Association between bispectral index and age and use of sedative drugs in high spinal anaesthesia

OBJECTIVES

A prospective, randomized, double-blind study using bispectral index values to objectively quantify the sedative effect of high spinal anaesthesia in patients stratified according to age, and to determine whether sedative drugs are associated with additional adverse respiratory and haemodynamic effects in older patients.

METHODS

Patients who were electively scheduled for lower limb or abdominal surgery were recruited and allocated into one of three groups according to their age and whether midazolam and fentanyl were used: younger (20-40 years); and older (61-80 years) with or without midazolam and fentanyl intravenous infusion.

RESULTS

The study recruited a total of 90 patients (n = 30 per group). Intraoperative bispectral index values were significantly lower than preoperative values in all groups. Patients in the older age group had significantly lower intraoperative bispectral index values than younger patients. Older patients were significantly more likely to experience respiratory depression (arterial oxyhaemoglobin saturation <90%) than younger patients.

CONCLUSIONS

The sedative effect of high spinal anaesthesia is greater in older patients than in younger patients, with an increase in respiratory instability.

A review of the practice of sedation with inhalational anaesthetics in the intensive care unit with the AnaConDa(®) device

The intensive care unit (ICU) environment is often perceived to be hostile and frightening by patients due to unfamiliar surroundings coupled with presence of numerous personnel, monitors and other equipments as well as a loss of perception of time. Mechanical ventilation and multiple painful procedures that often need to be carried out in these critically ill patients add to their overall anxiety. Sedation is therefore required not only to allay the stress and anxiety, but also to allow for mechanical ventilation and other invasive therapeutic and diagnostic procedures to be performed. The conventional intravenous sedative agents used in ICUs suffer from problems of over sedation, tachyphylaxis, drug accumulation, organ specific elimination and often lead to patient agitation on withdrawal. All this tend to prolong the ventilatory as well as ICU and hospital discharge time, which increase the risk for infection and add to the overall increase in morbidity, mortality and hospital costs. In 2005, the anaesthetic conserving device (AnaConDa(®)) was marketed for ICU sedation with volatile anaesthetic agents. A number of trials have shown the effectiveness of using volatile anaesthetic agents for ICU sedation with the AnaConDa device. Compared with intravenous sedatives, use of volatile anaesthetic agents have resulted in shorter wake up and extubation time, lesser duration of mechanical ventilation and faster discharge from hospitals. This review shall focus on the benefits, technical pre-requisites and status of sedation with volatile anaesthetic agents in ICUs with the AnaConDa(®) device.

Anesthetic drug development: Novel drugs and new approaches

The ideal sedative–hypnotic drug would be a rapidly titratable intravenous agent with a high therapeutic index and minimal side effects. The current efforts to develop such agents are primarily focused on modifying the structures of existing drugs to improve their pharmacodynamic and pharmacokinetic properties. Drugs currently under development using this rational design approach include analogues of midazolam, propofol, and etomidate, such as remimazolam, PF0713, and cyclopropyl methoxycarbonyl-etomidate (MOC-etomidate), respectively. An alternative approach involves the rapid screening of large libraries of molecules for activity in structural or phenotypic assays that approximate anesthetic and target receptor interactions. Such high-throughput screening offers the potential for identifying completely novel classes of drugs. Anesthetic drug development is experiencing a resurgence of interest because there are new demands on our clinical practice that can be met, at least in part, with better agents. The goal of this review is to provide the reader with a glimpse of the novel anesthetic drugs and new developmental approaches that lie on the horizon.

A prospective, randomized, double blind and placebo-control study comparing the additive effect of oral midazolam and clonidine for postoperative nausea and vomiting prophylaxis in granisetron premedicated patients undergoing laparoscopic cholecystecomy

Background:

Reduction of postoperative nausea and vomiting (PONV) continues to be a major challenge in perioperative care in spite of introduction of newer antiemetics with better efficacy and safety profiles. Therefore, we evaluated the additive effect of oral midazolam and clonidine for PONV prophylaxis in granisetron premedicated patients undergoing laparoscopic cholecystectomy.

Materials and Methods:

In a prospective, randomized fashion, 120 selected cases were randomized into three groups: I, II or III to receive a tablet of midazolam (15 mg, n = 36), clonidine (150 mcg, n = 40), or glucose as placebo (5 g, n = 44) orally, 1 h before anesthesia. Occurrence of PONV along with need for rescue antiemetic during the first postoperative day was compared between groups as a primary outcome.

Results:

Episodes of PONV reduced significantly in Group II (15%) as compared to group I and III (22.2%, 59%) at various time points during the period of observation (P = 0.002). Need for rescue antiemetic was significantly lower in group I (13.88%) and II (5%) as compared to group III (52.27%, P < 0.001).

