Evaluation of a novel closed-loop fluid-administration system based on dynamic predictors of fluid responsiveness: an in silicosimulation study

Tavernier Benoît, Rinehart Joseph, Alexander Brenton, Manach Yannick, Hofer Christoph, Kain, Cannesson, Cannesson Maxime

Description

Dynamic predictors of fluid responsiveness have made automated management of fluid resuscitation more practical. We present initial simulation data for a novel closed-loop fluid-management algorithm (LIR, Learning Intravenous Resuscitator). Methods The performance of the closed-loop algorithm was tested in three phases by using a patient simulator including a pulse-pressure variation output. In the first phase, LIR was tested in three different hemorrhage scenarios and compared with no management. In the second phase, we compared LIR with 20 practicing anesthesiologists for the management of a simulated hemorrhage scenario. In the third phase, LIR was tested under conditions of noise and artifact in the dynamic predictor. Results In the first phase, we observed a significant difference between the unmanaged and the LIR groups in moderate to large hemorrhages in heart rate (76 ± 8 versus 141 ± 29 beats/min), mean arterial pressure (91 ± 6 versus 59 ± 26 mm Hg), and cardiac output (CO; (6.4 ± 0.9 versus 3.2 ± 1.8 L/min) ( P < 0.005 for all comparisons). In the second phase, LIR intervened significantly earlier than the practitioners (16.0 ± 1.3 minutes versus 21.5 ± 5.6 minutes; P < 0.05) and gave more total fluid (2,675 ± 244 ml versus 1,968 ± 644 ml; P < 0.05). The mean CO was higher in the LIR group than in the practitioner group (5.9 ± 0.2 versus 5.2 ± 0.6 L/min; P < 0.05). Finally, in the third phase, despite the addition of noise to the pulse-pressure variation value, no significant difference was found across conditions in mean, final, or minimum CO. Conclusion These data demonstrate that LIR is an effective volumetric resuscitator in simulated hemorrhage scenarios and improved physician management of the simulated hemorrhages.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2011
• Nombre de lectures: 6
• Langue: English

Extrait

Rinehartet al.Critical Care2011,15:R278 http://ccforum.com/content/15/6/R278

R E S E A R C HOpen Access Evaluation of a novel closedloop fluid administration system based on dynamic predictors of fluid responsiveness: anin silico simulation study 1 12,3 45 1 Joseph Rinehart , Brenton Alexander , Yannick Le Manach, Christoph K Hofer , Benoit Tavernier , Zeev N Kain 1* and Maxime Cannesson

Abstract Introduction:Dynamic predictors of fluid responsiveness have made automated management of fluid resuscitation more practical. We present initial simulation data for a novel closedloop fluidmanagement algorithm (LIR, Learning Intravenous Resuscitator). Methods:The performance of the closedloop algorithm was tested in three phases by using a patient simulator including a pulsepressure variation output. In the first phase, LIR was tested in three different hemorrhage scenarios and compared with no management. In the second phase, we compared LIR with 20 practicing anesthesiologists for the management of a simulated hemorrhage scenario. In the third phase, LIR was tested under conditions of noise and artifact in the dynamic predictor. Results:In the first phase, we observed a significant difference between the unmanaged and the LIR groups in moderate to large hemorrhages in heart rate (76 ± 8 versus 141 ± 29 beats/min), mean arterial pressure (91 ± 6 versus 59 ± 26 mm Hg), and cardiac output (CO; (6.4 ± 0.9 versus 3.2 ± 1.8 L/min) (P< 0.005 for all comparisons). In the second phase, LIR intervened significantly earlier than the practitioners (16.0 ± 1.3 minutes versus 21.5 ± 5.6 minutes;P< 0.05) and gave more total fluid (2,675 ± 244 ml versus 1,968 ± 644 ml;P< 0.05). The mean CO was higher in the LIR group than in the practitioner group (5.9 ± 0.2 versus 5.2 ± 0.6 L/min;P< 0.05). Finally, in the third phase, despite the addition of noise to the pulsepressure variation value, no significant difference was found across conditions in mean, final, or minimum CO. Conclusion:These data demonstrate that LIR is an effective volumetric resuscitator in simulated hemorrhage scenarios and improved physician management of the simulated hemorrhages.

Introduction Automation is ubiquitous in modern life but historically has found limited application in medical care. However, recent interest has led to the rapid growth of research in automated controllers in areas ranging from glucose management to sedation to mechanical ventilation (13). Closedloop (automated) controllers have been shown to manage patients safely and more consistently than

* Correspondence: [e-mail] 1 Department of Anesthesiology & Perioperative Care, University of California, Irvine 101 S City Drive, Orange, CA 92868, USA Full list of author information is available at the end of the article

clinicians for myriad applications [13], but a key requirement for proper function is reliable feedback data from systems being controlled. In the case of fluid responsiveness, historical measures like urine output, central venous pressure, and pulmonary capillary wedge pressure are very poor predictors and thus unsuitable for use in a closedloop system [4]. Fortunately, great progress has been made in two areas that now make automated fluid management prac tical [5]. The first is the description and characterization of the dynamic predictors of fluid responsiveness. Para meters like pulsepressure variation (PPV), stroke

© 2011 Cannesson et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.