Humoral immune response to autologous blood transfusion in hip surgery: whole blood versus packed red cells and plasma

Characteristics and quality of intra-operative cell salvage in paediatric scoliosis surgery

OBJECTIVE

To determine the haematological and microbiological characteristics of blood recovered by using a cell saver with a rigid centrifuge bowl (100ml) in paediatric scoliosis surgery and to determine whether it conforms to the standard expected in adult patients.

MATERIAL AND METHODS

A cross-sectional, descriptive cohort study was performed on 24 consecutive red blood cell (RBC) units recovered from the surgical field and processed by a Haemolite® 2+ (Haemonetics Corp., Braintree, MA, EE. UU.) cell saver. Data were collected regarding age, weight, surgical approach (anterior or posterior), processed shed volume and volume of autologous RBC recovered, full blood count, and blood culture obtained from the RBC concentrate, and incidence of fever after reinfusion.

RESULTS

The processed shed volume was very low (939±569ml) with high variability (coefficient of variation=0.6), unlike the recovered volume 129±50ml (coefficient of variation=0.38). A statistically significant correlation between the processed shed volume and recovered RBC concentrate haematocrit was found (Pearson, r=.659, P=.001). Haematological parameters in the recovered concentrate were: Hb 11±5.3g dl(-1); haematocrit: 32.1±15.4% (lower than expected); white cells 5.34±4.22×103 ul(-)1; platelets 37.88±23.5×103 ul(-1) (mean±SD). Blood culture was positive in the RBC concentrate recovered in 13 cases (54.2%) in which Staphylococcus coagulase (-) was isolated.

CONCLUSIONS

Cell salvage machines with rigid centrifuge bowls (including paediatric small volume) do not obtain the expected haematocrit if low volumes are processed, and therefore they are not the best choice in paediatric surgery.

Difference in autologous blood transfusion-induced inflammatory responses between acute normovolemic hemodilution and preoperative donation

PURPOSE

The inflammatory response triggered by transfusion is implicated in the pathophysiology of transfusion-related immunomodulation. The authors hypothesized that two distinctive autotransfusion methods, acute normovolemic hemodilution (ANH) and preoperative donation (PD), have different influences on both inflammatory mediator generation during storage and the inflammatory response after a transfusion. The purpose of this study was to compare the plasma concentrations of neutrophil elastase (NE), interleukin (IL)-6, IL-8, and IL-10 in patients who underwent either of these two autologous transfusion methods.

METHODS

With institutional review board approval, the plasma concentrations of the above inflammatory mediators were determined in 23 patients with ANH and 8 patients with PD at the following time points: after anesthetic induction, at the end of the operation, and the morning of postoperative day 1. The concentrations of these inflammatory mediators were also measured in the donated blood obtained by either ANH or PD before retransfusion.

RESULTS

The mean storage durations were 3.7 h and 6.1 days for ANH and PD, respectively. Higher concentrations of NE and IL-10 were detected in the PD blood than in the ANH blood. Long duration of storage and/or low temperature may have been responsible for the increased NE and IL-10 concentrations in the PD blood. However, the difference between the two groups in the extent of increased plasma concentrations of these inflammatory mediators was not statistically significant.

CONCLUSION

Inflammatory mediators were significantly increased in PD blood during storage compared to the blood obtained by ANH. However, their effects on the inflammatory response elicited in the recipients were not significantly different.

Leukodepletion of autologous whole blood has no impact on perioperative infection rate and length of hospital stay

BACKGROUND

Several mechanisms have been proposed as possible causes of transfusion-related immunomodulation (TRIM) after allogeneic transfusion. If one of these mechanisms, the release of mediators of immunity and inflammation ("biologic response modifiers"[BRMs]) from disintegrating blood cells during storage of blood products, really causes TRIM, it should in principle also occur after autologous transfusion. As a consequence, prestorage leukoreduction of autologous blood should be able to prevent the clinical consequences of TRIM after autologous transfusion.

STUDY DESIGN AND METHODS

This hypothesis was investigated in a multicenter, double-blind, randomized controlled trial. A total of 1089 patients scheduled for total hip arthroplasty and eligible for preoperative autologous blood donation were randomly assigned to receive autologous whole blood (AWB) either unmodified or leukoreduced when transfusion was indicated.

RESULTS

Neither the primary study outcome, that is, the overall postoperative infection rate (17.3% vs. 17.6%, p = 0.59), nor several secondary outcomes like median length of hospital stay (14 days vs. 14 days, p = 0.17) were significantly different between groups, whether analyzed according to the intention-to-treat principle or "as treated."

CONCLUSION

This trial provides strong evidence, from clinically relevant outcome data, that leukoreduction of AWB does not improve postoperative patient outcome and that the release of BRMs from disintegrating blood cells during storage cannot explain the immunomodulatory effect of blood transfusion.

Modern concepts of autologous haemotherapy

The increasing current perception that the safety of allogeneic blood transfusion has dramatically been improved during the last decade is challenging autologous haemotherapy methods. In addition, growing concern about the unfavourable cost-effectiveness of most autologous haemotherapy methods requires a refinement of the application of these measures to well defined circumstances. In contrast, newly emerging transfusion-transmissible infections or periods of blood shortage might revive interest in these blood sparing techniques. Preoperative autologous blood donation still plays a significant role in settings with high individual benefit for the patient, high transfusion probabilities and when all opportunities of cost minimization can be applied. Preoperative plasmapheresis is considered to be a sensible adjunct if intraoperative retransfusion of salvaged and washed red cells is planned. Acute normovolaemic haemodilution is valuable when the patient's tolerability of the haemodilution and the expected blood loss are carefully examined beforehand. Intra- or postoperative salvage of wound blood can also be regarded as useful measures to prevent allogeneic transfusions as long as the specific advantages and disadvantages of the different methods are taken into account. Finally, alternative and supplemental measures such as iron or erythropoietin administration should always be considered in order to optimize the efficacy and effectiveness of autologous haemotherapy methods. The goal of a "bloodless medicine" might not be reached but is supposed to be approached closely with an integrated concept exploiting all measures available. However, in times of restricted health care resources, regular sound cost-effectiveness analyses, taking the availability and the current safety profile of allogeneic blood products into account, are always warranted and needed.

Safety and efficacy of unmodified whole blood vs. buffy coat-depleted red cell concentrates in autologous transfusion of elective orthopaedic surgery patients

Storing autologous blood as whole blood (WB) has been proposed for increasing the cost-effectiveness of preoperative autologous blood donation programmes. However, experimental data suggest that autologous leucocytes might lead to immunomodulation similar to the effect attributed to allogeneic leucocytes. In a retrospective analysis, the postoperative outcome of 120 patients undergoing elective orthopaedic surgery and having donated up to two units of autologous WB (AWB) was compared with that of a control group of 52 patients, whose autologous donation had been processed into buffy coat-depleted red cell concentrates (RCC). At least one autologous unit, but no allogeneic units, had been transfused in all analysed patients. Donation schemes were equally efficacious in both groups. There was no significant difference in postoperative infection rates between the two groups. Overall rates were 7.7% in the RCC group and 8.3% in the WB group. Surgical, thromboembolic and other recorded complications, length of postoperative hospital stay and days of the use of antibiotics were also not significantly different between the two groups. The results of this study suggest that transfusion of up to two units of unmodified AWB is as efficacious as the transfusion of autologous RCC and does not negatively influence the postoperative outcome in elective orthopaedic surgery.