Hemodynamic Comparison Between Right Heart Catheterization and Transthoracic Echocardiography in the Critically Ill Patients: A Prospective Study

Background: Tranthoracic echocardiography (TTE) is increasingly utilized in the management of critically ill patients in whom right heart catheterization (RHC) was frequently used in the past. We tested the hypothesis that bedside TTE can substitute for RHC for determining the etiology of cardiopulmonary compromise in critically ill patients when initial clinical assessment is limited. Methods: We prospectively enrolled 51 patients from medical and surgical Intensive Care Units with unknown etiology of cardiopulmonary compromise. Patients underwent assessment of their cardiopulmonary compromise by RHC and TTE. A final clinical assessment, considered the gold standard was adjudicated by the intensivist caring for the patient. Results: There was complete agreement between TTE data and RHC data in determining the etiology of cardiopulmonary compromise as cardiac or non-cardiac in 46 (90%) of the 51 patients. The kappa statistic for the agreement between TTE data and gold standard in determining the etiology of cardiopulmonary compromise as cardiac or non-cardiac was 0.90 (95% confidence interval [CI], 0.73 to 0.98; p<0.001). The kappa statistic for the agreement between RHC data and gold standard was 0.84 (95% confidence interval [CI], 0.63 to 0.95; p < 0.001). Based on the results of the gold standard assessment, the positive predictive value and negative predictive value for TTE data determining the etiology of cardiopulmonary compromise were 93% and 97% respectively. The positive predictive value and negative predictive value for RHC data determining the etiology of cardiopulmonary compromise were 100% and 92% respectively. TTE was highly suggestive of pulmonary embolism and cardiac tamponade in three patients where RHC was not. Conclusion: In this era where transthoracic echocardiography is increasingly utilized to manage critically ill patients with cardiopulmonary compromise, we found transthoracic echocardiography to be a useful diagnostic tool in determining the etiology of cardiopulmonary compromise when initial clinical assessment is limited. While both methods can be complementary to each other, bedside transthoracic echocardiography is an acceptable non-invasive alternative to right heart catheterization in determining the etiology of cardiopulmonary compromise in most critically ill patients when initial clinical assessment is limited.