|Year : 2020 | Volume
| Issue : 7 | Page : 22-30
Personal protective equipment during COVID-19 epidemic
Dhiren Gupta1, Ashish Kumar Simalti2, Neeraj Gupta1, Anil Sachdev1, Arun Bansal3, Ashwani Kumar Sood4, Tripti Sharan5, Vinayak Patki6
1 Department of Pediatric Critical Care, Sir Ganga Ram Hospital, New Delhi, India
2 Department of Pediatrics, Army Hospital Research and Referral, New Delhi, India
3 Department of Pediatrics, Division of Pediatric Critical Care, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
4 Department of Pediatric Medicine, IG Medical College, Shimla, Himachal Pradesh, India
5 Department of Gyneacology, BLK Super Speciality Hospital, New Delhi, India
6 Department of Pediatric Intensive Care, Advanced Pediatric Critical Care Centre, Wanless Hospital, Miraj, Maharashtra, India
|Date of Submission||24-Apr-2020|
|Date of Decision||30-Apr-2020|
|Date of Acceptance||03-May-2020|
|Date of Web Publication||29-May-2020|
Dr. Ashish Kumar Simalti
Army Hospital Research and Referral, New Delhi - 110 010
Source of Support: None, Conflict of Interest: None
Personal Protective Equipments (PPEs) are used to safeguard the health of workers. Airborne aerosol with size below 5 micron can enter lower respiratory system directly whereas bigger size particles either settles on surrounding equipment and become fomites. COVID 19 can stay in air after 3 hours with airborne spread in health care with fomites especially plastic showing infection up to 72 hours. Examples of PPE include items as mask, gloves, shield, goggles, gowns and full body suits. All health care workers need to be taught the correct sequence of wearing and taking off the PPE in order to avoid contamination.
Keywords: COVID 19. N95 respirator, doffing, donning, personal protective equipment
|How to cite this article:|
Gupta D, Simalti AK, Gupta N, Sachdev A, Bansal A, Sood AK, Sharan T, Patki V. Personal protective equipment during COVID-19 epidemic. J Pediatr Crit Care 2020;7, Suppl S1:22-30
|How to cite this URL:|
Gupta D, Simalti AK, Gupta N, Sachdev A, Bansal A, Sood AK, Sharan T, Patki V. Personal protective equipment during COVID-19 epidemic. J Pediatr Crit Care [serial online] 2020 [cited 2021 Oct 26];7, Suppl S1:22-30. Available from: http://www.jpcc.org.in/text.asp?2020/7/7/22/285381
| Introduction|| |
The knowledge of transmission pathophysiology is very important as it will help not only in selecting appropriate protective equipment but also decide the duration of protection. COVID 19 is new to this world therefore exact mechanism of transmission is not known and changing every week as per emerging research. Although it behaves like droplet infection in community but in hospital especially areas where aerosols are produced (intensive care unit) it produces droplet nuclei which spread quite far. Therefore, areas where intubation and procedures such as manual ventilation, suctioning, nebulization, cardiopulmonary resuscitation, bronchoscopy, throat examination, endoscopy, and autopsy being done we need to take special precautions meant for airborne spread.
| Personal Protective Equipment|| |
Preventing the spread of the SARS-Cov-2 virus from man-to-man is the only way to effectively control this pandemic. The chain of transmission through the aerosol droplets and physical contact has to be stopped. Personal protective equipment (PPE) is important component to not only protect health-care worker (HCW) but also patient-to-patient contamination. Examples of PPE include such items as mask, gloves, foot, and eye protection (shield and goggles), gowns, and full body suits. The example of a heath-care worker wearing full PPE is shown in [Figure 1].
|Figure 1: A health-care worker in full personal protective equipment and coverall|
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| Masks|| |
Dust mask is a disposable, molded face mask made of paper pad. It is worn for protection against nontoxic dust. It does not offer any protection against airborne pathogen [Figure 2]. Single layer face mask which consists of a single layer of wood pulp tissue paper or nonwoven fabric. It is also not recommended for protection against coronal virus transmission. Cloth masks although not very effective for protection against corona virus may be worn by general public, in places where risk of transmission is low. Cotton masks are available in market and can even be made at home. A manual for making home-made cloth masks has been released by the Government of India has recently. This manual advises use of 100% cotton material like old T shirt or cotton vest. Two to three layers of cloth is optimal as increasing layers can improve efficacy but it makes breathing difficult.
