Functional evaluation of platelet aspirin resistance after on-pump coronary bypass grafting using multiple aggregation tests.

OBJECT: The predominant mechanism of early graft failure after coronary artery bypass grafting (CABG) is associated with antiplatelet treatment using drugs such as acetylsalicylic acid (ASA). Impaired hemostasis of multiple etiologies is often present in patients undergoing on-pump cardiac surgery. We investigated the impact of intravenous ASA administration on platelet function in this setting. METHODS: Forty-two patients were enrolled in the study. Patients received 100 mg oral ASA once daily, beginning in the early postoperative period. Noncompliance was eliminated by the administration of 300 mg ASA intravenously at 6-8 days post-operation. Blood was drawn immediately before, 1 h and 24 h after ASA administration. RESULTS: A platelet function analyzer (PFA-100™) was used to evaluate closure time (CT), turbidimetric platelet aggregation (TPA) and impedance platelet aggregation (IPA) induced by arachidonic acid (AA), collagen and ADP and results were compared with the respective values from 120 healthy individuals. At 1 h and 24 h after administration, we found that intravenous ASA caused CEPI-CT to be significantly prolonged with a reduction of AA and collagen-induced IPA. Despite postoperative oral ASA administration for 6-8 days, PFA-100™ CEPI and CADP-CT were significantly shorter and ADP-TPA and IPA values induced by any agonist were significantly greater in patients than in controls. Intravenous ASA had no significant influence on CADP-CT or ADP-induced IPA (ADP-IPA). CONCLUSION: Platelet tests for diagnosing patients as aspirin responders (ASA-R) or aspirin non-responders (ASA-NR) were found to be not comparable. Patients after CABG show augmented platelet dysfunction. Intravenous ASA administration may indicate a promising approach to reduce laboratory resistance after CABG procedure. The reason for this is not clear and requires additional clinical studies.

Middle-Level Features for the Explanation of Classification Systems by Sparse Dictionary Methods.

Machine learning (ML) systems are affected by a pervasive lack of transparency. The eXplainable Artificial Intelligence (XAI) research area addresses this problem and the related issue of explaining the behavior of ML systems in terms that are understandable to human beings. In many explanation of XAI approaches, the output of ML systems are explained in terms of low-level features of their inputs. However, these approaches leave a substantive explanatory burden with human users, insofar as the latter are required to map low-level properties into more salient and readily understandable parts of the input. To alleviate this cognitive burden, an alternative model-agnostic framework is proposed here. This framework is instantiated to address explanation problems in the context of ML image classification systems, without relying on pixel relevance maps and other low-level features of the input. More specifically, one obtains sets of middle-level properties of classification inputs that are perceptually salient by applying sparse dictionary learning techniques. These middle-level properties are used as building blocks for explanations of image classifications. The achieved explanations are parsimonious, for their reliance on a limited set of middle-level image properties. And they can be contrastive, because the set of middle-level image properties can be used to explain why the system advanced the proposed classification over other antagonist classifications. In view of its model-agnostic character, the proposed framework is adaptable to a variety of other ML systems and explanation problems.

Levosimendan in patients with acute myocardial ischaemia undergoing emergency surgical revascularization.

