PaCO2/ETCO2 gradient: early indicator of thrombolysis efficacy in a massive pulmonary embolism

End tidal CO2 measurement may be helpful in detecting the efficacy of throm bolysis after a massive pulmonary embolism. We report the case of a 76-year -old man with a massive pulmonary embolism, who required early intubation a nd mechanical ventilation. Thrombolysis with rtpA (total dosage: 60 mg) was initiated. During this procedure, clinical data, arterial blood gases and end-tidal CO, with a capnograph were recorded. Before thrombolysis the P(a- ET)CO2 gradient was raised to 25 mmHg. During thrombolysis, the clinical da ta improved and the P(a-ET) gradient fell to 14 mmHg. We postulate that the P(a-ET)CO2 gradient seems to be a reasonable indicator of efficacy of thro mbolysis in this setting. However. the gradient did not return to normal va lues(45 mmHg). The possible reasons for this may be that during mechanical ventilation there was a large ventilation- perfusion ratio and the cardiac output may have still reduced. With these limitations, we conclude that the P(a-ET)CO2 gradient should be evaluated as an indicator of pulmonary reper fusion in massive pulmonary embolism. (C) 2001 Elsevier Science Ireland Ltd . All rights reserved.