Acceleration and transport of relativistic electrons in the jets of the microquasar SS 433.

SS 433 is a microquasar, a stellar binary system that launches collimated relativistic jets. We observed SS 433 in gamma rays using the High Energy Stereoscopic System (H.E.S.S.) and found an energy-dependent shift in the apparent position of the gamma-ray emission from the parsec-scale jets. These observations trace the energetic electron population and indicate that inverse Compton scattering is the emission mechanism of the gamma rays. Our modeling of the energy-dependent gamma-ray morphology constrains the location of particle acceleration and requires an abrupt deceleration of the jet flow. We infer the presence of shocks on either side of the binary system, at distances of 25 to 30 parsecs, and that self-collimation of the precessing jets forms the shocks, which then efficiently accelerate electrons.

Pre-operative gastric ultrasound in patients at risk of pulmonary aspiration: a prospective observational cohort study.

Point-of-care gastric sonography offers an objective approach to assessing individual pulmonary aspiration risk before induction of general anaesthesia. We aimed to evaluate the potential impact of routine pre-operative gastric ultrasound on peri-operative management in a cohort of adult patients undergoing elective or emergency surgery at a single centre. According to pre-operative gastric ultrasound results, patients were classified as low risk (empty, gastric fluid volume ≤ 1.5 ml.kg-1 body weight) or high risk (solid, mixed or gastric fluid volume > 1.5 ml.kg-1 body weight) of aspiration. After sonography, examiners were asked to indicate changes in aspiration risk management (none; more conservative; more liberal) to their pre-defined anaesthetic plan and to adapt it if patient safety was at risk. We included 2003 patients, 1246 (62%) of which underwent elective and 757 (38%) emergency surgery. Among patients who underwent elective surgery, 1046/1246 (84%) had a low-risk and 178/1246 (14%) a high-risk stomach, with this being 587/757 (78%) vs. 158/757 (21%) among patients undergoing emergency surgery, respectively. Routine pre-operative gastric sonography enabled changes in anaesthetic management in 379/2003 (19%) of patients, with these being a more liberal approach in 303/2003 (15%). In patients undergoing elective surgery, pre-operative gastric sonography would have allowed a more liberal approach in 170/1246 (14%) and made a more conservative approach indicated in 52/1246 (4%), whereas in patients undergoing emergency surgery, 133/757 (18%) would have been managed more liberally and 24/757 (3%) more conservatively. We showed that pre-operative gastric ultrasound helps to identify high- and low-risk situations in patients at risk of aspiration and adds useful information to peri-operative management. Our data suggest that routine use of pre-operative gastric ultrasound may improve individualised care and potentially impact patient safety.

Dermatoglyphics as a possible morphological biomarker in myopia: analysis of finger ridge counts and fluctuating asymmetry.

BACKGROUND: The aim of this study is to provide the first analysis of finger ridge counts and fluctuating asymmetry in myopia, in order to evaluate dermatoglyphic role as a morphological biomarker. MATERIALS AND METHODS: Study sample consisted of 102 participants recruited from freshman students' population of the University of Pristina-Kosovska Mitro- vica. Prints were taken by standard ink and paper method. Differences in mean ridge counts between examined groups were analysed by ANOVA analysis of variance. Fluctuating asymmetry assessment was performed by using correlation method (p < 0.05). RESULTS: Analysis has identified myopic males as the group with the most pro- minent differences of examined dermatoglyphic parameters. Myopic males, compared to controls, have significantly higher ridge counts for left and right ring and little finger, as well as total ridge count. Also, this group has recorded significant difference in fluctuating asymmetry correlation score for middle finger, and borderline significance for thumb and ring finger. CONCLUSIONS: Overall findings of this study have indicated that dermatoglyphics might serve as a morphological biomarker, especially in myopic males, selecting them as the group with dermatoglyphic differences that might be suggestive of higher developmental instability. Although promising, the present results should be considered as preliminary until future investigations replicate them in a larger sample.

