Investigators design this prospective observational study to exam the ability of hypotension prediction index in predicting intraoperative hypotension events in each phase of thoracic surgery

Hypotension prediction index is a novel introduced monitoring-tool that aims to predict hypotension events before their occurence, and has been reported to have superior predictive ability than the commonly measured perioperative hemodynamic variables. To date, there is no information regarding its ability to predict hypotension events in each phase of thoracic surgery.

Inclusion Criteria:

• adults undergoing scheduled VATS surgery

Exclusion Criteria:

• pregnant women
• patients in intensive care units
• patients with the underlying disease including respiratory failure(FEV1/FVC < 70 % and FEV1 < 50%), heart failure(NYHA score =III、IV), kidney failure(eGFR< 60 ml.min-1.1.73m-2), liver failure
• patients with ongoing infection

adults undergoing scheduled VATS surgery