Evaluation of the brain anaesthesia response monitor during anaesthesia for cardiac surgery: a double-blind, randomised controlled trial using two doses of fentanyl.

The brain anaesthesia response (BAR) monitor uses a method of EEG analysis, based on a model of brain electrical activity, to monitor the cerebral response to anaesthetic and sedative agents via two indices, composite cortical state (CCS) and cortical input (CI). It was hypothesised that CCS would respond to the hypnotic component of anaesthesia and CI would differentiate between two groups of patients receiving different doses of fentanyl. Twenty-five patients scheduled to undergo elective first-time coronary artery bypass graft surgery were randomised to receive a total fentanyl dose of either 12 µg/kg (fentanyl low dose, FLD) or 24 µg/kg (fentanyl moderate dose, FMD), both administered in two divided doses. Propofol was used for anaesthesia induction and pancuronium for intraoperative paralysis. Hemodynamic management was protocolised using vasoactive drugs. BIS, CCS and CI were simultaneously recorded. Response of the indices (CI, CCS and BIS) to propofol and their differences between the two groups at specific points from anaesthesia induction through to aortic cannulation were investigated. Following propofol induction, CCS and BIS but not CI showed a significant reduction. Following the first dose of fentanyl, CI, CCS and BIS decreased in both groups. Following the second dose of fentanyl, there was a significant reduction in CI in the FLD group but not the FMD group, with no significant change found for BIS or CCS in either group. The BAR monitor demonstrates the potential to monitor the level of hypnosis following anaesthesia induction with propofol via the CCS index and to facilitate the titration of fentanyl as a component of balanced anaesthesia via the CI index.

Novel Preoxygenation Technique to Deliver High-Flow Oxygen in a Patient With Facial Trauma: A Case Report.

This case demonstrates a novel preoxygenation technique in a patient with difficult access to the airway after a traumatic facial injury. To find a solution, a fusion of oxygenation equipment was trialed by altering and combining a tracheostomy mask and the tubing of an Optiflow circuit from which the nasal cannula component had been removed. This novel combination delivered high-flow humidified oxygen (60 L/min) orally, avoided further facial injury, and was well tolerated by the patient. Effective preoxygenation was confirmed by arterial gas measurements. This study supports the use of this novel Optiflow-tracheostomy mask fusion device in appropriately selected cases.

A comparison of dexmedetomidine versus conventional therapy for sedation and hemodynamic control during carotid endarterectomy performed under regional anesthesia.

The properties of dexmedetomidine (DEX) that result in titratable sedation and sympathetic modulation suggest that it would be suitable for use during carotid endarterectomy (CEA) performed under regional anesthesia. We performed a randomized, double-blind study in 56 patients having CEA under regional anesthesia and compared hemodynamic control using DEX versus a conventional sedation technique using midazolam and fentanyl standard (STD). Sedation was titrated to a Ramsay Sedation Score of 2-4 in both groups. The primary outcome was the number of pharmacological interventions required to treat deviations of arterial blood pressure and heart rate outside of predetermined limits. We also compared recovery hemodynamic profiles, patient satisfaction, and adverse cardiac and neurological events. There was no difference in the overall rate of hemodynamic interventions (DEX 80% versus STD 79%; P = 1.0). However, the nature of interventions differed in that patients in the DEX group were less likely to require treatment for hypertension and/or tachycardia (DEX 40% versus STD 72%; P = 0.03). The number of interventions per patient for hypertension and/or tachycardia was also lesser in the DEX group (P = 0.02). There were no significant differences in the numbers of patients needing intraoperative treatment for hypotension or bradycardia or in the need for intraarterial shunting. In the postanesthesia care unit, more patients in the DEX group required hemodynamic drug interventions (DEX 11, 44%, versus STD 4, 14%; P = 0.03). These were primarily for hypotension (DEX 7, 28% versus STD 3, 11%; P = 0.16). The number of patients requiring no additional pain relief in the postanesthesia care unit was significantly larger for patients in the DEX group (DEX 18, 72% versus STD 11, 38%; P = 0.027). DEX provides an acceptable alternative, without superiority to standard techniques for sedation during awake CEA.