The Effect of Pressure Controlled Ventilation on the Pulmonary Mechanics in Prone Position Using the Wilson Frame: A Comparison With Volume Controlled Ventilation

Study Overview
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Brief Summary
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Prone position in spinal surgery can increase airway pressure and decrease dynamic lung compliance by a frame used for postural stabilization. Also, it can increase hemodynamic instability such as reduced blood pressure by aggravating cardiac index. Former study shows pressure controlled ventilation on the pulmonary mechanics can improve alveolar use and oxygenation than volume controlled ventilation. The latter one means controlling a patient's breathing completely through tidal volume and set breathing rate. This could be useful for the patients not possible to breath by themselves because it guarantees the perfect breathing. The pressure controlled ventilation is used when there is a possibility to change a patient's environment. The pressure will be maintained steadily, but volume and flux will be changed. That means through the pressure already set, the whole breathing will be maintained from the beginning to end. If a patient's resistance is increased, the volume will be decreased even though the way of blood pressure control is same. However, the tidal volume per minute can be controlled somewhat and barotrauma can be decreased by controlling respiratory rate. Through this study, we are expecting the pressure controlled ventilation in prone position can improve lung mechanics and oxygenation.

Official Title
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The Effect of Pressure Controlled Ventilation on the Pulmonary Mechanics in Prone Position Using the Wilson Frame: A Comparison With Volume Controlled Ventilation

Conditions
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Herniation of Lumbar Vertebral Disc

Intervention / Treatment
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* Procedure: volume control
* Procedure: pressure control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: scheduled for lumbar spine surgery under general anaesthesia Exclusion Criteria: Patients with coronary artery occlusive disease morbid obesity (body mass index ≥ 30 kg/m2) cerebrovascular disease and major obstructive or restrictive pulmonary disease

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 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: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PCV<br>Peak airway pressure were set to deliver a tidal volume of 10 ml/kg of ideal body weight | Procedure: volume control<br>* Volume controlled ventilation of tidal volume 10 ml/kg<br>|
| Active Comparator: VCV<br>After anesthetic induction, anesthesia maching were set to deliver a tidal volume of 10 ml/kg of ideal body weight | Procedure: pressure control<br>* Pressure controlled ventilation for peak airway pressure to deliver tidal volume 10 ml/kg.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| peak airway pressure | Record peak airway pressure on anesthesia mechanical ventilator after anesthesia induction and 30 minutes after prone positioning. | 30 minutes after prone position |