COVID-19: Personal Protective Equipment and Infection Control for Retinal Services

 

Alistair Laidlaw, St Thomas’ Hospital, London, UK
Claire Laidlaw, Intensive Care Unit, St Peter’s Hospital, Chertsey, UK

 

COVID-19: Personal Protective Equipment and Infection Control for Retinal Services

The issue of personal protective equipment (PPE) during the COVID-19 pandemic has been a source of great concern to all health and social care workers.  That concern has been increased by inconsistent and changing recommendations as well as both fake and real news. Additionally there is an unfortunately great variation in the availability of PPE between and within countries, regions and cities.  Many healthcare systems are still catching up with the logistics of obtaining and distributing adequate PPE to their healthcare workers.  Advice on appropriate PPE is also changing rapidly.  One good thing is that the rate of change on everything to do with SARS-COVID-2 will slow as systems and procedures become tested in action and modified for purpose.

 

Corona virus, SARS-CoV-2 or COVID-19?

The term ‘Coronavirus’ defines a virus that is transmitted between animals. Severe Acute Respiratory Syndrome (SARS)-CoV-2 is the name of a particular coronavirus that is able to be transmitted to humans. Covid-19 is the disease that results from the virus(1).

 

PPE for Eyecare
There are at least four reasons for Eye Care Clinicians to use appropriate PPE.

1) To protect patients from contracting COVID-19 from the Health Care Worker

At this phase of the pandemic it is reasonable to suggest that healthcare workers are more likely to be asymptomatically infectious than members of the public due to increased exposure.  Additionally, patients attending retinal clinics are at higher than average risk of morbidity or mortality from COVID-19 due to age and/or co-morbidity.  Ideally, the best form of protection would be to avoid these patients entering a healthcare environment. A clinic visit will often involve the use of public transport and inevitably multiple inter personal contacts. Therefore there must be a titration of risk of infection versus benefit of preventing avoidable vision loss. Strategies for limiting attendance to those most in need that have been adopted in different parts of Europe are described elsewhere on the Euretina website.

2) To protect healthcare workers from contracting COVID-19 from patients. 

A vaccination is thought to be more than a year away(2). As a result most individuals can expect to contract the infection at some time over the intervening period.  It is however  vital that the rate of infection in healthcare workers is slowed as much as possible so as to minimise the number of staff on sick leave at any one time.

3) To increase the confidence and morale of both patients and doctors.

Concern about inadequate PPE has been widespread and the subject of much media attention.  Hospitals have at times pre empted increases in the level of PPE being recommended by their government in order to maintain staff and patient confidence.

 

4) Ophthalmology may be high risk 

Eye examinations and treatment involve close prolonged face to face contact between patient and carer, a pan retinal laser may involve 20 or more minutes of such close contact.   It is reasonable to suspect that such situations could increase the chance of cross infection. This ophthalmology specific issue may be under recognised by those providing infection control advice as they are often not familiar with the way we work.

Mechanism of COVID 19 Infection

SARS-COVID 2 infection occurs due to viral transfer of droplets to the respiratory system or conjunctiva(1) .

The virus can be spread via droplets which are generated by coughs or via aerosols created during healthcare interventions such as intubation, suction, drilling and possibly nebulisers. Aerosols may also be created by coughing. Procedures that generate aerosols are referred to as Aerosol Generating Procedures (AGPs). It is not known whether ophthalmic surgery generates aerosols.  A further possible means of transmission is through the faeco-oral route, this is particularly relevant as one of the symptoms of Covid-19 is diarrhoea(3).

Viral particles do not need to be directly transferred by a cough or aerosol from one individual to another.  SARS-CoV-2 can persist for many days on inanimate surfaces (worktops, slit lamps, lenses, toilets).  It can conceivably be re-distributed into the air if those surfaces are physically disturbed or transferred from an infected individual or contaminated surface on fingers or gloves. An alarming statistic is that normal human behaviour involves touching one’s face on average 23 times an hour and each touch has the potential to transfer infection(4). If nothing else, the importance of hand hygiene, whether with bare hands or gloves, and not touching your face cannot be over emphasised when discussing infection prevention.

