Role of blood urea nitrogen to creatinine ratio in the assessment of hypovolemia who have undergone major surgeries- a cross-sectional study

Abstract Background Major surgeries are being carried for certain ailments. Surgeries can be major or minor depending on the extent of intervention. Major surgeries are prone to cause lots of complications such as shock, haemorrhage, wound infection, deep vein thrombosis, pulmonary complications, organ rejection, reactions to anaesthetics etc. Early identification of complications could reduce morbidity and mortality. Laboratory variables used in the assessment of hypovolemia include blood urea nitrogen, sodium, osmolality, hematocrit, and arterial blood gas. This study was undertaken to assess the utility of blood urea nitrogen: creatinine ratio (BCR) in the utility of assessment of hypovolemia in the first post-operative day in individuals who had major surgeries. Methods and materials The retrospective cross-sectional study included participants from the Departments of Orthopedic Surgery, Obstetrics and Gynecology, General Surgery and Cardiothoracic Surgery. Patients who underwent major surgeries between January 2019 and January 2020 were included. Study participants of 30 to 60 years of both genders were recruited into the study. Data were collected from the Medical Records of a tertiary care hospital in Chennai, India. Ethics approval was obtained, the institutional ethics committee (Ref: CSP/21/SEP/99/479 dated 30–12-2021). Waiver of consent was obtained since the patients were treated and discharged from the hospital. The data were analyzed by SPSS version 16. P value ≤ 0.05 was taken to be significant. Results BCR showed statistically significant difference across the groups with P = 0.02. BCR showed statistically significant difference between cardiac patients with total knee replacement and total abdominal hysterectomy surgeries. BCR showed positive correlation with age, fluids intake and negative correlation with pulse rate and respiratory rate. Conclusion BCR is a simple diagnostic tool for identifying hypovolemia in individuals who undergo major surgeries especially in the first postoperative day. It is significantly altered across the groups with highest value in individuals who have undergone knee replacement surgeries. BCR has high specificity and positive predictive value.