Back
Acute kidney injury (AKI), one of the most dreadful disease with a broad etiological profile, a challenging problem, specially in critically ill patients and also associated with high morbidity and mortality. Measurement of Renal indices are commonly used to differentiate prerenal AKI from ATN, often cannot be used, and also may not be accurate in many conditions. As Renal biopsy is gold standard but this invasive procedure may not be feasible in critically ill patients. Accurate and rapid diagnosis of the cause of AKI is particularly important for selecting appropriate therapy. Therefore, this study was conducted to assess the ability of Resistive index (RI) from Doppler USG to differentiate prerenal AKI and ATN
This cross sectional study, conducted at Dhaka Medical College Hospital,Bangladesh.Total 80 AKI patients aged > 18 years with previous normal renal function were included. Patients with CKD, post renal cause of AKI, Chronic disease that may affect the RI e.g. DM, known hypertensive patients, Lupus nephritis, renal allograft recipients and Patients with known renal artery stenosis were excluded from study. The diagnosis of ATN or prerenal AKI was made on the basis of history, clinical features and laboratory parameters (Renal indices, FENa, RFI, Creatinine ration). Doppler Ultasound was performed within 24 hours of admission. The Mean RI for each patient was considered as an average of both kidneys.
Among 80 patients, majority 31% of patients were 31-40 years and 65% were male. Among all, 19% of AKI patients presented with sepsis, followed by acute watery diarrhoea 17%, drug induced 13.8%,vomiting 10%,cardiorenal failure 10%, rhabdomyolysis 7.5%, hyperbilirubinaemia 6.%, multiple myeloma 5%, paraquat poisoning3.38%, massive haemorrhage 3.8%, AKI after bee sting bite 2.5% and DIC 1.3%. (figure 1). Decreased urine output57.% was the most common presenting complaint followed by hypotension 7.5% and 23.8% with hypertension. In this study AKI was classified based on, clinical information, value of renal indices and RI value. According to RI 45% patients had prerenal AKI(RI<0.70) with mean RI 0.63±0.07 and 55% patients had ATN (RI >0.70) with mean RI 0.77±0.71(Table 1).Whereas, according to renal indices 47% patients had prerenal AKI and 53% ATN. But, type of AKI based on clinical diagnosis was considered as standard, where 46% of the AKI patients were prerenal AKI and 54% ATN . when type of AKI based on renal indices FENa and RFI were very high in ATN group and creatinine ratio was higher in prerenal group (Table II).when type of AKI based on RI values, FENa and RFI were very also high in ATN group and creatinine ratio was higher in prerenal group.( Table III). In this study clinical information was compared with both RI (Table IV) values and renal indices (Table V) and found RI to be more correlated (P<0.001).We found RI has sensitivity 91.89% and specificity 95.35% in the differentiation of prerenal AKI and ATN (table VI) and renal indices had low sensitivity (62.16%) and specificity (65.12%).
In this study, it has found that RI is superior with high sensitivity and specificity than renal indices and can be used as an usefull tool in differentiation between prerenal AKI and ATN to achieve a great outcome regarding patient management, avoid AKI related complications