title: Gastric versus duodenal feeding and gastric tonometric measurements.
abstract: OBJECTIVE
  To compare the influence of gastric and postpyloric enteral feeding on the gastric tonometric PCO2 gap (tonometric PCO2 - PaCO2).
  
  
  METHODS
  A prospective, clinical trial.
  
  
  METHODS
  Two intensive care units in a university hospital.
  
  
  METHODS
  Twenty patients undergoing mechanical ventilation and enteral feeding without catecholamines, sepsis, or sign of hypoxia.
  
  
  METHODS
  Patients were randomized to receive feeding through the tonometer (gastric group), or through a postpyloric tube (postpyloric group).
  
  
  RESULTS
  The patients received tube feeding at a rate of 50 mL/hr during 4 hrs. Baseline measurements included: mean arterial pressure, heart rate, tonometric parameters, arterial gases, and arterial lactate concentration. Except for lactate concentration, these measurements were repeated after 1 and 4 hrs of enteral feeding and 2 hrs after stopping enteral feeding. During the study, arterial pH and PaCO2 did not change. During enteral feeding, the PCO2 gap increased in the gastric group from a mean of 7+/-5 to 17+/-14 (SD) torr (0.9 0.7 to 2.3+/-1.9 kPa) (p< .O01) and did not change in the postpyloric group (5+/-5 to 3+/-1 torr [0.7+/-0.7 to 0.4+/-0.1 kPa]). Two hours after stopping enteral feeding, the PCO2 gap was still increased in the gastric group (15+/-9 vs. 7+/-5 torr [2.0+/-1.2 vs. 0.9+/-0.7 kPa]) (p < .01).
  
  
  CONCLUSIONS
  The results indicate that gastric enteral feeding increased the PCO2 gap. However, postpyloric enteral feeding does not interact with gastric tonometric measurements and should be used when using gastric tonometry in enterally fed patients.
authors.affiliation: Polyvalent Intensive Care Unit, Central Hospital, Nancy, France. b.levy@chu-nancy.fr
authors.forename: B
authors.initials: B
authors.lastname: Levy
authors.forename: P F
authors.initials: PF
authors.lastname: Perrigault
authors.forename: P
authors.initials: P
authors.lastname: Gawalkiewicz
authors.forename: F
authors.initials: F
authors.lastname: Sebire
authors.forename: M
authors.initials: M
authors.lastname: Escriva
authors.forename: P
authors.initials: P
authors.lastname: Colson
authors.forename: D
authors.initials: D
authors.lastname: Wahl
authors.forename: M
authors.initials: M
authors.lastname: Frederic
authors.forename: P E
authors.initials: PE
authors.lastname: Bollaert
authors.forename: A
authors.initials: A
authors.lastname: Larcan
mesh_terms: D000368:Aged; D015982:Bias; D001784:Blood Gas Analysis / Q000379:methods; D002245:Carbon Dioxide / Q000032:analysis* / Q000378:metabolism; D004384:Duodenoscopy; D004750:Enteral Nutrition / Q000379:methods*; D005260:Female; D005753:Gastric Mucosa / Q000098:blood supply* / Q000737:chemistry*; D005773:Gastroscopy; D006439:Hemodynamics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D002245:Carbon Dioxide