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Introduction

The Hazardous Area Response Team (HART) has formed part of the multi-agency operational model for the last 10 years.¹ Prior to this, ‘hot zone’ working was led solely by fire rescue services with no clinical intervention in this area. Development of legislation has continued to put an onus on ‘responsible bodies’ to deliver the highest standard of care for people in environments that pose hazards to rescuers and the public alike. Coupling case law, informing the tort of medical negligence and modern medical ethics of non-maleficence², there is a heavy responsibility for prehospital providers to deliver care in these environments regardless of challenges they may pose.

With chemical incidents in civilian practice being rare,^3,4 it is assumed there will be little evidence and literature available that assesses the impact of Personal Protective Equipment (PPE) on patient care.  However, the use of simulative pedagogy, in modern medical practice, allows the safe testing of equipment and procedures subsequently supplementing the available literature.

This review aims to probe the literature beyond the confines of medical research to establish the facts surrounding the use of PPE (Specifically Chemical, Biological, Radiological and Nuclear protective PPE: CBRN) and how this affects emergency service personnel. It is essential we understand how PPE impacts emergency service personnel in the course of their duties.  If it is shown that PPE negatively impacts clinical skills such as intubation or cannulation then prior planning, training, standard operating procedures, and guidance is required to counter this to uphold the rights of patients, with an evidence base to underpin this. The review follows the PRISMA structure for reporting of systematic reviews.

Methods

The patient/population, intervention, comparison and outcomes (PICO) format was used to construct the research question:

‘In the adult population injured in hazardous circumstances, is the standard of clinical care affected when compared between PPE and non-PPE wearing clinicians?’

Eligibility was based on articles measuring the effect PPE has against a control group of no PPE published since the year 2000.  Groups outside of healthcare were included due to the relative youth of HART and this style of working within healthcare.  Studies were not limited to any specific skill or task to allow broader inclusion and build an overall understanding of how PPE effects emergency personnel to allow consideration of human factors.⁵ Only open access articles were reviewed, allowing a full review of the articles.  Non-English studies were excluded to ensure key messages are not lost in translations. Publications older than the year 2000 were excluded to ensure current practice is used. Otherwise, if upon review of title, abstract or article, they were found to not make the aforementioned comparisons, they were eliminated from this review.

Articles were critically assessed using the Critical Appraisal Skills Program (CASP) checklists⁶ for systematic reviews and cohort studies relative to the shortlisted articles facilitating a consistent approach to assessing each article and to reduce bias from researchers. Findings were reported using the PRISMA framework.⁷

Databases were searched in June 2022 by both researchers and results can be seen in Figure 1.

 

Figure 1. PRISMA Flow Diagram adapted from Page et al⁷.

 

These databases gave access to literature both inside and outside of medical research to allow inclusion from other emergency services and military databases which include more historical exposure to the use of PPE. Search criteria was: “CBRN” AND “PPE” AND “Performance” within the title fields only with a years filter of 2000-current.

Duplicate titles were not removed at the initial stage as a method of self-checking. The exclusion of titles and abstracts was completed manually by two researchers. A third impartial reviewer was available to settle disagreements; however no disagreements arose. Titles and abstracts were eliminated from each database, based on a manual check, against the search and eligibility criteria on review. Inconsistencies in the method could be detected if a title or abstract was to be eliminated in one database but not another; no such inconsistencies were detected ensuring a consistent method. Identified duplicate titles were removed in the last stage.

Shortlisted articles seen in Tables 1 and 2 below, were then grouped into homogenous cohorts to extrapolate comparable quantitative values and can be seen in Table 2. Qualitative themes were extrapolated by a single researcher in a reflexive thematic analysis style⁸ and identified themes are discussed below. These themes were retrospectively discussed with the second researcher, who agreed on the themes.

 

Table 1. Shortlisted literature review articles

 

Table 2. Homogenous results

 

Results

Of the shortlisted articles, eleven are primary research simulation studies, two are systematic reviews and one was a research masters thesis. These studies are predominantly in the medical field (n=11) with the remainder coming from policing (n=2) and the military (n=1). No studies were identified from fire services. The primary research spanned North America (n=3), Europe (n=5), Asia (n=3) and Africa (n=1) demonstrating a heterogenous spread of healthcare systems and economies.  However heterogenous the geography of data sources, consistent approaches to PPE allow comparison across the research articles. PPE classifications seen in table 3 can either be graded as per the National Fire Protection Association Standards (NFPA), class 1 to 4, or by the American Environmental Protection Agency (EPA) class A to D. NHS HART often refers to PPE classifications in line with EPA standards and this is reflected in the majority of the articles.

