Ventilatory Strategies After Cardiopulmonary Bypass Evaluated by Electrical Impedance Tomography

Study Overview
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Brief Summary
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Pulmonary complications after cardiac surgeries are common. It is one of the most crucial concerns of cardiac surgeons and anesthesiologists. These adverse events may vary from a mild respiratory dysfunction to acute respiratory distress syndrome (ARDS). One of the most public reasons of these complications is atelectasis that would result in hypoxia and pneumonia. Any of these adverse events rises the prevalence of morbidity and mortality. The chief inducing causes for atelectasis are CPB and dropped blood perfusion and ventilation of the lungs. The ventilation arrest is related with a high frequency of retained bronchial sections, local atelectasis, decrease in arterial O2 concentrations as a effect of surge in arteriovenous shunt, declined lung compliance, pulmonary edema and hence increased risk of nosocomial infections. Electrical Impedance Tomography (EIT) is a non-invasive, radiation-free, real time bedside imaging modality, which provide the assessment of regional gas volume and lung ventilation. EIT has been experienced in quite a lot of animal and clinical applications including optimization of mechanical ventilator strategies and recognition of respiratory adverse events. Besides, EIT has been used to recognize ideal PEEP by detection of homogenous ventilation in non-dependent and dependent lung regions. Homogeneous ventilation is key for inhibition of ventilator-induced lung injury.

Detailed Description
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The aim of this study is to use four different ventilatory strategies 【Group R : IMV(intermittent mandatory ventilation) Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) ； Group RP, Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) + PEEP : 6 cm H2O ；Group RI : Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) + Reverse IE ratio ventilation( I:E=1:1) ；Group RPI: Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) + PEEP : 6 cm H2O + Reverse IE ratio ventilation( I:E=1:1)】 to compare the beneficial in decreasing the incidence of post-operative pulmonary dysfunction after cardiac surgery including of the data of EIT, GAS , Lactate , PFR：PaO2/FiO2 ratio , cardiac index (CI) , BMI..etc . EIT were measured at two perioperative timepoints 1. after intubation at the onset of anesthesia with mechanical ventilation with 7ml/ kg (Predicted body weight) 2. at the end of surgery.

Official Title
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The Effects of Ventilatory Strategies on Pulmonary Function After Cardiopulmonary Bypass Evaluated by Electrical Impedance Tomography in Patients Undergoing Cardiac Surgery

Conditions
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Elective Cardiac Surgical Patients

Intervention / Treatment
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* Other: ventilation mode setting


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 20-80 year-old Adult patients receiving elective cardiac surgery with hypothermic CPB Exclusion Criteria: Patients were excluded if they had complicating comorbidities, such as chronic hepatic or renal insufficiency, acute cardiopulmonary failure requiring mechanical ventilation, intra-aortic balloon pump, or extracorporeal membrane oxygenation

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 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: Health Services Research
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Ventilation strategies with 4 different ventilation mode since weaning cardiopulmonary bypass (CPB), Four group were control EtCO2 between 35～45mmHg by adjusting respiratory rate, EIT Measurements were performed under supine position
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Group R<br>IMV(intermittent mandatory ventilation) Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) | Other: ventilation mode setting<br>* Ventilation strategies with 4 kinds of ventilator mode since weaning cardiopulmonary bypass (CPB), Four group were control EtCO2 between 35～45mmHg by adjusting respiratory rate, EIT Measurements were performed under supine position<br>|
| Experimental: Group RP<br>Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) + PEEP : 6 cm H2O | Other: ventilation mode setting<br>* Ventilation strategies with 4 kinds of ventilator mode since weaning cardiopulmonary bypass (CPB), Four group were control EtCO2 between 35～45mmHg by adjusting respiratory rate, EIT Measurements were performed under supine position<br>|
| Experimental: Group RI<br>Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) + Reverse IE ratio ventilation( I:E=1:1) | Other: ventilation mode setting<br>* Ventilation strategies with 4 kinds of ventilator mode since weaning cardiopulmonary bypass (CPB), Four group were control EtCO2 between 35～45mmHg by adjusting respiratory rate, EIT Measurements were performed under supine position<br>|
| Experimental: Group RPI<br>Regular Ventilation with Tidal volume with 7ml/ kg (Predicted body weight) + PEEP : 6 cm H2O + Reverse IE ratio ventilation( I:E=1:1) | Other: ventilation mode setting<br>* Ventilation strategies with 4 kinds of ventilator mode since weaning cardiopulmonary bypass (CPB), Four group were control EtCO2 between 35～45mmHg by adjusting respiratory rate, EIT Measurements were performed under supine position<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The correlation between Different ventilation mode and the relevant value of EIT | Compare the correlation between Different ventilation mode and the relevant value of EIT in the population of open heart surgery patient | since weaning cardiopulmonary bypass (CPB) to the end of surgery | 
| The demographic characteristics and relevant value of EIT | Campare the demographic characteristics and relevant value of EIT in the population of open heart surgery patient | since weaning cardiopulmonary bypass (CPB) to the end of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| If the different ventilation mode setting can improve clinical outcome | Identify the different ventilation mode setting in open heart surgery patient if can improve clinical care benifit. | since weaning cardiopulmonary bypass (CPB) to the end of surgery | 
| The correlation between heart function & oxygenation and different ventilation mode | Survey the correlation between heart function & oxygenation and different ventilation mode | since weaning cardiopulmonary bypass (CPB) to the end of surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Ventilatory strategies, Electrical Impedance Tomography, cardiac surgery