ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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We have previously reported that the maximal inferior vena cava (IVC) diameter during quiet expiration (IVCe) measured by ultrasonography correlates well with the amount of body fluid, especially the circulating blood volume(2) and proposed using the criteria of IVC diameter to determine dry weight (DW) in anuric hemodialyzed (HD) patients: standard IVCe of pre- and post-HD are 14.9 +/- 0.4 and 8.2 +/- 0.3 mm, respectively (1). However, the same post-HD IVC criterion should not be applied to nonoliguric HD patients because it could result in rapid deterioration of residual renal function due to forced dehydration. Although the biochemical DW marker plasma atrial natriuretic peptide (ANP) is useful to evaluate hypervolemia but not hypovolemia, both hyper- and hypovolemia can be detected by IVC measurement. ⋯ Although the post-HD IVCe was greater (i.e., less hypovolemic) than that in anuric HD patients, and close to the IVCe in CP-CRF, pre-HD IVCe was comparable with that in anuric HD patients. In addition, the pre-HD ANP level was no higher than that in CP-CRF. Thus, in NO-HD patients, the post-IVCe of 11.9 +/- 0.9 mm would be a marker for an appropriate DW setting avoiding severe post-HD dehydration as well as excessive hypervolemia during the interdialytic period.
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Absolute value of access flow (QA) and change in flow (deltaQA) over time are major determinants of access patency. However, QA may change in response to variation in systemic hemodynamics among dialysis sessions. We examined the effect of mean arterial pressure (MAP), cardiac output (CO), and segmental resistances (R) on QA. ⋯ The pressure in the venous system draining the access affected access flow in AVF but not grafts. We conclude that the hemodynamics of grafts and AVF differ. Cardiac output, MAP, and the arterial segment resistance influence QA in both access types and need to be considered when evaluating QA as part of the trend analysis for detecting access dysfunction.