Conclusion:

Oral clonidine is better adjuvant for PONV prophylaxis, as compared to midazolam, in granisetron premedicated patients undergoing laparoscopic cholecystectomy.

Pharmacological treatment of neonatal seizures: a systematic review

Pharmacologic treatment options for neonatal seizures have expanded over the past 2 decades, and there is no consensus on optimal treatment strategy. We systematically reviewed the published literature to determine which medication(s) are most effective for treating neonatal seizures, by retrieving trials and observational investigations via PubMed (through August 2011) that focused on pharmacological seizure treatment of neonates (≤ 28 days old) and utilized continuous or amplitude-integrated EEG to confirm seizure diagnosis and cessation. Our search identified 557 initial articles and 14 additional studies after reference reviews, with 16 meeting inclusion criteria. Of these, 2 were randomized trials and only 3 additional investigations included comparison groups. We found limited evidence regarding the best pharmacologic treatment for neonatal seizures, but were able to devise a treatment algorithm from available data. These findings have the potential to serve as a clinical reference and to inform the design of comparative effectiveness investigations for neonatal antiepileptics.

Comparison of sedation effectiveness of remifentanil-dexmedetomidine and remifentanil-midazolam combinations and their effects on postoperative cognitive functions in cystoscopies: A randomized clinical trial

BACKGROUND

The aim of the study is to compare the effects of remifentanil/dexmedetomidine and remifentanil/midazolam combinations in monitored anesthesia care (MAC) during cystoscopies.

MATERIALS AND METHODS

Forty patients who received remifentanil infusion of 0.05 μg kg(-1) min(-1) for cytoscopy procedure were randomized into two groups: Either dexmedetomidine 1 mg kg(-1) (Group D) or midazolam 0.2 mg kg(-1) h(-1) (Group M) was administered intravenously for the first 10 min. Subsequently, anesthesia was maintained by using the bispectral index as a continuous infusion of dexmedetomidine (0.2-0.7 μg kg(-1) h(-1)) or midazolam (0.05-0.15 μg kg(-1) h(-1)). Heart rate, mean arterial pressure, mini-mental state examination findings, levels of sedation andanalgesia, and the patient's and surgeon's satisfaction were recorded.

RESULTS

Successful sedation and analgesia were achieved in all the patients. We were able to reach the target sedation level faster in Group D (P<0.0001). In Group D, the cognitive functions were less affected than in Group M (P<0.0001). Patient's and surgeon's satisfaction were significantly higher in Group D.

CONCLUSION

The targeted sedation levels were achieved in a shorter period with dexmedetomidine-remifentanil compared to midazolam-remifentanil. The dexmedetomidine-remifentanil combination was observed to affect the cognitive functions less than midazolam-remifentanil did with shorter recovery times. Besides, patient's and surgeon's satisfaction rates were superior with dexmedetomidine-remifentanil. It was concluded that dexmedetomidine-remifentanil may be a combination of choice for monitored anesthesia care applications in outpatient surgical procedures of short duration.

Effect of a herbal extract containing curcumin and piperine on midazolam, flurbiprofen and paracetamol (acetaminophen) pharmacokinetics in healthy volunteers

AIMS

Turmeric extract derived curcuminoids (curcumin, demethoxycurcumin and bisdemethoxycurcumin) are currently being evaluated for the treatment of cancer and Alzheimer's dementia. Previous in vitro studies indicate that curcuminoids and piperine (a black pepper derivative that enhances curcuminoid bioavailability) could inhibit human CYP3A, CYP2C9, UGT and SULT dependent drug metabolism. The aim of this study was to determine whether a commercially available curcuminoid/piperine extract alters the pharmacokinetic disposition of probe drugs for these enzymes in human volunteers.

METHODS

A randomized placebo-controlled six way crossover study was conducted in eight healthy volunteers. A standardized curcuminoid/piperine preparation (4 g curcuminoids plus 24 mg piperine) or matched placebo was given orally four times over 2 days before oral administration of midazolam (CYP3A probe), flurbiprofen (CYP2C9 probe) or paracetamol (acetaminophen) (dual UGT and SULT probe). Plasma and urine concentrations of drugs, metabolites and herbals were measured by HPLC. Subject sedation and electroencephalograph effects were also measured following midazolam dosing.

RESULTS

Compared with placebo, the curcuminoid/piperine treatment produced no meaningful changes in plasma C(max), AUC, clearance, elimination half-life or metabolite levels of midazolam, flurbiprofen or paracetamol (α = 0.05, paired t-tests). There was also no effect of curcuminoid/piperine treatment on the pharmacodynamics of midazolam. Although curcuminoid and piperine concentrations were readily measured in plasma following glucuronidase/sulfatase treatment, unconjugated concentrations were consistently below the assay thresholds (0.05-0.08 μM and 0.6 μM, respectively).

