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Biomedical subjects

L Frey

Publications and source records attributed to L Frey.

At least 19 recordsLinked to original sources
PubMed2006

[Health economic aspects of the use of blood and blood products].

An adequate supply of blood components for patients depends on the population's willingness to donate blood as well as on a well-organized blood donation system. In order to ensure the blood supply, a high expenditure is necessary. The article at hand describes two areas of the use of blood and blood products. First, it considers the application of factor concentrates in haemophiliacs (approximately 3000-4000 patients are regularly in need of treatment). For the German statutory health insurance, the estimated yearly expenses for factor concentrates is approx. 450 million Euros, the average costs per patient and year and per treatment center range between 40,903 and 117,597 Euros. The costs for an immune tolerance therapy (ITT) for patients with inhibitors are estimated to be between 70,300 and 3,800,000 Euros for children, depending on the length of the therapy and the degree of severity. In the second part of the article, the authors outline the status quo of the economic evaluation of cellular blood products and present the results of a German cross-sectional survey on the use of erythrocytes in orthopaedic surgery. Within the scope of this hemotherapy study, the transfusion rates vary considerably within the participating treatment centers [elective hip joint replacement (THR): 17 and 94%]. The average blood loss also differs significantly. Comparing the treatment centers, the calculated blood loss during THR shows considerable differences (median blood loss in treatment center with lowest/treatment center with highest blood loss: 883 ml/2,975 ml). The acceptance of low intraoperative hemoglobin values in the clinics is high and diverse. These differences in transfusion procedures between the treatment centers clearly show the need to take effective action in the area of quality assurance in order to make the most of the existent savings potential. Transparency of treatment processes is a necessary condition for an economic assessment and for optimal resource allocation.

Blood Banks↗
PubMed2006

The effect of inhaled nitric oxide and inhaled iloprost on hypoxaemia in a patient with pulmonary hypertension after pulmonary thrombarterectomy.

Acute pulmonary hypertension with life-threatening right heart failure may complicate the postoperative course following cardiothoracic surgery. Both inhaled nitric oxide and inhaled iloprost, a stable analogue of prostacyclin, have been used frequently for this purpose in acute pulmonary hypertension of various origins. We present a case of a patient with acute pulmonary hypertension and severely impaired gas exchange following pulmonary thrombo-endarterectomy. Therapy with one inhaled vasodilator alone did not satisfactorily abort a postoperative pulmonary hypertensive crisis and low-output syndrome due to right heart failure. Combined inhaled nitric oxide and inhaled iloprost, however, showed additive effects. Hence, the combination of both drugs may be reasonable in cases where the standard therapy fails. The effect has been demonstrated by means of continuous blood gas monitoring.

Administration, Inhalation↗
PubMed2005

Human herpesvirus 6 in bronchalveolar lavage fluid after lung transplantation: a risk factor for bronchiolitis obliterans syndrome?

Bronchiolitis obliterans syndrome (BOS) is the limiting factor to long-term survival after lung transplantation. Previous studies suggested respiratory viral tract infections are associated with the development of BOS. To identify the impact of virus detection in bronchoalveolar lavage (BAL) fluid, we analyzed BAL samples from 87 consecutive lung transplant recipients for human herpesvirus (HHV)-6, Epstein-Barr virus, Herpes simplex virus 1/2, Cytomegalovirus, respiratory syncytical virus and adenovirus by PCR. Acute rejection, BOS and death were recorded for a mean follow-up time of 3.27 +/- 0.47 years. Results of PCR analysis and other potential risk factors were entered into a Cox regression analysis of BOS predictors and death. Only acute rejection was a distinct risk factor for BOS of all stages, death and death from BOS. HHV-6 was detected in 20 patients. Univariate and multivariate analysis revealed that HHV-6 was associated with an increased risk to develop BOS > orb = stage 1 and death, separate from the risk attributable to acute rejection. Identification of HHV-6 DNA in BAL fluid is a potential risk factor for BOS. Our results warrant further studies to elucidate a possible causal link between HHV-6 and BOS.

