title: Moderate-degree acidosis is an independent determinant of postoperative bleeding in cardiac surgery.
abstract: BACKGROUND
  Acidosis is a well-known factor leading to coagulopathy. It has been widely explored as a risk factor for severe bleeding in trauma patients. However, no information with respect to acidosis as a determinant of postoperative bleeding in cardiac surgery patients exists. The aim of this study was to investigate the role of acidosis and hyperlactatemia (HL) in determining postoperative bleeding and need for surgical revision in cardiac surgery patients.
  
  
  METHODS
  We carried out a retrospective analysis on 4521 patients receiving cardiac operations in two institutions. For each patient the preoperative data and operative profile was available. Arterial blood gas analysis data at the arrival in the intensive care unit were analyzed to investigate the association between acidosis (pH<7.35), HL (>4.0 mMol/L) and postoperative bleeding and surgical revision rate.
  
  
  RESULTS
  After correction for the potential confounders, both acidosis (P=0.001) and HL (P=0.001) were significantly associated with the amount of postoperative bleeding. HL was an independent risk factor for postoperative bleeding even in absence of acidosis. Overall, surgical revision rate was 5.6% in patients with HL and no acidosis; 7.7% in patients with acidosis and HL, and 7.2% in patients with acidosis and no HL. All these values are significantly (P=0.001) higher than the ones in patients without acidosis/HL (2%).
  
  
  CONCLUSIONS
  Even a moderate degree of postoperative acidosis is associated with a greater postoperative bleeding and surgical revision rate in cardiac surgery patients. Correction of acidosis with bicarbonate does not lead to an improvement of the postoperative bleeding asset.
authors.affiliation: Department of Cardiothoracic and Vascular Anesthesia and ICU, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy - cardioanestesia@virgilio.it.
authors.forename: M
authors.initials: M
authors.lastname: Ranucci
authors.forename: E
authors.initials: E
authors.lastname: Baryshnikova
authors.forename: F
authors.initials: F
authors.lastname: Simeone
authors.forename: M
authors.initials: M
authors.lastname: Ranucci
authors.forename: S
authors.initials: S
authors.lastname: Scolletta
mesh_terms: D000138:Acidosis / Q000150:complications* / Q000188:drug therapy; D000368:Aged; D001639:Bicarbonates / Q000627:therapeutic use; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D019106:Postoperative Hemorrhage / Q000209:etiology*; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D001639:Bicarbonates; D019344:Lactic Acid