TY - JOUR
T1 - Increased tissue oxygen extraction and acidosis with progressive severity of sepsis
AU - Hart, David W.
AU - Chinkes, David L.
AU - Gore, Dennis C.
PY - 2003/6/1
Y1 - 2003/6/1
N2 - 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.
AB - 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.
KW - Carbon dioxide
KW - Lactate
KW - O utilization
KW - Perfusion
KW - Septic shock
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U2 - 10.1016/S0022-4804(03)00141-0
DO - 10.1016/S0022-4804(03)00141-0
M3 - Article
C2 - 12873433
AN - SCOPUS:0038303345
VL - 112
SP - 49
EP - 58
JO - Journal of Surgical Research
JF - Journal of Surgical Research
SN - 0022-4804
IS - 1
ER -