Robert Pucher

Prognosis after acute subdural or epidural haemorrhage

SummaryIn a series of 171 patients suffering acute subdural haemorrhage (SDH) (111 patients) or epidural haemorrhage (EDH) (60 patients) after closed head injury accumulated during the years 1978–1985 at the University Hospital of Graz, the mortality rate and the grade of clinical recovery were evaluated. The overall mortality in acute SDH was 57%, in acute EDH 25%, the percentages of good recoveries—full recovery and minimal neurologic deficit—25 and 58%, respectively. Outcome was found to be predominantly influenced by the preoperative state of consciousness, associated brain lesions, and, in comatose patients, the duration of the time interval between onset of coma and surgical decompression. When this interval exceeded two hours, mortality from SDH rose from 47 to 80% (good outcomes 32 and 4%, respectively). In acute EDH an interval under two hours lead to 17% mortality and 67% of good recoveries compared to 65% mortality and 13% of good recoveries after an interval of more than two hours. Age and concomitant injuries of other body regions proved to be of secondary importance.

Cerebrovascular response to intracranial hypertension

SummaryPial arterial and venous calibre changes during intracranial hypertension were studied in 11 cats under barbiturate- and nitrous oxide-anaesthesia by using a closed cranial window technique and multichannel videoangiometry. Intracranial pressure was elevated from a normal mean level of 6.4 mm Hg by cisternal infusion of mock CSF in steps to 20, 30, 40, 50 mm Hg and finally to the level of systolic pressure. Pial arteries dilated significantly, small ones more than large ones, by 42±5.6% and 33±3%, respectively at ICP 50. With a further elevation of ICP up to systolic pressure, dilatation diminished to 28±10% in small, and to near resting calibres in large arteries. Pial veins remained unreactive on the average. Grouping into veins smaller and larger than 100 μm of resting size revealed, however, minor though statistically significant 5–10% dilatation of small, and a 5–10% diminution of large veins. Blood flow stopped, when cerebral perfusion pressure was zero, however, neither arteries nor veins collapsed.The present data support the hypothesis that CBF during acute elevation of CSF pressure depends on perfusion pressure rather than local vascular compression.

How to motivate students in project based learning

Educational thinking in higher education has undergone a rapid change. The ability to remember facts loses importance whereas the capability to solve problems becomes more and more the main focus of teaching. At the Technikum Wien Project Based Learning (PBL) was introduced in various subjects of our IT course. The basic approach of PBL originated from the University of Maastricht in the Netherlands where it is reported to be highly successful. The specific problem the authors tried to solve, deals with the motivation of students. The main motivation of students is-of course-to achieve good test results and only the lesser focus lies on the specific contents of the subject. The authors tried to develop a method, which allows the students to focus their intrinsic motivation onto the study project itself and not onto the extrinsic motivation, namely test results.

Effects of vasospasm in the middle cerebral artery territory on flow velocity and volume flow. A computersimulation.

SummaryRecently blood flow velocity in large cerebral arteries became measurable non-invasively by transcranial Doppler sonography (TCD). The present study tries to quantify the relation between flow velocity and the more important volume flow in the middle cerebral artery (MCA) by means of Computersimulation. A mathematical model of the MCA territory was developed. The model is able to take into account the non-Newtonian behaviour of blood viscosity and is also able to handle turbulant and laminar flow. Autoregulation is simulated by increasing or decreasing diameter of arteries as an answer to intraluminal pressure changes. Two processes are simulated: Vasospasm in the stem of the MCA, and vasospasm in the entire MCA territory. Results show that the relation between flow velocity and volume flow is rather complicated. Vasospasm in the MCA stem first leads to an increase of flow velocity at a constant level of volume flow. At higher grades of vessel constriction volume flow and flow velocity start to fall.

Autoregulatory response of pial vessels in the cat

Pial vessel responses to mean arterial pressures (MAP) between 40 and 160 mmHg, induced by withdrawal and reinfusion of blood, were studied in twelve cats under barbiturate- and N2O-anaesthesia, using the cranial window technique and videoangiometry. Very minor changes of pial arterial calibres were noted between MAP 80 and 120 mmHg. During further reduction of MAP, small arteries dilated more than large arteries and measured 43 +/- 4.6% and 30 +/- 1.9% at MAP 40 mmHg, respectively. When MAP was elevated to 140 mmHg, large arteries constricted more than small ones; at MAP 160 mmHg, however, they started to redilate, while small arteries continued to constrict to -13 +/- 2.3%. Within the autoregulatory range, pial veins remained unchanged; at MAPs of 40 and 160 mmHg, venous calibre variations remained below 10%.

