Technical field The present invention relates to a surgical airway mask for use by a patient during a surgical procedure.

Background When healthcare professionals, such as surgeons, operate on patients, steps are taken to ensure that the healthcare professionals do not infect or otherwise adversely affect the patient’s health and wellbeing. Every healthcare professional in an operating theatre, including the surgeon, must follow strict hygiene protocols, and all apparatus used during the operation (e.g. surgery) must be sterilised and properly pre-packaged. However, little consideration has been given to ways in which a patient might adversely affect the health and wellbeing of the healthcare professionals themselves.

With the advent of COVID-19 (referred to herein as Coronavirus, virus, Cov-19 or SARS-CoV-2 the virus which causes COVID-19), the spread of airborne contaminants has become a matter of concern for the general public and healthcare professionals. According to the World Health Organisation (WHO), as of October 2020, among 36,002,827 confirmed cases of COVID-19, the SARS-CoV-2 virus has caused 1 ,048,781 deaths. Among 91 ,212 confirmed COVID-19 patients in China, 81% had mild symptoms, nearly 14% develop severe symptoms such as dyspnoea and hypoxia, 5% became critically ill, and 1% to 3% required intubation. Among critically ill patients, the virus caused acute respiratory distress syndrome in almost 67% of patients, with 71% of all patients requiring mechanical ventilation with a 28-day mortality of 61 .5%. Overall case fatality rate ranges between 2.3% and 7.2% between countries.

The precise mechanism of COVID-19 transmission is still unclear; however, it is becoming increasingly evident that inhalation of aerosols with virus particles is an important route of transmission. While the SARS-CoV-2 virus spreads primarily by droplet and contact contamination, aerosolised infectious droplet nuclei (<5- microns in diameter) can float in the air for several hours and can remain active on surfaces for >3-hours.

An aerosol generating procedure performed in an operating theatre on a patient with an infectious disease such as COVID-19 puts healthcare professionals at risk. High titres of SARS-CoV-2 are found in the upper aerodigestive tract (nose, sinuses, nasopharynx, mouth, oropharynx, and larynx) with the highest concentration of the virus found in pulmonary secretions from the trachea and bronchi, followed by mucous and saliva of infected individuals. Clinical and endoscopic examinations of the upper aerodigestive tract are among the most common diagnostic head and neck procedures and are routinely performed by a wide variety of healthcare professionals and are associated with significant exposure to mucous, saliva and pulmonary secretions. Otolaryngology Head and Neck Surgeons (OHNS) are at particularly high risk of SARS-CoV-2 exposure and infection due to their proximity and contact with oropharyngeal structures and the use of surgical tools such as high-speed surgical drills, ultrasonic scalers, and air- water syringes. Among common OHNS procedures, endolaryngeal surgery, functional endoscopic sinus surgery, and skull base surgeries are aerosol generating procedures with a high risk of infection to healthcare professionals.

Orotracheal intubation is one of the highest risk aerosol generating procedures performed by Anaesthetists due to direct exposure to the airway during induction and is of particular concern to frontline anaesthetic, emergency and intensive care teams. Other airway establishment procedures including nasotracheal intubation by laryngoscopy or fibre-optic guide also have high risks of contamination. There is similarly high risk of aerosol contamination during tracheostomy due to high positive pressures involved during ventilation and changing the tracheostomy tube. Other aerosol generating procedures, including non-invasive ventilation (NIV), high flow nasal cannula Oxygen (HFNO), mask ventilation, nebulisation, tracheal extubation, bronchoscopy and tracheal suction, also present a significant risk of infection to the Anaesthetist.

In addition to these aerosol generating procedures, there are reflex-induced events such as gagging and coughing that can occur without warning during a procedure on a patient that can also generate aerosols. Activation of these protective reflexes is not uncommon and can be induced by a variety of airway procedures.

The first reported physician deaths during the 2003 SARS-CoV-1 outbreak in Hong Kong and again during the 2019 SARS-CoV-2 outbreak in Wuhan were both Otolaryngologists. To date, the 2 otolaryngologists in the UK to have become and die from COVID-19 contracted the virus from local patients, and at least 20 OHNS in Iran have been admitted to hospital with COVID-19. Consequently, many additional healthcare workers have been quarantined due to close contact with the infected Otolaryngologists. Many similar incidents have been reported in Europe.

