Background: AAA surgery patients are at high risk for AKI. Hemodynamic instability, hypovolemia, haemorrhage and reduced cardiac output may play a key role in AKI. SVV predicts volume responsiveness in mechanically ventilated patients; elevated levels of Oxigenation Index (OI) are linked to fluid overload and associate to poor outcome in critical ill patients but little is known about their role in AKI. We aimed to assess if patients with wide changes of SVV or OI at clamping and declamping time of the aorta are associated with high risk of AKI development.
Methods: We enrolled 21 consecutive hypertensive patients undergoing elective AAA surgery with supra-renal clamping. Patients were all on volume-control mechanical ventilation (8 ml/kg) and positive end expiratory pressure of 4 cmH2O. Patients with arrhythmias, spontaneous ventilations, and those extubated before 12h post-operative were excluded. SVV was measured with the FlowTrack/Vigileo (Edwards Lifesciences®) device every 3 minutes during the procedure and for 24h after surgery. OI was calculated as =mean airway pressure/(PaO2/FiO2)x100. Patients received 70ml/kg/h of crystalloids; fluid boluses and transfusions were given if needed. Data were compared with ANOVA.
Results: 9 patients(43%) developed AKI, defined as RIFLE Risk category. SVV and OI were significantly higher at aortic clamping (p<0.0001) and declamping time (p< 0.0001 and p< 0.01 respectively)[Fig. 1]
Conclusions: High SVV and OI during and after suprarenal AAA surgery are associated with high risk of AKI.
