The Effect of Different I:E Ratio on Gas Exchange of Patients Undergoing One-lung Ventilation for Lung Surgery

Study Overview
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Brief Summary
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Pulmonary gas exchange disturbance is a common anesthetic problem during one-lung ventilation (OLV) for thoracic surgery. The inverse-ratio ventilation (IRV), which prolongs the inspiratory time greater than expiratory time, can be applied for adult respiratory distress syndrome. The effect of IRV is to improve gas-exchange status by increasing mean airway pressure and alveolar recruitment. We tried to evaluate the effect of IRV during OLV with lung protective strategy.

Detailed Description
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Pulmonary gas exchange disturbance is a common anesthetic problem during one-lung ventilation (OLV) for thoracic surgery. Continuous positive airway pressure or positive end-expiratory pressure are usually applied to improve this disorder including hypoxia, but these methods are not enough. The inverse-ratio ventilation (IRV), which prolongs the inspiratory time greater than expiratory time, can be applied for adult respiratory distress syndrome. The effect of IRV is to improve gas-exchange status by increasing mean airway pressure and alveolar recruitment. The application of IRV during OLV has not been performed to our knowledge, and there is a possibility of IRV to improve oxygenation during OLV. There is a possibility of increase of auto-PEEP, or air trapping in subjects with chronic obstructive pulmonary disease, but this kind of auto-PEEP can be overcome by external PEEP. Therefore, we tried to evaluate the effect of IRV during OLV with lung protective strategy.

Official Title
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The Effect of Different I:E Ratio on Gas Exchange of Patients Undergoing One-lung Ventilation for Lung Surgery

Conditions
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Lung Cancer, One Lung Ventilation, Gas Exchange, Inverse-ratio Ventilation

Intervention / Treatment
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* Other: Conventional I:E ratio
* Other: I:E = 1:1 ratio


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing elective lung lobectomy surgery. the duration of one-lung ventilation is more than one hour. subjects with more than twenty years old. Exclusion Criteria: subjects with past history of pneumothorax, asthma Age under 20, more than 70 years. Patients with ischemic heart disease, valvular heart disease patients with hemodynamic unstability

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

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


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 | Other: Conventional I:E ratio<br>* conventional I:E ratio of 1:2 is applied. Ventilator : Datex-Ohmeda Aestiva/5 ® model<br>* Other names: Ventilator : Datex-Ohmeda Aestiva/5 ® model;|
| Experimental: 1:1 group<br>inspiratory time : expiratory time = 1:1 | Other: I:E = 1:1 ratio<br>* I:E ratio of 1:1 is applied Ventilator : Datex-Ohmeda Aestiva/5 ® model<br>* Other names: Ventilator : Datex-Ohmeda Aestiva/5 ® model;|

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 one-lung ventilation | 
| arterial CO2 partial pressure | arteial CO2 partial pressure | 60 minutes after start of one-lung ventilation | 
| arterial CO2 partial pressure | arteial CO2 partial pressure | 15 min after restart of TLV | 
| arterial CO2 partial pressure | arteial CO2 partial pressure | 1 hour after the end of surgery | 

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 one-lung ventilation, 15 min after restart of two-lung ventilation, 1 hour after the end of surgery | 
| Mean airway pressure | Mean airway pressure | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| tidal volume (exhaled) | tidal volume (exhaled) | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| hemodynamic parameters | systolic/ diastolic blood pressure, heart rate, mean blood pressure | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| end-tidal CO2 partial pressure | end-tidal CO2 partial pressure | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| respiratory compliance | Dynamic compliance, Static compliance | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| Dead space | physiologic dead space / tidal volume (VD/VT) | 10 min after induction, 30 and 60 min after start of one lung ventilation, 15 min after restart of two-lung ventilation | 
| work of breathing | work of breathing | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| peak inspiratory pressure | peak inspiratory pressure | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| plateau pressure | plateau pressure | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| positive end-expiratory pressure | positive end-expiratory pressure | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 
| minute ventilation | minute ventilation | 10 min after induction, 30 and 60 min after start of one-lung ventilation, 15 min after restart of two-lung ventilation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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one lung ventilation, gas exchange, inverse-ratio ventilation