Monitoring of Systemic and Hepatic Hemodynamic Parameters in Mice

In this film, the procedure of monitoring systemic and hepatic hemodynamics and mice is demonstrated. Monitoring includes acquisition of vital parameters, systemic blood pressure, central venous pressure portal vein pressure, as well as the portal flow rate in mice. What is Needed for the full monitoring procedure is a computer with lab chart seven, a stereo microscope and anesthesia machine and a DI system.

Components A DI system. Components include transit time, perivascular, flow meter, power lab, and quad bridge. For data acquisition, we also need temperature and ECG signal conditioner for recording, directive temperature and heart rate.

Here are the instruments we need. Suture materials we need are six zero silk six zero proline seven zero proline, 10 zero proline. This is the temperature sensor, ECG sensor and respiratory sensor.

This is the blood flow probe, MA one PSB for measuring the flow rate of portal vein. This is the blood flow probe, MA 0.5 PSB for measuring the flow rate of common he body artery, carotid artery and uug vein. This is the Milli C Theater, a highly sensitive pressure transducer for measuring the blood pressure.

Milli C theater calibration. Connect one Miller sensor to the Miller two channel, which is set for acquiring portal vein pressure. Insert the Miller sensor tip into water column millimeter.

First, set the water Column value to zero centimeter water in lab chart seven window. Choose bridge amplify and zero It.Run the progress And then stop. And that way we can get the baseline value to zero centimeter water.

Then set the water column value to 20 centimeter water. Run the progress and then stop here. The baseline of 20 centimeter water column is shown.

Choose units in the window. Set the baseline of zero and 20 centimeter water to the corresponding voltage value. Adjust the unit to centimeter water blood flow probe calibration.

Put the probe into deionized water. Connect the probe with transonic flow probe system and lab chard window. Choose input amplify to zero the flow probe.

Adjust the units. Press the button to test Channel to collect the signal. If the signal has three to four bars, it means the signal is good.

In case a good signal is acquired, we can proceed further. Press the button to see road channel and scale channel to see whether the value has been calibrated or not. Press the button To measure channel for later measuring and Ize the mouse with 2%ISO fluorine and 0.3 milliliter per minute oxygen.

Fix the mouse on the operation table with warming pad. Place a gauze cushion under the neck for optimal exposure of the operation field. Insert the ECG needles subcutaneously into the pause.

Place the respiratory sensor under The back of the mouse. Place the temperature probe into the rectum of the mouse. Record mouse temperature ECG and respiratory rate in lab.

Chart seven neck operation for systemic cardiovascular monitoring. Disinfect the neck of the mouse. Identify the middle line of the neck, middle point of the clavicle, the angle of the mandible.

Make a two centimeter longitudinal incision from the angle of the mandible to the middle point of the clavicle about 0.5 centimeter on the left side of the middle line. This animation will demonstrate the anatomy of the neck. We can identify the submandibular gland immediately after opening the incision.

After turning over the submandibular gland, we can identify the external ular vein and its branches. Under the ular vein, we can see the muscle layer, including the sternal lato mastoid muscle, the superior belly of the omohyoid and the sternal hyoid muscle. After pulling these muscles aside, we can identify the carotid artery play special focus on the carotid artery and the external ula vein.

These two vessels are needed for the insertions of the ceds. Here we will demonstrate the surgical procedure. First, Dissect the sub gland, turn it over And cover it with saline socked gauze.

We can identify the external eula vein. Immediately dissect the ugla vein and place 3 6 0 silk sutures, one for ligation and the other two for fixing. Free the vessel wall by clipping the fat tissue on the surface of the vein.

Make sure not to injure the vessel wall, otherwise it will cause severe bleeding. Then Separate the sternal Plato mastoid muscle superior belly of omohyoid and stern oid muscle. Pull the sternal mastoid muscle aside with a retractor.

Then we can identify the carotid artery. Dissect the carotid artery and place three sutures for fixing and ligation with six zero silk carotid artery blood flow measurement. Place the transonic probe MA 0.5 PSB around the carotid artery.

Keep it stable. Optimize the contact using ultrasound gel or saline. Record blood flow rate of carotid artery as indicated on the small screen of the transonic device.

