<p>Comparison of Respiratory Variations of Subclavian Vein and Inferior Vena Cava in Hospitalized Patients with Kidney Disease</p>

Abstract

Background Accurate assessment of relative intravascular volume is critical for appropriate volume management of patients with kidney disease. Respiratory variations of inferior vena cava (IVC) diameter have been used and may correlate with those of subclavian vein (SCV) by bedside ultrasound. The purpose of this study was to assess the relationship between SCV and IVC respiratory variations by bedside ultrasound in a large group of hospitalized patients with acute and/or chronic kidney disease. Methods We compared 160 paired SCV and IVC bedside ultrasound studies from 102 semi-recumbent hospitalized adult patients with kidney disease. Patient encounters in which the SCV or IVC could not be clearly visualized were excluded. Collapsibility index=(Dmax–Dmin)/Dmax*100%; D=venous diameter. Results Relationships between SCV collapsibility index and IVC collapsibility index were not different for longitudinal and transverse views of the SCV. Correlation of SCV collapsibility index with IVC collapsibility index was 0.75 for mechanical ventilation (n=65, P<0.0001) and 0.67 for spontaneous breathing (n=95, P<0.0001). IVC collapsibility index cut-offs <20% for hypervolemia and >50% for hypovolemia corresponded to SCV collapsibility index cut-offs of <22% and >39%, respectively, for both mechanical ventilation and spontaneous breathing encounters. Using these cut-offs for SCV collapsibilities, assessment as hypervolemia versus not-hypervolemia had maximal sensitivity and specificity for predicting respective IVC collapsibility cut-offs of 88% for mechanical ventilation and 74% for spontaneous breathing, and assessment as hypovolemia versus not-hypovolemia had maximal sensitivity and specificity of 91% and 70%, respectively. Concordance, defined as agreement between assessment using SCV CI and assessment using IVC CI, was 85% for mechanical ventilation and 72% for spontaneous breathing when differentiating hypervolemia versus not-hypervolemia and was 89% and 71% respectively when differentiating hypovolemia versus not-hypovolemia. Conclusion Assessment using SCV collapsibility index in the semi-recumbent position has a reasonable concordance with assessment using IVC collapsibility index for both spontaneous breathing and mechanical ventilation, in a wide range of hospitalized patients with concurrent kidney disease, and may be a useful adjunct to assess relative intravascular volume in patients with kidney disease.

Comparison of subclavian vein to inferior vena cava collapsibility by ultrasound in acute heart failure: A pilot study

“…The correlation between SCV CI and IVC CI in our population is similar to other studies of spontaneously breathing patients, positioned supine at 30–45°. Our correlation ( R = .65, n = 36) was similar to patients hospitalized with acute and chronic renal failure ( R = .67, n = 95) 23 and patients undergoing echocardiography ( R = .69, n = 39) 22 . The relationship of SCV CI to IVC CI in patients undergoing echocardiography has been shown to be inferior when SCV CI was measured supine at 0° 22 .…”

“…Based on prior studies, IVC CI > 50% and <20% have been shown to correspond to RAP by right heart catheterization of <5 mmHg and >20 mmHg, respectively 16,23 . Sensitivity and specificity of SCV CI cutoffs predicting these specific IVC CI cutoffs are shown in Figure 4.…”

“…22 Assessment of SCV CI, as with physical examination of JVP, is highly position-dependent and should be performed supine at 30-45°. 22,23 On the other hand, there are no differences for IVC max or IVC CI when measured at 0°versus 45°. 33 Our SCV CI cutoff of <22% which best predicted an IVC CI cutoff <20% suggesting hypervolemia (sensitivity/specificity 72%), is similar In a study of 96 patients with severe TR, those with signs of rightsided congestive heart failure had lower IVC CI (mean ± SD:…”

“…The probe was placed inferior to the lateral border of the right clavicle, aligned in the deltopectoral groove along the axis of the right arm to obtain a transverse view of the SCV at the junction of the proximal axillary vein (Figure 1A). 21,23,24 The IVC was imaged via the subcostal window in a longitudinal plane using the phased array transducer (Figure 1A). For both IVC and SCV, maximum ( D max ) and minimum ( D min ) diameters were measured with both relaxed breathing and forced inspiration or “sniff.” A frame‐by‐frame analysis of greyscale (B‐Mode) images was performed to identify D max and D min , which were then measured using the digital calipers (GE Healthcare) (Figures 1B,C).…”

“…12 SCV CI measured in patients reclining at 30-45°correlated well with subcostal IVC CI in patients undergoing echocardiography, 22 in patients treated in the surgical intensive care unit 21 and in those hospitalized with acute and/or chronic renal failure. 23 SCV CI has not previously been compared to IVC CI in patients hospitalized with acute congestive heart failure.…”