Wireless monitoring of post-operative respiratory complications

Respiratory complications may occur in post-operative patients but are often difficult to detect due to the lack of a well-tolerated and reliable monitoring method. We have developed a wireless accelerometer-based device that measures chest wall rotations due to breathing and has been shown to provide an accurate measure of respiratory rate in a clinical setting, when validated against rates obtained from nasal pressure. This paper describes a method for detecting instances of respiratory problems due to physical airway obstruction and central nervous system (CNS) respiratory depression using a combination of nasal pressure and chest wall rotation signals in gynaecological patients during the first night after surgery. Waxing and waning of breath amplitude and irregularity of breath length are found to be useful indicators. A clinical study involving 19 post-operative patients shows that the proposed method is able to detect and distinguish between both forms of respiratory complications.