title: Intraoperative coagulation was more interfered by HES 200/0.5 than normal saline in off-pump coronary artery bypass surgery.
abstract: OBJECTIVE
  Rapid fluid administration is often necessary for anesthesiologists to maintain intravascular volume in off-pump coronary artery bypass (OPCAB) with acceptable hematocrits. Postoperative hypocoagulation involving postoperative bleeding and hypercoagulation involving graft patency were focused in previous studies but bleeding and blood transfusion are often peaked during vascular anastomoses during OPCAB. This study is designed to investigate the sequential effects of intraoperative coagulation with normal saline and hydroxyethyl starch (HES) solution by thromboelastography (TEG) and standard coagulation tests (SCT).
  
  
  METHODS
  Twenty adult patients scheduled for OPCAB were enrolled in this study. After anesthetic induction, one group received HES 200/0.5 infusion up to 20 mL/kg and the other received 0.9% normal saline (NS) to maintain central venous pressure (CVP) and pulmonary artery occlusion pressures (PAOP). SCT and TEG were measured at T0 (baseline), T1 (after heparin 150 IU/kg, before vascular anastomoses), T2 (after protamine reversal), and T3 (24 hrs after the surgery) to compare the coagulation status.
  
  
  RESULTS
  Baseline data were comparable in both groups. The number of patient who need blood components is higher in HES group. Dilutional hypocoagulation was shown by a significant prolongation of R time at T1 and T2 but also returned comparable at T3 in both groups. K, a-angle, CI and G remained unchanged in NS group but significantly affected in HES group. A statistically significant interaction between groups and treatments on maximal amplitude (MA) (P<0.01) with more blood loss in HES group 24 hours postoperatively (P=0.05). International Normalized Ratio (INR) increased significantly at T2 and T3 in both groups.
  
  
  CONCLUSIONS
  A rapid infusion of either normal saline or HES solution to maintain intraoperative intravascular volume induce a significant diluted hypocoagulation during OPCAB. The use of HES solution has a prolonged dilutional hypocoagulation and a significant decrease of MA by specific platelet inhibition effects and more transfusion of blood components. All the above changes were not shown in standard coagulation tests.
authors.affiliation: Department of Anesthesiology, National Taiwan University Hospital, National Taiwan University, No. 7 Chung-Shan South Road, Taipei, Taiwan.
authors.forename: T S
authors.initials: TS
authors.lastname: Yen
authors.forename: K C
authors.initials: KC
authors.lastname: Chan
authors.forename: Y J
authors.initials: YJ
authors.lastname: Cheng
mesh_terms: D000704:Analysis of Variance; D001777:Blood Coagulation / Q000187:drug effects*; D047549:Coronary Artery Bypass, Off-Pump; D005260:Female; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage*; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D012965:Sodium Chloride / Q000008:administration & dosage*
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D012965:Sodium Chloride