title: Dehydration, hemodynamics and fluid volume optimization after induction of general anesthesia.
abstract: OBJECTIVE
  Fluid volume optimization guided by stroke volume measurements reduces complications of colorectal and high-risk surgeries. We studied whether dehydration or a strong hemodynamic response to general anesthesia increases the probability of fluid responsiveness before surgery begins.
  
  
  METHODS
  Cardiac output, stroke volume, central venous pressure and arterial pressures were measured in 111 patients before general anesthesia (baseline), after induction and stepwise after three bolus infusions of 3 ml/kg of 6% hydroxyethyl starch 130/0.4 (n=86) or Ringer's lactate (n=25). A subgroup of 30 patients who received starch were preloaded with 500 ml of Ringer's lactate. Blood volume changes were estimated from the hemoglobin concentration and dehydration was estimated from evidence of renal water conservation in urine samples.
  
  
  RESULTS
  Induction of anesthesia decreased the stroke volume to 62% of baseline (mean); administration of fluids restored this value to 84% (starch) and 68% (Ringer's). The optimized stroke volume index was clustered around 35-40 ml/m2/beat. Additional fluid boluses increased the stroke volume by ≥10% (a sign of fluid responsiveness) in patients with dehydration, as suggested by a low cardiac index and central venous pressure at baseline and by high urinary osmolality, creatinine concentration and specific gravity. Preloading and the hemodynamic response to induction did not correlate with fluid responsiveness. The blood volume expanded 2.3 (starch) and 1.8 (Ringer's) times over the infused volume.
  
  
  CONCLUSIONS
  Fluid volume optimization did not induce a hyperkinetic state but ameliorated the decrease in stroke volume caused by anesthesia. Dehydration, but not the hemodynamic response to the induction, was correlated with fluid responsiveness.
authors: Department of Anaesthesia, Shaoxing People's Hospital, People's Republic of China.
authors: Yuhong
authors: Y
authors: Li
authors: Department of Anaesthesia, Shaoxing People's Hospital, People's Republic of China.
authors: Rui
authors: R
authors: He
authors: Department of Colorectal Surgery, Shaoxing People's Hospital, People's Republic of China.
authors: Xiaojiang
authors: X
authors: Ying
authors: Research Unit, Södertälje Hospital, Södertälje, Sweden.
authors: Robert G
authors: RG
authors: Hahn
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000768:Anesthesia, General / Q000379:methods*; D001810:Blood Volume / Q000502:physiology; D003681:Dehydration / Q000503:physiopathology*; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000627:therapeutic use; D007552:Isotonic Solutions / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D010952:Plasma Substitutes / Q000627:therapeutic use; D012372:ROC Curve; D000077325:Ringer's Lactate; D018709:Statistics, Nonparametric; D013318:Stroke Volume / Q000502:physiology*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D007552:Isotonic Solutions; D010952:Plasma Substitutes; D000077325:Ringer's Lactate
references: Br J Anaesth. 2005 Nov;95(5):634-42
references: 16155038
references: Int J Sport Nutr Exerc Metab. 2005 Jun;15(3):236-51
references: 16131695
references: Crit Care. 2009;13(2):R40
references: 19302713
references: Crit Care. 2009;13(6):R195
references: 19968880
references: Acta Anaesthesiol Scand. 2010 Apr;54(4):464-9
references: 20002360
references: Anesthesiology. 2010 Aug;113(2):470-81
references: 20613481
references: Anesth Analg. 2011 Jun;112(6):1384-91
references: 21156979
references: Br J Anaesth. 2013 Apr;110(4):545-53
references: 23274782
references: Int J Sport Nutr Exerc Metab. 2013 Aug;23(4):303-11
references: 23994895
references: J Clin Anesth. 2013 Sep;25(6):466-74
references: 23965199
references: Eur J Anaesthesiol. 2014 Feb;31(2):85-90
references: 24145802
references: Br J Anaesth. 2014 Feb;112(2):281-9
references: 24056586
references: Crit Care. 2013;17(3):R104
references: 23718743
references: Crit Care. 2013;17(2):209
references: 23672779
references: Med Sci Sports Exerc. 2001 May;33(5):747-53
references: 11323543
references: Anesth Analg. 2004 Dec;99(6):1854-60, table of contents
references: 15562086
references: Anesthesiology. 2005 Sep;103(3):460-9
references: 16129968
references: Anesth Analg. 2009 Jan;108(1):128-33
references: 19095840