Role of anesthesiologists in managing perioperative anemia.

PURPOSE OF REVIEW: Anemia can contribute negatively to a patient's morbidity and mortality. Which treatment options do exist and what role do anesthesiologists play in management of perioperative anemia treatment? This review gives an overview about recent findings. RECENT FINDINGS: Patient Blood Management and standards for the management and treatment of anemia have been established worldwide. Various logistic settings and approaches are possible. With a special focus on cardiovascular anesthesia, intravenous iron is a therapeutic option in the preoperative setting. Autologous blood salvage is a standard procedure during surgery. Restrictive transfusion triggers in adult cardiac surgery have been shown to be beneficial in the majority of studies. Elderly patients and defined comorbidities might require higher transfusion triggers. Both, intravenous and oral iron increase hemoglobin values when given prior to surgery. Oral iron is effective when given several weeks prior to elective surgery. Erythropoietin is a treatment decision individualized to each patient. SUMMARY: Within the previous 18 months, important publications have demonstrated the established role of anesthesiologists in managing perioperative anemia. A substantial pillar for anemia treatment is the implementation of Patient Blood Management worldwide.

Treating Anemia in the Preanesthesia Assessment Clinic: Results of a Retrospective Evaluation.

BACKGROUND: Perioperative anemia is challenging during hospital stay because anemia and red blood cell (RBC) transfusions are associated with an increased morbidity and mortality. With the implementation of patient blood management (PBM), a preanesthesia assessment clinic to screen and treat anemia before elective surgery was institutionalized at Muenster University Hospital, Germany. The main objective of this study was to evaluate the association between treating preoperative anemic patients with intravenous iron (IVI) and (primarily) presurgical hemoglobin levels and (secondarily) use of RBCs and mortality. METHODS: Between April 1, 2014, and July 4, 2016, patients scheduled for elective surgery with a risk for RBC transfusions >10% in 2013 were screened for preoperative anemia and, if indicated, treated with IVI. Patients' data, time span between visit in the anesthesia/PBM clinic and surgery, demographic data, type of surgery, the difference of hemoglobin levels between visit and surgery, RBC transfusion, infectious-related International Classification of Disease codes during hospital stay, and 1-year survival were determined retrospectively by screening electronic data files. In addition, patients were interviewed about adverse events, health-related events, and infections via telephone 30, 90, and 365 days after visiting the anesthesia/PBM clinic. RESULTS: A total of 1101 patients were seen in the anesthesia/PBM clinic between days -28 and -1 (median [Q1-Q3], -3 days [-1, -9 days]) before elective surgery. Approximately 29% of patients presented with anemia, 46.8% of these anemic patients were treated with ferric carboxymaltose (500-1000 mg).In the primary analysis, hemoglobin levels at median were associated with a reduction between the visit in the anesthesia/PBM clinic and the surgery in all nonanemic patients on beginning of medical treatment (nonanemic patients at median -2.8 g/dL [-4, -0.9 g/dL], while anemic patients without IVI presented with median differences of -0.8 g/dL [-2, 0 g/dL] and anemic patients with IVI of 0 g/dL [-1.0, 0.5 g/dL]). Hemoglobin levels raised best at substitution 22-28 days before surgery (0.95 g/dL [-0.35, 1.18 g/dL]). Due to the selection criteria, transfusion rates were high in the cohort. Overall, there was no association between IVI treatment and the use of RBC transfusions (odds ratio for use of RBCs in anemic patients, no IVI versus IVI: 1.14; 95% confidence interval, 0.72-1.82). Patients treated with or without IVI presented a comparable range of International Classification of Disease codes related to infections. Telephone interviews indicated similar adverse events, health-related events, and infections. Cox regression analysis showed an association between anemia and reduced survival, regardless of IVI. CONCLUSIONS: An anemia clinic within the preanesthesia assessment clinic is a feasible and effective approach to treat preoperative anemia. The IVI supplementation was safe but was associated with decreased RBC transfusions in gynecology/obstetric patients only. The conclusions from this retrospective analysis have to be tested in prospective, controlled trials.

Post-Operative Iron Carboxymaltose May Have an Effect on Haemoglobin Levels in Cardiothoracic Surgical Patients on the ICU - an Observational Pilot Study about Anaemia Treatment with Intravenous Iron.

BACKGROUND: Post-operative anaemia is associated with increased morbidity and mortality. Positive effects of post-operative intravenous iron (IVI) after elective orthopaedic, abdominal and genitourinary surgery have been reported. The current observational trial investigated the prevalence of post-operative anaemia, the effect of IVI on haemoglobin levels, the use of blood transfusions and diagnoses related to infections. METHODS: 1,265 patients on five ICUs of Münster University Hospital were screened for post-operative anaemia. On one ICU, patients were screened for iron deficiency and, if indicated, supplemented with 500 mg of ferric carboxymaltose. Primary outcome measures were haemoglobin levels, C-reactive protein, white blood cell count, transfusion requirements, documented infection and antibiotic treatment. RESULTS: Anaemia was prevalent in 86.2% of patients upon ICU admission. 429 patients were screened for iron deficiency anaemia. 95 patients were eligible, 35 were treated with IVI. An increase of +0.4 g/dl in Hb levels 7 days after IVI compared to -0.1 g/dl in non-treated anaemic patients was observed. The number of RBC transfusions, ICD codes related to infections and infectious parameters were similar between groups. Conclusions: IVI treatment was safe and resulted in higher median Hb levels. Randomized controlled trials are required to support the hypotheses of this study.

Intravenous Iron Carboxymaltose as a Potential Therapeutic in Anemia of Inflammation.

