Detection and removal of fat particles from postoperative salvaged blood in orthopedic surgery

Self-anticoagulant sponge for whole blood auto-transfusion and its mechanism of coagulation factor inactivation

Clinical use of intraoperative auto-transfusion requires the removal of platelets and plasma proteins due to pump-based suction and water-soluble anticoagulant administration, which causes dilutional coagulopathy. Herein, we develop a carboxylated and sulfonated heparin-mimetic polymer-modified sponge with spontaneous blood adsorption and instantaneous anticoagulation. We find that intrinsic coagulation factors, especially XI, are inactivated by adsorption to the sponge surface, while inactivation of thrombin in the sponge-treated plasma effectively inhibits the common coagulation pathway. We show whole blood auto-transfusion in trauma-induced hemorrhage, benefiting from the multiple inhibitory effects of the sponge on coagulation enzymes and calcium depletion. We demonstrate that the transfusion of collected blood favors faster recovery of hemostasis compared to traditional heparinized blood in a rabbit model. Our work not only develops a safe and convenient approach for whole blood auto-transfusion, but also provides the mechanism of action of self-anticoagulant heparin-mimetic polymer-modified surfaces.

Biochemical effects of intraoperative cell salvage and autotransfusion during cesarean section: A prospective pilot study

AIM

Intraoperative cell salvage and autotransfusion (ICSA) is a useful technique for women undergoing cesarean sections who are predicted to experience significant bleeding. This method can reduce allogeneic transfusions as well as its associated risks and costs. Amniotic fluid embolism (AFE) is an abnormal maternal response to ICSA similar to the classic systemic inflammatory response syndrome, but its mechanism is not well understood. This study was conducted to investigate the biochemical aspects of AFE.

METHODS

A prospective case-controlled pilot study was conducted in a general perinatal hospital in Japan. ICSA was performed using a two-step retransfusion process. Blood samples were collected presurgery, immediately postsurgery, and 24 h after surgery. Changes in sialyl Tn antigen (STN), complement C3 and C4, fibrinogen, and fibrin degradation product and D-dimer, C1 esterase inhibitor, and interleukin-8 (all considered AFE-related markers) activities were compared between patients who underwent cesarean sections with ICSA (ICSA group) versus without ICSA (control group).

RESULTS

Fibrinogen levels were significantly lower in the ICSA group than in the control group before surgery but not immediately after or 24 h after surgery. D-dimer was significantly higher immediately after surgery but not 24 h later. STN was significantly lower only before surgery. None of the AFE-related markers showed significant differences between the groups after 24 h. No adverse events were observed in the ICSA group.

CONCLUSIONS

There is no clinical evidence that ICSA alters the biochemical statuses of AFE-related markers in a manner that could lead to adverse maternal responses.

Intraoperative cell salvage use reduces the rate of perioperative allogenic blood transfusion in patients undergoing periacetabular osteotomy

Blood loss during periacetabular osteotomy (PAO) is variable, with losses ranging from 100 to 3900 ml in published series. Perioperative allogenic blood transfusion is frequently utilized although is associated with significant risk of morbidity. Cell salvage (CS) is a common blood conservation tool; however, evidence supporting its use with PAO is lacking. Our aim was to assess whether CS affects perioperative allogenic blood transfusion rate in patients undergoing PAO. The clinical records of 58 consecutive PAOs in 54 patients (median age 24.7 years, interquartile range 17.8-29.4 years) performed by a single surgeon between 1 January 2016 and 30 April 2018 were reviewed. Autologous blood pre-donation and surgical drains were not used. Due to variable technician availability, CS was intermittently used during the study period. PAOs were allocated into a CS group or no cell salvage group (NCS group), according to whether an intraoperative CS system was used. There was no significant difference in patient age, gender, body mass index, dysplasia severity, regional anesthetic technique, tranexamic acid administration, surgical duration or estimated blood loss (all P > 0.05) between the two groups. The CS group had a lower preoperative hemoglobin compared to the NCS group (median, 13.4 g/dl versus 14.4 g/dl, P = 0.006). The incidence of allogenic blood transfusion was significantly lower in the CS group compared to the NCS group (2.5% versus 33.3% patients transfused, P = 0.003). Multivariate modeling showed CS use to be protective against allogenic blood transfusion (P = 0.003), with an associated 80-fold reduction in the odds of transfusion (odds ratio, 0.01; 95th% CI, 0-0.57). To our knowledge, this is the first study to assess the effect of CS use on allogenic transfusion rate in patients undergoing PAO. Our results demonstrate CS to be a mandatory component of blood conservation for all patients undergoing PAO.