Without rapid diagnostic testing or an effective vaccine against SARS-CoV-2, all patients who present for care must be considered positive for SARS-CoV-2. To mitigate the impact of aerosol generation on their health, healthcare professionals use personal protective equipment (PPE) including surgical masks before, during and after surgical procedures. However, aerosols can pass through the pores of a standard surgical mask, therefore, many surgical procedures require the use of N95 filtered mask protection or a powered air purifying respirator (PAPR). The risk of infection from an aerosol generating procedure is even greater with prolonged exposure and poor infection control compliance.

Accordingly, there exists a need for products that minimise the spread of aerosols from a patient in an attempt to better protect our healthcare professionals, particularly those participating in aerosol generating procedures. The present invention seeks to overcome or at least ameliorate at least some of the problems of the prior art, or at least to provide a useful alternative.

Summary of invention

In a first aspect there is provided a single use surgical airway mask for use by a patient during a surgical procedure performed on the patient, the mask comprising a rigid outer shield configured to cover at least the patients mouth and nose; a sealing rim around the periphery of the rigid outer shield, wherein the sealing rim provides an airtight seal with the patient’s face; a plurality of self-sealing openings formed in the rigid outer shield wherein each self-sealing opening can be penetrated by a surgical instrument in use.

In embodiments, the mask is a single-use surgical device configured to cover and seal a patient’s mouth and nose. A rigid outer shield and sealing rim forms an airtight seal against the patient’s face. Appropriately sized self-sealing openings on the nasal portion of the SAM accommodate surgical instruments without compromising the seal.

In use, a self-sealing opening in the surgical airway mask can be cut open by a surgical instrument. The opening can then seal around the outside surface of the surgical instrument once it has penetrated though the perforation. Perforations can be pre-cut e.g. halfway through the material forming the self-sealing openings. These perforations can act as a cutting guide for the surgeon to cut, while maintain bacteria protection, when not in use. The self-sealing openings can be partially perforated to maintain the integrity of the mask and to provide a cutting guide for surgeons for when the mask is required. A sharp instrument can be used to complete the perforations to accommodate the surgical instruments. The surgeon has the flexibility to keep unused perforations intact if they are not needed, maintaining the integrity of the seal. In a procedure that requires access to only one part of the patient’s face, the surgeon might only cut into one of the self-sealing openings while the others remain intact. Once the instrument is inserted into the opening, the contact surface between the opening and the surgical instruments remains substantially airtight.

The surgical airway mask can be referred to as a Surgical Aerosol Minimiser (SAM) device. Throughout, references to surgical airway mask could be replaced by the term SAM unless the context makes clear otherwise. In embodiments, the mask can allow for endotracheal intubation, oxygenation, ventilation, and anaesthesia, as well as for the passage of surgical instruments though self-sealing openings.

Healthcare professionals wear PPE (including masks) to prevent (or reduce) the transfer of aerosols generated by the patient. The present invention takes the prevention of transfer one step further by isolating the aerosol within the airtight space around the nose and mouth of the patient thereby in embodiments providing an additional barrier of protection for surgical staff. The surgical airway mask fitted to the patient creates a barrier over the area from which a patient can emit aerosols and in principle contains any generated aerosols within the mask which can then be disposed of following use.

The mask according to embodiments of the present invention can provide effective protection against potentially infectious aerosols by their containment at the site of formation in conjunction with the use of existing respiratory PPE (gloves, waterproof gown, eye protection, fit-tested N95 respirator, or powered air purifying respirator - PAPR) in accordance with international and local guidelines

The surgical mask offers the ability to perform surgery through the mask. The mask can be fitted to the patient either before or after the patient is anesthetised. Once in place, the surgeon can use a sharp surgical instrument such as a scalpel or other cutting device to penetrate the self-sealing perforated openings. The surgical instrument passes through the perforations (extended towards the patient) and the operation is performed through the mask. The self-sealing pre-perforated opening seals against the sides of the surgical instrument, creating an air-tight barrier. Once the surgical instrument is removed, the perforated opening self-seals or re-seals, maintaining the barrier integrity.

Each self-sealing perforation can be formed from a softer material than the rigid outer shield. This means that the surgical instrument can readily penetrate the perforations and pass through the mask towards the patient. It may be possible under the application of force for the surgical instrument to penetrate the rigid outer shield, however this is not the intended use of the mask.

