Comparison of bicarbonate-buffered fluid and isotonic saline solution as Cell Saver washing fluids for packed red blood cells

[Improved quality of stored packed red blood cells by mechanical rinsing]

BACKGROUND

The transfusion of packed red blood cells (PRBC) is associated with various side effects, including storage damage to PRBCs. The cells change their structure, releasing potassium as well as lactate. Mechanical rinsing, available in many hospitals, is able to remove toxic substances and possibly minimizes the negative side effects of transfusion.

OBJECTIVE

The primary aim of our study was to improve the quality of PRBCs before transfusion. The effects of different washing solutions on PRBC quality were analyzed.

MATERIAL AND METHODS

This in vitro study compares 30 mechanically washed PRBCs. They were either processed with standard normal saline 0.9% (n = 15, N group) or a hemofiltration solution containing 4 mmol/l potassium (n = 15, HF group) by a mechanical rinsing device (Xtra, LivaNova, Munich, Germany). A subgroup analysis was performed based on the storage duration of the processed PRBCs (7, 14, 37 days). Samples were taken before washing (EKprä), immediately after washing (EKpost) and 10 h later (EKpost10h), after storage in the "wash medium" at room temperature. Concentrations of ATP (probability of survival in transfused erythrocytes), lactate, citrate and electrolytes (potassium, sodium, chloride, calcium) were tested.

RESULTS AND CONCLUSION

Mechanical rinsing improves pretransfusion quality of PRBC. Washing with a hemofiltration solution results in a more physiological electrolyte composition. Even 10 h after mechanical rinsing with a hemofiltration solution, the quality of 37-day-old PRBC is comparable to young PRBC that have been stored for 7 days and have not been washed. Washing stored PRBC increases the ATP content, which subsequently leads to an increased probability of survival of red cells after transfusion.

Bronchospasm and Kidney Injury Associated With Salvaged Blood Reinfusion During Pediatric Neurosurgical Procedure: A Case Report

Adverse events associated with salvaged blood reinfusion are common, but bronchospasm has been rarely reported, especially in pediatrics. We report the case of a child undergoing epileptogenic focus resection, who experienced bronchospasm and kidney injury associated with reinfusion of salvaged blood, presumably related to excessive free hemoglobin.

In Vitro and In Vivo Comparison of Hemoglobin and Electrolytes Following the Collection of Cell Saver Blood Washed with Either Normal Saline or Plasma-Lyte A

Cell saver blood is typically washed with normal saline (NS); however, recent studies have reported decreased red blood cell hemolysis and increased platelet function when a more physiologic washing solution, such as Plasma-Lyte A (PL-A) is used. We evaluated the in vitro and in vivo effects of NS compared to PL-A as washing solutions for cell saver blood in pediatric cardiac surgery. Cell saver blood was re-infused for up to 24 hours post-collection. Laboratory and clinical data were collected from infants receiving cell saver washed with either NS (n = 20) or PL-A (n = 21). Compositions of the cell saver blood were compared between groups at 5 in vitro time points and in vivo patient blood at 24 hours post-bypass. Although there were differences in in vitro laboratory values between groups; 24 hours post-bypass, in vivo results were similar. Our data supports 24-hour reinfusion of cell saver washed with either NS versus PL-A in pediatric cardiac surgery patients, and provides data on the differences in cell saver composition to guide future studies.

The Optimal Cell Salvage Settings to Maximize Hematocrit and Minimize Potassium Using the Cobe BRAT2 Autologous Blood Recovery Unit

OBJECTIVE

The objective was to determine the optimal cell saver device settings (infusion rate and wash rate) at which hematocrit is preserved and potassium and lactate are removed from banked red blood cells (RBC).

DESIGN

Red cells were washed using the Cobe BRAT 2 Autologous Blood Recovery Unit and sampled for electrolyte composition and hematocrit pre- and postwash.

SETTING

This was a single-center study.

INTERVENTIONS

Red cells were washed using six infusion rates (100-1,000 mL/min) and six wash rates (100-1,000 mL/min) for a total of 36 combinations. Hematocrit, potassium, glucose, and lactate were evaluated before and after washing.

MEASUREMENTS AND MAIN RESULTS

At wash rates ≤400 mL/min, hematocrit increased independent of infusion rate. At wash rates ≥400 mL/min, slower infusion rates were associated with higher hematocrit compared to faster infusion rates (p < 0.0001 for a wash rate 400-800 mL/min, p < 0.0005 for a wash rate 1,000 mL/min). Maximal wash speeds were associated with decreasing hematocrit. Infusion and wash rate were both independent predictors of potassium change; slower rates were associated with a larger decrease in potassium. Glucose decreased proportionally as infusion and wash rate decreased. Lactate did not show an association with either infusion or wash rate.

