A New approach of tissue perfusion
IKORUS® is an innovative monitoring system that allows physicians to better assess intestinal tissue perfusion and could serve as a possible guide for novel circulatory therapies, both in intensive care medicine and high-risk surgery.
Because microcirculation states can sometimes be decorrelated from systemic hemodynamics, the use of IKORUS® could target new approaches of resuscitation, based not only on arterial pressure- based endpoints, but also tissue perfusion-based endpoints.
Enhanced Individualization of Arterial Pressure value targets
Better optimization of Fluid-loading strategies
Titration of drugs upon effects on tissue perfusion
Detection of cryptic ischemic events
How does it work?
The probe consists of a duodenal feeding tube with a photoplethysmographic sensor (cf fig.1) mounted inside a balloon placed at the distal end of the probe.
The balloon is automatically inflated in the duodenum so that the photoplethysmographic sensor abuts the intestinal wall.
The photoplethysmographic sensor is composed of:
- An infrared LED for the emission
- A photodiode for the measurement
The wavelength of the infrared LED is highly sensitive to the oxyhemoglobin, almost 50% more than to the hemoglobin.
Once the sensor is suitably placed against the gut wall, the LED will emit in infrared light that will transit trough the intestinal villi before reaching back the sensor (see Fig.2). The light absorption is determined by the absorptivity of the arterial blood, the venous blood and the parenchyma. Therefore, the remaining light measured by the sensor reflects the total absorption of the villi. Local microcirculation is computed using an approach that breaks down the signal into a static part (DC) and a dynamic part (AC) of the absorbance . The DC part is composed of static blood and the tissue while the AC is composed of the pulsatile part.
The main perfusion indicator (GBF) is calculated from the pulsatile part of signal which reflects the pulsatile blood.
The area under the pulsatile signal is supposed to be proportional to the quantity of blood travelling in front of the sensor through the cardiac cycle. Due to the high sensitivity of infrared light to HbO2 and the fact that it integrates the pulsatile blood, the area under the curve reflects the quantity of arterial oxygenated blood flow arriving near the cells.
Gut Pulsatile Blood Flow Index (GBF) represents the Area under the pulsatile part per unit of time (min), representing the quantity of pulsatile blood in front of the sensor during one minute
The system consists in 2 different devices that used in conjunction:
- Single use disposable probe
- Photoplethysmographic sensor at extremity
- Duodenal placement
- Pressure-controlled inflation of distal balloon ensures optimal contact of sensor contact with mucosa
- Iterative deflation cycles = safety of use for patients by releasing pressure on tissue
- Enteral nutrition preserved
- Stand-alone monitor
- Specific algorithmic for processing of electronic data sent by duodenal probe
- Displays unique information pertaining to gut perfusion
- Allows long-term and short-term analysis of perfusion trends
- Pneumatic circuitry for automatic pressure control of balloon
Last update : 07/09/17