Effects of reflex circulatory regulation on cardiac morbidity and mortality: influences of gender and menstrual cycle

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(1) Effects of gender and menstrual cycle on cardiovagal baroreflex function We examined cardiovagal baroreflex responses using Neck-Chamber method in 14 healthy female subjects during the early follicular, pre-ovulation and mid-luteal phases, and compared the results with healthy male subjects. We found that (1) baaroreflex sensitivities during the early follicular and mid-luteal phases were less than male volunteers, while that of the pre-ovulation phase was similar to that of male subjects. In addition, plasma estradiol concentration was correlated positively with cardovagal baroreflex sensitivity in female subjects.(2) Effects of gender on cardiovagal baroreflex function before and during general anesthesia Cardiovagal baroreflex responses using the Neck-Chamber method and heart rate variability using the fast Fourier transformation were determined in 15 healthy female subjects irrespective of the menstrual cycle, and compared the results with those of male volunteers. We have foun … More d that baroreflex sensitivity and various indices of heart rate variability, such as SDNN, pNN50 and RMSSD, were all greater in male than female subjects in awake and sevoflurane-anesthetized states.(3) Effects if α2-adrenergic agonist on cardiovagal baroreflex function during and after general anesthesia Effects of α2-adrenergic agonist, dex-medetomidine 25 μg/kg iv, on cardiovagal baroreflex responses by the Neck-Chamber method were determined in 12 healthy male subjects during and after sevoflurane anesthesia. We found that dex-medetomidine augmented baroeflex sensitivity before induction of general anesthesia, but this effect was abolished during and after sevoflurane anesthesia, indicating that sevoflurane-induoed depression of the vagal nerve activity is greater than vagal nerve augmentation by the α2-adrenergic agonist, dex-medetomidine.(4) Correlation between perioperative vagal nerve activity versus cardiac morbidity and mortality Because of inadequate number of patients assigned in this part of the study, no definitive conclusion was drawn in terms of the relationship between perioperative vagal nerve function versus cardiac morbidity and mortality in the intensive care unit patients. Less