Psychomotor and Clinical Assessment of Flumazenil as an Antagonist of Midazolam

Simulation-Based Gastrointestinal Endoscopy Sedations: A Novel Validation to Multidrug Pharmacodynamic Modeling

Pharmacodynamic models have described the interactions between anesthetics. Applying the models to clinical practice is still problematic due to inherent limitations: 1. modeling conditions are different from practice. 2. One model can only describe one endpoint. To tackle these, we propose a new method of model validation for recovery and intraprocedural sedation adequacy with a three-drug pharmacodynamic model using six published clinical studies that contain midazolam, opioid, and propofol. Mean drug dose, intraprocedural sedation level, procedure, and recovery time are extracted from each study. Simulated drug regimens are designed to best approximate study conditions. A published deep sedation model is used for simulation. Model-predicted recovery time and intraprocedural sedation scores are compared with the original clinical study outcomes. The model successfully predicted recovery times in eight out of nine regimens. Lower doses of midazolam are associated with faster recovery. Model prediction of intraprocedural sedation level was compatible with the clinical studies in five out of seven regimens. The three-drug pharmacodynamic model describes the course of gastrointestinal endoscopy sedations from clinical studies well. Model predictions are consistent with the results from clinical studies. The approach implies that large scale validation can be performed repeatedly.

Doxapram as an additive to propofol sedation for endoscopic retrograde cholangiopancreatography: a placebo-controlled, randomized, double-blinded study

Background

Endoscopic retrograde cholangiopancreatography (ERCP) requires moderate to deep sedation, usually with propofol. Adverse effects of propofol sedation are relatively common, such as respiratory and cardiovascular depression. This study was conducted to determine if doxapram, a respiratory stimulant, could be used to reduce the incidence of respiratory depression.

Methods

This is a single-center, prospective randomized double-blind study performed in the endoscopy unit of Helsinki University Central Hospital. 56 patients were randomized in a 1:1 ratio to either receive doxapram as an initial 1 mg/kg bolus and an infusion of 1 mg/kg/h (group DOX) or placebo (group P) during propofol sedation for ERCP. Main outcome measures were apneic episodes and hypoxemia (SpO₂ < 90%). Mann–Whitney test for continuous variables and Fisher’s exact test for discrete variables were used and mixed effects modeling to take into account repeated measurements on the same subject and comparing both changes within a group as a function of time and between the groups.

Results

There were no statistically significant differences in apneic episodes (p = 0.18) or hypoxemia (p = 0.53) between the groups. There was a statistically significant rise in etCO₂ levels in both groups, but the rise was smaller in group P. There was a statistically significant rise in Bispectral Index (p = 0.002) but not modified Observer’s Assessment of Agitation/Sedation (p = 0.21) in group P. There were no statistically significant differences in any other measured parameters.

Conclusions

Doxapram was not effective in reducing respiratory depression caused by deep propofol sedation during ERCP. Further studies are warranted using different sedation protocols and dosing regimens.

Clinical trial registration ClinicalTrials.gov ID NCT02171910.

Target-controlled infusion of propofol versus intermittent bolus of a sedative cocktail regimen in deep sedation for gastrointestinal endoscopy: comparison of cardiovascular and respiratory parameters

OBJECTIVE

To investigate whether target-controlled infusion (TCI) with propofol, a method that has theoretically better control of drug concentration, produces less cardiovascular and respiratory suppression than an intermittent bolus of a sedative cocktail regimen in deep sedation for gastrointestinal endoscopy.

METHODS

In total 100 participants who had undergone esophagoduodenoscopy (EGD) and 120 who had undergone colonoscopy were prospectively and randomly enrolled to receive TCI with propofol or intermittent bolus of cocktail regimen containing midazolam, alfentanil and propofol until they were unresponsive to verbal commands. The target concentration was adjusted and the bolus of the cocktail regimen was added based on their responses. The nadir values of heart rate, blood pressure and oxygen saturation during and after the procedure were recorded.

RESULTS

The nadir systolic blood pressure during the endoscopy in the cocktail regimen group was significantly lower than that in the TCI with propofol group. In the cocktail regimen group, the incidence of hypotension during colonoscopy and that of bradycardia during EGD were higher than those in the TCI with propofol group. No participants in the TCI with propofol group experienced hypoxia during endoscopy. In the cocktail regimen group, six participants who had undergone EGD and six who had undergone colonoscopy showed transient hypoxic episodes during or after endoscopy.

CONCLUSION

TCI with propofol produced less cardiovascular and respiratory suppression than intermittent bolus of a sedative cocktail regimen in deep sedation for gastrointestinal endoscopy.

The effects of midazolam on pure tone audiometry, speech audiometry, and audiological reaction times in human volunteers

Auditory evoked potentials are effected by benzodiazepines, as is cortical processing of auditory stimuli. The effect of benzodiazepines on auditory sensitivity has not, however, been studied. We designed the present study to investigate the effect of sedative doses of midazolam on pure tone and speech audiometry and on audiological reaction times in healthy volunteers. Thirty volunteers underwent baseline audiological assessment for pure tones and speech and had their audiological reaction times measured at 10 and 50 dB above their threshold hearing level at a frequency of 1 kHz. Subjects were then randomly assigned to one of two groups. Group A (n = 15) received midazolam (0.04 mg/kg) IV, and Group B (n = 15) received a similar volume of placebo IV. The audiological tests were repeated 5 min later, and performance was compared with baseline data. Scheffé post hoc tests were used to assess the significance of changes in each group. There was no pre- to posttest change in audiological performance in either the placebo group (P = 0.194) or the midazolam group (P = 0.957). Speech audiometry performance was likewise unaffected by midazolam (P = 0.154). Reaction time at the 10-dB and 50-dB sensation levels were both significantly prolonged after midazolam administration (P = 0.023 and P = 0.012, respectively). In this study, we demonstrate that sedation with midazolam (0.04 mg/kg) does not alter pure tone or speech audiometric thresholds, but it does significantly delay the reaction time to auditory stimuli. Medical practitioners should advise midazolam-sedated patients of their impaired reaction to auditory warning signals (e.g., traffic and car horns) as part of the day-ward discharge recommendations.

IMPLICATIONS

In this study, we demonstrate that sedation of healthy volunteers with the benzodiazepine midazolam, in the common clinical dosage, does not affect their hearing capability as measured by pure tone and speech audiometry. However, one's ability to react to auditory signals is impaired after midazolam, which may have implications for patients after day-case procedures.