Pulse pressure variations to predict fluid responsiveness: influence of tidal volume

Abstract

DeltaPP is a reliable predictor of fluid responsiveness in mechanically ventilated patients only when tidal volume is at least 8 ml/kg.

Assessment of Volume Responsiveness During Mechanical Ventilation: Recent Advances

“…In the case of low tidal volume, the small variations in intrathoracic pressure may not be suffi cient to trigger signifi cant preload variations, even in cases of preload responsiveness. Some studies have actually shown that PPV loses its predictive value in the case of low tidal volume [24,25]. Th e changes in intravascular pressure induced by mechanical ventilation may also be reduced if the transmission of changes in alveolar pressure to the pressure of the intrathoracic structures is attenuated, e. g., in the case of low lung compliance.…”

Pulse pressure: more than 100 years of changes in stroke volume

“…In mechanically ventilated patients variations in PP and SV have been demonstrated to be good indicators of fluid responsiveness [17][18][19]. The limitation of this approach is that the patient has to be completely sedated, in sinus rhythm and ideally with tidal volumes of at least 7 ml/kg of ideal body weight [20]. This is often applicable in the operating room, but rarely in the ICU where patients are often ventilated in assisted modes maintaining a respiratory drive.…”

Assessment of loading conditions with cardiac ultrasound. A comprehensive review

“…Correct interpretation will be hampered whenever there is an occurrence of right ventricular failure [28], increased abdominal pressures [29], open chest (during or after cardiac surgery) [30,31], or too small shifts of intrathoracic pressure (low tidal volume [32,33], increased intrathoracic pressures, increased work of breathing). In contrast, an increased respiratory rate (neonates and small children) allow for a still correct estimation of fluid responsiveness by means of IVC variation [34].…”