Developing and Implementing a Digital Spirometer for Preoperative and Postoperative Patients with Chest Surgery and Abdominal Laparotomy

Abstract

Post-surgery respiratory complications are serious problems that cause a significant number of morbidities and mortalities. In countries like Ethiopia with high respiratory disease rates, the lack of digital spirometers in healthcare facilities, coupled with the absence of population-specific reference values, hinders accurate patient diagnosis. The aim of this study was to develop, implement, and analyze a digital spirometer for preoperative and postoperative elective patients with chest surgery and abdominal laparotomy. The spirometer was designed and developed based on the Ethiopian population's lung reference equation, featuring an Arduino Due microcontroller, a silicon piezoresistive differential pressure sensor (MPXV7002), a BMP180 barometric pressure sensor, and an SD card module for data storage. Testing using the device involved 80 elective patients for chest surgery or abdominal laparotomy at Jimma University Medical Center (JUMC). Spirometer variables such as FVC, FEV1, and FEV1/FVC ratio were associated with pre/postoperative assessments using RStudio. In the preoperative assessment, normal cases comprised 51.2%, and restrictive cases were at 46.2%. Postoperatively, restrictive cases increased to 55.0%, while normal cases decreased to 40.0%. Significant associations were found between spirometer results and preoperative factors such as COPD/asthma history, cough presence, chest surgery history, and smoking habit (P <0.05). Moreover, preoperative spirometer results were significantly associated with postoperative complications such as pneumonia, chest pain, shortness of breath, wheezing, fever, and cough. The study emphasizes the importance of employing a spirometer specifically designed based on the lung reference equation tailored for the Ethiopian population. However, future studies should be done using cohorts of a larger sample size, and the incorporation of a screen touch interface for the future design of the device needs to be considered.