Limiting factors for wearing personal protective equipment (PPE) in a health care environment evaluated in a randomised study

Pandemics and re-emerging diseases put pressure on the health care system to prepare for patient care and sample logistics requiring enhanced personnel protective equipment (PPE) for health care workers. We generated quantifiable data on ergonomics of PPE applicable in a health care setting by defining error rates and physically limiting factors due to PPE-induced restrictions. Nineteen study volunteers tested randomly allocated head- or full body-ventilated PPE suits equipped with powered-air-purifying-respirators and performed four different tasks (two laboratory tutorials, a timed test of selective attention and a test investigating reaction time, mobility, speed and physical exercise) during 6 working hours at 22°C on one day and 4 working hours at 28°C on another day. Error rates and physical parameters (fluid loss, body temperature, heart rate) were determined and ergonomic-related parameters were assessed hourly using assessment sheets. Depending on the PPE system the most restrictive factors, which however had no negative impact on performance (speed and error rate), were: reduced dexterity due to multiple glove layers, impaired visibility by flexible face shields and back pain related to the respirator of the fully ventilated suit. Heat stress and liquid loss were perceived as restrictive at a working temperature of 28°C but not 22°C.


Introduction
Within the framework of the Campus project of the Medical University of Graz a joint laboratory for working with biological agents in risk group 3 is designated for the Institutes of Pathology, Hygiene, Microbiology and Environmental Medicine and Biobank. In the context of healthcare and medical diagnostics the mentioned unit should enable a safe and immediate execution of autopsies and sample collection to research pathogen-host-interactions. To be able to work on pathogens causing diseases with pandemic potential as well as therapy resistant pathogens whose risk group is unknown, the laboratory should additionally be equipped with a mobile isolation unit (glovebox) and should furthermore include increased personal protection. This kind of sample collection is currently not organised but is highly relevant to determine whether mortality can be traced back to the agent or to comorbidities when diseases caused by pathogens are occurring. Furthermore important information concerning the organ specifity of pathogens, pathogenic mechanisms, as well as the body's infection defense reactions can be gained.
The establishment of such a sample collection centre takes places within the framework of a pan-European infrastructure initiative of the European Commission (ERINHA = European Research Infrastructure on Highly Pathogenic Agents). One of the tasks linked to this project is the establishment of a master plan for an all-purpose sample collection during autopsy. This concept should be set up at the interface between the health system and high security laboratory and should be an appropriate mock-up solution for all of Europe. For this reason a mobile solution especially applicable in countries with a warmer climate (e.g. South-East-Europe, Africa) is required. The planning takes place in close collaboration with the High Infectious Disease Transport Team (HITT) of the Red Cross Styria, as well as the the Provincial Health Directorate Styria and the Department of Civil Protection Styria.
Beside safeguarding human beings and environment from unintentional disposal of pathogenic agents it is important to protect laboratory staff from infections. To ensure sufficient protection the following safety precautions are intended: 1. Spatial infrastructure: laboratory with security level 3 2. Room setup: gloveboxes with negative pressure and material lock, manlocks with opportunity for decontamination 3. Personal protective equipment: virus-tight-whole-body protective suits, respiratory devices with HEPA filters, virus-tight gloves and boots

Objective of the study
This study focuses predominantly on barrier level 3. Aim of the study is to identify how wearing PPE over a longer period of time in different temperature conditions affects physical performance, individual feeling, power of concentration and error ratio (elevated environmental temperature could pose a limiting factor while working with increased personal protection). Furthermore it raises the question of which possible maximum working timeis feasible. It is to assume that raising the time limit implicates higher error ratio, followed by the fact that protective provisions can't be met, which furthermore highly increases risk of injury. For this reason it is important to identify indicators that point out loss of concentration in a timely manner.

Study design
This study is planned as a monocentric, randomised cross-over study. During the course of the study, two protective suits will be compared under two different temperature conditions. This study serves to determine the bodily performance, the concentration levels, error rates, and subjective well being during laboratory work in protective suits. A pilot phase is planned, in order to optimise the simulated laboratory work in glove boxes, to define the most meaningful simulated conditions (e.g., how many pipetting steps are possible in a given time, testing the logistics during the procedure), as well as to determine the relevance of the planned measurements. In the pilot phase, between 5-7 voluntary test subjects will be included. Based on the evidence from published studies regarding testing of personal protective equipment, a participant number of maximally 20 is assumed, although, due to the relatively long time required for the study, a dropout rate of about 50% is to be expected.

Study population
The study is split into a pilot and execution phase, where 5-7 voluntary subjects are included in the pilot phase and a maximum of 20 voluntary subjects are included in the execution phase. The recruiting for the trial is exclusively carried out on a voluntary registration base through announcements at KAGES, the Medical University of Graz, the Karl-Franzens University and the University of Applied Sciences JOANNEUM, mainly focused on students and employees from the above mentioned institutions. The inclusion and exclusion criteria below are taken into consideration.

