• M H Weil, Y Nakagawa, W Tang, Y Sato, F Ercoli, R Finegan, G Grayman, and J Bisera.
• Institute of Critical Care Medicine, Palm Springs, CA 92262-5309, USA. Weilm@aol.com
• Crit. Care Med. 1999 Jul 1;27(7):1225-9.

ObjectiveTo investigate the feasibility and predictive value of sublingual Pco2 (P(SL)CO2) measurements as a noninvasive and early indicator of systemic perfusion failure.DesignA prospective, criterion study.SettingEmergency department and medical and surgical intensive care units of an urban community medical center.Participants And PatientsFive normal human volunteers and 46 patients with acutely life-threatening illness or injuries.InterventionsIntra-arterial or automated cuff blood pressure and arterial blood lactate (LAC) were measured concurrently with P(SL)CO2.ResultsP(SL)CO2 in five healthy volunteers was 45.2 +/- 0.7 mm Hg (mean +/- sD). Twenty-six patients with physical signs of circulatory shock and LAC >2.5 mmol/L had a P(SL)CO2 of 81 +/- 24 mm Hg. This contrasted with patients admitted without clinical signs of shock and LAC of <2.5 mmol/L who had a P(SL)CO2 of 53 +/- 8 mm Hg (p < .001). The initial P(SL)CO2 of 12 patients who died before recovery from shock was 93 +/- 27 mm Hg, and this contrasted with 58 +/- 11 mm Hg (p < .001) in hospital survivors. Increases in P(SL)CO2 were correlated with increases in LAC (r2 = .84; p < .001). When P(SL)CO2 exceeded a threshold of 70 mm Hg, its positive predictive value for the presence of physical signs of circulatory shock was 1.00. When it was <70 mm Hg, it predicted survival with a predictive value of 0.93.ConclusionP(SL)CO2 may serve as a technically simple and noninvasive clinical measurement for the diagnosis and estimation of the severity of circulatory shock states.

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