Am. J. Respir. Crit. Care Med.,
Volume 160, Number 5, November 1999, 1555-1561
Gastric Mucosal pH and Blood Flow during Weaning
from Mechanical Ventilation in Patients with
Chronic Obstructive Pulmonary Disease
NICOLAS
BOCQUILLON,
DANIEL
MATHIEU,
RÉMI
NEVIERE,
NATHALIE
LEFEBVRE,
XAVIER
MARECHAL,
and
FRANCIS
WATTEL
Service de Réanimation Médicale et Médecine Hyperbare, Hôpital Calmette, Centre Hospitalier et Universitaire de Lille, Lille, France
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 (pHi) 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 pHi was lower and
gastric intramucosal PCO2 (PCO2im) was higher in the failure weaning group than in the successful
weaning group (p < 0.05). No change in gastric intramucosal-arterial PCO2 difference was observed
and a linear correlation was found between arterial PCO2 and PCO2im (r2 = 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 (H120 min: 
22 ± 11% from baseline; p < 0.05) and increased in the success group (H120 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 PCO2 variations. Nevertheless, gastric mucosal blood flow changes do occur and differ according to the weaning success or failure. Bocquillon N, Mathieu D, Neviere R, Lefebvre N, Marechal X, Wattel F. Gastric mucosal pH and blood flow during weaning from mechanical ventilation in patients
with chronic obstructive pulmonary disease.
