Interest of Urinary Oxygen Partial Pressure (PO2u) in Predicting the Onset or Recovery of Acute Renal Failure During Shock States - OXYpi Study

Shock state is defined as an acute, life-threatening, circulatory failure with impaired tissue oxygenation (or tissue hypoxia). The cause of the shock state can be septic, anaphylactic, hypovolemic or cardiogenic. Its management is based on etiological treatment and replacement of organ failures. Acute kidney injury (AKI) may be lead by renal hypoxia. Acute kidney injury is frequent in patients admitted to intensive care unit (ICU) and associated with an increased mortality. Serum creatinine is the reference biological marker in the diagnosis of Acute kidney injury. However, its use is limited by a delayed increase in plasma creatinine level in relation to the causal renal agression, at a time when renal tissue damage may already be established. Thus, the identification of a biological marker making it possible to estimate renal hypoxia continuously during a shock could allow us to identify early a situation at risk of evolving into Acute kidney injury.

The renal medulla is vulnerable to tissue hypoxia with a risk of acute tubular necrosis. As in situ measurement of mPO2 is not possible in current practice in humans, several studies have shown a positive correlation between variations in mPO2/uPO2 and occurence of Acute kidney injury. In humans, studies have shown a significant association between the reduction in uPO2 in cardiac surgeries and the occurrence of postoperative Acute kidney injury. The aim of the study is to describe the association between uPO2 values and the onset of Acute kidney injury and/or the ocurrence of early recovery of renal function after Acute kidney injury. Any patient in shock (group A) or without shock and requiring urinary catheterization as part of treatment (group B) admitted to the Medical-Intensive Care Unit of Angers University Hospital is eligible for inclusion. After inclusion, a continuous uPO2 measuring probe is introduced with the placement of the urinary probe. uPO2 is collected continuously for the first 5 days of admission or until discharge from intensive care or removal of the urinary catheter. uPO2 is also measured by a gasometry on a urine sample on a multi-daily basis. Serum creatinine is collected every 12 hours (twice a day) and diuresis every two hours for 5 days.


Eligibility Criteria:
Inclusion Criteria :

Group A:

- Patient admitted to Intensive Care Unit with a shock state defined by arterial hypotension requiring vascular filling and/or introduction of catecholamines - Age ≥ 18 years - Affiliated or benificiary of a social security scheme - Consent of the patient or a relative, or inclusion as part of an emergency inclusion procedure

Group B:

* Patient admitted to Intensive Care Unit without shock
* Requiring urinary catheterization as part of routine care
* Age ≥ 18 years
* Affiliated or benificiary of a social security scheme
* Consent of the patient or a relative, or inclusion as part of an emergency inclusion procedure

Exclusion Criteria:

- Preexisting chronic kidney disease (CKD) (GFR \< 60 mL/min/1,73 m2 according to MDRD) - Chronic dialysis and/or kidney transplant - Anuria - Indication for renal replacement therapy (life-threatening hyperkaliemia, severe metabolic acidosis pH \< 7,15, uremia \> 40 mmol/L, pulmonary edema resistant to diuretics) - Patient requiring an extracorporeal life support (ECLS) - Pregnant, breastfeeding or parturient woman - Patient deprived of liberty by judicial or administrative decision - Patient under psychiatric care - Patient under legal protection measures