Browsing by Author "Sofi, Umar"

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    A case series of endemic infections associated hemophagocytic lymphohistiocytosis (HLH) mimicking severe sepsis syndrome
    Kollipara, Venkateswara; Hussain, Shahzad; Franco-Palacios; Sofi, Umar (Elsevier, 2019-05-06)
    Hemophagocytic lymphohistiocytosis (HLH) is associated to high mortality and morbidity. A condition often underrecognized, HLH should be in the differential diagnosis of patients presenting with fever, cytopenia, hypertriglyceridemia and high ferritin levels (> 500 μg/L). Acquired or secondary HLH in adults is a heterogenous disease triggered by infectious, autoimmune, or neoplastic conditions. Infection associated HLH (IAHS) have been described in association to immunodeficiency and secondary to infections with endemic pathogens. Extensive investigation with microbiology, serology, urine antigens and biopsies of the bone marrow, lung or lymph nodes are often necessary. We present a series of three adult cases of HLH in patients admitted to the intensive care unit with a presumptive diagnosis of sepsis. Early recognition and treatment of this infection sometimes with concomitant administration of immunosuppressant therapy could impact the high mortality associated to this overlap syndrome.
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    Design and Evaluation of a Novel Method to Noninvasively Estimate Tidal Volumes During Administration of Nasal Cannula Therapy
    Mollica, Hunter Thomas (Virginia Tech, 2024-01-02)
    Administration of nasal cannula therapy tasks providers with periodically monitoring their patients and adjusting settings according to patient needs. Conventionally, providers monitor a patient's oxygen demand using pulse oximetry and a qualitative assessment of the patient's work of breathing. The motivation for this research is to augment the traditional qualitative assessment of work of breathing with a quantitative measurement of a patient's tidal volume, the volume of air inhaled with each breath. This thesis presents a novel approach to measure tidal volume using a nasal cannula with built-in pressure sensors. Pressure waveforms obtained from continuous measurement of the pressure at the tip of the cannula are used to estimate nasal flowrates, and these nasal flowrates are time-integrated to estimate tidal volumes. Computational fluid dynamics (CFD) models were used to simulate fluid flow in a simplified nasal passage undergoing nasal cannula therapy. These simulations used a range of flow conditions characteristic of both low-flow and high-flow nasal cannula treatments. The simulations produced a transformation from cannula tip pressure to instantaneous nasal flowrate, and this transformation was evaluated using a matching empirical experiment. This empirical experiment used a matching physical geometry with a similar range of flow conditions, and the transformation obtained from CFD was able to estimate the actual tidal volumes with 85% accuracy. This study showed that continuous pressure measurement at the tip of a nasal cannula produces enough information to estimate nasal flowrates and tidal volumes. No similar studies were found during the literature review, so an accuracy of 85% is promising for this stage. If this technique could be made more accurate and deployed in an unobtrusive way, the resulting nasal cannula device could be used to continuously, comfortably monitor patients' tidal volumes.