A Non-invasive Evaluation of Kidney-Lung Interactions

Study Overview
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Brief Summary
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The present study aims to evaluate, with non-invasive methods, the relationships existing between PEEP and renal perfusion in patients undergoing surgery and requiring ventilatory support and monitoring in intensive care. Renal perfusion will be assessed at baseline (PEEP 0), subsequently ,at the application of progressive increases of PEEP. At the end of the measurements, the implications of the use of PEEP on the renal vascular system will be analyzed.

Detailed Description
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The present physiological, monocentric, observational clinical study evaluates the effect of progressive PEEP increases on renal perfusion in mechanically ventilated patients who underwent surgery with the need of ventilatory support and monitoring in intensive care. Precisely, will be evaluated: The morphometric parameters (coronal diameter and cortico-medullary thickness) and the renal resistive indices (IR). The inter-lobar arteries will be sampled and the IRs will be measured as the upper and lower level and the mesorenes. Measurements will be performed both in the kidney and in baseline conditions and incremental values of PEEP (0 - 6 - 12). Gas exchanges, FC, systolic BP, diastolic and mean, Pmax, P1 and P2 of the airways, total and ohmic resistances and static respiratory compliance indexed for weight body (RRSmaxI, RRSminI, CrsI will be recorded). The intra-class correlation coefficient will be measured to estimate the intra-observer reproducibility of the conducted measurement.

Official Title
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KIDNEY - LUNG INTERACTION: the Effect of End-expiratory Pressure on Renal Perfusion. Non-invasive Evaluation.

Conditions
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Perfusion; Complications, Mechanical Ventilation Complication

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 Years and older Receiving mechanical ventilation, invasive blood pressure monitoring and an urinary catheter to monitor diuresis Need for postoperative monitoring in intensive care Written informed consent; Exclusion Criteria: Acute kidney injury defined according to KDIGO guidelines; Pre-existing chronic renal disease; Heart failure; ARDS; Sepsis and Septic Shock; Hemodynamic instability with the need for vasoactive support; Chronic or occasional therapy with drugs that could modify the renal blood flow and that can not be suspended two days before the study (Vasoactive agents, Ace-inhibitors, Beta-blockers, NSAIDs, Sartans and Diuretics therapy); Presumed or established state of pregnancy; Refusal of informed consent;

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

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Resistive Index and Peep Titration<br>Enrolled patients will receive a sequential, step-wise increase in PEEP from 0 cmH2O to 12 cmH2O. The inter-lobar arterioles will be sampled at each PEEP increment and the IR will be measured as the average of three values recorded at the upper and lower pole and at the mesorenes in each kidney. Gas exchanges, HR, systolic, diastolic and mean PA, Pmax, P1 and P2 airway, total resistance and ohmic resistance and static respiratory compliance indexed for body weight (RRSmaxI, RRSminI, CrsI) will be measured at each Peep Level. The physiologic measurements will be obtained at regular intervals (within 15 minutes at each PEEP level) throughout the PEEP titration period. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association between IR and PEEP | Resistive index will be measured in both kidney and recorded using multifrequency convex probe.The association between positive end expiratory pressure and resistive index will be analyzed as the primary outcome. | Change from baseline to 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Association between PEEP and Hemodynamics Paramenters | Resistive index will be measured in both kidney and recorded using multifrequency convex. FC, systolic, diastolic and mean PA will be measured at each PEEP level | Change from baseline to 60 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Renal blood perfusion, Mechanical ventilation