title: Is kidney function altered by the duration of cardiopulmonary bypass?
abstract: BACKGROUND
  Cardiopulmonary bypass (CPB) is considered responsible for kidney damage. By using sensitive markers of kidney damage we assessed whether the length of CPB influences kidney function.
  
  
  METHODS
  In a prospective study, 50 consecutive cardiac operation patients with CPB times of less than 70 minutes were compared with 50 consecutive patients showing CPB times of more than 90 minutes. Aside from creatinine clearance and fractional excretion of sodium, urine concentrations of N-acetyl-beta-D-glucosaminidase, alpha1-microglobulin, glutathione transferase-pi, and glutathione transferase-alpha were measured after induction of anesthesia at the end of the operation, and on the first and second postoperative days in the intensive care unit.
  
  
  RESULTS
  CPB times were 58 +/- 12 minutes and 116 +/- 18 minutes, respectively. Hemodynamics, volume replacement, and use of catecholamines during cardiopulmonary bypass (CPB) were without significant differences between groups. Concentrations of all kidney-specific proteins increased significantly after CPB, showing the highest significant increases in the CPB more than 90 minutes group (eg, glutathione transferase-alpha CPB > 90 minutes from 3.0 +/- 1.0 to 12.9 +/- 2.9 microg/L; glutathione transferase-alpha CPB < 70 minutes from 2.4 +/- 0.5 to 5.5 +/- 1.2 microg/L). By the second postoperative day, urine concentrations of kidney-specific proteins had returned to almost baseline in the CPB less than 70 minutes patients, but remained slightly elevated in the other group.
  
  
  CONCLUSIONS
  Patients with CPB times more than 90 minutes showed more pronounced kidney damage than patients with CPB times less than 70 minutes as assessed by sensitive kidney-specific proteins. Whether patients with preexisting renal dysfunction undergoing prolonged CPB times would profit from renal protection strategies needs to be elucidated.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Klinikum der Stadt Ludwigshafen, Ludwigshafen, Germany. boldtj@gmx.net
authors.forename: Joachim
authors.initials: J
authors.lastname: Boldt
authors.forename: Torsten
authors.initials: T
authors.lastname: Brenner
authors.forename: Andreas
authors.initials: A
authors.lastname: Lehmann
authors.forename: Stephan W
authors.initials: SW
authors.lastname: Suttner
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kumle
authors.forename: Frank
authors.initials: F
authors.lastname: Isgro
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology*; D000368:Aged; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology*; D011446:Prospective Studies; D011507:Proteinuria / Q000209:etiology; D012307:Risk Factors