[Working in the magnetic field of ultrahigh field MRI]. / Arbeiten im Magnetfeld von Ultrahochfeld-MRT.

Development of magnetic resonance imaging (MRI) device technology continues to increase the static magnetic flux densities applied and consequently leads to considerably increased occupational exposure. This has already made it necessary to review limits of occupational exposure and to postpone European legal regulations for occupational exposure to electromagnetic fields. This raises the question whether and if so which adverse health effects and health risks might be associated with occupational exposure to MRI ultra-high static magnetic fields. Based on a survey on interaction mechanisms recommendations and safety rules are presented to help minimize adverse health effects of emerging ultra-high field MRI.

[Patient Blood Management : three pillar strategy to improve outcome through avoidance of allogeneic blood products]. / Patient Blood Management : Dreisäulenstrategie zur Verbesserung des Outcome durch Vermeidung allogener Blutprodukte.

Blood transfusions are commonly viewed as life-saving interventions; however, current evidence shows that blood transfusions are associated with a significant increase of morbidity and mortality in a dose-dependent relationship. Not only explanatory models of basic research but also the results from randomized controlled trials suggest a causal relationship between blood transfusion and adverse outcome. Therefore, it can be claimed that the current state of science debunks the long held belief in the so-called life-saving blood transfusion by exposing the potential for promoting disease and death. Adherence to the precautionary principle and also the fact that blood transfusions are more costly than previously assumed require novel approaches in the treatment of anemia and bleeding. Patient Blood Management (PBM) allows transfusion rates to be dramatically reduced through correcting anemia by stimulating erythropoiesis, minimization of perioperative blood loss and harnessing and optimizing the physiological tolerance of anemia. A resolution of the World Health Assembly has endorsed PBM and therefore morbidity and mortality should be significantly reduced by lowering of the currently high blood utilization rate of allogeneic blood products in Austria, Germany and Switzerland.

Patient blood management in Europe.

Preoperative anaemia is common in patients undergoing orthopaedic and other major surgery. Anaemia is associated with increased risks of postoperative mortality and morbidity, infectious complications, prolonged hospitalization, and a greater likelihood of allogeneic red blood cell (RBC) transfusion. Evidence of the clinical and economic disadvantages of RBC transfusion in treating perioperative anaemia has prompted recommendations for its restriction and a growing interest in approaches that rely on patients' own (rather than donor) blood. These approaches are collectively termed 'patient blood management' (PBM). PBM involves the use of multidisciplinary, multimodal, individualized strategies to minimize RBC transfusion with the ultimate goal of improving patient outcomes. PBM relies on approaches (pillars) that detect and treat perioperative anaemia and reduce surgical blood loss and perioperative coagulopathy to harness and optimize physiological tolerance of anaemia. After the recent resolution 63.12 of the World Health Assembly, the implementation of PBM is encouraged in all WHO member states. This new standard of care is now established in some centres in the USA and Austria, in Western Australia, and nationally in the Netherlands. However, there is a pressing need for European healthcare providers to integrate PBM strategies into routine care for patients undergoing orthopaedic and other types of surgery in order to reduce the use of unnecessary transfusions and improve the quality of care. After reviewing current PBM practices in Europe, this article offers recommendations supporting its wider implementation, focusing on anaemia management, the first of the three pillars of PBM.

[Working in the magnetic field of ultrahigh field MRI]. / Arbeiten im Magnetfeld von Ultrahochfeld-MRT.

Development of magnetic resonance imaging (MRI) device technology continues to increase the static magnetic flux densities applied and consequently leads to considerably increased occupational exposure. This has already made it necessary to review limits of occupational exposure and to postpone European legal regulations for occupational exposure to electromagnetic fields. This raises the question whether and if so which adverse health effects and health risks might be associated with occupational exposure to MRI ultra-high static magnetic fields. Based on a survey on interaction mechanisms recommendations and safety rules are presented to help minimize adverse health effects of emerging ultra-high field MRI.

