Method | Threshold | Main limits |
---|---|---|
PPV (pulse pressure variation) SVV (stroke volume variation) | 12% | Difficult to use in the following cases: patients with spontaneous breathing, patients with arrhythmia, patients with low tidal ventilation, and patients with low lung compliance |
IVC diameter fluctuations | 12% | Difficult to use in the following cases: patients with spontaneous breathing, patients with arrhythmia, and patients with low lung compliance |
SVC diameter fluctuations | 12–40% | Requires transesophageal echocardiography. Difficult to use in the following cases: patients with spontaneous breathing, patients with low tidal ventilation, and patients with low lung compliance |
PLR (passive leg raising) | 10% | Cardiac output is to be directly measured Difficult to use in the following cases: patients with lower limb defects, pregnant women, patients receiving vasoactive drugs, and patients with increased intra-abdominal pressure |
EEO (end-expiratory occlusion test) | 5% | Difficult to use in the following cases: non-intubated patients and patients who cannot hold their breath for more than 15 s |
Low-dose fluid challenge (100 mL) | 6–10% | Cardiac output needs to be measured directly and accurately |
Fluid challenge (500 mL) | 15% | Risk of fluid overload if repeated. Cardiac output needs to be measured directly |