By single use it is meant that the mask is intended to be used once and then discarded. It is important to dispose of medical waste according to official guidelines particularly if the patient is an infection risk. It should be understood that the mask could be used more than once following cleaning and sterilising, but this would be under unusual emergency circumstances where there is no availability of a new and unused mask. The mask is not intended for multiple uses not only because of the infection risk, but also because at least some of the self-sealing openings would have been cut in the earlier procedure. The mask is intended to be provided with all the self-sealing openings sealed and closed. The healthcare professional can cut into the self-sealing openings as and when is required during use. It is possible that not all the self-sealing openings will be cut open during a procedure. For example, in a procedure that requires access to only one part of the patient’s face, the surgeon might only cut into one of the self-sealing openings while the others remain intact.

The patient can be a human patient. Whilst all humans are different according to their age and ethnicity, typically, the nose and mouth of a human patient have little important variation. Accordingly, the masks can be provided in a variety of sizes to accommodate the nose and mouth and the healthcare professional can select the appropriate size prior to the surgical procedure.

The mask can be applied to the patient in anticipation of a surgical procedure. The mask can be applied to the patient before they are anesthetised. An advantage of the mask being in place before an operation is that if an emergency procedure is required, the mask is ready in place and can provide the intended barrier. Alternatively, the mask can be applied once the patient is anesthetised. An advantage of the mask being placed over the mouth and nose once the patient is unconscious is that they are unaware of the mask. This can be convenient for nervous patients or young children.

The surgical procedure can be an aerosol generating procedure. The aerosol generating procedure can be one in which a surgical instrument is passed into the nasal or oral passages of the patient. The procedure can be for example orotracheal intubation, nasotracheal intubation, tracheostomy, non-invasive ventilation (NIV), high flow nasal cannula Oxygen (HFNO), mask ventilation, nebulisation, tracheal extubation, bronchoscopy and or tracheal suctioning. The mask can also be used with for other surgical disciplines, particularly where the surgical approach is through the nasal pathways. Examples include eye surgeries and neuro-surgeries. The aerosol generating procedure can be one in which a surgical instrument enters into the anatomy of the patient under the mask. The procedure can be for example endolaryngeal surgery, functional endoscopic sinus surgery, and skull base surgeries like neuro-ophthalmology. In essence, the procedures can be anything to do with eyes and vision, neurologic or brain disorders, circulatory disorders and inflammation, trauma and/or tumours of the eye socket (orbit) or face, head, or brain.

The mask can be adapted to allow a variety of surgical tools to pass through its self-sealing openings including diagnostic and exploratory tools as well as guiding instruments. These tools can include those not intended to dissect the patient. The non-cutting surgical instruments can be those that enter the oral or nasal cavities of the patient. The non-cutting tools can be tracheal tubes, ultrasonic scalers and or air-water syringes and most commonly the endoscope.

The surgical instruments that can be used with the mask can include those intended to dissect or aid dissection. Surgical instruments can be for example, a scalpel, surgical drills, nasal scissors, side biters, arthroscopes and cystoscopes and bipolar cutting scissors.

The commonest diameter for surgical instrument such as laparoscopic instruments is 5mm. The narrower diameter (less than 5mm) instruments have less shaft rigidity and therefore are more flexible and more fragile than the larger versions. Most laparoscopic instruments offer only four degrees of freedom of movement: in/out, up/down, left/right and rotation. In addition, articulating / roticulating instruments offer angulation at their proximal ends, which can be particularly useful in achieving triangulation while performing single-incision laparoscopy.

The rigid outer shield of the mask can be formed from a thermoplastic elastomer (TPE). The masterbatch of material used to produce the mask could include a coloured material to impact a colour to the shield. However, desirably, the mask is transparent to give the healthcare professional and or surgeon the best possible view of the patient’s anatomy under the mask. If the mask is not transparent, the surgeon can look at an endoscopic screen during dissection.

In embodiments, in order to further improve the mask, the rigid outer shield can incorporate an antibacterial or antifungal agent. The antibacterial or antifungal agent can be in the material used to form the rigid outer shield and or it can be coated on the surfaces thereof.

