Parallel optical trap assisted nanopatterning on rough surfaces.

There exist many optical lithography techniques for generating nanostructures on hard, flat surfaces over large areas. However, few techniques are able to create such patterns on soft materials or surfaces with pre-existing structure. To address this need, we demonstrate the use of parallel optical trap assisted nanopatterning (OTAN) to provide an efficient and robust direct-write method of producing nanoscale features without the need for focal plane adjustment. Parallel patterning on model surfaces of polyimide with vertical steps greater than 1.5 µm shows a feature size uncertainty better than 4% across the step and lateral positional accuracy of 25 nm. A Brownian motion model is used to describe the positional accuracy enabling one to predict how variation in system parameters will affect the nanopatterning results. These combined results suggest that OTAN is a viable technique for massively parallel direct-write nanolithography on non-traditional surfaces.

A new sternal retraction device for the dissection of the internal mammary artery.

For the dissection of the internal mammary artery (IMA), we use a new sternal retraction technique. The retractor is an angled stainless steel device with a slotted face and two sternal arresting hooks. The method is simple and the device acts as a unit with a standard sternal spreader. The time period between mounting and the exposure of the IMA is only a few seconds. The entire procedure takes place in the sterile operative field. By utilizing this method, we dissected nearly 300 IMAs without any complications or serious sternal injuries.

[Embolization of a Mobin-Uddin filter]. / Embolisation eines Mobin-Uddin-Filters.

A case of Mobin-Uddin-Filter embolisation (28 mm filter) into the right pulmonary artery is presented. Via a right thoracotomy filter and thrombi could easily be extracted. Indication, avoidance of malposition, and the question of whether the filter should be extracted after embolisation are discussed.

[Accidental drowning with extreme hypothermia--rewarming with extracorporeal circulation]. / Unfall durch Ertrinken mit extremer Unterkühlung--Wiedererwärmung mittels extracorporaler Zirkulation.

A 3 1/2 year old boy had fallen into a fishpond. After about one hour the boy was brought to our hospital. He was cyanotic and bloated, the rectal temperature was 18.4 degrees C. There was no heart beat, the pupils were wide without reaction to light. Via a sternotomy the heart lung machine was connected and core rewarming was achieved. After 7 days of artificial respiration the boy could be extubated, after 16 days the boy left our hospital without neurological consequences.

[Perspectives in applying guidelines]. / Perspektiven im Umgang mit Leitlinien.

Definition, purpose and future fate of guidelines are presented. Special stress is placed on the fact that guidelines represent a tool for rationalization by which economical capacities are activated and rationing is prevented.

[Acute pulmonary embolism--are vena cava interruption procedures and extracorporeal circulation always necessary?]. / Die akute Lungenarterienembolie--sind Cavasperroperationen und extrakorporale Zirkulation immer notwendig?

Between 1983 und 1991, emergency pulmonary embolectomy with the aid of extracorporeal circulation was performed in 13 patients. Ten patients were in class IV according to Greenfield, seven came into the operating theater with external cardiac massage. The 30-day mortality was 46%. In the same period, 15 venous interruption procedures were performed (three Adams de Weese Clip, ten Greenfield-Filter, and two femoral vein ligations). Eight times the venous interruption procedure was done prophylactically. The acute pulmonary embolism of class III and IV according to Greenfield is an indication for lytic therapy. We operate only if there is a contraindication to lytic therapy or if there is deterioration of the clinical state.

[Retroperitoneal vascular injuries (author's transl)]. / Retroperitoneale Gefässverletzungen.

From 1973-1977, 21 retroperitoneal vascular injuries were seen at the Medical School of Hannover. Vascular lesions of polytraumatized patients were treated 12 times. The rest were iatrogenic traumas after laminectomy, herniotomy, and hip replacement as well as after urologic and gynecologic operations. The overall mortality was 43%. Surgical treatment of the different vascular regions is discussed.

[Whole body oxygen uptake in coronary artery bypass surgery (author's transl)]. / Uberwachung der Gesamtsauerstoffaufnahme bei koronarchirurgischen Eingriffen.

In 10 patients who underwent aorto-coronary bypass operations haemodynamic parameters and whole body oxygen uptake were monitored, beginning after induction of anaesthesia, during extracorporeal circulation and the postoperative period up to 5 h. In the intensive care unit a new device for the continuous measurement of whole body oxygen uptake from expired gases was used. For anaesthesia constant doses of fentanyl (10 micrograms/kg/h) and nitrous oxide were given. These were supplemented by low concentrations of halothane and nitroglycerine if hypertension occurred. Before extracorporeal circulation hypertensive states were observed in 8 cases and were effectively controlled without compromising tissue oxygenation. During extracorporeal circulation oxygen consumption was reduced more than could be explained only by the effects of hypothermia, indicating a limited shock state. Within the first postoperative hour the total peripheral resistance increased more than during the whole operation, impairing cardiac function at low levels of oxygen uptake. Thereafter a rise in metabolism was seen, partially induced by shivering which led to a marked (235% of control) increase in whole body oxygen uptake. This was accompanied by a reduction of the total peripheral resistance and an improvement of cardiac function. No acidosis was observed. Artificial ventilation is mandatory until metabolic demands have normalized. Noninvasive continuous monitoring of whole body oxygen uptake was useful for the assessment of cardiovascular function, increased postoperative metabolic demands, early detection of hypovolaemia and weaning from artificial ventilation.

