Semester of Graduation

Fall 2018


Master of Science in Mechanical Engineering (MSME)


Mechanical and Industrial Engineering

Document Type



Anesthesia is used to sedate both humans and animals for surgery. In veterinary practice, breathing systems are often used to supply anesthetic gas to the patient. Occasionally, a large amount of pressure can build up in the breathing circuit. This high pressure, if unnoticed, can lead to fatal injury to the lungs of the veterinary patient. The maximum allowable pressure in the anesthetic circuit for small animals is 25 cmH2O or 2450 Pa. As such, it is necessary to monitor oxygen flow rate (ranging from 0.1-4 LPM), pressure, oxygen rate, anesthetic composition, among other variables during an operation. Currently, not all veterinary anesthesia machines are equipped with a reliable way of detecting and relieving gas when dangerous pressures are reached. This thesis aims to understand veterinary anesthesia circuits and pressure relief systems and to formulate a Simscape Fluids model with components representative of real anesthesia machine components. The model was used to simulate the response of two commercially-available safety devices, the EMD Valve and Reverse-PEEP Valve, attached to the anesthesia system under various operating conditions. It was found that the Reverse-PEEP Valve is more effective at preventing lung injury to veterinary patients.



Committee Chair

de Queiroz, Marcio