title: Effect of dobutamine on oxygen consumption and gastric mucosal pH in septic patients.
abstract: Decreases in gastric mucosal pH (pHi) are associated with splanchnic hypoxia in animals and with increased mortality in patients. In the present study we measured changes in gastric pHi with a tonometer in septic patients after a short-term infusion of dobutamine. These changes were compared with concurrent alterations in systemic O2 consumption (VO2) and arterial lactate. Twenty-one patients admitted sequentially to a medical intensive care unit with sepsis and gastric pHi < 7.32 were prospectively separated into a normal lactate group (< or = 2.2 mM; n = 10) and an elevated lactate group (> 2.2 mM; n = 11). Dobutamine HCl was infused intravenously at 5 micrograms/kg/min for approximately 3 h and then increased to 10 micrograms/kg/min. Measurements were obtained after each increase in the dose of dobutamine. Dobutamine infused at 10 micrograms/kg/min produced increases in O2 transport in both groups (p < 0.05) whereas systemic O2 consumption remained unchanged. These changes were accompanied by decreases in the arterial lactate concentration of the elevated lactate group (p < 0.01). Arterial lactate remained constant in the normal lactate group. Gastric pHi increased in both groups when dobutamine was infused at 5 micrograms/kg/min (p < 0.01), and then again at 10 micrograms/kg/min (p < 0.05). These results imply that regional tissue hypoxia, as characterized by a low gastric pHi, may be present in septic patients with normal arterial lactate concentration. Moreover, a rise in gastric pHi in response to increases in systemic O2 transport may be a better indicator of regional hypoxia in septic patients than related increases in systemic VO2.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, University of Texas Health Science Center, Houston 77030.
authors.forename: G
authors.initials: G
authors.lastname: Gutierrez
authors.forename: C
authors.initials: C
authors.lastname: Clark
authors.forename: S D
authors.initials: SD
authors.lastname: Brown
authors.forename: K
authors.initials: K
authors.lastname: Price
authors.forename: L
authors.initials: L
authors.lastname: Ortiz
authors.forename: C
authors.initials: C
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001424:Bacterial Infections / Q000097:blood / Q000378:metabolism*; D004280:Dobutamine / Q000494:pharmacology*; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000097:blood; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000187:drug effects*
chemical_list: D007773:Lactates; D004280:Dobutamine; D010100:Oxygen