Effect Inverse Ratio Ventilation on Arterial Oxygenation and Respiratory Mechanics During lapaLAR

Study Overview
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Brief Summary
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Changes of inspiration: expiration ration from 1:2 to 1:1 could improve the arterial oxygenation and respiratory mechanics

Detailed Description
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Inverse ratio ventilation already known as effective to improve the oxygenation and respiratory mechanics in the ARDS patients. Recently, there were report of decrease in airway pressure and improve in respiratory compliance during inverse ration ventilation undergoing one lung ventilation. We hypothesized that changes of inspiration and expiration ratio from 1:2 to 1:1 could improve the arterial oxygenation and respiratory mechanics in the patients who undergoing laparoscopic low anterior resection. However, prolonged inspiratory time might compromise cerebral perfusion pressure due to an elevation in central venous pressure and concomitant reductions in mean arterial pressure.

Official Title
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Effect of Inverse Ratioventilation on Laparoscopic Low Anterior Resection

Conditions
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Colorectal Neoplasms

Intervention / Treatment
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* Other: inverse IE


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: colorectal cancer Exclusion Criteria: obesity (BMI>35), uncontrolled hypertension, coronary artery disease, uncompensated cardiovascular disease, current respiratory disease, open procedure

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 70 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: Inverse IE<br>in only one group, inspiration to expiration ratio 1:2 to 1:1 will be applied during pneumoperitoneum | Other: inverse IE<br>* in only one group changes of I:E ratio would be applied<br>* Other names: inverse I:E;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| arterial oxygenation (PaO2) | sampling for arterial blood from arterial cannular will be analyzed 10 min after anesthetic induction, 20 min after pneumoperitoneum, 40 min after pneumoperitoneum and operation end. | baseline PaO2- 2 hour after pneumoperitoneum | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| cerebral perfusion pressure | cerebral perfusion pressure would calculate as mean arterial pressure-central venous pressure from immediately before pneumoperitoneum in the Trendelenburg position, every 5 min up to 20 after I:E ratio 1:1. | immediately before pneumoperitoneum in the Trendelenburg position, every 5 min up to 20 after I:E ratio 1:1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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laparoscopy, Trendelenburg Position, ventilation