InVictoTM Ventilator - Q & A...InVictoTM Ventilator - Q & A For non-clinicians: What is InVictoTM?...

InVictoTM

InVictoTM and the InVictoTM Device are trademarks of JFD Limited. Patent Pending for the InVictoTM Ventilator system.

Copyright © JFD Limited 2020

For more information contact: [email protected]

InVictoTM Ventilator - Q & A

For non-clinicians:

What is InVictoTM?

It is a revolutionary respiratory ventilator that can be used to treat COVID-19 patients either in a hospital situation or in pre-clinical care.

What does InVictoTM do?

The ventilator uses an air or oxygen supply to provide breathing support for patients suffering from respiratory failure – including COVID-19 patients. Similar to conventional ventilators used in hospitals.

How is it different from conventional ventilators?

Conventional ventilators are complicated machines that use many different components and internal systems to deliver a range of breathing support treatments to patients. They are expensive and are in short supply everywhere.

InVictoTM costs around one tenth of a conventional ventilator. It is a small device that has no moving parts and operates simply from a gas supply without the need for electricity. It provides many of the important features that convention ventilators do and can be manufactured quickly and in large quantities to meet immediate global requirements.

How does InVictoTM work?

The ventilator connects between a regulated gas supply of either normal air, oxygen enriched air or pure oxygen and the patient. InVictoTM is supplied to the patient either via mask or intubation, via an endotracheal tube or tracheostomy tube.

The gas supply pressure is adjusted to set the amount of air in each breath (tidal volume) and the maximum pressure delivered to the patient.

The ventilator will automatically cycle between breathing in and out without any input from the patient. This is important for unconscious or heavily sedated patients who cannot breathe for themselves. If the patient is breathing, the ventilator automatically tracks the patient’s breathing to provide pressure support as required.

A pressure cycled automatic ventilator for COVID-19 patients

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Is it safe? Has it been qualified?

The ventilator is based on an original design that has been used safely in a clinical setting since the 1970s and was developed and qualified for medical oxygen treatment by a company that is now a part of the JFD group. This design has been used to treat many hospital patients but has been superseded over the years by more complex modern machines.

JFD have taken the original proven design principles and combined this with modern manufacturing and patient monitoring techniques to develop a revolutionary device – InVictoTM. It will provide a proven, safe, reliable answer to the global COVID-19 pandemic.

Who are JFD? I’ve never heard of them before…

JFD is a part of the James Fisher and Sons PLC and specialise in the design and manufacture of equipment for deep-sea saturation diving, military diving, submarine rescue systems and other underwater industries. As world leaders in life support breathing systems they have delivered equipment for many years for life-critical applications. Head-quartered in the UK, JFD employ over 700 people worldwide.

How can such a small, simple device replace conventional ventilators?

InVictoTM does not offer as many different adjustments and configurations as modern ventilators.

InVictoTM does however provide many of the features that conventional ventilators do and therefore is an ideal solution where there are insufficient ventilators to treat all patients.

It is a low cost, highly reliable and simple device suited to low resource areas where there is a lack of funding and / or clinical expertise.

Does InVictoTM provide patient monitoring and alarms?

It is vitally important for doctors to be able to monitor ventilated patients at all times. The InVictoTM ventilator comes with a sophisticated alarm and monitoring system that ensures that all critical parameters are continuously measured and displayed. Doctors can set alarms and the system can connect to a display / logging computer at the bedside and to a networked multi- patient monitoring computer, if required.

Will InVictoTM be used in the UK to treat COVID-19 patients?

JFD are actively working with the UK Government and medical experts across the country to become approved to supply hospitals and organisations with InVictoTM systems. JFD are ready to supply thousands of ventilator systems every week that can be used to beat the global Coronavirus pandemic.

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Explain how the InVictoTM ventilates the patient…

The ventilator device is a bi-stable gas routing oscillator / assister. When supplied with gas it will be in one of two modes; either inspiration or expiration. The gas flow direction to / from the patient’s lungs is routed by the ventilator automatically between these states. Transition between inspiration and expiration states occurs when a pre-set inspiration lung or ventilator output pressure is reached. Transition between expiration and inspiration occurs when the lung pressure reduces to equal the exhaust pressure.