Surgical mask is worn most commonly in health-care settings. Surgical mask consists of three layers [Figure 2]. The inner layer has absorbent property to absorb moisture from exhaled air. The middle layer acts as a filter and it is made up of nonwoven mat of thin fiber or melt-blown material. The outermost layer repels liquid. These masks have pleats to increase the surface area to cover the chin and nose. These masks are disposable and they do not fit tightly around face and nose.
Surgical mask prevents the release of respiratory emissions from the user into their immediate environment. The main purpose of wearing these masks is to protect patients or people nearby from the person wearing it and not the other way around. Although not protective to wearer against airborne infection because of their loose fit, they do protect the wearer from direct spray or splashes of infectious body fluids or blood. Surgical masks do not have safety rating but US Food and Drug Administration (FDA) requires them to conform to the certain quality standards. They should have bacterial filtration efficiency more than 98% and they should prevent more 99% particle size of 0.1 micron. During the influenza epidemic of 2008–2009, at least two studies have documented that surgical masks were as effective as respirators for prevention of influenza among nurses providing care., The WHO recommends face masks for people with respiratory symptoms or caregivers of symptomatic individuals.
Respirators differ from surgical masks in their fit. Unlike loosely fitting surgical masks they are tight fitting. Respirators are designed to create a facial seal to protect the wearer from airborne particles. They provide two way protection by filtering both outflow as well as inflow of air. They are available as disposable device and also as full face or half face respirator device. These respirators are given ratings based on the percentage of aerosol they can prevent from going through. Transmission prevention by N95, Surgical Mask and cotton mask has been documented to be 70%, 50%, and 40%, respectively while protection offered has been 99%, 75%–80%, and 50%–70%, respectively. N95 is recommended while collecting nasal or pharyngeal swab. HCWs looking after COVID-19 patient should wear a surgical mask but N95 along with other components of PPE, is a must for personal protection during aerosol generating procedure such as noninvasive ventilation, intubation, manual ventilation tracheostomy, cardiopulmonary resuscitation, and bronchoscopy.
Types of respirator
There are many types of respirators available in market which differs from each other in terms of their filtering capacity. Center for Disease Control (CDC) and European Committee for Standardization (CEN) have made scales of standardization for these respirators, based on their filtering capability. The mask with CDC 95 rating can collect at least 95% of the aerosol and does not allow it to pass through similarly CDC 99 rating means at least 99% aerosol particles getting filtered out and there are even respirators with CDC 100 rating which can filter almost 100% (practically up to 99.7%) of particles in the aerosol, wearer is breathing through. Oil can impact the efficacy of the filter used in these masks as electrostatic charges in the filter media can change on contact with oil. Thus, in industries, where exposure to oil is common, respirators need to be made resistant to oil too. This gives rise to another rating based on permeability of oil. These are N meaning not resistant, R meaning resistant but not absolute while P meaning oil proof or strongly resistant. With these two properties, the level of resistance to oil and percentage of particles filtered these respirators can be divided into 9 categories in CDC standard. These CDC categories are N-95, N-99, N-100, R-95, R-99, R-100, P-95, P-99, and P-100. CDC has advised that N95 respirator should be considered as standard part of the advised protective equipment in their Covid-19. CEN uses another system namely filtering face piece (FFP). With ratings of P1, P2, and P3 which depends on filtering capacity of 80%, 94%, and 99.95% particles, respectively. Hence, the standard N95 of US FDA is equivalent to FFP2 of CEN. [Figure 3] shows some of the US FDA and CEN certified respirator masks.
|Figure 3: Comparison of N95, N99, and N100 with FFP2, FFP3, and P3 respirator masks|
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Valved and non valved respirator
As the filtering capacity increases, the passage of air through filter also becomes difficult. This makes it uncomfortable for the wearer to breathe through these respirators especially with N100 or FFP3 masks. In order to make them convenient to user some respirators have expiratory valve included in the respirator. This is more comfortable as it makes it easier to exhale and also less moisture build up inside the mask which can be very uncomfortable to wearer for long duration. However, as the exhaled air is not passing through the filter but getting out through the valve, it does not protect the environment if the person wearing this mask is already infected by respiratory pathogen needing use of this kind of protective device. Every time, the person coughs/sneezes the exhaled pathogens come into environment through the valve bypassing the filter [Figure 4].
