Abstract
BackgroundThe optimal mean arterial pressure (MAP) in cases of septic shock is still a matter of debate in patients with prior hypertension. An MAP between 75 and 85 mmHg can improve glomerular filtration rate (GFR) but its effect on tubular function is unknown. We assessed the effects of high MAP level on glomerular and tubular renal function in two intensive care units of a teaching hospital. Inclusion criteria were patients with a history of chronic hypertension and developing AKI in the first 24 h of septic shock. Data were collected during two 6 h periods of MAP regimen administered consecutively after haemodynamic stabilisation in an order depending on the patient's admission unit: a high-target period (80–85 mmHg) and a low-target period (65–70 mmHg). The primary endpoint was the creatinine clearance (CrCl) calculated from urine and serum samples at the end of each MAP period by the UV/P formula.Results26 patients were included. Higher urine output (+0.2 (95%:0, 0.4) mL/kg/h; P = 0.04), urine sodium (+6 (95% CI 0.2, 13) mmol/L; P = 0.04) and lower serum creatinine (− 10 (95% CI − 17, − 3) µmol/L; P = 0.03) were observed during the high-MAP period as compared to the low-MAP period, resulting in a higher CrCl (+25 (95% CI 11, 39) mL/mn; P = 0.002). The urine creatinine, urine–plasma creatinine ratio, urine osmolality, fractional excretion of sodium and urea showed no significant variation. The KDIGO stage at inclusion only interacted with serum creatinine variation and low level of sodium excretion at inclusion did not interact with these results.ConclusionsIn the early stage of sepsis-associated AKI, a high-MAP target in patients with a history of hypertension was associated with a higher CrCl, but did not affect the kidneys' ability to concentrate urine, which may reflect no effect on tubular function.
Highlights
The optimal mean arterial pressure (MAP) in cases of septic shock is still a matter of debate in patients with prior hypertension
Age ≤ 18 years, obstructive renal disease, Acute kidney injury (AKI) from an obstructive or suspected cause other than sepsis, severe chronic kidney disease defined based on a known Estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2, renal replacement therapy (RRT) or anuria at the time of inclusion, and a presumed life expectancy < 24 h
AKI was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) classification on the criteria of urine output (UO) and serum creatinine [8]
Summary
The optimal mean arterial pressure (MAP) in cases of septic shock is still a matter of debate in patients with prior hypertension. We assessed the effects of high MAP level on glomerular and tubular renal function in two intensive care units of a teaching hospital. In patients with septic shock, the Surviving Sepsis Campaign guidelines recommend an initial target MAP of 65 mmHg. It is highlighted that when a better understanding of any patient’s condition is obtained, the MAP target should be individualized to the pertaining circumstances as it may be too low for certain patients [3]. European expert recommendations suggest higher MAP target in septic shock patients with history of hypertension and in patients that show clinical improvement with higher blood pressure [4]
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