What ventilator methods does InVictoTM provide?

InVictoTM provides both mandatory and patient-assisted / triggered breathing support. The transition between modes is completely automatic without intervention.

In mandatory ventilator operation where no patient trigger exists, the breathing cycle oscillates automatically between inspiration and expiration. The transition from inspiration to expiration occurs when the lung pressure reaches a threshold value which is set by the ventilator supply pressure. The transition from expiration to inspiration happens when the lung pressure drops to the ventilator exhaust pressure. The addition of a standard PEEP valve to the ventilator exhaust limb will lift the expiration to inspiration transition to the PEEP valve pressure.

If the patient is breathing, or attempts to breathe, when otherwise receiving mandatory ventilation, the ventilator detects the patient’s actions and responds automatically as follows:

If the ventilator is in the inspiration state, the lungs will be filling and pressure in the lungs will be increasing linearly. If the patient attempts to exhale, the lung pressure will immediately rise until it reaches the inspiration to expiration trigger pressure causing the ventilator to immediately switch to expiration mode. This occurs without the PIP exceeding the set value, but the expected VT will not have been achieved.

If the ventilator is in the expiration state, the lungs will be emptying naturally and pressure in the lungs will be decreasing exponentially (with a small negative pressure assist). If the patient attempts to inhale before the ventilator exhaust pressure is by the lung pressure, the action of inhaling will drop the lung pressure immediately to reach the exhaust pressure (or PEEP pressure). This is the expiration to inspiration trigger pressure, so this causes the ventilator to immediately switch to inspiration mode.

The ventilator is therefore tracking the patient’s breathing effort whichever direction that the patient triggers. The InVictoTM is therefore operating in Synchronously Intermittent Mandatory Ventilation Mode (SIMV).

In this mode, the pressure support (above PEEP) is the peak inspiratory pressure value set for the patient’s treatment and therefore the actual operating mode is SIMV + PS.

What is the PEEP range and method of adjustment?

PEEP is achieved using a standard medical PEEP valve (e.g. as would be used for CPAP treatment) connected to the exhaust limb (hose) that is in circuit after the ventilator exhaust and the room vent (or filter unit). PEEP values are set by the use of the correct pre-set PEEP valve or by setting an adjustable valve.

What safety features exist for protecting against overpressure to the patient?

The patient connection from the outlet of the ventilator is fitted with a standard overpressure relief valve. This is typically a 40cmH2O safety relief valve.

For clinicians, doctors and medical experts:

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How is the ventilator connected to the patient and is it attitude sensitive?

The ventilator is very small and therefore is normally positioned close to the patient in-line with the gas hoses. There are three gas connections to the ventilator that are all different sizes to avoid incorrect connection. The patient lung connection uses a standard universal 15mm ET Tube push-fitting. The gas inlet and exhaust connections also use standard push-fittings. Patients can be supine or prone with an extension tube between the ET tube or tracheostomy tube and the ventilator outlet being used. A 90° connector at the patient would normally be required.

What adjustments are available with the system?

Unlike conventional modern ventilators where all parameters are adjustable independently, the InVictoTM provides adjustment of only some parameters through the following methods:

The desired PEEP value is set by fitting the correct PEEP valve to the exhaust limb.

The FiO2 is controlled through the oxygen mixing / blending valve upstream of the ventilator supply hose. This is a simple (conventional) valve adjustment allowing a FiO2 in the range 21% (pure air) to 100% (pure O2) to be set. Adjustment is indicated on the mechanical gas flow-meter but actual FiO2 is monitored with a sensor and displayed.

Next, the supply pressure value is set using a manually adjustable pressure regulator. The ventilator operating inlet pressure range is between 35cmH2O and 200cmH2O. This adjustable pressure is directly proportional to PIP value in the range 5 to 35cmH2O. The setting of the supply pressure is unrelated to PEEP value so if a desired 25cmH2O PIP is set, the changing of a PEEP valve from (say) 5cmH2O to 10cmH2O will not affect PIP.

The tidal volume (VT) is not adjustable independently of PIP value, rather it is directly proportional to the adjustable PIP value, in the range 350mL to 850mL. This inability to set VT independently of PIP may be seen to be a disadvantage however these two values are normally closely linked in the specific ventilation requirements.