Acute Kidney Injury Secondary to Cell Saver in Posterior Spinal Fusion

BACKGROUND

Autologous blood transfusion, commonly referred to as cell saver, is frequently used in spinal fusion to salvage red blood cells because of the risk of significant intraoperative blood loss. This case report describes a case of acute kidney injury (AKI) secondary to cell saver use. Our objective is to increase the knowledge about the process of red blood cell salvage and this exceedingly rare complication.

METHODS

Chart and renal biopsy results for a single case were reviewed and reported in this retrospective study.

RESULTS

A healthy 18-year-old male patient underwent posterior spinal instrumentation and fusion for adolescent idiopathic scoliosis with utilization of intraoperative autologous blood transfusion. The patient subsequently developed hematuria and AKI with a peak creatinine of 13.9 mg/dL. An extensive clinical workup, including autoimmune serology, excluded any identifying causes. A renal biopsy showed pigment-induced acute tubular necrosis.

CONCLUSIONS

This case, to our knowledge, is the first and only case report of AKI secondary to cell saver demonstrated by renal biopsy. The literature has shown both the benefit of cell saver by decreasing the need for allogeneic transfusion and the risk of transient hematuria. However, this case demonstrates the importance of monitoring patients for potential complications.

Contaminating fat in pericardial suction blood: a clinical, technical and scientific challenge

Stroke and diffuse brain damage after cardiac surgery are too common. It is important to find means to reduce the incidence in view of future competition to surgery from less invasive procedures. Stroke is fairly well defined in clinical terms and with several identified mechanisms. Diffuse brain damage is less well defined and more complex in nature. One suggested mechanism is from cerebral fat microembolization of retrieved pericardial suction blood (PSB). The present study aimed to describe a simple method to measure fat content of PSB, how experimental artefacts interfere with the results, and how the unstable character of a fat-blood suspension can be used to design a simple fat-separation system. The quantity of small amounts of fat can be amplified by centrifugation to the tapered tip of a standard glass pipette. The coefficient of variation after repeated experiments was 9.5%. PSB after coronary bypass surgery contained 0.22±0.04% fat of which 15±3% was bound to the surface of the plastic collecting bag. Experimentation requires standardized routines. Static incubation, blood-fat mixing routines, and transfer steps of blood samples between syringes induce substantial artefacts from spontaneous density separation and surface-adhesion of fat. Soya oil is a common reference substance replacing human fat in technical laboratory science, but is associated with artefacts of its own. These artefacts cause problems during experimentation but the oil is a good resource in the design of a simple fat-separation system

Fat removal during cell salvage: an optimized program for a discontinuous autotransfusion device

BACKGROUND

Fat in wound blood observed in orthopedic or cardiac surgery might pose a risk for fat embolism during blood salvage. Fat removal was optimized in the washing process.

STUDY DESIGN AND METHODS

In an experimental study blood from fresh donations was adjusted to a hematocrit (Hct) of 25% and an admixture of 1.25% human tissue fat. This blood was processed with the cell salvage device XTRA in a modified program mode. Volumetric quantification of fat was performed after centrifugation of blood samples in Pasteur pipettes. From the volumes, the Hct levels and the concentrations of fat and other variables elimination rates and RBC recovery were calculated.

