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  • 1
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Hyperglykämie ; Hypoglykämie ; regionale Organdurchblutung ; Microspheres ; kardiopulmonale Reanimation (CPR) ; Key words Hyperglycaemia ; Hypoglycaemia ; Regional organ blood flow ; Microspheres ; Cardiopulmonary resuscitation (CPR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Blood glucose alterations prior to cerebral ischaemia are associated with poor neurologic outcome, possibly due to extensive lactic acidosis or energy failure. Cerebral effects of hyper- or hypoglycaemia during cardiopulmonary resuscitation (CPR) are less well known. In addition, little information is available concerning cardiac effects of blood glucose alterations. The aim of this study was to evaluate the effects of pre-cardiac-arrest hypo- or hyperglycaemia compared to normoglycaemia upon haemodynamics, cerebral blood flow (CBF) and metabolism (CMRO2), and regional cardiac blood flow during CPR subsequent to 3 min of cardiac and respiratory arrest and after restoration of spontaneous circulation. Methods. After approval by the State Animal Investigation Committee, 29 mechanically ventilated, anaesthetised pigs were instrumented for haemodynamic monitoring and blood flow determination by the radiolabeled microsphere technique. The animals were randomly assigned to one of three groups: in group I (n=9) blood glucose was not manipulated; in group II (n=10) blood glucose was increased by slow infusion of 40% glucose to 319±13 mg/dl; in group III (n=10) blood glucose was lowered by careful titration with insulin to 34±2 mg/dl. After 3 min of untreated ventricular fibrillation and respiratory arrest, CPR (chest compressor/ventilator (Thumper®) and epinephrine infusion) was commenced and continued for 8 min. Thereafter, defibrillation was attempted, and if successful, the animals were observed for another 240 min. Cerebral perfusion pressure (CPP), CBF, CMRO2, coronary perfusion pressure (CorPP), and regional cardiac blood flow were determined at control, after 3 min of CPR, and at 10, 30, and 240 min post-CPR. Results. In group I, 4/9 animals (44%) could be successfully resuscitated; in group II 4/10 (40%); and in group III 0/10 (0%). Prior to cardiac arrest, mean arterial pressure, CPP, and CorPP in group III were significantly lower compared to groups I and II. In group I, CPP during CPR was 26±6 mmHg; CBF 31±9 ml/min/100 g CMRO2 3.8±1.2 ml/min/100 g; CorPP 18±5 mmHg; and left ventricular (LV) flow 35±15 ml/min/100 g. In group II: CPP=21±5; CBF 21±7; CMRO2 1.8±0.8; CorPP 16±6; and LV flow 22±9; and in group III: CPP 15±3; CBF 11±8; CMRO2 1.5±1.1; CorPP 4±2; and LV flow 19±10. During the 240-min post-resuscitation period, there were no differences in CBF, CMRO2, or LV flow between groups I and II. Conclusion. Hypoglycaemia prior to cardiac arrest appears to be predictive for a poor cardiac outcome, whereas hyperglycaemia does not impair resuscitability compared to normoglycaemia. In addition, hyperglycaemia did not affect LV flow, CBF, or CMRO2. However, it has to be kept in mind that haemodynamics and organ blood flow do not permit conclusions with respect to functional neurologic recovery or histopathologic damage to the brain, which is very likely to be associated with hyperglycaemia.