Adenoviridae Infections↗
PubMed2001

Practical asymmetric synthesis of a selective endothelin A receptor (ETA) antagonist.

[structure: see text]. A practical, chromotography-free asymmetric synthesis was developed for the large scale preparation of an endothelin receptor antagonist 2. This synthesis includes a new efficient process for the preparation of 6-bromo-2,3-dihydrobenzofuran, a stereoselective conjugate addition of an aryllithium followed by stereospecific addition of the Grignard reagent of the top aryl bromide, and an aminophosphate-mediated sterospecific intramolecular enolate alkylation, which led to the formation of the five-membered ring bearing three contiguous asymmetric centers.

Antihypertensive Agents↗
PubMed2001

Prevention of secondary health conditions in adults with developmental disabilities: a review of the literature.

PURPOSE: To compile empirical findings regarding prevention strategies for secondary conditions experienced by adults with developmental disabilities. METHOD: The PsycLit and PubMed databases were searched for articles addressing the 20 most pervasive secondary conditions and the prevention of secondary conditions in general. RESULTS: Of more than 2000 articles examined, 25 met criteria for inclusion. None could be categorized as a primary approach to prevention, 19 involved secondary and six involved tertiary approaches. The majority included between one and ten participants. Nine studies involved the administration of treatment, three providing certain experiences, two chart review, and 11 a training approach. Injuries due to self-abuse, communication problems, dental hygiene problems, and problems with memory, persistence and mobility were addressed. CONCLUSION: Little is known regarding the prevention of secondary conditions within this population. The authors stress the necessity to focus research efforts on greater understanding of the linkage between disability, rehabilitation and public health models.

Adolescent↗
PubMed2001

Intensive care after minimally invasive and conventional coronary surgery: a prospective comparison.

OBJECTIVE: The purpose of this study was to compare the intensive care course of patients after minimally invasive coronary surgery to conventional coronary artery bypass grafting. DESIGN: Prospective observational study. SETTING: Intensive care unit of a university hospital. PATIENTS AND PARTICIPANTS: One hundred and five patients with two-vessel disease consecutively scheduled for elective coronary bypass surgery were enrolled. INTERVENTIONS: Two techniques of revascularization were performed: the Octopus procedure via median sternotomy without cardiopulmonary bypass (n = 52) and conventional coronary artery bypass grafting CABG (n = 53). MEASUREMENTS AND RESULTS: Three major categories describing the patients' postoperative course were defined: (1) clinical and laboratory findings, i.e., transfusion rate, catecholamine support, duration of ventilation, Simplified Acute Physiology Score II (SAPS II), serum levels of cardiac enzymes and lactic acid; (2) postoperative complications, i.e., incidence of myocardial infarction (MI), atrial fibrillation (AF), and neurological deficits; (3) this category was defined as "the extent of care" as represented by the Therapeutic Intervention Scoring System (TISS), and the length of stay in the ICU and in the hospital. In the Octopus group significantly lower figures were noted for duration of ventilation [6.1(5.5/9.5) vs 10.2(8.2/11.8) h], cardiac enzymes (CK-MB-Mass [5.1(2.0/8.3) vs 31.3(21.4/39.3) ng/ml], and lactic acid [2.0(1.5/3.3) vs 3.2(2.2/6.5) mmol/l]), incidence of AF (2/52 vs 9/53), and neurological deficits (0/52 vs 4/53), TISS score [72(44/83) vs 84(73/93)], LOS in the ICU [2(1/2) vs 2(2/2) days], and in the hospital [6(5/9) vs 9(8/12) days]. Catecholamine support, SAPS II scores, and incidence of MI of each group did not differ significantly. CONCLUSIONS: Off-pump coronary surgery via the Octopus technique was superior to conventional CABG regarding the course of patients in the early postoperative period. This implies benefits for the patients and the entire healthcare system.

APACHE↗
PubMed2001

High-resolution constant-height imaging with apertured silicon cantilever probes.

