Adaptive Breath Sampler
PhD Project

Adaptive Breath Sampler:
An Innovative Non-Invasive System for the Early Detection of Diseases

“The adaptive breath sampling system for non invasive early stage discovery of diseases through exhaled breath, made cover page on the Royal Society of Chemistry’s Chemical Biology journal” (Jan 2007)

Download the Paper

The Volatile Organic Compounds (VOC) group is renowned for its continuous innovation in sampling techniques. This was one of our breakthrough techniques in sampling technology which enabled efficient and targeted collection biomarkers through normal breathing.

Figure. Breath Sampling System Diagram; A: purified air supply, B: Pressure regulator, C: Pressure check valve, D: Mask, E: Custom made PTFE union to fit one-way valve (also see Figure 6b), F: Volatiles trap and fitting (also see Figure 6c), G: Micro-switch pneumatic valves, H: Pressure sensor, I: Programmable gain amplifier, J: Hand-held battery pump, K: Data acquisition & control PCI card.

The Problem:
The challenge was to identify the best approach to overcome certain problems inherent in breath sampling due to the existence of large amounts of water in breath and also due to the fact that individuals with impaired lung functions find it difficult to provide breath samples with the use of methodologies developed for industrial hygiene monitoring.

The Solution:
An intelligent breath sampler was developed able to adapt to different types of breathing profile and suitable for use even with patients with a heavily impaired lung function. Intelligent algorithms enable the system to sample a targeted portion of each breath cycle, which is the same even the pressure profile of one breath cycle is completely dissimilar to the next. At the same time the sampler system eliminates exogenous VOCs that can contaminate the sample.

The concept and research plan was initially presented in the 14th International Conference on Ion Mobility Spectrometry (Gatlinburg/ Tennessee, summer 2004) and was completed in early 2005. The system has successfully passed intense clinical trials and has enabled research in the early detection of health conditions which can be associated with the generation of abnormal respiration products in human lungs. The initial clinical trials were carried out with Chronic Obstructive Pulmonary Disease (COPD) patients.

Development of the instrumentation required use of both digital & analogue electronics techniques. The heart of this breath sampling system is a set of complex algorithms developed in LabVIEW. The software application written in LabVIEW carries out data acquisition and controls the digital electronics, calculates the sampled air volume, monitors the breath pressure profile and applies algorithms for the real time recognition of the useful pressure profile features. This allows the system to adapt itself in real time performing sampling during the desired portion of the breath cycle only.

Each portion of the breath cycle relates to a different depth in the lung, therefore the system enables biomarker sampling from different parts of the lung which results in increased concentration of target biomarkers and consecutively easier detection. The samples are collected in-clinic typically over a
period of ten minutes and returned to the lab for analysis by mass spectrometry.

The developed VI includes features like a) Data saving, which saves the patient information along with the acquired breath profile data, sampled volume information, volume, duration, date and time information in a Microsoft Excel file, b) saved data retrieval function for post processing purposes c) breath profile simulation tools for staff training and optimisation of operation before use c) time base setting d) gain setting which sets the gain of the onboard amplifier as required by changing the value of a digital potentiometer. Manual control is also available when required in special cases.

The approximate dimensions of the breath sampler unit are 4cm x 7cm x2cm. The unit it connects to a laptop computer through a high density SCSII cable and connector.


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