Effect of Obesity and Hypertension on Blood Loss and Blood Transfusion Requirements in Primary Elective Total Knee Arthroplasty: A Prospective Clinical Study

Abstract

Introduction: Identifying risk factors of operative blood loss is imperative toward establishing an effective blood management implementation strategy and further minimize the requirement for perioperative blood loss and transfusion. Aim: To investigate whether the factors like obesity and hypertension affect blood loss and transfusion requirements in primary elective Total Knee Arthroplasty (TKA). Materials and Methods: A prospective clinical study was conducted at Shalby Hospitals in Ahmedabad, Gujarat, India, from November 2017 to November 2019, on 91 patients recruited for primary elective TKA. The subjects were divided into two groups, i.e, group A (normotensive and non obese; n=46) and group B (Hypertensive and obese; n=45). Charlson-Deyo comorbidity score were given to each patient as a measure of surgical risk. Data on intraoperative and postoperative blood loss, blood parameters (drop in haemoglobin, haematocrit value), and incidence of transfusion rates were recorded and assessed. All patients had standardized protocols of anesthesia, postsurgical and rehabilitation care protocols following surgery. Fisher’sexact test, Chi-square test, and student’s t-test were used for statistical analysis. Pearson’s correlation was performed to identify factors associated to blood loss. The p-value <0.05 was considered significant. Statistical Package for Social Sciences (SPSS) version 22.0 was used. Results: The intraoperative, postoperative and total blood loss (drop of haemoglobin and haematocrit) were significantly greater in the hypertensive and obese patients (p-value <0.001). The immediate postoperative day 1 haemoglobin and day 1 and 2 haematocrit were significantly better in the normotensive and non obese patients (p-value <0.001). Significantly greater number of hypertensive and obese patients required blood transfusion (p-value=0.045). There was a positive correlation between intraoperative blood loss and operative time in both groups (RA=0.04, p-value=0.74; RB=0.09, p-value=0.52) although statistically insignificant. Hypertensive and obese patients required longer hospitalization (p-value <0.0001). Three patients from group B were diagnosed to develop pulmonary embolism while admitted in hospital which was managed successfully by intensivists without any fatality. Conclusion: Hypertension and obesity were associated with greater blood loss and transfusion requirement compared to non obese and normotensive patients undergoing primary elective TKA.