title: Influence of Diaphragmatic Motion on Inferior Vena Cava Diameter Respiratory Variations in Healthy Volunteers.
abstract: The collapsibility index of inferior vena cava (cIVC) is widely used to decide fluid infusion in spontaneously breathing intensive care unit patients. The authors hypothesized that high inspiratory efforts may induce false-positive high cIVC values. This study aims at determining a value of diaphragmatic motion recorded by echography that could predict a high cIVC (more than or equal to 40%) in healthy volunteers.
  
  
  
  The cIVC and diaphragmatic motions were recorded for three levels of inspiratory efforts. Right and left diaphragmatic motions were defined as the maximal diaphragmatic excursions. Receiver operating characteristic curves evaluated the performance of right diaphragmatic motion to predict a cIVC more than or equal to 40% defining the best cutoff value.
  
  
  
  Among 52 included volunteers, interobserver reproducibility showed a generalized concordance correlation coefficient (ρc) above 0.9 for all echographic parameters. Right diaphragmatic motion correlated with cIVC (r = 0.64, P < 0.0001). Univariate analyses did not show association between cIVC and age, sex, weight, height, or body mass index. The area under the receiver operating characteristic curves for cIVC more than or equal to 40% was 0.87 (95% CI, 0.81 to 0.93). The best diaphragmatic motion cutoff was 28 mm (Youden Index, 0.65) with sensitivity of 89% and specificity of 77%. The gray zone area was 25 to 43 mm.
  
  
  
  Inferior vena cava collapsibility is affected by diaphragmatic motion. During low inspiratory effort, diaphragmatic motion was less than 25 mm and predicted a cIVC less than 40%. During maximal inspiratory effort, diaphragmatic motion was more than 43 mm and predicted a cIVC more than 40%. When diaphragmatic motion ranged from 25 to 43 mm, no conclusion on cIVC value could be done.
authors.affiliation: From the Departments of Anesthesiology (L.G., C.R., L. Zoric, X.B., J.-Y.L., L.M.), Critical Care (L.G., C.R., L. Zoric, X.B., J.-Y.L., L.M.), and Biostatistics and Clinical Epidemiology (S.B., S.A.), CHU Caremeau, Nîmes, France; EA2992 Laboratory of Dysfunction of Vascular Interfaces, Nîmes Medicine University, Nîmes, France (C.R., J.-Y.L., L.M.); Department of Anesthesiology and Critical Care, CHU Pitié-Salpêtrière, Paris, France (M.R.); Department of Anesthesiology and Critical Care, CHU Nord, Marseille, France (L. Zieleskiewicz, M.L.); and Department of Anesthesiology and Critical Care, CHU Saint Roch, Nice, France (H.Q.).
authors.forename: Lucile
authors.initials: L
authors.lastname: Gignon
authors.forename: Claire
authors.initials: C
authors.lastname: Roger
authors.forename: Sophie
authors.initials: S
authors.lastname: Bastide
authors.forename: Sandrine
authors.initials: S
authors.lastname: Alonso
authors.forename: Laurent
authors.initials: L
authors.lastname: Zieleskiewicz
authors.forename: Hervé
authors.initials: H
authors.lastname: Quintard
authors.forename: Lana
authors.initials: L
authors.lastname: Zoric
authors.forename: Xavier
authors.initials: X
authors.lastname: Bobbia
authors.forename: Mathieu
authors.initials: M
authors.lastname: Raux
authors.forename: Marc
authors.initials: M
authors.lastname: Leone
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Lefrant
authors.forename: Laurent
authors.initials: L
authors.lastname: Muller
mesh_terms: D000328:Adult; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D012119:Respiration; D014463:Ultrasonography; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging* / Q000502:physiology*