VIEWPOINT

A model respiratory personal protective programme for the healthcare industry Chris Walls, Geraint Emrys, Siobhan Gavaghan, Des Gorman, David McBride, Dave McLean

ABSTRACT In the absence of advice from the workplace regulator, a model respiratory protection programme for healthcare workers is presented based in healthcare and wider industry experience. Hospital and other healthcare institutions can use this as a basis for their programmes in preparation for the next infective disease outbreak.

n the current COVID pandemic, personal and controlling . Hazards can be protective equipment (PPE) has been a assessed against standards, for chemicals in presented as a solution for the respirato- air there are workplace exposure standards I 5 ry protection of healthcare workers (HCWs), (WES’s) which should not be exceeded. In imperfectly applied because of logistics and healthcare there are a number of chemical supply problems. The real problem, howev- exposures including waste anaesthetic gases, er, lies elsewhere, in that PPE is seldom de- cytotoxic agents and electrosurgical smoke, ployed correctly: its is only one component but the principal resides in infec- of a health protection system. tious agents, for which exposure standards Although WorkSafe New Zealand1 recom- have not been set, but the same control prin- mends a respiratory protection programme, ciples apply. no guidance is given on how to design one, With regard to the latter, the Health despite the existence of an Australian/New and Safety (General Risk and Workplace Zealand Standard2 and the development of Management) Regulations 2016 6 draw on specifi c guidelines in Australia.3 We trust a long established and empirically proven that our experiences in applying the basic occupational health and safety principle, principles of respiratory protection in the ‘hierarchy of control’.7 The hazard industrial settings will prove to have direct should be either eliminated, impracticable applicability to the health sector. In the for biological exposures unless a vaccine is absence of advice from the workplace regu- available, or isolated in a suitable facility lator, we offer these thoughts to promote with specially trained staff, for example a better understanding of the problem so that nosocomial or intensive care unit. If the HCWs achieve adequate protection. hazard remains then it must be minimised The statutory duties imposed on a person by, in order of importance, engineering in control of a business unit (PCBU) by the controls, safe work practices, and, failing all Health and Safety at Work Act 2015 4 (The else, by the use of PPE, which attempts to Act) lies at the heart of the problem: they control any residual risk. have a primary duty of care and must, so The implications are that a safe work- far as is reasonably practicable, provide place, particularly in complex industries and maintain a work environment that is such as healthcare, requires a health and without health and safety risks. Under safety system underpinning the optimal the provisions of the Act, work risks are combination of an appropriately engineered to be managed by identifying, assessing work environment, safe work practices, the

