Clinical relevance of pulse pressure variations for predicting fluid responsiveness in mechanically ventilated intensive care unit patients: the grey zone approach

Abstract

IntroductionPulse pressure variation (PPV) has been shown to predict fluid responsiveness in ventilated intensive care unit (ICU) patients. The present study was aimed at assessing the diagnostic accuracy of PPV for prediction of fluid responsiveness by using the grey zone approach in a large population.MethodsThe study pooled data of 556 patients from nine French ICUs. Hemodynamic (PPV, central venous pressure (CVP) and cardiac output) and ventilator variables were recorded. Responders were defined as patients increasing their stroke volume more than or equal to 15% after fluid challenge. The receiver operating characteristic (ROC) curve and grey zone were defined for PPV. The grey zone was evaluated according to the risk of fluid infusion in hypoxemic patients.ResultsFluid challenge led to increased stroke volume more than or equal to 15% in 267 patients (48%). The areas under the ROC curve of PPV and CVP were 0.73 (95% confidence interval (CI): 0.68 to 0.77) and 0.64 (95% CI 0.59 to 0.70), respectively (P <0.001). A grey zone of 4 to 17% (62% of patients) was found for PPV. A tidal volume more than or equal to 8 ml.kg−1 and a driving pressure (plateau pressure - PEEP) more than 20 cmH2O significantly improved the area under the ROC curve for PPV. When taking into account the risk of fluid infusion, the grey zone for PPV was 2 to 13%.ConclusionsIn ventilated ICU patients, PPV values between 4 and 17%, encountered in 62% patients exhibiting validity prerequisites, did not predict fluid responsiveness.

Pulse Pressure Variation Adjusted by Respiratory Changes in Pleural Pressure, Rather Than by Tidal Volume, Reliably Predicts Fluid Responsiveness in Patients With Acute Respiratory Distress Syndrome*

“…Although Monnet et al (31) showed that the low ability of ΔPP to predict FR was related to low Crs (= 1 / E RS ), others failed to demonstrate any such effect (22,32). These contradictory findings can be explained by partitioning E RS into its lung and chest wall components.…”

Pulse pressure respiratory variation to predict fluid responsiveness: From an enthusiastic to a rational view

“…All protective ventilation strategies are associated with low tidal volumes (and the frequently associated application of a high respiratory rate). Therefore, protective ventilation impairs the predictive performance of PPV [4][5][6]9], as it exposes to false negative cases [7,8,16]. Conflicting data were reported when a low tidal volume without high respiratory rate was applied [17].…”

The Diagnosis and Hemodynamic Monitoring of Circulatory Shock: Current and Future Trends

“…In conclusion, if the problem is fluid resuscitation, functional hemodynamic monitoring using dynamic parameters would be the correct option, taking into consideration the limits to which patients should be sedated, paralyzed, mechanically ventilated, with sinus rhythm and closed chest, no severe pulmonary hypertension or severe right ventricular failure [38][39][40][41]. In mechanically ventilated patients, as well as in spontaneous breathing patients, other types of dynamic parameters can be employed, namely those obtained during a passive leg raising maneuver (PLR): direct measurements of the SV or CO variations, or measurements of surrogates such as descending aortic blood flow changes [42,43].…”