**4. The hole of pulmonary arterial hypertension and right ventricular dysfunction in ARDS severity stratification**

Hemodynamic data from the ARDSnet Fluids and Catheter Therapy Trial (FACCT) [6] that analyzed 475 patients randomized to receive a pulmonary artery catheter for ARDS management, none of the baseline measures of cardiopulmonary dysfunction distinguished survivors from nonsurvivors. When the authors measured the transpulmonary gradient (TGP), they observed that 73% of the ARDS patients monitored with the Swan-Ganz had an elevated TGP (>12 mm Hg). Patients with a TPG *>* 12 mm Hg had a significantly greater mortality rate than patients with a TPG *<* 12 mm Hg (30 vs. 19%; *P =* 0.02). In multivariate analysis, an elevated TPG and a high PVRi remained an independent predictor of an adverse outcome in this ARDS population. In a recent, prospective and observational study in an academic medical intensive care unit in France [7], 226 consecutive patients with moderate to severe ARDS ventilated who received a protective ventilation (plateau pressure less than 30 cm H<sup>2</sup> O and mean PEEP of 8.8 ± 3.6 cm H2 O, underwent transesophageal echocardiography (TEE) within the first 3 days after the diagnosis of ARDS. Cor pulmonale (dilated right ventricle associated with septal dyskinesia), was detected in 49 patients (prevalence of 22%; 95% confidence interval, 16–27%). Patients who had cor pulmonale presented a significantly higher 28-day mortality rate (60 vs. 36%, *P* < 0.01) compared with the ARDS patients without cor pulmonale. Sepsis and higher values of driving pressure were associated with the presence of cor pulmonale that was an independent risk factor for 28-day mortality in their population. Taking these results into consideration, a subgroup of ARDS severity stratification: ARDS with right ventricular dysfunction should be proposed especially because different ventilatory strategies (prone position, low driving pressures, titrated PEEP levels), distinct pharmacologic therapy (pulmonary artery vasodilators) should be tested in order to improve prognosis of this subgroup of ARDS patients [4].
