In silico investigation of intra-abdominal pressure monitoring by means of transient radar method; a novel non-invasive solution based on body-wave interaction

Intra-abdominal hypertension (IAH), defined as an intra-abdominal pressure (IAP) equal to or above 12 mmHg is one of the major risk factors for increased morbidity and mortality in critically ill patients. Therefore, IAP monitoring in the intensive care unit (ICU) is highly recommended to provide better patient care. The actual gold standard to measure IAP is an invasive method that carries a high risk of infection and trauma for the urinary tract. Using microwave reflectometry has been suggested as an alternative with a very promising future. In this study, the IAP monitoring via TRM, which is a sub-group of time-domain reflectometry techniques has been investigated in silico. IAH impact on the abdominal wall is simulated in this study. Subsequently, the reflection response of a computer-aided design (CAD) of the abdominal wall has been measured in different case scenarios to investigate the correlation between the reflection response of the abdominal wall and IAP elevation. Based on the obtained results, every 12 mm displacement of the AW (2 mmHg IAP elevation) towards the electromagnetic ports increases the reflection magnitude for 0.06 ± 0.02 V with a p-value of 0.0007. The thickness reduction with a step of 0.2 cm (2 mmHg IAP elevation), increases the reflection amplitude for 0.02 ± 0.005 V with a p-value of 0.05. Moreover, every 5° of curvature increase of the AW results in 0.04 ± 0.008 reflection amplitude reduction with a p-value of 0.0004.