Jonathan H. Waters

Normal saline versus lactated Ringer's solution for intraoperative fluid management in patients undergoing abdominal aortic aneurysm repair: an outcome study.

Metabolic acidosis and changes in serum osmolarity are consequences of 0.9% normal saline (NS) solution administration. We sought to determine if these physiologic changes influence patient outcome. Patients undergoing aortic reconstructive surgery were enrolled and were randomly assigned to receive lactated Ringer’s (LR) solution (n = 33) or NS (n = 33) in a double-blinded fashion. Anesthetic and fluid management were standardized. Multiple measures of outcome were monitored. The NS patients developed a hyperchloremic acidosis and received more bicarbonate therapy (30 ± 62 mL in the NS group versus 4 ± 16 mL in the LR group; mean ± sd), which was given if the base deficit was greater than −5 mEq/L. The NS patients also received a larger volume of platelet transfusion (478 ± 302 mL in the NS group versus 223 ± 24 mL in the LR group; mean ± sd). When all blood products were summed, the NS group received significantly more blood products (P = 0.02). There were no differences in duration of mechanical ventilation, intensive care unit stay, hospital stay, and incidence of complications. When NS was used as the primary intraoperative solution, significantly more acidosis was seen on completion of surgery. This acidosis resulted in no apparent change in outcome but required larger amounts of bicarbonate to achieve predetermined measurements of base deficit and was associated with the use of larger amounts of blood products. These changes should be considered when choosing fluids for surgical procedures involving extensive blood loss and requiring extensive fluid administration.

Cause of metabolic acidosis in prolonged surgery.

OBJECTIVE The intraoperative development of metabolic acidosis is frequently attributed to hypovolemia, tissue hypoperfusion, and lactic acidosis. In this study, dilutional acidosis was evaluated as a possible mechanism for the routine development of intraoperative acidosis in noncardiac, nonvascular surgery patients. DESIGN Prospective, observational study. SETTING University-affiliated Veterans Affairs Medical Center and a staff model, health maintenance organization hospital. PATIENTS Twelve patients undergoing prolonged surgical procedures expected to last > or = 4 hrs were enrolled in the study. INTERVENTIONS Perioperative management was based on the judgment of the attending anesthesiologist and surgeon without knowledge of the studys intent. MEASUREMENTS AND MAIN RESULTS Arterial blood gas parameters, serum electrolytes, and urine electrolytes were measured pre- and postoperatively. Pulmonary artery catheters were placed for hemodynamic measurement and oxygen delivery calculations. Plasma volume was measured both pre- and postoperatively, using the Evans blue dye dilution technique. Although significant changes in lactate level (1.1 +/- 0.6-1.8 +/- 1.0) occurred, the change was not large enough to explain the degree of change in base excess (0.8 +/- 2.3 to -2.7 +/- 2.9). Chloride levels significantly increased (106 +/- 3-110 +/- 5) with a correlation (r2 = .92; p < .0001) between the degree of change in chloride and the degree of change in base excess. Plasma volume did not change. Furthermore, a correlation between the volume of normal saline administered and the change in base excess was found (r2 = .86; p < .0001), although no correlation was found with Ringers lactate solution. An even stronger correlation was noted when the total chloride amount administered was compared with the change in base excess (r2 = .93; p < .0001). CONCLUSIONS In this patient population, a common source of increasing base deficit is related to chloride administration. The largest source of chloride is usually normal saline. Classically, dilutional acidosis would explain the predominance of this acidotic change; however, no increase in plasma volume occurred. The absence of plasma volume change would suggest that the mechanism postulated to result in dilutional acidosis is incomplete. The common treatment of administering more fluid for intraoperative acidosis may be inappropriate, may have caused the acidosis, and may further exacerbate the acidosis. Chloride levels should be assessed whenever a metabolic acidosis is seen perioperatively.

Detection, evaluation, and management of anemia in the elective surgical patient.

The prevalence of anemia in elective surgical patients may be as frequent as 75% in certain populations. A national audit demonstrated that 35% of patients scheduled for joint replacement therapy have a hemoglobin <13 g/dL on preadmission testing. Standard practice currently consists of preadmission testing 3 to 7 days before an elective operative procedure, precluding the opportunity to effectively evaluate and manage a patient with unexpected anemia. Therefore, a standardized approach for the detection, evaluation, and management of anemia in the preoperative surgical setting was identified as an unmet medical need. To address this knowledge gap, we convened a panel of physicians to develop a clinical care pathway for anemia management in this setting. Elective surgery patients should receive a hemoglobin (Hgb) determination a minimum of 30 days before the scheduled surgical procedure. Because the identification and evaluation of anemia in this setting will assist in expedited diagnosis and treatment of underlying comorbidities and will improve patient outcomes, unexplained anemia (Hgb <12g/dL for females and <13g/dL for males) should cause elective surgery to be deferred until an evaluation can be performed.

