ET CO2 to help exclude PE?

Now that’s an interesting idea. It looks like it could come in handy. From a recent study:

...consecutive patients with suspected pulmonary embolisms (PEs) were enrolled over 6 months in 2012. Symptoms, demographic date, Wells’ score, D-dimer levels and the gold standard computed tomography pulmonary angiogram (CTPA) results were collated for analysis. ETCO2 was measured within 24 hours of presentation in all 100 patients. Patient ages ranged from 18 years to 93 years. PE was diagnosed in 38% of cases…All patients positive for a PE obtained an ETCO2 less than 4.3 kPa (32.3 mmHg). This point (4.3 kPa) had a sensitivity and specificity (100% and 68% respectively), with a negative predictive value of 100% and positive predictive value of 66%. ETCO2 may reliably be used to screen and exclude patients with suspected PEs.

Via Hospital Medicine Virtual Journal Club.