CONCLUSION

The results indicate that short term use of this piperine-enhanced curcuminoid preparation is unlikely to result in a clinically significant interaction involving CYP3A, CYP2C9 or the paracetamol conjugation enzymes.

Continuous intravenous anaesthesia with sufentanil and midazolam in medetomidine premedicated New Zealand White rabbits

BACKGROUND

Anaesthesia in rabbits is associated with a high mortality rate, compared to that in cats and dogs. Total intravenous anaesthesia (TIVA) with drugs that provide cardiovascular stability and are rapidly metabolised could be of benefit for use in rabbits. The aim was to evaluate cardiorespiratory effects of TIVA with sufentanil-midazolam in eight New Zealand White rabbits. Subcutaneous premedication with medetomidine (0.1 mg/kg BW) was followed by IV administration of a mixture of 2.5 μg/mL sufentanil and 0.45 mg/mL midazolam at a rate of 0.3 mL/kg BW/h for anaesthetic induction. Additionally, intravenous boluses of 0.1 mL of the mixture were administered every 20 s until the righting reflex was lost. Following endotracheal intubation, anaesthesia was maintained for 60 min with an infusion rate adjusted to supress the pedal withdrawal reflex. Air and oxygen (1:2) were delivered at 3 L/min. Physiological variables were recorded before induction and at predefined time points during and after anaesthesia.

RESULTS

Righting and pedal withdrawal reflexes were lost within 3 and 5 min, respectively. Doses of sufentanil and midazolam were 0.48 μg/kg BW and 0.09 mg/kg BW for induction, and 0.72 μg/kg BW/h and 0.13 mg/kg BW/h for maintenance. Apnoea occurred in two rabbits. Induction of anaesthesia caused a significant increase in heart rate, cardiac output and arterial CO2 partial pressure and a decrease in mean arterial pressure, respiratory rate and pH. Mean time from stopping the infusion to endotracheal extubation was 5 min, and to return of the righting reflex 7 min. Anaesthesia was characterized by induction and recovery without excitation, with muscle relaxation, and absence of the pedal withdrawal reflex.

CONCLUSIONS

TIVA with sufentanil-midazolam provided smooth induction and recovery of anaesthesia in rabbits but with marked hypotension and respiratory depression, requiring mechanical ventilation. Further evaluation is needed to establish if the protocol is useful for rabbits undergoing surgery.

Inhibition of cancer cell proliferation by midazolam by targeting transient receptor potential melastatin 7

Transient receptor potential melastatin 7 (TRPM7), a Ca²⁺-permeable channel, has been demonstrated to be present in cancer cells and involved in their growth and proliferation. The present study used midazolam, a benzodiazepine class anesthesic, to pharmacologically intervene in the expression of TRPM7 and to inhibit cancer cell proliferation. Midazolam significantly inhibited the growth and proliferation of FaDu human hypopharyngeal squamous cell carcinoma cells, concurring with the induction of G₀/G₁ cell cycle arrest and blockage of Rb activation. Central-type and peripheral-type benzodiazepine receptor antagonists did not abrogate proliferation inhibition by midazolam, while the specific TRPM7 agonist bradykinin reversed this effect. In addition, other benzodiazepines, diazepam and clonazepam also exhibited anti-proliferative activities. The inhibitory activity on cancer cell growth and proliferation, combined with the TRPM-dependent mechanism, reveals the anticancer potential of midazolam as a TRPM7 inhibitor and supports the suggestion that TRPM7 is a valuable target for pharmaceutical intervention.

Anesthetic effects of a mixture of medetomidine, midazolam and butorphanol in two strains of mice

The combination of ketamine and xylazine is a widely used anesthetic for laboratory animals. However, due to an abuse problem in Japan, ketamine has been specified as a narcotic since 2007. Instead of using ketamine, Kawai et al. reported an injectable formula with an equivalent effect to the mixture of ketamine and xylazine [11]. The mixture of 0.3 mg/kg body weight (b.w.) medetomidine (Med.), 4.0 mg/kg b.w. midazoram (Mid.), and 5.0 mg/kg b.w. butorphanol (But.) produced an anesthetic duration of around 40 min in outbred ICR mice. However, the anesthetic effect of the mixture for inbred mice strains remains unknown. Therefore, we examined anesthetic effects of the mixture of Med., Mid., and But. in the BALB/c and C57BL/6J strains. After intraperitoneal injection into mice, right front paw, left hind paw, and tail pinch reflexes as well as corneal and righting reflexes were observed. Every 5 min, we scored each reflex category as 0 for reaction or 1 for no reaction. As long as the total score was at least 4 out of 5, we considered the mixture as putting a mouse in a surgical anesthetic state. The mixture produced an anesthetic duration of more than 45 min in both strains of mice. These results indicate that the mixture of Med., Mid., and But. can be a useful and effective anesthesia for the BALB/c and C57BL/6J strains of inbred mice as well as outbred ICR mice.

