Clinical Research Directory

Inclusion Criteria: * (1) patients who have signs of tissue hypo-perfusion (increasing lactate levels, in need of vasopressor agents to maintain blood pressure, oliguria, and weak consciousness), and need to evaluate their fluid responsiveness; (2) patients who have received Pulse indicator Continuous Cardiac Output (PiCCO) monitoring ; (3) patients who are transferred into the intensive care department. Exclusion Criteria: * (1) Age \< 18 years old, or \> 75 years old (2) pregnancy or lactation; (3) refusal to sign the informed consent form for enrollment; (4) patients who are clearly unable to perform passive leg raising (PLR) (intra-abdominal pressure ≥16cmH2O, high risk of lower limb venous thrombosis, intracranial hypertension, and recent undergone abdominal or pelvic surgery); (5) patients with the contraindications of fluid resuscitation therapy ( pulmonary edema, intracranial hypertension and so on); (6) patients clinical doctors assessed as unsuitable for PLR.