Abstract

Background: Although researchers have investigated the puffing behavior of tobacco products, no attempt has yet been made to observe both puffing and respiratory behaviors simultaneously in the natural use environment. Observation of puffing behavior alone is insufficient for predicting the health effects of tobacco use, as it can only be used to estimate the amount of emissions generated and transferred to the oral cavity. Respiration behavior must be observed for the estimation of delivery and retention of nicotine and other HPHCs in the lungs. Parameters that quantify respiratory behavior include inhalation and exhalation volumes, flow rates, and durations, as well as breath-hold duration. Researchers are presently limited by the lack of a viable non-invasive ambulatory monitoring technique for simultaneous monitoring of puffing and respiratory behavior. Methodologies: The primary focus of this work is in adapting a commercially-available Wearable Respiratory Monitor (WRM) to measure quantitative respiratory parameters. These devices normally only report basic metrics such as respiratory-rate. They are, however, equipped with sensors that track chest motion which can be used to infer respiratory volume via calibration. Nine commercial WRMs were identified. By employing a selection criteria, three WRM candidates were acquired for extensive characterization using a purpose-built chest expansion simulator. To measure puffing parameters, the previously validated and deployed wPUM topography monitor was used. Parameters based on puffing and respiratory behaviors were proposed for quantifying the specific puffing and inhalation patterns of "Mouth-to-Lung" (MTL) and "Direct-to-Lung" (DTL). A method was developed to synchronize the data collected from the Hexoskin to that of the wPUM to account for discrepancies in their real-time clocks. Data processing tools were developed to perform the various analyses and signal processing tasks. Results: The Hexoskin Smart Garment was determined to be the most suitable WRM. The device was successfully calibrated and although the calibration parameters showed some variability across repeated trials, the overall impact of this on the measurement of respiratory volume was determined to be relatively low. The Hexoskin was validated against a spirometer and was found to have good accuracy and repeatability. Respiratory parameters were calculated from data collected over a period of 12 hours (over 10,000 breaths) in the natural environment. The time synchronization method proved to be effective at eliminating the time discrepancy between the Hexoskin and the wPUM monitor. The combined system was able to find puff associated respiratory cycles from participant data. Application: This combined system has been deployed in two studies to help assess the influence of tobacco product characteristics, specifically flow path resistance and nicotine strength on puffing and respiratory behavior. Previous research suggest that users of products with high flow path resistance, such as cigarettes, are more likely to exhibit MTL behavior whereas users of products with low flow path resistance, such as hookah, are more likely to exhibit DTL behavior. A reduction in nicotine strength may cause users to perform compensatory behaviors, such as taking larger inhale volumes and holding their breaths for longer. The system, with some improvements, would be useful to the tobacco research community.

Publication Date

7-26-2022

Document Type

Dissertation

Student Type

Graduate

Degree Name

Engineering (Ph.D.)

Department, Program, or Center

Engineering (KGCOE)

Advisor

Risa Robinson

Advisor/Committee Member

Edward Hensel

Advisor/Committee Member

Stephanie Godleski

Campus

RIT – Main Campus

Share

COinS