Correlation Analysis of the Effects of Management Pressure Goals and Control Volume Goals in Patients in Spinal Surgery

Correlation Analysis of the Effects of Management Pressure Goals (Controlled Hypotension) and Control Volume Goals (Cardiac Output, Stroke Volume Variability, Central Venous Pressure) on Intraoperative Blood and Visual Field Quality

The investigators study 160 patients undergoing spinal surgery.Participants will be randomly divided into study group and control group.The study group will receive controlled hypotension by nitroglycerin and be divided into 3 groups according to CI.

This study will be done in Guangzhou Red Cross Hospital .The investigators study 160 patients aged from 45 to 70 years,weight from 48 to 68kg classified as American Society of Anesthesiologists (ASAs) physical status Ⅰ-Ⅱ who will be candidate for posterior decompression of vertebral canal,discectomy and internal fixation by pediclescrew(one centrum).The investigators excluded patients with cardiovascular and cerebrovascular diseases,hepatic or renal dysfunction,and patients receiving drugs that interfere with coagulation before surgery.

Patients randomly divided into study group(group H,n=120)and control group (group C,n=40).The study group according to CI(Cardiac Index) levels of intraoperative hypotension period(mean of CI at T2,T3,T4) were divided into three groups: 1st group: CI: 1.5-2.0 L /(min•m2), 2nd group: CI: 2.0-3.0 L /(min•m2), 3rd group: CI: 3.0-4.0 L /(min•m2),and which CI < 1.5 or CI > 4.0 was eliminated the experimental group, which, in control group, CI< 2.5 or CI >4.0 was eliminated the experimental group.

Inclusion Criteria:

1. Aged between 35 and 70 years
2. Patients, undergoing canal decompression, intervertebral disc extraction and pedicle screw fixation (1 vertebral body)

Exclusion Criteria:

1. History of cardiovascular function

   1. congestive heart failure [CHF]
   2. coronary artery disease [CAD]
   3. cerebrovascular insuffiency)

2. poorly controlled arterial hypertension

3. pre-existing coagulation defects

4. Patients taking anticoagulatory medication including aspirin

5. Patients taking corticosteroid therapy