Technology overview

This briefing describes the regulated use of the technology for the indication specified, in the setting described, and with any other specific equipment referred to. It is the responsibility of healthcare professionals to check the regulatory status of any intended use of the technology in other indications and settings.

About the technology

CE marking

The Visensia physiological monitoring software (OBS Medical) is a class IIa device for which the manufacturer received a CE mark in November 2010, renewed in January 2015.


The Visensia physiological monitoring system is software that uses a standard Health Level 7 (HL7) interface for communicating to and from other data sources such as bedside monitors, central stations, telemetry kits and electronic patient records. This allows healthcare organisations to use existing patient monitoring and data infrastructures. It was originally marketed under the name BioSign; the change in name was not associated with any changes to the software itself.

Visensia analyses and interprets data from 5 vital signs:

  • heart rate

  • blood pressure

  • temperature

  • peripheral oxygen saturation

  • respiratory rate.

The vital sign data can be collected automatically and continuously from bedside monitors or taken at periodic intervals. Alternatively the vital sign data can be entered manually into the software. The data are combined to generate a single numerical index called the Visensia safety index (VSI), which can be displayed at the bedside monitor and at the nurses' central station. The VSI is based on a model of normality derived from a population of high‑risk patient groups on a general ward.

The VSI is recalculated and the alert status will update every time new vital sign data are received, continuously or periodically. The VSI ranges from 0 (no abnormalities) to 5 (severe abnormalities):

  • A score of less than 1 is considered normal and unlikely to be a cause for concern. However, if a patient has started with a score of 0 and a gradual increase to a score of 1 has been noted, this may merit investigation to see what has changed.

  • A score between 1 and 2 is moderately abnormal, and may merit investigation.

  • A score between 2 and 3 is indicative of a worsening condition for patients whose score was initially lower.

  • Any score above a threshold index of 3 will generate an alert. This is the clinically validated threshold that provides the best sensitivity and specificity for the early identification of deterioration and cannot be changed by users. The alert indicates that a single vital sign has changed by approximately 3 standard deviations from its normal value, or that 2 or more vital signs have changed by a smaller amount. The alert can be sent immediately for patients having periodic monitoring, or after a delay (for example, if the score persists for 4 out of 5 minutes). Staff are notified by an audible and visual alarm at the bedside and at the nurses' central station.

Visensia comprises 2 components, the Server and the Client. The Server has a minimum recommended specification for its use is as follows:

  • 2 GHz or better Pentium 4 equivalent processor

  • 1 GB or better memory

  • 10 GB free disk space

  • 100 Mb Ethernet connection.

The Server processes the vital sign data, and using the minimum recommended specification can process information from up to 500 beds. The Server has no graphical user interface; it runs as a service in the Microsoft Windows operating system, calculating the VSI and alert status for each patient as and when new data are received.

The Client has a minimum recommended specification for use as follows:

  • 1 GHz or better Pentium 4 equivalent processor

  • 512 MB or better memory

  • 1 GB free disk space

  • 10 Mb Ethernet connection.

The Client component of Visensia is a visual display of the patients being monitored, the patient data received, and the current VSI and alert status. It can be customised to display the beds in each room, ward or floor. The Client display includes the following information for each patient:

  • the name of the bed or room being monitored

  • the name and ID of the patient being monitored

  • each patient's latest VSI

  • warning indicators for the bed or room being monitored

  • index timestamp showing when the latest VSI was calculated

  • trend display of historic index values in graph or table form

  • pie chart showing the contribution of each vital sign to the current VSI

  • patient trend indicator indicating improvement or deterioration in the VSI over a period of time

  • alert status display shown on an alert control button (this is a coloured square which is red if there is a non‑silenced alert, gold when the alert has been silenced and green to indicate that the VSI has been calculated and it is neither alerting nor silenced)

  • an alert warning border for each patient (this is a coloured border around each patient's VSI, which flashes red to indicate an alert, grey to indicate a technical warning, gold to indicate a silenced alert, or green to indicate a normal state)

  • vital signs display showing a list of the current vital signs, values and times each vital sign was recorded for the patient

  • observation frequency change, which sets the observation frequency rate for the patient.

