Lung Inhomogeneity Is an Early Indicator of Acute Lung Injury

It is estimated that acute lung injury (ALI) occurs in 200,000 people in the US each year and is associated with 75,000 deaths. Diagnostic criteria for ALI include large decreases in arterial oxygenation and lung compliance. Clinical indicators occur late in ALI pathogenesis, once significant lung damage has occurred. Identifying ALI earlier in its pathogenesis may allow for interventions that minimize lung injury. We hypothesized that the use of noninvasive vibrational resonance imaging (VRI™Deep Breeze, Inc.) would identify lung dysfunction before the development of clinically recognizable ALI. METHODS ALI was induced in an anesthetized pig with a peritoneal fecal clot and clamping the SMA for 30 minutes. Multiple VRI recordings were obtained throughout the 48 hr study (Figure 1). RESULTS The VRI homogeneity of the lungs decreased rapidly over the first 12 hrs, however ALI was not clinically evident until 42 hrs post injury as evidenced by a P/F ratio < 300 (Figure 2). There was no decline in lung homogeneity or P/F ratio in a control experiment (Figure 3). CONCLUSIONS In this case study, there were detectable changes in lung homogeneity 30 hrs prior to clinically measurable ALI. VRI may identify patients early in the disease process, long before clinical parameters, giving physicians the ability to intervene and alter the course of ALI or prevent it altogether.