Gastric and esophageal intramucosal PCO2 (PiCO2) during endotoxemia: assessment of raw PiCO2 and PCO2 gradients as indicators of hypoperfusion in a canine model of septic shock.
OBJECTIVE
To validate capnometric recirculating gas tonometry (CRGT) for continuously monitoring gut intramucosal PCO2 (PiCO2) in a septic shock model, and to compare gastric vs esophageal PCO2 vs intramucosal-arterial PCO2 gradients.


METHODS
CRTG catheters were placed in the stomach and esophagus of six anesthetized dogs. A saline solution filled balloon tonometry (ST) catheter was also placed in the stomach. After equilibration, 3 mg/kg Escherichia coli lipopolysaccharide (LPS) was administered IV. PiCO2 measurements were made at 0, 45, and 90 min post-LPS by ST and continuously by CRGT.


RESULTS
Baseline PiCO2 was 41.5+/-1.9 (+/-SE) in the stomach by CRGT, 38.0+/-1.0 by ST, and 43.0+/-4.4 mm Hg in the esophagus (p=not significant). Gastric PiCO2 by CRGT increased to 47.0+/-2.4 mm Hg by 25 min post-LPS (p<0.05), whereas gastric (ST) and esophageal PiCO2 increased significantly by 45 min post-LPS. Good agreement was observed between gastric CRGT and ST measurements (mean bias, 1.3 mm Hg). The PiCO2-PaCO2 gradient increased post-LPS, but was significant only for gastric CRGT measurements 90 min post-LPS infusion.


CONCLUSIONS
CRGT provided continuous gastric PiCO2 measurements that were in close agreement with ST but detected changes earlier than the conventional technique. Continuous esophageal PiCO2 represents a valid alternative for assessing gastric PiCO2.
Guzman
J A
JA
Section of Critical Care Medicine, Wayne State University School of Medicine, Detroit, USA.
Lacoma
F J
FJ
Kruse
J A
JA
D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D004195:Disease Models, Animal; D004285:Dogs; D019446:Endotoxemia / Q000378:metabolism* / Q000503:physiopathology; D004947:Esophagus / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D006439:Hemodynamics; D006863:Hydrogen-Ion Concentration; D008991:Monitoring, Physiologic / Q000379:methods; D009092:Mucous Membrane; D010100:Oxygen / Q000032:analysis; D012772:Shock, Septic / Q000378:metabolism* / Q000503:physiopathology
D002245:Carbon Dioxide; D010100:Oxygen