Most experimental studies on sublingual capnometry have
included hypodynamic types of circulatory shock. Even in
models of septic shock, the cardiac index started to fall at
the beginning of the experiment [52]. This has been a
limitation of models using a bolus intravenous injection of
bacteria (or endotoxin) [67]. Most of the clinical studies
did not evaluate different types of shock separately [7, 55,
56], yet it is possible that different types of shock modify
PslCO2 values in different ways. This may also contribute
to the variability in the correlations between PslCO2 and
other markers of tissue perfusion in the various studies, as
suggested by Rackow et al.