Hidden Blood Loss and Factors in Shoulder Arthroscopy Surgery: A Review of 59 Patients

Abstract Purpose: Subacromial impingement syndrome (SIS) and its related rotator cuff tears are the most important cause of shoulder joint pain, which has recently received greater attention. Arthroscopy is a safe, effective, and minimally invasive procedure for the treatment of stage Ⅱ or Ⅲ SIS. Previous studies have reported that little blood loss usually occurs during this procedure. However, significant perioperative hidden blood loss (HBL) is often overlooked. In this respect, we herein aimed to investigate the amount of HBL and identify its possible risk factors.Methods: We enrolled 59 patients with SIS who received shoulder arthroscopy between December 2019 and June 2020 in this study. The clinical data recorded included the height of patients, weight pre- and postoperative hematocrit (Hct), which were used to calculate HBL using Gross’s formula. We analyzed the risk factors, including sex, age, BMI (body mass index), stage of SIS, diabetes, hypertension, and operative time using multivariate linear regression analysis.Results: Our results revealed that the mean of HBL was 341.4 ± 214.9 mL, while that of the postoperative Hb loss was 13.3 ± 8.0 g/L. The incidence of postoperative anemia was significantly associated with HBL (χ2 = 14.496, P < 0.001). Furthermore, multivariate linear regression analysis demonstrated that all seven factors, including gender (P = 0.698), age (P = 0.553), BMI (P = 0.854), stage of SIS (P = 0.906), diabetes (P = 0.984), hypertension (P = 0.532), and operative time (P = 0.645), were not significantly associated with HBL. Conclusion: Findings from this study show that postoperative HBL following shoulder arthroscopy was significant, which can aggravate anemia or lead to secondary anemia, thus should not be neglected.