A randomised crossover trial of post-operative cognitive and psychomotor recovery from benzodiazepine sedation: effects of reversal with flumazenil over a prolonged recovery period

Retrospective audit of midazolam dose and intravenous sedation record keeping in a primary care oral surgery service

Regular and robust audit of conscious sedation practice is key to the delivery of safe and effective patient care in all clinical settings. Analysis of outcomes will help to highlight any necessary modifications to procedures and techniques. The Intercollegiate Advisory Committee for Sedation in Dentistry (IACSD) states that conscious sedation procedures must be the subject of robust and regular audit in which every member within the team takes part.¹ This completed audit cycle highlighted the efficacy of intravenous (IV) midazolam in anxious patients undergoing oral surgical procedures and the suitability for its use in the primary care setting. No patient safety concerns or complications were recorded in this audit and midazolam was administered within the recommended dose range. By the conclusion of two audit cycles, all clinicians providing intravenous sedation within the service were aware of the missing elements in sedation record-keeping and were able to complete accurate contemporaneous records before, during and after conscious sedation, ensuring the continuous delivery of high-quality, safe, and patient-centred care.

Academy of Medicine, Singapore clinical guideline on the use of sedation by non-anaesthesiologists during gastrointestinal endoscopy in the hospital setting

INTRODUCTION

In Singapore, non-anaesthesiologists generally administer sedation during gastrointestinal endoscopy. The drugs used for sedation in hospital endoscopy centres now include propofol in addition to benzodiazepines and opiates. The requirements for peri-procedural monitoring and discharge protocols have also evolved. There is a need to develop an evidence-based clinical guideline on the safe and effective use of sedation by non-anaesthesiologists during gastrointestinal endoscopy in the hospital setting.

METHODS

The Academy of Medicine, Singapore appointed an expert workgroup comprising 18 gastroenterologists, general surgeons and anaesthesiologists to develop guidelines on the use of sedation during gastrointestinal endoscopy. The workgroup formulated clinical questions related to different aspects of endoscopic sedation, conducted a relevant literature search, adopted Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology and developed recommendations by consensus using a modified Delphi process.

RESULTS

The workgroup made 16 recommendations encompassing 7 areas: (1) purpose of sedation, benefits and disadvantages of sedation during gastrointestinal endoscopy; (2) pre-procedural assessment, preparation and consent taking for sedation; (3) Efficacy and safety of drugs used in sedation; (4) the role of anaesthesiologist administered sedation during gastrointestinal endoscopy; (5) performance of sedation; (6) post-sedation care and discharge after sedation; and (7) training in sedation for gastrointestinal endoscopy for non-anaesthesiologists.

CONCLUSION

These recommendations serve to guide clinical practice during sedation for gastrointestinal endoscopy by non-anaesthesiologists in the hospital setting.

Effect of Midazolam in Addition to Propofol and Opiate Sedation on the Quality of Recovery After Colonoscopy: A Randomized Clinical Trial

BACKGROUND

There is a concern that midazolam, when used as a component of sedation for colonoscopy, may impair cognition and prolong recovery. We aimed to identify whether midazolam produced short- and longer-term effects on multiple dimensions of recovery including cognition.

METHODS

A 2-center double-blinded, placebo-controlled, parallel-group, randomized, phase IV study with a 1:1 allocation ratio was conducted in adults ≥18 years of age undergoing elective outpatient colonoscopy, with sufficient English language proficiency to complete the Postoperative Quality of Recovery Scale (PostopQRS). Participants were administered either midazolam (0.04 mg·kg) or an equivalent volume of 0.9% saline before sedation with propofol with or without an opiate. The primary outcome was incidence of recovery in the cognitive domain of the PostopQRS on day 3 after colonoscopy, which was analyzed using a χ test. Secondary outcomes included recovery in other domains of the PostopQRS over time, time to eye-opening, and hospital stay, and patient and endoscopist satisfaction. All hypotheses were defined before recruitment.