The rigid outer shield can be formed by injection moulding. The rigid outer shield can have some flexibility, but typically maintains its shape under applied pressure.

It would not be desirable for the rigid outer shield to buckle or move during surgery when a surgical instrument is penetrated though one of the self-sealing openings.

The rigid outer shield can have markers or indications on it to assist the healthcare professional. The mask could have indications relating to its size, origins of manufacture and product code.

The rigid outer shield can be configured to have attachment points for straps. The straps can be used to secure the mask to the patient to ensure or at least reduce the likelihood that the mask will move once in place.

The mask can have any domed shape that raises it off the patient’s face. The mask can be at least about 1, 2, 3 or 4 cm in elevation from the patient’s mouth. In use, the rigid outer shield of the mask preferably does not contact the patient’s nose or mouth. It is important that the mask allows the patient to breath while in place.

The flexibility of the mask can allow it to conform to the shape of the human face. The mask covers at least the patient’s mouth and nose. The mask can be configured to cover the nose and mouth and other parts of the patient’s face. However, since it is only the nose and mouth that produce the aerosols that spreads contamination, the mask need only cover the mouth and nose.

The mask can have a bubble to accommodate the nose. The mask can have a bubble to accommodate the mouth. The mask can narrow at the part that extends towards the eyes so that the patient’s eyes are not covered by the mask and they are able to open and close their eyes and rest them comfortably while the mask is in place.

The mask can be off-the shelf in shape, or the mask can be manufactured specifically for the intended patient. A mask that is manufactured for a specific patient can provide additional comfort. Making a mask for a specific patient can involve modelling the contours of their face using a mould. Making a mask for a specific patient can involve modelling the contours of their face using a software package and then 3D printing or otherwise manufacturing the mask according to their shape.

The shape of the mask can be configured to create a seal against facial contours (cheek bones, nose, and mouth). To provide a seal, there can be a sealing rim around the outside edge of the rigid outer shield. The sealing rim can be around a part of the periphery of the rigid outer shield. However, the sealing rim is preferably around the entire periphery of the rigid outer shield. By being around the entire periphery there is more certainty that the mask can reduce or prevent the leakage and seepage of fluids and airborne particles from the oral and nasal cavities of the patient.

The material of the sealing rim can be formed from a highly stretchable polymer which conforms to the patient’s face. The Table of Figure 9 shows the typical properties of materials that are suitable for use. The sealing rim can provide an airtight seal. By airtight it is meant that aerosol and potentially harmful bacteria do not substantially escape from the mask during surgical use. Air leakage around intubation tubes into the sinus cavity occasionally occurs in the operating theatre. This may affect the integrity of the seal, therefore the mask can have an optional pre-perforated opening to transfer air through the mask to a cleaning station. The air filtration will vary from hospital to hospital; however, standards must be maintained. Air filtration guidelines for operating rooms are determined by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) using a standard known as Minimum Efficiency Reporting Value (MERV). MERV is determined based on the size of particles successfully removed from the air and is used to classify the efficiency of HEPA filters. Ratings range from 1-16 and efficiency increases as the rating increases. ASHRAE groups surgeries into three categories: minor surgical procedures (A); minor or major surgical procedures performed with minor sedation (B); and major surgical procedures performed with general anaesthesia or regional block anaesthesia (C). Each surgical category is given a minimum MERV rating it must comply with

The self-sealing openings are formed from a soft material such as a thermoplastic elastomer. The elastomer can be an elastomeric polyurethane. The elastomer can have high tensile and tear strength. The elastomer can have abrasion resistance. The elastomer can have a shore hardness of 40 to 55 yet withstand 25% total joint movement. The elastomer can be organic solvent, vegetable oil based and recyclable and medical grade approved.

