Role of Femoral Vein Pulsatility in the Prediction of Acute Kidney Injury in Patients with Peritonitis and Abdominal Sepsis: Interim Analysis of a Prospective Observational Study

INTRODUCTION: Excess fluid administration increases both right and left atrial pressures, resulting in venous congestion, tissue edema leading to increased rates of acute kidney injury(1). At bedside, in patients with poorly accessible thoracic and abdominal wall examination after sternotomy, thoracotomy, or laparotomy; transthoracic echocardiographic (TTE) and venous excess ultrasound (VEXUS) examinations might be challenging because of suboptimal echogenicity, due to unfavourable anatomy and sometimes, positive pressure ventilation(2). A recent observational study identified that nearly 25% of their patients in their cohort had inadequate renal Doppler scans(3). In these instances, the femoral vein, which is an easily accessible site for venous catheters, is easily available for ultrasound evaluation. A good correlation has also been demonstrated between Femoral Vein Doppler(FVD) and VEXUS to identify venous congestion in patients after a major cardiac surgery(4). Visual assessment of the femoral vein flow could be used to binarily note if the patient has a congestive state or not. We hypothesized that the presence of a pulsatile femoral vein flow could predict the onset of AKI in the subsequent 7 days in patients with complicated intra-abdominal infections and abdominal sepsis. OBJECTIVES: To determine the association between femoral vein pulsatility measured (measured by doppler ultrasonography) within 24 hours of ICU admission and development of acute kidney injury within 7 days, in patients with complicated intra-abdominal infections(cIAI)and abdominal sepsis. METHODS: 30 adult patients, aged 18–65 years diagnosed with cIAI were included after institutional ethics committee approval. Patients with inadequate window for USG, patients in respiratory distress (respiratory rate > 35/min, accessory muscles of respiration in use), patients with liver cirrhosis, portal thrombosis, deep vein thrombosis of lower limb were excluded. FVD was considered suggestive of venous congestion if either of the criteria was fulfilled: i) Pulsatile in nature ii) Retrograde flow velocity of more than 10 cm/s iii) Retrograde flow velocity being more than 1/3rd of antegrade flow velocity (flow reversal). RESULTS: FVD was described as normal, pulsatile, or pulsatile with flow reversal. Pulsatile and pulsatile with flow reversal FVD patterns were considered suggestive of venous congestion. Out of 30 patients included in the interim analysis, 18 patients (60%) developed AKI as defined by KDIGO criteria. AKI stage 1 in 8 patients, AKI stage 2 in 8 patients, AKI stage 3 in 2 patients. FVD patterns consistent with congestion was seen in 12 patients (66.6%) out of 18 patients who developed AKI. Pulsatile FVD was seen in 9 patients, Retrograde flow velocity of more than 10 cm/s in 3 patients, Retrograde flow velocity being more than 1/3rd of antegrade flow velocity (flow reversal) in 2 patients. The presence of a pulsatile femoral vein flow could predict the onset of AKI in the subsequent 7 days in patients with complicated intra-abdominal infections and abdominal sepsis with a sensitivity of 66%, specificity of 83%, Positive predictive value of 85%, and a negative predictive value of 62.5%. CONCLUSION: The presence of a pulsatile femoral vein flow could predict the onset of AKI in the subsequent 7 days in patients with cIAI with a PPV of 85% and NPV of 62.5%.