RESULTS

During September 2015 to June 2018, 406 patients were allocated to either midazolam (n = 201) or placebo (n = 205), with one withdrawn before allocation. There was no significant difference in recovery in the cognitive domain of the PostopQRS on day 3 after colonoscopy (midazolam 86.8% vs placebo 88.7%, odds ratio, 0.838; 95% confidence interval [CI], 0.42-1.683; P= .625). Furthermore, there was no difference in recovery over time in the cognitive domain of the PostopQRS (P = .534). Overall recovery of the PostopQRS increased over time but was not different between groups. Furthermore, there were no differences between groups for nociceptive, emotive, activities-of-daily-living domains of the PostopQRS. Patient and endoscopist satisfaction were high and not different. There were no differences in time to eye-opening (midazolam 9.4 ± 12.8 minutes vs placebo 7.3 ± 0.7 minutes; P = .055), or time to hospital discharge (midazolam 103.4 ± 1.4 minutes vs placebo 98.4 ± 37.0 minutes; P = .516).

CONCLUSIONS

The addition of midazolam 0.04 mg·kg as adjunct to propofol and opiate sedation for elective colonoscopy did not show evidence of any significant differences in recovery in the cognitive domain of the PostopQRS, overall quality of recovery as measured by the PostopQRS, or emergence and hospital discharge times. The use of midazolam should be determined by the anesthesiologist.

Clinical analysis of moderate-to-deep-sedation by nonmedical sedation practitioners in 597 patients undergoing gastrointestinal endoscopy: a retrospective study

BACKGROUND AND STUDY AIM

The purpose of this study was to evaluate whether moderate-to-deep sedation with propofol and alfentanil can be administered safely by nonmedical sedation practitioners, and the outcomes of this practice in the Netherlands. We retrospectively analyzed the occurrence of sedation-related complications in patients undergoing gastrointestinal endoscopic procedures.

PATIENTS AND METHODS

In this study, 597 adult patients consecutively underwent upper gastrointestinal endoscopic procedures. The health status of the patients was screened according to a standardized protocol, and the patients were sedated by trained nonmedical sedation practitioners. Their vital signs were continuously monitored and recorded. All patients received oxygen, and the depth of sedation was continuously assessed and recorded. Mild and severe complications were recorded and analyzed.

RESULTS

All patients recovered uneventfully, and no mortality occurred. Overall, of the 597 sedated patients, 85 had mild and 4 had severe complications. Hypoxemia and upper airway obstruction, which were easily managed by trained nonmedical sedation practitioners, were the most common events. Hypotension was rare. No signs or symptoms suggestive of aspiration were reported.

CONCLUSION

Moderate-to-deep sedation has been and continues to be a risky medical procedure. Serious complications of propofol/opioid-based sedation, especially respiratory and cardiovascular adverse events, may occur. These complications need to be recognized rapidly and appropriately managed. Our study shows that well-trained nonmedical sedation practitioners can be entrusted to take responsibility for the safe administration of moderate-to-deep sedation.

Pharmacokinetics of high-dose intravenous melatonin in humans

This crossover study investigated the pharmacokinetics and adverse effects of high-dose intravenous melatonin. Volunteers participated in 3 identical study sessions, receiving an intravenous bolus of 10 mg melatonin, 100 mg melatonin, and placebo. Blood samples were collected at baseline and 0, 60, 120, 180, 240, 300, 360, and 420 minutes after the bolus. Quantitative determination of plasma melatonin concentrations was performed using a radioimmunoassay technique. Pharmacokinetic parameters were estimated by a compartmental pharmacokinetic analysis. Adverse effects included assessments of sedation and registration of other symptoms. Sedation, evaluated as simple reaction times, was measured at baseline and 120, 180, 300, and 420 minutes after the bolus. Twelve male volunteers completed the study. Median (IQR) Cmax after the bolus injections of 10 mg and 100 mg of melatonin were 221,500.0 (185,637.5-326,175.0) pg/mL and 1,251,500.0 (864,375.0-1,770,500.0) pg/mL, respectively; mean (SD) t1/2 was 42.3 (5.6) minutes and 46.2 (6.2) minutes; mean (SD) Vd was 1.6 (0.9) L/kg and 2.0 (0.8) L/kg; mean (SD) CL was 0.0253 (0.0096) L/min · kg and 0.0300 (0.0120) L/min · kg; and median (IQR) AUC0- ∞ , 8,997,633.0 (6,071,696.2-11,602,811.9) pg · min/mL and 54,685,979.4 (36,028,638.6-105,779,612.0) pg · min/mL. High-dose intravenous melatonin did not induce sedation, evaluated as simple reaction times. No adverse effects were reported in the study.