[Life-threatening opioid overdose. Decoding the physician pin code of a patient-controlled anesthesia pump by patients]. / Lebensbedrohliche Opioidüberdosierung. Entschlüsselung des Arztboluscodes einer Schmerzpumpe durch Patienten.

Patient-controlled analgesia (PCA) is an established standard therapy for providing postoperative analgesia. To avoid possible abuse by patients each PCA pump is secured by a pin code that should be neither known nor accessible to patients. The two case reports described illustrate how manipulation of a PCA pump led to massive opioid abuse by the patients who decoded the pin code for unlimited additional doses. One patient developed withdrawal symptoms after switching the therapy and, as a consequence even had to be admitted to the intensive care unit (ICU). Easy access to the PCA pump codes on the internet for the patients and the impossibility of changing the pin codes by the medical staff played an important role in these two cases.

Point-of-care assessment of platelet aggregation in paediatric open heart surgery.

BACKGROUND: Congenital heart disease (CHD) is associated with complex coagulation abnormalities. Platelet aggregability has not been investigated in detail in children with acyanotic and cyanotic malformations undergoing open heart surgery. The method of whole-blood multiple electrode aggregometry (MEA) appears suitable for rapid platelet analysis in children, for example, because of small sample volumes. We investigated perioperative evolution of platelet aggregation by means of MEA in children with CHD. METHODS: Fifty children with acyanotic or cyanotic malformations were included in a prospective observational study. Laboratory testing was assessed before anaesthesia, and during and after surgery until the fifth postoperative day. MEA was performed in hirudin-anticoagulated blood using adenosine diphosphate (ADP), arachidonic acid, and thrombin receptor-activating peptide for platelet activation. Surgical variables, bleeding volumes, and transfusion requirements were documented during hospital stay. RESULTS: Mean platelet count was within the normal range in all patients with no intergroup differences. Before surgery, aggregation to all agonists was within the age-adjusted normal range in cyanotic children and was statistically significantly higher compared with acyanotic children. Platelet aggregation decreased significantly during surgery in both groups followed by a slow recovery not reaching baseline levels. Bleeding and platelet transfusions were higher in the cyanotic group. Transfusion requirements correlated with ADP-induced platelet aggregation. CONCLUSIONS: These results indicate higher blood loss, despite better platelet aggregation in cyanotic patients compared with acyanotic patients. MEA alone might not be suitable for predicting increased perioperative blood loss.

Detection, evaluation, and management of preoperative anaemia in the elective orthopaedic surgical patient: NATA guidelines.

Previously undiagnosed anaemia is common in elective orthopaedic surgical patients and is associated with increased likelihood of blood transfusion and increased perioperative morbidity and mortality. A standardized approach for the detection, evaluation, and management of anaemia in this setting has been identified as an unmet medical need. A multidisciplinary panel of physicians was convened by the Network for Advancement of Transfusion Alternatives (NATA) with the aim of developing practice guidelines for the detection, evaluation, and management of preoperative anaemia in elective orthopaedic surgery. A systematic literature review and critical evaluation of the evidence was performed, and recommendations were formulated according to the method proposed by the Grades of Recommendation Assessment, Development and Evaluation (GRADE) Working Group. We recommend that elective orthopaedic surgical patients have a haemoglobin (Hb) level determination 28 days before the scheduled surgical procedure if possible (Grade 1C). We suggest that the patient's target Hb before elective surgery be within the normal range, according to the World Health Organization criteria (Grade 2C). We recommend further laboratory testing to evaluate anaemia for nutritional deficiencies, chronic renal insufficiency, and/or chronic inflammatory disease (Grade 1C). We recommend that nutritional deficiencies be treated (Grade 1C). We suggest that erythropoiesis-stimulating agents be used for anaemic patients in whom nutritional deficiencies have been ruled out, corrected, or both (Grade 2A). Anaemia should be viewed as a serious and treatable medical condition, rather than simply an abnormal laboratory value. Implementation of anaemia management in the elective orthopaedic surgery setting will improve patient outcomes.

