Anaesthesia
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The global COVID-19 pandemic has led to a worldwide shortage of ventilators. This shortage has initiated discussions on how to support multiple patients with a single ventilator (ventilator splitting). Ventilator splitting is incompletely tested, experimental and the effects have not been fully characterised. ⋯ The restriction apparatus successfully modified the inspiratory pressure, minute ventilation and volume delivered to the high compliance test lungs in both pressure control (27.3-17.8 cmH2 O, 15.2-8.0 l.min-1 and 980-499 ml, respectively) and volume control (21.0-16.7 cmH2 O, 10.7-7.9 l.min-1 and 659-498 ml, respectively) ventilation modes. Ventilator splitting is not condoned by the authors. However, these experiments demonstrate the capacity to simultaneously ventilate two test lungs of different compliances, and using only standard hospital equipment, modify the delivered pressure, flow and volume in each test lung.
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The first person-to-person transmission of the 2019 novel coronavirus in Italy on 21 February 2020 led to an infection chain that represents one of the largest known COVID-19 outbreaks outside Asia. In northern Italy in particular, we rapidly experienced a critical care crisis due to a shortage of intensive care beds, as we expected according to data reported in China. Based on our experience of managing this surge, we produced this review to support other healthcare services in preparedness and training of hospitals during the current coronavirus outbreak. ⋯ Dedicated protocols were applied where full isolation of spaces, staff and patients was implemented. Opening the unit and the whole hospital emergency process required the multidisciplinary, multi-level involvement of healthcare providers and hospital managers all working towards a common goal: patient care and hospital safety. Hospitals should be prepared to face severe disruptions to their routine and it is very likely that protocols and procedures might require re-discussion and updating on a daily basis.
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Chronic pain causes significant suffering, limitation of daily activities and reduced quality of life. Infection from COVID-19 is responsible for an ongoing pandemic that causes severe acute respiratory syndrome, leading to systemic complications and death. Led by the World Health Organization, healthcare systems across the world are engaged in limiting the spread of infection. ⋯ There are no guidelines to inform physicians and healthcare providers engaged in caring for patients with pain during this period of crisis. We assembled an expert panel of pain physicians, psychologists and researchers from North America and Europe to formulate recommendations to guide practice. As the COVID-19 situation continues to evolve rapidly, these recommendations are based on the best available evidence and expert opinion at this present time and may need adapting to local workplace policies.
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Why do we need another PPE review?
This review contextualises the PPE issues with their (relatively low quality) evidence base, focusing particularly on anaesthesia given that this is a high-risk occupational group. Coming from both a UK expert and journal, the recommendations should be carefully considered in terms of the UK's severe COVID outbreak and PPE supply issues.
Important takeaways?
- The significance of airborne transmission, in particular the infectivity of airborne viral particles beyond 1 meter, is uncertain.
- PPE should be seen as an important and essential part of a larger safety system.
- Intubation is a high-risk procedure for aerosol generation. A ventilated negative pressure room and airborne-precaution PPE is recommended. Ventilation (frequency of air-exchange) is likely more important than negative pressure.1 Chinese evidence suggests COVID transmission at intubation is low with appropriate PPE, although there is wide variability in extremes of PPE used along with post-exposure disinfection (eg. showering).
- High-flow nasal oxygen and supraglottic airway (eg. LMA) placement may also be aerosol generating.
- Most risk of transmission from sneezing and coughing is probably droplet and contact, rather than airborne, although the science behind these questions are complex and uncertain. Evidence attempting to answer these questions is often from non-clinical settings.
- Fluid-resistant surgical masks when worn by staff may reduce transmission by at least 80%. Superiority of respirator masks (eg. P2,P3,N95) is not yet reliably supported by evidence.
- Cook highlights two main PPE problems: 1. PPE supply; 2. Inappropriate use of PPE (using higher level than required).
- PPE should be simple to remove (doff) after use, to reduce contamination risk. Cook notes that Canada's SARS experience highlighted increased risk of self contamination with more complex PPE.
On specific levels of PPE
- Contact precautions (gloves & gown) are recommended when in vicinity of COVID positive patient but not within 2 meters.
- Droplet precautions (+ mask & eye protecting) are recommended within 2 meters of patients.
- Airborne precautions (+ FFP3 respirator mask) are only recommended for aerosol generating procedures (AGP). However classification of procedures as AGP or not is only loosely evidence based.
"Public Health England recommends airborne precautions are used in ‘hot spots’ where aerosol generating procedure are regularly performed, if any suspected COVID-19 patients are present – these include intensive care unit, operating theatre, emergency department resuscitation bays and labour wards where mothers are in stage 2 or 3 of labour"
(Interesting that two recent meta-analyses found no evidence of benefit of N95 masks vs surgical masks for healthcare workers: Bartoszko 2020 & Long 2020.)
Hang on...
The elephant in the room is that the lack of PPE supply appears to be the main driver of the rapidly-changing PPE recommendations.
PPE choices need to be made in consideration of the spectrum of risk, hazard and cost, acknowledging different risk profiles depending on location, procedure and individual clinicians.
summary
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It's worth highlighting that negative pressure confers no protection on those in the room, it's purpose is to prevent escape of contagion to areas outside the room. ↩