instrumentation and monitoring techniques in femoral vascular access for hemodynamic assessment in a porcine model

通过 LPS 输注诱导猪内毒素血症的剂量依赖性

Sepsis and septic shock rank among the leading causes of mortality in patients receiving intensive care treatment1,2,3. Sepsis arises when an infection triggers a dysregulated immune response resulting in multiorgan failure. It is characterized by life-threatening symptoms, including hemodynamic instability, respiratory distress, hepatic and renal failure, as well as cognitive impairment4,5. Septic shock represents a subset of sepsis with particularly severe symptoms that significantly increase mortality. These symptoms include persistent hypotension requiring vasopressor therapy and a serum lactate level exceeding 2 mmol&#8729;L-1&#160;4,5. Mortality rates in patients with septic shock have been estimated as high as 40%, even with hospital treatment1,3,5.
Gram-negative bacteria, such as Pseudomonas and Escherichia coli, often cause infections triggering this dysregulated immune response4. The underlying pathophysiological mechanisms are complex and not yet fully understood. One well-described aspect involves the activation of Toll-like receptors on immune cells by pathogen-associated molecular patterns (PAMPs), leading to the release of cytokines such as tumor necrosis factor-alpha (TNF&#945;) or Interleukin 1 (IL 1)4. One of these PAMPs is lipopolysaccharide (LPS), which constitutes a component of the cell membrane in gram-negative bacteria6. LPS has been employed in animal models to induce endotoxemia and endotoxemic shock7,8.
Animal models provide a controlled and standardized setting to develop and investigate novel treatment strategies. Due to its similar anatomy, immunological physiology, and comparable hemodynamic parameters, the pig model is particularly well-suited for studying the effects of endotoxemic shock9,10. Furthermore, standard medical equipment commonly used in human patients can be readily applied in pigs due to the similar size of their airways and blood vessels, facilitating instrumentation and hemodynamic monitoring.
With this protocol, we provide an experimental model for endotoxemic shock in pigs by intravenously infusing LPS derived from E. coli. To monitor the effects, we measured hemodynamic and pulmonary parameters, including arterial blood pressure, heart rate, peripheral oxygen saturation, pulmonary arterial pressure, and airway pressure. To evaluate the influence of endotoxemia on cerebral oxygen supply, we used near-infrared spectrometry (NIRS). With this method, the cerebral oxygen saturation can be evaluated via an adhesive electrode applied to the forehead11.

作者聚焦：猪实验性内毒素休克的诱导，用于研究血流动力学和呼吸衰竭

脂多糖输注作为猪内毒素血症休克模型

With this protocol, we induce experimental endotoxemic shock in pigs. We were able to reliably cause symptoms of endotoxemia, such as hemodynamic instability and respiratory failure. Lipopolysaccharide is a toxic substance.When working with lipopolysaccharide, it is essential always to wear gloves, protective goggles, a mask, and a lab coat. This protocol provides an easy and reliable way to induce endotoxemia. Because of their similar anatomy and physiology, pigs are particularly well-suited for this kind of research as standard medical equipment may be used.Using this protocol, we will be able to study the effects of different ventilation strategies in respiratory failure and lung damage during endotoxemic shock.

猪模型中用于血流动力学评估的股血管通路的仪器和监测技术

首先，将麻醉的猪仰卧放在工作平台上。将酒精消毒剂涂抹在腹股沟区域，然后用无菌拭子擦拭。然后涂抹消毒剂并等待三分钟，然后在腹股沟区域放置无菌开窗布。使用超声波识别股血管并纵向观察它们。接下来，用连接到针头的注射器刺穿股静脉，并用缓慢流动的暗红色血液确认静脉穿刺。将电线插入静脉并取出针头，同时将电线留在原位。然后用连接到针头的注射器刺穿动脉以进行连续抽吸。用鲜红色的脉动血液确认动脉穿刺。从动脉中取出注射器并插入准备好的电线。然后取下针头，同时将电线留在原位。使用超声波观察股血管，以确认两根导线的正确定位。接下来，使用 Seldinger 技术将动脉引诱导器鞘插入股动脉，将静脉引诱导器鞘插入股静脉。为了确认正确的位置，从动脉和中心静脉管路中抽取血液进行血气分析。接下来，用生理盐水冲洗管路以防止凝块形成。使用手术缝合线将线条固定在皮肤上，以防止脱位。将动脉和中心静脉管路连接到换能器以进行血流动力学测量。将脉搏轮廓心输出量或 PICO 导管插入动脉导引物鞘中。将导管连接到动脉压力传感器和 PICO 监护仪的温度接口电缆。在连续测量压力的同时，将 Swan-Ganz 导管插入中心静脉诱导器鞘中。一旦导管插入约 30 厘米，并在出现中心静脉压曲线时，给球囊充气。缓慢地将导管推进到中心静脉导引器鞘中，同时监测压力曲线。导管进入右心室后，检查脉搏曲线是否具有高收缩压和低舒张压。为了确认导管在肺动脉中的位置，请进一步推进导管并寻找一致的收缩压和增加的舒张压。将导管固定到位，并将PICO系统的注射液温度传感器连接到Swan-Ganz导管的近端管腔。

instrumentation-monitoring-techniques-femoral-vascular-access-for

Research

JoVE Journal

Medicine

Instrumentation and Monitoring Techniques in Femoral Vascular Access for Hemodynamic Assessment in a Porcine Model

84 Views.  University Medical Center of the Johannes Gutenberg-University. To begin, place the anesthetized pig supine on a working platform. Apply an alcoholic disinfectant to the inguinal area and wipe it with a sterile swab. Then apply disinfectant and wait three minutes before placing a sterile fenestrated drape over the inguinal area.Using ultrasound, identify the femoral blood vessels and visualize them longitudinally. Next, puncture the femoral vein with a syringe attached to the needle and confirm venous puncture with slow-flowing, dark red blood. Ins...

