The Analysis of Pulse Pressure Variations during Spontaneous Breathing

Abstract

Volume expansion (VE) is one of the main symptomatic treatment of critically ill patients with hemodynamic shock. Although the aim of VE is to increase stroke volume (SV) and organ perfusion, inappropriate administration may lead to poor outcome. During invasive mechanical ventilation, dynamic parameters based on cardiopulmonary interactions have been developed in order to predict the hemodynamic response to VE. Variations in SV and estimates like pulse pressure variation (PPV) can be used in clinical practice in highly selected patients, with regular cardiac rhythm, undergoing mechanical ventilation without spontaneous respiratory cycles. Several studies have tested the diagnostic accuracy of PPV to predict fluid responsiveness in nonintubated, spontaneously breathing patients. Analysis methods for PPV are currently either too complex or inaccurate to be recommended in clinical practice. The aim of this review is to present the rationale for, and the limitations of the use of PPV to predict fluid responsiveness in critically ill spontaneously breathing patients without mechanical ventilation.