Effect of perioperative fluid therapy on urinary biomarkers in preeclamptic women who underwent caesarean section - A randomised controlled trial.

BACKGROUND: Preeclamptic women are more prone to renal dysfunction due to endothelial injury, renal vasoconstriction and compromised glomerular filtration rate. In the perioperative period, fluids are administered with caution especially in preeclamptic women because crystalloids like normal saline are reported to cause renal vasoconstriction and predispose to acute kidney injury. Existing literature shows limited evidence on the effects of normal saline on the renal function of women with preeclampsia. OBJECTIVES: This study aimed to compare the effects of normal saline (NS) versus Ringer's lactate (RL) on renal injury biomarkers by measuring urinary Neutrophil Gelatinase Associated Lipocalin (NGAL) And Kidney Injury Molecule-1 (KIM-1). METHODS: This prospective randomised clinical study was conducted in a tertiary care hospital from May2021 to October 2022. Pregnant women diagnosed with preeclampsia (with or without severe features) who underwent caesarean delivery under spinal anaesthesia were enrolled and randomised into two groups NS or RL. Primary outcome was to find differences in urinary NGAL and KIM-1 levels at 6 and 12 hours postoperatively. Our secondary outcomes were to determine the correlation between urinary NGAL and KIM-1 with amount of fluids, severity of preeclampsia, and admission systolic and diastolic BP. Any difference in pH, bicarbonate and chloride levels and serum creatinine were also analysed. RESULTS: 120 preeclamptic women were enrolled, and the final data was analysed for urinary NGAL in 113 women and urinary KIM-1 in 104 women. The values of urinary biomarkers were comparable between the two groups (p value =0.76 for NGAL and p value =0.81 for KIM-1).There was no difference in the serum creatinine between the two groups at 48 hours. . Preeclamptic women in the NS group had lower values of pH and HCO3 than the RL group. The NGAL and KIM-1 values in both the groups did not correlate with severity of preeclampsia, amount of fluids, baseline systolic and diastolic blood pressures. CONCLUSION: Peri-operative administration of NS or RL did not have any significant difference on the renal injury biomarkers like NGAL and KIM-1 and serum creatinine in preeclamptic women who had normal renal function, although NS group had low levels of bicarbonate.