effects.

Effect of different doses of dexmedetomidine as adjuvant in bupivacaine -induced subarachnoid block for traumatized lower limb orthopaedic surgery: a prospective, double-blinded and randomized controlled study

BACKGROUND AND AIMS

Improved pain management for blunt trauma to the lower extremity has shown to reduce morbidity, induce early ambulation and improve long-term outcomes. Dexmedetomidine; a selective α-2 agonist; has recently been used intrathecally in different doses to prolong spinal anaesthesia. We evaluated the effect of adding two different doses of dexmedetomidine to hyperbaric bupivacaine for spinal anaesthesia. The primary endpoints were the onset and duration of sensory, motor block and duration of analgesia.

MATERIALS AND METHODS

Eighty patients, (20-60yrs) posted for elective lower limb orthopedic surgery of traumatic origin under spinal anaesthesia were divided into 2 equal groups (Group D5&D10) in a randomized, double-blind fashion. In this prospective parallel group study, group D5(n=40) 3ml 0.5% hyperbaric bupivacaine+5μg dexmedetomidine in 0.5 ml of normal saline and group D10 (n=40) 3ml 0.5% bupivacaine+10μg dexmedetomidine in 0.5 ml of normal saline were administered intrathecally. Sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, postoperative VAS, hemodynamics and side effects were recorded for each patient.

RESULTS

Though with similar demographic profile in both groups, sensory and motor block in group D10(p<0.05) was earlier than group D5. Sensory, motor block duration and time to first analgesic use were significantly longer and the need for rescue analgesics was lower in group D10(p<0.05) than D5. 24 h VAS score was significantly lower in group D10(p<0.05). Intergroup hemodynamics was comparable (p>0.05) without any appreciable side effects.

CONCLUSION

Spinal dexmedetomidine increases the sensory, motor block duration and time to first analgesic use, and decreases analgesic consumption in a dose-dependent manner.

Reduction in labor pain by intrathecal midazolam as an adjunct to sufentanil

BACKGROUND

Anesthesia today has strived to decrease labor pain in a tolerable and controllable fashion. Intrathecal midazolam has been introduced as an adjunct to analgesics. The study was planned to assess the efficacy, safety and duration of analgesia produced by intrathecal midazolam adjunct to sufentanil in decreasing labor pain.

METHODS

In a randomized clinical trial 80 parturient included in the study. The two groups were matched for age, cervical dilation, gravid, gestational age, and other demographic characteristics. Combination of sufentanil and midazolam administered intrathecally to experimental group and compared to sufentanil group. Time to reach maximum block, and pain score was measured and recorded.

RESULTS

Groups were matched for age and weight and other demographic characteristic. No significant adverse effect was seen in both groups including decrease in Apgar score. Duration of analgesia was 92.0 ± 12.7 in sufentanil group and 185.2 ± 15.2 minutes in midazolam and sufentanil group which was significantly different (P = 0.002). Numeric rating scale score was significantly lower in midazolam group compare to sufentanil group at 120 min (P = 0.01), 150 min (P = 0.0014), and 180 min (P = 0.001).

CONCLUSIONS

Intrathecal midazolam as an adjunct to opioid could significantly enhance analgesia in labor pain with no significant adverse effect. Intrathecal injection of midazolam is an appropriate alternative to parenteral or epidural analgesia in small hospital settings.

A study to compare the analgesic efficacy of intrathecal bupivacaine alone with intrathecal bupivacaine midazolam combination in patients undergoing elective infraumbilical surgery

Spinal anaesthesia, which is one of the techniques for infraumbilical surgeries, is most commonly criticized for limited duration of postoperative analgesia. Several adjuvants have been tried along with local anesthetic for prolonging the duration of analgesia. In this study, we have observed the effect of midazolam as an adjuvant in patients undergoing infraumbilical surgery. In this prospective, randomized, double blinded, and parallel group and open label study of 90 adult patients aged 18–60 years, of American Society of Anaesthesiologists (ASA) status I and II, scheduled for elective infraumbilical surgery, were randomly allocated in two groups. Each patient in group “B” received hyperbaric bupivacaine 12.5 mg along with 0.4 mL of normal saline in the subarachnoid block, and patients of group “BM” received 12.5 mg hyperbaric bupivacaine along with preservative free midazolam 0.4 mL (2 mg). We found that use of midazolam as adjuvant with the local anesthetic in spinal anaesthesia significantly increases the duration of analgesia (median 320 min versus 220 min) and motor block (median 255 min versus 195 min) but decreases the incidence of postoperative nausea-vomiting (PONV).

