Stefan Candefjord och Rubén Buendía

Bioimpedance technology for detection of thoracic injury published in scientific journal

Stefan Candefjord and Rubén Buendía at MedTech West

In October 2017 an article by the MedTech West researchers Rubén Buendía and Stefan Candefjord was published in the scientific journal Physiological Measurement. The partners in this project are SAFER/Chalmers, Sahlgrenska University Hospital and the University of Borås. The other authors are Benjamin Sanchez, Harvard Medical School, Bengt-Arne Sjöqvist, Professor at Chalmers University of Technology, and Hans Granhed, Per Örtenwall and Eva-Corina Caragounis, trauma surgeons at Sahlgrenska University Hospital. The title of the paper is Bioimpedance technology for detection of thoracic injury.

A picture of trauma surgeon Eva-Corina Caragounis


“Thoracic trauma is one of the most common types of injury and directly accounts for a quarter of trauma-associated mortality, says trauma surgeon Eva-Corina Caragounis. “Early deaths can be due to bleeding or air leakage causing tension pneumothorax. Patient examination in the pre-hospital setting can be challenging, but the correct diagnosis and treatment can be lifesaving. Although ultrasound is available for pre-hospital doctors, the technique requires training and experience. There is therefore a need of a point-of-care diagnostic device that requires less training and is non-operator dependent”.

Electrical bioimpedance (EBI) is non-invasive, portable, rapid and easy to use technology that can provide objective and quantitative diagnostic information for the prehospital environment. In this project we evaluated the performance of EBI to detect thoracic injuries. EBI resistance (R), reactance (X) and phase angle (PA) of both sides of the thorax were measured at 50 kHz on patients suffering from thoracic injuries (n  =  20). In parallel, a control group consisting of healthy subjects (n  =  20) was recruited. A diagnostic mathematical algorithm, fed with input parameters derived from EBI data, was designed to differentiate patients from healthy controls.

The study showed that ratios between the X and PA measurements of both sides of the thorax were significantly different (p  <  0.05) between healthy volunteers and patients with left- and right-sided injuries. The diagnostic algorithm achieved a performance evaluated by leave-one-out cross-validation analysis and derived area under the receiver operating characteristic curve of 0.88. A diagnostic algorithm that accurately discriminates between patients suffering thoracic injuries and healthy subjects was designed using EBI technology. A larger, prospective and blinded study is thus warranted to validate the feasibility of EBI technology as a prehospital tool.

Read the scientific article>>