Role of neutrophil gelatinase-associated lipocalin (NGAL) as a acute prerenal kidney injury marker: Exploring factors associated with its postoperative levels in hypotension-controlled otorhinolaryngology surgery

Introduction: Acute kidney injury (AKI) is a sudden decrease in kidney function due to damage within seven days or less, thus inducing an early stress response that can be promptly detected by biomarkers, such as Neutrophil Gelatinase-Associated Lipocalin (NGAL). The aim of this study was to analyse the role of NGAL level as a biomarker of postoperative prerenal AKI in patients who underwent otorhinolaryngology surgery with controlled hypotension.
Methods: A prospective study was conducted among patients that underwent otorhinolaryngology surgery with controlled hypotension. Patients were selected with purposive sampling. NGAL level was measured using enzyme-linked immunosorbent assay (ELISA) from venous blood collected 1-hour pre- and 2-hour post-surgery. NGAL levels were compared between preoperative and postoperative states. Wilcoxon and Spearman test were used to determine the correlation between NGAL levels and parameters of AKI.
Results: A total of 30 patients underwent a varies of otorhinolaryngology surgeries were recruited in this study. Our data suggested no significant different between the level of NGAL during preoperative and postoperative (184.73±120.09 ng/mL vs 175.80±129.97 ng/mL). Pre-operative laboratory parameters of AKI such as blood urea nitrogen (BUN), serum creatine (SCr), BUN/SCr ratio, and GFR had no correlation with postoperative NGAL level. In addition, systolic blood pressure, diastolic blood pressure, MAP, heart rate, EtCO2, duration of surgery and the duration of controlled hypotension had no correlation with postoperative NGAL.
Conclusion: NGAL levels have nonsignificant role as biomarker of incidence of postoperative prerenal AKI in patients who receiving otorhinolaryngology surgery with controlled hypotension. However, further study with the bigger sample size is warrant to confirm the findings of this study.