Table 3 Thresholds and limits of dynamic indicators

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