Correct putting on and taking off of PPE is vital, incorrect technique is a key cause of health care worker infection. Proper procedure for removing gloves, aprons and masks must be followed and hand washing or hand sanitising must be carried out between each stage(5).

 

Treat All Patients As If Infected

Many services are now advising staff that all patients should be regarded as being infected with SARS-CoV-2, whether symptomatic or not, in order to reduce the risk of cross infection. This is because there can be viral shedding for several days before patients begin displaying signs of COVID-19.  Even in those infected the viral PCR tests from throat or nose swabs may only be 50-60% sensitive and so cannot be relied upon(6).

Are Ophthalmologists More at Risk?

There is a widely held belief that the intensity of initial viral inoculation may increase the severity of subsequent clinical infection. This is undoubtedly fuelled by the news of the death of Ophthalmologists and ENT Surgeons from COVID-19.  We spend much of our time in close face to face contact so it is natural to be concerned that Ophthalmologists would be exposed to a higher volume of droplets. There is conflicting evidence with regards to this but a recent independent review has suggested that whilst the evidence to support this is weak a relationship cannot be ruled out. Additionally our proximity to patients, and therefore greater exposure to SARS-CoV-2 carrying droplets, cannot be denied even if a link to clinical severity has not been established.   It is important that staff concern is acknowledged in order to maintain morale in the face of unclear evidence. The provision of appropriate PPE is  one way to recognise such concern(7).

 

PPE: What and When

An important conclusion in a recent UK independent academic review is that a standard water repellent surgical mask, gloves and apron are adequate unless an AGP is being performed, in which case higher level PPE including an FFP3 respirator is required(2,9).

It is vital to remember that PPE is only one part of safe and effective infection control including minimising patient contact, maintaining a gap of at least a meter when possible and routine disinfection of equipment and surfaces(9).

PPE and Infection Control for Routine Ophthalmology Encounters and Eye Injections

  1. A) All Eye Care Staff Coming Within 1m of a Patient
  • Gloves, changed between patient examinations. Wash or antibacterial gel hands with every change of glove.
  • Surgical masks last up to 4 hours(8). They should be left on if possible and if removed, changed. Only ever touch the strings not the mask. If you accidentally touch the mask at a time other than when taking it off then it must be removed and replaced.
  • Plastic apron. Do not touch the front of the apron once it is on.  Change the apron after any consultation in which it may have become contaminated by gloves or coughing.
  • Consider surgical scrubs rather than standard clothing, or daily clean top and bottom clothing.

 

Instructions and a Video on putting on and taking off personal protective equipment are given here:

 

  1. B) Specific additional measures for eye examinations and injections:
  • Avoid using the slit lamp if at all possible. If you have to use the slit lamp fit a breath guard as illustrated below.
  • Avoid contact with eyelids.
  • Clean non contact lenses (ie 78D) between patients. Disinfect thoroughly according to local protocols with virocidal wipes or spray.
  • Avoid contact tonometry or contact lenses unless absolutely vital. Dispose or disinfect thoroughly according to local protocols with virocidal agents.
  • Eye protection (visor or goggles) for injections. Standard glasses are not considered adequate.
  • Avoid examining patients with conjunctivitis

The question of eye protection is important. Visors or goggles are generally recommended if there is a risk of  splashes or AGPs are being carried out(9).  AGPs may be relatively unlikely in outpatient  Ophthalmology and visors and goggles do not work well with the optics of slit lamps or indirect ophthalmoscopes. A pragmatic compromise is providing large clear plastic breath guards for both instruments to reduce any droplet spread. These are now available commercially and instructions for making temporary versions are easily found online.

 

Coronaviruses are generally susceptible to standard clinical disinfectants such as dilute bleach, alcohol gel and medical wipes.  Many medical disinfectant wipes need a 60 seconds contact time: wipe and leave to dry appears to be the message(10,11).   Disinfection of clinical equipment should rigorously follow local guidelines.