Powered air-purifying respirator
These respirators are supposed to be more comfortable for the person wearing it as they reduce heat related stress. A battery-powered fan is used in these respirators to make air flow through a filter which makes breathing easier. These respirators appear to be more protective than disposable N95 respirators but there is no clear evidence for this. PAPRs are expensive thus may not be an option in the current pandemic other limitations are difficulty in communication because of noise of the fan and risk of contamination during doffing. It is recommended that an expert staff should assist HCWs in doffing process [Figure 5].
The National Institute for Occupational Safety and Health (NIOSH) approves all respirators used in health-care settings to ensure standards of quality and performance. Only NIOSH authorized manufacturer can use the NIOSH logo or NIOSH name in block letters or on respirator. An established quality program to ensure respirator meeting the NIOSH requirements is expected from manufacturer. Markings of NIOSH logo or name may be on the front or on the straps. Counterfeit respirators with NIOSH name or logo are often sold in market and they may be available at lower prices. NIOSH website has list of approved respirators and if NIOSH level is on the respirator but the name of manufacturer is not on the list, it may be a counterfeit product. There is also a TC number given by NIOSH and with the help of TC number, buyer can verify this at the website:-http://www.cdc.gov/niosh/npp tl/topics/respirators/disp. TC number should be clearly marked on the packaging, on the respirator and also on the user instructions.
Seal test and fit test
Occupational safety and health administration have issued guidelines for testing these respirators with seal test to be performed every time person wears it and fitting test is done for nonexpendable respirators once in a year. The user must perform a seal check after wearing the respirator. This test can either be a positive or negative pressure check. To perform positive pressure seal check, person exhales gently after wearing the respirator and the face piece should be slightly pressurized before elevated pressure causes leakage. During, similarly for a negative pressure check face piece should collapse slightly when person inhales sharply. This procedure is called seal check and is different from a fit test. Fit test is performed by manufacturer before releasing respirator in market while seal check is performed by the user. However, many times these terms are used interchangeably.
Facial hairstyle and respirator
Facial hair such as sideburns, some mustaches and beards, can interfere with the sealing area of a respirator. This may lead to failure of creating a tight seal to achieve maximum protection. Small particles in the air take the path of least resistance and through facial hair can bypass the filter of respirator. Hair is much larger in size and not dense enough to act as an effective filter. Facial hair under the sealing area causes significant leakage when compared to clean-shaven person. Even 2 days, stubble can reduce protection. CDC has issued a figure showing different types of beard and weather they allow individual to wear respirator effectively or not [Figure 6].
Storage and reuse
Respirators or face mask should be stored in a container made of material that allows breathing like paper bag. The name of user should be placed on the respirator or face mask as well as storing container to prevent reuse by another person. Name on mask can be written on the straps of respirators. Date and time should be written on the container bag to track duration of use.
Reuse of disposable surgical masks is common in the time of scarcity, but there is no recommendation for this and it may even increase the risk of infection. Recommendation has been issued for limited reuse or extended use of disposable respirators and masks. Reuse of these disposable protective devices is not recommended if they were used for any procedure which may result in aerosol generation such as suction, intubation, and bronchoscopy. Respirators should be discarded if seal is not adequate around mouth and nose. With extended use respirator gets moist from exhaled air or sweat and in that event it is considered to have reached end of its life. Respirator should not be reused if it is soiled or damaged.
