Browsing by Author "Zuege, Danny J."

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    Antibiotic Utilization Patterns in Patients with Ventilator-Associated Pneumonia: A Canadian Context
    (2016-07-20) Chin, Tracy; Kushner, Barry; Dersch-Mills, Deonne; Zuege, Danny J.
    This retrospective cohort study describes the patterns of antibiotic use for the treatment of ventilator-associated pneumonia (VAP) in the Calgary Zone of Alberta Health Services. Timing, appropriateness, and duration of antibiotics were evaluated in two hundred consecutive cases of VAP derived from 4 adult intensive care units (ICU). Antibiotic therapy was initiated in less than 24 hours from VAP diagnosis in 83% of cases. Although most patients (89%) received empiric therapy that demonstrated in vitro sensitivity to the identified pathogens, only 24% of cases were congruent with the 2008 Association of Medical Microbiology and Infectious Disease (AMMI) guidelines. Both ICU () and hospital () mortality were significantly lower and there was a trend for shorter ICU length of stay () in patients who received appropriate versus inappropriate initial antibiotics. There were no outcome differences related to compliance with AMMI guidelines. This exploratory study provides insight into the use of antimicrobials for the treatment of VAP in a large Canadian health region. The discordance between the assessments of appropriateness of empiric therapy based on recovered pathogens versus AMMI guidelines is notable, emphasizing the importance of using as much as possible local microbiologic and antimicrobial resistance data.
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    Development and Evaluation of Risk Models to Predict Readmission or Death Following Discharge from an Adult General Systems Intensive Care Unit
    (2018-07-06) Boyd, Jamie; Stelfox, Henry Thomas; James, Matthew T.; Zuege, Danny J.
    Transitions of care from intensive care unit (ICU) to ward are high-risk periods of healthcare delivery associated with ICU readmission and post-ICU mortality. Evidence-based processes for transitions are crucial for improving outcomes. Validated prediction models that include consistently associated risk factors for ICU readmission or post-ICU mortality may help to improve these practices. This mixed-methods thesis was comprised of three distinct phases: 1) systematic review and meta-analysis; 2) development of prediction models for ICU Readmission and Post-ICU Mortality using two approaches (literature-derived coefficients, data-derived coefficients [Derivation Cohort]), 3) validation of the models in an external Validation Cohort. The models for ICU Readmission showed limited discriminative ability whereas the Post-ICU Mortality models were stronger. Developing prediction models using pooled measures of association is a feasible approach, producing similar results to more the traditional data-derived method. Additional investigation to further validate the findings is required.
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    Neural Respiratory Drive and Respiratory Muscle Function During CO2 Stimulation
    (2022-06-15) Tagliabue, Giovanni; Easton, Paul Alexander; Zuege, Danny J.; Leguillette, Renaud; Day, Trevor
    Background. The use of EMG of the respiratory muscles as a surrogate of the central neural respiratory drive is gaining clinical popularity. Currently, the clinical EMG recording of the crural diaphragm by an esophageal electrodes probe (EAdi) is promoted as a “gold standard”. Additionally, other inspiratory muscles have been investigated as a less invasive alternative, especially the surface EMG of parasternal intercostal. Now there is major clinical interest focusing on the EMG of abdominal muscle as indicator of diaphragm weakness. However, all these clinical applications rely on physiological and technical assumptions that are not fully elucidated. Theme. The focus of this thesis is to address the following questions: 1) do crural and costal diaphragm share an identical neural-mechanical profile during inspiration? 2) does crural and costal diaphragm activity extend into, and contribute identically, during expiration? 3) does the parasternal intercostal share a similar neural activation with the diaphragm during inspiration? 4) is the current clinical technique, recording the surface EMG of parasternal intercostal? 5) is the expiratory phase a passive physiologic process, so that the activation of the abdominal muscles is a pathological indicator? Projects. This thesis is organized as a series of related projects, corresponding to individual chapters addressing each physiological question. The successful execution of this thesis work relied upon a model of a large, normal, intact mammals group, with intact airways, awake without anesthetic, at rest during spontaneous breathing. And, we did further measurements during progressive chemical stimulation by hypercapnia. Summary. We found that the crural and costal diaphragm each exhibit a distinct neural mechanical profile during inspiration, and the differentiation in their operational role extends into the early phase of expiration. Therefore, the clinical assumption that the crural diaphragm is representative of the whole diaphragm is not supported. Our results support the use of parasternal intercostal as a surrogate of neural respiratory drive. However, we confirmed that the current technique based on surface EMG is not reliable due to intrinsic physiologic limitations. Finally, our findings reinforce the concept that expiration is not a passive process but actively contributes to inspiration.
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