Renal perfusion pressure and capillary leaks index as risk factors for acute kidney injury after major abdominal surgery

Background & Objective: Many factors can contribute to the development of acute kidney injury (AKI) following major abdominal surgery, including the effect of fluid extravasation into interstitial space due to capillary leakage. Microalbuminuria is also brought on by capillary leakage. Increased central venous pressure (CVP) or intra-abdominal pressure (IAP) will decrease renal filtration according to the degree of pressure transmission to the glomeruli. The objective of this study was to know the correlation of capillary leakage index (CLI), microalbuminuria [urine albumin to creatinine ratio (ACR)] and renal perfusion pressure (RPP) with the incidence of AKI. Methodology: A prospective longitudinal cohort design with consecutive sampling was used in this study. The parameters capillary leakage index (CLI), microalbuminuria (ACR) and renal perfusion pressure (RPP) were examined preoperatively, and at 12 h and 36 h postoperatively, and the incidence of AKI was observed till the fourth postoperative day. CLI was defined as C-reactive protein (CRP mg/dL) over albumin (g/L) multiplied by 100. RPP as glomerular pressure was obtained from mean arterial pressure (MAP), IAP, and renal venous pressure estimated by CVP, by the formula RPP = MAP-(IAP+CVP). Results: Following major abdominal surgery, 19 (25.68%) of the 74 subjects developed AKI. There was no significant difference in CLI and ACR between patients with and without AKI. Renal perfusion measurements examined at 0, 12, and 36 h showed significantly lower values in AKI patients. The relative risk (RR) of RPP was 9.125 with a 95 % CI of 1.141293-72.95725 (P = 0.037) after data analysis with Cox Regression to establish the correlation between CLI, ACR, and RPP, as well as covariate variables on the occurrence of AKI at 0 h. Compared to participants without AKI, those with AKI had a mortality risk of 2.384 times higher (P = 0.0351, 95 % CI = 1.133-5.018). Conclusion: Renal perfusion pressure showed a significant correlation with acute kidney injury. Additionally, there is a strong connection between acute kidney injury and mortality. Abbreviations: ACR-albumin to creatinine ratio; AKI-acute kidney injury; CLI-capillary leakage index; CVP-central venous pressure; IAP-intra-abdominal pressure; MAP-mean arterial pressure; RPP-renal perfusion pressure