Change search
ReferencesLink to record
Permanent link

Direct link
Smartphone Capnography: Evaluation of the concept and the associated CO2 indicating sensor
KTH, School of Technology and Health (STH), Medical Engineering.
KTH, School of Technology and Health (STH), Medical Engineering.
2014 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Smartphone Capnography : Utvärdering av konceptet och den tillhörande CO2 indikerande sensorn (Swedish)
Abstract [en]

Smartphone capnography is a new concept for respiratory monitoring using a colorimetric sensor in combination with a smartphone and an Android application. Compared to using an infrared spectrophotometric carbon dioxide analyzer (IR-analyzer), the gold standard for respiratory carbon dioxide monitoring, smartphone capnography offers a cheaper and less bulky solution. This master thesis evaluates the performance of smartphone capnography and the colorimetric sensor engineered for this concept. Three different techniques (side stream, shunt stream and main stream) were tested. Additionally, an iPhone application was developed as a proof of concept when using an iPhone for smartphone capnography.


An experimental set-up simulating human breathing was assembled and measurements, at different breathing rates (6-30 breaths/min) and carbon dioxide levels (2-7vol%), were performed with an IR-analyzer as reference. Results showed that capnograms from smartphone capnography was comparable to those from the IR-analyzer and that the approximate accuracy was ±0.25vol% for up to 6 days of use. Results strongly motivate further elaboration of the concept and the three different techniques for measuring.

Abstract [sv]

”Smartphone capnography” är ett nytt koncept för att monitorera andning. Principen är en kombination av en kolorimetrisk sensor, en smartphone samt en Androidapplikation. Jämfört med den dominerande tekniken, en IR-spektrofotometrisk koldioxidanalysator (IR-analysator), så är “smartphone capnography” både billigare och mindre skrymmande. Detta examensarbete utvärderar konceptet ”smartphone capnography” och en kolorimetrisk sensor speciellt utvecklad för ändamålet. Tre olika tekniker (side stream, shunt stream och main stream) har utvärderats. Slutligen utvecklades en iPhoneapplikation för att visa att konceptet ”smartphone capnography” kan användas även med denna typ av smartphone.


Utvärderingen bestod i att göra mätningar i en experimentell uppställning som simulerar andning. Mätningar gjordes vid varierande andningsfrekvenser (6-30 andetag/min) och koldioxidnivåer (2-7vol%). Mätdata från ”smartphone capnography” jämfördes med mätdata från en IR-analysator. Resultaten visar att kapnogram från ”Smartphone capnography” är jämförbara med kapnogram från IR-analysatorn och att den uppskattade noggrannheten är ±0,25vol% för upp till 6 dagars användning. De goda resultaten motiverar fortsatt utveckling av konceptet smartphone capnography samt de olika mätteknikerna.

Place, publisher, year, edition, pages
2014. , 116 p.
Keyword [en]
capnography, smartphone, carbon dioxide, monitoring of breathing
Keyword [sv]
kapnografi, smartphone, koldioxid, monitorering av andning
National Category
Medical Engineering
URN: urn:nbn:se:kth:diva-152640OAI: diva2:750711
Subject / course
Medical Engineering
Educational program
Master of Science in Engineering - Medical Engineering
Available from: 2014-09-29 Created: 2014-09-29 Last updated: 2014-09-29Bibliographically approved

Open Access in DiVA

fulltext(2883 kB)239 downloads
File information
File name FULLTEXT01.pdfFile size 2883 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Medical Engineering
Medical Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 239 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 299 hits
ReferencesLink to record
Permanent link

Direct link