140 Chapter 7 Animal A female Dutch Landrace pig weighting approximately 35 kg was used in this study. The pig underwent an acclimatization period of one week in the animal keeping facility prior to the experiment. During this period, the pig had free access to water but was fasted for 24 hours. For anesthesia induction, a combination of medications was administered intravenously. This included sufentanyl at a dosage of 0.01 mg/kg/h (Hameln Pharma GmbH, Hameln, Germany), Propofol at a dosage of 9 mg/kg/h (B. Braun Melsungen AG, Melsungen, Germany), and Midazolam at a dosage of 1 mg/kg/h (Aurobindo, Baarn, The Netherlands). These medications were used to induce a state of anesthesia in the pig. The pig was mechanically ventilated to ensure adequate respiration throughout the procedure. The ventilation was adjusted as needed to maintain appropriate oxygenation and ventilation. During the procedure, anesthesia was maintained using a continuous infusion of sufentanyl and propofol and additional doses were given whenever necessary. At the end of the experimental procedure, the pig was euthanized using a lethal dose of 200 mg/kg Pentobarbital (AST Farma, Oudewater, The Netherlands). Laser Speckle Contrast Imaging The PerfusiX-Imaging® device, developed by LIMIS Development BV (Leeuwarden, The Netherlands), was used for acquiring LSCI images. The system is designed to work in conjunction with standard laparoscopic equipment (Figure 1). For this study an Olympus laparoscopic video system (OTV-S190, Olympus, Hamburg, Germany) and a 30-degree laparoscope (EndoEye, Olympus, Hamburg, Germany) were used. LSCI is a non-invasive imaging technique that offers high spatial and temporal resolution for subsurface perfusion measurements 21. It can capture large surface areas without the need of a contrast agent. The technique leverages the coherent properties of laser light to provide real-time perfusion information. LSCI is a real-time 2D-perfusion imaging technique that relies on low power laser light to illuminate the tissue of interest. The laser light produces a random interference pattern, known as the speckle pattern, on the camera sensor. This pattern undergoes changes when underlying red blood cells move, corresponding to the rate of blood flow. Consequently, the blurring of the image or loss in contrast within the speckle pattern represents blood flow. Notably, the laparoscope was used without modification allowing the device to integrate into surgical practice. The device houses a red laser and allows for a fast, instant switching between conventional white light and laser light. As a result, 2D perfusion maps were generated in real-time and made directly available in the operating room. These maps provided visual representations of tissue perfusion, enabling immediate perfusion assessment and analysis during the surgical procedure.
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