Comparison of the effect of two Pressure and Volume control ventilation during one lung ventilation in thoracic surgeries on the gas exchanges and the respiratory mechanical variables

Comparision of the effect of two Pressure and Volume control ventilation during one lung ventilation in thorasic surgeries

This study is a one-sided blind clinical trial, with parallel, randomized groups on 60 patients. For randomization, we use the block randomization method.

In both groups, after induction of anesthesia, the patient is intubated with a left round double lumen endotracheal tube. Then we take an arterial line from the radial artery. With the start of surgery, one-lung ventilation begins for patients with the following characteristics. In the pressure control ventilation group, mechanical ventilation begins with an airway pressure of 20 cm of water, a rate of respiration of 12 per minute. Gradual changes in airway pressure are used to achieve an ideal tidal volume of 6 ml / kg. In the volume control ventilation group, a tidal volume of 6 ml / kg and a respiration rate of 12 beats per minute are used to ventilate the patient. In both groups, we use a change in respiration rate to achieve adequate minute ventilation. Finally, the variables are measured and recorded.

Inclusion criteria: ASA physical class < or = class III Patients with a body mass index between 20 and 35, Have grade 1 and 2 Mallampati on airway examination Exclusion criteria: Severe hypoxemia

Intervention group: Patients who are candidates for chest surgery, after anesthesia, their ventilation is performed with ventilator pressure control mode. Control group: Patients who are candidates for chest surgery, after anesthesia, their ventilation is performed with ventilator volume control mode.

Arterial blood oxygen pressure, peak airway pressure, dynamic lung compliance, end-tidal Co2, respiratory dead space

This is a randomized clinical trial in which patients are assigned to one of two study groups using simple randomization methods in order of their entry. The randomization unit is personal and using a lottery drawing method, the third person draws blindly a sealed paper on which one of two groups' name is written. Thus we could achieve a concealed random sequence for allocation of patients as the process of lottery is repeated for each new patient entered.

Due to this fact that the study is performed under general anesthesia, the participating patients do not know the group and type of intervention. There is no possibility for blinding the person who intervenes and records the outcomes.