title: Arm occlusion pressure is a useful predictor of an increase in cardiac output after fluid loading following cardiac surgery.
abstract: OBJECTIVE
  In pharmacological research, arm occlusion pressure is used to study haemodynamic effects of drugs. However, arm occlusion pressure might be an indicator of static filling pressure of the arm. We hypothesised that arm occlusion pressure can be used to predict fluid loading responsiveness.
  
  
  METHODS
  Twenty-four patients who underwent cardiac surgery were studied during their first 2 h in the ICU. The lungs were ventilated mechanically and left ventricular function was supported as necessary. Arm occlusion pressure was defined as the radial artery pressure after occluding arterial flow for 35 s by a blood pressure cuff inflated to 50 mmHg above SBP. The cuff was positioned around the arm in which a radial artery catheter had been inserted. Measurements were performed before (baseline) and after fluid loading (500 ml hydroxyethyl starch 6%). Patients whose cardiac output increased by at least 10% were defined as responders.
  
  
  RESULTS
  In responders (n = 17), arm occlusion pressure, mean arterial pressure and central venous pressure increased and stroke volume variation and pulse pressure variation decreased. In non-responders (n = 7), arm occlusion pressure and central venous pressure increased, and pulse pressure variation decreased. Mean arterial pressure, stroke volume variation and heart rate did not change significantly. The area under the curve to predict fluid loading responsiveness for arm occlusion pressure was 0.786 (95% confidence interval 0.567-1.000), at a cut-off of 21.9 mmHg, with sensitivity of 71% and specificity of 88% in predicting fluid loading responsiveness. Prediction of responders with baseline arm occlusion pressure was as good as baseline stroke volume variation and pulse pressure variation.
  
  
  CONCLUSIONS
  Arm occlusion pressure was a good predictor of fluid loading responsiveness in our group of cardiac surgery patients and offers clinical advantages over stroke volume variation and pulse pressure variation.
authors.affiliation: Department of Anaesthesiology, Leiden University Medical Centre, P-05, Albinusdreef 2, PO Box 9600, 2500 RC Leiden, The Netherlands. b.f.geerts@lumc.nl
authors.forename: Bart F
authors.initials: BF
authors.lastname: Geerts
authors.forename: Jacinta
authors.initials: J
authors.lastname: Maas
authors.forename: Rob B P
authors.initials: RB
authors.lastname: de Wilde
authors.forename: Leon P H J
authors.initials: LP
authors.lastname: Aarts
authors.forename: Jos R C
authors.initials: JR
authors.lastname: Jansen
mesh_terms: D000368:Aged; D001132:Arm / Q000098:blood supply*; D001794:Blood Pressure / Q000187:drug effects*; D001795:Blood Pressure Determination / Q000379:methods; D002302:Cardiac Output / Q000187:drug effects*; D006348:Cardiac Surgical Procedures; D002496:Central Venous Pressure / Q000187:drug effects; D017558:Elective Surgical Procedures; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage*; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010952:Plasma Substitutes / Q000008:administration & dosage*; D019095:Point-of-Care Systems; D011237:Predictive Value of Tests; D017534:Radial Artery / Q000187:drug effects*; D012121:Respiration, Artificial; D013997:Time Factors
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes