title: Gastric mucosal pH and blood flow during weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease.
abstract: To determine if gastric intramucosal pH changes during weaning from mechanical ventilation are related to gastric mucosal blood flow modifications, we studied 16 ventilator-supported patients with chronic obstructive pulmonary disease (COPD) who tolerated a 2-h trial of spontaneous breathing with pressure support ventilation and were successfully extubated and 11 patients with COPD who failed such a trial. Gastric mucosal perfusion was assessed using gastric intramucosal pH (pH(i)) by tonometry and laser-Doppler flowmetry. During the weaning attempt, the failure weaning group developed a rapid, shallow breathing pattern with acute respiratory acidosis. The pH(i) was lower and gastric intramucosal PCO(2) (PCO(2)im) was higher in the failure weaning group than in the successful weaning group (p < 0.05). No change in gastric intramucosal-arterial PCO(2) difference was observed and a linear correlation was found between arterial PCO(2) and PCO(2)im (r(2) = 0.70; p < 0.001). Cardiac index increased in the failure group (p < 0.05) and remained stable in the success group whereas gastric mucosal blood flow decreased in the failure group (H(120) (min): -22 +/- 11% from baseline; p < 0.05) and increased in the success group (H(120) (min): 85 +/- 27% from baseline; p < 0.05). We conclude that gastric intramucosal pH changes during a 2-h weaning trial are mainly due to arterial PCO(2) variations. Nevertheless, gastric mucosal blood flow changes do occur and differ according to the weaning success or failure.
authors.affiliation: Service de Réanimation Médicale et Médecine Hyperbare, Hôpital Calmette, Centre Hospitalier et Universitaire de Lille, Lille, France.
authors.forename: N
authors.initials: N
authors.lastname: Bocquillon
authors.forename: D
authors.initials: D
authors.lastname: Mathieu
authors.forename: R
authors.initials: R
authors.lastname: Neviere
authors.forename: N
authors.initials: N
authors.lastname: Lefebvre
authors.forename: X
authors.initials: X
authors.lastname: Marechal
authors.forename: F
authors.initials: F
authors.lastname: Wattel
mesh_terms: D000136:Acid-Base Equilibrium; D000368:Aged; D001783:Blood Flow Velocity; D002245:Carbon Dioxide / Q000097:blood; D005753:Gastric Mucosa / Q000098:blood supply* / Q000378:metabolism*; D006439:Hemodynamics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017078:Laser-Doppler Flowmetry; D008173:Lung Diseases, Obstructive / Q000378:metabolism / Q000503:physiopathology* / Q000628:therapy; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation; D012121:Respiration, Artificial; D015300:Ventilator Weaning
chemical_list: D002245:Carbon Dioxide