title: Respiratory variations of inferior vena cava diameter to predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure: need for a cautious use.
abstract: BACKGROUND
  To investigate whether respiratory variation of inferior vena cava diameter (cIVC) predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure (ACF).
  
  
  METHODS
  Forty patients with ACF and spontaneous breathing were included. Response to fluid challenge was defined as a 15% increase of subaortic velocity time index (VTI) measured by transthoracic echocardiography. Inferior vena cava diameters were recorded by a subcostal view using M Mode. The cIVC was calculated as follows: (Dmax - Dmin/Dmax) × 100 and then receiver operating characteristic (ROC) curves were generated for cIVC, baseline VTI, E wave velocity, E/A and E/Ea ratios.
  
  
  RESULTS
  Among 40 included patients, 20 (50%) were responders (R). The causes of ACF were sepsis (n = 24), haemorrhage (n = 11), and dehydration (n = 5). The area under the ROC curve for cIVC was 0.77 (95% CI: 0.60-0.88). The best cutoff value was 40% (Se = 70%, Sp = 80%). The AUC of the ROC curves for baseline E wave velocity, VTI, E/A ratio, E/Ea ratio were 0.83 (95% CI: 0.68-0.93), 0.78 (95% CI: 0.61-0.88), 0.76 (95% CI: 0.59-0.89), 0.58 (95% CI: 0.41-0.75), respectively. The differences between AUC the ROC curves for cIVC and baseline E wave velocity, baseline VTI, baseline E/A ratio, and baseline E/Ea ratio were not statistically different (p = 0.46, p = 0.99, p = 1.00, p = 0.26, respectively).
  
  
  CONCLUSIONS
  In spontaneously breathing patients with ACF, high cIVC values (>40%) are usually associated with fluid responsiveness while low values (< 40%) do not exclude fluid responsiveness.
authors.forename: Laurent
authors.initials: L
authors.lastname: Muller
authors.forename: Xavier
authors.initials: X
authors.lastname: Bobbia
authors.forename: Mehdi
authors.initials: M
authors.lastname: Toumi
authors.forename: Guillaume
authors.initials: G
authors.lastname: Louart
authors.forename: Nicolas
authors.initials: N
authors.lastname: Molinari
authors.forename: Benoit
authors.initials: B
authors.lastname: Ragonnet
authors.forename: Hervé
authors.initials: H
authors.lastname: Quintard
authors.forename: Marc
authors.initials: M
authors.lastname: Leone
authors.forename: Lana
authors.initials: L
authors.lastname: Zoric
authors.forename: Jean Yves
authors.initials: JY
authors.lastname: Lefrant
mesh_terms: D000208:Acute Disease; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology*; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015656:Respiratory Mechanics / Q000502:physiology*; D012769:Shock / Q000503:physiopathology* / Q000628:therapy; D013318:Stroke Volume / Q000502:physiology*; D014682:Vena Cava, Inferior / Q000502:physiology*