Methods
Each participant tested two PPE systems: a) system A: full-body suit including respirator -e.g. Tychem F protective suit including socks -e.g. 3M TM reusable light cap S-655 -e.g. 3M TM Jupiter TM cooling unit -e.g. Sempermed surgical gloves (optional) -e.g. boots b) System B: full-body suit with fully integrated ventilation system (positive pressure) -e.g. 3M TM JS-series Typ 3 Respiratory Protective Suit (CRPS) -e.g. Sempermed surgical gloves (optional) -e.g. boots at two different climate zones (module I: ~ 20°C / module II: ~ 28°C) on two different days. On each testing day between two and four subjects perform the series of testings listed below. Each subject is assigned through a system of randomisation called http://www.randomizer.at/, which decided with which PPE system the subject is supposed to start the testing series.
The test series described below are run in succession where the test persons start in a time-delayed fashion. After 15 minutes, they change to the next test. Between the various tests, there is a five-minute recreation break. Tests 1-3 are repeated until the test person cannot tolerate the conditions any more or stops for another reason During the test phases the following parameters are measured and recorded regularly: heart rate, heart rate variability, oxygen saturationand body temperature. Immediately before and after the separate modules urine and saliva specimens are taken in order to create a metabolite profile, and the weight of the body and the equipment are measured in order to be able to calculate the loss of fluids. In addition to the measurements mentioned above an extensive instruction, explanation and anamnesis will happen before the study starts. The test persons are encouraged to comment on their subjective feelings during the test series, furthermore there is an hourly survey by way of a structured questionnaire (including a continuous record on the communications system).

MODULE I a/b (environmental temperatures ~ 20°C) Test Task
Type ( Evaluation based on subjective judgement c) Optimizing the study protocol based on the results of the pilot phase

II EXECUTION PHASE a) Conducting module I a/b + II a/b Preparation
Issuing a subject-ID Issuing the randomly assigned PPE system Short introduction -> Only for the first appointment (getting dressed, explaining the testing series,…)

Initial measurements (immediately before starting the testing series)
Anamnesis ( Laboratory tutorial II (duration: 15 minutes + recovery period: 5 minutes) Recording measured data (HR, oxygen saturation, °C) Power of concentration test (duration: 15 minutes + recovery period: 5 minutes)

Final measurements (immediately after finishing the testing series or after quitting the testing series)
Measuring the total weight (subject including the protective suit) Taking off the protective suit Measuring body weight (without PPE system) Measuring weight of PPE system Removing the HR-monitor/pulse oximetry Removing the thermometer Collecting saliva samples -> refrigerated storage Collecting urine samples -> refrigerated storage Measuring HR (recording in the database) Measuring oxygen saturation (recording in the database) Measuring body temperature (recording in the database) Measuring blood pressure (recording in the database)

b) Data interpretation
Exporting coded subject data from Microsoft Access to Microsoft Excel Forwarding the coded data to the statistician Interpreting the generated data Developing the publication Releasing the publication to a scientific journal / dissertation

Study dropout
Each subject is able to quit the study any time (reasons are not required, but can be mentioned). Module I with an environmental temperature of about 20°C automatically ends after a maximum 6 hours. Module II with an environmental temperature of about 28°C automatically ends after a maximum of 4 hours.

Therapy safety
There is neither a benefit nor a risk for subjects included into the trial. Due to the water tightness of the protective suits used in the study strains like heat accumulation and fluid loss through heat generation inside the suit could lead to cardiovascular problems (e.g. to collapse) under certain circumstances. For this scenario a medical doctor on call-duty is contacted immediately. Apart from that, there is no further risk to be expected for the described trial.

Data management
Data management of the subject's data is exclusively made in a coded way with help of an access database, built up on the following scheme: Body weight in g Body weight in g Body weight in g Weight of suit system in g Weight of suit system in g Weight of suit system in g Weight of suit system in g Total weight in g Total weight in g Total weight in g Total weight in g dehydration in g dehydration in g dehydration in g dehydration in g To guarantee a regular contact with the study subjects (for the different testing series) contact details in connection with a subject-ID are recorded in a separate, password protected database.
contact data subject-ID title surname family name Email address phone number notes

Ethical aspects
Regarding benefit or risk for the subjects, see Therapy Safety above. For clarification of all ethical aspects an application to the ethical commission of the Medical University of Graz is made. All subjects are instructed at an informal meeting (repeated if required) where the informed consent paper is provided.

Data protection
Individual-related information connected with data generated within the study is exclusively saved in a coded way in a database with restricted access and own passwords. For contacting the subjects a separate contact data base with restricted access and own password is established. The generated data for analysis, publications and exchange with the collaboration partner is exclusively used in a coded way. Furthermore it is ensured that results of the trial (e.g. performance of the testing series) has, where appropriate, no influence on a current employment relationship or studies.

Estimated number of cases
The number of cases of about 20 subjects is estimated on the basis on findings of previous trials regarding testing of PPE. Due to a relatively high time requirement to go through the trial a drop out rate of about 50% is expected.

Reporting
The outcome is intended to be published in scientific journals, in a dissertation, as well as to be presented at congresses.