Prone Position and Renal Resistive Index

Study Overview
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Brief Summary
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Patients suffering from Acute Respiratory Distress Syndrome (ARDS) with a prone position (PP) indication will benefit from measurements of radiological and biological kidney injury markers, intra-abdominal pressure (IAP) and ventilatory mechanics in supine position (baseline IAP), after 2 hours in PP at the current IAP value, thirty minutes after patients' abdomen suspension in order to resume baseline IAP and after patients' are turned back to supine position.

Official Title
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Effect of Prone Position on Renal Resistive Index Among Patients With Acute Respiratory Distress Syndrome. The Role of Intra-abdominal Pressure

Conditions
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Acute Respiratory Distress Syndrome, Acute Kidney Injury, Prone Position, Intra-Abdominal Hypertension

Intervention / Treatment
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* Other: Prone position


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ARDS patients according to Berlin criteria, intubated, mechanically ventilated since at least 24 hours, with PaO₂/FiO₂ < 150 mmHg, neuromuscular blockade with an indication of PP done by the physician in charge possibility to differ PP for one hour patients should be hemodynamically stable since at least 4 hours Exclusion Criteria: Pregnant or breast-feeding women legal protection, no social security affiliation PP contra-indication nasogastric tube contra-indication extra corporeal membrane oxygenation acute kidney injury at inclusion according to K-DIO criteria, chronic kidney disease defined as an estimated glomerualr filtration rate less than 30 ml/min/1.73m², kidney transplantation, renal artery stenosis, solitary kidney, albuminuria > 1.25 mg/ml cardiac arrhythmia obesity advanced cirrhosis

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: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Prone position<br> | Other: Prone position<br>* Abdomen suspension in prone position<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in renal resistive index (RRI) | RRI measurement will be performed on a right kidney arcuate/interlobar artery, with a high frequency Doppler probe. Three to five consecutive measures will be obtained then RRI computed according to the formula: (peak systolic velocity - end diastolic velocity)/peak systolic velocity). | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| change in renal medullary oxygen tension | urinary oxygen tension (uPO₂) will be measured via a fiber-optic luminescence optode inserted through the bladder catheter lumen | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 
| change in cell-cycle arrest biomarkers | Tissue inhibitor of metalloproteinases 2 and Insulin-like growth factor-binding protein 7 concentrations product ([TIMP2] · [IGFBP7]) will be measured with a sandwich immunoassay technique | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 
| ventilatory mechanics: transpulmonary pressure | transpulmonary pressure will be measured at the end of inspiration and expiration and continuously recorded on a datalogger | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 
| ventilatory mechanics: driving pressure | driving pressure will be measured at the end of inspiration and expiration and continuously recorded on a datalogger | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 
| ventilatory mechanics: elastance | elastance will be measured at the end of inspiration and expiration and continuously recorded on a datalogger | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 
| haematosis | arterial oxygen tension (PaO2) and arterial dioxide carbon tension (PaC02) | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver | 
| Intra abdominal pressure | Intra abdominal pressure will be measured thanks to a dedicated nasogastric tube with two balloons (gastric pressure) | At inclusion (in supine position), two hours after prone positioning, 30-minutes after the abdomen suspension maneuver and two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on renal resistive index | RRI measurement will be performed on a right kidney arcuate/interlobar artery, with a high frequency Doppler probe. Three to five consecutive measures will be obtained then RRI computed according to the formula: (peak systolic velocity - end diastolic velocity)/peak systolic velocity). | Two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on urinary PO2 | urinary oxygen tension (uPO₂) will be measured via a fiber-optic luminescence optode inserted through the bladder catheter lumen | Two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on cell-cycle arrest biomarkers | Tissue inhibitor of metalloproteinases 2 and Insulin-like growth factor-binding protein 7 concentrations product ([TIMP2] · [IGFBP7]) will be measured with a sandwich immunoassay technique | Two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on ventilatory mechanics: transpulmonary pressure | transpulmonary pressure will be measured at the end of inspiration and expiration and continuously recorded on a datalogger | Two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on ventilatory mechanics: driving pressure | driving pressure will be measured at the end of inspiration and expiration and continuously recorded on a datalogger | Two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on ventilatory mechanics: elastance | elastance will be measured at the end of inspiration and expiration and continuously recorded on a datalogger | Two hours after patients are back in supine position | 
| Persisting effect of IAP increase in prone position when patients are back in supine position on haematosis | arterial oxygen tension (PaO2) and arterial dioxide carbon tension (PaC02) | Two hours after patients are back in supine position | 
| Acute kidney injury | According to creatinine or diuresis criteria of Kidney Disease: Improving Global Outcomes (K-DIGO) classification | within 48 hours following prone position |