A randomized controlled trial demonstrates that a novel closed-loop propofol system performs better hypnosis control than manual administration

Abstract

A randomized controlled trial demonstrates that a novel closed-loop propofol system performs better hypnosis control than manual administration Une étude randomisée contrôlée démontre qu'un système innovant d'administration de propofol en circuit fermé permet un meilleur contrôle de l'hypnose qu'une administration manuelle Abstract Purpose The purpose of this randomized control trial was to determine the performance of a novel rule-based adaptive closed-loop system for propofol administration using the bispectral index (BISÒ) and to compare the system's performance with manual administration. The effectiveness of the closed-loop system to maintain BIS close to a target of 45 was determined and compared with manual administration. Methods After Institutional Review Board approval and written consent, 40 patients undergoing major surgery in a tertiary university hospital were allocated to two groups using computer-generated block randomization. In the Closed-loop group (n = 20), closed-loop control was used to maintain anesthesia at a target BIS of 45, and in the Control group (n = 20), propofol was administered manually to maintain the same BIS target. To evaluate each technique's performance in maintaining a steady level of hypnosis, the BIS values obtained during the surgical procedure were stratified into four clinical performance categories relative to the target BIS: B 10%, 11-20%, 21-30%, or [ 30% defined as excellent, good, poor, or inadequate control of hypnosis, respectively. The controller performance was compared using Varvel's controller performance indices. Data were compared using Fisher's exact test and the Mann-Whitney U test, P \ 0.05 showing statistical significance. Results In the Closed-loop group, four females and 16 males (aged 54 ± 20 yr; weight 79 ± 7 kg) underwent anesthesia lasting 143 ± 57 min. During 55%, 29%, 9%, and 7% of the total anesthesia time, the system showed excellent, good, poor, and inadequate control, respectively. In the Control group, five females and 15 males (aged 59 ± 16 yr; weight 75 ± 13 kg) underwent anesthesia lasting 157 ± 81 min. Excellent, good, poor, and inadequate control were noted during 33%, 33%, 15%, and 19% of the total anesthesia time, respectively. In the This work was presented as an abstract at the annual meeting of the Society of Technology in Anesthesia in San Diego in January 2008. The abstract won the Excellence in Technology Innovation Award. Dr. Hemmerling is the inventor of the McSleepy(R) system, which is an automated system that integrates all three components of anesthesia -hypnosis, analgesia, and muscle relaxation. This system is patent pending; however, the ''loop'' for propofol administration within McSleepy is different from the propofol administration loop used in the present manuscript. Closed-loop group, excellent control of anesthesia occurred significantly more often (P \ 0.0001), and poor and inadequate control occurred less often than in the Control group (P \ 0.01). The median performance error and the median absolute performan...

Coordinated semi‐adaptive closed‐loop control for infusion of two interacting medications

“…There is an increasing interest in computerized closed-loop control of medication infusion for critically ill patients by virtue of its potential for delivery and continuous monitoring of high-quality treatment [1][2][3] and alleviation of caregivers' workload. 4,5 Indeed, closed-loop control of anesthesia, [6][7][8] vasopressor infusion, 9 and fluid resuscitation [10][11][12] has been an active area of research for a few decades.…”

Target-controlled infusion devices: are we missing much?

“…Some systems have been developed, but they are not widely available. [7][8][9] In practice, however, depth of anesthesia is not adjusted according to just one variable, but rather to a constellation of factors, such as the hemodynamic state of the patient, the anticipated stimuli, and past response to the same drugs. Users of TCI devices will either increase or decrease the ''target concentration'' in response to perceived under-or over-dosing, respectively.…”

“…Certains systèmes ont été mis au point mais ils sont peu disponibles. [7][8][9] Dans la pratique toutefois, la profondeur de l'anesthésie n'est pas ajustée en fonction d'une seule variable, mais plutôt d'une myriade de facteurs tels que l'état hémodynamique du patient, les stimuli anticipés, et des effets antérieurs des mêmes médicaments. Les utilisateurs de dispositifs d'AIVOC augmenteront ou au contraire réduiront la « concentration cible » en réponse à un sous-dosage ou à un surdosage, respectivement.…”

Automated control of anesthesia ten years later: futuristic novelty or present day reality

“…The manuscript by Hemmerling et al in this issue of the Journal certainly forces us to consider whether relinquishing control would be a viable option for providing anesthesia. 2 Our understanding of the nature of anesthesia and our ability to measure at least a component of the anesthetic state have evolved over the past 15 years. Seminal work by Rampil 3,4 and Antognini 5 has contributed enormously to our knowledge of the anesthesia paradigm.…”

“…nous pousse à réflexion: serait-ce une option viable que de céder la surveillance lors de la fourniture d'une anesthésie? 2 Au cours des quinze dernières années, notre compréhension de la nature de l'anesthésie et notre capacité à mesurer au moins une composante de l'état anesthésique ont évolué. Les travaux précurseurs de Rampil 3,4 et Antognini 5 ont apporté une contribution majeure à nos connaissances de ce paradigme de l'anesthésie.…”