[Impact of acute normovolemic hemodilution on primary hemostasis]. / Einfluss der akuten normovolämischen Hämodilution auf die primäre Hämostase.

BACKGROUND: Acute normovolemic hemodilution (ANH) is performed with the intention to reduce the requirement for allogeneic blood transfusions. After preoperative withdrawal of whole blood, corresponding amounts of crystalloids and/or colloids are infused to maintain normovolemia. The main benefit of ANH is the availability of whole blood containing red blood cells, clotting factors and platelets for reinfusion after removal during the dilution process. Until retransfusion whole blood components are stored at the patient's bedside in the operating theatre. AIM: It was the aim of the present investigation to analyze potential changes in ex vivo induced platelet aggregation in stored blood components. MATERIAL AND METHODS: After obtaining approval 15 patients undergoing complex cardiac surgery were enrolled into this prospective observational study. Acute normovolemic hemodilution (ANH) was routinely performed in this collective based on institutional standards. Besides analyses of pH and plasma concentrations of ionized calcium and hemoglobin, hematological analyses included aggregometric measurements using multiple electrode aggregometry (MEA, Multiplate®, Roche, Grenzach, Germany). Ex vivo platelet aggregation was induced using arachidonic acid (ASPI test), as well as thrombin receptor activating peptide (TRAP test) and adenosine diphosphate (ADP test). Laboratory analyses were performed before beginning ANH (baseline), as well as immediately (T1), 30 min (T2), 60 min (T3), 90 min (T4), 120 min (T5), 150 min (T6) and 180 min (T7) after beginning of storage. The areas under the aggregation curves (AUC) in the MEA were defined as primary (ASPI test) and secondary endpoints (ADP test, TRAP test). RESULTS: As compared to baseline, arachidonic acid induced platelet aggregation was significantly reduced at T1 [77 U (68/94 U) vs. 53 U (25/86 U), p = 0.003] and each consecutive measuring point. As compared to T1 (begin of storage), arachidonic acid induced platelet aggregation was significantly reduced at T4 [26 U (14/54 U); p = 0.002], T5 [30 U (21/36 U); p = 0.007], T6 [25 U (17/40 U); p = 0.004] and T7 [28 U (17/39 U); p < 0.001]. The extent of ex vivo induced platelet aggregation in the TRAP test and ADP test remained unchanged during the study period. The pH as well as the concentrations of ionized calcium and hemoglobin remained unchanged in the blood component during storage. CONCLUSION: The results of the present study indicate that disturbances of platelet aggregation may occur during storage of whole blood components prepared for the purpose of ANH. Further investigations are needed to analyze whether the observed phenomena are of hemostatic relevance.

[Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]. / Perioperative Anämietoleranz. Mechanismen, Einflussfaktoren, Grenzen.

The expected cost explosion in transfusion medicine increases the socio-economic significance of specific institutional transfusion programs. In this context the estimated use of the patient's physiologic tolerance represents an integral part of any blood conservation concept. The present article summarizes the mechanisms, influencing factors and limits of this natural tolerance to anemia and deduces the indication for perioperative red blood cell transfusion. The current recommendations coincide to the effect that perioperative transfusion is unnecessary up to a Hb concentration of 10 g/dl (6.21 mmol/l) even in older patients with cardiopulmonary comorbidity and is only recommended in cases of Hb <6 g/dl (<3.72 mmol/l) in otherwise healthy subjects including pregnant women and children. Critically ill patients with multiple trauma and sepsis do not seem to benefit from transfusions up to Hb concentrations >9 g/dl (>5.59 mmol/l). In cases of massive hemorrhaging and diffuse bleeding disorders the maintenance of a Hb concentration of 10 g/dl (6.21 mmol/l) seems to contribute to stabilization of coagulation.

Effects of standardized acute normovolemic hemodilution on intraoperative allogeneic blood transfusion in patients undergoing major maxillofacial surgery.

The aim of the present study was to demonstrate the practicality and efficacy of acute normovolemic hemodilution (ANH) to reduce allogeneic red blood cell (RBC) transfusion in patients undergoing elective surgery with anticipated high intraoperative blood loss (BL). 124 patients (age 48 +/- 18 years, ASA classes I-III) underwent major maxillofacial surgery in a university hospital (68% tumor surgery, 32% dysgnathia correction). After induction of general anesthesia, ANH was performed by standardized withdrawal of 900 ml (2 units) of whole blood and simultaneous infusion of 500 ml of hydroxyethyl starch solution (6% HES 130,000/0.4) and 1500 ml of crystalloidal solution. Intraoperative BL was fluid-compensated until physiologic parameters indicated the need for RBC transfusion. First, autologous ANH-blood was retransfused followed by, if necessary, allogeneic RBC. Total BL was referred to the patient's calculated blood volume (BV): fractional blood volume loss, BL(fract) = BL/BV. ANH took 16 +/- 2 min and was void of any adverse event. The costs for ANH was 24 per patient. 55 patients had a mean BL(fract) of 44 +/- 28% and required an intraoperative transfusion; 49/55 patients with an average BL(fract) of 37 +/- 14% were transfused with only autologous ANH-blood; 6/55 patients with a mean BL(fract) of 100 +/- 47% underwent additional transfusion with allogeneic RBC. Standardized, 2 unit, ANH is a practicable, safe and economic blood conservation technique that allowed for the complete avoidance of allogeneic RBC transfusion in 89% of patients undergoing maxillofacial surgery that required an intraoperative RBC transfusion.

