Effect of Epidural Anesthesia on Blood Flow in Arterial Anastomosis of Free Flap

Study Overview
=================
Brief Summary
-----------------
Comparing the changes of arterial anastomotic blood flow between general anesthesia alone and general anesthesia with epidural anesthesia in patients who undergoing free flap transposition using Duplex ultrasound.

Detailed Description
-----------------
Maintaining adequate blood flow is important on the success of free flap surgery. Epidural anesthesia can influence blood flow during surgery. Therefore, investigators aim to compare the effect of epidural anesthesia combined with general anesthesia and general anesthesia alone on blood flow in arterial anastomosis site of the free flap.

Official Title
-----------------
Randomized Trials of Epidural Combined With General Anesthesia Versus General Anesthesia Alone to Evaluate the Changes of Blood Flow in Arterial Anastomosis of Free Flap Using Duplex Ultrasonography

Conditions
-----------------
Free Tissue Flaps

Intervention / Treatment
-----------------
* Other: Epidural anesthesia


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients scheduled to undergo free flap transfer under general anesthesia. 18 years of age or older, under 80 years of age Those who voluntarily agreed to participate in this clinical study Exclusion Criteria: If the patient does not agree to participate in the study ASA physical status IV or higher If the patient was diagnosed with diabetes If the patient was diagnosed with chronic renal failure If the patient was diagnosed with peripheral vascular disease or hyperlipidemia If vasopressors or inotropics was used preoperatively. Contraindication of epidural anesthesia such as usage of anticoagulant or abnormalities of laboratory finding. If the researcher finds it to be inappropriate

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 79 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Epidural with general anesthesia<br>Epidural anesthesia with 0.2% ropivacaine 10 ml | Other: Epidural anesthesia<br>* After anesthesia induction, epidural catheter is inserted into lumbar epidural in epidural with general anesthesia group. A 10 ml of 0.2% ropivacaine should be given in epidural space via a catheter when anastomosis of free flap is finished in epidural with general anesthesia group.<br>* Other names: Epidural anesthesia with ropivacaine;|
| No Intervention: General anesthesia alone<br>Sevoflurane and nitrous oxide. | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maximal blood flow velocity | Maximal blood flow velocity measured by using Duplex ultrasound | 30 minutes after flap arterial anastomosis | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood volume | Blood volume measured by using Duplex ultrasound | 30 minutes after flap arterial anastomosis | 
| Arterial blood pressure | Arterial blood pressure measured monitors | 30 minutes after flap arterial anastomosis | 
| Cardiac output | Cardiac output measured monitors | 30 minutes after flap arterial anastomosis | 
| Pulse pressure variability | Pulse pressure variability measured monitors | 30 minutes after flap arterial anastomosis | 
| Body temperature | Body temperature measured monitors | 30 minutes after flap arterial anastomosis | 
| Arterial carbon dioxide concentration | Arterial carbon dioxide concentration measured arterial blood gas analysis | 30 minutes after flap arterial anastomosis | 
| Free flap failure | Free flap failure after surgery | Day 7 after free flap surgery |