BACKGROUND AND OBJECTIVE: Levosimendan is a calcium-sensitizing drug that enhances myocardial contractility without increasing intracellular calcium. By activating adenosine triphosphate-dependent potassium channels it exerts cardioprotective and vasodilatory effects. METHODS: A retrospective matched pair analysis was performed in 52 patients undergoing emergency coronary artery bypass grafting for acute myocardial ischaemia with or without cardiogenic shock. A total of 27 patients received levosimendan (bolus 6 microg kg(-1); continuous infusion 0.2 microg kg(-1) min(-1)) in addition to catecholamines, while 25 patients were treated with catecholamines only. RESULTS: Predicted mortality by logistic EuroSCORE was 42% (14-90%) in the levosimendan group and 38% (9-90%) in the control group (median, range). Cardiogenic shock was diagnosed in 52% of the patients in both groups. Compared to the control group, levosimendan-treated patients had fewer intra-aortic balloon pumps inserted (33% vs. 76%, P 0.05) and need for dialysis (11% levosimendan; 32% control, P > 0.05) did not reach statistical significance. Length of hospital stay did not differ (14 +/- 18 days, levosimendan; 13 +/- 19 days, control; P > 0.05) between the two groups. CONCLUSION: In this retrospective matched pair analysis of 52 patients undergoing emergency coronary artery bypass grafting for acute ischaemia, levosimendan reduced morbidity. The reduced morbidity did not translate into reductions in mortality or length of stay. A larger, prospective randomized trial is warranted to confirm the potentially beneficial effects of levosimendan in patients with acute ischaemia.

Prophylactic use of pentoxifylline on inflammation in elderly cardiac surgery patients.

BACKGROUND: Inflammation plays a pivotal role in the pathogenesis of organ injury after cardiopulmonary bypass (CPB). Elderly patients appear to be especially prone to develop general inflammation. Use of pentoxifylline (PTX) before surgery may be a promising approach to minimize the negative effects of CPB in these patients. METHODS: In a prospective, randomized study, patients more than 80 years old undergoing aortocoronary artery bypass grafting received either PTX (n = 15) after induction of anesthesia (initial bolus of 300 mg followed by a continuous infusion of 1.5 mg.kg(-1).h(-1) during the next 2 days) or saline as placebo (control group; n = 15). Polymorphonuclear neutrophil (PMN) elastase, C-reactive protein (CRP), and interleukins (IL-6, IL-8, IL-10) were measured from arterial blood samples before surgery (T0), at the end of surgery (T1), 5 hours after surgery (T2), and at the morning of the first (T3) and second (T4) postoperative day. RESULTS: Postoperatively, PTX-treated patients less often needed catecholamines and were extubated earlier than the control patients (p < 0.05). On the intensive care unit, cardiac index inceased more in the PTX-treated (from 1.95 +/- 0.3 to 3.26 +/- 0.4 L.min(-1).m(-2)) than in the control patients (from 1.89 +/- 0.2 to 2.78 +/- 0.3 L.min(-1).m(-2)). Increase in CRP and PMN-elastase was significantly higher in the untreated control than in the PTX patients. After CPB, IL-6, IL-8, and IL-10 increased in both groups showing a significantly higher increase in the untreated control patients (IL-8 control: from 11.3 +/- 2.6 to 154.4 +/- 57 pg/mL [T1]); IL-8 PTX: from 10.9 +/- 2.7 to 71.8 +/- 23 pg/mL [T1]). CONCLUSIONS: In elderly cardiac surgery patients, use of PTX before surgery and continued after CPB resulted in less inflammatory response than in an untreated control group. The value of attenuating the inflammatory process by PTX on outcome in this patient population needs to be evaluated in further controlled studies.

A predictive parameter in patients with brain related complications after cardiac surgery?