    Notes: Zusammenfassung Gegenstand der vorliegenden Untersuchung im Schweinemodell ist der Einfluß einer prä-ischämischen Normo-, Hyper- oder Hypoglykämie auf Hämodynamik, regionale Organdurchblutung und Reanimierbarkeit nach 3minüti-gem unbehandelten Herz-Kreislauf-Stillstand und anschließender kardiopulmonalen Reanimation (CPR). Hypoglykämie (Blutzuckerkonzentration von 34±2 mg/dl) war bereits vor der Reanimation mit einer deutlichen Beeinträchtigung hämodynamischer Parameter assoziiert. Keines der hypoglykämischen Tiere konnte erfolgreich reanimiert werden, im Gegensatz zu den hyper- (Blutzucker 319±13 mg/dl) bzw. normoglykämischen Tieren, die keinen Unterschied hinsichtlich der Erfolgsrate der Reanimation aufwiesen. Weder vor noch während oder nach Reanimation unterschieden sich hyper- und normoglykämische Tiere in bezug auf Hämodynamik oder regionale kardiale oder zerebrale Durchblutung. Somit bleibt festzuhalten, daß Hypoglykämie bei CPR mit einer schlechten kardialen Prognose assoziiert ist, während Hyperglykämie die kardiale Reanimation offenbar nicht beeinträchtigt.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Dental traumatology 11 (1995), S. 0 
    ISSN: 1600-0595
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract - A case of a transdental fixation planned on the basis of ultrafast computed tomography is reported. This method allows to gain an insight in the osseous structures required for the operative procedure. Ultrafast computed tomography is superior to the convential radiographs in obtaining accurate information about the vertical bone supply and the extension of the facial osseous sinus wall. A set of axial CT-images with an extension of 3 mm was acquired in the region of the alveolar bone. By means of frontal reconstructions and data processing methods the thickness of the bone layer in transverse direction was accurately determined. The calculated bone thickness allowed to anchor a transdental self-tapping titanium screw.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1435-1285
    Keywords: Key words Carvedilol – autonomic nervous system – idiopathic dilated cardiomyopathy ; Schlüsselwörter Carvedilol – autonomes Nervensystem – dilatative Kardiomyopathie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der vorliegenden prospektiven Studie wurde 14 Patienten mit dilatativer Kardiomyopathie (DCM) zusätzlich zu einer konventionellen Basistherapie bestehend aus Digitalis, Diuretika und ACE-Hemmern Carvedilol einschleichend bis zu einer maximalen Dosierung von 25–50mg/Tag verabreicht. Zu Beginn und nach 8 Wochen Therapie mit Carvedilol wurden aus digitalen 24-h-Langkeit-EKG-Registrierungen mittels des Oxford™ Medilog Excel 2 Analysesystems folgende Zeitbereichsparameter der Herzfrequenzvariabilität (HRV) bestimmt: RRm=Mittelwert aller normalen Kopplungsintervalle (NN), SDNN=Standardabweichung aller NNs, rMSSD=Quadratwurzel des quadratischen Mittelwertes der Differenzen aufeinanderfolgender NNs und pNN50=Anteil aller aufeinanderfolgenden NNs, die sich mehr als 50ms unterscheiden. Zusätzlich wurden vor und unter der Carvediloltherapie echokardiographische Untersuchungen durchgeführt sowie ein klinischer Status der Studienpatienten erhoben. Unter der additiven Gabe von Carvedilol besserten sich alle Zeitbereichsparameter der HRV signifikant: SDNN stieg unter Carvedilol von 77±21 auf 110±22ms (p=0,0001), rMSSD von 19±7 auf 26±7ms (p=0,02) und der mittlere pNN50-Wert von initial 1,7±1,3 auf 5,5±4,5% (p〈0,01) an. Die über 24h gemittelte Herzfrequenz sank um 13 Schläge/min von zu Beginn 88±10 Schläge/min auf 75±10 Schläge/min (p〈0,01). Die linksventrikuläre Auswurffraktion stieg von initial 24±7% auf 30±10% (p〈0,05) unter Carvedilol an. Die mittlere NYHA-Klasse besserte sich unter Carvedilol von 2,5±0,8 auf 1,8±0,7 (p〈0,05). Zusammenfassend verbesserte die additive Therapie mit Carvedilol sowohl die Herzfrequenzvariabilität als auch echokardiographische und klinische Parameter bei Patienten mit dilatativer Kardiomyopathie.