[Growth Guidance System in Treatment of Early Onset Scoliosis]. / Systémy usmernovaného rustu v lécbe raných detských skolióz.

PURPOSE OF THE STUDY The Growth Guidance System (GGS) represent a relatively new alternative to the traditional growing systems used for the treatment of early onset scoliosis. Ranking among the main aims of this surgical treatment is a three-dimensional correction of the deformity, maintenance of spinal growth and postponement of the necessity of final treatment by spondylodesis. MATERIAL AND METHODS Our study retrospectively evaluates the results of surgical correction in a group of 35 patients treated by GGS technique. The group consisted of patients with idiopathic, neuromuscular and syndromic spine deformity with the average age of 8 years and 2 months at the time of the surgery. The time of the follow-up is 3 years and 5 months on average. We evaluated the correction of the curve itself, the growth of the spine measured in the thoracic and lumbar part separately, and the growth of the trunk as a whole in the mentioned range on X-ray pictures. RESULTS The average correction of the scoliotic curve was 67%, from 75 preoperative degrees to 20 postoperative degrees. After the first operation 11% elongation of the trunk (from 321 mm to 356 mm) was reached, the thoracic spine was elongated by 10% (from 196 to 217 mm) and the lumbar spine was elongated by 11% (from 125 to 139 mm). The elongation of the trunk by 16% (from 322 to 375 mm) was observed in the cohort of patients with two years postoperative follow-up (21 patients). The total protraction of the trunk by 21% (from 318 to 386 mm) was reached in patients treated by definitive fusion (7 patients). DISCUSSION There is a very low number of studies analysing the long-term clinical results with the use of GGS. The first pilot results indicate that it is a technique allowing to achieve at least comparable results in correction of frontal plane compared with the distraction type of instrumentations. A negative aspect of this method is the abrasion of metal followed by metallosis. The new types of fixation screws enable more effective sliding of rods, maintenance of continuity of body grow by the shifting of rods as well as lower abrasion of the instrumentation. CONCLUSIONS The main advantage of GGS is the limited continuous growth of the spine, partial three-dimensional correction of the deformity, minimisation of inevitable reoperations under general anaesthesia and the possibility to quit a brace. Key words: growth guided system, early onset scoliosis, distraction, spinal growth, spondylodesis.

[S2 Alar-Iliac Screws in Fixation and Correction of Combined Neuromuscular Spinal and Pelvic Deformities]. / S2 alar-iliac srouby pri fixaci a korekci kombinovaných neuromuskulárních deformit pátere a pánve.

PURPOSE OF THE STUDY Neuromuscular deformities of the spine represent surgically uneasy to solve problems as well as serious handicaps causing sitting instability, pressure ulcers as well as pain. The aim of our study is to conduct a retrospective clinical analysis of the results of surgical correction of these deformities. This paper presents the use of a recent technique of sacral-alar-iliac (S2AI) screws and its comparison with other techniques of pelvic stabilisation. MATERIAL AND METHODS The group of 41 patients treated surgically with S2AI screws technique and transpedicular or hybrid instrumentation of the spine consisted of patients with the primary diagnosis of muscular dysthrophy, spinal muscular atrophy, cerebral palsy and some other neuromuscular diseases. The results of pelvic obliquity correction and scoliotic correction in combined neuromuscular deformities of the spine and pelvis were analysed. The technique of S2AI screws implantation and the possibility of their free-hand technique implementation were presented. RESULTS In the followed-up group of patients an average correction of pelvic obliquity by 81% (from 29.1 degrees before the operation to 5.6 degrees after the operation) was reported. On average, 74% correction of scoliotic spine deformity was achieved (from 83.3 degrees before the operation to 22.5 degrees after the operation). In both the cases neither a significant loss of correction at the minimum one-year follow-up nor any serious complications associated with grappling of pelvic fixation were observed. DISCUSSION The S2AI screws offer at least the same stability and ability of correction as iliac screws and at the same time they provide significantly better results compared with the older methods of pelvic fixation such as the Galvestone technique. With a good knowledge of the surgical technique and anatomical aspects this technique can be applied in the form of a free-hand technique. Navigation as well as robotic techniques can help with the accurate positioning of the S2AI screw. Transfixation of sacroiliacal syndesmosis in patients with a neuromuscular handicap does not lead to deterioration of their mobility. CONCLUSIONS Simultaneous stabilisation of spine and pelvis makes it possible to achieve a good quality correction of the deformity and good clinical results over a long period of time. It allows for stability of the sitting position of the patients and improves the quality of their lives. Nowadays, the S2AI screws are considered to be biomechanically the best quality pelvic fixation, eliminating subcutaneous prominence of the instrumentation and reducing the risk of skin decubitus. Key words:neuromuscular deformity, sacral-alar-iliac screw, pelvic obliquity, stabilization, scoliosis.