 

The use of surgical scrubs may be advisable but the increased turnover of scrubs must be feasible within the unit.  Most staff will change their shirt every day, but not their trousers, which could be a source of spread.  It is sensible to travel to work in one outfit and change into another when at work, be it scrubs or personal clothing.  Potentially infected clothing should be placed in an appropriate laundry bin or a sealed plastic bag and washed at 60 degrees Celcius or above(9,12).

 

PPE for Ophthalmic Surgery

 

Ophthalmic surgery and laser in most countries is being limited to emergencies only. Such procedures involve the surgeons head being within 30 to 50 cm of the patients head for long periods of time and patients will frequently cough.  It is unknown whether Ophthalmic surgery creates an aerosol, however mist can sometimes be seen with Phako procedures.  Surgical drapes cannot be relied upon to create a sustained barrier between the patients breath, the operating area and the surgeons airway as they rarely stick reliably for a whole procedure.  It seems reasonable to suggest the use of PPE which is relevant to AGPs for the few eye operations and PRP laser procedures that are needed(13).

 

References

1) ECDC. Q & A on COVID-19 [Internet]. European Centre for Disease Prevention and Control. 2020 [cited 2020 Mar 31]. Available from: Click here to view

2) Nebehey S, MAcfie N. Vaccine for new coronavirus “COVID-19” could be ready in 18 months: WHO – Reuters [Internet]. Reuters. 2020 [cited 2020 Mar 31]. Available from: Click here to view

3) Greenhalgh T, Chan XH, Khunti K, Durand-Moreau Q, Straube S, Devane D, et al. What is the efficacy of standard face masks compared to respirator masks in preventing COVID-type respiratory illnesses in primary care staff? – CEBM [Internet]. Oxford; 2020 [cited 2020 Mar 31]. Available from: Click here to view

4) Kampf G, Todt D, Pfaender S, Steinmann E. Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents. J Hosp Infect. 2020 Mar;104(3):246–51.

5) Reddy SC, Valderrama AL, Kuhar DT. Improving the Use of Personal Protective Equipment: Applying Lessons Learned. Clin Infect Dis [Internet]. 2019 Sep 13 [cited 2020 Mar 31];69(Supplement_3):S165–70. Available from: Click here to view

6) Wang W, Xu Y, Gao R, Lu R, Han K, Wu G, et al. Detection of SARS-CoV-2 in Different Types of Clinical Specimens. JAMA. 2020 Mar 11;

7) Brassey J, Heneghan C, Jefferson T. SARS-CoV-2 viral load and the severity of COVID-19 [Internet]. Nuffield Department of Primary Health Care Sciences. 2020 [cited 2020 Mar 31]. Available from: Click here to view

8) Barbosa MH, Graziano KU. Influence of wearing time on efficacy of disposable surgical masks as microbial barrier. Brazilian J Microbiol [Internet]. 2006 Sep [cited 2020 Mar 31];37(3):216–7. Available from: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822006000300003&lng=en&nrm=iso&tlng=en

9) Department of Health and Social Care, Public Health Agency Northern Ireland, Public Health Wales, Health Protection Scotland, Public Health England. COVID-19 Guidance for infection prevention and control in healthcare settings Adapted from Pandemic Influenza: Guidance for Infection prevention and control in healthcare settings 2020 [Internet]. 2020 [cited 2020 Mar 31]. Available from: Click here to view

10) Ecdc. Infection prevention and control for COVID-19 in healthcare settings [Internet]. 2020 [cited 2020 Mar 31]. Available from: Click here to view

11) Clinell. GAMA Healthcare Latest | Clinell efficacy against coronavirus (COVID-19) [Internet]. game healthcare. 2020 [cited 2020 Mar 31]. Available from: Click here to view

12) Battles, D., & Vesley, D. (1981). Wash Water Temperature and Sanitation In the Hospital Laundry. Journal of Environmental Health,43(5), 244-250. Retrieved March 31, 2020, from www.jstor.org/stable/44537695

13) Public Health England. COVID-19: personal protective equipment use for aerosol generating procedures – GOV.UK [Internet]. GOV.UK. 2020 [cited 2020 Mar 31]. Available from: https://www.gov.uk/government/publications/covid-19-personal-protective-equipment-use-for-aerosol-generating-procedures

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