[Preoperative anemia in orthopedic surgery: clinical impact, diagnostics and treatment]. / Präoperative Anämie in der Orthopädie: Klinische Relevanz, Diagnostik und Therapie.

In a national audit of elective orthopedic surgery conducted in the US, 30% of patients were found to have hemoglobin (Hgb) levels < 13 g/dl at preadmission testing. Preoperative anemia has been associated with increased mortality and morbidity after surgery, increased allogeneic blood transfusion therapy and increased rates of postoperative infection leading to a longer length of hospital stay. Because of the risks associated with allogeneic blood transfusions according to German law patients have to be offered the option of autologous transfusion if the risk associated with allogeneic blood transfusion is > 10%. However, one of these measures, the autologous blood donation, can exaggerate anemia and can increase the overall transfusion rates (allogeneic and autologous). As autologous procedures (autologous blood donation and cell salvage) are not always appropriate for anemic patients together with an expected shortage of blood and because preoperative anemia is associated with perioperative risks of blood transfusion, a standardized approach for the detection, evaluation and management of anemia in this setting was identified as an unmet medical need. A panel of multidisciplinary physicians was convened by the Society for Blood Management to develop a clinical care pathway for anemia management in elective surgery patients for whom blood transfusion is an option. In these guidelines elective surgery patients should have Hgb level determination at the latest 28 days before the scheduled surgical procedure. The patient target Hgb before elective surgery should be within the normal range (normal female ≥ 120 g/l, normal male ≥ 130 g/l). Laboratory testing should take place to further determine nutritional deficiencies, chronic renal insufficiency and/or chronic inflammatory diseases. Nutritional deficiencies should be treated and erythropoiesis-stimulating agent (ESA) therapy should be used for anemic patients in whom nutritional deficiencies have been ruled out and/or corrected.

[Perioperative management of patients with implanted pacemakers or cardioverter/defibrillators. Recommendations of the Austrian Society for Anaesthesiology, Resuscitation and Intensive Care Medicine, the Austrian Society for Cardiology and the Austrian Society for Surgery]. / Perioperatives Management von Patienten mit implantiertem Schrittmacher oder Kardioverter/Defibrillator. Empfehlungen der Osterreichischen Gesellschaft für Anästhesiologie, Reanimation und Intensivmedizin, der Osterreichischen Kardiologischen Gesellschaft und der Osterreichischen Gesellschaft für Chirurgie.

The perioperative risk for patients with pacemakers or implanted cardioverter/defibrillators (ICD) is mainly dependent on the underlying disease. However, severe to life-threatening complications of the implanted system can occur due to electromagnetic interference in the environment of the operation. These complications can be prevented or adequately treated by taking special precautions and measures. Even though the currently available data on the optimal perioperative management to pacemakers and ICDs is still unsatisfactory, the increasing clinical relevance of this topic was the reason for the formulation of recommendations by an interdisciplinary working group in Austria.

Patient blood management: A solution for South Africa.

For more than 70 years the default therapy for anaemia and blood loss was mostly transfusion. Accumulating evidence demonstrates a significant dose-dependent relationship between transfusion and adverse outcomes. This and other transfusion-related challenges led the way to a new paradigm. Patient blood management (PBM) is the application of evidence-based practices to optimise patient outcomes by managing and preserving the patient's own blood. 'Real-world' studies have shown that PBM improves patient outcomes and saves money. The prevalence of anaemia in adult South Africans is 31% in females and 17% in males. Improving the management of anaemia will firstly improve public health, secondly relieve the pressure on the blood supply, and thirdly improve the productivity of the nation's workforce. While high-income countries are increasingly implementing PBM, many middle- and low-income countries are still trying to upscale their transfusion services. The implementation of PBM will improve South Africa's health status while saving costs.

In-hospital cardiac resuscitation outside the ICU by nursing staff equipped with automated external defibrillators--the first 500 cases.