We present high-resolution aperture probes based on non-contact silicon atomic force microscopy (AFM) cantilevers for simultaneous AFM and near-infrared scanning near-field optical microscopy (SNOM). For use in near-field optical microscopy, conventional AFM cantilevers are modified by covering their tip side with an opaque aluminium layer. To fabricate an aperture, this metal layer is opened at the end of the polyhedral probe using focused ion beams (FIB). Here we show that apertures of less than 50 nm can be obtained using this technique, which actually yield a resolution of about 50 nm, corresponding to lambda/20 at the wavelength used. To exclude artefacts induced by distance control, we work in constant-height mode. Our attention is particularly focused on the distance dependence of resolution and to the influence of slight cantilever bending on the optical images when scanning at such low scan heights, where first small attractive forces exerted on the cantilever become detectable.

Journal Article↗
PubMed2001

[New platelet inhibitors].

The antiplatelet action of acetylsalicylic acid is mostly used in vascular medicine. In the meantime two other classes of platelet inhibiting agents have been introduced. Thieopyridines (Ticlyridin, Clopidogrel) have been shown to inhibit ADP induced platelet aggregation with persistence of this effect for several days after withdrawal. The short acting intravenous Glycoprotein IIb/IIIa inhibitors considerably improved the management of acute coronacy syndrome. The above mentioned compounds may be applied in combination at least for some days, and heparins are given in addition. Mainly the bleeding complications are to be taken into account especially if patients have to undergo emergency interventions. Hemodialysis or platelet concentrates are recommended to antagonise the antiplatelet effects immediately.

Anesthesia↗
PubMed2000

[Significance of perfusion of the gastrointestinal tract in shock].

The splanchnic perfusion is reduced early in the course of any shock. The mucosa of the gut suffers most as it experiences a high oxygen demand even in the steady state. The specific arrangement of the micro vessels within the villus of the mucosa exposes the tip of the villus at the highest risk for ischemia, particularly in low flow states. As a consequence the integrity of the mucosal layer is compromised and dysfunction of the mucosal barrier may allow bacteria and toxins to translocate from the gut lumen. Activation of leukocytes and stimulation of cytokine synthesis may comprise a sustained inflammatory response syndrome. So far there is a good body of evidence that the splanchnic region may play an important role in the pathophysiological sequence from shock to organ dysfunction.

Animals↗
PubMed2000

Markers of myocardial ischemia after minimally invasive and conventional coronary operation.

BACKGROUND: The purpose of this study was to evaluate the course of serum markers of myocardial tissue damage after two different types of minimally invasive coronary surgical procedures (MICS) as compared with conventional coronary artery bypass grafting (CABG). METHODS: We enrolled 87 patients with one- or two-vessel disease scheduled for one of the three procedures: minimally invasive direct coronary artery bypass grafting (MIDCABG) by lateral thoracotomy (n = 29), the OCTOPUS method by median sternotomy (n = 27), and CABG (n = 31). Creatine kinase activity (CK), creatine kinase MB activity (CK-MB act), creatine kinase MB mass concentration (CK-MB mass), myoglobin concentration (MG), and cardiac troponin I concentration (cTnI) were measured perioperatively until the second postoperative day. RESULTS: Creatine kinase-MB, CK-MB mass, and cTnI were significantly higher after CABG and were nearly maintained within the normal range in MICS. Creatine kinase and MG were significantly lower in the OCTOPUS group than in the MIDCABG or CABG groups. CONCLUSIONS: Minimally invasive coronary surgical procedures cause less myocardial injury than CABG as indicated by specific serum markers. However, higher CK and MG reflect more substantial skeletal muscle trauma during MIDCABG operation compared with OCTOPUS procedures.

Adult↗
PubMed2000

Intermittent atrial level right-to-left shunt with temporary hypoxemia in a patient during support with a left ventricular assist device.

