In our living and work environment, we are often exposed to physical, chemical and biological harmful substances suspended in air or contained in droplets and aerosols. Workers of certain professions are exposed to harmful particulates. For example, healthcare workers are exposed to droplets and aerosols generated from the airway and oral cavity of patients. Cleaners and construction workers work in dusty environment. The concentrations of pollutants and dusts in the atmosphere can be heavy and enhanced by climacteric conditions such as gusts and airflow stagnation. Personal protective equipment (PPE) commonly consisting of caps, masks, eye and face shields, barrier clothes and gown is used with the purpose of isolating the body from such contaminants.

In the beginning of the outbreak of SARS, many healthcare workers became victims of this devastating disease mainly because of the ignorance of how it is transmitted. Soon the portals of entry (the respiratory tract and eyes) and the modes of transmission (via contact with droplets, aerosols and contaminated surfaces) were known. Although the disease is regarded preventable if the appropriate preventive measures are taken (such as hand washing, wearing of mask and eye protective devices) healthcare workers are still continuously being infected.

The ordinary protective devices healthcare workers are using leave parts of the face and neck uncovered, thus exposing them to contamination. After taking off these devices and in the erroneous belief that adequate protection has been provided, the harmful contaminants can actually be introduced into the portal of body entry – the eyes, nose and mouth, if the hands touch them after touching the contaminated parts of the face and neck. Improper handling of contaminated protective devices such as goggle and mask likewise can introduce contaminants into these portals of body entry. The mask and face shield are often applied incorrectly and shifted in position such that they cannot perform the function of effective barrier.

That the neck and part of the face remain uncovered despite all these endeavours for prevention contributes to this happening. Entire coverage of the head and neck is the only sure way of preventing contamination of the portal of entry – the eyes, nose and mouth, by aerosols, droplets and splashes. The SARSguard was developed based on this concept and belief and contributed to solving the problem of continuous infection of healthcare workers.

The existing head and neck isolation devices are sophisticated and incorporate powered ventilation systems. They could be quite heavy and putting on such devices requires prior training and is time-consuming relative to the critical time required of life-saving procedures.

Their multiple components and conduits increase the chances of defective production and malfunction. The possible leakage that could happen when the powerful air intake device is activated could make the devices hazardous since they may actively suck in contaminated air from the at-risk environment. The complicated degowning procedures, in particular if they are associated with zipping and stretching of elastics, could be hazardous because the contaminants are fluffed up into the air thus causing contamination of the user, the bystanders and the environment.

These products are meant for reuse, thus posing serious problems in proper and effective decontamination after use. The decontamination processes are certainly complicated, consume a lot of resources and total effectiveness is difficult to guarantee. These devices are very expensive and the complicated maintenance adds to the cost of their usage.

Fogging up of the eye piece with serious impairment of vision is a persistent problem with most personal protective devices that occlude the head and eye portion unless the device has incorporated a powered source of airflow through it.

The SARSguard is light so it does not tire the user from weight bearing. It can be applied in seconds; it does not involve cumbersome wearing procedures. Therefore, it is most suitable for emergency situations.

The SARSguard does not utilize powered air exchange device, thus removing the possible hazards of massive and active intake of contaiminated air associated with faulty equipment.

The SARSguard incorporates removal (degowning) procedures which do not cause contamination of the user and dissemination of the contaminants. This is an important consideration for any acceptable personal protective equipment (PPE) in the context of infection control.

The SARSguard is designed for single use thus avoiding all the problems of decontamination associated with reuse.

The SARSguard has solved the fogging problem that is common to all barrier devices that do not incorporate a powered source of airflow through its design features and the special procedures for fogging avoidance and defogging.

The SARSguard provides a simple, logical, efficient, effective and economical means of isolating the head and neck for the intended barrier functions. Because of the desired superior protection that it can offer to healthcare workers, the use of the SARSguard should be considered in at-risk situations and a part of the full personal protective equipment (PPE).


The SARSguard effectively isolate the head and neck where the main portals of body entry – the eye, nose and mouth, are located.

