Sherif R. Gobran

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The predictions of a single-path trumpet-bell numerical model of steady-state CO2 and infused He and sulfur hexafluoride (SF6) washout were compared with experimental measurements on healthy human volunteers. The mathematical model used was a numerical solution of the classic airway convention-diffusion equation with the addition of a distributed source(More)
BACKGROUND Off-pump coronary artery bypass (OPCAB) may be associated with improved outcomes when compared with on-pump coronary artery bypass. This study evaluates the use of a system for access and stabilization (SAS) with a coronary stabilizer as well as a clinical effectiveness quality initiative (CEQI) process regarding outcomes. This included the(More)
A numerical solution of the convection-diffusion equation with an alveolar source term in a single-path model (SPM) of the lung airways simulates steady state CO2 washout. The SPM is used to examine the effects of independent changes in physiologic and acinar structure parameters on the slope and height of Phase III of the single-breath CO2 washout curve.(More)
We modified, and developed software for, a computer-controlled quadrupole mass spectrometer to measure complete breath-by-breath expirograms of helium (He) and sulfur hexafluoride (SF6) exhaled during the infusion of saline saturated with the inert gases. He and SF6 have similar blood solubilities but very different gas phase diffusivities allowing(More)
We studied the influence of acinar morphometry on the shape of simulated expirograms computed from a single path convection-diffusion model that includes a source term for gas evolution from the blood (Scherer et al., J. Appl. Physiol. 64: 1022-1029, 1988). Acinar structure was obtained from published data of 3 different lung morphometries. The simulations(More)
We investigated the effect of increasing doses of intravenously infused glass microspheres (mean diameter 125 microns) on gas exchange in anesthetized, heparinized, mechanically ventilated goats (VT = 16-18 ml/kg). Breath-by-breath CO2 expirograms were collected using a computerized system (Study A) during the infusion of a total of 15 g of microspheres. We(More)
A model is presented that relates the change in baroreceptor firing rate to a step change in blood pressure. This relationship is nonlinear since the alteration in rate of firing depends on the current rate of firing. It is shown that this simple relationship embodies all currently established baroreceptor response modes. The model needs refinement to allow(More)
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