Midazolam in Subarachnoid Block: Current Evidence

Midazolam, despite of being the commonest benzodiazepine used in anaesthesia and perioperative care, is a relatively newer addition to the list of adjuvant used in subarachnoid block. Midazolam causes spinally mediated analgesia and the segmental analgesia produced by intrathecal midazolam is mediated by the benzodiazepine-GABA receptor complex. Initial animal studies questioned the safety of intrathecal midazolam in terms of possible neurotoxicity. However subsequent clinical studies also failed to show any neurotoxicity of high dose midazolam even on long-term use. Addition of intrathecal midazolam to bupivacaine significantly improves the duration and quality of spinal anaesthesia and provides prolonged perioperative analgesia without any significant side effects. Clinical studies also reported its safety and efficacy in pregnant women, but some studies also reported mild sedation with intrathecal midazolam. It is also reported to decrease the incidence of PONV. Intrathecal midazolam does not have any clinically significant effect on perioperative hemodynamics.

The effect of adjuvant midazolam compared with fentanyl on the duration of spinal anesthesia with 0.5% bupivacaine in opium abusers

Background

There are a number of adjuvants to be used for local anesthetics in spinal block. The aim of this study was to demonstrate the possible effect of intrathecal midazolam compared with bupivacaine as adjuvants in spinal anesthesia with bupivacaine in chronic opium abuses.

Methods

In a double blind, randomized clinical trial, 90 opium abuser patients undergoing lower limb orthopedic surgery were selected and randomly assigned into 3 groups (30 cases each). The patients received 15 mg plain bupivacaine, or 15 mg bupivacaine plus 25 mcg fentanyl or 15 mg bupivacaine plus 1 mg midazolam, intrathecally.

Results

The duration of anesthesia was much longer in the bupivacaine-midazolam group than the bupivacaine-fentanyl group; both were longer than the plain bupivacaine group (P < 0.05).

Conclusions

Subarachnoid injection of adjuvant midazolam or fentanyl with plain 0.5% bupivacaine in opium abusers in lower limb orthopedic surgery increases the duration of sensory block. Therefore midazolam is more effective than fentanyl in such cases.

Midazolam activates the intrinsic pathway of apoptosis independent of benzodiazepine and death receptor signaling

BACKGROUND AND OBJECTIVES

Midazolam has neurotoxic properties when administered neuraxially in vivo. Furthermore, midazolam induces neurodegeneration in neonatal animal models in combination with other general anesthetics. Therefore, this study focuses on the mechanism of neurotoxicity by midazolam in neuronal and nonneuronal cells. The study aims to evaluate the apoptotic pathway and to investigate the protective effects of the benzodiazepine antagonist flumazenil and the caspase inhibitor N-(2-quinolyl)valyl-aspartyl-(2,6-difluorophenoxy)-methylketone.

METHODS

The apoptosis-inducing effect of preservative-free midazolam on human lymphoma and neuroblastoma cell lines was evaluated using flow cytometric analysis of early apoptotic stages (annexin V/7AAD) and caspase 3 activation. B-cell lymphoma (Bcl2) protein overexpressing and caspase 9-deficient lymphoma cells were used to determine the role of the mitochondrial (intrinsic) pathway. Caspase 8-deficient and Fas-associated protein with death domain (FADD)-deficient cells were used to evaluate the death receptor (extrinsic) pathway. The protective effects of flumazenil and the caspase inhibitor N-(2-quinolyl)valyl-aspartyl-(2,6-difluorophenoxy)-methylketone were investigated in neuroblastoma cells and primary rat neurons using metabolic activity assays (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and immunofluorescence microscopy.