OBJECTIVE: The prognostic estimation of cerebral complications after cardiac surgery is a major problem in the early postoperative period. Neuron specific enolase (NSE) is an enzyme involved in glycolysis, which is localized in neurons and axonal processes. It escapes into the blood and cerebrospinal fluid at the time of neural injury. Therefore we focused the study on the question of how far serum levels of neuron specific enolase can predict the neurological and neuropsychological outcome after cardiac surgery. METHODS: We determined, with a prospective study design of NSE serum levels in 200 patients undergoing cardiac surgery preoperatively, right after the operation and 48 h later. The NSE was measured with a solid phase enzyme immuno assay which utilized a highly specific monoclonal antibody to NSE. We evaluated the neurological and neuropsychological status before and 72 h after surgical intervention. As a control group we recruited 50 patients undergoing general surgical treatment. RESULTS: The preoperative serum levels of NSE are constantly low in all patients with a mean value of 11.1 ng/ml (8.3-13.6) and a mean +/- S.D. of 3.12 in the main group and a mean value of 9.6 ng/ml (7.8-10.3) and a mean +/- S.D. of 1.84 in the control group. The early postoperative measurements indicated a significant increase to a mean value of 19.7 ng/ml (8.7-70.9) with a mean +/- S.D. of 2.89 in the main group. In contrast there is no increase of NSE serum levels after general surgery. The 48 h postoperative mean levels declined to 14.2 ng/ml (9.9-26.2), S.D. of 3.23. In 17 out of the 200 patients a neurological complication occurred. Elevated NSE levels were found in 16 of these 17 patients. The highest concentrations of NSE were measured in 7 patients with the most severe neurological complications being transient ischemic attack and stroke. CONCLUSIONS: The early serum levels of NSE after cardiopulmonary bypass, in those patients with severe neurological deficits, indicate that NSE is a suitable marker for the detection and quantification of cerebral injury after open heart surgery. Therefore, in addition NSE seems to be of predictive value for the clinical outcome and gives implications for the treatment and prognosis of patients with brain related complications in cardiac surgery.

Minimally invasive saphenous vein harvesting: is there an improvement of the results with the endoscopic approach?

OBJECTIVES: In the postoperative course after conventional open removal of the greater saphenous vein, wound healing disturbances are common and often painful. Therefore the primary goal of this investigation was to prove the safety and practicability of this new less invasive technique for saphenous vein harvesting and the effect on complications and morbidity. METHODS: The study comprised 103 coronary artery bypass grafting (CABG) patients with an endoscopic approach to harvest the saphenous vein (MIVH). We used the VasoView II system developed by Origin, and compared the intraoperative procedure time and the clinical results with 105 equivalent patients in which a conventional open technique was used. RESULTS: In 101 patients endoscopic vein harvesting was successful; a conversion into open technique was necessary in two patients. On average 2.6 vein segments could be harvested in the endogroup versus 2.9 segments in the opengroup. The mean procedure time was 13.2 min per segment in the endogroup compared to 12.2 min per segment in the opengroup. Relevant hematoma were found in 29 patients (27.6%) of the opengroup, whereas only nine patients (8.7%) of the endogroup revealed severe hematoma. Infection was apparent in nine patients (8.5%) after conventional vein harvesting. Two infections were found after endoscopic intervention. CONCLUSIONS: Endoscopic saphenous vein harvesting as part of a less invasive concept in cardiac surgery is a safe and after the learning curve, fast alternative to harvest the saphenous graft. The cosmetic result is excellent and the complication rate seems to be lower. It must be noted however, that the cost effectiveness of the method has to be proved and that further histological and functional studies are needed in order to check the intimal structure of the vein.

[Tricuspid valve endocarditis. Demonstration of a rare disease exemplified with 3 case reports]. / Trikuspidalklappenendokarditis. Darstellung eines seltenen Krankheitsbildes anhand dreier Fallberichte.

BACKGROUND: Endocarditis of the tricuspid valve is a rare form of valvular endocarditis and occurs mainly in patients with special risk factors. CASE REPORTS: The three case reports demonstrate 3 young patients (age 30 to 37 years, 2 female and 1 male) with a typical history of those risk factors. The two women were intravenous drug addicts and one of them had suffered already an episode of tricuspid valve endocarditis several years ago. The man developed his infection after implantation of a pacemaker. In all of the three patients the endocarditis was due to infection with staphylococci twice staphylococcus epidermidis and once staphylococcus aureus. In two of the three patients the endocarditis could not be cured by intravenous antibiotics alone and these patients had to undergo cardiac valvular surgery. All patients left the hospital after several weeks without signs of infection. CONCLUSION: In clinical praxis the introduction of a special endocarditis service, a small team which has to be consulted in every suspected case of endocarditis, seems to be beneficial as well as the use of the Duke criteria for diagnosis in those cases.

