Vibration response imaging (VRI) measures vibration response energy generated from airflow, to create a radiation free, dynamic, real-time structural and functional image of the respiration process. VRI technology records airflow generated vibrations reaching the chest surface using a set of 42 ultra high-frequency microphones that are attached to the patient’s back (Figure 1). Using custom-designed software the signals are fitted to a mathematical function and a gray level frame is constructed. VRI is designed to capture images not attainable by other lung imaging technology. In the critically ill patient, VRI may facilitate diagnosis and management of critically ill patients such as intrathoracic assessment of flow as well as response to bedside interventions.
Case 1 –A 55-year-old male patient admitted to the intensive care unit (ICU) following exploratory laparotomy was mechanically ventilated. He was found to have significant auto-PEEP. The VRI technology allowed assessment of intensity of expiratory flow (Figure 2, arrow demonstrates continued end expiratory vibration signal extending into next inspiration). Case 2 –A 51-year-old male patient was admitted to the ICU with respiratory failure. Following extubation major left lung atelectasis was present. VRI images during inspiration at maximal flow demonstrated improvement of ventilatory distribution to left lung following incentive spirometry compared to distribution at baseline inspiration. (Figures 3 & 4).
The cases above demonstrate the potential for non-invasive quantification of end expiratory flow and impact of incentive spirometry on distribution of flow.
VRI provides real time non-invasive acoustic lung imaging allowing documentation of both spatial distribution and quantification of airflow. It may potentially offer significant diagnostic and treatment value to patient management in the ICU.
Susmita Rajanala, None.