Closed-Loop Prevention of Hypotension in the Heartbeating Brain-Dead Porcine Model

Abstract

The purpose of this paper is to demonstrate feasibility of a novel closed-loop controlled therapy for prevention of hypertension in the heartbeating brain-dead porcine model. Methods: Dynamic modeling and system identification were based on in vivo data. A robust controller design was obtained for the identified models. Disturbance attenuation properties, and reliability of operation of the resulting control system, were evaluated in vivo. Results: The control system responded both predictably and consistently to external disturbances. It was possible to prevent mean arterial pressure to fall below a user-specified reference throughout 24 h of completely autonomous operation. Conclusion: Parameter variability in the identified models confirmed the benefit of closed-loop controlled administration of the proposed therapy. The evaluated robust controller was able to mitigate both process uncertainty and external disturbances. Significance: Prevention of hypertension is critical to the care of heartbeating brain-dead organ donors. Its automation would likely increase the fraction of organs suitable for transplantation from this patient group.

Robust computation of pulse pressure variations

“…To investigate feasibility of the proposed algorithm, it was evaluated on data collected during the first of two experiments, reported in [14]. Diastolic, y d , and systolic, y s , values of a one hour section of arterial blood pressure data, sampled at 100 Hz, is shown in Figure 4a.…”

“…The data was acquired as part of a closed-loop hemodynamic stabilization project. Experimental conditions and compliance with ethical standards were reported in [14]. Details concerning study ethics are additionally found at the end of this paper, under "Compliance with ethical standards".…”

Advantage of new ventilation method for cardiopulmonary resuscitation qualitatively captured by simple respiratory mechanics models

“…A pressure transducer (DTX Plus, Argon Medical Devices, Frisco, USA) was connected to two narrow channels in the wall of the Boussignac tube through air-filled plastic tubing with non-flexible walls to measure intratracheal pressure. The transducer signal was recorded by a data aquisition system described in [17]. Due to the low-pass filtering effect of air in the pressure measurement tubes in [8], time-averaged maximum, mean, and minimum intratracheal pressure are used for comparison rather than real-time P trachea .…”

Phase-controlled intermittent intratracheal insufflation of oxygen during chest compression-active decompression mCPR improves coronary perfusion pressure over continuous insufflation

“…Individual catheters (Secalon-T-over-needle central venous catheter, 16G/1.70.130mm) for blood gas samples were inserted via direct puncture into the right carotid artery and right internal jugular vein. Catheters were also inserted into the ascending aorta and the right atrium for continuous invasive blood pressure measurement and connected to a data acquisition system (DAQ) described in [9]. A flow sensor (REF 6710; Novametrix Medical Inc., Wallingford, CT) was fitted to the proximal end of the Boussignac tube and connected to the same DAQ.…”