Increased tissue oxygen extraction and acidosis with progressive severity of sepsis

David W. Hart, David L. Chinkes, Dennis C. Gore

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Background. Lactic acidosis and increased production of CO2 are common in septic shock. Presumably, both acidosis and CO2 enhance the release of oxygen from hemoglobin. The purpose of this study was to assess the relationship of oxygen utilization, CO2 production, acidosis, and hemoglobin oxygen (Hgb-O2) dissociation with progressive severity of sepsis to shock. Materials and methods. Femoral arterial and vein, hepatic vein, portal vein, and pulmonary artery catheters were placed in 16 anesthetized swine. Organ blood flow was determined by timed injections of colored microspheres. After baseline measurements, Pseudomonas aeruginosa was infused in eight animals. This bacterial slurry was continued inciting a progression of sepsis to shock. Eight animals served as instrumented controls. Results. With sepsis and shock, there was a progressive decrease in pH and an increase in pCO2 in plasma with all sampling sites (P < 0.01 septic shock versus baseline versus control). Blood flow to the liver and intestines increased with sepsis (P < 0.01) but then returned to near baseline control values during shock. VO2 and/or percent O2 extraction increased with sepsis and septic shock for the whole body and for the liver, intestine and leg (P < 0.01). There was a strong correlation between venous O2 saturation, acidosis, and pCO2 to percent O2 extraction (r > 60; P < 0.0001). However, calculated P50 values for Hgb-O2 dissociation remained unchanged. Conclusions. This study demonstrates that increased oxygen extraction in severe sepsis is related to a fall in tissue oxygen availability and not related to any allosteric change in Hgb-O2 dissociation. Therefore, acidosis and hypercapnia do not have a demonstrable effect on altering oxygen availability during sepsis.

Original languageEnglish (US)
Pages (from-to)49-58
Number of pages10
JournalJournal of Surgical Research
Volume112
Issue number1
DOIs
StatePublished - Jun 1 2003

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Keywords

  • Carbon dioxide
  • Lactate
  • O utilization
  • Perfusion
  • Septic shock

ASJC Scopus subject areas

  • Surgery

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