Prophylactic administration of haloperidol plus midazolam reduces postoperative nausea and vomiting better than using each drug alone in patients undergoing middle ear surgery

Aims:

The efficacy of using midazolam or haloperidol for prevention of postoperative nausea and vomiting (PONV) has been investigated before. The main object of the present study was to evaluate the anti-emetic effects of combining administration of intravenous haloperidol with intravenous midazolam on PONV in patients underwent middle ear surgery in comparison with using each drug alone.

Methods:

Study design was randomized, double-blind, placebo-controlled. 80 patients, aged 18-60 years, scheduled for middle ear surgery in Kashani Hospital Medical Center under general anesthesia were enrolled in this randomized, double-blind, placebo-controlled study. Patients were divided into 4 groups of 20 each and received haloperidol 2 mg i.v. (Group H); midazolam 2 mg i.v. (Group M); haloperidol 2 mg plus midazolam 2 mg i.v. (Group HM); saline i.v. (Group C). The incidences of PONV and complete response were evaluated at 0-2 hours after arrival to the PACU and 2-24 hours after arrival to the ward in 4 groups.

Results:

Patients in group HM had significantly lower incidence of PONV compared with groups H, M, and C throughout 0-24 h (P<00.5). The HM group had the lowest incidence of PONV (0-2, 2-24, and 0-24 h) and the highest incidence of complete response. Postoperative anti-emetic requirement was significantly less in group HM compared with group M or H (P<0.05).

Conclusion:

Combine administration of haloperidol 2 mg plus midazolam 2 mg significantly reduced PONV better than using each drug alone in patients underwent middle ear surgery under general anesthesia.

Preanesthetic medication in children: A comparison of intranasal dexmedetomidine versus oral midazolam

Background:

Relieving preoperative anxiety is an important concern for the pediatric anesthesiologist. Midazolam has become the most frequently used premedication in children. However, new drugs such as the α₂ -agonists have emerged as alternatives for premedication in pediatric anesthesia.

Methods:

One hundred and twenty children scheduled for adenotonsillectomy were enrolled in this prospective, double-blind, randomized study. The children were divided into two equal groups to receive either intranasal dexmedetomidine 1 μg/kg (group D), or oral midazolam 0.5 mg/kg (group M) at approximately 60 and 30 mins, respectively, before induction of anesthesia. Preoperative sedative effects, anxiety level changes, and the ease of child-parent separation were assessed. Also, the recovery profile and postoperative analgesic properties were assessed.

Results:

Children premedicated with intranasal dexmedetomidine achieved significantly lower sedation levels (P=0.042), lower anxiety levels (P=0.036), and easier child-parent separation (P=0.029) than children who received oral midazolam at the time of transferring the patients to the operating room. Postoperatively, the time to achieve an Aldrete score of 10 was similar in both the groups (P=0.067). Also, the number of children who required fentanyl as rescue analgesia medication was significantly less (P=0.027) in the dexmedetomidine group.

Conclusion:

Intranasal dexmedetomidine appears to be a better choice for preanesthetic medication than oral midazolam in our study. Dexmedetomidine was associated with lower sedation levels, lower anxiety levels, and easier child-parent separation at the time of transferring patients to the operating room than children who received oral midazolam. Moreover, intranasal dexmedetomidine has better analgesic property than oral midazolam with discharge time from postanesthetic care unit similar to oral midazolam.

Postoperative nausea and vomiting after myringoplasty under continuous sedation using midazolam with or without remifentanil

PURPOSE

This prospective study evaluated the effects of continuous sedation using midazolam, with or without remifentanil, on postoperative nausea and vomiting (PONV) in patients undergoing myringoplasty.

MATERIALS AND METHODS

Sixty patients undergoing myringoplasty were sedated with midazolam in the presence of remifentanil (group MR), or after saline injection instead of remifentanil (group M).

RESULTS

Three patients (10%) in group M complained of nausea; two vomited. Four patients (13%) in group MR complained of nausea and vomited within 24 h after surgery. Rescue drugs were given to the six patients who vomited. No significant difference was detected between the two groups regarding the incidence or severity of nausea, incidence of vomiting, or need for rescue drugs.

