Finally, in the era of non-invasive Dovitinib msds strategies for PE combining several tests of various types, such as clinical evaluation, biological tests, and imaging, the evaluation of a potential role for CO2 measurement in combination with those other instruments made sense. Numerous studies are available, and although none to date has been able to prove the safety of such a non-invasive strategy incorporating capnography with a high enough level of evidence to allow its recommendation in daily clinical practice, the venue remains interesting [7-11].Where then can we place the endeavor of Rumpf and colleagues? They included 131 consecutive patients suspected of PE who had an abnormal rapid point-of-care D-dimer result in a prehospital setting and evaluated them with a combination of clinical probability of PE (two-level Wells score) and measurement of the end-tidal partial pressure of CO2 (PCO2).

PE was diagnosed in the emergency department by a positive spiral computed tomography, a high-probability V/Q scan, or a positive pulmonary angiogram. The combination of a normal end-tidal CO2 value (defined as higher than 28 mm Hg based on a receiver operating characteristic analysis) and an unlikely probability of PE had a 100% sensitivity and 100% negative predictive value (95% confidence interval [CI] 90% to 100%) for ruling out PE. In contrast, the association of a low end-tidal CO2 value (less than 28 mm Hg) and a high clinical probability had only an 86% positive predictive value for PE, and further tests would certainly be required in such patients. Clearly, those results are preliminary.

This is a small series and it was designed to set the cutoff value for this particular capnography technique and assess its feasibility in the field. Moreover, as acknowledged by the authors themselves, the clinicians who established the diagnosis were not blinded to either clinical Cilengitide assessment or capnography results. Finally, the prevalence of PE is unusually high, although this would tend to bias the results toward lower, not higher, sensitivity. But the sheer simplicity of the technique used by Rumpf and colleagues [1] is appealing and certainly deserves validation in a large-scale prospective study. Indeed, it emphasizes the use of expired CO2 alone without associated arterial PCO2, and this is a pragmatic issue in modern emergency medicine [12].