    Notes: Summary The aim of the present study was to assess the effects of carvedilol therapy in addition to conventional heart failure therapy on heart rate variability (HRV) and on left ventricular function in 14 patients with mild to moderate heart failure due to idiopathic dilated cardiomyopathy (IDC). After a 3- to 4-week titration period, carvedilol was titrated up to 50mg daily, or the highest dose tolerated (at least 25mg daily). Maintenance treatment was then continued for 8 weeks. Digital 24-hour Holter recordings were obtained at baseline and after 8 weeks of carvedilol therapy. HRV for the entire 24-hour period was computed in the time domain using the Oxford Medilog Excel 2 analysis system. Measures of HRV included the mean of all coupling intervals between normal beats (RRm), the standard deviation of all normal RR intervals (SDNN), the square root of the mean of the squared differences between adjacent normal RR intervals (rMSSD), and the proportion of adjacent normal RR intervals differing 〉50ms (pNN50). Additional treatment with carvedilol induced a significant increase in HRV: SDNN increased from 77±21ms to 110±22ms (p=0.001), rMSSD from 19±7ms to 26±7ms (p=0.02), and mean pNN50-value increased from 1.7±1.3% to 5.5±4.5% (p〈0.01) under therapy with carvedilol. Mean heart rate on carvedilol calculated over 24 hours was 13 beats less than at baseline (75 bpm versus 88 bpm, p〈0.01). After 2 months of additional treatment with carvedilol, both hemodynamic and clinical parameters improved: left ventricular ejection fraction increased from 24±7% to 30±10% (p〈0.05), and New York Heart Association class decreased from 2.5±0.8 to 1.8±0.7 (p〈0.05). In summary, eight weeks of additional carvedilol therapy induced a significant increase in HRV parameters related to parasympathetic activity in patients with IDC. Whether increased vagal tone may contribute to the protective effect of carvedilol has to be evaluated by further studies.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Der Internist 38 (1997), S. 742-746 
    ISSN: 1432-1289
    Keywords: Schlüsselwörter Langzeit-EKG ; Herzfrequenzvariabilität ; Herzrhythmusstörung ; Diagnostik KHK
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zum Thema Langzeit-EKG Registrierungen wurden in den vergangenen 35 Jahren unverzichtbar bei Diagnostik und Therapiekontrolle bradykarder und tachykarder Rhythmusstörungen aller Art. Durch die Entwicklung leistungsfähiger Computer mit entsprechender Software verfügen praktisch alle modernen Langzeit-EKG Auswertesysteme über die Möglichkeit der Herzfrequenzanalyse als Indikator des kardialen autonomen Tonus. Patienten mit struktureller Herzerkrankung haben verglichen mit Herzgesunden eine mehr oder weniger veränderte Herzfrequenzvariabilität mit Abnahme der respiratorischen Sinusarrhythmie und Verminderung oder Fehlen der vagusbedingten, nächtlichen Herzfrequenzabnahme. Bei Patienten nach Myokardinfarkt ist inzwischen der Zusammenhang zwischen einer deutlich verminderten Herzfrequenzvariabilität im Langzeit-EKG als Marker für einen reduzierten kardialen Vagustonus und einer signifikant erhöhten Mortalität belegt. Die vorliegende Übersicht faßt die Bedeutung von Langzeit-EKG Registrierungen für die Innere Medizin zusammen und gibt eine kritische Wertung zu Indikation und Interpretation von Langzeit-EKGs sowie zu therapeutischen Konsequenzen pathologischer Langzeit-EKG Befunde.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of optimization theory and applications 92 (1997), S. 263-283 
    ISSN: 1573-2878
    Keywords: Optimal control problems ; multiple shooting methods ; direct methods ; indirect methods ; adjoint variables
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract To solve the multipoint boundary-value problem (MPBVP) associated with a constrained optimal control problem, one needs a good guess not only for the state but also for the costate variables. A direct multiple shooting method is described, which yields approximations of the optimal state and control histories. The Kuhn–Tucker conditions for the optimal parametric control are rewritten using adjoint variables. From this representation, estimates for the adjoint variables at the multiple shooting nodes are derived. The estimates are proved to be consistent, in the sense that they converge toward the MPBVP solution if the parametrization is refined. An optimal aircraft maneuver demonstrates the transition from the direct to the indirect method.
    Type of Medium: Electronic Resource
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