Does Intravenous Midazolam Dose Influence the Duration of Recovery Room Stay Following Outpatient Third Molar Surgery?

PURPOSE

To evaluate the impact of intravenous midazolam dose on the duration of recovery room stay for patients undergoing outpatient third molar surgery.

MATERIALS AND METHODS

Using a retrospective cohort study design, a sample of patients undergoing outpatient third molar surgery under intravenous sedation at Mayo Clinic from 2010 to 2014 was identified. All patients underwent extraction of all 4 third molars during a single operative procedure and the age range was limited to 14 to 29 years. The primary predictor variable was the total dose of intravenous midazolam administered during sedation. The primary outcome variable was recovery room length of stay (LOS) after completion of surgery. Multiple covariates also abstracted included patient age, gender, American Society of Anesthesiologists (ASA) score, duration of surgical procedure, complexity of surgical procedure, types and dosages of all intravenous medications administered during sedation, and volume of crystalloid fluid administered perioperatively. Univariable and multivariable models were developed to evaluate associations between the primary predictor variable and covariates relative to the primary outcome variable.

RESULTS

The study sample was composed of 2,610 patients. Mean age was 18.3 years (SD, 3.0 yr; range, 14 to 29 yr) and gender distribution was 52% female. Mean dosage of midazolam administered was 4.1 mg (SD, 1.1 mg; range, 0.5 to 10.0 mg). Variables predicting shorter LOS at multivariable analysis included older age (P < .001), male gender (P = .004), and administration of larger crystalloid fluid volumes (P < .001). Variables predicting longer LOS included higher ASA score (P < .001), administration of ketamine (P < .001), and administration of ketorolac (P < .001). The dose of midazolam administered during sedation was not found to be significantly associated with prolonged recovery room LOS in univariable or multivariable settings.

CONCLUSION

Dosage of intravenous midazolam does not appear to significantly impact the duration of recovery room stay in the prototypical patients undergoing sedation for outpatient third molar surgery.

Significant and safe shortening of the recovery time after flumazenil-reversed midazolam sedation

BACKGROUND

Endoscopy under midazolam sedation requires a 2-h recovery facility.

AIM

To study the potential of shortening patients' stay without jeopardizing patients' safety by the use of the benzodiazepine-antagonist flumazenil in the everyday practice and to investigate the feasibility of a study comparing midazolam with recovery with midazolam-flumazenil and immediate discharge.

METHODS

Consecutive ambulatory patients referred for endoscopy under midazolam sedation with ASA I or II, escorted by a person, were eligible. Flumazenil was given on arrival in the recovery room. Patients were discharged when adequate Aldrete scores and physical mobility were present. The next day, they were contacted by telephone.

RESULTS

A total of 1,506 patients participated. They received 5 mg midazolam, while 887 patients also received 50 mcg fentanyl. The median dose of flumazenil was 0.2 mg. Oxygen desaturation (sO2 <92%) occurred in 15% during the procedure without an effect on recovery and discharge times. Patients left the department 65 min after the last midazolam administration. The majority (82.7%) were fully alert during their journey home. At home, 2.7% went to bed, 45.2% took a nap, and 40% undertook activities. Almost every patient (98.8%) liked the shortened recovery time. Three patients had an incident (fainting, fall, and near-fall) without consequences. Based on this low incidence, a non-inferiority comparison of midazolam-flumazenil with midazolam-recovery would require a total of 32,650 patients.

CONCLUSIONS

Administration of flumazenil resulted in a safe shortening of the recovery period and offers the possibility for substantial savings in time, space, and nurse resources. A non-inferiority comparison will not be practicable.