Drying for at least 48 h kills the corona virus. Drying the used respirator in a clean, dry place for 3 days is one practical way of reusing the mask. AIIMS Delhi has issued a protocol for reusing based on this method in which all HCWs are issued 5 masks and 5 marked paper bags. They are supposed to use one mask a day and then keep it in the paper bag and use next mask for day 2 and so on for the next 4 days till by rotation number of first worn respirator comes. The paper bag should be kept away from direct sunlight and ultraviolet rays. If the respirator becomes damaged, soiled, or breathing becomes difficult, it is no longer fit to be used.
Heat in an oven
To heat the respirator at 70°C for 30 min, respirator can be hung in the oven using a wooden clip. It is important to confirm from manufacturer that if the material used for N95 is not inflammable. Similarly, many respirators have a metal clip for fixing at the nose which may melt in the oven hence respirators with metal clip should not be sterilized in this manner not only oven, even an electric rice cooker can be used without putting any water inside. In case of electric cooker, it needs to be kept for 3 min at temperature of 149°–164° centigrade.
Recently, there have been reports of using hydrogen peroxide for sterilizing used respirators. During 2009 Influenza epidemic, NIOSH had compared five methods of disinfection namely microwave oven irradiation, bleach decontamination, ultraviolet germicidal irradiation (UVGI), ethylene oxide (EtO), and vaporized hydrogen peroxide (VHP). Out of these UVGI, EtO, and VHP methods were found to be promising decontamination methods. Cleaning the mask with soap, alcohol, bleach, or isopropranolol has not been successful as they caused damage to the electrostatic charge thus significantly reducing the filtration capacity.
| Face Shield|| |
A face shield is classified as a PPE that provides barrier protection to the facial area and the related mucous membranes (eyes, nose, and lips). Face shields provide a barrier to a bout of suddenly expelled aerosol of body fluids and are commonly used as an alternative to goggles as they confer protection to a larger area of the face. The major structural components of a face shield include a visor which is the glass part of face shield. Ideally, width should be sufficient to reach at least the point of the ear [Figure 7]. The purpose is to lessen the chances of the splash to reach the eyes and oral cavity. A frame is required to hold visor in place. Face shield frames used in health care are generally made of lightweight plastic.
Face shield should be worn during patient care activities where splashes and sprays are anticipated, typically including aerosol generating procedures. Moreover, during activities where prolonged face-to-face or close contact with a potentially infectious patient is unavoidable. Face shields should not be used alone while intubating because aerosols can flow behind the visor hence goggles should be worn. Face shields and goggles should not be used together, as it does not offer additional protection. It causes more discomfort and fogging affecting vision except during aerosolization procedure as mentioned above.
Health-care provider should take care not to touch their eye protection. If they touch or adjust their eye protection, they must immediately perform hand hygiene. If they need to remove their eye protection, they should leave patient care area. Face shield should be taken off as late as possible, preferably at the end of the procedure to prevent inadvertent exposure of the mucous membranes when other potentially contaminated PPE components are being removed. Face shields with single Velcro or elastic straps tend to be easiest to don and doff. Doffing can be accomplished with a single hand. It should be discarded if damaged for example if face shield can no longer fasten securely, it should be changed hazards. The American National Standards Institute (ANSI) prescribes the design, performance specifications, and marking of safety eye and face products. ANSI/SEA Z87.1-2010 orEU standard directive 86/686/EEC, EN 166/2002 can be used till more evidence emerges for infections like COVID 19.
Combination of this face shield and an N95 FFP respirator (N95 FFR) protected the eyes, nares, and mouth from contamination better than if N95 combined with goggles. For droplet with size more than 5 μm, the efficacy is 96% (for aerosol spread from distance of 45 cm). If the droplet size is reduced to <3.4 μm, the efficacy goes down to 23% over 30 min postcough.
| Goggles|| |
Goggles should have a good sealing with the skin of the face. The frame should be flexible to easily fit all face contours without much pressure on the skin. It should cover the eyes and the surrounding areas (through the silicon rim) and accommodate the prescription glasses underneath. It should have a fog and scratch-resistant adjustable band that can be firmly secured and does not become loose during clinical activity. Goggles should have an indirect venting mechanism to reduce fogging. Goggles can be reusable (provided appropriate arrangements for decontamination are in place) or disposable.