CONCLUSION

Midazolam-based continuous sedation can reduce PONV after myringoplasty. Compared with midazolam alone, midazolam with remifentanil produced no difference in the incidence or severity of nausea, incidence of vomiting, or need for rescue drugs.

Midazolam-induced acute dystonia reversed by diazepam

Midazolam can induce acute dystonia in childhood. We report the development of acute dystonia in a 6-year-old girl after receiving midazolam as a sedative. Dystonic contractions persisted despite flumazenil and biperiden lactate injections and the patient was treated with diazepam. Acute dystonia was rapidly abolished after the administration of diazepam intravenously. Diazepam may be an effective treatment option in patients who are unresponsive to flumazenil.

On disruption of fear memory by reconsolidation blockade: evidence from cannabidiol treatment

The search for reconsolidation blockers may uncover clinically relevant drugs for disrupting memories of significant stressful life experiences, such as those underlying the posttraumatic stress disorder. Considering the safety of systemically administered cannabidiol (CBD), the major non-psychotomimetic component of Cannabis sativa, to animals and humans, the present study sought to investigate whether and how this phytocannabinoid (3-30 mg/kg intraperitoneally; i.p.) could mitigate an established memory, by blockade of its reconsolidation, evaluated in a contextual fear-conditioning paradigm in rats. We report that CBD is able to disrupt 1- and 7-days-old memories when administered immediately, but not 6 h, after their retrieval for 3 min, with the dose of 10 mg/kg being the most effective. This effect persists in either case for at least 1 week, but is prevented when memory reactivation was omitted, or when the cannabinoid type-1 receptors were antagonized selectively with AM251 (1.0 mg/kg). Pretreatment with the serotonin type-1A receptor antagonist WAY100635, however, failed to block CBD effects. These results highlight that recent and older fear memories are equally vulnerable to disruption induced by CBD through reconsolidation blockade, with a consequent long-lasting relief in contextual fear-induced freezing. Importantly, this CBD effect is dependent on memory reactivation, restricted to time window of <6 h, and is possibly dependent on cannabinoid type-1 receptor-mediated signaling mechanisms. We also observed that the fear memories disrupted by CBD treatment do not show reinstatement or spontaneous recovery over 22 days. These findings support the view that reconsolidation blockade, rather than facilitated extinction, accounts for the aforementioned CBD results in our experimental conditions.

Nasal and buccal treatment of midazolam in epileptic seizures in pediatrics

Acute seizure and status epilepticus constitute major medical emergencies in children. Four to six percent of children will have at least one seizure in the first 16 years of life. Status epilepticus is a common neurological emergency in childhood and is associated with significant morbidity and mortality. The early application of antiepileptic treatment is very important. Because early treatment prevents the status epilepticus formation and shortens the duration of seizure activity. For this reason administration of anticonvulsant therapy in the prehospital setting is very important. Seizures generally begin outside the hospital, and thus parents and caregivers need simple, safe and effective treatment options to ensure early intervention. The only special preparation used for this purpose is rectal diazepam but has some disadvantages. Midazolam is a safe, short-acting benzodiazepin. It is suitable to use oral, buccal, nasal, im and iv routes. This provides a wide area for clinical applications. Recently there are many clinical studies about the usage of nasal and buccal midazolam for treatment of pediatric epileptic seizures. The nasal and buccal applications in pediatric seizures are very practical and effective. Parents and caregivers can apply easily outside the hospital.

Effect of midazolam on the proliferation of neural stem cells isolated from rat hippocampus

In many recent studies, the inhibitory transmitter gamma-aminobutyric acid has been shown to modulate the proliferation, differentiation and survival of neural stem cells. Most general anesthetics are partial or allosteric gamma-aminobutyric acid A receptor agonists, suggesting that general anesthetics could alter the behavior of neural stem cells. The neuroprotective efficacy of general anesthetics has been recognized for decades, but their effects on the proliferation of neural stem cells have received little attention. This study investigated the potential effect of midazolam, an extensively used general anesthetic and allosteric gamma-aminobutyric acid A receptor agonist, on the proliferation of neural stem cells in vitro and preliminarily explored the underlying mechanism. The proliferation of neural stem cells was tested using both Cell Counting Kit 8 and bromodeoxyuridine incorporation experiments. Cell distribution analysis was performed to describe changes in the cell cycle distribution in response to midazolam. Calcium imaging was employed to explore the molecular signaling pathways activated by midazolam. Midazolam (30–90 μM) decreased the proliferation of neural stem cells in vitro. Pretreatment with the gamma-aminobutyric acid A receptor antagonist bicuculline or Na-K-2Cl cotransport inhibitor furosemide partially rescued this inhibition. In addition, midazolam triggered a calcium influx into neural stem cells. The suppressive effect of midazolam on the proliferation of neural stem cells can be partly attributed to the activation of gamma-aminobutyric acid A receptor. The calcium influx triggered by midazolam may be a trigger factor leading to further downstream events.

