A recently proposed analytical hemodynamie modell[s.Fantini,Neurolmage 85,202-221(2014)]is able to predict the changes of oxy,deoxy,and total hemoglobin concentrations(model outputs)given arbitrary changes in blood fl...A recently proposed analytical hemodynamie modell[s.Fantini,Neurolmage 85,202-221(2014)]is able to predict the changes of oxy,deoxy,and total hemoglobin concentrations(model outputs)given arbitrary changes in blood flow,blood volume,and rate of oygen consumption(model inputs).One asumption of this model is that the capillary compartment is characterized by a single blood transit time.In this work,we have extended the original model by considering a distribution of capillary transit times and we have compared the outputs of both models(original and extended)for the case of sinusoidal input signals at different frequencies,which realizes the new technique of coherent hemodynamics spectroscopy(CHS).For the calculations with the original model,we have used the mean value of the distribution of capillary transit times con-sidered in the extended model.We have found that,for distributions of capillary transit times having mean values around 1 s and a standard deviation less than about 45%of the mean value,the original and extended models yield the same CHS spectra(i.e.,model outputs versus fre-quency of ocillation)within typical experimental errors.For wider capillary transit time dis-tributions,the two models yield different CHS spectra.By assuming that Poiseuille's law is valid in the capillary compartment,we have related the distribution of capillary transit times to the distributions of capillary lengths and capillary speed of blood flow to calculate the average capillary and venous saturations.We have found that,for standard deviations of the capillanry transit time distrilbution that are less than about 80%of the mean value,the average capillary saturation is always larger than the venous saturation.By contrast,the average capillary satu-ration may be less than the venous saturation for wider distributions of the capillary transit times.展开更多
Capillary leak syndrome(CLS)is a rare clinical syndrome associated with significant morbidity and mortality.Intensive care and supportive therapy constitute the mainstay of the treatment,along with judicious use of cr...Capillary leak syndrome(CLS)is a rare clinical syndrome associated with significant morbidity and mortality.Intensive care and supportive therapy constitute the mainstay of the treatment,along with judicious use of crystalloids and colloids such as dextran and starch during the leak phase.The advantages of proning,steroids,and intravenous immunoglobins are worth contemplating in patients with such a presentation.Extracorporeal membrane oxygenation appears to be an excellent strategy to surmount the impediments of the leak and post leak phase of CLS,especially in patients with severe or refractory hypoxemia.展开更多
基金supported by the National Institutes of Health (Grant No.R01-CA154774)by the National Science Foundation (Award No.IIS1065154).
文摘A recently proposed analytical hemodynamie modell[s.Fantini,Neurolmage 85,202-221(2014)]is able to predict the changes of oxy,deoxy,and total hemoglobin concentrations(model outputs)given arbitrary changes in blood flow,blood volume,and rate of oygen consumption(model inputs).One asumption of this model is that the capillary compartment is characterized by a single blood transit time.In this work,we have extended the original model by considering a distribution of capillary transit times and we have compared the outputs of both models(original and extended)for the case of sinusoidal input signals at different frequencies,which realizes the new technique of coherent hemodynamics spectroscopy(CHS).For the calculations with the original model,we have used the mean value of the distribution of capillary transit times con-sidered in the extended model.We have found that,for distributions of capillary transit times having mean values around 1 s and a standard deviation less than about 45%of the mean value,the original and extended models yield the same CHS spectra(i.e.,model outputs versus fre-quency of ocillation)within typical experimental errors.For wider capillary transit time dis-tributions,the two models yield different CHS spectra.By assuming that Poiseuille's law is valid in the capillary compartment,we have related the distribution of capillary transit times to the distributions of capillary lengths and capillary speed of blood flow to calculate the average capillary and venous saturations.We have found that,for standard deviations of the capillanry transit time distrilbution that are less than about 80%of the mean value,the average capillary saturation is always larger than the venous saturation.By contrast,the average capillary satu-ration may be less than the venous saturation for wider distributions of the capillary transit times.
文摘Capillary leak syndrome(CLS)is a rare clinical syndrome associated with significant morbidity and mortality.Intensive care and supportive therapy constitute the mainstay of the treatment,along with judicious use of crystalloids and colloids such as dextran and starch during the leak phase.The advantages of proning,steroids,and intravenous immunoglobins are worth contemplating in patients with such a presentation.Extracorporeal membrane oxygenation appears to be an excellent strategy to surmount the impediments of the leak and post leak phase of CLS,especially in patients with severe or refractory hypoxemia.