CONCLUSION

Red-cell washing produces higher hematocrit and lower potassium as infusion rate and wash rate decrease. A 340-mL unit of RBC can be processed in 4.26 minutes without loss of hematocrit or an increase in potassium when both infusion and wash rates are set to 400 mL/min.

Intraoperative Cell Saving: Is the Solution the Actual Problem?

Allogenic blood is a scarce, precious, and expensive resource that is not always available on demand. After termination of cardiopulmonary bypass, a large amount of residual pump blood remains in the extracorporeal circuit. The cell saver washes and concentrates this blood with .9% normal saline (NS), making autologous blood available and reducing the demand for allogenic blood. To quantify the quality of residual pump blood it was washed with either NS or a bicarbonate-buffered solution (Balsol). A qualitative in vitro analysis was conducted. Residual cardiopulmonary bypass blood from forty bypass circuits was processed with a cell saver device, using NS or Balsol solution. Measurements made compared the pH, electrolytes, metabolites, hematocrit, hemoglobin, osmolality, albumin, total protein, and strong ion difference. There were significant differences between the NS and Balsol groups. In the Balsol group, osmolality, electrolytes, and strong ion difference were similar to the constitution of Balsol solution after washing, but not with the normal saline group. Washing residual cardiopulmonary bypass pump blood with Balsol solution results in a resuspended red cell concentrate with a superior electrolyte profile and a strong ion difference similar to that of residual pump blood.

0.9% NaCl (Normal Saline) - Perhaps not so normal after all?

Crystalloid infusion is widely employed in patient care for volume replacement and resuscitation. In the United States the crystalloid of choice is often normal saline. Surgeons and anesthesiologists have long preferred buffered solutions such as Ringer's Lactate and Plasma-Lyte A. Normal saline is the solution most widely employed in medical and pediatric care, as well as in hematology and transfusion medicine. However, there is growing concern that normal saline is more toxic than balanced, buffered crystalloids such as Plasma-Lyte and Lactated Ringer's. Normal saline is the only solution recommended for red cell washing, administration and salvage in the USA, but Plasma-Lyte A is also FDA approved for these purposes. Lactated Ringer's has been traditionally avoided in these applications due to concerns over clotting, but existing research suggests this is not likely a problem. In animal models and clinical studies in various settings, normal saline can cause metabolic acidosis, vascular and renal function changes, as well as abdominal pain in comparison with balanced crystalloids. The one extant randomized trial suggests that in very small volumes (2 l or less) normal saline is not more toxic than other crystalloids. Recent evidence suggests that normal saline causes substantially more in vitro hemolysis than Plasma-Lyte A and similar solutions during short term storage (24 hours) after washing or intraoperative salvage. There are now abundant data to raise concerns as to whether normal saline is the safest replacement solution in infusion therapy, red cell washing and salvage, apheresis and similar uses. In the USA, Plasma-Lyte A is also FDA approved for use with blood components and is likely a safer solution for these purposes. Its only disadvantage is a higher cost. Additional studies of the safety of normal saline for virtually all current clinical uses are needed. It seems likely that normal saline will eventually be abandoned in favor of safer, more physiologic crystalloid solutions in the coming years.

Effects of potassium adsorption filters on the removal of ammonia from blood products

BACKGROUND

Although ammonia in plasma does not usually pass through the blood-brain barrier (BBB), in cases of traumatic brain injury it may do so, acting as a neurotoxin on the brain. Excess intake of ammonia should be restricted in conditions involving BBB breakdown, such as traumatic brain injury. Washing is a method to remove ammonia from blood products, but fresh-frozen plasma and albumin products cannot be washed. A potassium adsorption filter (PAF) can remove not only potassium, but also ammonia from red blood cell solutions. We, therefore, examined the effects of a PAF on the removal of ammonia from a range of blood products.

MATERIALS AND METHODS

Ammonia concentrations were measured in expired red blood cell solutions, fresh-frozen plasma, and platelet concentrates and purchased albumin products before and after filtration through a PAF. The PAF was primed with saline, which was removed before the filter was used.

RESULTS

The percentages of ammonia removal from the red blood cell solutions, fresh-frozen plasma, plasma concentrates, 20% albumin and 5% albumin were approximately 76-87%, 21-31%, 53%, 77-92% and 49-63%, respectively.

DISCUSSION

A PAF appears capable of removing ammonia from a range of blood products, although the reason for the lesser effect on the ammonia concentration in fresh-frozen plasma compared to other blood products remains unknown. We hypothesise that, by lowering ammonia levels in blood products, the PAF could improve the clinical prognosis of neonates with an underdeveloped BBB or patients with BBB breakdown following traumatic brain injury.