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FIx controller: an instrument to automatically adjust inspired oxygen fraction using feedback control from a pulse
D B Raemer1, X B Ji, G P Topulos
1Department of Anesthesia, Massachusetts General Hospital, Boston 02114, USA.
Journal of Clinical Monitoring
|March 1, 1997
Summary
A new device was developed to prevent pulmonary oxygen toxicity in intensive care patients by automatically controlling fraction of inspired oxygen (FIO2) based on pulse oximetry (SpO2). Animal testing showed promising results for the automated FIO2 control system.
Area of Science:
- Biomedical Engineering
- Critical Care Medicine
- Respiratory Physiology
Background:
- Pulmonary oxygen toxicity is a serious complication in adult intensive care patients requiring supplemental oxygen.
- Current methods for managing fraction of inspired oxygen (FIO2) can be manual and may not prevent toxicity.
- Automated control systems offer a potential solution for precise FIO2 delivery.
Purpose of the Study:
- To develop and test a novel instrument for preventing pulmonary oxygen toxicity.
- To create a closed-loop system that automatically adjusts FIO2 based on real-time patient oxygen saturation.
Main Methods:
- Designed, built, and tested a device controlling FIO2 using pulse oximetry (SpO2) in a negative feedback loop.
- Implemented a conservative artifact rejection algorithm, a gain-scheduled PID controller, and a safety system.
- Tuned the control system in animal experiments and tested algorithms via simulation.
Main Results:
- The automated FIO2 control system demonstrated acceptable clinical response in animal experiments.
- A gain-scheduled controller algorithm effectively adjusted FIO2 based on error signals and minute ventilation.
- Artifact rejection and safety systems were successfully validated through simulation.
Conclusions:
- The developed instrument shows potential for preventing pulmonary oxygen toxicity in intensive care settings.
- Further clinical trials comparing this automated system to manual FIO2 control are necessary to confirm effectiveness.