BACKGROUND: Since nursing staff in the hospital are frequently the first to witness a cardiac arrest, they may play a central role in the effective management of in-hospital cardiac arrest. In this retrospective study the first 500 in-hospital cardiac arrests in non-monitored areas, which were treated initially by nursing staff equipped with automated external defibrillators (AEDs) are reported. METHODS AND RESULTS: Between April 2001 and December 2004, 500 in-hospital cardiac arrest calls were made: there were false arrests in 61 patients, so a total of 439 patients (88%) were evaluated using the Utstein style of data collection. ROSC occurred in 256 patients (58%), 125 (28%) were discharged from hospital and 95 (22%) were still alive 6 months after discharge. Among the 73 patients with VF/VT 63 (86%) had ROSC, 34 (47%) were discharged from hospital and 28 (38%) were alive after 6 months. The chance of survival was not influenced by the time between the call of the arrest team and the 1st defibrillation but was slightly higher with physicians as in-hospital first responders (p=0.078). In contrast, 366 patients with non-VF/VT, 193 (53%) had ROSC, but only 91 (25%) were discharged from hospital and 67 (18%) were alive after 6 months. The risk of dying was significantly higher in patients with non-VF/VT (p<0.001), and there was a trend to a higher risk ratio in patients older than 65 years and in patients with non-witnessed cardiac arrest (p=0.056 and 0.079, respectively). CONCLUSION: This observational study supports the concept of hospital-wide first responder resuscitation performed by nursing staff before the arrival of the CPR-team. Among these patients survival rate was higher in those with VF/VT defibrillated at an early stage. Consequently, it may be assumed that patients may die unnecessarily due to sudden cardiac arrest if proper in-hospital resuscitation programmes are not available.

Subcutaneous epoetin alfa as an adjunct to autologous blood donation before elective coronary artery bypass graft surgery.

Autologous blood (AB) donation can minimize exposure to allogeneic blood in patients scheduled for coronary artery bypass graft (CABG) surgery. During AB donation in this group of patients, minimization of the accompanying decrease in hemoglobin (Hb) levels is important to reduce the risk of provoking silent myocardial ischemia and/or arrhythmias. Recombinant human erythropoietin (rHuEPO) has been used to facilitate AB donation and minimize the accompanying decrease in Hb levels in patients scheduled for cardiac surgery. In 24 patients scheduled for CABG surgery, once-weekly subcutaneous (s.c.) administration of rHuEPO (epoetin alfa 400 IU/kg) plus oral iron supplementation for 4 weeks prior to surgery caused marked stimulation of erythropoiesis and significantly increased collection of autologous red blood cells (RBCs) compared with oral iron alone. Furthermore, epoetin alfa minimized the decrease in Hb levels associated with AB donation and significantly attenuated allogeneic blood requirements by facilitating the collection of 4 AB units prior to surgery. During AB donation, no changes in the incidence or severity of ischemic attacks or ST-segment changes were observed using electrocardiographic monitoring. Epoetin alfa was well tolerated. Once-weekly s.c. administration of epoetin alfa for 4 weeks therefore represents a practical means of facilitating AB donation by patients scheduled for CABG surgery.

Neuromonitoring during hypothermic cardiopulmonary bypass.

To reduce the incidence of neurological and neuropsychological dysfunction following hypothermic cardiopulmonary bypass (CPB), central nervous system (CNS) monitoring before, during, and after CPB seems to be necessary. Compared to the total scope of hemodynamic monitoring CNS monitoring, however, is mostly investigational and infrequently used in clinical routine, and the impact on postoperative outcome is still being discussed. An optimal CNS monitoring would have to include continuous objective measurement of brain function, perfusion, and metabolism with regard to patients' disease and would also have to be adapted to the technique applied and the period of CPB. Over the past few years a number of monitoring devices (computer-processed electroencephalogram, jugular bulb saturation, Doppler flow measurement, near infrared spectroscopy) have been evaluated. Each of them has a specific diagnostic power so that a combination of only two or more devices will meet the criteria for effective brain monitoring. In addition, the impact on outcome and the applicability and cost-effectiveness of these tools will have to be investigated in the future.

