title: Respiratory Collapse of the Inferior Vena Cava Reflects Volume Shift and Subsequent Fluid Refill in Acute Heart Failure Syndrome.
abstract: BACKGROUND
  Fluid redistribution rather than fluid accumulation plays an important role in the development of acute heart failure (HF) syndrome. Patients with fluid redistribution develop acute HF without prominent volume overload. We investigated volume status by measuring the diameter of the inferior vena cava (IVC) and examining variations in hemoglobin and hematocrit.
  
  
  RESULTS
  Seventy-four consecutive patients admitted for acute HF syndrome were analyzed. Blood tests and measurement of IVC diameter after stabilization of respiratory distress were performed on admission and were repeated after 24 h. IVC collapsibility index (IVC-CI) was calculated as (maximum IVC-minimum IVC)/maximum IVC. According to the initial IVC-CI, the patients were divided into the collapse group (IVC-CI ≥0.5: n=34) and the non-collapse group (IVC-CI <0.5: n=40). Initial blood pressure was higher in the collapse group (P<0.001). Although 24-h urine volume did not differ between the groups, hemoglobin (P<0.001) and hematocrit (P<0.001) decreased significantly in the collapse group but not in the non-collapse group after 24 h. Furthermore, IVC-CI significantly decreased in the collapse group after 24 h (P=0.003).
  
  
  CONCLUSIONS
  In acute HF syndrome, IVC-CI ≥0.5 on admission suggests a volume shift from the central vein into the pulmonary vasculature. Fluid refill occurs within 24 h after admission. This observation could be helpful in selecting strategies for diuretic use. (Circ J 2016; 80: 1171-1177).
authors.affiliation: Department of Cardiology, Naha City Hospital.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Asahi
authors.forename: Marohito
authors.initials: M
authors.lastname: Nakata
authors.forename: Namio
authors.initials: N
authors.lastname: Higa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Manita
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tabata
authors.forename: Michio
authors.initials: M
authors.lastname: Shimabukuro
mesh_terms: D000208:Acute Disease; D001794:Blood Pressure; D015331:Cohort Studies; D006333:Heart Failure / Q000503:physiopathology*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D057446:Hydrodynamics; D014682:Vena Cava, Inferior / Q000503:physiopathology*
chemical_list: D006454:Hemoglobins