Über Trifurkationen der Arteria cerebri media

The furcation types of 100 human middle cerebral arteries (MCA) were investigated. Considering the physiological flow characteristics in furcations, a distinct definition for a bifurcation and a trifurcation was found. The common ramification type of the human MCA is the bifurcation. Trifurcations are very rare and we found them only in the proximal parts of the MCA. In 7 of the 100 cases a trifurcation was found at the main division of the MCA in 3 cases a secondary trunk trifurcated. Quadro- and pentafurcations according to the hydrodynamic definitions were not observed at all. Only in 1 case did the internal carotid artery trif urcate into the anterior cerebral artery a superior trunk and an inferior trunk of the MCA.

Ein Beitrag zur Hirndurchblutung des Menschen unhand von Gefässausgüssen des Karotissystems

20 corrosion casts of human anterior cerebral arteries and middle cerebral arteries were analyzed. In 588 vessel sections in between 2 bifurcations, the relation of vessel length and vessel diameter was investigated. Measurements were taken starting from the arterial trunk down to vessels with a diameter of 0.4 mm. The mean values of the lengths show that both the anterior cerebral artery and the middle cerebral artery can be grouped into 5 diameter ranges with significant different lengths. With decreasing diameter there are short vessels in the groups 1, 3 and 5 and long vessels in the groups 2 and 4. However, the long branches in the groups 2 and 4 of the middle cerebral artery are longer and thinner than in the anterior cerebral artery. Due to the higher pressure loss in thin and long vessels, blood pressure drop occurs earlier in the branches of the middle cerebral artery than in those of the anterior cerebral artery.

Surgical treatment of cerebrovascular occlusive disease. A follow-up study

SummaryThis prospective open study of 124 patients [80% with completed stroke (CS), 16% with TIAS, 4% with PRIND] consecutively admitted between 1976 and 1981 investigates the rates of reinfarction after surgical treatment (extra-intracranial arterial bypass, EIAB and/or carotid thrombendarterectomy, TEA). 34% of patients had unilateral carotid stenosis, 26% unilateral internal carotid artery occlusion, 17% had occlusion of one and stenosis of the contralateral internal carotid artery, 14% bilateral carotid stenosis. Combined surgical morbidity and mortality was 5% after 158 operations in 124 patients; 7 of the 8 complications occurred in patients with CS.Of the 120 survivors in the immediate postoperative period, after a mean follow-up period of 5.7 years ranging from 3–8 years, an infarct occurred in 5.8%,i.e., 1% per year; 3 of them occurred ipsilaterally, 2 contralaterally to the first infarct, two remained unknown. Among all 99 patients with CS, the reinfarction rate was 5% (1% per year); in CS patients with a minimal follow-up of 5 years, the annual reinfarction rate was 2%. Of fifty-three patients with completed stroke after EIAB with a mean follow-up of 4.6 years, 3.8% suffered reinfarction (0.8% per year). Among 26 patients with CS and unilateral carotid occlusion after a mean follow-up of 4.7 years, the reinfarction rate was 3.9% (0.8% per year). Among 46 patients with carotid occlusion with or without further stenotic or occlusive lesions, the reinfarction rate was 2.2%.Comparing these follow-up data with results of medical treatment, it is concluded that a combination of surgical treatment and the administration of acetylsalicylic acid can be considered to improve the prognosis of patients with occlusive and/or stenotic cerebrovascular disease.

Effects of Introducing a Game-Based Student Response System into a Flipped, Person-Centered Classroom on Object-Oriented Design

Gamification and flipped classrooms are popular concepts in the educational sector, especially in engineering education. We introduced the gamified student response system Kahoot! to a flipped undergraduate computer science course on object-oriented design. The 25 students took part in interactive quizzes during class. Data was collected from nine quizzes consisting of 227 questions, six surveys, as well as a final course feedback.

Peer Review as a Tool for Person-Centered Learning: Computer Science Education at Secondary School Level

Using peer assessment in the classroom in order to increase student engagement by actively involving them in the assessment process has been practiced and researched for decades. The literature suggests using peer review for project-based exercises. This paper analyzes the applicability of peer assessment to smaller exercises at secondary school level and makes recommendations for its use in computer science courses. For this purpose, two secondary school classes consisting of a total of 57 students were introduced to the peer assessment method within the scope of the same software engineering course. Two of 13 exercises were assessed using peer reviews via the Moodle workshop activity. The students were asked to evaluate these two exercises using an anonymous online questionnaire. At the end of the course, they were asked to rate all of the 13 exercises regarding their motivation to learn.