Subtilis – introduction

Subtilis is a major new development in oxygen monitoring. Subtilis will improve oxygen therapy and reduce bed occupancy. It will enable oxygen therapy guidelines and protocols to be followed with greater surety.

Subtilis (Latin – precise) creates personalised calibration data for each patient episode thus making it independent of sensor and patient variability. It incorporates proven technology within patent protected innovative development.

Subtilis Technology Overview

• In conventional pulse oximetry if the spectral properties of the sensor do not match the R curve in the monitor the system will not be accurate.
• Biological errors in conventional pulse oximetry arise from a mismatch between the individual patient parameters and the R curve in the monitor.
• Subtitlis technology calculates a R curve based on sensor spectral properties and patient parameters.
• The heart of the Subtilis system is proven Lightman technology

Unique Selling Points of Subtilis technology

• Subtilis algorithms for creating r curves for each patient sensor combination are unique.
• The improved performance will mean that patients’ safety will be improved, bed occupancy will be reduced, emergency decisions will not have to wait for blood gas data, and it will be possible to follow guidelines and protocols on oxygen therapy with greater surety.
• This technique is not limited to oxygen saturation alone. It can be applied to carboxy haemoglobin, met haemoglobin etc.
• Subtilis technology is not compromised by overlapping absorption spectra in the way that some alternative techniques are.
• Whether patient parameters are identified automatically or manually our technology can react to this information by generating the appropriate calibration data.
• The Subtilis is based on proven technology used in The Lightman. The Subtilis is up and running, and is ready for commercialisation.

How does Subtilis technology work?

• Monitors rely on sensors working within prescribed wavelengths. This is flawed.
• Inaccuracies in current pulse oximetry devices limit their application and compromise patient safety
• By building our technology into a monitor it is calibrated to work perfectly with each sensor every time
• The monitor is able to analyse the specific wavelengths of each individual sensor and generate a new R curve for that sensor
• Each R curve generated also takes into account the patient parameters encountered such as skin colour and haemoglobin types
• Ability to allow for presence of non-functional haemoglobin such as Carboxy Haeoglobin and/or Methaemoglobin
• Accuracy, reliability and functionality are increased dramatically – pulse oximetry becomes a robust and flexible diagnostic tool.
• A different tool. A new tool.

Medical Benefits and Efficiencies

Subtilis technology is set to revolutionise the Global non invasive blood oxygen monitoring market by:

• Reducing false oxygen alarms by up to 51%
• Improving patient outcomes in up to 87% of cases
• Reducing late interventions in up to 23% of cases
• Reducing unnecessary interventions by up to 64%

All of the above will significantly increase healthcare efficiencies and improve patient outcomes.

Clinical Decisions based on SATs values

10 years ago pulse oximetry was used as a guide. If SATs levels were seen to be falling then the levels would be confirmed by blood gas analysis. There has been a change in user’s expectations. Clinical professionals expect to be able to base decisions on pulse oximetry data.

Pulse oximetry is now being used in a wider range of clinical scenarios. Patients are treated and managed at much lower oxygen saturations – where pulse oximetry inaccuracies are greatest. There is a move towards the use of Guidelines and Protocols by staff who may have less clinical experience and place greater reliance on monitoring equipment.

Example Guideline Targets

• 98% upper end target range for acutely ill ‘healthy’ adult.
• 95% Upper limit for higher range for BOOST ll trial. Patient with stroke lower limit.
• 94% GPs admit children to hospital. Hospitals discharge patients.
• 92% upper level of range for hypercapnic risk patients. GPs admit adults to hospital. Lower limit for elder adult patient.
• 91% lower limit for higher range in BOOST ll trial.
• 90% common upper limit for neonatal units.
• 89% upper limit for lower range in BOOST ll trial.
• 88% lower limit commonly used on neonatal units. Lower limit for hypercapnic adults.
• 85% lower limit for the lower range in BOOST ll trial.
• 82% target SATs for extremely premature babies in some hospitals.

These guidelines demand high accuracy for oxygen monitoring. Variations in patients SATs values can rapidly lead to changes in management options. Inaccurate pulse oximetry systems can contribute to inappropriate management and intervention.

High reading systems can lead to deferred oxygen administration or delay additional procedures. Low reading systems could lead to increased or prolonged therapy e.g. intubation and ventilation.

• Present claims for pulse oximetry do not meet the demands of the guidelines – errors of +/- 2 to 3% do not give sufficient definition between management groups.
• Errors introduced by sensors and patient variability compound the problem.

Pulse oximeter manufacturers claim an accuracy of Arms values of +/- 2 to 3% over the range of 70% to 97% oxygen saturations. Users understand this to be +/- 2 to 3% at any point in the stated range (as the red and blue lines in the graph). In practice the error is smaller at higher oxygen levels and greater at lower oxygen levels. Sensors with different spectral characteristics to those intended introduce a systematic high or low reading bias in the conventional pulse oximeter system. The variability due to different patients (+/- 2 to 3%) will apply to the biased results. If the error is +/- 2% and the bias for a particular sensor is +4 then the patient sensor combined error becomes +2 to +6.

Subtilis technology brings all sensors to the same high level of accuracy regardless of their spectral properties (within reason). Whilst the errors discussed above could cause a conventional pulse oximeter system to be a risk to patients, these errors will not affect the Subtilis system. Similarly patient variability can compromise conventional pulse oximetry. The Subtilis will cater for variations in patient parameters.

Current pulse oximetry technology will be rendered obsolete.

Conventional Pulse Oximetry - Fixed R Curve

In conventional pulse oximetry the r curve is determined during the design phase and is stored in the monitor. If sensor spectral properties vary from the sensor used in the original design the sensor can be considered not to match the r curve in the monitor and the system will lack accuracy. Similarly if patient parameters vary from the parameters represented in the breathe population that was used to create the calibration data, accuracy will be compromised.

Subtilis system - R Curve Construction

In Subtilis technology the spectral properties of the sensor are used to create calibration data for that sensor. Additionally if patient parameters such as the presence of melanin and/or non-functional haemoglobins are known the calibration data for the sensor system can be further refined. This results in unique calibration data for each patient sensor combination leading to vastly improved accuracy of data. This process can be applied not only to oxygen saturation but also to other blood parameters.

Video

A demonstration of the prototype Subtilis is available below. We are offering a unique opportunity to acquire this technology. Please contact us for further information.

The following patents are granted.
European Patent No, 0898932, which covers many European countries, including the UK, Austria, Belgium, Switzerland / Liechtenstein, Germany, Denmark, Spain, France, Ireland, Italy, Luxembourg, The Netherlands, Portugal, Sweden and Finland. Additional related patents have been granted under numbers US 6 133 994, Austria E296053, Germany DE 698 30 283.4-08 and Spain 2244034.

UK and International Patents pending - UK Patent Application Numbers 0618547.4 and 0710885.5.