[Open heart surgery in Jehovah's Witnesses]. / Offene Herzoperationen bei Zeugen Jehovas.

Patients who are Jehovah's Witnesses present a special problem when undergoing open heart surgery since they refuse blood transfusion. We performed 15 open heart operations for both acquired and congenital heart disease using a modified version of isovolaemic haemodilution and bloodless prime technique of extracorporeal circulation. Two patients died. One death might have been at least indirectly related to the regimen which excludes blood substitution. We believe that our experience demonstrates the feasibility of open heart procedures in Jehovah's Witnesses, although the mortality risk is increased in these patients.

Troponin T as a marker of perioperative myocardial cell damage.

Unstable angina in patients undergoing CABG surgery is associated with a higher morbidity and mortality compared to patients with stable angina. Mortality ranges between 2 and 10% (20, 21). The importance of the preoperative status is only clear and well documented for patients with unstable angina who are unresponsive to medical treatment, patients who undergo emergency revascularization, and for patients with failed angioplasty. The adverse outcome in elective patients with unstable angina was statistically not significantly different from those with stable angina. Therefore, we may assume that in stabilized patients with unstable angina and minor myocardial cell damage intraoperative determinants like the duration of the aortic clamping period or the degree of revascularization are more relevant than the preoperative ones. These determinants may also be reflected by a marked and significant increase of troponin T in both groups during and after surgery. As for other cardiac enzymes, this increase of troponin T beginning immediately after reperfusion of the cardioplegic heart may limit its diagnostic value after cardiac surgery (6,22). On the other hand, troponin T may serve as a marker in assessing the effectiveness of different cardioprotective measures. Nevertheless, preoperatively elevated troponin T levels may indicate a jeopardized myocardium with an ongoing process of myocardial cell damage and may be of prognostic value. Antianginal and antiischemic therapy, therefore, has to be continued and completed until the day of surgery in these high-risk patients.

Activated thrombelastogram in neonates and infants with complex congenital heart disease in comparison with healthy children.

BACKGROUND: The goal of the study was to determine activated thrombelastographic (TEG(R)) parameters with the rotational TEG(R) (ROTEG or ROTEM) device (Pentapharm GmbH, Munich, Germany) in neonates and infants <1 yr with complex congenital heart disease (CCHD) and to compare them with those of healthy children. METHODS: A total of 59 children were included: Group I (Gr I) 24 children, ASA I, scheduled for minor surgery; and Group II (Gr II) 35 children with CCHD, ASA III-IV, scheduled for cardiac surgery. Each group was subdivided into four age groups. Blood samples were obtained before the surgical procedure. RESULTS: Statistically significant differences (two-way anova analysis) between Gr I and Gr II [mean (SD); P-value] were found in INTEG-CT [Gr I 175(19), Gr II 271(162); P=0.049], EXTEG-MCF [Gr I 63(8), Gr II 56(8); P=0.013], EXTEG-MCE [Gr I 186(65), Gr II 137(41); P=0.003], FIBTEG-MCF [Gr I 24(7), Gr II 19(5); P=0.012], FIBTEG-MCE [Gr I 32(13), Gr II 24(8); P=0.012] and EXTEG-MCE-FIBTEG-MCE [Gr I 155(55), Gr II 113(37); P=0.003]. Clotting time via contact activation was prolonged in Gr II and varied widely, mainly in the age group 0-1 month and to a lesser extent in 1-3 months, and maximum clot firmness was reduced in the same age groups. In comparison with Gr II, the healthy children showed relatively homogenous TEG values with a tendency to hypercoagulability; the maximum was found in age group 1-3 months, decreasing towards adult values in the course of the first year of life. CONCLUSIONS: These preliminary TEG results indicate that the coagulation-fibrinolytic system in CCHD patients <1 yr is functionally intact and balanced but at a lower level than in healthy children. This could be interpreted as a reduction in the haemostatic potential with less reserve.

