Echocardiographic assessment of pulmonary artery occlusion pressure in ventilated patients: a transoesophageal study

Background Non-invasive evaluation of left ventricular filling pressure has been scarcely studied in critically ill patients. Accordingly, we prospectively assessed the ability of transoesophageal echocardiography ( TEE) Doppler to predict an invasive pulmonary artery occlusion pressure ( PAOP) <= 18 mmHg in ventilated patients. Methods During two consecutive 3- year periods, TEE Doppler parameters were compared to right heart catheterisation derived PAOP used as reference in 88 ventilated patients, haemodynamically stable and in sinus rhythm ( age: 63 +/- 14 years; simplified acute physiologic score ( SAPS) II: 45 +/- 12). During the initial period ( protocol A), threshold values of pulsed-wave Doppler parameters to predict an invasive PAOP +/- 18 mmHg were determined in 56 patients. Derived Doppler values were prospectively tested during the subsequent period ( protocol B) in 32 patients. Results In protocol A, Doppler parameters had similar area under the receiver operating characteristic ( ROC) curve. In protocol B, mitral E/ A <= 1.4, pulmonary vein S/ D > 0.65 and systolic fraction > 44% best predicted an invasive PAOP <= 18 mmHg. Lateral E/ E' <= 8.0 or E/ Vp <= 1.7 predicted a PAOP <= 18 mmHg with a sensitivity of 83% and 80%, and a specificity of 88% and 100%, respectively. Areas under ROC curves of lateral E/ E' and E/ Vp were similar ( 0.91 +/- 0.07 vs 0.92 +/- 0.07: p = 0.53), and not significantly different from those of pulsed-wave Doppler indices. Conclusion TEE accurately predicts invasive PAOP = 18 mmHg in ventilated patients. This further increases its diagnostic value in patients with suspected acute lung injury/ acute respiratory distress syndrome.