title: Changes in circulating blood volume after cardiac surgery measured by a novel method using hydroxyethyl starch.
abstract: OBJECTIVE
  To determine the incidence and extent of postoperative blood volume (BV) changes in patients after elective cardiac surgery using a new method based on dilution of hydroxyethyl-starch.
  
  
  METHODS
  Prospective, clinical, and laboratory investigation.
  
  
  METHODS
  University hospital intensive care unit.
  
  
  METHODS
  A total of thirty-five patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB).
  
  
  METHODS
  Perioperative measurements of circulating BV, systemic hemodynamics, lactate, and collection of clinical data.
  
  
  RESULTS
  Measurements were made before and 1 to 72 hrs after CPB. The majority of patients undergoing cardiac surgery showed postoperative BV deficits compared with preoperative BV despite marked positive fluid balances after CPB. At 1 hr and 5 hrs after CPB, 18% and 33% of the patients, respectively, had BV deficits in the range of 0.5 L and 1.5 L, and in 3% to 10% of the cases, postoperative BV deficits exceeded 1.5 L. Concomitantly, at 5 hrs after CPB, mean arterial pressure was maximally reduced, and heart rate and lactate levels were maximally elevated. Thereafter, BV began to normalize, and at 24 hrs after CPB, pre- and postoperative mean BV were no longer significantly different. At 48 hrs and 72 hrs, even a BV surplus of more than 1 L could be observed in 6% and 14% of the patients, respectively.
  
  
  CONCLUSIONS
  During the first hours after CPB, a high percentage of patients had significantly reduced BV and, concomitantly, showed cardiovascular dysfunction and hyperlactemia. Because hypovolemia is associated with increases of perioperative morbidity and mortality, rapid determination of BV is warranted to guide fluid therapy and optimize treatment in patients undergoing cardiac surgery.
authors.affiliation: Department of Anesthesiology, University of Erlangen-Nürnberg, Germany. klaus.tschaikowsky@rzmail.uni-erlangen.de
authors.forename: K
authors.initials: K
authors.lastname: Tschaikowsky
authors.forename: U
authors.initials: U
authors.lastname: Neddermeyer
authors.forename: E
authors.initials: E
authors.lastname: Pscheidl
authors.forename: J
authors.initials: J
authors.lastname: von der Emde
mesh_terms: D000328:Adult; D000368:Aged; D001810:Blood Volume; D002496:Central Venous Pressure; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives; D020896:Hypovolemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D007201:Indicator Dilution Techniques / Q000592:standards*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D010952:Plasma Substitutes; D011182:Postoperative Care / Q000379:methods; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D006454:Hemoglobins; D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes