Thoraco-abdominal Volume Variations During Anesthesia Studied by OEP.

Study Overview
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Brief Summary
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The aim of this study is to examine chest wall volume changes monitored by opto-electronic plethysmography during recovery from anesthesia and early postoperative period.

Detailed Description
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This is prospective, randomized clinical trial in subjects undergoing elective surgery requiring general anesthesia. Opto-electronic plethysmography (OEP) has been developed as a non-invasive method for the analysis of chest wall motion, allowing highly accurate measurements of chest wall volume changes of different respiratory compartments in various conditions. The investigators set out to use this technology to study chest wall volume changes during recovery from total intravenous anesthesia (from discontinuing the anesthetic agent till extubation) and early postoperative period. The study protocol compares two different approaches: The group receiving recruitment maneuver (RM) immediately after intubation and positive end expiratory pressure (PEEP) 7 cm H20 until extubation. Inspiratory oxygen concentration 40% during recovery from anesthesia. The group not receiving RM, PEEP 0 cm H2O and inspiratory oxygen concentration 100% during recovery from anesthesia. The volume changes of the chest wall is monitored continuously by OEP, functional residual capacity (FRC) and arterial oxygenation are measured at the defined points in the protocol.

Official Title
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Thoraco-abdominal Volume Variation During Recovery From Total Intravenous Anesthesia Studied by Opto-electronic Plethysmography (OEP).

Conditions
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Mechanical Ventilation

Intervention / Treatment
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* Procedure: lung recruitment maneuver


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age > 18 years ASA classification I-II, scheduled for elective surgery requiring general anesthesia signed informed consent Exclusion Criteria: BMI > 35 co-existing respiratory disease (COPD, asthma ) patient refusal pregnancy deformities of the thorax

Ages Eligible for Study
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Minimum Age: 18 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: open lung<br>The lung recruitment maneuver (RM) immediately after intubation using pressure controlled ventilation, increase in peak inspiratory pressure up to 30 cm H2O during tidal ventilation, respiratory rate 4/min and positive end expiratory pressure (PEEP) 15 cm H20. PEEP 7 cm H2O until extubation. Inspiratory oxygen concentration (FiO2) 40% during recovery from anesthesia. | Procedure: lung recruitment maneuver<br>* RM: peak inspiratory pressure 30 cmH2O, PEEP 15 cm H20 FiO2 0,4 (from end of surgery till extubation)<br>|
| No Intervention: control<br>No recruitment maneuver is performed. PEEP 0 cm H2O. Inspiratory oxygen concentration (FiO2) 100 % during recovery from anesthesia. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Opto-electronic plethysmography (OEP) | Respiratory movements and thoracic and abdominal volume changes is recorded continuously using OEP (OEP system, BTS,Milan, Italy) by analysing the movements of retro-reflective markers using six video cameras connected to an automatic optoelectronic motion analyser. | 1. 5 min after each of these steps: the onset of the mechanical ventilation, the randomization, the end of the surgery 2. continuously during recovery 3. one hour after extubation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional residual capacity (FRC) |  | 5 min after each of these steps: the onset of mechanical ventilation, the randomization, the end of the sergery | 
| Oxygenation (paO2) | Arterial blood gas measurement. | 5 min after each of these steps: the onset of mechanical ventilation, the randomization, the end of the surgery, extubation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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mechanical ventilation, pressure control ventilation, lung recruitment, positive end expiratory pressure, opto-electronic plethysmography, chest wall volume variation, intravenous anesthesia