Video: Instrumentation and Monitoring Techniques in Femoral Vascular Access for Hemodynamic Assessment in a Porcine Model

Lipopolysaccharide Infusion as a Porcine Endotoxemic Shock Model

Sepsis and septic shock are frequently encountered in patients treated in intensive care units (ICUs) and are among the leading causes of death in these patients. It is caused by a dysregulated immune response to an infection. Even with optimized treatment, mortality rates remain high, which makes further insights into the pathophysiology and new treatment options necessary. Lipopolysaccharide (LPS) is a component of the cell membrane of gram-negative bacteria, which are often responsible for infections causing sepsis and septic shock. 
The severity and high mortality of sepsis and septic shock make standardized experimental studies in humans impossible. Thus, an animal model is needed for further studies. The pig is especially well suited for this purpose as it closely resembles humans in anatomy, physiology, and size. 
This protocol provides an experimental model for endotoxemic shock in pigs by LPS infusion. We were able to reliably induce changes frequently observed in septic shock patients, including hemodynamic instability, respiratory failure, and acidosis. This will allow researchers to gain valuable insight into this highly relevant condition and evaluate new therapeutic approaches in an experimental setting.

We provide a protocol for an experimental endotoxemic shock model in pigs by infusion of lipopolysaccharide.

Sepsis and septic shock are frequently encountered in patients treated in intensive care units (ICUs) and are among the leading causes of death in these ...

科研

医学

To begin, place the anesthetized pig supine on a working platform. Apply an alcoholic disinfectant to the inguinal area and wipe it with a sterile swab. Then apply disinfectant and wait three minutes before placing a sterile fenestrated drape over the inguinal area.Using ultrasound, identify the femoral blood vessels and visualize them longitudinally. Next, puncture the femoral vein with a syringe attached to the needle and confirm venous puncture with slow-flowing, dark red blood. Insert the wire into the vein and remove the needle while leaving the wire in place.Then puncture the artery with a syringe attached to the needle for continuous aspiration. Confirm the arterial puncture with bright red, pulsating blood. Remove the syringe from the artery and insert the prepared wire.Then remove the needle while leaving the wire in place. Using ultrasound, visualize the femoral vessels to confirm the correct positioning of both wires. Next, use Seldinger's technique to insert the arterial introducer sheath into the femoral artery, and the venous introducer sheath into the femoral vein.To confirm proper positioning, draw the blood from the arterial and central venous lines for blood gas analysis. Next, flush the lines with saline to prevent clot formation. Secure the lines to the skin using surgical sutures to prevent dislocation.Connect the arterial and central venous lines to transducers for hemodynamic measurements. Insert a pulse contour cardiac output, or PICO catheter, into the arterial introducer sheath. Connect the catheter to the arterial pressure transducer and the temperature interface cable of the PICO monitor.While continuously measuring pressure, insert the Swan-Ganz catheter into the central venous inducer sheath. Inflate the balloon once the catheter is inserted approximately 30 centimeters, and upon the appearance of a central venous pressure curve. Slowly advance the catheter into the central venous introducer sheath while monitoring the pressure curve.Once the catheter enters the right ventricle, examine for a pulse curve with a high systolic and low diastolic value. To confirm the placement of the catheter in the pulmonary artery, advance the catheter further and look for a consistent systolic and an increased diastolic value. Fix the catheter in position and connect the injectate temperature sensor of the PICO system to the proximal lumen of the Swan-Ganz catheter.

Shock Induction and Treatment of Hemodynamic Instability in a Porcine Model Using LPS Infusion and PiCCO Monitoring

After inserting the Swan-Ganz catheter into the pulmonary artery, allow the anesthetized pig to stabilize for 30 minutes. Then obtain the baseline hemodynamic measurements. Administer 150 micrograms per kilogram of lipopolysaccharide or LPS for 30 minutes.Monitor the hemodynamic parameters such as arterial and pulmonary arterial blood pressure, heart rate, and ventilation. Then monitor the hemodynamic parameters at an LPS infusion rate of 15 micrograms per kilogram per hour. On the PiCCO monitor, press the thermodilution button, then press the button for central venous pressure or CVP input, and enter the current CVP value before pressing the Start button.When prompted, inject 10 milliliters of cold saline solution into the injectate temperature sensor connected to the Swan-Ganz catheter. After measuring cardiac index, global end-diastolic index, and extravascular lung water index, apply hemodynamic instability treatment according to the flow chart. In case of volume loading, rapidly infuses 200 milliliters of balanced electrolyte solution.For catecholamine therapy, increase the norepinephrine infusion rate by one microgram per kilogram per hour. Mean arterial blood pressure decreased following LPS infusion, but was maintained above 60 millimeters of mercury through fluid resuscitation or norepinephrine infusion. The animals demonstrated a decrease in cardiac index and an increase in heart rate, indicating hemodynamic instability during the shock state.Lung damage was indicated by a decrease in the partial pressure of oxygen and the arterial blood inspiratory oxygen fraction ratio, and an increase in pulmonary artery pressure. Cerebral oxygenation also decreased following the induction of shock. The animals also exhibited acidosis and increasing lactate levels.