Multivariate analysis of preoperative and postoperative neutrophil-to-lymphocyte ratio as an indicator of head and neck squamous cell carcinoma outcome.

Recent publications have highlighted a greater utility of routine blood tests in patients with various cancers than previously assumed. It appears that the neutrophil-to-lymphocyte ratio (NLR) may be a good predictive biomarker for overall survival (OS) and disease-free survival (DFS). Preoperative and postoperative NLR data for patients with head and neck cancers have yet to be established. The aim of this study was to evaluate the preoperative and postoperative NLR in 182 patients with head and neck squamous cell carcinoma and to determine the association of NLR with OS and DFS. The statistical analysis of OS and DFS and their predictors was performed using Kaplan-Meier survival analysis and multivariate Cox proportional hazards regression analysis, with factors including age, sex, alcohol and tobacco use, tumour location, treatment after surgery, and lymphocyte and neutrophil counts. Longer OS was significantly associated with not consuming alcohol, preoperative neutrophil and lymphocyte counts, preoperative NLR, and the difference between the preoperative and postoperative NLR (P=0.016). Longer DFS was significantly associated with not consuming alcohol, preoperative neutrophil and lymphocyte counts, postoperative NLR, and the difference between preoperative and postoperative NLR (P=0.028).

[Scheuermann's Hyperkyphosis - Posterior-Only Surgical Approach Using the Smith-Petersen Osteotomies]. / Scheuermannova hyperkyfóza ­ operacní lécba solitárne zadním prístupem s vyuzitím Smith-Petersenových osteotomií.

PURPOSE OF THE STUDY Evaluation of efficiency and safety in surgically treated patients with Scheuermann hyperkyphosis using posterior-only surgical approach. MATERIAL AND METHODS Our study retrospectively evaluates the results of surgical correction in group of 20 patients with Scheuermann's hyperkyphosis, with an average age of 13 years and 8 month and with follow-up 4 years and 5 month. We evaluated changes of thoracic kyphosis as well as lumbar lordosis in correlation with surgical correction. Furthermore we compared ability of kyphosis to be corrected while performing reclination X-rays befroe surgery in comparation with rate of surgical correction. RESULTS The average correction of thoracic kyphosis was 52% - from preoperative 92° to postoperative 44°. We observed of 36% improvement of correction while surgically corrected in comparision with preoperative recklination X-ray pictures. Secondary correction of lumbar lordosis was from preoperative 84° to posoperative 55°. DISCUSSION Conservative treatment of hyperkyphosis offers only limited treatment results. Combined surgical approach with anterior release and posterior stabilization increase risk of anterior approach and secondary decreasing of lung capacity. Posterior vertberal osteotomies allows quality release and preparation for consecutive correction. Transpedicular instrumentation makes possible segmental correction of kyphotic spine using compression method. CONCLUSIONS Posterior-only surgical approach in combination with vertebral osteotomies allow efective and safe correction of hyperkyhosis in Scheuermann disease. Key words: Scheuermann, hyperkyphosis, transpedicular screws, osteotomy, posterior approach.

Towards satisfying performance of an O/W cosmetic emulsion: screening of reformulation factors on textural and rheological properties using general experimental design.

