Objective: To examine the relationship between sublingual Pco(2) (Pslco(2))
and other indexes of tissue perfusion.
Design: Prospective observational study.
Setting: Medical and coronary ICUs in a tertiary-care teaching hospital.
Subjects: Twenty-five patients with circulatory failure, 19 patients with s
epsis, and 6 patients with cardiac failure.
Measurements and main results: Pslco2, gastric intramucosal Pco(2) (Pico(2)
), arterial lactate concentration, systemic oxygen delivery, and systemic o
xygen consumption were measured at baseline and at 1, 3, 6, 12, and 24 h af
ter the beginning of the study. Pslco2 and the Pslco(2)-Paco(2) gradient we
re increased but not significantly different in nonsurvivors compared to su
rvivors at baseline. At 24 h, the mean (+/-SE) Pslco(2) was 45 +/- 4 mm Hg
in survivors and 61 +/- 4 mm Hg in nonsurvivors (p = 0.06), while the Pslco
(2)-Paco(2) gradient was 14 +/- 3 mm Hg in survivors and 29 +/- 4 nun Hg in
nonsurvivors (p < 0.05). No other significant differences in survivors and
nonsurvivors were observed in any other index of perfusion. For all patien
ts, the correlations between Pslco(2) and Pico(2) (r = 0.459; p < 0.05) and
cardiac index (r = 0.285; p < 0.05) were observed. The Pslco2-Paco2 gradie
nt also was correlated with the Pico(2)-Paco(2) gradient (r = 0.323; p < 0.
05). When patients were placed into subsets of sepsis and cardiac failure,
the strength of the correlations increased in the patients with cardiac fai
lure (Pslco(2) vs lactate, r = 0.611 and p < 0.05; Pslco(2) vs Pico(2), r =
0.613 and p < 0.05; Pslco(2) vs Pico(2)-Paco(2) gradient, r = 0.648 and p
< 0.05).
Conclusion: Pslco2 correlated best with Picot and arterial lactate concentr
ation in patients with cardiac failure. Pslco2, and the Pslco2-Paco2 gradie
nt may, be useful as indexes of the severity of perfusion failure.