Bladder urine oxygen partial pressure monitoring: Could it be a tool for early detection of acute kidney injury?

Abstract

Acute kidney injury (AKI) necessitating renal-replacement therapy has been associated with high mortality rates in critically ill patients. Usual methods to study AKI encompass the assessment of serum and urine biomarkers. Hypoxia is a major pathophysiological feature of AKI, which necessitates continuous bedside monitoring of renal tissue oxygenation in intensive care unit (ICU) patients. Research has made continuous bladder urine oxygen pressure (PuO2) monitoring possible in humans. Although the value of bladder PuO2 does not represent an absolute value of medullary tissue oxygen pressure (Po2), bladder PuO2 can be considered a window into the renal medullary oxygenation. Bladder PuO2 can be monitored by using probes with oxygen sensors inserted into the urinary bladder. Additionally, PuO2 can be measured manually by using a blood gas analyzer machine. PuO2 monitoring can be potentially helpful in early diagnosis and/or prevention of AKI and guide therapeutic interventions aimed at improving renal oxygen delivery in those patients.

Cardiac Surgery-Associated Acute Kidney Injury in Children after Cardiopulmonary Bypass

“…Measuring partial oxygen pressure in urine, as an indirect indicator of the oxygen delivery to kidney tissues, also allows for continuous assessments of kidney perfusion by installing a fiberoptic probe into the bladder through a urethral catheter. Urine oxygen pressure can be measured by laboratory methods using a gas analyzer, which is a more accessible, simpler, and relatively cheaper alternative [25].…”

Renal Assessment in Acute Cardiorenal Syndrome

“…Increasing experimental and clinical data indicate that reduced renal oxygenation and mitochondrial dysfunction are significant contributors to AKI development and CKD progression [136,137]. Moreover, the latest studies showed that monitoring urine oxygenation may be a useful predictor for AKI development in septic and cardiac surgery patients [138,139]. Hence, it is imperative to study the pathophysiology behind this phenomenon further, identify biomarkers of renal hypoxia and improve techniques that will allow for accurate assessment of renal oxygenation.…”