RESULTS

Midazolam induced apoptosis in all investigated cell types in a concentration-dependent manner, indicated by flow cytometry. Bcl2-overexpression and caspase 9 deficiency protected against toxicity, whereas caspase 8 or FADD deficiency had no effect. Pancaspase inhibition had a strong protective effect, whereas flumazenil did not inhibit midazolam-induced apoptosis.

CONCLUSIONS

Midazolam induces apoptosis via activation of the mitochondrial pathway in a concentration-dependent manner. The mechanism of midazolam toxicity switches from caspase-dependent apoptosis to necrosis with increasing concentrations. The induction of apoptosis and necrosis by midazolam is presumably unrelated to GABAA receptor pathway signaling.

Comparative evaluation of intrathecal midazolam and low dose clonidine: efficacy, safety and duration of analgesia. A randomized, double blind, prospective clinical trial

Background:

The study was planned to assess the comparative efficacy, safety and duration of analgesia produced by low-dose clonidine and midazolam when used as adjuvant for spinal anesthesia.

Materials and Methods:

This is a randomized, participant and observer blind, prospective, parallel group clinical trial. Fifty ASA grade I and II patients posted for lower abdominal surgery were randomly allocated into two groups. BC group received spinal clonidine 30 μg and BM group received preservative-free midazolam 2 mg with 15 mg hyperbaric bupivacaine. Postoperative analgesia, analgesic requirement in 24 hours, onset and duration of block, hemodynamic stability and adverse effects were observed (P<0.05 – considered significant, P<0.01 considered highly significant).

Results:

The duration of postoperative analgesia was prolonged in BM group (391.64 ± 132.98 min) than BC group (296.60 ± 52.77 min) (P<0.01). The mean verbal rating pain score was significantly less in BM group than BC group (P<0.01). The number of analgesic doses in 24 hours were significantly less in BM group (P<0.05). Nine patients (36%) in BC group required additional analgesia as against none in BM group (P<0.01). The onset of sensory block and peak sensory level was significantly earlier in BM group as compared to BC group. Duration of sensory block was longer in BM group (P<0.05). Subjects in BC group(36%) had bradycardia as compared to none in BM group (P<0.01). Hypotension was observed in 44% patients in BC group as against 16% in BM group (P<0.05).

Conclusion:

Postoperative analgesia with clonidine is short lived with some bradycardia. Intrathecal midazolam provides superior analgesia without clinically relevant adverse effects.

Effect of intrathecal midazolam in the severity of pain in cesarean section: a randomized controlled trail

BACKGROUND

The benzodiazepines are used primarily for anxiolysis, amnesia and sedation. However, recent investigations have shown that some forms of this group of drugs have also direct effect on pain. This study aims to determine the effect of midazolam in reducing the severity of pain in women scheduled for elective cesarean section.

METHODS

In a prospective, double blind randomized controlled trial, two groups parallel study, was conducted in Imam Reza/Moatazedi Hospital, an affiliate of Kermanshah University of Medical Sciences. Parturient women who met study inclusion criteria were consecutively assigned into either experimental (n=62) or control groups (n=62). Women in the experimental group received bupivacaine (10 mg) plus intrathecal midazolam (2 mg/ml) (BM) and those in the control group received bupivacaine plus normal saline (BNS). The outcome pain severity was measured by Verbal Numerical Rating Scale.

RESULTS

In comparison with the BNS group, mothers in the BM group reported a significant relief in pain (15 min and 120 min) after the surgery. There were no significant differences between the groups regarding the intensity of pain 5, 30, 60 and 240 min after the surgery. The average time until the first dose of additional analgesic, per mother's request was 142.18±55.19 min in the BNS vs 178.06±77.33 min in the BM group.

CONCLUSION

Combination of bupivacaine plus intrathecal midazolam was an effective anesthetic technique to provide improvement in pain. The onset of sedation was faster in the BM group compared with the BNS group. The duration of effective analgesia, and the time for regression of sensory analgesia was the same in both groups in our study. However, incidence of nausea and vomiting was higher in the experimental group.

