Browsing by Subject "Ischemia"

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Open Access
The effect of epidural anesthesia on muscle flap tolerance to venous ischemia
(Lippincott Williams & Wilkins, 2010) Cayci, C.; Cinar, C.; Yucel, O. A.; Tekinay, T.; Ascherman, J. A.
Background: Venous ischemia is a major cause of failure after free tissue transfers and replantations. The combination of general and epidural anesthesia leads to vasodilatation and improves tissue perfusion. Postoperative pain relief and sympathetic blockage are additional benefits of epidural anesthesia. The purpose of this study was to determine whether epidural anesthesia has benefits on microcirculation and neutrophil functions in muscle flaps subjected to venous ischemia. Method: Thirty Sprague-Dawley rats were divided into three groups: group I, general anesthesia; group II, spinal anesthesia; and group III, epidural anesthesia. Cremaster flaps were prepared, postcapillary venules were selected under intravital videomicroscopy, and flaps were subjected to venous ischemia. Images were recorded from preselected postcapillary venules before venous ischemia (baseline) and following reperfusion. Neutrophil rolling and adhesion, functional capillary density, and diameters of postcapillary venules were evaluated. Results: The increase in rolling neutrophils in group III was significantly lower than in groups I and II at 60 and 120 minutes. Change of adherent neutrophils in group III was significantly lower than in groups I and II at 15, 60 and 120 minutes. There was significantly more reduction in inner diameter of postcapillary venules in groups I and II compared with group III. Functional capillary density in groups I and II was significantly lower than in group III. Conclusion: Epidural anesthesia regulated neutrophil functions, salvaged functional capillaries, and prevented vasoconstriction of postcapillary venules in cremaster muscle flaps subjected to venous ischemia. Spinal and general anesthesia, however, were found to be ineffective in improving microcirculation of muscle flaps subjected to venous ischemia.
Open Access
Significance of QT dispersion as a diagnosis tool for cardiac patients
(2000) Ben Ahmed Jemel, Nabil
Electrocardiogram (EGG) is the recorded electrical potentials generated by the heart during a cardiac cycle. Gardiac abnormalities cause unknown current flows leading to strange waveform morphologies in the recorded EGG. Some of these abnormalities are only visible when the heart is under stress. Exercise EGG is conducted for this reason. Ischemia is one of the important cardiac abnormalities and is the focus of our study. It occurs when a part of the heart tissue dies or is injured. QT dispersion (QTd) is a proposed method for diagnosing Ischemia. The classical deflnition for QTd is the difference between the maximum and the minimum QT intervals within the 12 leads. In this study the effect of exercise on QT dispersion (QTd) is studied and whether QTd could give significant information for diagnosing patients with ischemic heart disease is investigated. A new method for measuring QT interval is developed and is compared with previous methods. QTd is measured on average beats calculated for 10 seconds intervals throughout the exercise ECG test and a trend curve which we call QTd, is generated. Several decision rules for the diagnosis of cardiac patients are proposed by analyzing these QTd trend curves and the accompanying heart rate curves. It is shown that despite the improvement in QT interval measurements, none of the decision rules proved to be a clinically useful discriminate of cardiac patients, with sufficient confidence.