Elective tracheostomy during COVID-19 outbreak: to whom, when, how? Early experience from Venice, Italy.

PURPOSE: The need for prolonged invasive mechanical ventilation in COVID-19 patients is placing the otorhinolaryngologist in front of an increasing request for tracheostomy. Nowadays, there is uncertainty regarding the timing of tracheostomy, the prognosis of these patients and the safety of healthcare workers. The aim of this study is to evaluate the efficacy and safety of tracheostomy placement in patients with COVID-19. METHODS: A retrospective cohort study on 23 COVID 19 patients, to analyse the timing of tracheostomy, the risk factors associated with in-hospital death and the infection of the involved health care workers. Early tracheostomy was defined as ≤ 10 days and late ones > 10 days. RESULTS: The mortality rate of COVID-19 patients admitted to ICU that underwent tracheostomy was 18%. The overall mortality of patients admitted to ICU was 53%. The univariate analysis revealed that early tracheostomy, SOFA score > 6, and D-dimer level > 4 were significantly associated with a greater risk of death. At the multivariate analysis SOFA score > 6 and D-dimer level > 4 resulted as significant factors for a higher risk of death. No health care workers associated with tracheostomy are confirmed to be infected by SARS-CoV2. CONCLUSION: We suggest to wait at least 14 days to perform tracheostomy. In patients with SOFA score > 6 and D dimer > 4, tracheostomy should not be performed or should be postponed. Optimized procedures and enhanced personal protective equipment can make the tracheostomy safe and beneficial in COVID-19 patients.

Oil-in-microgel strategy for enzymatic-triggered release of hydrophobic drugs.

Polymer microgels have received considerable attention due to their great potential in the biomedical field as drug delivery systems. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan composed of N-acetyl-d-glucosamine and d-glucuronic acid. This polymer is biodegradable, nontoxic, and can be chemically modified. In this work, a co-flow microfluidic strategy for the preparation of biodegradable HA microgels encapsulating hydrophobic drugs is presented. The approach relies on: (i) generation of a primary oil-in-water (O/W) nanoemulsion by the ultrasonication method, (ii) formation of a double oil-in-water-in-oil emulsion (O/W/O) using microfluidics, and (iii) cross-linking of microgels by photopolymerization of HA precursors modified with methacrylate groups (HA-MA) present in the aqueous phase of the droplets. The procedure is used for the encapsulation and controlled release of progesterone. Degradability and encapsulation/release studies in PBS buffer at 37°C in presence of different concentrations of hyaluronidase are performed. It is demonstrated that enzymatic degradation can be used to trigger the release of progesterone from microgels. This method provides precise control of the release system and can be applied for the encapsulation and controlled release of different types of hydrophobic drugs.