Modulation of vigilance in the primary hypersomnias by endogenous enhancement of GABAA receptors

The biology underlying excessive daytime sleepiness (hypersomnolence) is incompletely understood. After excluding known causes of sleepiness in 32 hypersomnolent patients, we showed that, in the presence of 10 μM γ-aminobutyric acid (GABA), cerebrospinal fluid (CSF) from these subjects stimulated GABA(A) receptor function in vitro by 84.0 ± 40.7% (SD) relative to the 35.8 ± 7.5% (SD) stimulation obtained with CSF from control subjects (Student's t test, t = 6.47, P < 0.0001); CSF alone had no effect on GABA(A) signaling. The bioactive CSF component had a mass of 500 to 3000 daltons and was neutralized by trypsin. Enhancement was greater for α2 subunit- versus α1 subunit-containing GABA(A) receptors and negligible for α4 subunit-containing ones. CSF samples from hypersomnolent patients also modestly enhanced benzodiazepine (BZD)-insensitive GABA(A) receptors and did not competitively displace BZDs from human brain tissue. Flumazenil--a drug that is generally believed to antagonize the sedative-hypnotic actions of BZDs only at the classical BZD-binding domain in GABA(A) receptors and to lack intrinsic activity--nevertheless reversed enhancement of GABA(A) signaling by hypersomnolent CSF in vitro. Furthermore, flumazenil normalized vigilance in seven hypersomnolent patients. We conclude that a naturally occurring substance in CSF augments inhibitory GABA signaling, thus revealing a new pathophysiology associated with excessive daytime sleepiness.

A quantitative system pharmacology computer model for cognitive deficits in schizophrenia

Although the positive symptoms of schizophrenia are reasonably well-controlled by current antipsychotics, cognitive impairment remains largely unaddressed. The Matrics initiative lays out a regulatory path forward and a number of targets have been tested in the clinic, so far without much success. To address this translational disconnect, we have developed a mechanism-based humanized computer model of a relevant key cortical brain network with schizophrenia pathology involved with the maintenance aspect of working memory (WM). The model is calibrated using published clinical experiments on N-back WM tests. We further simulate the opposite effect of γ-aminobutyric acid (GABA) modulators lorazepam and flumazenil and of a published augmentation trial of clozapine with risperidone, illustrating the introduction of new targets and the capacity of predicting the effects of polypharmacy. This humanized approach allows for early prospective and quantitative assessment of cognitive outcome in a central nervous system (CNS) research and development project, thereby hopefully increasing the success rate of clinical trials.CPT: Pharmacometrics & Systems Pharmacology (2013) 2, e36; doi:10.1038/psp.2013.12; advance online publication 3 April 2013.

Complications Associated with Intravenous Midazolam Sedation in Anxious Dental Patients

Aim

This prospective study was designed to establish the nature, frequency and sequelae of complications arising in patients receiving dental treatment under intravenous midazolam sedation.

Methods

All patients attending the Sedation Department at Newcastle Dental Hospital for intravenous sedation over a six-month period were audited. A standardised data-collection pro forma was designed in order to collect data relating to the patient, the sedation episode, the dental treatment and any complications arising. The published standard used in this study states that the incidence of complications should be no more than 8%.

Results

Four hundred and one patients were included. The mean dose of midazolam administered was 7.6 mg with a mean titration rate of 0.9 mg/min. Complications were reported in 12 patients (3%), 11 of which were minor and one moderate. All complications were managed successfully within the department with no lasting sequelae. Treatment was completed in 382 (95.7%) patients, with failure to complete treatment in 17 (4.3%) patients due to disinhibition (1), poor cooperation (10), and the sedation wearing off (6).

Conclusion

The standard was met because complications arising were infrequent (3%) and predominantly minor in nature. Complications were managed conservatively and effectively, with all patients being discharged home the same day with no lasting sequelae. The study demonstrates that intravenous midazolam provides a safe sedation technique, suitable for adult dental patients in primary care, when administered by trained personnel on carefully selected patients and in accordance with nationally agreed protocols and guidelines.

The effect of transmucosal 0.2 mg/kg midazolam premedication on dental anxiety, anaesthetic induction and psychological morbidity in children undergoing general anaesthesia for tooth extraction

BACKGROUND

The project aims were to evaluate the benefit of transmucosal midazolam 0.2 mg/kg pre-medication on anxiety, induction behaviour and psychological morbidity in children undergoing general anaesthesia (GA) extractions.