 

Table 3. PPE Classifications and descriptions⁹

 

Table 1 uses Dougherty and Conway’ s system of translational research¹⁰ to compare articles as a simple way to demonstrate the power of each article in a numerical scale from 1 (lowest) to 3 (highest). This tool allows a comparison of the shortlisted articles and demonstrates how they either impact current clinical practice (translational level) or the likelihood these simulations would influence practice.

Simulations studies involved in the review are at low translational levels. However, with little incidence of patient illness requiring Levels A, B and C PPE, ⁹ it is unlikely there would be articles assessing simulative training impacts above the lower translational levels.

Figure 2 shows a summary of the data from Table 2.

 

 

Qualitative data was also collected in several studies.^{12,16–18,20,22,24} Common themes were:

Dexterity: PPE reduced dexterity particularly the hands and wrists making tasks such as intubation or cannulation difficult.^17,22  Kou et al¹⁸ noted it is obvious participants were finding it more difficult to move while wearing PPE.

Vision: Participants identified vision was reduced especially in respirators with limited visual fields.^17,22

Higher exertion and increased fatigue: Participants felt fatigued whilst wearing PPE.^12,16,24 Two studies stopped participants from completing the full study due to rising body temperatures.^12,24  Rising temperatures inside the PPE was observed in one other study.²⁰

Communication: A single study discussed how communication was impaired through voice muffling and noise from powered respirators creating obvious limitations when compared to no PPE.²⁰

Kou et al¹⁸ measured perceptions of PPE before and after their PPE simulation showing improvement in how severely the perceived impact would be. They noted that training boosted participants’ confidence.

Wang et al²² showed how the above themes were prevalent among their participants. However, half or less of the participants felt PPE affected vision and dexterity while performing tasks compared to no PPE. This suggests that even though it is a reported issue, it was not for a significant portion of participants, contrary to other studies.

Critical appraisal of included studies

The CASP tool⁶ was used to assess articles. Significant flaws were found throughout the simulations which commonly referenced each other or their own work, reinforcing the risk of bias.^{11–18,20,22,24}  The two included systematic reviews^19,23 that also reference these key flawed studies in their evidence. These themes are discussed below.

Study designs: Three of the articles ^13–15 shortlisted in this review were by research teams led by Nicholas Castle. A futher four shortlisted articles^17,18,19,23 referenced the three Castle et al articles. Of the remaining four, three were focussed on law enforcement^12,24 or military personnel²¹, and as such, were unlikely to reference this ‘healthcare-focused’ work. This means articles from this single author^13–15 makes up or impacts approximately 75% of the evidence. But the design of one of the studies¹⁴ is flawed, which should invalidate the applicability of the results to practice. Furthermore, when this work is referenced in systematic review, subsequent researchers claim to have only included articles where ‘users have experience of wearing PPE’¹⁹ or studies that ‘mimicked realistic situations’²³; bringing into doubt the authors understanding of this equipment use or its application. The issue is that the problematic article¹⁴ used students as participants, but they’re referred to as ‘experienced and this article employs PPE not in line with current guidance’. Additionally, when referring to studies that only mimicked realistic scenarios the majority of simulations studying time-affect, laid equipment out prior to starting and ran simulations in a hospital environment.^{13–15,18,20,22} Meanwhile other studies measuring resuscitation involved solo rescuers or doing compressions on the floor, which is contrary to current standard procedures.^16–18 This remains exceptionally pertinent as to sit, kneel or lay on the floor to deliver these skills or interventions would compromise the integrity of the PPE and so would not be done in practice, so testing the effect of PPE on compressions while kneeling would not be applicable to practice.

‘Experience’: Several studies compare levels of experience.^{15,18,19,21,22}  However, only one study considers experience of wearing PPE,¹⁸ while the remaining articles considers experience based on years served or clinical seniority.^{15,18,19,21,22} Often these comparisons are between anaesthetists, especially when referring to intubation. However, these authors do not consider the need for experience of operating in PPE and how this impacts performance.  ‘Experience’ was shown to reduce error,^15,20,22 however there is philosophical debate around what defines experience in this environment.