Bispectral index and electroencephalographic entropy in patients undergoing aortocoronary bypass grafting.

BACKGROUND AND OBJECTIVE: This study was conducted to compare bispectral index, state entropy and response entropy in patients undergoing coronary artery bypass grafting. METHODS: In 66 patients, anaesthesia was maintained at two different levels using bispectral index. Doses of sufentanil and midazolam were adjusted to achieve a bispectral index in the range of 45-55 in 33 patients (BIS 50 group) and 35-44 in another 33 patients (BIS 40 group). Simultaneously, state entropy and response entropy were recorded. RESULTS: The targeted values of bispectral index were achieved in both groups and the bispectral index values differed significantly during whole anaesthesia. Median response entropy and state entropy fell to 19-26 during anaesthesia in both groups. Response entropy and state entropy values in the two groups differed significantly only after induction of anaesthesia and did not differ during further anaesthesia. There was no explicit intraoperative recall in both groups. Patients in Group BIS 40 received significantly (P<0.05) more sufentanil than the BIS 50 group (704+/-181 microg vs. 490+/-107 microg, respectively) and midazolam (18.5+/-6.1 mg vs. 15.6+/-3.8 mg, respectively). After cardiopulmonary bypass, significantly (P<0.05) more patients in Group BIS40 needed inotropic support with dobutamine (79%) than in the BIS50 group (52%). Time to extubation did not differ between the two groups. CONCLUSION: In patients undergoing coronary artery bypass grafting, no relationship was found between bispectral index levels and state entropy and response entropy at two different stages of a sufentanil-midazolam anaesthesia. A bispectral index level of 45-55 reduced anaesthetic medications used and the need for inotropic support.

Surface modification of extracorporeal circuits: is there really an impact on cerebral performance after cardiopulmonary bypass?

BACKGROUND: Pathophysiology of extracorporeal circulation is multifactorial, and the link between newly developed "biomaterials" and clinical outcome is not easy to illustrate. MATERIAL AND METHODS: We designed a randomized, double-blinded, prospective study in order to verify the impact of a new surface modification [SMAR(X)T] in combination with an optimized blood air interface, on the cerebral performance after cardiopulmonary bypass. 80 patients were randomly divided into two subgroups (SMAR(X)T vs. standard PVC control) and analyzed for the kinetic of cerebral ischemia markers neuronspecific enolase, protein S100 and neuropsychologically tested with the Mini-Mental-Status Test (MMST) before and after the operation. RESULTS: We could not show significant differences of protein S100 and neuron-specific enolase (NSE) levels between SMAR(X)T patients and the controls, but the incidence of neurological complications was exceptionally low. Although no statistically significant differences could be obtained for the MMST, the different pointloss between both groups trends toward a better cerebral performance in SMAR(X)T patients. CONCLUSION: The use of a biologically inert circuit in combination with an optimized perfusion management seems to be worthy of recommendation.

Cell saver, ultrafiltration and direct transfusion: comparative study of three blood processing techniques.

BACKGROUND: Intraoperative blood salvage is an important part of blood conservation efforts in cardiac surgery. The purpose of this study is to examine the effects of three different circuit blood-salvaging techniques: centrifugation, ultrafiltration and direct infusion. METHODS: Sixty patients undergoing elective coronary bypass graft procedures were randomly assigned in a prospective manner to one of the three blood-salvaging methods. RESULTS: Intra- and postoperative blood samples demonstrated increased hemoglobin values in the direct infusion group and higher platelet count in the ultrafiltration group. There were no significant differences in these results. The analysis of coagulation parameters revealed a similar prolongation of partial thromboplastin time and activated clotting time in all groups. The amount of blood loss was not significantly different between the three blood conservation methods. The effect of direct infusion method does not result in either major disturbance of coagulation parameters or in increased blood loss. CONCLUSION: In a sample of adult patients undergoing coronary artery bypass grafting, direct transfusion is, in consideration of the cost-effective factor, an appropriate approach for returning cardiopulmonary bypass circuit blood.