Amniotic Fluid Removal during Cell Salvage in the Cesarean Section Patient

Background Cell salvage has been used in obstetrics to a limited degree because of a fear of amniotic fluid embolism. In this study, cell salvage was combined with blood filtration using a leukocyte depletion filter. A comparison of this washed, filtered product was then made with maternal central venous blood. Methods The squamous cell concentration, lamellar body count, quantitative bacterial colonization, potassium level, and fetal hemoglobin concentration were measured in four sequential blood samples collected from 15 women undergoing elective cesarean section. The blood samples collected included (1) unwashed blood from the surgical field (prewash), (2) washed blood (postwash), (3) washed and filtered blood (postfiltration), and (4) maternal central venous blood drawn from a femoral catheter at the time of placental separation. Results Significant reductions in the following parameters were seen when the postfiltration samples were compared to the prewash samples (median [25th–75th percentile]): squamous cell concentration (0.0 [0.0–0.1 counts/high-powered field (HPF)] vs. 8.3 counts/HPF [4.0–10.5 counts/HPF], , P < 0.05); bacterial contamination (0.1 [0.0–0.2]vs. 3.0 [0.6–7.7] colony-forming units (CFU)/ml, P < 0.01); and lamellar body concentration (0.0 [0.0–1.0]vs. 22.0 [18.5–29.5] thousands/&mgr;l, P < 0.01). No significant differences existed between the postfiltration and maternal samples for each of these parameters. Fetal hemoglobin was in higher concentrations in the postfiltration sample when compared with maternal blood (1.9 [1.1–2.5]vs. 0.5% [0.3–0.7] ). Potassium levels were significantly less in the postfiltration sample when compared with maternal (1.4 [1.0–1.5]vs. 3.8 mEq/l [3.7–4.0]). Conclusions Leukocyte depletion filtering of cell-salvaged blood obtained from cesarean section significantly reduces particulate contaminants to a concentration equivalent to maternal venous blood.

Topical tranexamic acid reduces blood loss and transfusion rates in total hip and total knee arthroplasty

The objective of this study was to determine if tranexamic acid (TXA) applied topically reduced postoperative bleeding and transfusion rates after primary total hip arthroplasty (THA) and primary total knee arthroplasty (TKA). Two hundred and ninety consecutive patients from a single surgeon were enrolled. In TKA, TXA solution was injected into the knee after closure of the arthrotomy. In THA, the joint was bathed in TXA solution at three points during the procedure. In both THA and TKA the TXA solution was at a concentration of 3 g TXA per 100 mL saline. The mean blood loss was significantly higher in the non-TXA patients in both TKA and THA groups. Postoperative transfusions decreased dramatically with TXA, dropping from 10% to 0%, and from 15% to 1%, in the TKA and THA groups, respectively. Topical application of TXA significantly reduces postoperative blood loss and transfusion risk in TKA and THA.

The AABB recommendations for the Choosing Wisely campaign of the American Board of Internal Medicine.