The summary of methods of sterilizing face shield or goggles is shown in [Table 1].,
|Table 1: Summary of methods used for sterilizing face shield and goggles|
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| Medical Gowns|| |
Several types of protective gowns are available as part of PPE. These include aprons, surgical gowns, isolation gowns, and coveralls. Aprons cover only torso and they are used occasionally where limited contamination is anticipated. For protection during surgery and different clinical workplace, surgical or isolation gowns are preferred. A surgical gown is worn in order to protect both the patient and HCW from contamination. The parts of gown most likely to get contaminated are called critical zones. Front of the body from top of shoulders to knees and the arms from above elbow to the wrist cuff are the critical zones as these are most prone for receiving splashes during procedures. These parts of surgical gown are enforced with extra protection while other area is made of normal material. Isolation gown differs from surgical gown in level of protection offered as they have larger critical zones than traditional surgical gowns. All areas of the isolation gown except bindings, cuffs, and hems are considered critical zones of protection and must meet the highest liquid barrier protection level for which the gown is rated. All seams must have the same liquid barrier protection as the rest of the gown [Figure 8]. Isolation gowns are used when there is a medium to high risk of contamination. These gowns do not provide extended whole-body protection like possible openings in the back or neck and coverage up till the mid-calf only, as compared to coverall suits which provide 360° protection. Hazmat suits are also like coveralls [Figure 2]. Coveralls and gowns are deemed equally acceptable as there is a lack of comparative evidence to show whether one is more effective than the other in reducing transmission to health workers.
|Figure 8: Surgical gown (left) gives extra protection to front and sleevesonly whereas isolation gown (right) gives 100% protection (Red unprotected area C and D, green protected A, B, E and F)|
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Surgical and isolation gowns are evaluated for the resistance they provide against synthetic blood, aerosols, virus, and bacteria. ISO/FDIS grading are given based on the performance of the material. Isolation gowns and surgical gowns are regulated by the FDA as a Class II medical device that requires a 510(k) premarket notification. The Government of India requires that all gowns should have following information printed by manufacturer like Name of Manufacturer, SITRA/DRDE Unique Certification Code, and Test standard Date of manufacturing/Batch number. For ISO/FDIS 16603, class 3 is the minimum requirement for COVID 19 isolation ward.
Extended use means using a gown without removing, when providing care of a cohort of patients with COVID-19. This may increase risk of contamination with COVID-19 virus and may increase the risk of transmission of other pathogens between patients. Extended use, reprocessing, or use of alternative gown can be considered to meet the requirement of shortage of gowns at the time of ongoing corona pandemic. These measures should be considered temporary and should be avoided as much as possible when caring for severe or critically ill COVID-19 patients. These alternatives should also be avoided when performing aerosol-generating procedures and constant contact for more than 30 min in same environment or close contact (within 1 meter) for more than 15 min. Gown should be removed whenever it becomes wet, soiled, or damaged or exposed to splash of chemicals, infectious substances, or body fluids.
Cotton reusable gown
Cotton reusable gown is not impermeable to fluid hence does not provide adequate protection. If due to circumstances cotton reusable gown is used, it should be combined with barrier polyester sheeting which is worn above gown, with a property of water-repellent chemical finish. Main side effect is thermal comfort as these are nonbreathable and it does not provide protection of arms and the back of the torso, which can be exposed to splashes. Washing by machine with warm water (60°C–90°C) and laundry detergent is recommended for reprocessing of the gown. If machine washing is not possible, linen can be soaked in hot water and soap in a large drum, using a stick to stir, avoiding splashing. Then, soak linen in 0.05% chlorine (hypochlorite solution) for approximately 30 min. Finally, rinse with clean water and let it dry fully in the sunlight.
| Gloves|| |
Disposable gloves used by HCW are called medical gloves. Medical gloves are mainly two types. Examination gloves are simple inexpensive gloves, which may or may not be sterile and surgical gloves which have to be sterile. These gloves are regulated as Class I medical devices by the FDA. Strength, resistance to tear and leak, thickness and elasticity and biocompatibility are some of the criteria used for performance review by FDA.
