ABSTRACT
In recent years, steerable needles have attracted significant interest in relation to minimally invasive surgery (MIS). Specifically, the flexible, programmable bevel-tip needle (PBN) concept was successfully demonstrated in vivo in an evaluation of the feasibility of convection-enhanced delivery (CED) for chemotherapeutics within the ovine model with a 2.5 mm PBN prototype. However, further size reductions are necessary for other diagnostic and therapeutic procedures and drug delivery operations involving deep-seated tissue structures. Since PBNs have a complex cross-section geometry, standard production methods, such as extrusion, fail, as the outer diameter is reduced further. This paper presents our first attempt to demonstrate a new manufacturing method for PBNs that employs thermal drawing technology. Experimental characterisation tests were performed for the 2.5 mm PBN and the new 1.3 mm thermally drawn (TD) PBN prototype described here. The results show that thermal drawing presents a significant advantage in miniaturising complex needle structures. However, the steering behaviour was affected due to the choice of material in this first attempt, a limitation which will be addressed in future work.
ABSTRACT
Objective: It is increasingly important to identify risk factors for COVID-19-associated mortality to provide access to early treatment. This study aimed to investigate the relationship between COVID-19 severity and laboratory data and demographic characteristics of hospitalized patients and to identify factors predicting mortality in COVID-19. Materials and Methods: The study is a retrospective and single-center study. Data of 1298 COVID-19 patients confirmed by a positive real-time polymerase chain reaction test for COVID-19 and treated at the hospital were retrospectively analyzed. Study patients were divided into three groups based on the clinical severity of disease: the mild-moderate group (n:954) and the severe (n:310) and critical (n:34) groups. Demographic characteristics, underlying diseases, and laboratory findings were compared between groups. Results: Multivariate logistic and ordinal logistic regression analysis revealed that male gender, old age, diabetes mellitus, coronary artery disease, cerebrovascular event, malignancy, chronic obstructive pulmonary disease, chronic renal failure, chronic hepatitis B, and Alzheimer's disease/dementia/Parkinson's disease (among neurological diseases) were independently associated with and significantly increased the development of severe disease and mortality. Conclusion: The COVID-19 pandemic continues to be a significant health problem affecting all of humanity. Determining risk factors for COVID-19 severity and mortality are critical for classifying critical cases at the time of initial diagnosis, establishing appropriately specific treatment protocols, and ensuring access to early treatment.