In an embodiment, the rigid outer shield and the self-sealing openings are made from the same or similar elastomer, but the thickness of the elastomer differs. The rigid outer shield can have a thickness of at least about 1 , 1 .5 or 2 mm. The thickness of the self-sealing openings can be at last about 0.015, 0.025, 0.035mm. Thus, in an embodiment, the self-sealing openings are portions of the rigid shield that are at least about 50, 60 or 70 times thinner than the rigid shield. To be useful in forming the openings, the material should stretch easily to at least about 200% and have a break point greater than 500%. The material must have very good tear strength around 20.0kN/m and a Softness / Hardness around 30% to 40% Shore A. Furthermore, it must be capable of injection moulding for mass production. In an embodiment, the elastomer is a unique two-part, non-sag, tamper resistant elastomeric polyurethane joint sealant. The material of the openings is cuttable but retains at least some structural integrity so that the cut does not tear and provide a wide opening through which aerosol could be released. To assist in not tearing, the self-sealing openings are pre perforated. The pre-perforation can require a small amount of force for the tool to penetrate the opening. Once the pre-perforated slots have been penetrated by a surgical instrument the sides of the pre-perforated slots will create an air-tight barrier to all surgical instruments with an instrument under 10mm in diameter.

Upon removal of the surgical instruments, the pre-perforated slots will instantly close to an almost perfect seal, retaining and airborne harmful bacteria, within the mask.

The rigid outer shield material in the region of the pre-perforated self-sealing openings can have a thickened annular ring, supporting a thinner central region containing the radial perforations. This design feature, looks like an O-Ring” around the pre-perforated openings and prevents tearing of the pre-perforated slots past the O-Ring” inner circumference. Using TPE as a material of choice will allow for expansion of the pre-perforated slots while the O-Ring prevents tearing which aids to retaining bacteria.

In the rigid shield, the nasally located bubble can provide access for surgical instruments. The access can be via pre-perforated self-sealing openings. The pre perforated self-sealing openings in the outer shell of the mask allow for the passage of surgical instruments.

There can be any number of self-sealing openings in the nasal bubble of the shell such 1 , 2, 3, 4, 5, 6 ,7, 8, 9 or 10. There is an upper limit to the number of self sealing openings simply due to the available surface area in the outer shield. In a preferred embodiment there are 6 self-sealing openings with 3 self-sealing openings on the left side of the mask and 3 self-sealing openings on the right side of the mask. It has been found that 6 self-sealing openings positioned in various locations about the shield provides sufficient access for the healthcare professional to undertake the surgical/medical procedure. The 6 openings can comprise at least 2 opening for each side on the sinus, for dissections. There can be 1 opening and 1 exit for venting the mask if needed. The venting may be required since sometimes there is leakage from incubation, which could cause a build-up of gases in the mask. The 6 openings can all be the same size.

The self-sealing openings can be formed in the rigid outer shell to have any shape. In an embodiment, the self-sealing openings can each be round. Each self-sealing opening can be at most about 8, 10, 12 mm in diameter at its widest point.

Typically, surgical instruments have a 5mm external diameter shaft and the material forming the self-sealing opening is sufficiently flexible not to restrict the movement of surgical tools by having the capacity to stretch to provide up to a 10mm diameter hole. In some embodiments, rather than being small round or other discrete shaped self-sealing openings, the openings can be formed as channels of soft material that can provide for greater flexibility in where the self-sealing opening in the mask is created by the surgeons cutting tool. However, it is preferred that the self-sealing openings are small in overall size so that there is a reduced risk of tearing once the opening is perforated.

In the rigid shield, the orally located bubble provides access for ventilation tubes such as intubation and breathing tubes. The self-sealing openings for the ventilation tubes can be the same size as the other openings. The self-sealing openings for the ventilation tubes can be different from the other openings. The self-sealing openings for the ventilation tubes can be larger the other openings. A bigger opening at the base of the mask can be to accommodate an incubation tube. An anaesthetist will place an intubation tube inside the trachea of the patient, prior to surgery. The tube should seal the throat from gases escaping and there should be no air flow in the sinus, however, often the incubation tube leaks and gases flow into the sinus. The large opening can be slightly smaller than an incubation tube diameter. The mask will self-seal over the incubation tube once penetrated.

In embodiments, the SAM provides unrestricted movement for anaesthetists in their process of intubation and extubation.

The self-sealing perforations can be formed from a softer material than the rigid shield. By softer material it can be meant that the material is easier to penetrate with a surgical instrument. By softer material it can be meant that the material is thinner than the material of the rigid shield.

Currently, there are no effective and or efficient products in the consumable medical device market space that aim to mitigate the infection risk to healthcare professionals posed by aerosol generating procedures by providing a physical barrier at the source of aerosol generation.

