Basic demographic characteristics of all participants
This study included 402 patients, including 264 (65.67%) women and 138 (34.33%) men, with an average age of 12.87 years (SD, 2.06; range, 9–19), average height of 151.58 cm (SD, 12.43; range, 121.00–179.00), and average weight of 41.03 kg (SD, 9.66; range, 18–63).
In groups A, B, and C, no significant differences were observed in sex, age, height, weight, Cobb angle, preoperative hemoglobin, or hematocrit between patients who used IAT and those who did not (Table 2).
Intraoperative and postoperative conditions of all participants
In groups A, B, and C, no significant differences were observed in the number of vertebral levels fused, surgical duration, total fluid infusion, total plasma infusion, urine volume, volume of intraoperative blood loss, postoperative hemoglobin, and hematocrit values between patients who used IAT and those who did not (Table 3).
In group A, no significant difference was observed in the volume of allogeneic RBC transfused between the patients who used IAT and those who did not (2.66±0.95 units vs. 3.00±1.16 units, P = 0.198). In groups B and C, the volume of allogeneic RBC transfused was significantly reduced in the patients who used IAT than those who did not (Group B: 3.55±1.27 units vs. 4.28±0.71 units, P = 0.003; Group C: 5.00±2.04 units vs. 8.50±1.70 units, P<0.001) (Table 3).
The RBC transfusion cost of all participants
In group A, no significant difference was observed in the allogeneic RBC transfusion-related cost between the patients who used IAT and those who did not (155.48±52.97 USD vs. 173.90±64.50 USD, P = 0.198). In groups B and C, the allogeneic RBC transfusion-related cost in the patients who used IAT was lower than those who did not (Group B: 204.58±70.22 USD vs. 244.92±39.22 USD, P = 0.003; Group C: 284.38±112.75 USD vs. 477.72±93.98 USD, P<0.001) (Table 4).
In groups A and B, patients who used IAT had significantly higher total RBC transfusion costs (allogeneic RBC transfusion-related costs and IAT costs) than those who did not (Group A: 399.31±52.97 USD vs. 173.90±64.50 USD, P<0.001; Group B: 448.42±70.23 USD vs. 244.92±39.22 USD, P<0.001) (Table 4). However, in group C, no significant difference was observed in the total RBC transfusion cost between the patients who used IAT and those who did not (528.21±112.75 USD vs. 477.72±93.98 USD, P = 0.115) (Table 4).
Risk factors associated with massive intraoperative blood loss
A significant difference was observed between the height, weight, Cobb angle, and the number of vertebral levels fused between the patients with intraoperative blood loss ≥500 to <1,000 mL and ≥1,000 mL (P<0.05). Furthermore, a significant difference was observed between the age, height, weight, Cobb angle, and the number of vertebral levels fused between the patients with intraoperative blood loss ≥500 to <1,500 mL and ≥1,500 mL (P<0.05) (Table 5). The results of the multivariate analysis revealed that the number of vertebral levels fused (Volume of intraoperative blood loss ≥1,000 mL: odds ratio [OR]=1.89, 95% confidence interval [CI] 1.37–3.00, P<0.001; volume of intraoperative blood loss ≥1,500 mL: OR=2.04, 95% CI 1.41–2.96, P<0.001) was an independent risk factor for massive intraoperative blood loss (Table 6).
ROC analysis showed that more than eight fused vertebral levels (sensitivity: 0.82, specificity: 0.58, AUC: 0.79, p < 0.01) predicted 1,000 mL or greater intraoperative blood loss (Figure 1). Additionally, more than 10 fused vertebral levels (sensitivity: 0.80, specificity: 0.52, AUC: 0.76, p < 0.01) predicted 1,500 mL or greater intraoperative blood loss (Figure 2).