OBJECTIVE: Consumers' demand for improved products' performance, alongside with the obligation of meeting the safety and efficacy goals, presents a key reason for the reformulation, as well as a challenging task for formulators. Any change of the formulation, whether it is wanted - in order to innovate the product (new actives and raw materials) or necessary - due to, for example legislative changes (restriction of ingredients), ingredients market unavailability, new manufacturing equipment, may have a number of consequences, desired or otherwise. The aim of the study was to evaluate the influence of multiple factors - variations of the composition, manufacturing conditions and their interactions, on emulsion textural and rheological characteristics, applying the general experimental factorial design and, subsequently, to establish the approach that could replace, to some extent, certain expensive and time-consuming tests (e.g. certain sensory analysis), often required, partly or completely, after the reformulation. METHODS: An experimental design strategy was utilized to reveal the influence of reformulation factors (addition of new actives, preparation method change) on textural and rheological properties of cosmetic emulsions, especially those linked to certain sensorial attributes, and droplet size. RESULTS: The general experimental factorial design revealed a significant direct effect of each factor, as well as their interaction effects, on certain characteristics of the system and provided some valuable information necessary for fine-tuning reformulation conditions. Upon addition of STEM-liposomes, consistency, index of viscosity, firmness and cohesiveness were decreased, as along with certain rheology parameters (elastic and viscous modulus), whereas maximal and minimal apparent viscosities and droplet size were increased. The presence of an emollient (squalene) affected all the investigated parameters in a concentration-dependent manner. Modification of the preparation method (using Ultra Turrax instead of a propeller stirrer) produced emulsions with higher firmness and maximal apparent viscosity, but led to a decrease in minimal apparent viscosity, hysteresis loop area, all monitored parameters of oscillatory rheology and droplet size. CONCLUSION: The study showed that the established approach which combines a general experimental design and instrumental, rheological and textural measurements could be appropriate, more objective, repeatable and time and money-saving step towards developing cosmetic emulsions with satisfying, improved or unchanged, consumer-acceptable performance during the reformulation.

Oxo-Functionalized Graphene as a Cell Membrane Carrier of Nucleic Acid Probes Controlled by Aging.

We applied a fluorescein-containing oligonucleotide (ON) to probe surface properties of oxidized graphene (oxo-G) and observed that graphene-like patches are formed upon aging of oxo-G, indicated by enhanced probe binding and by FTIR spectroscopic analysis. By using a recently developed fluorogenic endoperoxide (EP) probe, we confirmed that during the aging process the amount of EPs on the oxo-G surface is reduced. Furthermore, aging was found to strongly affect cell membrane carrier properties of this material. In particular, freshly prepared oxo-G does not act as a carrier, whereas oxo-G aged for 28 days at 4 °C is an excellent carrier. Based on these data we prepared an optimized oxo-G, which has a low-defect density, binds ONs, is not toxic, and acts as cell membrane carrier. We successfully applied this material to design fluorogenic probes of representative intracellular nucleic acids 28S rRNA and ß-actin-mRNA. The results will help to standardize oxidized graphene derivatives for biomedical and bioanalytical applications.

New antiplatelet drugs and new oral anticoagulants.

In our daily anaesthetic practice, we are confronted with an increasing number of patients treated with either antiplatelet or anticoagulant agents. During the last decade, changes have occurred that make the handling of antithrombotic medication a challenging part of anaesthetic perioperative management. In this review, the authors discuss the most important antiplatelet and anticoagulant drugs, the perioperative management, the handling of bleeding complications, and the interpretation of some laboratory analyses related to these agents.

[Brown urine : Myoglobin-induced renal failure after concomitant administration of simvastatin and amiodarone]. / Brauner Urin : Myoglobininduziertes Nierenversagen nach gleichzeitiger Gabe von Simvastatin und Amiodaron.

