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Cardiovascular Hemodynamics (cardiovascular + hemodynamic)
Selected AbstractsEXAMINATION OF RESPIRATORY AND CIRCULATORY DYNAMICS DURING EXAMINATION USING A THIN GASTROINTESTINAL ENDOSCOPE IN ADVANCED-AGE SUBJECTSDIGESTIVE ENDOSCOPY, Issue 2 2007Miyako Niki Background:, Endoscopic examination influences cardiovascular hemodynamics. Upper gastrointestinal examinations are currently performed with a thin endoscope. In the present study, respiratory and circulatory dynamics and autonomic nervous activity using a thin endoscope (XP260) or a standard endoscope (XQ240) were investigated. Methods:, The subjects were 25 healthy adults aged less than 60 years (middle-aged group) and 15 healthy adults aged 60 years or older (advanced-age group). Percutaneous oxygen saturation, tonometric blood pressure, heart rate, and autonomic nervous activity were evaluated before the examination. After the endoscopic procedure, a questionnaire survey regarding examination-related stress was conducted. Results:, In the questionnaire survey, the proportion of subjects who answered ,very stress free' in the thin endoscope group was significantly higher than that in the standard endoscope group. The low frequency power of blood pressure variability (LFBP), an indicator of sympathetic nervous activity, was significantly lower during the thin endoscopic procedure than during the standard endoscopic procedure. Moreover, the ratio of low frequency power to high frequency power of heart rate variability (LFRR/HFRR), an indicator of sympathetic nervous activity, was significantly lower during thin endoscopic procedure than during the standard endoscopic procedure. The maximum rates of change in the LFBP and HFRR powers in the advanced-age group using thin and standard endoscopic procedures were significantly lower than in the middle-aged group. Conclusions:, The findings, although not in cross-over study, suggest that a thin endoscope has a less marked influence on circulatory kinetics. Gastrointestinal endoscopic examinations using a thin endoscope might reduce complications related to endoscopic screening examinations in advanced-age subjects. [source] Divergent effects of ephedrine and phenylephrine on cardiovascular hemodynamics of near-term fetal sheep exposed to hypoxemia and maternal hypotensionACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2007T. Erkinaro Background:, We hypothesized that the administration of ephedrine and phenylephrine for maternal hypotension modifies cardiovascular hemodynamics in near-term sheep fetuses. Methods:, At 115,136 days of gestation, chronically instrumented, anesthetized ewes with either normal placental function or increased placental vascular resistance after placental embolization were randomized to receive boluses of ephedrine (n = 12) or phenylephrine (n = 12) for epidural-induced hypotension after a short period of hypoxemia. Fetal cardiovascular hemodynamics were assessed by Doppler ultrasonography at baseline, during hypotension and after vasopressor treatment. Results:, During hypotension, fetal PO2 decreased and proximal branch pulmonary arterial and pulmonary venous vascular impedances increased. Additionally, in the embolized fetuses, the time-velocity integral ratio between the antegrade and retrograde blood flow components of the aortic isthmus decreased. These parameters were restored to baseline conditions by ephedrine but not by phenylephrine. With phenylephrine, weight-indexed left ventricular cardiac output and ejection force decreased in the non-embolized fetuses, and the proportion of isovolumetric contraction time of the total cardiac cycle was elevated in the embolized fetuses. Conclusions:, After exposure to hypoxemia and maternal hypotension, ephedrine restored all fetal cardiovascular hemodynamic parameters to baseline. Phenylephrine did not reverse fetal pulmonary vasoconstriction or the relative decrease in the net forward flow through the aortic isthmus observed in fetuses with increased placental vascular resistance. Moreover, fetal left ventricular function was impaired during phenylephrine administration. [source] | ||||||||||