VAMOS--ventilator assisted model for off-pump surgery.

BACKGROUND: Introduction of innovative cardiac procedures mostly depends on extensive evaluation using laboratory animal models. Avoiding living creatures in the experimental setup where possible without loss of reliability would be progressive from a logistical as wells as an ethical perspective. METHODS: Hearts of meat-production animals (pigs) were removed without structural damage. Two tracheotomy tubes (length 35 mm, diameter 10 mm) were inserted into aortic and pulmonal positions. The atrial inflow had to be ligated. The ventilation tubes were joined to a respirator. The "ventilation" frequency was limited to a maximum of 100/min, "inspiration" volume at 100 ml and ventilation pressure at up to 60 mbar. RESULTS: "Air beats" triggered by the frequency of the respirator occurred in the ventilated heart. Insufflation and deflation generated movement that was almost the same as physiological action. CONCLUSIONS: Air-animation of the heart using a standard respirator is an easily conducted alternative to extensive and expensive laboratory experiments for development and quality control of new devices or techniques without compromising the scientific value of results and without using living animals.

Survival and quality of life after a long-term intensive care stay.

OBJECTIVE: The growing number of high-risk patients in cardiac surgery unavoidably leads to more complications, and therefore to a prolonged stay in an intensive care unit (ICU). The aim of our investigation was to elaborate on the fate of patents after long-term ICU treatment. METHODS: Out of 5055 patients, 232 had to be treated for longer than 5 days in ICU. These 232 patients were analyzed for in-hospital mortality and followed up for quality of life. The Barthel mobility index and geriatric depression scale by Sheikh and Yesavage were used to evaluate physical ability and mood disturbances. Follow-up time was 82 months, and could be completed for 99 % of the patents. RESULTS: In-hospital mortality was 34.6 %, with the majority of cases being coronary artery bypass grafting procedures (59.9 %). Average stay in ICU was 12.0 days for the survivors and 17 days for non-survivors. During follow-up time (6 - 82 months), another 56 patients (23 %) died. Survivors (n = 98) were predominantly in NYHA classes l-ll (83 %) with a Barthel index of more than 80, representing adequate mobilization during daily life in 78 % of the patients. Results according to the geriatric depression scale were normal in the vast majority of patients (91 %) with severe or life threatening depressions in only 6 patients (8 %). CONCLUSION: Long-term treatment of critically ill patients is admittedly burdened with high in-hospital and follow-up mortality. However, the excellent physical and psychological recovery of survivors unequivocally supports the employment of all technical and personnel resources within modern intensive care medicine.

Impact of atrio-biventricular pacing to poor left-ventricular function after CABG.

AIMS: The relation between acute postoperative management of epicardial pacing and haemodynamic status in patients with poor left-ventricular function after coronary artery bypass grafting (CABG) demonstrates the importance of synchronous ventricular activation and contraction during the vulnerable early postoperative period. METHODS: in 22 patients (mean age - 69.3 +/- 5.4 years) with poor left-ventricular function (ejection fraction 29.8 +/- 4.8), we compared the postoperative haemodynamic parameters between atrio-biventricular, atrio-monoventricular and atrial pacing 3 - 24 hours after elective coronary artery revascularisation. Temporary epicardial pacing electrodes were placed on the right atrium and the paraseptal region of the left and right ventricle. The ventricular pacing modus was confirmed by surface electrocardiogram (EGG). We used overdrive rate pacing. RESULTS: In patients with left bundle branch block, atrio-left-ventricular and atrio-biventricular pacing increased cardiac index and decreased wedge pressure. Atrial pacing and atrio-right-ventricular pacing decreased cardiac index. In contrast, atrio-right-ventricular and atrio-biventricular pacing increased cardiac index in patients with right bundle brunch block. CONCLUSION: Atrio-biventricular pacing increased cardiac index and decreased wedge pressure compared with AAI pacing. In patients with wall-motion abnormalities and impaired cardiac conduction, a site-specific pacing therapy can help to optimize postoperative haemodynamics and reduce the application of inotropic substances.

