Ventilatory Strategies After Cardiopulmonary Bypass Evaluated by Electrical Impedance Tomography
Condition: Elective Cardiac Surgical Patients
Study type: Interventional

Summary: 
      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: 
      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.
    

Intervention name(s): ventilation mode setting
Intervention type(s): Other
Intervention description(s): 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
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention 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 (Outcomes Assessor)
Primary purpose: Health Services Research
Keywords: Ventilatory strategies; Electrical Impedance Tomography; cardiac surgery