title: Brachial artery peak velocity variation to predict fluid responsiveness in mechanically ventilated patients.
abstract: BACKGROUND
  Although several parameters have been proposed to predict the hemodynamic response to fluid expansion in critically ill patients, most of them are invasive or require the use of special monitoring devices. The aim of this study is to determine whether noninvasive evaluation of respiratory variation of brachial artery peak velocity flow measured using Doppler ultrasound could predict fluid responsiveness in mechanically ventilated patients.
  
  
  METHODS
  We conducted a prospective clinical research in a 17-bed multidisciplinary ICU and included 38 mechanically ventilated patients for whom fluid administration was planned due to the presence of acute circulatory failure. Volume expansion (VE) was performed with 500 mL of a synthetic colloid. Patients were classified as responders if stroke volume index (SVi) increased >or= 15% after VE. The respiratory variation in Vpeakbrach (DeltaVpeakbrach) was calculated as the difference between maximum and minimum values of Vpeakbrach over a single respiratory cycle, divided by the mean of the two values and expressed as a percentage. Radial arterial pressure variation (DeltaPPrad) and stroke volume variation measured using the FloTrac/Vigileo system (DeltaSVVigileo), were also calculated.
  
  
  RESULTS
  VE increased SVi by >or= 15% in 19 patients (responders). At baseline, DeltaVpeakbrach, DeltaPPrad and DeltaSVVigileo were significantly higher in responder than nonresponder patients [14 vs 8%; 18 vs. 5%; 13 vs 8%; P < 0.0001, respectively). A DeltaVpeakbrach value >10% predicted fluid responsiveness with a sensitivity of 74% and a specificity of 95%. A DeltaPPrad value >10% and a DeltaSVVigileo >11% predicted volume responsiveness with a sensitivity of 95% and 79%, and a specificity of 95% and 89%, respectively.
  
  
  CONCLUSIONS
  Respiratory variations in brachial artery peak velocity could be a feasible tool for the noninvasive assessment of fluid responsiveness in patients with mechanical ventilatory support and acute circulatory failure.
  
  
  BACKGROUND
  ClinicalTrials.gov ID: NCT00890071.
authors.affiliation: Servicio de Cuidados Críticos y Urgencias, Unidad de Investigación Experimental, Hospital del SAS Jerez, Jerez de la Frontera, Spain. ignaciomonge@gmail.com
authors.forename: Manuel Ignacio
authors.initials: MI
authors.lastname: Monge García
authors.forename: Anselmo
authors.initials: A
authors.lastname: Gil Cano
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Díaz Monrové
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology*; D001916:Brachial Artery / Q000000981:diagnostic imaging*; D015150:Echocardiography, Doppler; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012121:Respiration, Artificial; D013030:Spain; D013318:Stroke Volume / Q000502:physiology