It offers a barrier for these structures against contact with direct head-on projections of non-pressurized droplets, aerosols and light splashes which may be generated in the clinical settings.

It also prevents the insidious and careless introduction of harmful substances from otherwise contaminated head and neck structures into the above portals of body entry.

It provides additional protection against contracting droplet- or aerosol-borne infection in conjunction with the use of standard personal protective equipment (PPE).


The SARSguard is indicated for use in situations where isolation of the head and neck is desirable for additional protection of the eye, nose and mouth against entry of harmful substances via direct head-on projections of contaminated droplets, aerosols and light splashes. It use should be considered an additional protection against droplet- or aerosol-borne infection (such as SARS) in conjunction with the use of the standard personal protective equipment (PPE).

Its use can also be considered a universal preventive measure for healthcare workers whose work involves exposure to patient’s airway at close distances.

The following conditions and procedures put the healthcare workers involved at risk of contamination by aerosols, droplets and splashes:

  • Intubation and extubation
  • Tracheostomy
  • Chest-tapping
  • Suctioning of sputum
  • Spoon-feeding of bed-ridden patients
  • Chest physiotherapy
  • Nebulizer application
  • Procedures that involve accidental or intentional puncture of blood vessels
  • Procedures that involve contact with patient’s airways at close distances
  • Sudden head-on coughing, sneezing and vomiting from patients
  • Consultation with patients having signs and symptoms of infectious diseases (e.g. influenza, common colds, pneumonia, SARS, TB)
  • All kinds of hard tissue drilling procedures
    • Orthopaedic surgery
    • Craniotomy
    • Some ENT procedures
    • Oral & Maxillofacial surgery
  • Most kinds (if not all) of dental procedures
    • All tooth-cutting procedures
      • Cavity preparation
      • Crown preparation
  • Ultrasonic tooth cleaning
  • Spraying of air-water mixture
  • Blow-drying with air
  • Procedures and conditions that induce severe projectile cough and vomiting reflexes
    • Intervention of the oral cavity and airway
    • Patients who have sensitive oro-pharyngeal reflexes

The following types of healthcare workers are particularly at risk of contracting potentially serious and fatal infections transmitted by aerosols and droplets (such as SARS):

  • Doctors, nurses and auxiliaries working under the at-risk conditions and environment
  • Doctors and nurses performing the at-risk procedures
  • ICU doctors and nurses
  • A & E doctors and nurses
  • Anaesthetists
  • Chest physicians
  • Orthopaedic surgeons
  • ENT surgeons
  • Dentists
  • Neurosurgeons
  • Physiotherapists

Instructions for use:      

  1. Apply the usual protective measures which consist of wearing of protective cap, mask and gown before wearing the SARSguardTM.
  2. Wear a hang-around-the-neck electric fan over the neck. Turn the fan on (low fan speed suffices). Angulate the two fan heads on the side up and direct them at your face.
  3. Put the SARSguard over the head so that the headband is positioned just above the eyebrows.
  4. Secure the headband by fastening the Velcro tape at the back.
  5. Fasten the post-auricular strap to ensure the vents stay close to the back of the head and behind the ears.
  6. Adjust the final position of the SARSguard so that the facial visor is in the vertical position.
  7. Tape down the mid portion and lower border of the neck and chest cover with the mounted adhesive tapes.
  8. After use, unfasten the back.
  9. Bend the head forward and by lifting the free ends of the headband, slide the SARSguard out without contaminating your head and neck. Dispose of the contaminated SARSguard properly.

SARSguard instruction 1-9 photo

Tips for Eyeglasses wearers:

  1. Tape the eyeglasses to the forehead in the middle to prevent them from shifting.
  2. Tape down the upper edge of the surgical mask to the bridge of the nose and face to block upward escape of exhaled air.

How to minimize fogging during use:

Wearing of the SARSguard for an extended duration may cause discomfort from increased warmth and humidity and fogging up the inside surface of the facial visor. To prevent all these from happening, you should wear a hang-around-the-neck electric fan and turn it on (low fan speed suffices) before putting on the SARSguard. The dangling fan heads on both sides should be angulated upward and directed at your face. In this way, you can have many hours (until the battery runs out) of comfortable and fog-free working condition. You can therefore focus and concentrate fully on performing your procedure without any distraction.