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use of the most effective PPE, monitoring of by droplet and contact routes. Although the work environment and fi nally, adequate there have been no reports of the latter the information and training. The effi cacy of WHO advice is that “fomite transmission is such programmes should be subject to considered a likely mode of transmission periodic audit. for SARS-Cov-2 given consistent fi ndings For HCWs in some circumstances, PPE about environmental contamination in the may be the only effective hazard control vicinity of infected cases and the fact that mechanism, blood or body fl uid expo- other coronaviruses and respiratory viruses sures being an example. With airborne can transmit this way”. The WHO therefore hazards, engineering solutions must not recommends droplet and contact precau- be overlooked, and remain a cornerstone tions when caring for COVID 19 patients. of the healthcare model. Airborne precautions are recommended An example is the best practice require- during aerosol generating procedures, the ments for operating theatre ventilation are use of N95, fi ltering face piece (FFP)2 or effective at managing the risks from waste FFP3 respirators. anaesthetic gas and electrosurgical smoke. The situation with respiratory protective Ventilation can help to manage biological equipment, RPE, is therefore complex hazards. As an example, the risk of occupa- and requires thorough analysis and the tional conversion of tuberculosis status is development of an ‘in-depth’ protection much reduced in clinical areas with appro- programme. Experience with viral haem- priate ventilation.8 orrhagic fever has shown that ‘standard precautions’, the suite of infection If ventilation fails to control the hazard, prevention and control measures, must be then respiratory protective equipment (RPE) allied to the use of PPE, and the combination is the fi nal option, simply because it is least treated as an ensemble: training, for example likely to prove effective, largely because of in donning and doffi ng, is crucial to success.13 human behaviour or environmental factors, a seminal example being the use of PPE in Having decided that RPE is necessary to the hot and humid conditions of the freezing reduce residual risk, appropriate equipment works, which has actually been shown to must be selected. Up to now, N95 respirators increase the risk of leptospirosis in meat and surgical masks have been the most workers.9 The associated costs of human widely discussed options. leptospirosis due to time absent from work N95 masks are available in different sizes and treatment have also been calculated to and contours, and designed to fi t closely be $4.42 US million per annum (95% prob- around the nose and mouth. They are elec- ability interval: 2.04–8.62) million).10 The trostatically charged to fi lter out particulate possible costs of SARS-CoV-2 is likely to be matter, but not virus droplets. Half face much greater. respirators with fi lters are also available and Modelling of SARS-CoV-2 virus trans- comply with a standard, having an assigned mission is complex, but a key fi nding of a protective factor (APF) of 10, meaning that study by Jones11 was that droplet, inhalation no more than one-tenth of the contaminants and contact routes contribute respectively to which the worker is exposed leak or pass 14 35%, 57% and 8.2% of the probabability through into the mask. of infection, on average, without the use Surgical masks are loose fi tting, have of PPE. While the virus emission rates no APF and are not considered to be RPE: remain uncertain, Jones concludes “that they cannot be fi t tested.15 Both the N95 inhalation exposure is likely to contribute respirator and surgical mask are useful for meaningfully to the risk of COVID-19 among containing exhaled air, however the surgical HCP providing care to infectious patients, mask does allow more lateral escape.16 The motivating the use of respirators to prevent other options, fi nding more frequent appli- occupationally acquired infection”. cation in the healthcare industry, are the There is advice to the contrary. The fi ltering face piece types, the half face air World Health Organization (WHO)12 notes purifying respirator or the powered air-puri- the complexity of transmission routes, fying respirator, the latter having an APF of SARS-CoV-2 being primarily transmitted up to 1,000 and being used during high-risk aerosol-generating procedures.17

