Increased production of vasodilating substances such as NO plays an important role in the development of vasoplegic syndrome caused by obstructive jaundice.Methylene blue plays a role in raising blood pressure by inhibiting the vasodilator Nitric Oxide (NO)

The level of circulating hydrogen sulfide (H2S) in patients with obstructive jaundice is significantly increased. As a direct opener of KATP channels in vivo, H2S also has diastolic peripheral vasculature . H2S participates in the occurrence of vasoplegic syndrome in patients with obstructive jaundice by interacting with NO. However, it is unclear whether methylene blue can relieve vasoplegic syndrome in patients with obstructive jaundice by inhibiting the vasodilating effect of substances such as H2S and NO.

Therefore, this clinical study intends to include patients with obstructive jaundice, using randomized, controlled, prospective study to explore the effect of methylene blue on the occurrence of vasoplegic syndrome, organ function and prognosis in patients with obstructive jaundice.

Inclusion Criteria:

1. Age: 18~70 years old;
2. ASA grade I~III;
3. Ability to comply with research protocols;
4. Patients with obstructive jaundice: patients with total bilirubin greater than 50umol/L;
5. Voluntarily participate in the study and sign the informed consent form. -

Exclusion Criteria:

1. ASA IV~V grade;
2. women during lactation and pregnancy;
3. Patients with severe heart disease or lung disease before surgery;
4. Participating in other trials in the last 2 months;
5. Those whose mental state cannot cooperate, who suffer from mental illness, have no self-control, and cannot express clearly;
6. Those who refuse to sign the informed consent form. -