Limited effectiveness of intraoperative autotransfusion in major back surgery:

Role of Amicar in surgery for neuromuscular scoliosis

STUDY DESIGN

A retrospective case-control study.

OBJECTIVE

Evaluate the effectiveness of Amicar in decreasing perioperative blood loss in patients with neuromuscular scoliosis undergoing posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI).

SUMMARY OF BACKGROUND DATA

Previously, a preliminary prospective; prospective randomized double-blind; same-day anterior and posterior spinal fusion; and fibrinogen studies have demonstrated Amicar to be effective in decreasing total perioperative blood loss and transfusion requirements in surgery for idiopathic scoliosis. Increased fibrinogen secretion is a possible explanation. We are now analyzing its effectiveness in neuromuscular scoliosis.

METHODS

Amicar was administered at 100 mg/kg over 15 minute not to exceed 5 g after anesthesia induction. Maintenance is 10 mg/kg/h until wound closure. There were 2 study groups: group 1 (n = 34), no Amicar and group 2 (n = 62) who received Amicar. The majority of patients in both groups had cerebral palsy. Total perioperative blood loss was determined from the estimated intraoperative blood loss and measured postoperative suction drainage. Total perioperative blood loss and transfusion requirements (cell saver and allogeneic) were compared using chi or Fisher exact test.

RESULTS

There was statistically less estimated intraoperative blood loss, total perioperative blood loss, and transfusion requirements in group 2. Postoperative suction drainage was also less but did not reach statistical significance. In group 1, estimated intraoperative blood loss, measured postoperative suction drainage, and total perioperative blood loss were 2194 +/- 1626 mL, 903 +/- 547 mL, and 3055 +/- 1852 mL, whereas in group 2, it was 1125 +/- 715 mL, 695 +/- 489 mL, and 1805 +/- 940 mL. Transfusion requirements were 1548 +/- 962 mL in group 1 but only 660 +/- 589 mL in group 2 (P < 0.0001). Amicar was equally effective in all diagnoses. There were no complications related to the use of Amicar.

CONCLUSION

Amicar was highly effective in decreasing perioperative blood loss and transfusion requirements in patients with neuromuscular scoliosis undergoing PSF and SSI. It was most effective in decreasing estimated intraoperative blood loss. This results in decreased transfusion requirements, costs, and potential transfusion-related complications.

Transfusion of post-operative shed blood: laboratory characteristics and clinical utility

Increased awareness of the potential hazards of allogenic blood transfusion, such as incompatibility reactions, metabolic and immunologic disorders, or transmission of viral diseases, has led to an emphasis on allogeneic blood alternatives. For orthopaedic surgery, several autologous transfusion modalities have emerged as alternatives to allogeneic blood transfusion, avoiding its immunomodulatory effects. Among them, transfusion or return of post-operative salvaged shed blood has become popular in major orthopaedic procedures. However, although the effectiveness of this blood-saving method is well documented, several authors have questioned its safety and recommended the use of washed blood. Therefore, this review analyses the haematologic characteristics of unwashed filtered shed blood, including metabolic status and survival of red blood cells, the components of the haemostatic system, the content of fat particles, bacterial and tumour cells and the possibility of their removal, the content of inflammatory mediators, and the effects on the patient's immune system. From data reviewed in this paper, it can be concluded that post-operative salvage of blood seems to be an excellent source of functional and viable red cells without many of the transfusion-related risks and with some immuno-stimulatory effects. In addition, from our experience, post-operative re-infusion of unwashed shed blood after major spine procedures has proved to reduce post-operative homologous transfusion requirements and to complement pre-operative autologous blood donation, without any clinically relevant complication.

Preoperative erythropoietin in spine surgery

Spine surgery may be associated with profuse intraoperative bleeding that often requires blood transfusions. In recent years several techniques have been developed to avoid allogenic transfusions and their potential complications to surgical patients. In this study we review and analyse the role of preoperative recombinant human erythropoietin (rHuEPO) administration in spine surgery as a blood conservation strategy. Between 1998 and 2002, a total of 250 patients scheduled for spine surgery were included in our blood-sparing program: 114 patients (group 1), operated on before rHuEPO approval (2000), underwent preoperative autologous blood donation (ABD) alone, and 136 patients operated on after rHuEPO approval (groups 2 and 3) received rHuEPO while undergoing ABD. Adding rHuEPO to ABD resulted in higher haemoglobin and haematocrit values the day of surgery, more ABD units retrieved per patient and, consequently, reduced allogenic transfusion requirements. The effectiveness of rHuEPO as the only preoperative blood conservation technique was evaluated in ten patients with a predicted blood loss of less than 30% of their total volume, scheduled for lumbar surgery. Data from these patients were matched with those from a similar group of patients who had undergone ABD. Patients receiving rHuEPO alone had higher haemoglobin levels the day of surgery than did patients in the ABD program. Neither group required allogenic transfusions.

CONCLUSIONS

preoperative rHuEPO is useful for reducing allogenic blood requirements in elective spine surgery. In patients with an expected blood loss of around 50% of blood volume, rHuEPO improves ABD, minimising preoperative anaemia and increasing the number of ABD units collected. In patients with expected blood loss below 30% of total volume, rHuEPO administration may replace ABD.