PEEP-INDUCED TRICUSPID REGURGITATION

Objective: To determine the presence of tricuspid regurgitation (TR) i n patients affected by acute lung injury (ALI) and the adult respirato ry distress syndrome (ARDS) during mechanical ventilation with positiv e end-expiratory pressure (PEEP). Design: A prospective clinical study . Setting: 10-bed general intensive care unit in a University Hospital . Patients: 7 consecutive patients an age 44.7 +/- 8.6 years with a di agnosis of ALI or ARDS were studied. All were on mechanical ventilatio n with PEEP. Interventions: PEEP was increased in steps of 5 cm H2O un til the appearance of TR or up to a limit of 20 cm H2O. Measurements a nn results: Right atrial pressure, pulmonary artery pressure, and wedg e pressure were measured and cardiac output was determined by thermodi lution. TR was graded from 0 to 3. Standard 2D echocardiographic and p ulsed-wave images were obtained at each level of PEEP. PEEP was increa sed from 4 +/- 3 to 17 +/- 2 cm H2O. Mean PAP increased from 27.7 +/- 2.9 to 36.7 +/- 3.5 mm Hg (p < 0.02) when PEEP was increased. Five pat ients had competent valves and two had mild TR at baseline. In six out of the seven, TR either developed or increased when PEEP was increase d. Conclusions: Our study demonstrated the development of TR after the use of PEEP in patients with ALI and ARDS as a consequence of pulmona ry hypertension and right ventricular overloading. Since TR may random ly affect cardiac output values and derived parameters, the assessment of cardiac performance by some techniques such as thermodilution shou ld be used with caution.