Surgical correction of an atherosclerotic coronary artery aneurysm. Case report.

A 56-year-old male patient became symptomatic with angina pectoris. Selective coronary angiography revealed an aneurysm of the stem of the circumflex artery and a subtotal stenosis of the left anterior descending coronary artery (LAD). At cardiac surgery the anterior wall of the aneurysm was resected and the resulting defect closed with a venous patch. Bypass grafts to the LAD and the first marginal branch were also implanted. Three months later both grafts were shown to be patent, and flow through the reconstructed stem of the circumflex artery was undisturbed.

Thermographic evaluation of myocardial temperature during infusion of cold cardioplegia.

Delay in myocardial cooling during an infusion of cold cardioplegic solution may occur in patients with coronary artery disease. Forty patients with significant stenosis of the left anterior descending coronary artery (LAD) were divided into 3 groups according to the extent of the LAD stenosis. Group A consisted of 12 patients with 70% stenosis. Group B included 23 patients with 90% stenosis, and in group C there were 5 patients with LAD occlusion. Myocardial temperature was measured with a thermocamera during infusion of 2000 ml 8 to 10 degrees C cold Bretschneider's cardioplegic solution and compared to 10 other patients without coronary artery disease undergoing mitral valve replacement (group D). In group A the myocardium cooled to 15 degrees C after 4 1/2 minutes and to 12 degrees C after 10 minutes. In group B the myocardial temperature was 15 degrees C after 5 minutes and 12 degrees C after 10 minutes. In group C the temperature reached 18 degrees C after 5 minutes and 14 degrees C after 10 minutes. In group D the myocardial temperature was 12 degrees C after 3 minutes and 10 degrees C after 7 minutes. This study shows far better myocardial cooling rates in patients with unobstructed coronary arteries.

Use of the left internal thoracic artery to correct a left main coronary atresia.

Dyspnea with a slightly enlarged heart was noticed in a five year old girl at a checkup. The cardiological investigation revealed an enlarged left ventricle with slight mitral regurgitation. The right coronary artery was enlarged and filled the entire left arterial system via collaterals. The left main coronary artery could not be detected. In addition, outflow of contrast medium into the large vessels was absent. With the diagnosis of left main coronary atresia, the left internal thoracic artery was implanted on to the proximal left anterior descendent in October 1985. In the control angiogram, the anastomosis conditions were normal, the left ventricle had decreased in size and contracted almost normally. The collaterals from the right could no longer be demonstrated. The child (now six years old) has full exercise tolerance today. In the ultrasonogram, the ventricle shows normal contraction behavior. Up to know, four cases with congenital main coronary atresia have been reported in the literature.

[Use of the mammary artery in coronary revascularization]. / Verwendung der Arteria mammaria zur Coronarrevascularisation.

From August 1983 through December 1985 1088 patients underwent coronary surgery. 406 (37%) received a single or bilateral internal mammary artery (IMA) graft with single or sequential anastomoses. The youngest patient was 6 years old, the oldest 75, with a mean age of 55.7 years. A total of 672 IMA anastomoses was constructed. In addition 348 patients received 610 saphenous vein grafts. 83% of the IMA were anastomosed to the LAD and its branches, 12% to the circumflex and 5% to the right coronary artery. 4 patients (0.98%) died postoperatively, 402 survived and are free of angina. In our experience the IMA can be used routinely with low operative risk and good results.

[Vascular complications following alloplastic hip replacement (author's transl)]. / Gefässkomplikationen beim alloplastischen Hüftgelenkersatz

Two patients with complications of the pelvic vessels have been seen at our institution after total hip replacement. One had a false aneurysmn of the deep femoral artery, the other presented an arterio-venous fistula. Causes, symptomes and diagnosis of vascular complications during hip replacement are reviewed.

[Paraplegia following acute infrarenal aortic occlusion (author's transl)]. / Rückenmarksschädigung beim hohen Aortenverschluss

The clinical syndrome of paraplegia following acute occlusion of the infrarenal aorta may be caused by either ischemic spinal cord damage or ischemia of the cauda equina and sacral nerve roots and ganglia. The neurologic manifestations are similar and therefore specific anatomic diagnosis is difficult. From October 1972 to February 1975 a total of 31 patients with infrarenal aortic occlusion were treated at the Medizinische Hochschule in Hannover. In nine cases the occlusion up to the renal arteries was acute. Three of these patients presented beside acute ischemic manifestations on both legs and the lower abdominal wall, neurologic symptoms of paraplegia. The anatomic and hemodynamic aspects of ischemic spinal cord damage and those of ischemic lesions of the cauda equina and peripheral nerves are discussed. There appear to be three main mechanisms responsible for vascular paraplegia following acute infrarenal occlusion of the aorta: 1. it may be caused by thrombotic occlusion of a major radicular artery which arises below the level of occlusion. 2. it may be produced by thrombosis of a lumbar collateral acting as major supply to the cord when arteriosclerotic narrowing of the major radicular artery is present. Especially in states of severe hypotension critical interference of blood supply to the spinal cord will result. 3. Paraplegia by ischemia of the cauda and peripheral nervous tissue may also follow prolonged interruption of circulation to this area supplying spinal vessels from low lumbar and sacral arteries.