The Effect of Different I:E Ratio on Gas Exchange of Patients Undergoing Gynecologic Laparoscopic Surgery With Trendelenburg Position

Study Overview
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Brief Summary
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In patients undergoing gynecologic laparoscopic surgery with trendelenburg position, the disturbance of pulmonary gas exchange frequently occurs due to high intra-abdominal pressure. The investigators tried to evaluate the effect of various inspiratory to expiratory ratio on pulmonary gas exchange by randomized controlled trial.

Detailed Description
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In patients undergoing gynecologic laparoscopic surgery with trendelenburg position, the disturbance of pulmonary gas exchange frequently occurs due to high intra-abdominal pressure. During the laparoscopic surgery with abdominal gas insufflation, gas exchange disturbance such as CO2 retention, hypoxemia occurs in addition to high plateau airway pressure. The usual strategy against these kinds of problem is pressure-controlled ventilation. However, the gas exchange problem especially CO2 retention can not be solved in some cases. The inverse-ratio ventilation (IRV), which prolongs the inspiratory time greater than expiratory time, can be applied for adult respiratory distress syndrome. The efficacy of IRV is to improve gas-exchange status by increasing mean airway pressure and alveolar recruitment. There have been several clinical investigations which applied IRV during general anesthesia. However, there have been debates about the effect of IRV during general anesthesia. Therefore, we tried to apply the IRV for subjects undergoing laparoscopic surgery, and evaluate the effect of different I:E ratio on the pulmonary gas exchange and respiratory mechanics.

Official Title
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The Effect of Different I:E Ratio on Gas Exchange of Patients Undergoing Gynecologic Laparoscopic Surgery With Trendelenburg Position

Conditions
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Uterine Myoma, Ovarian Cyst, Laparoscopic Gynecologic Surgery

Intervention / Treatment
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* Procedure: conventional I:E ratio
* Procedure: 1:1 ratio
* Procedure: 2:1 group
* Procedure: external PEEP


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing elective gynecologic laparoscopic surgery the duration of pneumoperitoneum during laparoscopic surgery is more than 40 minutes Exclusion Criteria: ASA (American society of anesthesiologists) classification of the subjects more than III. Age under 20, or more than 65 years. Past history of pneumothorax, COPD, asthma. Patients with ischemic heart disease, valvular heart disease.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 1:2 group<br>conventional I:E ratio group, inspiratory time : expiratory time = 1:1 | Procedure: conventional I:E ratio<br>* conventional I:E ratio of 1:2 is applied.<br>|
| Experimental: 1:1 group<br>1:1 I:E ratio group, inspiratory time : expiratory time = 1:1 | Procedure: 1:1 ratio<br>* I:E ratio of 1:1 is applied.<br>|
| Experimental: 2:1 group<br>inverse ratio group, inspiratory time : expiratory time = 2:1 | Procedure: 2:1 group<br>* Inverse I:E ratio of 2:1 is applied.<br>|
| Active Comparator: 1:2 PEEP group<br>I:E ratio of 1:2 with external PEEP of 5 cm H2O | Procedure: conventional I:E ratio<br>* conventional I:E ratio of 1:2 is applied.<br>Procedure: external PEEP<br>* external positive end-expiratory pressure of 5 cmH2O is applied.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| arterial CO2 partial pressure | arteial CO2 partial pressure | 10 minutes after induction of general anesthesia | 
| arterial CO2 partial pressure | arteial CO2 partial pressure | 30 minutes after start of pneumoperitoneum | 
| arterial CO2 partial pressure | arteial CO2 partial pressure | 60 minutes after start of pneumoperitoneum | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| arterial O2 partial pressure | arterial O2 partial pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| Mean airway pressure | Mean airway pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| tidal volume (setting) | tidal volume (setting) | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| hemodynamic parameters | systolic/ diastolic blood pressure, heart rate, mean blood pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| end-tidal CO2 partial pressure | end-tidal CO2 partial pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| respiratory compliance | Dynamic compliance, Static compliance | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| Dead space | physiologic dead space / tidal volume (VD/VT) | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| work of breathing | work of breathing | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| peak inspiratory pressure | peak inspiratory pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| plateau pressure | plateau pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| positive end-expiratory pressure | positive end-expiratory pressure | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| tidal volume (exhaled) | tidal volume (exhaled) | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 
| minute ventilation | minute ventilation | 10 min after induction, 30 and 60 min after start of pneumoperitoneum | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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laparoscopic gynecologic surgery, gas exchange, inspiratory time, expiratory time, I:E ratio