V-Sign System Sentec2018-06-21T04:08:37+00:00

Overcoming limitations of arterial blood gases, etCO2 and SpO2 monitoring

Arterial blood gas analysis

is invasive and only provides snap-shot information on the patient’s condition. It is vital to provide continuous monitoring of critically ill patients, whose condition may change rapidly. Furthermore, frequent arterial blood gas analysis is associated with blood loss.

End-tidal CO2 (etCO2) monitoring

Measurement of etCO2 is mostly suitable for patients with healthy lungs who have good lung perfusion and ventilation. This is, however, not true in cases such as patients suffering from COPD or ARDS, or patients undergoing one-lung ventilation.

has its limits for patients with chronic respiratory failure due to ventilation-perfusion (V/Q) mismatch. The monitoring of etCO2 also depends on the gas sampling quality (leak-free masks and tubing) and requires regular/full breathing cycles to reflect alveolar CO2.

Capnography is sometimes inefficient to screen patients for nocturnal alveolar hypoventilation and hypercapnia. Furthermore, etCO2 measurements are often inaccurate in patients receiving noninvasive ventilation (NIV) or in patients who are breathing spontaneously.

Measuring SpO2 alone

 is not sufficient to detect hyperventilation or hypoventilation. Due to the S-shape of the oxygen dissociation curve, hypoventilation with a decrease in the PaO2 may not be noticed over a period of time. Especially with the administration of supplemental oxygen, patients can show adequate arterial saturation during hypoventilation. Changes of arterial CO2 levels can never be detected by SpO2 monitoring alone. Pulse oximetry doesn’t give information about hypoventilation and hyperventilation. Even the combination of SpO2 and daytime arterial blood gas are not reliable tools for detecting nocturnal hypoventilation, which can occur during long-term NIV and in patients with suspected ventilatory failure.

Noninvasive, continuous monitoring

Combined tcPCO2 and SpO2 measurement is an easy and reliable way to assess patients’ ventilation and oxygenation status.

Advantages of digital tcPCO2 and SpO2 monitoring

The Digital SenTec V-Sign™ Sensor 2 is a Stow-Severinghaus-type PCO2 Sensor combined with reflectance 2-wavelength pulse oximetry. The highly integrated digital sensor head comprises a micro pH-electrode and an optical oximetry unit. The sensor temperature is regulated by two independent temperature sensors. All data is digitized in the sensor head, allowing the transmission of robust, low-noise signals to the monitor. Sensor sensitivity and calibration data is stored in the sensor head during manufacturing and regularly updated during use. Automatic sensor calibration ensures that the system is “Ready for use” when needed and allows for a long measuring time of up to 12 hours.

Triple parameters – the V-Sign™ Sensor 2 providescontinuous, noninvasive measurement of tcPCO2, SpO2 and pulse rate (PR). Information about the pulsation index and Heating Power are also available

Accurate and reliable

Excellent accuracy

SenTec’s sophisticated algorithms ensure high accuracy and minimal technical drift. Additionally, the V-STATS™ software provides a retrospective residual drift correction. In a 2012 study, Prashant N. Chhajed et al. demonstrated that the SenTec Digital Monitoring System provided accurate results compared to conventional blood gas analysis.


SenTec‘s unique transcutaneous artifact detection algorithm provides reliable data when conventional tcPCO2 monitors tend to fail.

Fig. 2 above shows a comparison of tcPCO2 and PaCO2. Measurements were compared using both a Bland-Altman plot (left panel) and linear regression analysis. The Bland-Altman plot displays the mean bias and limit of agreement (solid lines). The linear regression plot displays the line of best fit (solid line) and the identity line (dashed line).

SenTec’s Digital Monitoring System offers intuitive controls and easy-to-read displays.

Tracking changes in therapy

The monitor allows for setting a baseline and markers just before changing the treatment of patients. The impact on patients’ ventilation and oxygenation can thus be objectively and easily assessed.

Display of values / online trends

of tcPCO2, SpO2, pulse rate (PR) and Relative Heating Power (RHP).

Baseline and Delta values

Displays show a numerical indication and graphical representations of the difference between the current reading and the previously set baseline.

Easy to use

The SenTec Digital Monitoring System has a number of practical and time-saving features.

Choose from multiple
validated measurement sites

Safe and gentle sensor application

Multi Site Attachment Ring

Single-use ring for the attachment of SenTec transcutaneous sensors to various measurement sites.

Staysite™ Adhesive

Additional adhesive film to improve fixation of Multi Site Attachment Ring in challenging settings.

Ear Clip

A great solution for overnight monitoring in sleep labs as well as long-term use. Attached to the ear lobe, the sensor doesn’t disturb sleep and is suitable for patients wearing masks.

Freely rotatable sensor

Once the sensor is inserted into the Multi Site Attachment Ring, it is rotatable. This gives the caregivers more flexibility to adjust sensor cable positioning during sensor attachment and monitoring.

The Smart Calmem

As the calibration data is stored in the sensor head, it can be disconnected for up to 30 minutes without the need for recalibration.

Portability and transportability

Recalibration intervals range up to 12 h.

Recalibration intervals range up to 12 h.

Portability and transportability

Lightweight monitor, mountable on rollstands or infusion stands, and battery life of up to 10 hours allows continuous patient monitoring during intra-hospital transport or in situations when no AC power is available.

Quick system setup

Up to four preset or customizable profiles can be stored and selected on the SenTec Digital Monitor.

Central monitoring

V-CareNeT™ System enables remote monitoring and alarm surveillance for up to 40 SenTec Digital Monitors. This provides an increased level of safety to patients, disturbance free monitoring (e.g. in sleep lab settings) and improved workflow for caregivers.

Wide range of medical applications

Clinical studies underscore the growing acceptance of transcutaneous CO2 monitoring in many application areas.

Valuable insights

Making treatment decisions based on data analysis.

V-STATS™ software enables users to download trend data from the internal memory of the monitor and display it on the PC screen for further analysis, reporting, and generation of a printable report. Data download is possible via serial or LAN interface. Parameters and safety relevant settings such as alarm system management, site time and temperature management are easily configured and saved/stored as user profiles within the V-STATS™ software. All departments can have their specific profiles to support their transcutaneous monitoring requirements – all within the same SenTec device. Profile settings and reports may be easily generated, duplicated, printed and emailed.

The V-STATS™ software streamlines processes and enhances workflow efficiency in multiple clinical settings such as respiratory care and sleep studies. The V-CareNeT™ System enables remote monitoring and alarm surveillance for multiple SenTec Digital Monitors (SDMs). The central station is the PC running V-STATS™ with activated V-CareNeT™ Package.

Broad connectivity

Patient data from the SenTec Digital Monitor can be transferred to bedside monitors, PCs, nurse call systems, chart recorders or data loggers.

Polygraphic (PG) and polysomnography (PSG) systems

Various ready-made adapter cables and interfaces are available to connect the SenTec Digital Monitor to the most common PG or PSG systems, including innovative wireless solutions with Nox Medical.

Connectivity to patient monitoring systems and electronic medical record systems (EMR)

Monitored data from SenTec Digital Monitor can be transferred to selected

• patient monitoring systems (Philips, Dräger, Mindray and Spacelabs) or
• electronic medical record systems (e.g. via Capsule).

For more information, please refer to the following link:

A current list of connectable patient monitoring systems is on our website: