title: Pulmonary and Systemic Vascular Resistances After Cardiopulmonary Bypass: Role of Hemolysis.
abstract: OBJECTIVE
  Prolonged cardiopulmonary bypass (CPB) is associated with hemolysis, resulting in increased plasma oxyhemoglobin and vascular nitric oxide depletion. The authors hypothesized that hemolysis associated with CPB would reduce nitric oxide bioavailability, resulting in high pulmonary and systemic vascular resistances that after CPB would normalize gradually over time, due to clearance of plasma oxyhemoglobin. The authors also investigated whether prolonged CPB (≥140 min) produced increased levels of hemolysis and greater pulmonary and systemic vasoconstriction.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Single-center university hospital.
  
  
  METHODS
  The study comprised 50 patients undergoing elective cardiac surgery requiring CPB.
  
  
  METHODS
  Plasma hemoglobin and plasma nitric oxide consumption were measured before surgery and after CPB. Pulmonary and systemic hemodynamics were measured after CPB. The effects of short (<140 min) and prolonged (≥140 min) CPB on these parameters were considered.
  
  
  RESULTS
  Pulmonary and systemic vascular resistances and plasma hemoglobin and nitric oxide consumption were highest at 15 minutes after CPB and then decreased over time. Pulmonary and systemic vascular resistances and plasma hemoglobin and plasma nitric oxide consumption were higher in patients requiring prolonged CPB. The reduction in plasma nitric oxide consumption from 15 minutes to 4 hours after CPB was correlated independently with the reductions in pulmonary and systemic vascular resistances.
  
  
  CONCLUSIONS
  Prolonged CPB was associated with increased plasma hemoglobin and plasma nitric oxide consumption and pulmonary and systemic vascular resistances. The reduction in plasma nitric oxide consumption at 4 hours after CPB was an independent predictor of the concomitant reductions in pulmonary and systemic vascular resistances.
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Emanuele
authors: E
authors: Rezoagli
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Fumito
authors: F
authors: Ichinose
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Sabrina
authors: S
authors: Strelow
authors: Division of Cardiac Surgery of the Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Nathalie
authors: N
authors: Roy
authors: Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Kenneth
authors: K
authors: Shelton
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Rui
authors: R
authors: Matsumine
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Liu
authors: L
authors: Chen
authors: Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Edward A
authors: EA
authors: Bittner
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA; Division of Rheumatology, Allergy and Immunology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Donald B
authors: DB
authors: Bloch
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors: Warren M
authors: WM
authors: Zapol
authors: Anesthesia Center for Critical Care Research, Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA. Electronic address: lberra@mgh.harvard.edu.
authors: Lorenzo
authors: L
authors: Berra
mesh_terms: D000368:Aged; D002315:Cardiopulmonary Bypass / Q000009:adverse effects* / Q000639:trends; D015331:Cohort Studies; D005260:Female; D006461:Hemolysis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D011446:Prospective Studies; D014655:Vascular Resistance / Q000502:physiology*
keywords: cardiopulmonary bypass; hemolysis; nitric oxide; plasma hemoglobin; pulmonary vascular resistance; systemic vascular resistance