RESULTS

Pretests showed wash volume, wash flow, and process interruptions affecting fat elimination. With the new optimized fat elimination program Pfat removal rate of fat increased to 98.5 ± 0.9% for the 225-mL bowl. The product had a mean Hct of 48.7 ± 1.2% and a RBC recovery rate of 93.5 ± 2.3%. The program conserved the high elimination rates for albumin, heparin, potassium, and free plasma hemoglobin (98.8, 99.3, 95.3, and 94.9%, respectively). Similar high fat removal was also observed with bowls of smaller size, namely, 98.1% for the 175-mL bowl and 98.2% for the 125- and the 55-mL bowls. With test blood of Hct 10% a mean fat elimination of 99.6 ± 01% was observed.

CONCLUSIONS

A special program modification Pfat involving extra washing and RBC concentration steps significantly improves fat removal by the Latham bowl-based autotransfusion device XTRA, thus yielding results equivalent to the continuous cell salvage system.

The merits of cell salvage in arthroplasty surgery: an overview

Arthroplasty entails considerable exposure to allogenic blood transfusion. Cell salvage with washing is a contemporary strategy that is not universally used despite considerable potential benefits. We searched Embase and Medline to determine if blood salvage with washing during primary and/or revision hip and knee arthroplasty results in lower rates of transfusion and postoperative complications. We included 10 studies in our analysis, which we rated according to Downs and Black criteria. With primary knee arthroplasty, there was a reduction in transfusion rate from 22% to 76% and a 48% reduction in transfusion volume (n = 887). With primary hip arthroplasty, there was a reduction from 69% to 73% in transfusion rate and a 31% reduction in transfusion volume (n = 239). There was a significant decrease in length of hospital stay (9.6 v. 13.6 d). Studies of revision arthroplasty reported a 31%-59% reduction in transfusion volume (n = 241). The available evidence demonstrates reduced exposure to allogenic blood with the use of salvage systems. Studies have been underpowered to detect differences in infection rates and other postoperative complications. Future cost analysis is warranted.

Washing and filtering of cell-salvaged blood - does it make autotransfusion safer?

Autologous transfusion was first performed in the late 1800s, but it was not until the 1970s that devices were developed that enabled widespread adoption of the practice. Unwashed salvaged blood contains thrombogenic products, cell breakdown products and plasma proteins, and gross chemical, cellular and physical contaminants. Washing and filtering of salvaged blood is routinely performed to remove or reduce these elements. In this paper we review the clinical data supporting the need for washing and filtering of salvaged blood.

Sedimentation method for preparation of postoperatively salvaged unwashed shed blood in orthopaedic surgery

BACKGROUND

Salvage and return of unwashed shed blood (USB) after total knee replacement (TKR) is an established blood-saving technique, but some authors question its efficacy and safety and suggest that the shed blood be washed before returning. We evaluated a colloid-based sedimentation method for improving and standardizing the quality of USB collected after TKR without the need for washing.

METHODS

Experiments were performed to find the optimal colloid dose and sedimentation time using diluted donated venous blood. USB samples (n=52) were drawn from the reinfusion bag and mixed with hydroxyethyl starch or gelatine solutions (15-30%, colloid solution volume/total volume × 100). USB red blood cells (RBCs) were allowed to settle by gravity for 30 min, supernatant was evacuated from the syringe, and RBC concentrate was analysed. RBC recovery and other blood cell and chemical removal were calculated according to changes in USB volume and haematocrit. Twenty-five samples from leucodepleted packed RBCs were analysed as a comparator group.

RESULTS

Mean haemoglobin (Hb) of USB was 10.9 g dl(-1). After colloid treatment, 90% of RBCs were recovered, and USB Hb was similar to that of leucodepleted packed RBCs (n=25) (18.9 vs 19.6 g dl(-1), respectively; P=NS). In addition, the procedure reduced USB content of leucocytes (60%), platelets (48%), total protein (76%), cytokines (70-77%), and plasma-free haemoglobin (53%), without major differences between colloids.

CONCLUSIONS

Sedimentation of USB with colloid solutions provides a low-cost alternative for improving and standardizing the quality of salvaged USB after TKR.

