Transpulmonary Driving Pressure and Intra-abdominal Pressure Relationship During Laparoscopic Surgery

Study Overview
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Brief Summary
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Objective: The aim of this project is to evaluate how intra-abdominal pressure paired coupled with different ventilatory positive end-expiratory pressure levels affects the transpulmonary driving pressure during pneumoperiteneum insufflation for laparoscopic surgery. Methodology: Patients undergoing laparoscopic surgery will be included. The study will investigate the relationship between intra-abdominal pressure (IAP) and transpulmonary driving pressure (TpDp) and the effect of titration of PEEP on their relationship. At three different levels of intra-abdominal pressure, the respiratory driving pressure (RDp) and TpDp in each subject will be measured in each subject. The same subject will undergo two different ventilation strategies. Demographic data (height, weight, body mass index and sex), ASA physical status (surgical risk classification of the American Society of Anesthesiology), number of previous abdominal surgeries, number of previous pregnancies, and respiratory comorbidities will be collected. Respiratory pressures and mechanics will be recorded at each level of intra-abdominal pressure (IAP) during each ventilatory strategy. The variables recorded will include: airway pressures (Plateau pressure Pplat, Peak pressure, Ppeak), the final esophageal pressure of inspiration and expiration and pulmonary stress index. Mixed linear regression will be used to evaluate the relationship between different PEEP levels, IAP and TpDp by adjusting for known confounders and adding individuals as a random factor. Likewise, an analysis using a mixed linear regression model with the pulmonary stress index as a function of the intra-abdominal pressure, the ventilation regime, and a specific random intercept term for each subject will be performed.

Official Title
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Assessment of Transpulmonary Driving Pressure and Intra-abdominal Pressure Relationship at Different Levels of Positive End-expiratory Pressure (PEEP) During Laparoscopic Surgery

Conditions
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Anesthesia, General/Methods, Laparoscopy, Respiration, Artificial, Positive-Pressure Respiration, End-Expiratory Pressure, Positive, Ventilator-Induced Lung Injury

Intervention / Treatment
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* Other: Standard PEEP ventilation
* Other: Matched PEEP ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiology (ASA) risk scale I to III Age > 18 years Previously signed informed consent Undergoing laparoscopic surgery Exclusion Criteria: ASA ≥ IV Pregnancy Advanced liver, kidney or cardiopulmonary 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: Diagnostic
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Standard PEEP ventilation<br>During pneumoeperitoneum insufflation the patient is ventilated with 7 ml/kg per ideal body weight, inspiration:expiration (I:E) ratio 1:2, and respiration rate (RR) to maintain EtCO2 at 35-38 mmHg and 5 cmH20 of PEEP at every intra-abdominal pressure (IAP) step (8, 12 and 15 mmHg). | Other: Standard PEEP ventilation<br>* During mechanical ventilation a fixed PEEP (5 mcH2O) is set at all IAP levels during pneumoperitoneum insufflation<br>Other: Matched PEEP ventilation<br>* During mechanical ventilation PEEP is matched to IAP level<br>|
| Experimental: Matched PEEP Ventilation<br>During pneumoeperitoneum insufflation the patient is ventilated with 7 ml/kg per ideal body weight, inspiration:expiration (I:E) ratio 1:2, and respiration rate (RR) to maintain EtCO2 at 35-38 mmHg and a level of PEEP matched to every IAP step (8, 12 and 15 mmHg). 1 mmHg = 1,36 cmH20. Between the standard and matched PEEP intervention there is a washout period that with a recruitment maneuver to re-establish baseline lung condition. | Other: Standard PEEP ventilation<br>* During mechanical ventilation a fixed PEEP (5 mcH2O) is set at all IAP levels during pneumoperitoneum insufflation<br>Other: Matched PEEP ventilation<br>* During mechanical ventilation PEEP is matched to IAP level<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transpulmonary driving pressure (TpDp) difference between standard and matched PEEP ventilation | TpDp (assessed in centimeters of water, cmH20) as assessed by ventilatory pressure and pleural pressure (recorded by an esophageal probe) is recorded at every intra-abdominal pressure level during pneumoperitoneum insufflation. The primary outcome is the difference between a standard perioperative management (fixed PEEP + 15 mmHg pneumoperitoneum pressure) and matched PEEP to intra-abdominal pressure and 8mmHg intra-abdominal pressure | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transpulmonary driving pressure and intra-abdmominal pressure relationship (multivariate adaptive linear regression) | TpDp (in cmH20) is recorded at different levels of IAP and with two different PEEP settings (in cmH20; two levels are: fixed at each IAP level, standard group and matched at each IAP level, matched group). The relationship between TpDp and IAP (both treated as continuous variables) at each PEEP level is plotted and a multiadaptive linear regression is fitted. | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 
| Transpulmonary driving pressure and respiratory driving pressure (RDp) relationship (multivariate adaptive linear regression). | Respiratory driving pressure (transpulmonary driving pressure + pressure to move the chest wall, in cmH20, RpDp) and TpDp relationship at each IAP and PEEP level will be assessed. The relationship between TpDp and RpDp (both treated as continuous variables) at each PEEP level is plotted and a multiadaptive linear regression is fitted. | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 
| Respiratory system compliance (Crs) difference between standard and matched PEEP levels | Respiratory system compliance measures the system's ability to stretch. It has two components Lung and Chest Wall (measured in milliliter/centimeters of water, ml/cmH20) | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 
| Pulmonary compliance (Cp) difference | Respiratory system compliance measures the system's ability to stretch (ml/cmH20). It has two components Lung and Chest Wall (measured in milliliter/centimeters of water, ml/cmH20). By using an esophageal probe measurement the two can be partitioned and analyzed separately. | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 
| Chest wall compliance (CCw) difference | Respiratory system compliance measures the system's ability to stretch (ml/cmH20). It has two components Lung and Chest Wall (measured in milliliter/centimeters of water, ml/cmH20). By using an esophageal probe measurement the two can be partitioned and analyzed separately. | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 
| Pulmonary Stress index difference | Stress index is based on respiratory pressure curve analysis and assess whether the lungs are overdistended or collapsed | Pneumoperitoneum insufflation before surgery (up to 30 minutes) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Mechanical ventilation, Driving Pressure, Protective Lung VEntilation