SARSguard is for single use only. It should only be used under environment which is well ventilated and does not contain fire risks. Do not use in flammable conditions or as protection against sparks or flame. Use only against direct light splashes of non-corrosive liquids or dust. It is non-impact resistant. Although there are vents on both sides in the post-auricular area to allow ventilation, some users of this device may experience difficulty in breathing when masks are being worn at the same time. The duration of use depends on the user’s tolerance level or how soon respiratory discomfort is encountered. In general, it is used for quick procedures only. For extended procedures, consider use of an electric fan inside or supplementary air or oxygen supply via nasal cannula or other delivery devices introduced from behind. If intended users are suffering from respiratory or cardiovascular diseases, medical advice should be sought before using this device. Keep this device out of reach of children. Improper wearing and failure to recognize the symptoms of respiratory distress associated with the use of this device may be hazardous to health. This device should not be used as a stand-alone device but must be used together with other PPE.

How the SARSguard works                  

The SARSguard is a hood-like structure that covers the entire head and neck down to the mid-chest in front and the shoulders on both sides and at the back.

It is constructed from a continuous sheet of non-woven polypropylene which has only three fenestrations – the facial window to accommodate the transparent facial visor and two post-auricular vents one on each side to allow exchanges of air.

The edges of the transparent facial visor and the non-woven polypropylenesheet form a water-proofing interface.

The PET transparent facial visor is impervious to water. The non-woven polypropylene sheet is water repellent, meaning resistant to penetration of light splashes.

Thus the structural materials and the seal of the interface make the SARSguard repellent to entry of aqueous aerosols, droplets and splashes generated and projected from the usual clinical procedures and situations. 

There is a generous space between the front of the SARSguard and the facial structures and the neck, providing additional barrier against contact with the projected contaminants.

The post-auricular vents are prevented from contact with head-on projections of ontaminated materials because they are situated behind the greatest circumference of the facial hemisphere. The operator has to put on the standard personal protective equipment (PPE) consisting of the protective cap, face mask and gown. In the unlikely event that fine aerosols float through these vents, they will be trapped by the protective cap that extends to the post-auricular area.

Demonstrations of barrier function 







Test of fluid repellent function: 

The forces and pressures that propel the aqueous aerosols, droplets and splashes generated in the usual clinical settings never have the magnitude of those that are power-generated.  Therefore, in the context of machinery generated pressures and forces, the propulsion of aerosols, droplets and splashes generated from clinical procedures and by patients is practically regarded non-pressurized. Thus, the test of the SARSguard for its water repellent function should be performed in the above context.

Test 1




The commonly asked questions:

  1. Can the SARSguard filter viruses?
    The SARSguard is intended to function as a fluid and coarse particle barrier. It is never intended to function as fine particle filter although the structure of non-woven polypropylene sheet does impart filtering ability to the material. According to the study of Kimberly-Clark which is one of the market leaders in the manufacturing of non-woven prolypropylene sheet, its polypropylene sheet  (marketed as “Spunguard”) has been tested to be effective in filtering dry particles of 4 to 5 microns in diameters.
  2. Since there are two vents at the back, would the protective function be compromised ?
    Again, we have to understand the intended functions, indications and conditions of use of the SARSguard. The SARSguard is not intended to function as a filter for fine air-borne particles. It functions as a barrier for eye, nose and mouth and the rest of the head and neck against direct head-on contact by patient’s droplets, aerosols and light splashes generated during operative procedures. Therefore, it is indicated for use in situations where the users are exposed to the hazard of direct, head-on projection of droplets, aerosols and light splashes in their clinical work environment. It should be considered an additional protective device in conjunction with the use of the standard PPE.
    Under the normal circumstances, the projected aerosols and droplets would not be able to manoeuver bends and corners. Since the vents are situated behind the greatest front hemisphere and is hidden in the post-auricular area, the likelihood of these aerosols and droplets entering them is very remote.
     In the very unlikely event that they went through the vents, they will be trapped by the protective cap that covers the ears and the post-auricular areas.
     Therefore, the travelling of aerosol-borne particles to the portals of body entry situated in the front part of the head is practically a theoretical risk only.
     If the user is still worrying about the entry of contaminants, the vents can be completely occluded with the rectangular polypropylene sheets provided.
     Occluding the vents will compromise ventilation. Therefore, supplementary oxygen (e.g. via nasal cannula) is recommended. The connecting oxygen tubing should enters and exit the Sarsguard through the back.


