Development of a Canine Model for the Study of Obstructive Sleep Apnea

1. Development of a Canine Model for the Study of Obstructive Sleep Apnea Geeta Vanketesh, Department of Chemistry, Oakland University; Liliya Goroshko, Department of Biomedical Engineering, University of Akron; Hamza Osto, Department of Biology, U of M Dearborn; Timothy Fritzsching, Department of Computer Engineering, University of Akron; Dr. Osamah Rawashdeh, Department of Electrical and Computer Engineering, Oakland University; Dr. Robert Hammond, Department of Surgery, William Beaumont Hospital Introduction Design Overview Occlusion Device – Using Linear Actuator Different Sleep Phases Sleep apnea is a breathing disorder characterized by a reduction or cessation of breathing during sleep. There are three types of apnea: 1. Central sleep apnea (CSA) 2. Obstructive sleep apnea (OSA) 3. Mixed sleep apnea (MSA) OSAis the most common form of sleep apnea in which the airway is occluded. Nearly 18 million Americans are estimated to be affected by OSA. Approximately 1 in 5 adults is affected by mild obstructive sleep apnea (OSA) and 1 in 15 adults has OSA of moderate or worse severity (Journal of the American Medical Association). The consequences of Obstructive Sleep Apnea range from disruptive to life-threatening. Disruptive consequences include daytime fatigue, depression, irritability, sexual dysfunction, and memory loss. Life-threatening consequences include congestive heart failure, stroke, irregular heart rhythms, cardiovascular disease and fatal car accidents. OSA is becoming more prevalent due to increase in obesity, diabetes, stress, and alcohol consumption. The lack of an animal model to study this disorder has hindered the further understanding of its causes and effects. A suitable canine model that allows researchers to induce sleep apnea episodes and monitor short and long term effects can serve as a data engine for medical researchers to learn more about this serious and spreading problem. There are five stages of sleep phases in a sleep cycle in human /animal. The REM sleep phase is the one when throat muscles relaxes completely and occurrence of sleep apnea is most. The OSA is induced in REM sleep phase for laboratory purpose. In a flap-shaped valve, the percentage of occlusion is linearly proportional to the distance and allows more consistent control of airflow. Whereas, in a cone-shaped valve, the percentage of occlusion is non-linearly proportional to its position. (Note, the sphere-shaped valve would act similarly to the cone-shaped valve, except that the parabola is more drastic for the sphere. Future Work • To develop a device for detecting different sleep phases, and to detect when the animals reaches Rapid Eye Movement phase (REM) to induce OSA , • Miniaturizing the system to make it collar mounted, • And to install Fail Safe mechanism, so that if the pressure falls bellow a certain value, then a valve will rupture and the dog will be able to breath. • Data collection for researchers. Accuracy measurements of Actuator Goal Ethical Issues • Why are we using animals to conduct this research? • Performing sleep study on humans is unethical, so inducing OSA in an animal is a viable alternative due to ethical considerations, moral issues, and liability. • Other alternatives have been evaluated, but using a canine model is the best choice. • Why are we using a dog for this experiment? • The canine model would accurately parallel future responses in humans, with minor adjustments. • The physiology of a canine is most suitable for our experiment because of its: • collateral circulation (its biological systems are tolerant to testing without harm); • good body size; • interaction and sociability make canines easier to adapt to the laboratory environment; • longevity allows for long-term study. The goal of this project is to develop a device that will mimic the effects of Obstructive Sleep Apnea by occluding the airway. OSA is induced by occluding the airway to different degrees and intervals depending on sleep phases. The vital statistical data is acquired from this study including changes in the blood flow velocity, blood pressure, body temperature change, oxygen saturation, metabolic rate, and brain waves. User Interface The user inputs the amount of occlusion through the hyper terminal which is passed to the HCS12 microcontroller by serial communication interface. Microcontroller (HCS12) The microcontroller takes the input from the hyper terminal and adjusts the linear actuator to the desired occlusion of the airway. Actuator A motorized device to control the opening and closing of the airflow in the tube. Transceiver This allows for wireless communication between the system attached to the dog and the user interface.  Trachea Tube The tube is implanted into the dog’s trachea, which serves as a medium for the occlusion process.  Cohort of 2009 Results and Conclusions • We have produced a successful method to occlude the airway by using an airflow control system. A researcher can control the degree of occlusion via hyper terminal. • A wireless transceiver is used to remotely control the collar mounted unit. • The various degrees of occlusion will allow researchers to accurately mimic the long term and short term effects of sleep apnea. • In addition to the production of the actuator and the valve system, we have outlined a procedure for the placement of the valve, actuator, and trachea tubes attached to the dog. Acknowledgements This work was performed during the SIBHI program at Oakland University funded by NSF and NIH under the BBSI program (Summer Institute for Bioengineering and Bioinformatics ), grant no. 0552707. The authors would like to thank the staff of the Electronics Shop and the students in the Embedded Systems Research Lab for all their help and support.