Using lab chart seven, remove the probe after completing the measurement. Carotid artery pressure measurement ligate the distal end of the carotid artery clamp. Its proximal end.

Tie the fixing sutures loosely for later. Fixing the Millia Theater Place one lifting suture using 10 zero proline on the anterior wall. To facilitate opening the incision, make a small incision on the anterior wall of the vessel.

Insert the Millia Theater and fix it. Release the clamp. Record the carotid artery pressure using left chart seven ulo vein blood Flow measurement.

Measure the ulo vein blood flow by using Transonic flow rope MA 0.5 P sb. Record the Flow rate. Remove the probe After completing the measurement, Central veinous pressure measurement Clamp the proximal end of the ular vein like ligate the distal end.

Cut a small incision using micro scissors. Insert the fluid filled catheter, fix it With a pre placed suture lines. Release the clamp.

Record the central venous pressure Abdominal operation for acquisition of hepatic hemodynamics. Make a transverse incision on the abdomen. Move out the intestines to the left side and cover it with wet gauze.

After moving out the intestines, we can identify the inferior vena kava, the portal vein, the common hepatic artery and the proper hepatic artery portal blood flow measurement. Dissect the portal vein. Place six zero silk suture under the portal vein to facilitate lifting of the vessel.

Place the flow probe MA one PSB around the vessel. Measure its blood flow rate. Record the data, Remove the probe.

After completing the measurement, common hepatic artery flow measurement, identify the common hepatic artery, dissect It cautiously. Place 1 6 0 Silk suture to facilitate lifting of the vessel. Place the flow probe MA 0.5 PSB.

Measure its blood flow and acquire the data. Remove the probe After completing the measurement portal, vein Pressure measurement, choose one branch of the mesenteric vein with few site branches, which drains straight into the portal vein as shown in the animation place. Two fixing sutures around the vein.

They will later serve for fixing the milli cedar Place. Two stay sutures using 10 zero proline. We can also place one lifting suture on the interior wall of the vein, which should facilitate lifting of the front wall.

To fully open the incision, make a small incision on the vein using micro scissors. Insert the milli CED to the mesenteric vein. Advance to the confluence of the portal vein to acquire the portal vein Pressure.

Now we Will demonstrate the surgical procedure of measuring the portal. Vein pressure ligate the distal end of the selected mesenteric vein. Ligated small branches placed two Fixing sutures using six zero proline.

The key point of this procedure is to avoid touching of the mesenteric artery. When ligating the vein clamp, the proximal end of the vein. Place two stay sutures using 10 zero proline on both sides of the vein.

Some bleeding will occur since the stay sutures should penetrate the vascular wall of the fine mesenteric vein. Use fine micross to make a small incision obliquely at a 45 degree angle. Insert the milli C theater gently and fix it.

Release the clamp. Insert the milli C Theater until reaching the confluence of the portal vein record the portal vein pressure. The cathed can stay in place until the end of the experimental procedure conclusion.

Despite the small size vital parameters, systemic and hepatic hemodynamics can be monitored even in mice. Up to now, this procedure we used is suitable to assess hepatic hemodynamic effects in acute or final experiments. We have already collected normal hemodynamic parameters of mice and applied this procedure on 70%partial hepatectomy and liver loop clamping.

Experiment to observe liver perfusion changes. Vital parameters such as respiratory rate, heart rate are obviously much higher than in red, means systemic blood pressure and ullal vein pressure are similar as in reds and even similar to the human data. Hepatic hemodynamic data are obviously different.

Total blood flow and normalized ranges between 1.6 and 2.3 milliliter per minute Flow in the hepatic artery ranges normally from 0.1 to 0.35 milliliter per minute. Portal pressure is in range from 4.4 to 11.2 centimeter water, the mean portal vein pressure before and after 70%partial hepatectomy with 6.9 and 11.4 centimeter water, which was coincident with the variations in human or other experimental animals. It indicates that this direct monitoring procedure is sensitive and accurate to assess these hemodynamic parameters.

The results of clamping liver lobe experiment showed that the small changes of hepatic perfusion could be detected by this monitoring procedure. Therefore, this procedure can be used in many experimental research fields such as hepatobilliary surgery and pharmacological intervention to document hemodynamic changes.Subsequently.