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We advocate an RPE programme, so Having said that, there have been several what should this include? Howie18 sets out trials comparing infection rates in healthcare a number of steps to construct an effective workers using surgical masks and or N95 programme, these being: respirators, but a meta analysis showed 21 • no difference, the authors suggesting that compliance with N95 masks may have been • (if practicable) a problem. The effect sizes were also small • technical controls and the samples not large enough to say if • identifi cation of those remaining there was any difference at all. vulnerable The risk does nevertheless need to be • information and informed consent to managed. Modelling data shows that the risk inhalation route of exposure is likely to be • select respiratory protective important, that respirators may be needed, equipment (RPE) adequate to control and that PPE is part of a suite of protective residual risk measures. The implications of the limited fi ltering capacity of the P2 respirators • involve wearers in RPE selection and including the N95 are that a choice of the match RPE to wearer higher grade of disposable respirator, or • fi t testing (to determine the RPE that even the more complex respirators such as gives the maximum protection) the air purifying respirator or the powered • test RPE in use (ie, the wearer can air purifying respirator should be available still achieve the required work task) for high-risk procedures, or failing that, the including compatibility with other higher grade of disposable fi ltering face pieces of ppe or task equipment piece respirator. These have been used (gowns, eye loupes etc) successfully in previous viral epidemics21 • train wearers, supervise in use (eg providing that training is effective. Although donning and doffi ng) available and quite widely used in industry, • minimise wear periods these appear to have had limited availability to HCWs in New Zealand. • maintain and audit RPE Having provided adequate RPE, it must As alluded to above, Howie further qual- be incorporated into a programme, starting ifi es the use of respiratory PPE by pointing with fi t testing. As far as we can determine out that manufacturers stated NPFs are from our own experience and our occupa- many orders of magnitude greater than tional physician colleagues there were no the workplace protection measured in the comprehensive RPE with an adequate “fi t workplace, the assigned protective factor. testing programme” as recommended by The protection offered by RPE, and indeed the New Zealand Australian Standard prior all PPE, degrades when in real use, as shown to the pandemic,2 these programmes should for leptospirosis but also likely to occur have been in place well in advance of any in healthcare—particularly, for example, epidemic, again in our opinion ‘normalised’ when subject to the hurly burly of physically into the healthcare worker induction and intensive work such as might occur during ongoing certifi cation programmes, as resuscitation, high-intensity nursing or some required for cardio pulmonary resuscitation, orthopaedic procedures. and, as with clinical skills, subject to audit. In our experience as occupational health Behavioural measures are also essential. physicians either working in, or offering As the risk of contamination when doffi ng advice to, district health boards, it is our the high-end equipment, or indeed any RPE considered opinion, shared by Agius19 and emphasises the need for training, we would others, that the use of surgical masks has endorse Howie’s18 and the CDC’s22 recommen- little place in a respiratory PPE programme dation of a “change supervisor” (themselves for HCWs. Surgical masks may have some use wearing appropriate PPE) to assist—and in diffusing the exhaled cough jet stream,16 insist on observing the correct technique. that is they are better placed on the patient rather than the staff member, but have no There are some very valuable occupa- place as RPE, as they cannot be fi t tested, a tional health lessons to be learned from view re-iterated by the manufacturer.20 the New Zealand COVID-19 response, the

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emphasis on surgical masks and N95 respi- • training in the correct use and mainte- rators also obscured other hazard control nance of RPE issues. For example facilities should be • ensuring RPE is correctly used, that is designed so that cross contamination is supervision minimised by careful attention to detail, for • fi t testing and fi t checking example sound design of patient fl ow and the provision of negative pressure areas to • inspection, maintenance and repair meet the expected clinical demand. of RPE Work practice controls must be improved • correct storage through attention to information and • keeping records training, the effect of possible failure having • audit been demonstrated in at least one district To be effective, as with all complex health board.23 The evidence supports this: medical procedures, an adequate respi- well equipped and practised high care ratory protection programme requires that units provided better protection for HCWs the HCW is deployed in a safe environment, than found in the less prepared general using appropriate equipment and tech- healthcare and home settings. niques, and has the resources and training Our model of a good respiratory to apply those techniques to their everyday protection programme therefore draws practice. This should be considered as a heavily upon Australian practice, in component of staff welfare, which, in an particular the Queensland Workcover audit of DHB plans, was the most poorly guidance,3 to ensure compliance with the addressed.24 We should also bear in mind relevant standards including: that, in the run up to the Rugby World Cup • correctly selecting appropriate RPE ‘well prepared’ acute care providers were (that is the right type of RPE for the signifi cantly less likely to respond to an identifi ed risk to staff) infectious disease outbreak.25 We need to • medical screening of RPE users give them the confi dence to do so.

Competing interests: Nil. Author information: Chris Walls, Occupational Physician, Counties Manukau Health, Auckland; Geraint Emrys, Occupational Physician, MidCentral , Palmerston North; Siobhan Gavaghan, Occupational Physician, Counties Manukau Health, Auckland; Des Gorman, Faculty of Medicine, Auckland University, Auckland; David McBride, Preventive and Social Medicine, University of Otago, Dunedin; Dave McLean, Senior Research Offi cer, Massey University, Centre for Research, Wellington. Corresponding author: Dr Chris Walls Occupational Physician Counties Manukau Health, Auckland. [email protected] URL: www.nzma.org.nz/journal-articles/a-model-respiratory-personal-protective-programme-for- the-new-zealand-healthcare-industry

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