We report a 56-year-old male patient developing hypoxemia after surgical replacement of infected valves of a left ventricular assist device (LVAD, Novacor) which had supported him during the previous 15 months. Contrast transesophageal echocardiography (TEE) revealed an atrial septal defect with intermittent right-to-left shunt across a patent foramen ovale. We postulate that the shunt detected in this patient occurred as a consequence of reduced pulmonary vascular compliance due to positive end-expiratory pressure (PEEP) and an increase of mean intrathoracic pressure. Furthermore, we hypothesize that synchronized LVAD operation exacerbates any potential right-to-left shunt due to the profound left ventricular unloading which occurs during LVAD support. In this first report of a right-to-left shunt from a previously unrecognized patent foramen ovale in a Novacor patient, the subsequent transient hypoxemia could be managed by avoiding PEEP of more than 3 mmHg, and mean airway pressure of more than 11 mmHg and by careful volume replacement in order to prevent the pump from completely emptying the left ventricle (LV) and the left atrium (LA). Thus, prior to every LVAD implantation a transesophageal contrast echocardiography with Valsalva maneuver should be performed to identify intracardiac right-to-left shunt.

Heart Septal Defects, Atrial↗
PubMed1999

Effects of noninvasive positive pressure ventilatory support in non-COPD patients with acute respiratory insufficiency after early extubation.

OBJECTIVE: To investigate the effects of noninvasive positive pressure ventilation (NPPV) on pulmonary gas exchange, breathing pattern, intrapulmonary shunt fraction, oxygen consumption, and resting energy expenditure in patients with persistent acute respiratory failure but without chronic obstructive pulmonary disease (COPD) after early extubation. DESIGN: Prospective study. SETTING: Multidisciplinary intensive care unit of a university hospital. PATIENTS: 15 patients after prolonged mechanical ventilation (> 72 h) with acute respiratory insufficiency after early extubation. INTERVENTIONS: Criteria for early extubation were arterial oxygen tension (PaO2) > or = 40 mm Hg (fractional inspired oxygen 0.21), arterial carbon dioxide tension (PaCO2) < or = 55 mm Hg, pH > 7.32, respiratory rate < or = 40 breaths per min, tidal volume (VT) > or = 3 ml/kg, rapid shallow breathing index < or = 190 and negative inspiratory force > or = 20 cmH2O. After extubation, two modes of NPPV were applied [continuous positive airway pressure (CPAP) of 5 cmH2O and pressure support ventilation (PSV) with 15 cmH2O pressure support]. MEASUREMENTS AND MAIN RESULTS: Oxygenation and ventilatory parameters improved during both modes of NPPV (p < 0.05): increase in PaO2 of 11 mm Hg during CPAP and 21 mm Hg during PSV; decrease in intrapulmonary shunt fraction of 7% during CPAP and 12% during PSV; increase in tidal volume of 1 ml/kg during CPAP and 4 ml/kg during PSV; decrease in respiratory rate 6 breaths/min during CPAP and 9 breaths/min during PSV. Oxygen consumption (15% during CPAP, 22% during PSV) and resting energy expenditure (12% during CPAP, 20% during PSV) were reduced (p < 0.05). PaCO2 decreased, whereas minute ventilation and pH increased during PSV (p < 0.05). The median duration of NPPV was 2 days. Two patients had to be reintubated. CONCLUSIONS: In non-COPD patients with persistent acute respiratory failure after early extubation, NPPV improved pulmonary gas exchange and breathing pattern, decreased intrapulmonary shunt fraction, and reduced the work of breathing.

APACHE↗
PubMed1998

Procalcitonin as a marker of systemic inflammation after conventional or minimally invasive coronary artery bypass grafting.