Cardiorespiratory effects of venous lipid micro embolization in an experimental model of mediastinal shed blood reinfusion

BACKGROUND

Retransfusion of the patient's own blood during surgery is used to reduce the need for allogenic blood transfusion. It has however been found that this blood contains lipid particles, which form emboli in different organs if the blood is retransfused on the arterial side. In this study, we tested whether retransfusion of blood containing lipid micro-particles on the venous side in a porcine model will give hemodynamic effects.

METHODS

Seven adult pigs were used. A shed blood surrogate containing 400 ml diluted blood and 5 ml radioactive triolein was produced to generate a lipid embolic load. The shed blood surrogate was rapidly (<2 minutes) retransfused from a transfusion bag to the right atrium under general anesthesia. The animals' arterial, pulmonary, right and left atrial pressure were monitored, together with cardiac output and deadspace. At the end of the experiment, an increase in cardiac output and pulmonary pressure was pharmacologically induced to try to flush out lipid particles from the lungs.

RESULTS

A more than 30-fold increase in pulmonary vascular resistance was observed, with subsequent increase in pulmonary artery pressure, and decrease in cardiac output and arterial pressure. This response was transient, but was followed by a smaller, persistent increase in pulmonary vascular resistance. Only a small portion of the infused triolein passed the lungs, and only a small fraction could be recirculated by increasing cardiac output and pulmonary pressure.

CONCLUSION

Infusion of blood containing lipid micro-emboli on the venous side leads to acute, severe hemodynamic responses that can be life threatening. Lipid particles will be trapped in the lungs, leading to persistent effects on the pulmonary vascular resistance.

The utility of the perioperative autologous transfusion system OrthoPAT in total hip replacement surgery: a prospective study

BACKGROUND

Total hip replacement (THR) is associated with a significant perioperative blood loss, and 30-50% of these patients receive allogeneic blood transfusion (ABT). We evaluated the clinical utility of washed shed blood (WSB) return to reduce ABT in THR patients.

STUDY DESIGN AND METHODS

Data from 108 consecutive THR patients were prospectively collected. WSB salvage and reinfusion (OrthoPAT) was intended for 60 (Reinfusion group), whereas the remaining 48 patients served as control group. Patients received ABT if haemoglobin <8 g/dl or clinical signs and symptoms of acute anemia.

RESULTS

WSB return was possible in 49 patients (205 +/- 151 ml of erythrocyte/patient), without any clinically relevant incident. Return of WSB decreased both the ABT rate (48 vs. 15%, for control and reinfusion groups, respectively; P = 0.001) and the ABT index (371 +/- 154 ml RBC vs. 53 +/- 117 ml RBC, respectively; P = 0.001), without differences between cemented and uncemented THR. In addition, patients from reinfusion group showed a trend to lower postoperative infection rate (10 vs. 2%, respectively; P = 0.086).

CONCLUSIONS

Perioperative salvage and return of WSB in THR seems to effectively reduce the requirements for ABT. However, for patients with preoperative Hb < 13 g/dl, some additional blood saving method should be associated to WSB return.

Effect of shed blood retransfusion on pulmonary perfusion after total knee arthroplasty: a prospective controlled study

Postoperative shed blood retransfusion (autotransfusion) is a commonly used salvage method following major surgical operations, such as total knee arthroplasty (TKA). The systemic effects of shed blood are still unclear. We studied the effect of residual substances in the retransfused shed blood, on lung perfusion after TKA. Fifteen unilateral and one bilateral TKAs were performed with autotransfusion (the study group) and 15 unilateral and three bilateral TKAs were performed in a control group. Lung X-rays, arterial blood gases (ABG), D-dimer values, and lung perfusion scintigraphies were performed preoperatively and postoperatively. A mean of 300.0 +/- 335.6 ml of bank blood was needed in the autotransfusion group and a mean of 685.7 +/- 365.5 ml of bank blood was needed in the control group (p=0.001). There was a postoperative segmental perfusion defect at the lateral segment of the superior lobe of the left lung in one patient of the control group and he also had risk factors for thrombosis. Although both groups had a decrease in lung perfusion postoperatively, there were no significant differences among the groups regarding the lung perfusion scintigraphy, chest X-rays, ABG, and D-dimer values. In conclusion, although pulmonary perfusion diminishes following TKA, shed blood retransfusion does not add any risk to pulmonary perfusion.

