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Mathematical Model of Tissue Oxygenation in Early Sepsis
Author(s) -
Fraser Graham Mathew,
Goldman Daniel,
Ellis Christopher G.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1141.19
Subject(s) - sepsis , oxygenation , perforation , blood flow , hemodynamics , medicine , in vivo , subcutaneous tissue , skeletal muscle , lean tissue , cardiology , anatomy , anesthesia , adipose tissue , pathology , biology , materials science , microbiology and biotechnology , punching , metallurgy
The defining characteristic of sepsis is a progressive microvascular dysfunction remote to the locus of infection. Our objective was to quantify the time course of changing tissue PO 2 due to microvascular injury in early sepsis using an established mathematical model. Experimental data obtained from a rat cecal‐ligation and perforation (CLP) model of sepsis has demonstrated a progressive FCD loss at 2, 3 and 4 hours (11±4%, 15±1%, 21±5% SHAM vs 18±3%, 32±5%, 48±7% CLP respectively). Microvascular blood flow was recorded in skeletal muscle using dual wavelength intra‐vital video microscopy. Capillaries were analyzed at baseline in vivo for O 2 saturations and hemodynamics. Custom vascular mapping software was used to reconstruct the real geometry (length, diameter, tissue depth and connections between vessels) of the experimental network (Volume 420 × 420 × 60 μm ). A constant consumption computational model applied to the FCD conditions at each time point found mean tissue PO 2 was not different between SHAM and CLP at 2 hours (34.2±4.3 vs 33.3±4.2 mmHg) or 3 hours (33.0±4.3 vs 31.2±4.5 mmHg) post. At 4 hours tissue PO 2 was significantly different between SHAM and CLP (32.7±4.3 vs 25.9±6.5 mmHg, p < 0.01). This simulation suggests that a substantial FCD loss precedes a significant decrease in tissue oxygenation due to diffusional exchange between adjacent capillaries. Supported by CIHR grant to DG and CGE.