Measurement of Pulmonary Artery Pressure in Rats Using Right Heart Catheterization
December 16th, 2025
The protocol provides a detailed introduction to the experience of using the right heart catheterization method to detect pulmonary artery pressure in rats, which will help to obtain accurate data more efficiently and improve the success rate of the experiment. This method also improves the reproducibility of experiments across different laboratories.
Our laboratory has optimized the traditional right heart catheterization procedure in many ways to improve efficiency and success rate. The challenge is that the technique of measuring pulmonary arterial pressure in small animals using right heart catheterization is difficult for beginners to master. To begin, use scissors to cut off the needle tip of a venous infusion set with a PVC tube measuring 1.6 millimeters in outer diameter, one millimeter in inner diameter and 25 centimeters in length.
Thread a copper wire with a diameter smaller than one millimeter into the polyvinyl chloride tube. Wrap the tail end of the tube around a cylindrical object such as a pencil to form a circle with a diameter of seven millimeters, and immerse the circular end in water, heated to 100 degrees Celsius for 10 minutes. After heating, remove the tube from the water.
Then pull out the copper wire from the tube. Ensure the tail end maintains a pigtail like shape and verify that the opposite end can be connected to a three-way stopcock. Shave the right cervical region of the anesthetized rat to expose the skin surface and disinfect the exposed area using a cotton swab soaked in rubbing alcohol.
Then using tissue scissors, make a two centimeter incision in the skin on the right side of the neck. With curved ophthalmic forceps bluntly dissect to expose the external jugular vein on the right side. Carefully free approximately one centimeter of the exposed external jugular vein and ligate the distal end of the vein using a five oh suture thread.
Tie a slip knot at the proximal end of the vein. Use a hemostat to clamp the suture thread at the distal end and gently pull it toward the head to tighten the blood vessel moderately. Now bend the prepared number seven needle at a 45 degree angle in the opposite direction of the needle tip.
Then fill the cardiac catheter, which is connected to the three-way stopcock with heparin sodium solution. After filling, close the three-way stopcock to prevent backflow. Insert the bent tip of the prepared number seven needle into the external jugular vein.
Gently lift the needle upward and insert the curved ophthalmic forceps along the needle track into the vein to open it up. Withdraw the needle carefully from the vein and insert the catheter into the vein through the gap created by the forceps. Next, carefully withdraw the curved ophthalmic forceps from the vein and untie the previously placed slip knot at the proximal end of the vein.
Push the catheter further into the vein. Then tie a new slip knot around the vein to secure the catheter. Ensure that the knot is not too tight and that there is no blood leakage while allowing smooth catheter movement.
Turn on the polygraph device and connect the pressure transducer to the polygraph. Flush the pressure transducer with normal saline to remove any air bubbles. Next, open the recording software on the connected computer.
Zero the pressure transducer by exposing it to atmospheric pressure and perform two point calibration using a mercury sphygmomanometer. In the software, set the filter type to low pass, the cutoff frequency to 40 hertz and the sampling rate to 1000 samples per second. Connect the three-way stopcock, which is attached to the catheter, to the pressure transducer.
Ensure there are no air bubbles in the three-way stopcock. Open and rotate the switch on the three-way stopcock to allow communication between the catheter and the pressure transducer and observe the venous waveform. Rotate the catheter while slowly pushing it forward.
If resistance is encountered, stop pushing and raise the pad made with a surgical blade, slightly withdraw the catheter, then rotate and push it forward again until a sudden loss of resistance is felt indicating entry into a larger space, at which point, the ventricular waveform appears. Push the catheter forward to reach the pulmonary artery. Observe the sensation of the catheter tip sliding along the heart wall during advancement.
Monitor the screen to identify the appearance of the pulmonary artery waveform. If an abnormal ventricular waveform appears, it may indicate that the catheter is having difficulty entering the pulmonary artery at this position. Withdraw the catheter slightly, rotate it and advance it again until the normal ventricular waveform appears, after which it should be easy to enter the pulmonary artery.
Two models of hypoxic pulmonary hypertension were established. one through the plateau environment simulation chamber, simulating an altitude of 5, 800 meters. And the other by chemically injecting one milliliter of 60%monocrotaline into the neck for 28 days.
In both models, the right ventricular systolic pressure and mean pulmonary arterial pressure were measured using this method and were significantly higher than those in the control group. Our protocol doesn't require a microscope, improves the process of and reduces the risks of puncturing the heart wall. This technology helps us measure pulmonary artery pressure in small animals more efficiently and accurately.
Our protocol provides support and framework for the reproducibility of studies related to pulmonary hypertension models.
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Overview
This article presents an optimized protocol for measuring pulmonary artery pressure (PAP) in rat models of pulmonary hypertension using right heart catheterization. The method addresses common challenges faced by beginners, such as catheter misplacement and procedural complications, and provides detailed steps for catheter preparation, surgical technique, and pressure measurement. The protocol is demonstrated in both hypoxic and monocrotaline-induced pulmonary hypertension models, offering a reproducible and efficient approach for researchers.
Key Study Components
Area of Science
- Cardiovascular physiology
- Animal models of disease
- Experimental surgery
Background
- Pulmonary artery pressure measurement is essential for diagnosing pulmonary hypertension.
- Right heart catheterization is the gold standard for PAP measurement but is technically challenging in small animals.
- Common issues include catheter misplacement into the inferior vena cava or right ventricle, prolonged procedure time, and risk of atrial puncture.
- Improved protocols can enhance accuracy and reproducibility in animal studies.
Purpose of Study
- To share an optimized, step-by-step protocol for right heart catheterization in rats.
- To reduce technical errors and procedural risks for beginners.
- To improve the efficiency and success rate of PAP measurement in pulmonary hypertension models.
Methods Used
- Preparation of a custom catheter using a PVC tube and copper wire to form a pigtail shape.
- Surgical exposure and cannulation of the right external jugular vein in anesthetized rats.
- Insertion and advancement of the catheter into the pulmonary artery, with real-time waveform monitoring.
- Calibration and use of a pressure transducer and polygraph system for accurate PAP recording.
- Application of the protocol in both hypoxic and monocrotaline-induced pulmonary hypertension rat models.
Main Results
- The optimized protocol enables efficient and accurate measurement of right ventricular systolic pressure and mean pulmonary arterial pressure.
- Both hypoxic and monocrotaline models showed significantly elevated PAP compared to controls.
- The method reduces the risk of heart wall puncture and does not require a microscope.
- The protocol supports reproducibility and reliability in pulmonary hypertension research.
Conclusions
- This improved right heart catheterization technique facilitates PAP measurement in small animal models.
- The protocol is accessible for beginners and minimizes common procedural errors.
- It provides a valuable framework for studies investigating pulmonary hypertension mechanisms and therapies.
