[Sedation induced by midazolam in intensive care: pharmacologic and pharmacokinetic aspects]

The impact of midazolam used in cataract surgery sedation on frontal QRS-T angle

WHAT IS KNOWN AND OBJECTIVE

Midazolam is one of the most commonly used drugs in procedures requiring sedoanalgesia. It affects the myocardium's ventricular depolarization and repolarization. Previous studies examining the arrhythmogenic effects of midazolam yielded conclusive results. These studies are based on QT and Tp -e distances. The frontal QRS-T angle (f-[QRS-T]a) is a new electro cardiac parameter that shows the heterogeneity of ventricular electrical activity. This study aims to examine the effect of midazolam on f-(QRS- T)a and other depolarization-repolarization parameters in patients who have had cataract surgery.

METHODS

The study included 177 patients administered midazolam as a sedoanalgesia during cataract surgery. The sedative effect was evaluated 2-3 minutes after a 0.05 mg/kg dose of midazolam was given. Sedation was assessed again by giving 0.5 mg every 2-3 minutes until the desired level of sedation was achieved. 12-lead electrocardiogram (ECG) recordings of all patients were taken just before and immediately after surgery. ECGs were used to calculate the QT interval, QTc interval, Tp -e interval, Tp -e/QT, Tp -e/ QTc ratios and f-(QRS-T)a.

RESULTS AND DISCUSSION

After cataract surgery, f-(QRS-T)a was unchanged compared to presurgery (29.14 ± 4.52 vs. 29.18 ± 5.39, p = 0.852). In addition, no significant change in QT(351.32 ± 21.98 vs. 351.94 ± 22.44, p = 0.091), QTc (384.05 ± 24.52 vs. 385.19 ± 26.12, p = 0.819), Tp -e interval (93.12 ± 9.60 vs. 94.44 ± 8.82, p = 0.179) and Tp -e/QT (0.27 ± 0.02 vs. 0.28 ± 0.03, p = 0.664), Tp -e/ QTc ratios (0.28 ± 0.02 vs. 0.29 ± 0.03, p = 0.655) was observed after surgery when compared to presurgery values. Significant ventricular and supraventricular arrhythmias were not observed in any patient during the operation.

WHAT IS NEW AND CONCLUSION

Midazolam did not affect f -(QRS-T) with classical repolarization parameters in patients who underwent cataract surgery, according to this study. Midazolam has been found to be safe for the heart in sedoanalgesia. These results show that sedation with midazolam can be performed without electrocardiogram monitoring.

Midazolam sedation in palliative medicine: retrospective study in a French center for cancer control

BACKGROUND

French legislation about sedation in palliative medicine evolved in 2016 with the introduction of a right to deep and continuous sedation, maintained until death. The objective was to describe midazolam sedation at the COL (Centre Oscar Lambret [Oscar Lambret Center], French regional center for cancer control), in order to establish a current overview before the final legislative changes.

METHODS

Descriptive, retrospective and single-center study, concerning major patients in palliative care hospitalized from 01/01/2014 to 12/31/2015, who had been sedated by midazolam. The proven sedations (explicitly named) and the probable sedations were distinguished.

RESULTS

A total of 54 sedations were identified (48 proven, 6 probable). Refractory symptoms accounted for 48.1% of indications, complications with immediate risk of death 46.3%, existential suffering 5.6%. Titration was performed in 44.4% of cases. Sedation was continuous until death for 98.1% of the cases. Probable sedation had a higher failure rate than proven sedation. Significant differences existed for the palliative care unit compared to other units regarding information to the patient, their consent, anticipation, mention by correspondence and carrying out titrations. When patients had already been treated with midazolam, the induction doses, initial maintenance doses, and doses at the time of death were significantly higher. For those receiving opioids, the maintenance dose at the time of death was higher. No comparison found a difference in overall survival.

CONCLUSIONS

After a sufficient follow-up has enabled teams to familiarize with this new legislation, reflection on sedation should be conducted to adapt to final recommendations.

[Agents for sedation and analgesia in the intensive care unit]

Sedation-analgesia for critically ill patients is usually performed with the combination of a sedative agent and an opioid. Midazolam and propofol are the agents most commonly used for sedation in ICU. The quality of the sedation is quite comparable with both agents, but pharmacokinetic properties of propofol allow a more rapid weaning process from mechanical ventilation. However, implementation of algorithms to adjust drug dosages reduces ventilator days and limits the kinetic differences between propofol and midazolam. Among the adverse events associated with propofol, propofol infusion syndrome is a rare but lethal aspect of propofol therapy. Opioids are the mainstay of analgesic therapy. They interact synergistically with hypnotics. Sufentanil, fentanyl and morphine are the most frequently used opioids. Remifentanil is an ultrashort acting opiate that does not appear to accumulate with prolonged use. The advent of remifentanil has allowed the use of analgesia-based sedation.

Midazolam (dormicum®): Clinical practice guidelines

Introduction. Three benzodiazepines are available for IV injection and are commonly used in anesthesia practice: diazepam, lorazepam, and midazolam. The last is the most frequently used in anaesthesia practice. Benzodiazepines induce amnesia and sedation secondary to potentiation of the inhibitory neurotransmitter gamma amino-butyric acid (GABA). Although sleep inducing doses of midazolam (0,2-0,4 mg/kg) may produce unconsciousness in one to three minutes it is commonly used for sedation and to ensure amnesia and premedication. The effects of midazolam on the cardiovascular system are minimal. Mild decreases in blood pressure and heart rate are indicative of its sedative effect. There have been reports of respiratory depression with diazepam, however this response is dose dependent and can be marked if concomitant doses of narcotics are used. Because of its potential for depressing respiration, especially if given with narcotics, the respiratory response of these patients needs to be monitored. Intravenous midazolam should be titrated to effect and the benzodiazepine antagonist flumazenil should be immediately available. .