METHOD

One hundred and seventy-nine children aged 5-10 years (mean 6.53 years) participated in this randomised, double blind, placebo-controlled trial. Ninety children had midazolam placed in the buccal pouch. Dental anxiety was recorded preoperatively and 48 hours later using a child reported MCDAS-FIS scale. Behaviour at anaesthetic induction was recorded and psychological morbidity was scored by the parent using the Rutter Scale preoperatively and again one week later. Subsequent dental attendance was recorded at one, three and six months after GA.

RESULTS

While levels of dental anxiety did not reduce overall, the most anxious patients demonstrated a reduction in anxiety after receiving midazolam premedication (p = 0.01). Neither induction behaviour nor psychological morbidity improved. Irrespective of group, parents reported less hyperactive (p = 0.002) and more pro-social behaviour (p = 0.002) after the procedure; older children improved most (p = 0.048). Post-GA dental attendance was poor and unaffected by premedication.

CONCLUSION

0.2 mg/kg buccal midazolam provided some evidence for reducing anxiety in the most dentally anxious patients. However, induction behaviour, psychological morbidity and subsequent dental attendance were not found to alter.

Sedation for middle ear surgery: prospective clinical trial comparing propofol and midazolam

During middle-ear-surgery under local anaesthesia (MES-LA), patients report hearing noises, feeling anxious, and experiencing earache. In a prospective randomized clinical trial, we compared propofol and midazolam for sedation in 68 patients scheduled for MES-LA. The starting dose of propofol was 1 to 1.5 mg per kilogram intravenously, followed by 1 to 2 mg per kilogram per hour given by infusion. The starting dose of midazolam was 0.02 to 0.05 mg per kilogram intravenously, followed by 0.01 to 0.02 mg per kilogram intravenously. Metamizol and fentanyl were added when required. Sedation was titrated to a Ramsay score of 3 to 4 and a bispectral index value of 70 to 80. Patients were assessed for vital parameters and sedation and pain scores. In the recovery room, readiness for discharge and satisfaction of both patient and surgeon with the procedure were assessed. The group receiving propofol had a significantly lower heart rate, shorter duration of sedation, and earlier readiness for discharge (p<0.05). There were no significant differences in other parameters evaluated. Seventy-nine per cent of patients in the group receiving propofol and 91.1% receiving midazolam would choose the same method of anaesthesia and sedation for any further MES-LA. Our results suggest that, compared to midazolam, propofol is more suitable for sedation in patients undergoing MES-LA. However, appropriate patient selection, adequate preparation, and careful monitoring are mandatory.

Dial "T" for Testing: Technological Flexibility in Neuropsychological Assessment

Computer-automated neuropsychological testing can be conducted over the telephone via interactive voice response (IVR) technology by adapting cognitive measures traditionally administered by a clinician or in paper-and-pencil formats. By utilizing automated telephone interviews in neuropsychological research, time and money can be saved, and patients can be assessed remotely. This paper reviews the use of IVR to assess neuropsychological functioning in six studies that examined alcohol impairment of mental and physical functioning, cognitive and psychomotor recovery after surgery, and impairment resulting from central nervous system disease. Future directions for expanding application of cognitive performance assessment via IVR are discussed.

A randomised, controlled trial of cognitive and psychomotor recovery from midazolam sedation following reversal with oral flumazenil

Flumazenil is traditionally administered intravenously to reverse the adverse effects of over sedation with benzodiazepines. The aim of this study was to test postoperative cognitive and psychomotor recovery from midazolam conscious sedation, following reversal with orally administered flumazenil. It was hypothesised that when administered by the oral route, flumazenil may enhance recovery over a prolonged period, thus increasing safety. Eighteen patients requiring intravenous midazolam sedation for dental treatment completed a randomised, double-blind, crossover trial. Following treatment the patients' sedation was reversed using either flumazenil or saline (as placebo), administered orally, on alternate appointments. Assessment of mood and cognitive function were undertaken using ClinPhone.cdr(R), a highly sensitive and specific computerised battery of cognitive tests administered by telephone prior to sedation and every hour for seven hours post reversal. Results indicate that within 20 min of administration, oral flumazenil is capable of partially reversing some cognitive and psychomotor impairments but the attentional and stimulus discrimination effects of midazolam sedation still remain.