Predictors of mortality in acute respiratory distress syndrome - Focus on the role of right heart catheterization

Right heart catheterization (RHC) has been suspected of increasing mortalit y. The acute respiratory distress syndrome (ARDS) is a frequent reason for RHC. We designed a retrospective cohort study of 119 consecutive ARDS patie nts admitted to two medical intensive care units of tertiary care hospitals in which two different approaches are used for hemodynamic monitoring: RHC on demand (Henri Mondor Hospital [HM]) and no use of RHC (Ambroise Pare Ho spital [AP]). The study tried to identify risk factors for death, and to as sess the influence of RHC, with adjustment for the intensity of hemodynamic support as a confounding factor, using 98 patients in whom the delay betwe en onset of ARDS, use of vasopressors, and RHC did not exceed 48 h. Several variables, including septic shock, cause of ARDS, Simplified Acute Physiol ogy Score (SAPS) II, use of epinephrine/norepinephrine, and presence of RHC were entered into a logistic regression model to evaluate their independen t prognostic roles. Mortality was different at HM and AP (36 of 55 patients [65.5%] versus 16 of 43 patients [37.2%], p < 0.005), and 29 of the 35 RHC -monitored patients died (82.8%), as compared with 23 of 63 patients (36.5% ) treated without RHC (p < 0.0001). However, administration of epinephrine/ norepinephrine and a nonpulmonary cause of ARDS were each independently ass ociated with death. It is only when administration of vasopressors was omit ted from the model that RHC, septic shock, and SAPS II became independent p redictors of mortality. These results suggest that: (I) the use of vasopres sors, but not of RHC, represents an important prognostic: factor; and (2) n ot taking into account the use of these drugs may be misleading when assess ing the influence of RHC on outcome.