Medical Catheter Sensors

Minimally invasive surgeries greatly reduce cost, recovery time, incision size and many other benefits.  Small flexible tubes, called catheters, can access many parts of the body by traveling through arteries. For successful surgeries, monitoring devices must provide data to the doctor. Medical sensors provide data but must be small enough to fit in the catheter and leave room for other sensors and surgical tools. To improve surgeries and control costs, surgeons use a host of sensors to provide real-time feedback. To verify location, track temperature, and more, medical sensors are becoming increasingly compact, allowing more surgical tools and technology to fit within catheters and drive minimally invasive surgeries.

The ability to use small incisions and arteries to access difficult to reach parts of the body can reduce recovery time, have fewer reported complications, and many other benefits. However, minimally invasive surgical procedures require technology to provide accurate data to verify each step is done properly. For example, an arrhythmia occurs when the heart beats at an irregular or abormal rate. Doctors may perform an ablation catheter procedure for treatment. Using multiple catheters and small flexible tubes, doctors can access the heart through an artery. Ablation catheter procedures use different thermal techniques such as radio frequencies, laser, or cryoablation to create an ablation line or scar tissue on the heart. These small scars help block abnormal electric signals from affecting the patient’s heartbeat. Traveling through arteries to perform work inside the heart demands accurate and reliable technology in the smallest packages.

A pressure catheter is an example of how sensors are helping to deliver constant patient monitoring in an expanding minimally invasive procedure industry.  Pressure catheters can monitor multiple parts of the body including spines, tumor, and airways. In monitoring arterial or ventricular blood pressure monitoring, the pressure catheter uses micro-sensors for accurate, constant monitoring of vital signs.  Miniaturization advancements in medical sensor technology, has made these types of procedures much less invasive than in the past. Today, a catheter can travel to the heart through an artery and inflate a balloon to help clear blocked arteries. The multi-functional balloon catheters need precise monitoring from different sensors to perform and verify the success of such complex surgeries. 

A standard thermo-dilution catheter is capable of monitoring cardiac output (CO), pulmonary artery occlusion pressure (PAOP), and central venous pressure (CVP). Monitoring this data requires compact temperature and pressure sensors. For transpulmonary and PA thermodilution, CO is determined by injecting a cold saline solution into the bloodstream that mixes with the blood. Using data from the temperature sensor in the tip of the catheter combined with the known starting temperature of the solution can determine the CO. However, due to the nature of these methods, the CO result is intermittent. Other methods use the systolic portion of the arterial pressure and aortic impedance that offers a continuous display of CO. Whichever method is used, one driver remains constant - compact, accurate, and reliable sensor technology.