  1. Would it be difficult to breathe after wearing the SARSguard?
    The SARSguard does not incorporate powered device for air exchanges which are effected passively through the bilateral post-auricular vents. The common concern of the prospective users is that whether wearing of the SARSguard would be suffocating. While the majority of the users experienced no problem, some reported difficulties in breathing after wearing the SARSguard. This could have been caused by folding up of the vents. Therefore, the users should ascertain that the vents are not folded up after putting on the SARSguard. The users should have reasonable expectation of the performance of the SARSguard; it is not supposed to be worn for a long time without assisted ventilation. How soon respiratory discomfort develops depends on the ventilation condition of the environment, the physiological function, the tolerance and the exertion level of the users. If long-time wearing and strenuous work are anticipated, supplementary oxygen, (e.g. through nasal cannula) should be considered.
    The breathing discomfort is considered an inherent limitation of this device rather than a design fault in view of the deliberate omission of an active air exchange component. The purpose of inventing the SARSguard is to make available a piece of PPE that is simple, effective, efficient and economical without the need to spend a fortune on its purchase and maintenance. If complicated designs and accessories had been incorporated, the cost of production and the risks during use would have been very much increased. In the risk analysis, the breathing difficulty has been evaluated a low risk factor. It should not be used to invalidate the many benefits obtainable from this device. When a medical device is designed and evaluated, it should be done in the context of the Essential Requirements (Annex I) of the Medical Device Directive 93/42/EEC(MDD) that a medical device will not compromise the safety of patients and users and the risks are outweighed by benefits.
    The inventor routinely wears the SARSguard when performing minor operations in a standing position in a clinic environment. The durations of these operations range from 30 minutes to one-and-a-half hour. No breathing discomfort has been experienced.

Test of effects on respiratory function 

The following simple study was performed to test the respiratory function of the user after wearing the SARSguard.

The tested object wearing the standard PPE consisting of the protective cap, surgical mask and protective gown was seated and instructed to do clerical work. The baseline pulse rate and oxygen saturation were measured with the non-invasive pulse oximeter before putting on the SARSguard.

These parameters were measured every five minutes after wearing the SARSguard. The duration of the experiment lasted 60 minutes. After taking off the SARSguard, these parameters were measured again.

Five objects of normal health consisting of two male and three females were tested. The results showed there were no morbid changes in the pulse rate and oxygen saturation on wearing the SARSguard for one hour doing work requiring low energy consumption

Problem Solving Guide:

  • The fitting is too loose.
     > Tighten the headband.
  • The SARSguard shifts position during use.
     > Tighten the headband before use.
  • Eyeglasses fog up.
     > Warm up the eyeglasses in warm water and moisten the lenses with anti-fog.
     > Tape down the upper border of the face mask to prevent uprising of expired air.
     > Improve room ventilation.
  • The transparent facial visor fogs up.
     > Moisten the inner surface with anti-fog and leave it wet.
     > Move the magnetic wiper across the visor to clear fog.
     > Improve room ventilation.
  • I am still worried that the vents allow entry of contaminants.
     > Cover the vents with the rectangular polypropylene sheets provided.
     > Breath supplementary oxygen (e.g. via nasal cannula)
  • Breathing difficulty encountered.
     > Check that the vents are not folded up.
     > Improve room ventilation.
     > Shorten the duration of use.
     > Avoid unnecessary body movements to minimize oxygen consumption.
     > Breathe supplementary oxygen as above.

For further information or before use, please go to: