Hidden blood loss after artificial joint replacement and its correlation analysis

Abstract

Objective To calculate the volume and to study the correlated risk factors of hidden blood loss after artificial hip or knee joint replacement. Methods From July to November in 2008, 38patients with age of (65.11±13.51) years old were treated with artificial hip or knee joint replacement, and were divided by age into four groups. Using Gross formula, total blood loss was calculated depending on height, weight and pre- and post-operation hematocrit, and the hidden blood loss was acquired by subtracting the visible blood loss from the total blood loss. The correlation between age,body mass index( BMI),gender and hidden blood blood loss was observed. Differences of hidden blood loss of artificial hip or knee joint replacement were compared. Results The total blood loss of all arthroplasties was ( 1563.52 ± 693.10) ml,and the hidden blood loss was (538.70 ± 529.77) ml,the percentage of hidden blood loss was 33%. The hidden blood loss was inversely related to age (P＜ 0.05 ). There was no correlation between BMI and hidden blood loss (P＞0.05). The percentage of hidden blood loss in total blood loss in woman was significantly higher than that in man. With age and gender paired, the percentage of hidden blood loss in total blood loss in artificial hip joint replacement was significantly higher than that in artificial knee joint replacement (P＜0.05 ). Conclusions Both of age and gender are risk factors influencing hidden blood loss after artificial hip or knee joint replacement. And compared with artificial knee joint replacement, the percentage of hidden blood loss in artificial hip joint replacement is higher. Key words: Blood loss,surgical; Arthroplasty,replacement; Age factors; Gender identity