[Indications for blood transfusion during orthopedic surgery]. / Indikation zur Bluttransfusion bei orthopädischen Eingriffen.

Ageing of the population increases the number of large orthopedic surgical interventions in elder people. High perioperative blood loss together with a reduced tolerance to anemia increase the transfusion probability in this patient subgroup. The expected cost explosion in the transfusion system (cost intensive quality management, imbalance between the number of donors and recipients) as well as the remaining transfusion related risk of hemolysis, infection and immunosuppression reflect the high socio-economic significance of the development of institutional transfusion programs. The present article summarizes: (1) the (patho-) physiology of anemia compensation, (2) the decision making for transfusion in healthy patients and patients with cardiovascular disease, and (3) the currently applied pre- and intraoperative techniques to reduce allogeneic transfusion in orthopedic patients.

[Bacterial pathogens, resistance patterns and treatment options in community acquired pediatric urinary tract infection]. / Bakterielle Erreger, Resistenzentwicklung und Behandlungsoptionen beim ambulant erworbenen Harnwegsinfekt im Kindesalter.

BACKGROUND: Epidemiology and resistance patterns of bacterial pathogens in pediatric UTI show large interregional variability and rates of bacterial resistances are changing due to different antibiotic treatment. We intended to evaluate data from northern Germany. PATIENTS AND METHODS: In 100 children (53 female, 47 male, mean age 4.4 +/- 4.2 years) with community acquired UTI, who presented in the emergency department of our medical school from 2000 - 2002, urine cultures were performed. Inclusion criteria were: acute voiding symptoms, significant bacteriuria with growth of at least 10 (5) colony-forming units/ml urine, leukocyturia > 50/ micro l. Exclusion criteria were underlying renal diseases, anatomic abnormalities of the urinary tract, age < 2 months and recurrent UTI. RESULTS: Patients presented with a mean rectal temperature of 38.6 +/- 1.3 degrees C, mean CRP of 66 +/- 68 mg/dl, mean WBC 13 500 +/- 5 600/ micro l and mean urinary leukocytes of 425 +/- 363/ micro l. In urine cultures E. coli was found in 47 % of the cases, Enterococcus faecalis 23 %, Proteus mirabilis 8 %, Klebsiella oxytoca 4 %, Pseudomonas aeruginosa 5 % and others 13 %. In 76 % one and in 24 % two different bacterial species (60 % Enterococcus faecalis) were cultured. Mean resistance rates were in all bacteria (in E. coli): Ampicillin 53 % (69 %), Ampicillin and Sulbactam 51 % (61 %), Cefalosporin 1 (st) generation (Cefaclor) 48 % (24 %), Cefalosporin 2 (nd) generation (Cefuroxim) 40 % (3 %), Cefalosporin 3 (rd) generation (Cefuroxim) 33 % (0 %), Tobramycin 30 % (2 %), Ciprofloxacine 0 %, Cotrimoxazole 40 % (42 %), Nitrofurantoin 12 % (0 %). CONCLUSION: The resistance rates to Ampicillin (+/- Sulbactam) did not increase as compared to previous analyses (1990 - 1995), however, resistance rates to Cotrimoxazole and 1 (st) generation Cefalosporines increased about 20 %. We conclude that the policies for treatment of UTI in children should be re-evaluated every 5 years according to local resistance rates.

Influence of technetium-99m-labeling conditions on physico-chemical and related biological properties of an acylated poly-galactosidic macrophage targeting agent for inflammation imaging.

The potential of 99m-Tc-J001 for the investigation of inflammatory lesions via the targeting of recruited macrophages (M phi) has already been documented in several experimental models and in human diseases. To achieve a functional imaging of inflammation via M phi targeting, minimal labeled colloid content and high in vivo stability of 99mTc-J001 are essential. The actual specificity of such scintigraphy is closely dependent upon the radiolabeling of only the J001 molecules available for M phi targeting. To develop an appropriate radiopharmaceutical kit, optimization of the labeling conditions was achieved from a series of pilot formulations that were evaluated for radiolabeling efficiency and both in vitro and in vivo 99mTc-J001 stability. Colloids were characterized using autocorrelation spectroscopy and multiangle laser-light scattering, radioactive colloid content of the formulations being deduced from biodistribution studies. This work has made possible the definition of a formulation exhibiting a radiolabeling yield > 97.0%, associated with in vivo stability and minimal colloid formation, thus greatly enhancing the specificity of such macrophage scintigraphy.

Biochemical events occurring during the respiratory burst of macrophages: A 31P and 13C NMR study.

In a previous study, 31P NMR revealed that an intracellular acidification occurred during the respiratory burst of P388 D1 macrophages, but this NMR technique could not provide information about the localization of this event in cells. However, using a fluorescent pH-dependent probe, it was confirmed that this transient pH decrease does not occur in the cytosol but more probably occurs in relation to the function of endocytic vesicles. A 31P NMR study allowed us to evidence a transient increase in ADP phosphorylation at the beginning of the respiratory burst, possibly in connection with the initiation of the oxidase complex involved in superoxide anion production. A 13C NMR study of perchloric acid extracts from in vivo primed cells revealed an increase in glucose consumption due to Con A triggering. Sugar phosphates, which must be considered markers of the hexose monophosphate shunt involved in the respiratory burst, were also observed upon this activation process.