Influence of Panax ginseng on cytochrome P450 (CYP)3A and P-glycoprotein (P-gp) activity in healthy participants

A number of herbal preparations have been shown to interact with prescription medications secondary to modulation of cytochrome P450 (CYP) and/or P-glycoprotein (P-gp). The purpose of this study was to determine the influence of Panax ginseng on CYP3A and P-gp function using the probe substrates midazolam and fexofenadine, respectively. Twelve healthy participants (8 men) completed this open-label, single-sequence pharmacokinetic study. Healthy volunteers received single oral doses of midazolam 8 mg and fexofenadine 120 mg, before and after 28 days of P ginseng 500 mg twice daily. Midazolam and fexofenadine pharmacokinetic parameter values were calculated and compared before and after P ginseng administration. Geometric mean ratios (postginseng/preginseng) for midazolam area under the concentration-time curve from zero to infinity (AUC(0-∞)), half-life (t(1/2)), and maximum concentration (C(max)) were significantly reduced at 0.66 (0.55-0.78), 0.71 (0.53-0.90), and 0.74 (0.56-0.93), respectively. Conversely, fexofenadine pharmacokinetics were unaltered by P ginseng administration. Based on these results, P ginseng appeared to induce CYP3A activity in the liver and possibly the gastrointestinal tract. Patients taking P ginseng in combination with CYP3A substrates with narrow therapeutic ranges should be monitored closely for adequate therapeutic response to the substrate medication.

Development, implementation, and evaluation of an institutional daily awakening and spontaneous breathing trial protocol: a quality improvement project

INTRODUCTION

While one controlled trial found that a daily awakening and spontaneous breathing trial (DA-SBT) decreases time on mechanical ventilation (MV), there is a paucity of real-world data surrounding the development, implementation, and impact of DA-SBT protocols. We describe a multidisciplinary process improvement effort in 2, 10-bed medical intensive care units (MICUs) at a 330-bed academic medical center that focused on the development, implementation, and evaluation of a new DA-SBT protocol.

METHODS

A DA-SBT protocol, developed using results from a nursing survey literature and available institutional resources, was implemented after extensive clinician education and institution of quality reminders to boost use. Postprotocol compliance was evaluated. Use of sedation, DA and SBT practices, and clinical outcomes were retrospectively compared between the before and after DA-SBT protocol groups (ie, consecutive MICU patients requiring a continuously infused sedative [CIS] ≥24 hours).

RESULTS

In the after group (n = 32), the DA and SBT compliances were 44% and 84%, respectively. Compared with the before group (n = 33), after group patients received CIS on fewer days of MV (100% vs 67%, P = .003) and had their CIS down-titrated by ≥25% on more days of CIS (40% vs 71%, P = .006). Neither total CIS dose (P = .49), total MV days (P = .75), days of MV where a SBT occurred (P = .38), nor episodes of self-extubation (15% vs 6%, P = .43) differed between the 2 groups.

CONCLUSION

Despite the implementation of a DA-SBT protocol that was individualized to clinician preferences and institutional resources and accompanied by substantial education and reminders for use, compliance to the DA component of this protocol was low and duration of MV remained unchanged. Additional quality improvement strategies are needed to overcome barriers to DA-SBT protocol use that may not exist in controlled clinical trials.

Comparing the preventive effect of midazolam and midazolam-dexamethasone on postoperative nausea and vomiting in elective middle ear surgery

Background:

Nausea and vomiting are common postoperative complications with incidence of 20–80% depends on the surgery type, anesthetic drugs, age, sex, etc. This complication may lead to patient discomfort, intraocular, and intracerebral pressures increase, sutures rupture, esophageal injury, and rarely death. Many studies reported that midazolam and dexamethasone alone can decrease postoperative nausea and vomiting (PONV), but their combination has never been studied yet. The aim of this study was to compare the effect of midazolam and midazolam-dexamethasone on PONV after middle ear surgery.

Materials and Methods:

66 ASA I and II patients aged 15–65 year scheduled for elective middle ear surgery under general anesthesia randomly divided into two groups. Immediately after induction of the anesthesia group one (M) received midazolam 0.075 mg/kg and group two (M+D) received combination of midazolam (0.075 mg/kg) plus dexamethasone (0.05 mg/kg). Then the severity of nausea was measured by visual analog scales 0–10 (VAS) in recovery room at 6, 12, and 24 h after surgery. Metoclopramid (0.1 mg/kg) was administrated I.V. slowly if nausea score was above 3 or patient had vomiting. The postoperative need for antiemetics and the duration of stay in recovery room were recorded. Values of P<0.05 were considered statistically significant.

