title: Effects of positive end-expiratory pressure ventilation on splanchnic oxygenation in humans.
abstract: OBJECTIVE
  To examine the influence of positive end-expiratory pressure (PEEP) ventilation on splanchnic oxygenation and lactate production in humans without pulmonary disorders.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Single-institutional surgical intensive care unit in a university hospital.
  
  
  METHODS
  Twenty patients who underwent major abdominal surgery.
  
  
  METHODS
  Radial artery, pulmonary artery, and right hepatic vein catheters. Blood samples were collected to determine lactate concentrations and oxygen saturations.
  
  
  RESULTS
  Six hours postoperatively PEEP levels (5, 10, and 15 cmH2O) were applied in a randomized order, and the following parameters were determined before and at the end of each PEEP level: cardiac output (CO); mean arterial pressure (MAP); arterial (SaO2), mixed venous (SvO2) and hepatic venous oxygen saturation (ShvO2); systemic (C[a-v]O2) and splanchnic (C[a-hv]O2) arterial venous oxygen content difference; and arterial, mixed venous, and hepatic venous lactate concentration. CO and MAP were reduced at PEEP 10 and 15 cmH2O, accompanied by a decrease in SvO2 but unchanged SaO2. A decrease in ShvO2 was seen at PEEP 15 cmH2O. C(a-v)O2 and C(a-hv)O2 were increased at PEEP 15 cmH2O. However, at PEEP 15 cmH2O, the percent increment in C(a-hv)O2 was greater than the increment in C(a-v)O2. Lactate concentrations remained unchanged.
  
  
  CONCLUSIONS
  Ventilation with PEEP causes reductions in CO and MAP, resulting in a comparable impairment of systemic and splanchnic oxygen. The absence of changes in lactate concentrations indicates that a critical reduction in systemic and splanchnic oxygenation is unlikely during ventilation with low or high PEEP levels.
authors.affiliation: Klinik und Poliklinik für Anaesthesiologie, Westfälische Wilhelms-Universität, Münster, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Berendes
authors.forename: G
authors.initials: G
authors.lastname: Lippert
authors.forename: H M
authors.initials: HM
authors.lastname: Loick
authors.forename: T
authors.initials: T
authors.lastname: Brüssel
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006439:Hemodynamics; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008102:Liver Circulation; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D013152:Splanchnic Circulation
chemical_list: D019344:Lactic Acid; D010100:Oxygen