Clinical Efficacy and Biocompatibility of Three Different Leukocyte and Fat Removal Filters During Cardiac Surgery

Activated leukocytes and fat particles are associated with organ injury after a cardiac surgery. Filters are currently used to remove either leukocytes or fat particles. A novel approach with a filter that combines leukocyte and fat removal might be clinically useful. As it is not known which type of filter has a good and safe performance in both leukocyte and fat removal, we measured in this study the leukocyte and fat removal properties and the biocompatibility of three different filters. We used six Pall RS1 (Pall, Portsmouth, England) leukocyte removal filters, six Pall LipiGuard fat removal filters, and six Fresenius Biofil 02 (Fresenius, Emmer-Compascuum, The Netherlands) leukocyte removal filters and measured the passage times of 500 and 1000 mL of residual heart-lung machine blood. We determined the circulating leukocyte and platelet counts, and total hemoglobin, triglyceride, and free fatty acid concentration after the filters. In addition, we measured free hemoglobin, plasma elastase (Merck, Darmstadt, Germany), and complement C5-9 (Quidel, San Diego, CA, U.S.A.) to assess the biocompatibility of the filters. The circulating fat particles were calculated with an automated hematology analyzer. The passage time for the blood was shortest for the Biofil filter (P = 0.02, analysis of variance). The total leukocyte counts (P = 0.04) and fat particles (P = 0.02) were higher after the LipiGuard filter. This filter also had a higher increase in free hemoglobin concentration (P = 0.03). We conclude that the leukocyte removal filters were superior to the fat removal filter both in leukocyte and fat removal.

Quality of drainage blood: survival of red cells after re-transfusion and content of free hemoglobin and potassium

Re-transfusion of drainage blood is widely used in orthopedic surgery, but objective evidence of the efficacy of re-transfusion of drainage blood in view of post-transfusion survival of RBC has not been given so far. With this study we wanted to evaluate the efficacy and safety of transfusion of drainage blood collected with HandyVac autotransfusion system. In 7 patients red cells in drainage blood were labeled with biotin and percentage of labeled red cells in circulation were determined immediately after re-transfusion, and during 10 days after surgery. To assess further unwanted side-effects of re-transfusion of drainage blood potassium and free hemoglobin were determined in the collected blood. Ten days after re-transfusion at mean 78.9% of drainage-blood derived RBC were found in circulation. Free hemoglobin in drainage blood ranged from 16.8 to 59.2 mg/dL; potassium in drainage blood ranged from 3.84 to 4.52 mmol/L. Our results suggest that re-transfusion of drainage blood collected with HandyVac autotransfusion system is an efficient procedure that seems to be safe in view of free hemoglobin and potassium in the product.

Impact of postoperative shed blood transfusion, with or without leucocyte reduction, on acute-phase response to surgery for total knee replacement

BACKGROUND

In patients undergoing total knee replacement (TKR) most blood loss occurs postoperatively and return of unwashed filtered shed blood (USB) from postoperative drainage may represent an alternative to allogeneic blood transfusion (ABT). We evaluated the impact of USB return, with or without leucocytes, on the acute-phase response (APR) after TKR.

PATIENTS AND METHODS

Forty-eight TKR patients, intended to receive postoperative USB, entered the study. Blood samples were obtained before and 6, 24, 72 h and 7 days after surgery, and from the USB before and after it passed through a 40-microm filter (Group F40) or a leucocyte-reduction filter (Group LRF). Haematimetric parameters, APR proteins (albumin, prealbumin, ceruloplasmin, haptoglobin, C-reactive protein), complement C3 and C4, and cytokines (IL-1beta, IL-6, IL-8, IL-10, and TNF-alpha) were measured in all samples.

