title: Can changes in arterial pressure be used to detect changes in cardiac output during volume expansion in the perioperative period?
abstract: BACKGROUND
  Cardiac output (CO) is rarely monitored during surgery, and arterial pressure remains the only hemodynamic parameter for assessing the effects of volume expansion (VE). However, whether VE-induced changes in arterial pressure accurately reflect changes in CO has not been demonstrated. The authors studied the ability of VE-induced changes in arterial pressure and in pulse pressure variation to detect changes in CO induced by VE in the perioperative period.
  
  
  METHODS
  The authors studied 402 patients in four centers. Hemodynamic variables were recorded before and after VE. Response to VE was defined as more than 15% increase in CO. The ability of VE-induced changes in arterial pressure to detect changes in CO was assessed using a gray zone approach.
  
  
  RESULTS
  VE increased CO of more than 15% in 205 patients (51%). Areas under the receiver operating characteristic curves for VE-induced changes in systolic, diastolic, means, and pulse pressure ranged between 0.64 and 0.70, and sensitivity and specificity ranged between 52 and 79%. For these four arterial pressure-derived parameters, large gray zones were found, and more than 60% of the patients lay within this inconclusive zone. A VE-induced decrease in pulse pressure variation of 3% or more allowed detecting a fluid-induced increase in CO of more than 15% with a sensitivity of 90% and a specificity of 77% and a gray zone between 2.2 and 4.7% decrease in pulse pressure variation including 14% of the patients.
  
  
  CONCLUSIONS
  Only changes in pulse pressure variation accurately detect VE-induced changes in CO and have a potential clinical applicability.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Centre Hospitalier Universitaire Pitié-Salpêtrière, Paris, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Le Manach
authors.forename: Christoph K
authors.initials: CK
authors.lastname: Hofer
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Lehot
authors.forename: Benoît
authors.initials: B
authors.lastname: Vallet
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Goarin
authors.forename: Benoît
authors.initials: B
authors.lastname: Tavernier
authors.forename: Maxime
authors.initials: M
authors.lastname: Cannesson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D062186:Arterial Pressure / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology*; D001811:Blood Volume Determination / Q000379:methods; D002302:Cardiac Output / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D059035:Perioperative Period / Q000379:methods*; D011446:Prospective Studies; D012189:Retrospective Studies