The effect of urinary and arterial blood pH on the progression of acute kidney injury in critically ill patients with systemic inflammatory response syndrome or sepsis and oliguria.

PURPOSE: The aim of this study was to examine the relationship between urinary and arterial blood pH and the progression of acute kidney injury in critically ill patients with sepsis or SIRS and oliguria.

DESIGN AND SETTING: A prospective observational study was performed on critically ill adults in a tertiary intensive care unit in Melbourne, Australia. Urinary and arterial blood pH were measured at 12 hourly intervals for 60h for patients with sepsis or SIRS, oliguria and who were at high risk of acute kidney injury. Patient RIFLE class at baseline and 60h were assessed for an association to urinary and arterial blood pH. Secondarily, change in peak serum creatinine from baseline over 5 days was assessed for an association to mean urinary and arterial blood pH in the first 48h of the study. Finally, relevant patient demographic and physiological variables were assessed for an association to change in peak serum creatinine from baseline over 5 days.

RESULTS: 44 patients were included in the study; 13 did not survive to hospital discharge. Baseline arterial blood pH was associated with baseline RIFLE class but not RIFLE class at 60h. Urinary pH was not associated with RIFLE class at baseline or 60h. There was no association between mean urinary or arterial blood pH in the first 48h and change in peak serum creatinine from baseline over 5 days. None of the patient and demographic and physiological variables showed an association to change in peak serum creatinine from baseline in the 5-day study period.

CONCLUSION: Urinary and arterial blood pH were not associated with the progression of acute kidney injury in critically ill patients with sepsis or SIRS and at risk of acute kidney injury.