Rhabdomyolysis is a rare but well-known complication of statin therapy. The risk is considerably increased when concomitant drugs are administered that inhibit metabolism and breakdown via the cytochrome CYP3A4. We report a case of myoglobin-induced acute renal failure secondary to the concomitant use of simvastatin and amiodarone. The risk of rhabdomyolysis is mainly determined by the statin dose; in the case of the concomitant use of CYP3A4 inhibitors, a maximal daily dose of 20 mg is recommended to avoid harmful drug interactions.

[PRESSURE ULCER ­ WHAT'S NEW]?

Pressure ulcer is defined as a wound resulting from tissue ischemia due to prolonged continuous pressure on the protruding parts of the body. Pressure ulcer is a significant health problem that more often affects the elderly and disabled. It can be noticed that a large number of patients who end up on prolonged and severe treatment are released from the hospital to home care without or with mild degree pressure ulcers. Therefore, the conclusion is that patient care in hospital conditions is satisfactory. It is important to emphasize the importance of maintaining the same level of care for patients at a high risk of pressure ulcers, considering all recommendations and innovations in preventing development of pressure ulcers.

Perioperative administration of fibrinogen does not increase adverse cardiac and thromboembolic events after cardiac surgery.

BACKGROUND: Although infusion of fibrinogen concentrate is increasingly used in bleeding patients after cardiac surgery, safety data are scarce. We aimed to evaluate the effect of perioperative administration of fibrinogen concentrate on postoperative morbidity and mortality in patients undergoing cardiac surgery. METHODS: During a 2 yr study period, 991 patients underwent cardiac surgery at a single university centre and were eligible for propensity score (PS) matching. We matched 190 patients with perioperative infusion of fibrinogen concentrate (median dose 2 g) with 190 controls without fibrinogen administration. After PS matching, crude outcome was analysed. Further, a multivariate logistic regression including additional risk factors for adverse outcome was performed. The primary endpoint was a composite of mortality and the occurrence of major cardiac and thromboembolic events within 1 yr. Secondary outcomes included mortality after 30 days and 1 yr and the composite of mortality and adverse events after 30 days. RESULTS: The administration of fibrinogen concentrate was not associated with an increased risk for mortality and thromboembolic or cardiac events within 1 yr after cardiac surgery [unadjusted hazard ratio (HR) 0.91; 95% confidence interval (CI) 0.55-1.49; P=0.697]. When using multivariate logistic regression model, the HR for adverse outcome in patients with administration of fibrinogen concentrate was 0.57 (95% CI 0.25-1.17; P=0.101). Similarly, the administration of fibrinogen concentrate did not adversely affect the secondary outcomes when applying unadjusted and multivariate regression analyses. CONCLUSIONS: Our study strongly suggests that the administration of fibrinogen concentrates at low dose is not associated with thromboembolic complications or adverse outcomes after cardiac surgery.

Age-related changes in the articular cartilage of the stifle joint in non-working and working German Shepherd dogs.

The aims of this study were to define age-related histological changes in the articular cartilage of the stifle joint in non-chondrodystrophic dogs and to determine whether physical activity has a positive impact on preservation of cartilage structure during ageing. Twenty-eight German shepherd dogs were included in the study. These dogs had no evidence of joint inflammation as defined by clinical assessment, radiology and synovial fluid analysis (specifically absence of synovial fluid serum amyloid A). The dogs were grouped as young working (n » 4), young non-working (n » 5), aged working (n » 13) and aged non-working (n » 6) animals. Gross changes in the stifle joints were recorded and biopsy samples of femoral and tibial articular cartilage were evaluated for thickness; chondrocyte number, density, surface area and morphology; isogenous group morphology; tidemark integrity; subchondral bone structure; presence of proteoglycans/ glycosaminoglycans; and expression of type I, II and X collagens. The major age-related changes, not related to type of physical activity, included elevated chondrocyte density and thinning of tibial cartilage and increased chondrocyte surface area in the superficial and intermediate zone of the femoral cartilage. There was also expression of type X collagen in the femoral and tibial calcified and non-calcified cartilage; however, type X collagen was not detected in the superficial zone of old working dogs. Therefore, ageing, with or without physical activity, leads to slight cartilage degeneration, while physical activity modulates the synthesis of type X collagen in the superficial cartilage zone, partially preserving the structure of hyaline cartilage.