The information can also be viewed on a drill‑down display. This display includes a list of patients ordered according to the alert status and then the VSI. Selecting an individual patient from the list will show the vital signs and the VSI for that patient.

The Server can have an unlimited number of Client connections, meaning that it can be accessed from different computers around the hospital. When displaying data from several patients, the Client screen can be configured to show the data being received for each patient, their VSI and alert status. It can also be configured simply to provide an overview VSI and alert status of all patients monitored throughout the hospital.

Setting and intended use

The Visensia software is intended to be used by healthcare professionals for routine physiological monitoring of high‑risk adult patients who need level 1 and level 2 care on acute hospital wards, to provide an early warning of patient deterioration. Level 1 care includes patients at risk of their condition deteriorating, or those recently relocated from higher levels of care, whose needs can be met on an acute ward with additional advice and support from the critical care team. Level 2 care patients are those needing more detailed observation or intervention including support for a single failing organ system or post‑operative care and those 'stepping down' from higher levels of care.

Current NHS options

The NICE guideline on acutely ill patients in hospital recommends that adult patients in acute hospital settings should have physiological observations recorded and a monitoring plan written on admission (or initial assessment). Physiological observations should then be recorded at least every 12 hours, or more often if abnormal parameter values are detected. Multiple‑parameter or aggregate weighted scoring systems should include heart rate, respiratory rate, systolic blood pressure, level of consciousness, oxygen saturation and body temperature. This score is increased for any patient needing supplemental oxygen (oxygen delivery by mask or nasal cannulae; Royal College of Physicians 2012).

NICE is aware of the following CE‑marked devices that appear to fulfil a similar function to the Visensia monitoring system:

  • IntelliVue Guardian EWS (Philips).

  • Nervecentre (Nervecentre Software).

  • VitalPAC (The Learning Clinic).

  • Wardware (Airslie).

Costs and use of the technology

The cost of the Visensia software varies because it is tailored to meet the needs of each hospital. A number of purchasing models are available, including bed licence purchase and leasing via annual or monthly payment arrangements. The price for a 1‑bed perpetuity licence is £1950. As installations vary in size, individual quotes will be prepared to include installation and configuration charges. Maintenance and support is charged annually and is based on the number of beds licensed at the point of renewal. As a guide, for a 24‑bed level 1 facility there would be a £40,000 initial licence cost with an ongoing software service and support contract. For a 12‑bed level 2 facility, there would be an initial cost of £22,000 plus the software service and support contract. There is also a 1‑time installation charge which is generally around £2500. The software service and support contract is an annual fee calculated at 15% of the initial licence purchase. This would be £6000 per year for a 24‑bed facility and £3300 for a 12‑bed facility. This is payable for the period that Visensia is being used in the hospital.

Likely place in therapy

The Visensia software would be used as an adjunct to existing vital signs monitors and provide additional information as an aid to clinician decision making.

Specialist commentator comments

One specialist commentator noted that patients in high‑dependency units generally have a higher level of care than that normally provided on the wards; these patients are usually in the unit because deterioration (or the potential for it) has already been recognised. For this reason, the commentator felt that the software would be more useful in wards not necessarily designated or funded as high‑dependency unit areas, but where care is provided for patients who are considered to be high risk or level 1 to 2.

Another specialist commentator considered that the software should be used on all ward patients, because high‑dependency units will have a system in place for monitoring patients, and it is the ward patients that are more at risk of deterioration.

One specialist commentator pointed out that level 2 patients are more likely to have invasive monitoring, which may reduce the usefulness of a score calculated using non‑invasive measurements.

Equality considerations

NICE is committed to promoting equality and eliminating unlawful discrimination. In producing guidance, NICE aims to comply fully with all legal obligations to:

  • promote race and disability equality and equality of opportunity between men and women

  • eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief (these are protected characteristics under the Equality Act 2010).

Older age is associated with higher clinical risk. Physiological parameters are modified during pregnancy and therefore the VSI may be less reliable when used for pregnant patients. Age and pregnancy are protected characteristics under the Equality Act (2010).