Evidence-based management of pain after haemorrhoidectomy surgery

BACKGROUND

Haemorrhoidectomy is associated with intense postoperative pain, but optimal evidence-based pain therapy has not been described. The aim of this systematic review was to evaluate the available literature on the management of pain after haemorrhoidal surgery.

METHODS

Randomized studies published in the English language from 1966 to June 2006, assessing analgesic and anaesthetic interventions in adult haemorrhoidal surgery, and reporting pain scores, were retrieved from the Embase and MEDLINE databases.

RESULTS

Of the 207 randomized studies identified, 106 met the inclusion criteria, with mixed methodological quality. Of these, 41 studies evaluating surgical and alternative interventions were excluded. Quantitative analyses were not performed, as there were limited numbers of trials with a sufficiently homogeneous design.

CONCLUSION

Local anaesthetic infiltration, either as a sole technique or as an adjunct to general or regional anaesthesia, and combinations of analgesics (non-steroidal anti-inflammatory drugs, paracetamol and opiates) are recommended. If appropriate, a stapled operation may be preferable.

Chloride regulation in the pain pathway

Melzack and Wall's Gate Control Theory of Pain laid the theoretical groundwork for a role of spinal inhibition in endogenous pain control. While the Gate Control Theory was based on the notion that spinal inhibition is dynamically regulated, mechanisms underlying the regulation of inhibition have turned out to be far more complex than Melzack and Wall could have ever imagined. Recent evidence indicates that an exquisitely sensitive form of regulation involves changes in anion equilibrium potential (E(anion)), which subsequently impacts fast synaptic inhibition mediated by GABA(A), and to a lesser extent, glycine receptor activation, the prototypic ligand gated anion channels. The cation-chloride co-transporters (in particular NKCC1 and KCC2) have emerged as proteins that play a critical role in the dynamic regulation of E(anion) which in turn appears to play a critical role in hyperalgesia and allodynia following peripheral inflammation or nerve injury. This review summarizes the current state of knowledge in this area with particular attention to how such findings relate to endogenous mechanisms of hyperalgesia and allodynia and potential applications for therapeutics based on modulation of intracellular Cl(-) gradients or pharmacological interventions targeting GABA(A) receptors.

Complexation study of midazolam hydrochloride with beta-cyclodextrin: NMR spectroscopic study in solution

(1)H NMR spectroscopic study of midazolam hydrochloride (MDL), beta-cyclodextrin (beta-CD) and their mixtures confirmed the formation of beta-CD-MDL inclusion complex in aqueous solution. The stoichiometry of the complexes was determined by Scott's method to be 1:1, and the association constant (K(a)) was calculated to be 108 M(-1). It was confirmed on the basis of 2D ROESY spectral data that only a fluorine-substituted aromatic ring acted as guest in complexation. Most of the aromatic signals of MDL exhibited induced shift changes as well as splitting, in the presence of beta-CD, indicating chiral differentiation of MDL by beta-CD.

Use of Intrathecal Midazolam to Improve Perioperative Analgesia: A Meta-Analysis

Intrathecal midazolam binds with gamma aminobutyric acid-A receptors in the spinal cord leading to an analgesic effect. Clinical studies suggested that intrathecal midazolam may also reduce nausea and vomiting when used as an adjunct to other spinal medications. However, the potential neurotoxic effect of intrathecal midazolam remains a concern. This meta-analysis aims to evaluate the effectiveness and side-effects of intrathecal midazolam in the perioperative and peripartum settings. Thirteen randomised controlled studies from MEDLINE (from 1966 to July 1 2007), EMBASE and Cochrane Controlled Trials Register databases, involving a total of 672 patients, were considered. Volunteer, animal and chronic pain studies were excluded. Adding intrathecal midazolam to other spinal medications reduced the incidence of nausea and vomiting (odds ratio 0.50, 95% confidence interval [CI] 0.27 to 0.90, P=0.02; I 2 =4%) and delayed the time to request for rescue analgesia (weighted-mean-difference=98.7 min, 95% CI: 76.1 to 121.4, P <0.00001; I=98.5%). Intrathecal midazolam did not affect the duration of motor blockade (weighted-mean-difference =25.1 min, 95% CI -7.6 to 57.8, P=0.13, I 2 =94.8%). The incidence of neurological symptoms after intrathecal midazolam was uncommon (1.8%) and did not differ from placebo (odds ratio 1.20, 95% CI 0.22 to 6.68, P=0.84). Based on the limited data available, intrathecal midazolam appears to improve perioperative analgesia and reduce nausea and vomiting during caesarean delivery. A multicentre registry or large randomised controlled study with a prolonged follow-up period would be useful to confirm the clinical safety of intrathecal midazolam.