Results: Some articles state they were unable to finish their study as participants breached safety cut-offs and had to stop,¹² this could have impacted the result. Small participant numbers also reduce reliability.^12,17,20,21 Otherwise, wide standard deviations seen above in Figure 2 suggest the need for larger sample sizes.¹⁷

Generalisability to prehospital practice: Often studies focused on a hospital environment.^{13–15,18,20,22} With only one study employing a pre-hospital approach to their study design,¹⁶ it is unfortunate that participants were doing resuscitation while on the floor in PPE.¹⁶

Discussion

CBRN-PPE has negative effects on clinical skills, predominantly intubation and skills requiring finer dexterity, such as cannulation.^{11,13–15,17–23} Regarding resuscitation,²⁵ it is shown that PPE negatively impacts compressions.^16,17 This is compounded by the impact on fatigue.^12,24 However, this evidence is brought into doubt by multiple flaws,^{15,18,19,21,22} and misunderstandings of correct application of PPE.^14,19

Industrial accidents or acts of chemical-based terrorism may require high levels of PPE and clinical care, justifying the need to maintain this capability and protect rescuers.^3,4,26 Especially in cases with deteriorating patients, delays in definitive care during lengthy decontamination processes (that are required to prevent secondary contamination of rescuers and forms an essential part of patient treatment) must be considered as part of ongoing care.^1,27

Legislation balances the rights of rescuers and victims while placing a duty to deliver prompt care^25,28,29; given this, it is not as simple as removing the capability/duty on the basis it is difficult to deliver, frequency of use or concepts of expertise. Therefore, while guidance²⁵ built on evidence of survivability supports delivery of ALS with toxic causes, consideration needs to be granted to the impact of PPE on specialist paramedics’ ability to deliver these specific skills.

Common reference to experience, based on clinical seniority or number of years served shows little consideration towards how experience of operating in PPE¹⁸ is a key confounder, especially in the light of human factors being a leading risk to patient safety.^30,31  Experience is far more complex than ‘years served’.⁵ Operating in these PPE must always be done in a team further compounding the difficulties therein.⁵ Teamwork and human factors elements are under-assessed in the review and this shows a significant absence in the literature. Simulative methods³² should be applied in the future to looking at how this level of PPE impacts team factors.

The literature carries little applicability to prehospital practice.  The simulations operated in hospital environments or laid equipment out prior to starting.^{13–15,18,20,22} Further to this, study designs either led to compressions being done on the floor ^16–18 or in positions that simply would not be employed due to the limitations of PPE.^13–15 This highlights an area that needs further investigation through teams that are experienced in the use of PPE.³³ These teams need to pioneer the research into this specialty field, giving credibility behind the results and employ studies that are realistic within the confines of the PPE. Consideration should be given towards human factors to increase patient safety ^30,31 and how the PPE limits these elements, alongside impacts on specific clinical tasks. Guidance on care in these environments can be generated with consideration towards impacts of PPE on clinical care balancing the protection of wearers²⁹ with the rights of victims.²⁸

Limitations

Searches were limited to articles only written in English which would eliminate research in other languages that may investigate more recent wide scale chemical weapons use.^34,35 ‘Years’ filters removed any research from incidents of historic use where research could be found outside of simulation.^27,36,37 The articles had a heterogenous pool of data which limited the ability to perform a statistical meta-analysis and establish statistical significance. Lastly, because of the variety in PPEs within the found literature and limited comparisons between similar PPEs it is not possible to draw conclusions as to whether there is a correlation between level of PPE and level of impedance of each skill set.

Conclusion

This review searched seven databases looking for evidence outside of and including the medical literature to establish the effect PPE has on wearers in the delivery of tasks. Most evidence is simulation-based which would align with the low incidence of work requiring this level of protection. PPE had negative impacts on wearers’ ability to deliver key clinical skills associated with advanced life support and increases fatigue.  This is demonstrated through PPE having a negative effect on specific skills (such as intubation, IV cannulation and chest compressions), when compared to non-PPE groups. However, the evidence has significant flaws affecting its credibility and applicability to the prehospital environment. There is an established gap evidenced from this review on how PPE can affect the delivery of ALS in the prehospital environment and further assessment of human factors is required.

Conflicts of interest 

Author is a UK HART Paramedic

Ethics 

Ethics were approved as part of Queen Mary University ethics approval process reference QMERC22.264.

Funding 

None, this forms part of a self-funded Masters project in prehospital medicine with Queen Mary University, London.

Acknowledgements

The authors would like to thank Dr Gareth Grier and Amy Hughes for their supervision with this project, Dr Shadman Aziz for critical feedback on this manuscript and Dawn Anderson for her continuing support.

Author(s)

Tim Anderson*¹, Conrad Boddington^2
1Hazardous Area Response Team (HART) Paramedic, Hazardous area response team, UK
²MSc Trauma sciences, Queen Mary University, London
*Corresponding author email tim.anderson@eastamb.nhs.uk

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