C hoosing Wisely is an initiative of the American Board of Internal Medicine Foundation designed to help physicians and patients engage in conversations to reduce overuse of tests and procedures and support physician efforts to help patients make smart and effective care choices. Blood transfusion is the commonest procedure performed in the hospitalized patient. Unnecessary use of blood transfusion in the hospitalized patient is common worldwide. Overuse of blood transfusion has also been listed as a Choosing Wisely statement by the American Society of Hematology, the Society of Hospital Medicine, and the Critical Care Societies Collaborative. To support this AABB Choosing Wisely initiative, the AABB developed a set of 10 recommendations with input from AABB committees and the AABB Board of Directors. This list was vetted by numerous AABB members to select the top five statements as required by the American Board of Internal Medicine. As required, all of these statements start with “Don’t.” The development of these statements and commentaries are intended to assist you with the promotion of better patient blood management at your local institution. These statements are intended to prompt non– transfusion medicine physicians to rethink their engrained culture of liberal transfusion practice and prompt patients to question why they are being prescribed blood. 1. Don’t transfuse more units of blood than absolutely necessary A restrictive threshold (7.0-8.0g/dL) should be used for the vast majority of hospitalized, stable patients without evidence of inadequate tissue oxygenation (evidence supports a threshold of 8.0g/dL in patients with existing cardiovascular disease). Transfusion decisions should be influenced by symptoms and hemoglobin (Hb) concentration. Singleunit red blood cell (RBC) transfusions should be the standard for nonbleeding hospitalized patients. Additional units should only be prescribed after reassessment of the patient and their Hb value. A total of 13.8 million units of whole blood and RBCs were transfused in the United States in 2011 equating to 44 units per 1000 population, which is considerably higher than in other developed countries such as Australia, Canada, the Netherlands, and the United Kingdom where the rates of RBC transfusion are at least 25% lower. In common with those countries, the use of RBC units is decreasing in the United States; the rate was 48.8 per 1000 population in 2008. In 2011, there were approximately 21 million blood components transfused in the United States. Each transfusion carries risks, although the number of transfusion-related fatalities reported to the US Food and Drug Administration (58 in 2013) and the number of transfusion-related adverse reactions reported to the National Blood Collection and Utilization Survey (51,000 in 2011) remain small in comparison to the total number of transfusions. There is considerable variation in the use of blood between countries, hospitals, and even clinical teams within the same hospital. This observation has been documented over many years and in several clinical settings and probably indicates that a substantial amount of blood is being transfused inappropriately. The precise reasons for this variation are uncertain, but they include lack of knowledge about the evidence for the restrictive use of blood and inadequate feedback of comparative data on blood utilization. The number of published clinical practice guidelines for RBC transfusion including those on behalf of the AABB and the American College of Physicians attest to the interest in appropriate blood utilization. The guidelines generally acknowledge the necessity of considering ABBREVIATIONS: INR(s) = international normalized ratio(s); PCC(s) = prothrombin complex concentrate(s); RR = risk ratio.

Blood salvage and cancer surgery: a meta‐analysis of available studies

BACKGROUND: Intraoperative blood salvage (IBS) is a technique that is frequently used in major blood loss surgery. Classically, it is avoided during cancer surgery where a fear exists of entraining cancer cells into the shed blood. In this study, all reports of this practice were collected to determine if this fear is warranted.

Extracorporeal membrane oxygenation in the adult: a review of anticoagulation monitoring and transfusion.

Extracorporeal membrane oxygenation (ECMO) is a method of life support to maintain cardiopulmonary function. Its use as a medical application has increased since its inception to treat multiple conditions including acute respiratory distress syndrome, myocardial ischemia, cardiomyopathy, and septic shock. While complications including neurological and renal injury occur in patients on ECMO, bleeding and coagulopathy are most common. ECMO is associated with an inflammatory response promoting a hypercoagulable state, requiring anticoagulation to avoid thromboembolism originating in the nonendothelial surfaced circuit. However, excessive anticoagulation may result in bleeding complications including intracerebral hemorrhage. Monitoring anticoagulation for ECMO has its origins in cardiopulmonary bypass for cardiac surgery; however, there is no ideal level of anticoagulation, no standardized method to monitor anticoagulation, nor are all centers standardized on what is used for anticoagulation. Multiple blood products are used in an effort to decrease bleeding in the setting of anticoagulation, often in the setting of recent surgery, and this leads to significant increases in cost for patients on ECMO and transfusion-related complications. In this review article, we discuss the evolution of the various modalities of ECMO, indications, contraindications, and complications. Furthermore, we review the different strategies for anticoagulation and treatment of coagulopathy while on ECMO. Finally, we discuss the cost of ECMO and associated blood product transfusion.

Intra-operative cell salvage: a fresh look at the indications and contraindications

Numerous approaches are used to avoid transfusion of allogeneic blood. Primary methods include, but are not limited to, erythropoietin and iron supplementation, pre-operative autologous donation, acute normovolaemic haemodilution, haemoglobin-based blood substitutes and infusible oxygen-carrying fluids, and the use of cell salvage systems. While currently unavailable in North America and Europe because of an increased risk of myocardial infarction and death1,2, research continues in the areas of haemoglobin-based blood substitutes and infusible oxygen-carrying liquids. Of the accepted strategies mentioned above, cell salvage offers the medical community a safe, resource-saving, and relatively inexpensive method to avoid allogeneic red cell transfusion. Currently, incorrect information and misconceptions regarding the use of cell salvage systems frequently portray them as expensive, ineffective, and inappropriate for use in certain clinical situations. In addition to addressing these misconceptions, this article will discuss indications and contraindications for the use of such systems.

Transfusion reactions: prevention, diagnosis, and treatment

Blood transfusion is one of the most common procedures in patients in hospital so it is imperative that clinicians are knowledgeable about appropriate blood product administration, as well as the signs, symptoms, and management of transfusion reactions. In this Review, we, an international panel, provide a synopsis of the pathophysiology, treatment, and management of each diagnostic category of transfusion reaction using evidence-based recommendations whenever available.