Abstract Objective: Earlier reports

suggested that transthoracic (TTE) determination of the ratio of mitral inflow E wave velocity to early dia-stolic mitral annulus velocity (E/E’) measured by tissue Doppler imaging (TDI) closely approximates PAOP in cardiac patients. However, the value of E/E ’ for PAOP assessment in ICU patients has not been evaluated. This study assessed whether the E/E ’ ratio provides an accurate estimation of pulmonary artery occlusion pressure (PAOP) in mechanically ventilated ICU patients. Design and setting: Prospective, open, clinical study in the ICU of a university hospital. Patients: Twenty-three consecutive mechanically ventilated patients. Interventions: Volume expansion in 14 patients. Measurements and results: Doppler TTE or TEE mitral inflow and TDI mitral annulus velocities were determined and com-pared with PAOP measured using a Swan-Ganz catheter. Of all the Doppler variables studied the best correlations were observed between PAOP and the lateral (r=0.84) and medial (r=0.76) annulus E/E ’ ratio and remained highly significant when the analysis was restricted to TEE (r=0.91 and 0.86) or TTE (r=0.73 and 0.61). The sensitivities and specificities of estimating PAOP at 15 mmHg or higher were, respec-tively, 86 % and 81 % for lateral E/E’ above 7.5 and 76 % and 80 % for me-dial E/E ’ above 9. PAOP changes af-ter volume expansion (700±230 ml) were limited and accurately assessed by repeated E/E ’ determinations. Conclusions: In mechanically venti-lated ICU patients TTE or TEE E/E