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Point-of-care ultrasonography (POCUS) has emerged as an important tool for examining critically ill patients. POCUS devices have become progressively smaller and more accessible, transforming medical practice and reducing costs. One technological breakthrough was the development of ultraportable scanners with microchip technology, which utilize a probe connected to a smartphone or tablet and incorporate a mobile application that employs artificial intelligence to assist in the interpretation of acquired images.
Objective: To compare the accuracy of ultrasound microchip technology with traditional piezoelectric crystal ultrasonography, we analyzed two volume status parameters in ICU patients with acute kidney injury receiving kidney replacement therapy (KRT). These were the assessment of extravascular pulmonary water (lung B-lines) and the inferior venous collapsibility Index (IVCi).
Fifty critically ill patients met the study criteria. Lung POCUS quantified B-lines in eight quadrants. The IVCi was measured using the maximum and minimum diameters during a respiratory cycle. Both technologies were sequentially employed in a randomized fashion to acquire the parameters at two different time points: before the initiation of KRT and 60 minutes after the procedure had commenced. We calculated the correlation and agreement between the two ultrasound scanner modalities.
The correlation between the two technologies for evaluating lung B-lines showed strong positive coefficients, ⍴=0.96 and ⍴=0.93 at T0and T60, respectively (P<0.001 for both). The correlation for IVCi was ρ=0.70 and ρ=0.87 at TO and T60, respectively (P<0.001 for both). The Bland-Altman plots showed agreement between ultrasound methods for IVCi calculation and B-line quantification. For IVCi calculation at T0, bias was +2.69 (SD 10.6), 95% CI [-18.13 to +23.52]. At T60, bias was 3.28 (SD 10.23), CI [-16.77 to +23.34] and for B-line quantification the analysis yielded a Bias of -0.3 (SD 2.73), with a 95% confidence interval of [-5.66 to +5.06] at T0, and a Bias of 0.2 (SD 3.23), with a confidence interval of [-6.14 to +6.54 at T60.
Our study observed a good correlation and agreement between microchip and piezoelectric-based ultrasound modalities in evaluating the presence of pulmonary B-lines and IVC dynamics in patients with acute kidney injury. Along withportability, ease of use, and cost-effectiveness, microchip US reliably provides bedside parameters for volume assessment, comparable to those obtained with POCUS performed with conventional with piezoelectric transducer-based ultrasonography