[Direct dilatation and emergency bypass operation of main branch occlusion in acute anterior wall infarct and cardiogenic shock]. / Direkt-Dilatation und notfallmässige Bypass-Operation eines Hauptstammverschlusses bei akutem Vorder-wandinfarkt und kardiogenem Schock.

Occlusion of the left main coronary artery (LMCA) is the cause of myocardial infarction in about 0.04%. Those patients who do not die during the acute phase often do have a dominant right coronary artery with extensive collaterals to the left coronary artery. Because this is a very rare situation there are only some cases reports dealing with the management of these patients. A 60 years old woman was admitted to our hospital with the signs of an acute Q-wave anterior myocardial infarction. Within a few minutes after the arrival she developed a cardiogenic shock. Coronary angiography was performed immediately. The left main coronary artery was occluded and a big right coronary artery showed a significant stenosis. There were many collaterals from the right coronary artery supplying the left coronary artery. After information of the cardiac surgeons, primary angioplasty of the LMCA was performed in order to achieve hemodynamic stabilisation and to relieve symptoms. Reperfusion of the left anterior descendent coronary artery (LAD) could be achieved within 30 minutes. This led to hemodynamic stabilisation of the patient. But a significant residual stenosis of the LMCA remained and the circumflex artery was still occluded. In the meanwhile cardiac surgery was able to be performed and so the patient was transferred to surgery without further dilatation or stent implantation. Four venous grafts (LAD, first diagonal branch, circumflex artery and right coronary artery) were inserted. After 4 weeks the patient was in a good shape and could be discharged at home. Primary angioplasty seems to be an effective treatment in patients with acute myocardial infarction and an occlusion of the LMCA. But coronary bypass surgery is nearly almost necessary during the following period in order to achieve complete revascularisation and to improve survival.

[Is levosimendan an inoprotective drug in patients with acute coronary syndrome undergoing surgical revascularization?]. / Wirkt Levosimendan bei der operativen Versorgung des akuten Koronarsyndroms inoprotektiv?

Levosimendan, is a new calcium sensitiser with 2 major effects. First, levosimendan acts as a positive inotropic agent by binding calcium dependently to cardiac troponin C. Second, levosimendan activates adenosine triphosphate-regulated potassium (K (ATP)) channels. Thus it has vasodilatory properties and cardioprotective effects at a dose enhancing myocardial contractility. These unique properties of levosimendan might be of great advantage in patients with myocardial ischemia simultaneously requiring inotropic support. The concept of perioperative inoprotection is presented in 6 patients with acute ischemia undergoing emergent cardiac surgery.

Pain management in cardiac surgery patients: comparison between standard therapy and patient-controlled analgesia regimen.

OBJECTIVE: To compare standard nurse-based pain therapy with a patient-controlled analgesia (PCA) regimen. DESIGN: Prospective, randomized study. SETTING: Single-institutional, clinical investigation in an urban, university-affiliated hospital. PARTICIPANTS: Sixty patients undergoing elective first-time cardiac surgery were included. INTERVENTIONS: In 30 patients, a standard analgesic regimen was used, and in 30 patients, a PCA regimen was used. The perioperative and postoperative management was similar for all patients. MEASUREMENTS AND MAIN RESULTS: Degree of sedation, satisfaction, and pain (by visual analog scale [VAS]) was assessed within the first 3 postoperative days. Vital capacity (VC) and forced expiratory volume in 1 second (FEV1) were measured using a portable spirometry system. Cortisol and troponin T (TnT) plasma levels were also measured. The expectation of pain was similar in both groups, and the postoperative pain score was significantly lower in the PCA than in the standard group throughout the study period. Significantly more piritramid was used in the PCA (total, 75.6 +/- 33.4 mg) than in the standard group (total, 20.1 +/- 31.9 mg). VC and FEV1 were significantly lower in the standard group compared with the PCA patients. Cortisol and TnT plasma levels were similar in both groups. Frequency of side effects were similar for both groups. CONCLUSION: Because of the beneficial effects with regard to degree of pain and satisfaction, pain management using PCA systems can be recommended for cardiac surgery patients. It appears to be superior to standard nurse-based pain therapy.

