Table 1 Summary of methods predicting preload responsiveness with diagnostic threshold and limitations
Method | Threshold | Main limitations |
|---|---|---|
Pulse pressure/stroke volume variations [22] | 12% | Cannot be used in case of spontaneous breathing, cardiac arrhythmias, low tidal volume/lung compliance |
Inferior vena cava diameter variations [44] | 12% | Cannot be used in case of spontaneous breathing, low tidal volume/lung compliance |
Superior vena caval diameter variations [44] | 36%* | Requires performing transesophageal Doppler Cannot be used in case of spontaneous breathing, low tidal volume/lung compliance |
Passive leg raising [55] | 10% | Requires a direct measurement of cardiac output |
End-expiratory occlusion test [75] | 5% | Cannot be used in non-intubated patients Cannot be used in patients who interrupt a 15-s respiratory hold |
“Mini”-fluid challenge (100 mL) [84] | 6%** | Requires a precise technique for measuring cardiac output |
“Conventional” fluid challenge (500 mL) [81] | 15% | Requires a direct measurement of cardiac output Induces fluid overload if repeated |