Analysis of factors responsible for blood loss during scoliosis correction surgeries

Abstract

The present analysis was conducted retrospectively to determine the importance of factors which can affect blood loss in scoliosis surgery. Data of the 30 patients who underwent surgery for correction of scoliosis by using various instrumentation and non-instrumentation techniques with bone grafting in period of one year was collected. The mean intraoperative blood loss was 424.66 ± 342.07ml which was 21.45 ± 13.37 percent of estimated blood volume. The mean total blood loss (intraoperative + drain output) was 488 ± 361.72 i.e 24.78 ± 14.22 percent of estimated blood volume. The mean total blood administration was 472.82 ± 302.96 ml. Introperative blood loss was significantly related with duration of surgery (r= 0.845, P< 0.001). When surgery lasted less than 6 hrs the mean intraoperative blood loss was 234.7 ± 171.39 ml and when the duration was more than 6hrs intraoperative blood loss was 673.07 ± 354.5 ml (P < 0.001). Number of fused vertebrae were related with intraoperative blood loss (r= 0.632, P<0.01) but more significantly related with total blood loss (r= 0.766, P <0.001). When less than seven vertebrae were fused the mean intraoperative blood loss and the mean total blood loss was 236.87 ± 217.36 ml and 277.81 ± 227.91 ml respectively. In case of more than seven vertebral fusion the mean intraopertive blood loss was 639.28±336.94 (P= 0.003) and total blood loss was 728.21 ±336.94 ml (P= 0.001). A poor correlation was obtained with the mean intraopertive blood loss and Cobb’s angle (r=0.468, P<0.02) but a better correlation was observed with the mean total blood loss (r= 0.541, P< 0.01). There was a significant correlation between the mean intraoperative blood loss (P< 0.005) and total blood loss (P<0.008) with the wake up test when it was performed. Mean arterial blood pressure was not related with intraoperative as well as total blood loss.