Individualized PEEP in Thoracic Surgery

Study Overview
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Brief Summary
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Intraoperative protective ventilation with low tidal volumes (TV), positive end-expiratory pressure (PEEP) and possibly lung recruitment maneuvers (RMs) reduces postoperative pulmonary complications. In thoracic surgery, in one-lung ventilation (OLV), the evidence is lacking. However, in this context protective ventilation with PEEP titration is related to better intraoperative oxygenation and respiratory mechanics. It is not clear whether this strategy is associated also with better postoperative oxygenation and less postoperative pulmonary complications.

Detailed Description
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In this randomized controlled trial the investigators will enroll 42 patients scheduled for elective thoracic surgery (minithoracotomic or video-assisted thoracoscopic segmentectomies and lobectomies). Patients will be randomized in two groups: BEST PEEP and STANDARD PEEP. In OLV the investigator will set a TV = 5ml/kg IBW in volume control ventilation (VCV) and an adequate respiratory rate (RR) to keep PaCO2 < 60 mmHg. With the patient in lateral decubitus and open chest, a cycling step RM (in pressure control ventilation, RR =10/min, I:E=1:1, up to Paw = 40 cmH20 with a PEEP = 20 cmH2O, lasting 2.5 minutes) and a PEEP decremental titration trial (in VCV, from 16 to 4 cmH2O) will be performed to all patients. Then, after another RM, in STANDARD PEEP group a PEEP of 5 cmH2O will be set, and in BEST PEEP group an individualized PEEP (the one corresponding to the lower driving pressure, +2 cmH2O) will be applied till the end of surgery. A blood gas analysis will be performed before surgery, with the patient in supine position breathing room air (T1). The respiratory mechanics (Ppeak, Pplateau, PEEP, driving pressure) and blood gas (PaO2, PaCO2, pH, HCO3, lactates) parameters will be then collected at the following time points: T2 - 5 minutes after induction, patient supine, two lung ventilation; T3 - lateral decubitus, chest open, OLV, before RM; T4 - 10 minutes after second RM; T5, 6, 7 - every hour after T4; T8 - at the end of OLV, before lung re-expansion; T9 - patient supine, two lung ventilation, before neuromuscular block reversal. Postoperatively all patients will spend at least one hour in a Recovery Room, in oxygen-therapy through a Venturi mask with FiO2 = 60%. A blood gas analysis and data about pain (NRS scale 0-10) and sedation (Ramsey score) will be collected at 1 hour postoperatively (T10). The primary outcome of the study is intra- and postoperative oxygenation and secondary outcomes are intraoperative respiratory mechanics parameters.

Official Title
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Individualized vs Standard PEEP in Thoracic Surgery: Effects on Respiratory Mechanics and Intra- and Postoperative Oxygenation

Conditions
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Thoracic Surgery, One-lung Ventilation, Respiratory Mechanics, Artificial Respiration

Intervention / Treatment
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* Procedure: Best PEEP
* Procedure: Standard PEEP


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Patient's consent to the trial Candidate to elective lung lobectomy or segmentectomy (minimally invasive thoracotomy or video-assisted thoracoscopy) ASA class 1-3 BMI < 30 kg/m2 Exclusion criteria: Pregnancy Previous pneumothorax, Emphysematous bullae Severe COPD METs < 4 due to cardiac disease

Ages Eligible for Study
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Minimum Age: 18 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: BEST PEEP<br>During OLV an individualized PEEP will be applied i.e. the one corresponding to the lower driving pressure, + 2 cmH2O | Procedure: Best PEEP<br>* In OLV, the investigator will perform a PEEP decremental titration trial, decreasing PEEP from 16 to 4 cmH2O (steps of 2-cmH2O, lasting 1 minute). At the end of every step driving pressure (Pplat-PEEP) will be calculated, and the PEEP corresponding to the lowest driving pressure + 2cmH2O will be set.<br>|
| Active Comparator: STANDARD PEEP<br>During OLV a PEEP of 5 cmH2O will be applied | Procedure: Standard PEEP<br>* In OLV, a PEEP of 5 cm H2O will be set.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of oxygenation | Oxygen arterial partial pressure/fraction of inspired oxygen (PaO2/FiO2) | The blood gas analysis will be performed at the time points from T1 to T10 (preoperative, during surgery and 1 hour postoperative). The investigators will perform intra- and inter-group comparisons. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of driving pressure | Driving pressure = Pplateau -PEEP | The respiratory mechanics parameters will be collected at the time points from T2 to T9 (during surgery). The investigators will perform intra- and inter-group comparisons. | 
| Change of plateau pressure | Airway pressure during an end-inspiratory pause | The respiratory mechanics parameters will be collected at the time points from T2 to T9 (during surgery). The investigators will perform intra- and inter-group comparisons. | 
| Change of static respiratory system compliance | Cstat = TV/(Pplat-PEEP) | The respiratory mechanics parameters will be collected at the time points from T2 to T9 (during surgery). The investigators will perform intra- and inter-group comparisons. | 
| Change of respiratory rate | Respiratory rate set on the ventilator | The parameter will be collected at the time points from T2 to T9 (during surgery). The investigators will perform intra- and inter-group comparisons. | 
| Change of carbon dioxide | Carbon dioxide arterial partial pressure | The blood gas analysis will be performed at the time points from T1 to T10 (preoperative, during surgery and 1 hour postoperative). The investigators will perform intra- and inter-group comparisons. | 
| Change of end expiratory carbon dioxide partial pressure | Carbon dioxide end-expiratory partial pressure | The respiratory parameters will be collected at the time points from T2 to T9 (during surgery). The investigators will perform intra- and inter-group comparisons. | 
| Change of pH | Arterial pH | The blood gas analysis will be performed at the time points from T1 to T10 (preoperative, during surgery and 1 hour postoperative). The investigators will perform intra- and inter-group comparisons. | 
| Lactate | Arterial lactate | The blood gas analysis will be performed at the time points from T1 to T10 (preoperative, during surgery and 1 hour postoperative). The investigators will perform intra- and inter-group comparisons. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Individualized PEEP, One-lung ventilation, Oxygenation