[Pseudoaneurysm in the vicinity of the ascending aorta caused by contained disruption at the insertion site of a coronary artery bypass graft. A case report]. / Pseudoaneurysma im Bereich der Aorta ascendens bei gedeckter Perforation am Abgang eines koronaren Venen-Bypasses. Ein Fallbericht.

In this case report a 65-year-old patient came into the emergency ward with acute chest pain after coronary artery bypass graft operation in 1985. On routine chest X-ray in 1995 a mediastinal widening was diagnosed. The chest X-ray in 1997 (Figure 1) showed an increase of the diameter of the known mediastinal widening. Therefore a CT-scan was performed (Figures 2a and 2b). This showed an enhancement of contrast material in a contained structure, without identifying its origin. Therefore a coronary angiography was done. Here, we diagnosed a contained disruption of the aorta at the insertion site of the bypass graft at the right coronary artery. Figure 3a shows leakage of contrast material out of the aorta into the pseudoaneurysm and in Figure 3b this is demonstrated in a schematic drawing. Figure 4a shows supraselective imaging of the pseudoaneurysm, demonstrated in a schematic drawing in Figure 4b. As the chest pain could only be handled by i.v.-medication, betablocker and bed rest we decided to operate. Intra-operatively the diagnosis was confirmed (Figure 5a and 5b). Postoperatively the patient died due to cerebral ischemia. Despite the lethal outcome an operative revision appears even retrospectively justified because of the increasing size of the pseudoaneurysm in addition to new symptoms that were difficult to treat. On the other hand there are no data available in order to estimate the risk of a spontaneous course.

[A comparison of the Arndt endobronchial blocker with a double lumen tube in robotic cardiac surgery]. / Ein Vergleich des Arndt-Bronchusblockers mit einem Doppellumentubus im Rahmen robotergestützter Eingriffe in der Herzchirurgie.

OBJECTIVE: In this prospective, randomised study a double lumen tube (DLT) or an Arndt bronchial blocker (BB) was used for one lung ventilation (OLV). Intraoperative oxygenation, ventilation, haemodynamics, and ease of placement were compared. METHODS: In 32 patients undergoing robotic harvesting of the left internal thoracic artery (ITA) a left-sided DLT or a BB controlled by bronchoscopy was used for OLV of the right lung. In 2 patients randomised for DLT, a single lumen tube and BB was used for difficult visualisation of the larynx. These 2 patients were excluded from the study. RESULTS: Correct placement of DLT (8.8 +/- 5.4 min, 87.5 % of the patients) as well as BB (6.5 +/- 4.0 min; n. s.; 100 % of the patients) was achieved rapidly. The Cormack-Lehane score for visualisation of the larynx was 2, 1 - 3 (median, range) in group DLT and 3, 1 - 4 (median, range) in group BB (p < 0.05). OLV lasted for 93 +/- 29 min in group DLT and 88 +/- 34 min in group BB (n. s.). Satisfactory conditions for harvesting ITA were achieved in all patients of both groups. There was no difference in any haemodynamic parameter at any time between the two groups. Mean pulmonary arterial pressure and pulmonary vascular resistance were increased without significant differences between the two groups during thoracoscopy for robotic preparation of left ITA. During OLV, index of paO (2)/FiO (2) was significantly (p < 0.05) lower in DLT patients compared to BB patients. Time to extubation did not differ between the two groups (DLT 14.3 +/- 4.6 h; BB 11.8 +/- 3.8 h). CONCLUSION: OLV in patients undergoing robotic cardiac surgery was safely achieved either by BB or by left-sided DLT. Positioning of the BB was easier than that of a DLT when intubation was difficult and tube exchange at the end of surgery is avoided. Therefore, we prefer a BB in patients undergoing robotic harvesting of left ITA.