In order to assist the operator in understanding the correct ventilator supply pressure setting for a particular treatment, a laminated look-up table / chart is provided to illustrate the expected PIP and VT for different pressure values. The monitoring system also displays these parameters.

The fourth adjustable parameter is the minute volume of the ventilator. During the design and qualification process there were three different sizes of ventilator produced that varied in their characteristics to provide three different minute volumes for the same applied supply pressure. The clinician would firstly establish a desired minute volume based on the patient’s size and condition or through spirometry. The most appropriate ventilator size (small / medium / large) is then selected to ensure that the desired VT and PIP can be achieved across the input pressure range. Ventilators are colour coded and marked to avoid incorrect selection and these cover MV values up to 15 litres per minute.

Which parameters are not adjustable?

The inspired gas flowrate is constant for a given supply pressure value. The respiratory rate (RR) in breaths per minute is not independently adjustable but rather is a function of the supply pressure setting and PEEP valve setting. Respiratory rate is inversely proportional to supply pressure and through adjustment of supply pressure a RR can be set.

Inspiratory: expiratory time ratio is a constant for the ventilator design and a value of 1 : 1.5 is typical.

There is no facility to provide a plateau after PIP is reached.

Flow-rate controlled modes are not possible as the ventilator is a pressure-controlled device.

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What is the normal gas flow to the ventilator?

The nature of the ventilator design is such that there is always a gas flow required including during the expiration phase. Actual gas consumption is dependent on the set supply pressure but is typically a maximum of 20 litres / minute. The supply gas is also the breathing gas so therefore the oxygen consumption will be a function of the FiO2 setting.

What does the breathing cycle look like?

The inspiration phase is a straight line with positive gradient due to the constant flow characteristics of the ventilator. After the ventilator switches to the expiry phase the lung pressure drops in an exponential manner. The shape of the breathing profile (lung pressure vs time) is similar for different supply pressure settings, PEEP setting and the size of ventilator in use but the geometry / aspect ratio remains similar for all. An example of the profile shape for mandatory breathing is shown below:

How does the ventilator react to varying lung compliance?

As the InVictoTM is a pressure cycled assistor-controller ventilator with the switch point being set by the load pressure (lung pressure), the unit automatically adjusts VT with different lung compliances. The RR will vary with lung compliance.

The ventilator has been validated for lung compliances of 10, 20, 35 and 50 mL / cmH2O.

What medical / clinical references does the InVictoTM have?

The initial ventilator design was produced by Vickers Medical in the 1960s and the unit was developed during the 1970s and 1980s. The ventilator has been used for many years in hospitals across the globe for treating critically ill patients (e.g. trauma or burns patients) in a 100% O2 environment at hyperbaric pressures up to 3barA.

As the original ventilator was developed and qualified so many years ago, much of the qualification data and documented test reports are now lost and for this reason JFD have redesigned the interfaces and instrumentation for the system to allow modern monitoring techniques and numerical analysis to ensure key operational parameters are met.

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What monitoring and alarm processing is included with an InVictoTM system?

It is understood that all important parameters must be measured, displayed, logged and monitored for a range of conditions.As the ventilator is an inherently solid-state device with no electrical components or moving parts, an auxiliary monitoring system is needed to provide patient safety and visibility of operational parameters to clinicians. JFD have developed a stand-alone alarm and monitoring unit that measures the following parameters:• Supply pressure in cmH2O above barometric pressure• Patient lung delivery pressure cmH2O above barometric pressure• Supplied FiO2 percentage• Optional monitoring of expired End Tidal CO2 (ETCO2)• Barometric pressure for compensation of system pressure sensors• Monitoring of battery and mains supplied voltages with alarmsPressure readings are taken 100 times a second and use two separate proximal tubes that connect to the ventilator inlet and outlet through connection points. The use of proximal tubes ensures separation of sensors from the ventilator. With the high frequency and very high resolution /accuracy of pressure readings there are a number of parameters that can be derived or calculated in addition to primary measurements.

