title: Gastric intramucosal acidosis in mechanically ventilated patients: role of mucosal blood flow.
abstract: OBJECTIVE
  To investigate whether gastric intramucosal acidosis is associated with a decreased gastric mucosal blood flow in mechanically ventilated patients.
  
  
  METHODS
  Prospective, clinical investigation.
  
  
  METHODS
  University hospital intensive care unit.
  
  
  METHODS
  Seventeen mechanically ventilated patients with stable hemodynamic status.
  
  
  METHODS
  Gastric tonometry and endoscopic assessment of mucosal blood flow.
  
  
  RESULTS
  Six patients had gastric intramucosal acidosis (intramucosal pH [pHi] of 7.24 +/- 0.06), whereas the remaining 11 patients had pHi values within the normal range (7.44 +/- 0.01). No differences were found between intramucosal acidotic and nonacidotic patients with respect to their general and hemodynamic characteristics. Patients with intramucosal acidosis had a lower gastric mucosal blood flow, as assessed by laser-Doppler flowmetry, than nonacidotic patients (1.4 +/- 0.1 vs. 2.1 +/- 0.2 volts, respectively; p < .05). Reflectance spectrophotometry disclosed that patients with low gastric pHi had also a significantly (p < .05) lower hemoglobin content index (61 +/- 4 arbitrary units) than patients with normal pHi (81 +/- 3 arbitrary units), whereas oxygen saturation index was similar for both groups.
  
  
  CONCLUSIONS
  Our results support the hypothesis that gastric mucosal hypoperfusion underlies the development of intramucosal acidosis in mechanically ventilated patients.
authors.affiliation: Serveis de Gastroenterologia, Departament de Medicina, Hospital Clínic, Universitat de Barcelona, Spain.
authors.forename: J I
authors.initials: JI
authors.lastname: Elizalde
authors.forename: C
authors.initials: C
authors.lastname: Hernández
authors.forename: J
authors.initials: J
authors.lastname: Llach
authors.forename: C
authors.initials: C
authors.lastname: Montón
authors.forename: J M
authors.initials: JM
authors.lastname: Bordas
authors.forename: J M
authors.initials: JM
authors.lastname: Piqué
authors.forename: A
authors.initials: A
authors.lastname: Torres
mesh_terms: D018806:APACHE; D000138:Acidosis / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D000368:Aged; D005260:Female; D005753:Gastric Mucosa / Q000098:blood supply* / Q000737:chemistry; D006439:Hemodynamics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007362:Intensive Care Units; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012121:Respiration, Artificial; D013053:Spectrophotometry; D013152:Splanchnic Circulation