Medical gloves can also be classified based on the material used. Latex is used most commonly for these gloves but latex is known to or trigger allergies, and it does not provide protection against organic solvents or chemicals. Nitrile is another material used for gloves which offers advantages over latex as it prevents latex allergies and tears are easily visible in these gloves. Nitrile also provides protection against chemical reagents. Besides latex and nitrile, many other products such as poly vinyl chloride, polyvinyl alcohol, neoprene, nor foil are used in making gloves but for medical purpose latex and nitrile gloves are used most commonly.
Medical gloves help in reducing the risk of contamination with blood and other body fluids and they reduce the risk of dissemination of pathogens to the environment. As a contact precaution during the time of ongoing corona pandemic, they are integral part of PPE. Under normal circumstances gloves should be used during all activities dealing with patient care which may involve exposure to body fluid or blood. Gloves should also be worn during any activity involving contact with nonintact skin or mucous membrane.
Selecting correct size of gloves is also important as too small gloves are likely to get ripped and are uncomfortable while too big may not provide protection because of inadequate seal. FDA has banned all powdered gloves intended for medical use in the USA since 2016. The WHO recommends use of nonpowdered gloves to avoid reaction with the alcohol-based hand sanitizer used during hand hygiene. Medical gloves should not be reused as they are single-use items and there are no recommendations regarding glove decontamination and reprocessing. At present, there is no validated, standardized practical procedure for safe reprocessing of glove although it is common practice in low resource many setting.
| Donning and Doffing Ppe|| |
All HCWs need to be taught the correct sequence of wearing (Donning) and taking off (Doffing) the PPE to avoid contamination. While wearing PPE, it is very important that the person wearing it is familiar with correct technique of donning and doffing of these equipment including mask or respirators. Individuals are instructed first to perform hand hygiene and then sequence is first gown followed by surgical mask, eye protection, and gloves in the end. The order of doffing is gloves first followed by gown, eye protection and surgical mask in the end [Table 2]. N95 is a tight-fitting respirator, it is not effective when it is not properly fitted, it needs to create a tight seal. Seal test is performed by inhaling after respirator is worn. If seal is good it should get puckered in slightly. It should be done every time a respirator is worn. Practical tips to remember while donning and doffing PPE are shown in [Table 3].
|Table 2: Suggested sequence of donning and doffing personal protective equipment|
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|Table 3: Practical tips to remember when donning and doffing off mask, respirator, and face shields (based on center for disease control guidelines)|
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Optimized use of personal protective equipment
There is acute shortage of PPEs as current corona pandemic has overwhelmed the capacity of health-care system globally. This crisis has forced the world to innovate ways to overcome this scarcity. In a recent publication, many options have been considered like reusing or extended use of masks and respirators or even some desperate looking measure like using plastic garbage bags as gowns and cutting out plastic water bottle for eye protection. Reusing the PPE after disinfecting by various means such as Heat, EtO, hydrogen peroxide, UV, ozone, and hypochlorous acid are being considered as emergency measure. Other innovative option is to get fabric masks and gowns sewn locally. Even use of coffee filter masks or home HVAC filter masks have also been suggested. [Table 4] summarizes strategies to optimize PPE and equipment during pandemic.
|Table 4: Strategies to optimize personal protective equipment and equipment during pandemic (56)|
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Compliance issues with personal protective equipment
Since wearing these devices for long time is not very comfortable and breathing through them is difficult, it is possible that compliance may not be optimal among persons wearing it. Compliance for wearing gloves is high while compliance for wearing eye protection was lowest in one questionnaire-based survey. In another cross-sectional survey involving 16 facilities availability of PPE, a safety culture of unit, training of HCW were found to be determinant of improving compliance issues among HCWs Employers are required to train each employee who must use PPE. Everyone working in a health care facility must be trained to know about situations when PPE is necessary and also what kind PPE is necessary. They should be taught about how to properly put on, take off, adjust, and wear the PPE. They should be aware of limitations of the PPE. Moreover, they should also know about proper disposal of PPE. Checklist for PPE kits required for medical professionals and support staff treating the COVID-19 patients has been prepared on the basis of guidelines issued by MOHFW and WHO Guidelines.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4]