Results:

There were no significant differences in age, gender, and weight between the two groups. There was no significant difference in the mean nausea scores between two groups except after 12 h postoperatively (1.39 ± 3.19 in M group vs. 0.42 ± 1.71 in M+D group). The mean vomiting frequency was significantly less in midazolam-dexamethasone group in the recovery room (0.9 ± 0.29 vs. 0 ± 0) and at 6–12 h (1.09 ± 2.41 vs. 0.3 ± 0.8), and 12–24 h (0.42 ± 1.32 vs. 0.03 ± 0.17) postoperatively. During the first 24 h postoperatively, the metoclopramid consumption was significantly less in combination therapy (6.48 ± 9.54) than in the midazolam group (12.9 ± 23.44) (Value<0.5).

Conclusion:

The combination of midazolam-dexametazone is more effective than midazolam alone in prevention of postoperative vomiting after middle ear surgery. Therefore, we recommend combination therapy for patients who are prone to PONV.

Mild hypothermia decreases fentanyl and midazolam steady-state clearance in a rat model of cardiac arrest

OBJECTIVES

Therapeutic hypothermia is widely employed for neuroprotection after cardiac arrest. However, concern regarding elevated drug concentrations during hypothermia and increased adverse drug reaction risk complicates concurrent pharmacotherapy. Many commonly used medications in critically ill patients rely on the cytochrome P450 3A isoform for their elimination. Therefore, our study objectives were to determine the effect of mild hypothermia on the in vivo pharmacokinetics of fentanyl and midazolam, two clinically relevant cytochrome P450 3A substrates, after cardiac arrest and to investigate the mechanisms of these alterations.

DESIGN

Prospective, randomized, controlled study.

SETTING

University research laboratory.

SUBJECTS

Thirty-two adult male Sprague-Dawley rats.

INTERVENTIONS

An asphyxial cardiac arrest rat model was used and mild hypothermia (33°C) was induced 1 hr post injury by surface cooling and continued for 10 hrs to mimic the prolonged clinical application of hypothermia accompanied by intensive care interventions. Fentanyl and midazolam were independently administered by intravenous infusion and plasma and brain concentrations were analyzed using ultraperformance liquid chromatography tandem mass spectrometry. Cytochrome P450 3a2 protein expression was measured and a Michaelis-Menten enzyme kinetic analysis was performed at 37°C and 33°C using control rat microsomes.

MEASUREMENTS AND MAIN RESULTS

Mild hypothermia decreased the systemic clearance of both fentanyl (61.5 ± 11.5 to 48.9 ± 8.95 mL/min/kg; p < .05) and midazolam (89.2 ± 12.5 to 73.6 ± 12.1 mL/min/kg; p < .05) after cardiac arrest. The elevated systemic concentrations did not lead to parallel increased brain exposures of either drug. Mechanistically, no differences in cytochrome P450 3a2 expression was observed, but the in vitro metabolism of both drugs was decreased at 33°C vs. 37°C through reductions in enzyme metabolic capacity rather than substrate affinity.

CONCLUSIONS

Mild hypothermia reduces the systemic clearances of fentanyl and midazolam in rats after cardiac arrest through alterations in cytochrome P450 3a2 metabolic capacity rather than enzyme affinity as observed with other cytochrome P450s. Contrasting effects on blood and brain levels further complicates drug dosing. Consideration of the impact of hypothermia on medications whose clearance is dependent on P450 3A metabolism is warranted.

Refractory delirium tremens: a case report and brief review

Delirium tremens is a common presentation in tertiary care hospitals. Severe and/or refractory delirium tremens is not as common, is potentially lethal, and requires intensive management. Usually delirium tremens responds to management with standard doses of benzodiazepines. Limited literature is available, however, for the management of refractory delirium tremens. We describe a case of refractory delirium tremens in which the patient was successfully managed with a combination of high doses of lorazapam, midazolam, and phenytoin.

Comparison of oral Midazolam-Ketamine and Midazolam-Promethazine as sedative agents in pediatric dentistry

BACKGROUND

Investigation was designed to evaluate the behavioral changes in children receiving dental treatment while they have been administered combination of Midazolam/Ketamine or Midazolam/Promethazine.

