SUBLINGUAL CAPNOMETRY FOR DIAGNOSIS AND QUANTITATION OF CIRCULATORY SHOCK

We investigated sublingual tissue P-CO2 during hemorrhagic and septic shock. Hemorrhagic shock was induced in 10 rats. Sublingual P-CO2 incr eased from 45 to 125 mm Hg and arterial pressure declined from 138 to 49 mm Hg, end-tidal P-CO2 decreased from 35 to 13 mm Hg, and cardiac i ndex fell from 290 to 77 ml/min/kg. Arterial blood lactate increased f rom 0.9 to 15.8 mmol/L. Gastric P-CO2 was measured in five animals and it increased from 46 to 87 mm Hg. No significant changes were observe d in eight ''sham'' bled animals including the five animals in which g astric P-CO2 was measured. Highly significant linear correlations (p < 0.001) between sublingual P-CO2 and gastric P-CO2 (r = 0.71), cardiac index (r = -0.74), and arterial lactate (r = 0.59) were documented. W e subsequently investigated sublingual P-CO2 in five animals in which sepsis was induced by intravenous infusion of live Staphylococcus aure us. Like hemorrhagic shock, highly significant linear correlations wer e observed between end-tidal P-CO2 and cardiac index and between subli ngual P-CO2 and arterial blood lactate. Sublingual P-CO2 promises to s erve as a technically simple, noninvasive, and rapid response quantita tor of severity of circulatory shock states.