Intravenous iron supplementation is an effective therapy in iron deficiency anemia (IDA), but controversial in anemia of inflammation (AI). Unbound iron can be used by bacteria and viruses for their replication and enhance the inflammatory response. Nowadays available high molecular weight iron complexes for intravenous iron substitution, such as ferric carboxymaltose, might be useful in AI, as these pharmaceuticals deliver low doses of free iron over a prolonged period of time. We tested the effects of intravenous iron carboxymaltose in murine AI: Wild-type mice were exposed to the heat-killed Brucella abortus (BA) model and treated with or without high molecular weight intravenous iron. 4h after BA injection followed by 2h after intravenous iron treatment, inflammatory cytokines were upregulated by BA, but not enhanced by iron treatment. In long term experiments, mice were fed a regular or an iron deficient diet and then treated with intravenous iron or saline 14 days after BA injection. Iron treatment in mice with BA-induced AI was effective 24h after iron administration. In contrast, mice with IDA (on iron deficiency diet) prior to BA-IA required 7d to recover from AI. In these experiments, inflammatory markers were not further induced in iron-treated compared to vehicle-treated BA-injected mice. These results demonstrate that intravenous iron supplementation effectively treated the murine BA-induced AI without further enhancement of the inflammatory response. Studies in humans have to reveal treatment options for AI in patients.

Out of balance--systemic iron homeostasis in iron-related disorders.

Iron is an essential element in our daily diet. Most iron is required for the de novo synthesis of red blood cells, where it plays a critical role in oxygen binding to hemoglobin. Thus, iron deficiency causes anemia, a major public health burden worldwide. On the other extreme, iron accumulation in critical organs such as liver, heart, and pancreas causes organ dysfunction due to the generation of oxidative stress. Therefore, systemic iron levels must be tightly balanced. Here we focus on the regulatory role of the hepcidin/ferroportin circuitry as the major regulator of systemic iron homeostasis. We discuss how regulatory cues (e.g., iron, inflammation, or hypoxia) affect the hepcidin response and how impairment of the hepcidin/ferroportin regulatory system causes disorders of iron metabolism.

Transfusion of stored autologous blood does not alter reactive hyperemia index in healthy volunteers.

BACKGROUND: Transfusion of human blood stored for more than 2 weeks is associated with increased mortality and morbidity. During storage, packed erythrocytes progressively release hemoglobin, which avidly binds nitric oxide. We hypothesized that the nitric oxide mediated hyperemic response after ischemia would be reduced after transfusion of packed erythrocytes stored for 40 days. METHODS AND RESULTS: We conducted a crossover randomized interventional study, enrolling 10 healthy adults. Nine volunteers completed the study. Each volunteer received one unit of 40-day and one of 3-day stored autologous leukoreduced packed erythrocytes, on different study days according to a randomization scheme. Blood withdrawal and reactive hyperemia index measurements were performed before and 10 min, 1 h, 2 h, and 4 h after transfusion. The reactive hyperemia index during the first 4 h after transfusion of 40-day compared with 3-day stored packed erythrocytes was unchanged. Plasma hemoglobin and bilirubin concentrations were higher after transfusion of 40-day than after 3-day stored packed erythrocytes (P = 0.02, [95% CI difference 10-114 mg/l] and 0.001, [95% CI difference 0.6-1.5 mg/dl], respectively). Plasma concentrations of potassium, lactate dehydrogenase, haptoglobin, and cytokines, as well as blood pressure, did not differ between the two transfusions and remained within the normal range. Plasma nitrite concentrations increased after transfusion of 40-day stored packed erythrocytes, but not after transfusion of 3-day stored packed erythrocytes (P = 0.01, [95% CI difference 0.446-0.66 µM]). CONCLUSIONS: Transfusion of autologous packed erythrocytes stored for 40 days is associated with increased hemolysis, an unchanged reactive hyperemia index, and increased concentrations of plasma nitrite.

Pulmonary hypertension in lambs transfused with stored blood is prevented by breathing nitric oxide.

BACKGROUND: During extended storage, erythrocytes undergo functional changes. These changes reduce the viability of erythrocytes leading to release of oxyhemoglobin, a potent scavenger of nitric oxide. We hypothesized that transfusion of ovine packed erythrocytes (PRBC) stored for prolonged periods would induce pulmonary vasoconstriction in lambs, and that reduced vascular nitric oxide concentrations would increase this vasoconstrictor effect. METHODS: We developed a model of autologous stored blood transfusion in lambs (n = 36). Leukoreduced blood was stored for either 2 days (fresh PRBC) or 40 days (stored PRBC). Fresh or stored PRBC were transfused into donors instrumented for awake hemodynamic measurements. Hemodynamic effects of PRBC transfusion were also studied after infusion of N-nitro-L-arginine methyl-ester (25 mg/kg) or during inhalation of nitric oxide (80 ppm). RESULTS: Cell-free hemoglobin levels were higher in the supernatant of stored PRBC than in supernatant of fresh PRBC (Mean ± SD, 148 ± 20 vs. 41 ± 13 mg/dl, respectively, P < 0.001). Pulmonary artery pressure during transfusion of stored PRBC transiently increased from 13 ± 1 to 18 ± 1 mmHg (P < 0.001) and was associated with increased plasma hemoglobin concentrations. N-nitro-L-arginine methyl-ester potentiated the increase in pulmonary arterial pressure induced by transfusing stored PRBC, whereas inhalation of nitric oxide prevented the vasoconstrictor response. CONCLUSIONS: Our results suggest that patients with reduced vascular nitric oxide levels because of endothelial dysfunction may be more susceptible to adverse effects of transfusing blood stored for prolonged periods. These patients might benefit from transfusion of fresh PRBC, when available, or inhaled nitric oxide supplementation to prevent the pulmonary hypertension associated with transfusion of stored PRBC.