Adapting re-usable elastomeric respirators to utilise anaesthesia circuit filters using a 3D-printed adaptor - a potential alternative to address N95 shortages during the COVID-19 pandemic.

The COVID-19 pandemic has increased the demand for disposable N95 respirators. Re-usable elastomeric respirators may provide a suitable alternative. Proprietary elastomeric respirator filters may become depleted as demand increases. An alternative may be the virus/bacterial filters used in anaesthesia circuits, if they can be adequately fitted onto the elastomeric respirators. In addition, many re-usable elastomeric respirators do not filter exhaled breaths. If used for sterile procedures, this would also require modification. We designed a 3D-printed adaptor that permits elastomeric respirators to interface with anaesthesia circuit filters and created a simple modification to divert exhaled breaths through the filter. We conducted a feasibility study evaluating the performance of our modified elastomeric respirators. A convenience sample of eight volunteers was recruited. Quantitative fit testing, respiratory rate and end-tidal carbon dioxide were recorded during fit testing exercises and after 1 h of wear. All eight volunteers obtained excellent quantitative fit testing throughout the trial. The mean (SD) end-tidal carbon dioxide was 4.5 (0.5) kPa and 4.6 (0.4) kPa at baseline and after 1 h of wear (p = 0.148). The mean (SD) respiratory rate was 17 (4) breaths.min-1 and 17 (3) breaths.min-1 at baseline and after 1 h of wear (p = 0.435). Four out of eight subjects self-reported discomfort; two reported facial pressure, one reported exhalation resistance and one reported transient dizziness on exertion. Re-usable elastomeric respirators to utilise anaesthesia circuit filters through a 3D-printed adaptor may be a potential alternative to disposable N95 respirators during the COVID-19 pandemic.

A case of human brucellosis in Hong Kong.

Brucellosis is an infectious disease of humans and animals caused by Brucella species. We report on a 34-year-old housewife who presented with recurrent headache, fever, and malaise. Blood cultures yielded slow-growing gram-negative coccobacilli that were later identified as Brucella melitensis. The patient recalled handling goat placenta in China. She was prescribed a 6-week course of doxycycline and rifampicin. Laboratory staff who had been exposed to the isolate remained asymptomatic. The epidemiology, diagnosis, and treatment of brucellosis are discussed.

Pertussis--a re-emerging infection?

Seven cases of pertussis in patients aged between 1 and 6 months detected over 3 months were reported. Paroxysmal cough (six cases), post-tussive vomiting (three cases) and poor feeding (three cases) were the most common presenting symptoms. Bordetella pertussis was isolated from six patients. The total leucocyte counts were mildly increased (10.8-15.6x10(9)/L). The lymphocyte counts were markly raised (59-73%) and appear to be useful indicators of pertussis. It appears that herd immunity does not offer adequate protection to the vulnerable group even in well-vaccinated populations. High vaccination coverage should be maintained, and vaccination should be given as early an age as possible. Aggressive efforts to identify cases and contacts are essential. Health care workers should have a high index of suspicion for pertussis, in particular for those with paroxysmal cough and high lymphocyte counts so as to give timely diagnosis and treatment.

Infection control for SARS in a tertiary neonatal centre.

The Severe Acute Respiratory Syndrome (SARS) is a newly discovered infectious disease caused by a novel coronavirus, which can readily spread in the healthcare setting. A recent community outbreak in Hong Kong infected a significant number of pregnant women who subsequently required emergency caesarean section for deteriorating maternal condition and respiratory failure. As no neonatal clinician has any experience in looking after these high risk infants, stringent infection control measures for prevention of cross infection between patients and staff are important to safeguard the wellbeing of the work force and to avoid nosocomial spread of SARS within the neonatal unit. This article describes the infection control and patient triage policy of the neonatal unit at the Prince of Wales Hospital, Hong Kong. We hope this information is useful in helping other units to formulate their own infection control plans according to their own unit configuration and clinical needs.