Cardiac surgery using cardiopulmonary bypass (CPB) often induces a systemic inflammatory response syndrome (SIRS). The concept of minimally invasive direct coronary artery bypass (MIDCAB) eliminates cardiopulmonary bypass. We evaluated the perioperative time course of procalcitonin (PCT) to compare the inflammatory response due to these two different surgical procedures. 57 patients were studied: CABG with CPB (n = 30), MIDCAB without CPB (n = 27). The following data were measured preoperatively, after induction of anesthesia, after separation from CPB in the CABG group or after left internal mammary artery (LIMA)-to-left anterior descending artery (LAD) anastomosis in MIDCAB group, and every 3 hours for the first 42 hours in the ICU: PCT, C-reactive protein (CRP), body temperature, hemodynamic parameters, and the need for catecholamines. Leucocyte counts were measured daily. For statistical analyses the Friedmann, Wilcoxon, or Mann-Whitney U tests were used. PCT in the CABG group rose to a maximum of 2.0 ng/ml (median) at 15 hrs postoperatively. In the MIDCAB group maximal PCT concentration was 0.7ng/ml (median) (p < 0.05). CRP was elevated to 17.1 mg/dl in the CABG and 18.5mg/dl in the MIDCAB group (n.s.). The leucocyte counts were increased on day 2 in the CABG group (p < 0.05). In the CABG group about 25% of the patients needed noradrenaline, but in the MIDCAB group none (p < 0.05). Body temperature did not differ between both groups. The increase in PCT concentration was more pronounced after CABG, indicating a reduced inflammatory response after MIDCAB. CRP was increased after both procedures. PCT reflects the inflammatory response after cardiac bypass surgery with or without CPB.

Aged↗
PubMed1997

[Small-volume resuscitation for hypovolemic shock. Concept, experimental and clinical results].

The concept of small-volume resuscitation, the rapid infusion of a small volume (4 ml/kg BW) of hyperosmolar 7.2-7.5% saline solution for the initial therapy of severe hypovolemia and shock was advocated more than a decade ago. Numerous publications have established that hyperosmolar saline solution can restore arterial blood pressure, cardiac index and oxygen delivery as well as organ perfusion to pre-shock values. Most prehospital studies failed to yield conclusive results with respect to a reduction in overall mortality. A meta-analysis of preclinical studies from North and South America, however, has indicated an increase in survival rate by 5.1% following small-volume resuscitation when compared to standard of care. Moreover, small-volume resuscitation appears to be of specific impact in patients suffering from head injuries with increased ICP and in severest trauma requiring immediate surgical intervention. Results from clinical trials in Austria, Germany and France have demonstrated positive effects of hyperosmolar saline solutions when used for fluid loading or fluid substitution in cardiac bypass and in aortic aneurysm surgery, respectively. A less positive perioperative fluid balance, a better hemodynamic stability and improved pulmonary function were reported. In septic patients oxygen consumption could significantly be augmented. The most important mechanism of action of small-volume resuscitation is the mobilisation of endogenous fluid primarily from oedematous endothelial cells, by which the rectification of shock-narrowed capillaries and the restoration of nutritional blood, flow is efficiently promoted. Moreover, after ischemia reperfusion a reduction in sticking and rolling leukocytes have been found following hyperosmolar saline infusion. Both may be of paramount importance in the long-term preservation of organ function following hypovolemic shock. An increased myocardial contractility in addition to the fluid loading effects of hyperosmolar saline solutions has been suggested as a mechanism of action. This, however, could not be confirmed by pre-load independent measures of myocardial contractility. Some concerns have been raised regarding the use of hyperosmolar saline solutions in patients with a reduced cardiac reserve. A slower speed of infusion and adequate monitoring is recommended for high risk patients. Recently, hyperosmolar saline solutions in combination with artificial oxygen carriers have been proposed to increase tissue oxygen delivery through enhanced O2 content. This interesting perspective, however, requires further studies to confirm the potential indications for such solutions. Many hyperosmolar saline colloid solutions have been investigated in the past years, from which 7.2-7.5% sodium chloride in combination with either 6-10% dextran 60/70 or 6-10% hydroxyethyl starch 200,000 appear to yield the best benefit-risk ratio. This has led to the registration of the solutions in South America, Austria, The Czech Republic, and is soon awaited for North America.

Dextrans↗