Optimal Positive End-expiratory Pressure (PEEP) in Prone Position During Spine Surgery

Study Overview
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Brief Summary
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Background: There is a lack of studies regarding Optimal (best) positive end-expiratory pressure (PEEP) in prone position during surgery, and its relation with optimal PEEP in supine position. Hypothesis: In patients undergoing scheduled spinal surgery, optimal PEEP in the prone position is lower than optimal PEEP in the supine position. Aims: To assess the difference optimal PEEP in supine vs. prone positions in patients undergoing spine surgery. To evaluate the changes in optimal PEEP in prone position throughout the surgical procedure. Methods: Observational study, one center. Main variable: optimal PEEP. Secondary variables: PaO2, pCO2 and dynamic compliance (Crd) in prone and supine position.

Detailed Description
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Recruitment: Patients scheduled for spine surgery were Main outcome: Optimal PEEP determined after a pulmonary recruitment manoeuvre in supine and in prone position and every hour during the surgery in prone position. Secondary outcomes: Pulmonary compliance, blood gas analysis and hemodynamic parameters

Official Title
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Optimal Positive End-expiratory Pressure (PEEP) in Prone Position During Spine Surgery. A Prospective Observational Study

Conditions
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Anesthesia, Surgery

Intervention / Treatment
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* Other: Evaluation of PEEP in prone position


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥18 years. Spine prone surgery lasting ≥2 hours. Absence of known pulmonary pathology. Exclusion Criteria: Pregnancy or lactation. Contraindication to alveolar recruitment maneuvers (risk of barotrauma, hemodynamic instability). Body mass index (BMI) >35. Heart failure defined as IC <2.5 L/min/m2 and/or inotropic support requirements prior to surgery. Diagnosis or suspicion of intracranial hypertension (intracranial pressure >15 mmHg).

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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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Evaluation of PEEP in prone position|Assessment of optimal Positive End-Expiratory Pressure (PEEP) in patients undergoing scheduled spine surgery in prone position.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Positive End-Expiratory Pressure (PEEP) | Positive End-Expiratory Pressure (cmH2O) in supine position | 10 minutes after intubation | 
| Positive End-Expiratory Pressure (PEEP) | Positive End-Expiratory Pressure (cmH2O) in prone position | 10 minutes after positioning | 
| Change in Positive End-Expiratory Pressure (PEEP) | Variation of Positive End-Expiratory Pressure (cmH2O) during surgery in prone position with respect to PEEP value at 10 minutes after positioning | From determination of optimal PEEP until the first hour and then every hour, assessed up to the end of surgery (maximum 6 hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Static compliance | Tidal volume / Plateau pressure ratio (mL/cmH2O) in supine position | 10 minutes after intubation | 
| Static compliance | Tidal volume / Plateau pressure ratio (mL/cmH2O) in prone position | 10 minutes after positioning | 
| Change in static compliance | Variation of static compliance (Tidal volume / Plateau pressure ratio, in mL/cmH2O) during surgery in prone position | Measured at the same time as Auto PEEP until the first hour and then every hour, assessed up to the end of surgery (maximum 6 hours) | 
| Arterial oxygen pressure (PaO2) | Partial pressure of oxygen (mmHg) in supine position | 10 minutes after intubation | 
| Arterial oxygen pressure (PaO2) | Partial pressure of oxygen (mmHg) in prone position | 10 minutes after positioning | 
| Change in arterial oxygen pressure (PaO2) | Variation of partial pressure of oxygen (mmHg) during surgery in prone position | Measured at the same time as Auto PEEP until the first hour and then every hour, assessed up to the end of surgery (maximum 6 hours) | 
| Arterial carbon dioxide pressure (PaCO2) | Partial pressure of carbon dioxide (mmHg) in supine position | 10 minutes after intubation | 
| Arterial carbon dioxide pressure (PaCO2) | Partial pressure of carbon dioxide (mmHg) in prone position | 10 minutes after positioning | 
| Change in arterial carbon dioxide pressure (PaCO2) | Variation of partial pressure of carbon dioxide (mmHg) during surgery in prone position | Measured at the same time as Auto PEEP until the first hour and then every hour, assessed up to the end of surgery (maximum 6 hours) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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prone position, anesthesia, general, end-expiratory pressure, positive, respiration, artificial