Combination of low doses of intrathecal ketamine and midazolam with bupivacaine improves postoperative analgesia in orthopaedic surgery

BACKGROUND

Intrathecal ketamine produces a short period of analgesia with stable haemodynamics. Midazolam with bupivacaine prolongs the duration of analgesia when administered intrathecally but does not prevent hypotension. The objective of this study was to assess the effect of a combination of intrathecal bupivacaine, ketamine and midazolam on the duration of analgesia and haemodynamic parameters.

METHODS

A prospective, randomized, double-blind study was carried out in 60 ASA I and II patients undergoing lower limb surgery under spinal anaesthesia. Patients were divided into three groups of 20 each. Patients in all the three groups received 3 mL of hyperbaric bupivacaine (0.5%) intrathecally. In addition, patients in Groups II and III received intrathecal ketamine (0.1 mg kg-1) and the same dose of ketamine along with midazolam (0.02 mg kg-1), respectively. All patients were evaluated for block characteristics, duration of pain-free period, total rescue analgesic requirement in the 24-h postoperative period, total dose of mephenteramine to treat hypotension and any central or neurological complication.

RESULTS

No patients in Group II required mephenteramine while 40% of patients in Group I and 10% in Group III required mephenteramine to maintain blood pressure after spinal anaesthesia. The mean +/- standard deviation duration of pain-free period was 331.5 +/- 89.9, 369.7 +/- 124.2 and 730.5 +/- 81.5 min in Group I, II and III, respectively. The pain-free interval was significantly greater in Group III compared to Groups I and II (P < 0.001). No patient had any complications.

CONCLUSION

A low dose of midazolam and ketamine with bupivacaine intrathecally results in prolonged analgesia and less haemodynamic fluctuations. However, the safety of this combination needs to be proved before its use in clinical practice.

Improved postoperative analgesia with coadministration of preoperative epidural ketamine and midazolam

STUDY OBJECTIVE

To assess postoperative pain regulation and pharmacokinetic effects of preoperative administration of ketamine and midazolam.

DESIGN

Double-blind, randomized clinical study.

SETTING

University hospital.

PATIENTS

46 ASA physical status I and II patients (age, 26-58 yrs), scheduled for gastrectomy.

INTERVENTIONS

Patients were randomly assigned to three treatment groups: a preoperative epidural injection of 10 mL (1) ketamine (0.5 mg/kg) solution (Ket group); (2) ketamine (0.5 mg/kg) plus midazolam (0.05 mg/kg) solution (KM group); or (3) normal saline solution (Ctr group).

MEASUREMENTS

Analgesic effects were evaluated by Visual Analog Scale (VAS) pain scores at rest, time to first request for analgesic (TFA), and morphine consumption during the initial postoperative time of 48 hours. Plasma concentration of ketamine in the Ket group and the KM group was measured by high-performance liquid chromatography, and the elimination half-life of ketamine was calculated.

MAIN RESULTS

Compared with the Ctr group, the Ket and KM groups had lower VAS pain scores, longer TFA, and lower morphine consumption. The KM group had the longest TFA and the lowest morphine consumption of the three groups. The KM group also had higher plasma concentrations of ketamine 90 to 240 minutes after injection, and a longer elimination half-life of ketamine, than did the Ket group.

CONCLUSIONS

Preoperative epidural coadministration of a low dose of ketamine with midazolam is more effective in relieving postoperative pain than using ketamine alone. In addition, epidural midazolam prolongs the elimination of ketamine.