A rubber dental dam could be used to reduce aerosol generation. Rubber dental dams create a barrier within the oral cavity and have been shown to reduce the generation of droplets and aerosols mixed with patient saliva and/or blood within a 1 -meter diameter of the surgical field by 70%. While it can be beneficial to locate the rubber dam to cover the nose and reduce the transmission of infectious aerosols, there are no ports for surgical instrument access or for the passage of an endotracheal tube for patient oxygen delivery and anaesthesia, limiting the use of this device to dental procedures.

An aerosol box could be used to reduce aerosol generation. An aerosol box is a reusable acrylic barrier enclosure placed around the patient’s head. It may be used during necessary procedures such as tracheal intubation, mask ventilation, extubation and bronchoscopy. Using a simulated cough producing fluorescent droplets, it has been shown that the aerosol box device reduces the macroscopic contamination of both the laryngoscopist and their immediate surroundings but presents an impediment to mobility during emergency airway manoeuvrers. Furthermore, a recent study has showed that aerosol boxes may increase intubation time and therefore expose patients to the risk of hypoxia. In addition, they may cause damage to conventional personal protective equipment (PPE), placing the airway operator at risk of infection. Finally, while having a reusable barrier saves on resources, it is difficult to fully disinfect and could potentially spread the virus between patients.

In an embodiment, just prior to surgery, the surgeon will place the mask on the patient and make sure that they are prepped for the procedure. When the surgeon is ready to start the procedure, the cutting tool will be moved towards the mask and one of the self-sealing pre-perforated openings will be perforated. The surgical instrument will pass through the opening and the surgeon will start the procedure. If during the procedure, the surgeon feels it is necessary to vent the mask, another of the openings can be cut and will reseal once the gas has vented. Once the procedure is complete, the surgeon can withdraw his instrument and the mask will seal over. The patient can move to after care with the mask in place. When it is appropriate, the mask can be removed and destroyed.

Brief Description of the Figures

Embodiments of the invention will now be described with reference to the accompanying drawings which are not necessarily drawn to scale, where some numbering is shown only on some Figures for clarity and which are exemplary only and in which:

Figure 1 is a top bird’s eye view of a surgical airway mask according to one embodiment of the present invention.

Figure 2 is an underside view of the surgical airway mask of Figure 1 .

Figure 3 is an end view of the lower/bottom of the surgical airway mask of Figure 1 .

Figure 4 is an end view of the upper/top of the surgical airway mask of Figure 1 .

Figure 5 is a side view of the of the surgical airway mask of Figure 1 .

Figure 6 shows the mask in place on a patient.

Figure 7 shows the mask in place during surgery.

Figure 8 shows the mask once penetrated by a surgical instrument.

Figure 9 is a table showing the typical properties of materials that can be used in the surgical airways mask. Detailed Description of Embodiments of the Invention

In the Figures 1 to 8 there is shown a surgical airway mask 10 for use by a patient 12 during a surgical procedure performed on the patient 12. The mask 10 comprises a rigid outer shield 14 configured to cover at least the patients 12 mouth 12b and nose 12a. A sealing rim 16 around the periphery of the rigid outer shield 14, wherein the sealing rim 16 provides an airtight seal with the patient’s 12 face. A plurality of self-sealing openings 18 formed in the rigid outer shield 14. In some Figures, not all the openings 18 are labelled for clarity. In this embodiment, each self-sealing perforation 18 is formed from the same material as the shield 14, only the material is thinner than in the rigid outer shield. In use, each self-sealing opening 18 can be penetrated by a surgical instrument 20. The openings can be pre-cut with perforations 19 to assist in causing them to open under force. The perforations can be seen in e.g. Figure 2 where 3 short cuts in a star shape are provided. It should be understood that any pattern of pre-cut perforation could be provided.

The surgical airway mask 10 offers the ability to perform surgery through the mask as shown in Figures 7 and 8. The surgical procedure shown in Figure 7 or Figure 8 can be an aerosol generating procedure. The aerosol generating procedure can be one in which a surgical instrument 20 is passed into the nasal or oral passages of the patient 12. In the embodiment shown, a surgical instrument 20 is in the nasal cavity. In Figure 8, a tube 20’ is in the oral cavity.

