Impact of Target-Controlled Infusion (TCI) of Propofol on State- and Response-Entropy and Sedation Depth During Flexible Bronchoscopy

Abstract

Background: The increasing use of flexible bronchoscopy for diagnostic and interventional purposes requires further knowledge on feasible sedation regimens. We investigated the potential benefit of Target- Controlled Infusion (TCI) of propofol on sedation depth. Methods: Fifty-four patients scheduled for elective flexible bronchoscopy were allocated to receive propofol sedation using either intermittent boluses or Target Controlled Infusion (TCI). Endpoints included Entropy monitoring to evaluate sedation depth, sedation quality and the total amount of propofol. Results: There were no significant differences between both cohorts regarding the number of adverse sedation-related events. The mean applied dose of propofol was significantly higher in the Target-Controlled Infusion group (405±249 mg vs. 324±94 mg, p=0.015). Until patients reached loss of consciousness (LOC), State Entropy (SE) and Response Entropy (RE) levels were comparable among both sedation regimens. During the procedure, both parameters decreased to significantly lower levels in the TCI-cohort (SE: 77.7±13.2 vs. 88.8±8.6 (p=0.002) and RE: 69±12.6 vs. 79±8.7 (p=0.005)). Examination conditions, as rated by proceduralists and assisting nurses, were superior in the TCI-cohort. In addition, restraining measurements, due to uncontrolled movement during the examination needed to be applied more often to patients in the bolus cohort (body restraint: 26 (96%) vs. 18 (67%), p=0.005). Conclusion: Target-Controlled Infusion of propofol complies with the requirements of flexible bronchoscopy by providing a deep and steady level of sedation without impairing patient’s safety. In addition, there is evidence that overall sedation quality is superior, both for bronchoscopist and assisting staff.