Monitoring of selective antegrade cerebral perfusion using near infrared spectroscopy in neonatal aortic arch surgery.

BACKGROUND AND OBJECTIVE: To prevent neurological complications, low-flow antegrade cerebral perfusion (ACP) is used during repair of complex congenital heart defects. To overcome technical problems, continuous monitoring of cerebral blood flow and oxygenation is mandatory. The aim of the study was to evaluate the effect of different ACP flow rates on cerebral oxygen saturation obtained by near infrared spectroscopy. METHODS: Ten consecutive neonates undergoing Norwood stage I were included. In addition to near infrared spectroscopy (Invos 5100; Somanetics Corp., USA) on both hemispheres, mean arterial pressure and transcranial Doppler flow velocity were measured continuously and arterial and jugular venous oxygen saturation intermittently. Cerebral oxygen extraction ratio was calculated. Measurement points were obtained after starting bypass, during ACP with flow rates of 30, 20 and 10 mL kg(-1) min(-1) and immediately after ACP. ANOVA and Tukey-Kramer multiple comparison test were used for statistics. RESULTS: The near infrared spectroscopy signal could be obtained in all children at all measurement points, whereas transcranial Doppler failed in 1 neonate at a flow rate of 30 mL kg(-1)min(-1), in 3 neonates at 20 mL kg(-1) min(-1) and in 4 neonates at 10 mL kg(-1)min(-1). With the reduction of flow there was a significant decrease of cerebral oxygen saturation on both hemispheres (right: 78+/-8 to 72+/-9 and 66+/-8, P < 0.001; left: 71+/-7 to 65+/-7 and 60+/-7, P < 0.001), of jugular venous oxygen saturation (94+/-6 to 89+/-13 and 83+/-15, P < 0.001) and a significant increase in oxygen extraction ratio (9.1+/-8 to 14.8+/-14 and 21+/-16, P < 0.001) respectively, for 30, 20, 10 mL kg(-1)min(-1). CONCLUSION: Near infrared spectroscopy reliably detects flow alterations during ACP with profound hypothermia.

[Sinus node inhibitors in coronary surgery]. / Sinusknotenhemmer in der Koronarchirurgie.

In patients with coronary artery disease, rapid ventricular rates require adequate treatment since disturbed oxygen balance and ischemia may be incurred. By virtue of their isolated action on the sinus node, "specific bradycardic substances" have only negligible hemodynamic side effects and, accordingly, represent an alternative to other available rate-slowing drugs. The clonidine derivative, alinidine (N-allyl-clonidine) was used primarily as the specific bradycardic substance in our studies in patients at the time of aortocoronary bypass surgery. In addition to its rate-slowing properties, this substance also elicits an analgetic and anti-ischemic effect and, in a small percentage, it is metabolized to clonidine. The purpose of this study was to assess the effectiveness and hemodynamic actions of alinidine in the treatment of intraoperative heart rate acceleration and, in combination with the calcium channel blocker nifedipine, to evaluate its use for postoperative hypertension. The first study was performed in nine patients in whom, during aortocoronary bypass surgery, there was a heart rate increase in excess of 20% above the preoperative control value. Patients were excluded with impaired ventricular function, absence of sinus rhythm, concomitant increase in arterial mean pressure greater than 30%, hypovolemia, pulmonary capillary wedge pressure in excess of 15 mmHg as well as those with ECG changes precluding exact assessment of myocardial ischemia. In addition to the ECG, the following parameters were registered: heart rate, arterial pressure, central venous pressure and, with a semi-floating balloon-tipped catheter, pulmonary artery pressure as well as pulmonary wedge pressure. Cardiac output was determined with thermodilution.(ABSTRACT TRUNCATED AT 250 WORDS)