Overview of Arterial Pressure Monitoring
Keeping track of a patient’s physical status is crucial when they are in the hospital. This is especially important for patients who are very ill or for those undergoing surgery, as they are at a higher risk for health complications. There are two ways doctors can monitor a patient’s vitals, either by regular checkups, which are non-invasive but only offer limited information, or through continuous, invasive monitoring measures.
One common method is through checking blood pressure directly from an artery. This is done by inserting a small tube, called a cannula, into an artery. Each heartbeat creates a force that moves this flow inside the catheter. This motion is then transferred through a firm, fluid-filled tube to a device that turns this movement into electrical signals.
These signals are then sent to a monitor that presents a detailed visualization of the patient’s heartbeat and shows the numerical pressures of different parts of the cardiovascular system (the heart and blood vessels). This continuous stream of information allows the medical team to understand the patient’s heart health and helps them decide on the right course of treatment.
Anatomy and Physiology of Arterial Pressure Monitoring
The radial artery, located in the wrist, is the most often used spot for a procedure called arterial cannulation because it’s easy to reach. Cannulation is when a small, flexible tube is inserted into an artery, usually to draw blood or administer medication. Other locations that can be used for this procedure include the brachial artery (in the upper arm), the femoral artery (in the thigh), and the dorsalis pedis artery (on the top of the foot).
Why do People Need Arterial Pressure Monitoring
An arterial line is a thin tube that doctors insert into an artery. It helps monitor the patient’s blood pressure in real-time and collect blood samples for tests. It’s typically used under certain conditions which are:
The first group of people who might need an arterial line are seriously ill patients in intensive care who need constant monitoring of their blood pressure because this can change rapidly. Timely care is crucial for these patients, so doctors use the arterial line to watch for changes in their blood pressure and act immediately if needed.
Secondly, patients who are receiving medicine that affects their blood pressure, known as vasoactive medications, also benefit from an arterial line. It allows doctors to closely monitor their blood pressure and adjust the dosage of the medicine as required, ensuring it’s at the right level for the patient.
Patients undergoing surgery could also benefit from an arterial line, especially if they are at a higher risk of complications due to other health conditions such as heart or lung disease, or anemia. This includes surgeries involving the brain, heart, and lungs, or any procedure where there may be a lot of blood loss.
Finally, an arterial line can be very beneficial for patients who need frequent blood tests. For example, patients who need help with breathing and are connected to a ventilation machine would need their blood tested often to adjust the ventilator settings. The testing helps monitor different aspects of the patient’s blood such as its oxygen and electrolyte levels, the volume of red blood cells, and how the body responds to fluid and calcium delivery. In these cases, the arterial line allows doctors to easily draw blood for testing without repeatedly pricking the patient, thereby reducing the discomfort and lowering the risk of infection.
In essence, an arterial line is a medical tool that allows doctors to monitor the patient’s blood pressure in real time and perform blood tests easily. This helps in providing better and timely care to the patient, ultimately enhancing their recovery process.
When a Person Should Avoid Arterial Pressure Monitoring
Checking the pressure of the blood flowing in arteries can provide us with important information about a patient’s health. But this process, called arterial cannulation, doesn’t need to be done on all patients, such as everyone in the ICU or going into surgery. For some people, there are specific reasons it isn’t safe or beneficial. These reasons include:
If they have an infection where the cannulation would be done, it could be risky. If their body is set up differently than usual so blood circulation could be disrupted during the procedure, it’s best not to proceed. If they have issues with blood flow in peripheral arteries – the blood vessels farthest from the heart – or have a certain type of artery disease, it’s also not advisable.
Moreover, patients who have blood disorders that affect clotting or are taking medications that prevent blood clotting may need to be considered carefully before performing this procedure. Though these aren’t absolute reasons not to do it, they need to be reviewed responsibly.
Possible Complications of Arterial Pressure Monitoring
Messuring blood pressure by inserting a tiny tube into an artery (a process known as arterial cannulation) can sometimes result in complications. Possible issues include:
- An infection where the tube was inserted
- Challenges in getting blood to parts of the body because of a lacking secondary blood supply
- The creation of a hematoma, which is a swelling of clotted blood
- The creation of an arteriovenous (AV) fistula, a connection between an artery and a vein
- Narrowing of the blood vessel where the tube was inserted
- Loss of blood
There’s an ongoing discussion regarding the use of the brachial artery (the major blood vessel of the upper arm) for catheterization. This is because it is close to the median nerve and could potentially be damaged during the procedure. There’s also a risk of blood clot formation and a lack of secondary blood vessels to divert blood flow if something goes wrong; this could lead to inadequate blood supply to the hand. Despite these potential risks, this rarely leads to serious problems. Also, this method has a lower chance of causing infection in comparison to inserting a tube into the femoral artery (found in the thigh).
Brachial artery catheterization is typically more reliable in patients undergoing heart surgery, especially after procedures that involve temporarily stopping the heart, like bypass surgery. So, given the low risks, using the brachial artery for catheterization is considered a good option.
What Else Should I Know About Arterial Pressure Monitoring?
Arterial pressure monitors are devices used to continuously track the blood pressure in your arteries. They provide important data on your body’s circulation, which is crucial for doctors to make timely decisions and provide the right care if you’re in critical condition. They can interpret your heart health by analyzing the pattern of your arterial pressure.
Understanding this pattern can be broken down into two parts related to your heartbeat: the systole and diastole. When your heart is in the systole phase, a part of your heart known as the aortic valve opens and quickly sends blood into an artery called the aorta. This event causes a rising and then falling pattern on the monitor’s display.
The completion of the systole phase marks the beginning of the diastole phase, signified by the closing of the aortic valve. An identifying mark, known as the dicrotic notch, will show up on the monitor’s graph during the diastole phase due to this valve’s closure. The rest of the dropping pattern represents the blood continuing to flow into the arteries.
If your heart rhythm isn’t regular or if you have issues with your heart valves, this can lead to an unusual pattern on the arterial pressure monitor. This information can greatly help your doctor to understand your heart health better and provide the necessary treatment.