Effect of intravenous dopamine infusion on plasma concentrations of dopamine and dopamine sulfate in men, during and up to 18 h after infusion.

OBJECTIVE: We investigated whether sulfoconjugation contributes to the inactivation of intravenously infused dopamine (DA) in low concentrations with a predominant action on the kidney. METHODS: Plasma DA and dopamine sulfate (DA-S) concentrations were determined during 4 h of intravenous infusion of DA (2 microg/kg/min) and up to 18 h after cessation of infusion. Twenty-seven healthy young subjects participated in the placebo controlled, randomised and double-blind study. RESULTS: Intravenously administered DA was sulfoconjugated rapidly and to a great extent. After starting the infusion, DA levels rose within minutes and reached a steady state after 30-60 min. The steady-state levels averaged 151.3 +/- 8.2 nmol/l. DA-S levels also increased markedly with infusion from 16.7 +/- 9.9 nmol/l at the start of infusion up to 261.2 +/- 24.2 nmol/l at 30 min after cessation of infusion. Plasma DA concentrations after cessation of the infusion decreased rapidly with an initial half-life of elimination of 4.8 min. Concentrations of plasma DA-S declined with a half-life of 4.5 h. Persistent elevations of free and conjugated DA compared with pre-treatment levels were observed even 18 h after cessation. Heart rate and blood pressure remained unchanged both during DA and saline infusion. CONCLUSION: Findings indicate that the sulfoconjugation pathway contributes markedly to the inactivation of intravenously infused DA and seems not to be saturable by DA infusion in low doses.

Influence of a new hydroxyethylstarch preparation (HES 130/0.4) on coagulation in cardiac surgical patients.

OBJECTIVE: To compare volume therapy with HES 130/0.4, a new hydroxyethylstarch (HES) solution with a gelatin-based fluid replacement strategy. DESIGN: Prospective, randomized, safety study. SETTING: Urban, university-affiliated hospital (single institution). PARTICIPANTS: Forty-two patients undergoing elective cardiac surgery. INTERVENTIONS: Patients were prospectively randomized into 2 groups: In group 1 (n = 21), gelatin was given perioperatively for volume support until the 1st postoperative day to keep the central venous pressure (CVP) between 10 and 14 mmHg; in group 2 (n = 21) HES 130/0.4 was administered using the same protocol as in group 1. MEASUREMENTS AND MAIN RESULTS: Standard coagulation variables and modified thromboelastography (TEG) were used. Using different activators for extrinsic and intrinsic activation and heparin inactivation by heparinase, the onset of coagulation (coagulation time), kinetics of clot formation (clot formation time), and maximum clot firmness were measured. Measurements were performed after induction of anesthesia (T0), at the end of surgery (T1), 4 hours after surgery (T2), and on the morning of the 1st postoperative day (T3). A total of 3310 +/- 810 mL of gelatin and 3070 +/- 570 mL of HES 130/0.4 were used in the 2 groups during the study period. The 2 groups did not differ with regard to postoperative bleeding or in use of packed red blood cells or fresh frozen plasma. Standard coagulation variables were similar between the 2 groups. All TEG variables were within the normal range at baseline. Coagulation time and clot formation time data were significantly elevated after surgery and in the intensive care unit, without showing specific differences between the 2 volume replacement groups. Intrinsic TEG and heparinase TEG clot formation times remained significantly higher until the end of the study period. No differences were seen between HES-treated and gelatin-treated patients. CONCLUSIONS: Volume replacement with the new HES preparation was as safe as gelatin-based volume replacement with regard to coagulation in cardiac surgical patients. HES 130/0.4 is an alternative plasma substitute to treat volume deficits.