Establishing local manufacture of PPE for healthcare workers in the time of a global pandemic

A face shield is a secondary personal protective equipment (PPE) for healthcare workers (HCW). Worn with the appropriate face masks/respirators, it provides short term barrier protection against potentially infectious droplet particles. Coronavirus disease 2019 (COVID-19) caused a spike in demand for PPE, leading to a shortage and risking the safety of HCW. Transport restrictions further challenged the existing PPE supply chain which has been reliant on overseas-based manufacturers. Despite the urgency in demand, PPE must be properly tested for functionality and quality. We describe the establishment of local face shields manufacture in Western Australia to ensure adequate PPE for HCW. Ten thousand face shields for general use (standard) and for ear, nose and throat (ENT) specialist use were produced. Materials and design considerations are described, and the face shields were vigorously tested to the relevant Standards to ensure their effectiveness as a protective barrier, including splash and impact resistance. Comparative testing with traditional and other novel face shields was also undertaken. Therapeutic Goods Administration (TGA) licence was obtained to manufacture and supply the face shields as a Class I medical device. The swiftness of process is a credit to collaboration from industry, academia and healthcare.

Low endothelial shear stress, microcalcification activity and high-risk plaque features: merging computational flow modelling, OCT and 18F-NaF PET/CT

Background

Endothelial shear stress (ESS) has a critical role in endothelial function. Abnormal shear stress leads to endothelial dysfunction, which contributes to arterial plaque initiation and development. Four dimensional magnetic resonance can determine shear stress in the larger arteries but cannot resolve the detail needed to calculate shear stress in the coronary arteries and thus methods such as computational fluid dynamics (CFD) are required. Additionally, a key feature of biologically active plaques is microcalcification activity, and this can be detected using 18F-sodium fluoride (18F-NaF) positron emission tomography (PET). Furthermore, using high resolution optical coherence tomography (OCT), the high-risk features plaques can be visualized and quantified. We aimed to merge these three techniques to investigate if low ESS is associated with high-risk plaque features and active microcalcifications in acute coronary syndrome.

Methods

We began by merging OCT images with CTCA images to obtain detailed 3D reconstructions of the target vessel. We then simulated blood flow and calculated the ESS, from which we extracted the area of low ESS (<0.4 Pa). We quantified plaque features using OCT and measured the maximum 18F-NaF uptake, and compared data at both the coronary segment and whole artery level (Figure 1).

Results

We investigated 20 arteries from 18 patients which we obtained 38 coronary segments according to the SCCT guidelines. We found that areas of low ESS were were significantly and positively associated with high-risk plaque features: macrophage infiltration (segment, rs=0.33, p=0.043; artery, rs=0.46, p=0.041) and presence of cholesterol crystals (segment, rs=0.45, p=0.005; artery, rs=0.58, p=0.007). Vessel segments with thin-capped fibroatheroma had greater area of low ESS (20 vs 4%). The uptake of 18F-NaF was positively associated with the area of low ESS (segment, rs=0.52, p=0.001; artery, rs=0.64, p=0.002). We found that there were typically more plaque features found in regions of low ESS (Table 1).

Conclusion

Here we provide the first data associating low ESS with both high-risk plaque features and active microcalcifications in patients with acute coronary syndrome. Although our sample size is small, these data are encouraging and could lead to better understanding of how best to deem a plaque “high risk”.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Royal Perth Hospital Medical Research Foundation Figure 1Table 1

Thrombosis risk in the trauma patient. Prevention and treatment

Hypercoagulability is frequently seen in the trauma patients. Debate continues over the best method of prophylaxis, diagnosis, and treatment for the trauma patient. From experience with orthopedic and general surgery patients, much has been learned about prophylaxis and diagnosis, and as treatment protocols have been taken from internal medicine literature. Universal guidelines relating specifically to the trauma patient have not, however, been established. Overall, most of the literature suggests using LMWH for the prophylaxis of trauma patients. When LMWH is contraindicated, SCD should be used, with AVFP as a second choice. Surveillance screening for DVT remains controversial, but surveillance before transfer to extended care facilities has proven beneficial. Finally, when DVT is diagnosed, treatment should be initiated as soon as possible and should be continued until the DVT has resolved. Long-term anticoagulation therapy or use of caval filters may be necessary to prevent the morbidity of PE or thrombophlebitic syndrome.