System Design Verification for Closed Loop Control of Oxygenation With Concentrator Integration

Abstract

BACKGROUND:

Addition of an oxygen concentrator into a control loop furthers previous work in autonomous control of oxygenation. Software integrates concentrator and ventilator function from a single control point, ensuring maximum efficiency by placing a pulse of oxygen at the beginning of the breath. We sought to verify this system. Methods: In a test lung, fraction of inspired oxygen (FIO2) levels and additional data were monitored. Tests were run across a range of clinically relevant ventilator settings in volume control mode, for both continuous flow and pulse dose flow oxygenation. Results: Results showed the oxygen concentrator could maintain maximum pulse output (192 mL) up to 16 breaths per minute. Functionality was verified across ranges of tidal volumes and respiratory rates, with and without positive end-expiratory pressure, in continuous flow and pulse dose modes. For a representative test at respiratory rate 16 breaths per minute, tidal volume 550 mL, without positive end-expiratory pressure, pulse dose oxygenation delivered peak FIO2 of 76.83 ± 1.41%, and continuous flow 47.81 ± 0.08%; pulse dose flow provided a higher FIO2 at all tested setting combinations compared to continuous flow (p < 0.001). Conclusions: These tests verify a system that provides closed loop control of oxygenation while integrating time-coordinated pulse-doses from an oxygen concentrator. This allows the most efficient use of resources in austere environments.

METHODS:

In a test lung, fraction of inspired oxygen (FIO2) levels and additional data were monitored. Tests were run across a range of clinically relevant ventilator settings in volume control mode, for both continuous flow and pulse dose flow oxygenation.

RESULTS:

Results showed the oxygen concentrator could maintain maximum pulse output (192 mL) up to 16 breaths per minute. Functionality was verified across ranges of tidal volumes and respiratory rates, with and without positive end-expiratory pressure, in continuous flow and pulse dose modes. For a representative test at respiratory rate 16 breaths per minute, tidal volume 550 mL, without positive end-expiratory pressure, pulse dose oxygenation delivered peak FIO2 of 76.83 ± 1.41%, and continuous flow 47.81 ± 0.08%; pulse dose flow provided a higher FIO2 at all tested setting combinations compared to continuous flow (p < 0.001).

CONCLUSIONS:

These tests verify a system that provides closed loop control of oxygenation while integrating time-coordinated pulse-doses from an oxygen concentrator. This allows the most efficient use of resources in austere environments.

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Authors: Thomas C. Blakeman (a) , Jay A. Johannigman (a,b), Matthew M. Gangidine (a,b), Richard D. Branson (a)
(a) University of Cincinnati Department of Surgery, Division of Trauma/Critical Care; Cincinnati, OH, United States
(b) Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814.

System Design Verification for Closed Loop Control of Oxygenation With Concentrator Integration (pdf)

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