The stand-alone alarm and monitoring unit has backup batteries and provides a display of parameters and alarm status for all. The alarms can be set locally by the operator and an audible warning sounds when any are out of their valid range.With these alarms and sophisticated monitoring, any equipment failures or disconnections such as; gas supply failure, patient deterioration are immediately announced.

The unit has an Ethernet connection to allow a local laptop or monitoring computer to be connected for more comprehensive diagnostics, logging / history and visualisation of the patient’s condition. This connection also allows multiple ventilators to be connected to a network and data collected at a centralised monitoring point / station. This is particularly useful where multiple patients are being treated simultaneously, as is expected in reactive pandemic response.

There is no requirement for the alarm and monitoring unit or the laptop / PC for the correct operation of the ventilator. Even with a complete failure of these devices, the ventilator continues to operate by virtue of its purely gas flow control design.User interaction with the alarm and monitoring unit is simple to understand and explain. There is a continuous display of actual supply pressure and other parameters can be selected for view from PIP, VT, RR, FiO2, MV, PEEP. High and low adjustable alarms are available on all parameters. The operator does need to select which size of ventilator is in use so that the pressure readings can be related to the profiled performance of each size.

The unit is 250mm high and 150mm wide and can be attached to the patient’s bed with a hook- bracket or to a bedside stand. The front face is completely sealed and can be wiped clean for hygiene control. The alarm and monitoring unit is shown below:

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If higher than normal PIP is indicated for COVID-19 treatment how is this delivered?

Increasing the supply pressure will increase the PIP without affecting the PEEP value. A safe top limit of PIP should be maintained but at all times the mechanical safety relief valve protects the patient.

Can InVictoTM be used for Non-invasive Ventilation (NIV)?

Yes. The use of oral-nasal or full-face masks is possible for non-invasive applications. The system automatically compensates for mask leakage due to the switch point being a function of load (lung) pressure. The aerosol risks for NIV must be borne in mind however.

What about cleaning and infection control?

The ventilator is fabricated from a high temperature stable polymer and therefore is suitable for autoclaving. Production batches of ventilators will have a transparent cover plate allowing visibility of internal gas passages so blockages of build-up can be avoided. Depending on the treatment scenario and the total volume of ventilators being produced (from a cost perspective), the ventilator could be treated as a disposable item.

There is no need to install filtration to protect the ventilator for the above reasons; however a humidifying filter can be used if needed.

How does the InVictoTM react to endotracheal suctioning with a suction catheter?

The ventilator is unaffected by ET suctioning. As the ventilator is normally fitted to an extension limb the suctioning process is unhindered by the unit. The ventilator performance will be unaffected provided the tracheal seal is maintained.

How do you deal with a need to change ventilator size during a course of treatment?

As a patient’s condition varies during treatment there is the possibility that the MV, VT and PIP values are not being met through supply pressure adjustment and therefore a change of ventilator size will be needed. This is achieved by ventilator change out for a different size. This procedure will normally involve preparing a complete tested ventilator and limb assembly with the new ventilator. Swapping over connection hoses is easily achieved in a few seconds.

Re-starting ventilation after changeover is simply a case of reapplying supply pressure to the new ventilator assembly.

What if there is no available compressed medical air supply?

JFD can provide a gas distribution system to provide pressurised air suitable for supplying one or more ventilators. We have system designs for multi-place treatment of up to 24 patients on one ‘treatment cluster’.

Can InVictoTM be powered by an Oxygen Enrichment unit?

Possibly. Most oxygen enrichment units have a low discharge pressure but as the ventilator only requires a pressure of 200cmH2O there may be some units that provide pressures at this level.

How are operators trained in the use of InVictoTM systems and software?

Full system operating manuals are supplied with different language versions available. Training courses online or face to face can be provided by JFD or industry partners.

The InVictoTM system is very simple and safe to use and most experienced respiratory ICU clinicians will pick up the operation of the ventilator system easily.

Where are InVictoTM systems available from?

Initial systems are planned for delivery in early April 2020 to UK locations. Supply to other countries worldwide is planned through scaled-up manufacture in other regions. JFD have manufacturing facilities in Australia, Singapore, China, Europe, South Africa and the UK. Distribution partners are located in other areas including North and South America.

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