The Effect of Pressure-controlled Ventilation-volume Guaranteed Mode

Study Overview
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Brief Summary
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The anesthetized patient is turned to the prone position during lumbar spine surgery. The dynamic compliance of lung usually decreases and peak airway pressure increases during the surgery. A new ventilation mode, pressure-controlled ventilation with volume guaranteed mode (PCV-VG) has been recently introduced. The ventilator compares the tidal volume of the previous breath and automatically regulates the pressure up or down to achieve the set tidal volume. This prospective, randomized study is designed to compare the effect of PCV-VG and volume-controlled ventilation (VCV) on peak airway pressure, lung compliance and hemodynamic variables.

Detailed Description
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Total 34 patients with American Society of Anesthesiologists physical status I-III who underwent lumbar spine surgery in prone position were enrolled. All patients fasted for 8 hours before the surgery and were premedicated with intramuscular glycopyrrolate 0.2 mg. Anesthesia was induced with remifentanil (0.1-0.2 ug/kg/min), propofol (1.5-2 mg/kg) and rocuronium (0.6 mg.kg) and maintained with sevoflurane (2.0-2.5 vol%) in inspired oxygen fraction with 0.5, remifentanil (0.05-0.3 ug/kg/min) and vecuronium (0.03-0.05 mg/kg/hr). A 20 G catheter was inserted into the radial artery to monitor continuous arterial pressure and hemodynamic variables (cardiac output, cardiac index, stroke volume, stroke volume index, and stroke volume variation) monitoring. All patients were ventilated with a Datex-Ohmeda Ventilator (S/5 AVANCE). Patients were randomized to receive either PCV-VG (n=17) or VCV (n=17) mode. The tidal volume in both group were set to deliver 8 mL/kg of ideal body weight. The respiratory rate (RR) was adjust to maintain end tidal CO2 (ETCO2) 33-38 mmHg. Hemodynamic variables (mean blood pressure, heart rate, cardiac output, cardiac index, stroke volume, stroke volume index, and stroke volume variation) , respiratory variables (saturation, RR, ETCO2, peak airway pressure, mean airway pressure and lung dynamic compliance) and arterial gas analyses were recorded at 4 stages: (1) 15 minutes after induction in supine position, (2) 30 minutes after turning the patient to the prone position, (3) 60 minutes after turning the patient to the prone position, (4) 15 minutes after turning the patient to supine position at the end of surgery.

Official Title
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Comparison of Pressure-controlled Ventilation-volume Guaranteed Mode With Volume Controlled Ventilation in Prone Position During Lumbar Spine Surgery.

Conditions
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Anesthesia

Intervention / Treatment
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* Device: Group PCV-VG
* Device: Group VCV


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who were scheduled for lumbar spine surgery with the prone position American Society of Anesthesiologists physical status I-III Exclusion Criteria: Age under 20 years old or over 70 years old Body mass index > 30 kg/m2 Systolic blood pressure < 100 mmHg Heart rate < 60 bpm Uncompensated cardiac disease FEV1 < 60% Hypoxemia (PaO2 < 60 mmHg or oxygen saturation < 90%)

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

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group PCV-VG<br>Pressure controlled ventilation-volume guaranteed | Device: Group PCV-VG<br>* Pressure controlled ventilation-volume guaranteed<br>|
| Active Comparator: Group VCV<br>Volume controlled ventilation | Device: Group VCV<br>* Volume controlled ventilation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak airway pressure | The highest level of pressure applied to the lungs during inhalation | About 2-3 hours through the surgery |