Volatile anaesthetics and positive pressure ventilation reduce left atrial performance: a transthoracic echocardiographic study in young healthy adults.

BACKGROUND: Animal and in vitro studies suggest that volatile anaesthetics affect left atrial (LA) performance. We hypothesized that human LA pump function and dimensions are altered by volatile anaesthetics in vivo. METHODS: We performed transthoracic echocardiographic (TTE) measurements in 59 healthy subjects (aged 18-48 yr) undergoing minor surgery under general anaesthesia. The unpremedicated patients were randomly assigned to anaesthesia with sevoflurane, desflurane, or isoflurane. TTE examinations were performed at baseline and after induction of anaesthesia and upon placement of a laryngeal mask during spontaneous breathing. After changing to intermittent positive pressure ventilation (IPPV), an additional TTE was performed. The study focused on the velocity-time integral of late peak transmitral inflow velocity (AVTI) and maximum LA volume. RESULTS: We found no evidence for relevant differences in the effects of the three volatile anaesthetics. AVTI decreased significantly from 4.1 (1.2) cm at baseline to 3.2 (1.1) cm during spontaneous breathing of 1 minimum alveolar concentration of volatile anaesthetics. AVTI decreased further to 2.8 (1.0) cm after changing to IPPV. The maximum LA volume was 45.4 (18.6) cm(3) at baseline and remained unchanged during spontaneous breathing but decreased to 34.5 (16.7) cm(3) during IPPV. Other parameters of LA pump function and dimensions decreased similarly. CONCLUSIONS: Volatile anaesthetics reduced active LA pump function in humans in vivo. Addition of IPPV decreased LA dimensions and further reduced LA pump function. Effects in vivo were less pronounced than previously found in in vitro and animal studies. Further studies are warranted to evaluate the clinical implications of these findings. CLINICAL TRIAL REGISTRATION: NCT0024451.

Swings between rotation and accretion power in a binary millisecond pulsar.

It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutionary stages, these binaries host a radio millisecond pulsar whose emission is powered by the neutron star's rotating magnetic field. This evolutionary model is supported by the detection of millisecond X-ray pulsations from several accreting neutron stars and also by the evidence for a past accretion disc in a rotation-powered millisecond pulsar. It has been proposed that a rotation-powered pulsar may temporarily switch on during periods of low mass inflow in some such systems. Only indirect evidence for this transition has hitherto been observed. Here we report observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation-powered radio pulsar. Within a few days after a month-long X-ray outburst, radio pulses were again detected. This not only shows the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.

Impact of loss of high-molecular-weight von Willebrand factor multimers on blood loss after aortic valve replacement.

BACKGROUND: Severe aortic stenosis is associated with loss of the largest von Willebrand factor (vWF) multimers, which could affect primary haemostasis. We hypothesized that the altered multimer structure with the loss of the largest multimers increases postoperative bleeding in patients undergoing aortic valve replacement. METHODS: We prospectively included 60 subjects with severe aortic stenosis. Before and after aortic valve replacement, vWF antigen, activity, and multimer structure were determined and platelet function was measured by impedance aggregometry. Blood loss from mediastinal drainage and the use of blood and haemostatic products were evaluated perioperatively. RESULTS: Before operation, the altered multimer structure was present in 48 subjects (80%). Baseline characteristics and laboratory data were similar in all subjects. The median blood loss after 6 h was 250 (105-400) and 145 (85-240) ml in the groups with the altered and normal multimer structures, respectively (P=0.182). After 24 h, the cumulative loss was 495 (270-650) and 375 (310-600) ml in the groups with the altered and normal multimer structures, respectively (P=0.713). Multivariable analysis revealed no significant influence of multimer structure and platelet function on bleeding volumes after 6 and 24 h. After 24 h, there was no obvious difference in vWF antigen, activity, and multimer structure in subjects with and without the altered multimer structure before operation or in subjects with and without perioperative plasma transfusion. CONCLUSIONS: The altered vWF multimer structure before operation was not associated with increased bleeding after aortic valve replacement. Our findings might be explained by perioperative release of vWF and rapid recovery of the largest vWF multimers.