MATERIALS AND METHODS

This was a randomized double blind clinical trial with cases being selected from those uncooperative children aged 2 to 6 years from those referred for treatment under general anesthesia. Anxiety score of all cases were recorded before any attempt using Frankel's anxiety scoring system with those in negative category being included. Cases with at least a pair of similar size cavities on similar teeth were selected with each tooth being randomly allocated for one sedative regimen group. To avoid sequence effect, half of the patients received one regimen at the first visit while the other half received the other regimen as the first. Each case served as control for him or herself to reduce influencing factors. Child's reaction was recorded before, during, and at the end of dental procedure. SO2 as well as Pulse rate were recorded as the most critical vital signs. Collected data were then analyzed using analysis of variance (ANOVA) and paired t-test.

RESULTS

Patients' mean age was 3.5 years with 43% being male. Only 10% of the Ketamine/Midazolam group showed considerable amount of change in their behavior with a statistical significant difference being presented (P=0.029).

CONCLUSION

Under the current circumstances, Ketamine/Midazolam combination provided sufficient sedative effect in lower doses. However, Midazolam/Promethazine combination did not produce similar results.

Comparison of dexmedetomidine and three different doses of midazolam in preoperative sedation

Background:

This study was conducted to compare the efficacy and effects of dexmedetomidine and midazolam in preoperative sedation.

Materials and Methods:

A total of 125 patients in American Society of Anaesthesiologists (ASA) I-II were divided into three groups: Group I (n = 40) for controls, Group II (n = 40) for Dexmedetomidine (1 μg/kg), and group III was the midazolam group (n = 45). Group III was further divided into three subgroups according to the doses of midazolam: Group IIIA (n = 15) received 0.02 mg/kg, group IIIB (n = 15) received 0.04 mg/kg, and group IIIC (n = 15) received 0.06 mg/kg of midazolam. Drugs were infused over a 10-minute period with appropriate monitoring. Ramsay and visual analog scores, for sedation and anxiety, respectively, and mean arterial pressure, heart rate, and SpO₂ measurement, including respiratory rates were recorded, every 5 minutes for 30 minutes following infusion.

Results:

There was marked sedation and a decrease in anxiety in groups II and IIIC (P < 0.01). Mean arterial pressure (MAP) and heart rate (HR) decreased significantly in group II (P < 0.01 and P < 0.05, respectively), but there was no associated hypotension (MAP <60 mm Hg) or bradycardia (HR <50 bpm) (P < 0.05). Respiratory rates and SpO₂ values decreased in groups II, IIIA, IIIB, and IIIC. The differences in respiratory rates were not significant (P > 0.05); however, decrease in SpO₂ was significant in group IIIC (P < 0.01).

Conclusions:

Dexmedetomidine was as effective as higher doses of midazolam in sedation. The hemodynamic and respiratory effects were minimal. Although dexmedetomidine caused significant decrease in the blood pressure and heart rate, it probably just normalized increased levels caused by preoperative stress.

The discriminative stimulus effects of midazolam are resistant to modulation by morphine, amphetamine, dizocilpine, and γ-butyrolactone in rhesus monkeys

RATIONALE

Although abuse of benzodiazepines alone is uncommon, it is high in polydrug abusers, including those who primarily use opioids or stimulants.

OBJECTIVES

This study investigated whether drugs that are abused (e.g., amphetamine) or drugs that have mechanisms of action similar to abused drugs (e.g., morphine) alter the discriminative stimulus effects of the benzodiazepine midazolam.

METHODS

Three rhesus monkeys discriminated 0.56 mg/kg of midazolam while responding under a fixed-ratio 10 schedule of food presentation. Dose-effect curves were determined for midazolam alone and in the presence of morphine (opioid receptor agonist), amphetamine (dopamine receptor indirect agonist), dizocilpine (N-methyl-D: -aspartic acid receptor antagonist), or γ-butyrolactone (prodrug of γ-hydroxybutyrate, which acts primarily at GABA(B) receptors).

RESULTS

Doses of midazolam larger than 0.32 mg/kg produced ≥80% midazolam-lever responding. When administered alone, morphine, amphetamine, dizocilpine, and γ-butyrolactone did not produce midazolam-lever responding, although large doses of each drug eliminated responding; when administered in combination with midazolam, they did not alter the discriminative stimulus effects of midazolam up to doses that markedly decreased response rates.

CONCLUSIONS

The current study demonstrates a lack of modulation of the discriminative stimulus effects of midazolam by morphine, amphetamine, dizocilpine, and γ-butyrolactone. Other effects of benzodiazepines, such as their reinforcing effects, might be altered by these other drugs, or benzodiazepines might modulate the discriminative stimulus or reinforcing effects of the other drugs, which might contribute to the relatively high incidence of benzodiazepine abuse among polydrug abusers.