RESULTS

Twenty-eight patients (Group F40=14, Group LRF=14) received a mean of 1.2 USB units, without any clinically relevant incident, and did not need additional ABT. Sixteen out of the 20 remaining patients who received neither USB nor ABT served as a control group for the postoperative APR study. All patients showed the typical postoperative APR profile and there were no significant differences between groups for APR parameters, postoperative complications, or hospital stay.

CONCLUSIONS

Postoperative blood salvage and return, with or without a LRF, after TKR does not present any clinically relevant side-effects and does not modify APR induced by surgery. These findings seem to confirm the clinical experience that postoperative USB return is safe and questions the beneficial effect of using LRF.

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.

Intraoperative red cell salvage

In this article, Tony Fisher explores the background to autotransfusion and how recent advances in equipment and techniques have facilitated intraoperative cell salvage, thus reducing the need for homologous transfusion.

Effect of autologous salvaged blood on postoperative natural killer cell precursor frequency

BACKGROUND

Immunosuppression after major surgery increases the risk of infections. Natural killer cells play a pivotal part in defence against infection. We aimed to investigate the immunomodulatory effects of different types of postoperative blood transfusion by use of a new assay for measuring the frequency of peripheral blood natural killer precursor cells (NKpf assay).

METHODS

We measured the natural killer cell precursor (NKp) frequency before and 5 days after surgery in 120 patients undergoing joint replacement surgery. The patients were assigned to one of five groups according to the type of transfusion received: non-transfused (n=32), allogeneic non-leukodepleted blood (eight), allogeneic leukodepleted blood (30), autologous predeposited blood (ten), and autologous salvaged blood collected within the first 24 h after surgery (40). We also measured interferon gamma and interleukin 10 concentrations before and after surgery.

FINDINGS

The mean postoperative NKp frequency for all patients was lower than the preoperative values, except in patients receiving autologous salvaged blood, which was higher than all other groups (p<0.0001). Postoperative NKp frequencies for patients receiving allogeneic or autologous predeposited blood responded similarly (p=0.99), but these patients had lower NKp frequencies than did the non-transfused group (p<0.0001). Postoperative interferon gamma concentrations were higher in the autologous salvaged blood group (p<0.0001) than in other groups, which did not differ from each other. Interleukin 10 concentrations were similar across all groups (p=0.49).

INTERPRETATION

Immunosuppression associated with surgery and blood loss was reflected in a reduced frequency of NKp and decreased interferon gamma. This immunosuppression was reversed by transfusion of autologous salvaged blood, suggesting that this fluid contained immunostimulants.

Fat reduction in pericardial suction blood by spontaneous density separation: an experimental model on human liquid fat versus soya oil

Pericardial suction blood (PSB) contains mediastinal liquid wound fat with an embolic potential to cause brain damage after cardiopulmonary bypass (CPB). The aims were to measure how fat separates spontaneously from blood by density and how temperature and fat surface adhesion affect the results under experimental conditions. Human liquid fat was heat-extracted from retrieved pericardial fat tissue of coronary artery bypass graft (CABG) patients (n = 10). Human fat or soya oil, 5% and 10%, respectively, were mixed with postoperatively shed mediastinal blood (n = 20). The mixture was loaded into a temperature-controlled (37 degrees C, 20 degrees C, 10 degrees C) vertical separation column. At 1, 2.5, 5 and 10 minutes, the blood was collected in five fractions, representing layers of density separation, followed by centrifugation. Human fat solidified at 8 degrees C. Soya oil remained liquid below 0 degrees C. Soya oil separated fast in water, but was slower in blood. At 10 minutes and 37 degrees C 73 +/- 6% of added soya oil was found in the top 20% fraction. Human fat at 37 degrees C behaved similarly to soya oil, with 58 +/- 2% separation at 10 minutes. However, at lower temperatures the density separation became less efficient (p < 0.001), whereas human fat more effectively adhered to the walls of the column, which added to the removal. In total, 66%-78% of the human fat was removed, depending on temperature. In conclusion, fat in PSB can be reduced by simple density separation and surface adhesion while it is temporarily retained from the CPB circuit.