The MEC90 of Epidural Ropivacaine Blunting Hemodynamic Changes to Pneumoperitoneum

Study Overview
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Brief Summary
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Investigators want to find the concentration of epidural ropivacaine, which can block hemodynamic changes in the onset of pneumoperitoneum in the laparoscopic gastrectomy.

Detailed Description
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According to previous patient's response, the investigators will allocate the concentration of ropivacaine of next patient during Co2 insufflation. And, for this allocation of concentration of ropivacaine, the investigators use biased coin design up-and-down method. Based on the practices, the starting concentration is 0.375 %, and the step size of concentration is 0.125%.

Official Title
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The MEC90 of Epidural Ropivacaine Blunting Hemodynamic Changes to Pneumoperitoneum in the Patients Undergoing Laparoscopic Gastrectomy

Conditions
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Laparoscopic Gastrectomy

Intervention / Treatment
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* Drug: Ropivacaine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing laparoscopic gastrectomy that require pneumoperitoneum patients who has epidural catheter to manage postoperative pain control patients who agree to our study Exclusion Criteria: patients who don't agree to our study BMI<16.0 or BMI>35 cardiovascular disease, pulmonary disease, renal disease alcoholic abuser or drug abuser any use of local anesthetics or drugs which have an influence on cardiovascular system from beginning of induction

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: laparoscopic gastrectomy with pneumoperitoneum<br> | Drug: Ropivacaine<br>* According to previous patient's response, the investigators will allocate the concentration of ropivacaine of next patient during Co2 insufflation. And, for this allocation of concentration of ropivacaine the investigators use biased coin design up-and-down method.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes from baseline in heart rate (bpm) after CO2 insufflation | Heart rate will be recorded before anesthesia induction, during CO2 insufflation, after Co2 insufflation. The mean value of heart rate before anesthesia induction will be regarded as the baseline values. If maximum heart rate after Co2 insufflation increased by >20% from baseline value, the response will be regarded as fail and increased concentration of ropivacaine will be applied to next patient by up and down method. | immediately after CO2 insufflation : 1,2,3,4,5,6, 7, 8, 9, 10 minutes after CO2 insufflation | 
| Changes from baseline in mean arterial pressure (mmHg) after CO2 | Mean arterial pressure will be recorded before anesthesia induction, during CO2 insufflation, after Co2 insufflation. The mean value of mean arterial pressure before anesthesia induction will be regarded as the baseline values. If maximum mean arterial pressure after Co2 insufflation increased by >20% from baseline value, the response will be regarded as fail and increased concentration of ropivacaine will be applied to next patient by up and down method. | immediately after CO2 insufflation : 1,2,3,4,5,6, 7, 8, 9, 10 minutes after CO2 insufflation |