The influence of pre-admission hypoglycaemic therapy on cardiac morbidity and mortality in type 2 diabetic patients undergoing major non-cardiac surgery: a prospective observational study.

It remains unclear whether type 2 diabetics treated with either insulin or oral hypoglycaemic agents have the same incidence of cardiac morbidity and mortality after major non-cardiac surgery. We prospectively studied 360 type 2 diabetic patients undergoing major non-cardiac surgery of which 105 were treated with insulin only, 171 were treated with oral hypoglycaemics only and 84 were treated with a combination of insulin and oral hypoglycaemics. All-cause mortality after 30 days and after 12 months was highest in the insulin (10% and 26%) and lowest in the oral hypoglycaemics group (2% and 13%; p = 0.02 and 0.007, respectively). Insulin treatment was independently associated with increased mortality after 30 days (hazard ratio 3.93; 95% CI 1.22-12.64; p = 0.022) and 12 months (hazard ratio 2.03; 95% CI 1.16-3.58; p = 0.014) after multivariate adjustment for age, sex and the revised cardiac risk index (insulin treatment excluded). The increased mortality in insulin-treated diabetic patients may be due to a more progressive disease state in these patients rather than the treatment modality itself.

The influence of clinical risk factors on pre-operative B-type natriuretic peptide risk stratification of vascular surgical patients.

The role of the revised cardiac risk index in risk stratification has recently been challenged by studies reporting on the superior predictive ability of pre-operative B-type natriuretic peptides. We found that in 850 vascular surgical patients initially risk stratified using B-type natriuretic peptides, reclassification with the number of revised cardiac risk index risk factors worsened risk stratification (p < 0.05 for > 0, > 2, > 3 and > 4 risk factors, and p = 0.23 for > 1 risk factor). When evaluated with pre-operative B-type natriuretic peptides, none of the revised cardiac risk index risk factors were independent predictors of major adverse cardiac events in vascular patients. The only independent predictor was B-type natriuretic peptide stratification (OR 5.1, 95% CI 1.8-15 for the intermediate class, and OR 25, 95% CI 8.7-70 for the high-risk class). The clinical risk factors in the revised cardiac risk index cannot improve a risk stratification model based on B-type natriuretic peptides.

Remifentanil does not impair left ventricular systolic and diastolic function in young healthy patients.

BACKGROUND: Experimental studies and investigations in patients with cardiac diseases suggest that opioids at clinical concentrations have no important direct effect on myocardial relaxation and contractility. In vivo data on the effect of remifentanil on myocardial function in humans are scarce. This study aimed to investigate the effects of remifentanil on left ventricular (LV) function in young healthy humans by transthoracic echocardiography (TTE). We hypothesized that remifentanil does not impair systolic, diastolic LV function, or both. METHODS: Twelve individuals (aged 18-48 yr) without any history or signs of cardiovascular disease and undergoing minor surgical procedures under general anaesthesia were studied. Echocardiographic examinations were performed in the spontaneously breathing subjects before (baseline) and during administration of remifentanil at a target effect-site concentration of 2 ng ml(-1) by target-controlled infusion. Analysis of systolic function focused on fractional area change (FAC). Analysis of diastolic function focused on peak early diastolic velocity of the mitral annulus (e') and on transmitral peak flow velocity (E). RESULTS: Remifentanil infusion at a target concentration of 2 ng ml(-1) did not affect heart rate or arterial pressure. There was no evidence of systolic or diastolic dysfunction during remifentanil infusion, as the echocardiographic measure of systolic function (FAC) was similar to baseline, and measures of diastolic function remained unchanged (e') or improved slightly (E). CONCLUSION: Continuous infusion of remifentanil in a clinically relevant concentration did not affect systolic and diastolic LV function in young healthy subjects during spontaneous breathing as indicated by TTE.