The mask 10 can be fitted to the patient 12 as shown in figure 6. The mask 10 can be fitted before or after the patient 12 is anesthetised. Once in place, the surgeon can use his surgical instrument 20 such as a scalpel or other cutting device to penetrate the self-sealing openings 18. The surgical instrument 20 passes through the perforated 19 opening 18 as shown in e.g. Figure 7 or 8 and is extended towards the patient 12 and the operation is performed on them through the mask 10. The self-sealing pre-perforated opening 18 seals 30 against the sides of the surgical instrument 20 as can be seen in e.g. Figure 7 or 8, creating an air-tight barrier. Once the surgical instrument 20 is removed, the perforated opening 18 self-seals, maintaining the barrier integrity against potentially infectious aerosols. The rigid outer shield 14 of the mask 10 can be formed from a thermoplastic elastomer (TPE). In the embodiment shown, the mask 10 is transparent, although the surgeon can look at an endoscopic screen (not shown) during surgical dissection. The rigid outer shield 14 maintains its shape under applied pressure.

For example, as shown in side view in Figure 5, if the mask 10 is compressed with force in the direction of the arrow shown, the shield 14 will press inwardly towards the patients face 12, but it should then spring back to retain its original shape. However, the outer shield 14 does not substantially deform during surgery when a surgical instrument 20 is penetrated though one of the self-sealing openings 18.

The rigid outer shield can be configured to have attachment points 26 for straps 28. The straps 28 can be used to secure the mask 10 to the patient 12 to ensure or at least reduce the likelihood that the mask 10 will move once in place. As can be seen in e.g. Figure 6, the mask is at least about 3 cm in elevation from the patient’s 12 mouth.

The mask 10 can have a bubble 14a to accommodate the nose. The mask can have a bubble 14b to accommodate the mouth. The mask 10 can narrow at the part shown in Figure 1 as A that extends towards the eyes so that the patient’s eyes are not covered by the mask 10 and they are able to open and close their eyes and rest them comfortably while the mask 10 is in place.

The shape of the mask 10 is configured to create a seal against the patient’s 12 facial contours (cheek bones, nose and mouth). In order to provide a seal, there is a sealing rim 16 around the outside edge of the rigid outer shield 14. This can be seen most clearly in Figure 2. The sealing rim 16 formed from a highly stretchable polymer is shown around the entire periphery of the rigid outer shield 14. By being around the entire periphery there is more certainty that the mask can reduce or prevent the leakage and seepage of fluids and airborne particles from the oral and nasal cavities of the patient 12.

The self-sealing openings 18 are formed from an elastomeric polyurethane. The elastomer can have high tensile and tear strength. The elastomeric polyurethane is cuttable but retains at least some structural integrity so that the cut does not tear and provide a wide opening through which aerosol could be released. To assist in not tearing, the self-sealing openings are pre-perforated 19. The pre-perforation 19can require a small amount of force for the tool 20 to penetrate the opening.

Once the pre-perforated slots 18 have been penetrated by a surgical instrument 20 the sides of the pre-perforated slots will create an air-tight barrier around the surgical instrument. Upon removal of the surgical instruments 20, the pre perforated slots 18 will instantly close to an almost perfect seal 30, retaining and airborne harmful bacteria, within the mask 10.

The rigid outer shield material 14 in the region of the pre-perforated self-sealing openings 18 can have a thickened annular ring 21 (depicted in e.g. Figure 3), supporting a thinner central region containing the radial perforations 18.

In the rigid shield 14, the nasally located bubble 14a can provide access for surgical instruments 20. The access can be via pre-perforated self-sealing openings 18. The pre-perforated self-sealing openings 18 in the outer shell 14 of the mask 10 allows for the passage of surgical instruments 20. In the Figures, there are shown six round self-sealing openings 18 in the nasal bubble 14a of the shell 14. There are three self-sealing openings on the left side of the mask 10 and three self-sealing openings on the right side of the mask 10.

In the rigid shield 14, the orally located bubble 14b provides access for ventilation tubes such as intubation and breathing tubes. This can be seen most clearly in Figure 3 with opening 18 being shown in the lower bottom surface of the mask.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. Any promises made in the present description should be understood to relate to some embodiments of the invention and are not intended to be promises made about the invention as a whole. Where there are promises that are deemed to apply to all embodiments of the invention, the applicant/patentee reserves the right to later delete them from the description and does not rely on these promises for the acceptance or subsequent grant of a patent in any country.