Self-Regulating Oxygen Delivery System

1. SIBHI 2008 Self-Regulating Oxygen Delivery System Advisors Cheryl Riley-Doucet, PhD, RNOakland UniversityNursingrileydou@oakland.edu Debatosh Debnath, PhDOakland UniversityComp. Sci. & Engineeringdebnath@oakland.edu Jason Nixon Purdue University Computer Science jason@sicklines.com Lauren Ehardt University of Michigan Biomedical Engineering lcehardt@umich.edu Katelyn Klein University of Michigan Biomedical Engineering katklein@umich.edu CURRENT PROBLEMS IN OXYGEN THERAPY • National shortage of nurses [4]. • Pulse oximeter alarms not used effectively. • Lack of awareness on consequences of hyperoxygenation. • Standard oxygen prescriptions do not adequately represent a patient’s oxygen levels during a normal day [5]. PROPOSED DESIGN Electronic Proportional Valve • Parker HF Pro valve controls the flow of gas proportional to input voltage. • The valve is normally closed when no input voltage is supplied. • The valve is supplied a variable voltage by the PWM signal from the HCS12. ABSTRACT • Oxygen therapy is a common treatment for premature infants, chronic obstructive pulmonary disease, and respiratory failure. The current method used to deliver supplemental oxygen involves manual control. • Research has shown that automatic control of oxygen delivery is more effective at maintaining optimal oxygen saturation (SpO2) than manual control [1]. In addition, automatic control of oxygen delivery would ease the workload of nurses and other caregivers. • We propose a self-regulating device that adjusts the oxygen flow to a patient based on his/her present SpO2. The SpO2 is measured by pulse oximetry. This measurement is received by a microcontroller which appropriately adjusts the oxygen flow through an electronic proportional valve to a patient. • The proposed device is portable, cost effective, and user-friendly; thus it could be widely used in the hospital and at home. PICTURE OF DEVICE • The proposed device consists of a pulse oximeter sensor, oximeter board, a microcontroller, and a proportional valve. Pulse Oximeter Sensor and Board • BCI pulse oximeter sensor collects and sends data to BCI oximeter board. • BCI oximeter board calculates the SpO2 and sends a signal to the microcontroller. HCS12 PURPOSE To design a self-regulating device that automatically adjusts the oxygen flow to a patient based on the patient’s oxygen saturation reading. Signal from oximeter board and sensor Valve Oxygen Source To patient BENEFITS OF AUTOMATIC OXYGEN DELIVERY • More effective than manual control at maintaining optimal oxygen saturation [1]. • Limits fluctuations in SpO2 , thus decreasing number of hypoxic and hyper-oxygenation events. • Prevents problems associated with hyper-oxygenation including CO2 retention and retinopathy of prematurity (ROP). • Lessens workload of nurses and improves patient care. UNIQUE FEATURES • Proportional valve is only about 4% of the cost of oxygen blender, therefore lowering cost of proposed device. • Proposed device weighs less in total and is more portable than oxygen blender device. KEY FACTS • Supplemental oxygen is one of the most widely used therapies for people admitted to the hospital [2]. • One million chronic obstructive pulmonary disease (COPD) patients are on supplemental oxygen in the United States [3]. • Oxygen delivery is regulated manually by either the patient or caregiver. HCS12 Microcontroller • Communicates with BCI oximeter board via serial communication interface. • HCS12 determines whether valve opening needs to be adjusted if oxygen saturation is outside of the desired range. • HCS12 sends a voltage to the proportional valve using pulse width modulation to adjust the valve opening. REFERENCES • M. G. Iobbi, A. K. Simonds, and R. J. Dickinson, “Oximetry feedback flow control simulation for oxygen therapy,” Journal of Clinical Monitoring and Computing, vol. 21, pp. 115–123, 2007. • L. Martin, “Oxygen therapy: the first 150 years,” Mt. Sinai Medical Center, Cleveland, OH, 1999. • T. Croxton, “HLBI and CMS launch large study of home oxygen therapy for COPD,” NIH News, NHLBI Communications Office, 2006. • H. J. Goodin, “The nursing shortage in the United States of America: an integrative review of the literature,” Journal of Advanced Nursing, vol. 43, no. 4, pp. 335-350, 2003. • J. Pilling and M. Cutaia, “Ambulatory oximetry monitoring in patients with severe COPD: A preliminary study,” Chest, vol. 116, pp. 314-321, 1999. No device is currently available on the market to automatically regulate the oxygen flow to a patient.