The LUCAS device is a battery-powered machine that performs chest compressions automatically during cardiac arrest, replacing the need for a rescuer to do CPR by hand. Its name stands for Lund University Cardiopulmonary Assist System, and it’s manufactured by Stryker Medical. The device is used by paramedics, emergency departments, and cardiac catheterization labs when consistent, uninterrupted chest compressions are critical.
How the Device Works
The LUCAS uses a mechanical piston fitted with a suction cup that sits directly on the patient’s chest. When activated, the piston pushes down to compress the chest, then the suction cup grips the chest wall and actively pulls it back up. This “active decompression” is a meaningful distinction from manual CPR, where the chest simply rebounds on its own between compressions. By pulling the chest back to its full resting position, the device helps draw more blood back into the heart between each compression, improving circulation.
The device compresses the chest at a rate of about 104 compressions per minute, which falls within the guideline range for effective CPR. Once positioned and started, it runs continuously without the fatigue, inconsistency, or interruptions that come with manual compressions.
Setup and Battery Life
Applying the LUCAS takes a brief pause in chest compressions. In a study of 32 cardiac arrest cases, the median pause to get the device onto the patient and running was about 32 seconds. After that, the device delivered compressions roughly 88% of the time it was in use, a metric known as compression fraction. For context, higher compression fractions are associated with better outcomes in cardiac arrest.
The current version, the LUCAS 3.1, runs on a rechargeable battery that lasts approximately 45 minutes of continuous operation. A full recharge takes less than two hours when charged inside the device, or up to four hours in an external charger. That 45-minute window covers the vast majority of resuscitation attempts, though crews can swap in a fresh battery if needed.
Who It Fits
The LUCAS is designed for adult patients only and is not indicated for children. It accommodates a chest width up to 17.7 inches and a sternum height (the distance from the back to the front of the chest when lying down) between 6.7 and 11.9 inches. Patient weight isn’t a limiting factor. If a patient is too small, the device will sound three quick alert tones when the suction cup is lowered. If the patient’s chest is too large for the upper part to lock into the back plate without already compressing the chest, the device can’t be used safely.
Why It Matters During Procedures
One of the most valuable applications of the LUCAS is during cardiac catheterization, the procedure where doctors thread a thin tube into the heart’s arteries to find and open blockages. If a patient’s heart stops during this procedure, or if the patient arrives in cardiac arrest and needs an emergency catheterization, manual CPR creates a serious logistical problem: someone has to stand at the table doing compressions, their hands and body blocking the X-ray imaging that guides the procedure.
The LUCAS solves this. Because the device is mechanical and sits low on the chest, doctors can see the coronary arteries on imaging while compressions continue uninterrupted. In one case series from a catheterization lab, the device maintained adequate blood pressure in 13 patients during cardiac arrest or dangerously low heart function, with compression times averaging 105 minutes and ranging up to four hours. Coronary imaging and intervention were possible in every case while the device kept running.
How It Compares to Manual CPR
The largest trial directly comparing the LUCAS to manual CPR was the LINC trial, a multicenter randomized study of out-of-hospital cardiac arrest. The results were essentially a tie. Survival at four hours was 23.6% with the LUCAS and 23.7% with manual CPR. Survival to hospital discharge with good neurological function was 8.3% versus 7.8%, a difference that wasn’t statistically meaningful. Six-month survival with intact brain function was similarly close at 8.5% versus 7.6%.
These numbers might seem surprising for a sophisticated piece of technology. The takeaway isn’t that the LUCAS doesn’t work. It’s that in a controlled trial setting, where manual CPR is performed by well-trained rescuers following strict protocols, the device performs comparably. The real-world advantages show up in situations the trial couldn’t fully capture: long transport times in rural areas, resuscitations that last an hour or more, procedures where human hands physically can’t be on the chest, or scenes where limited personnel make sustained high-quality manual CPR impractical. Fatigue degrades the quality of manual compressions within minutes, while the LUCAS delivers the same force and depth on compression number 5,000 as it does on compression number one.
Where It’s Used
The LUCAS is found in ambulances, emergency departments, cardiac catheterization labs, and some helicopter air medical services. It’s particularly common in EMS systems that serve large geographic areas, where patients may need CPR during a lengthy transport. Some systems also deploy it during avalanche rescues or drowning recoveries, situations where prolonged resuscitation efforts are standard and manual CPR is physically unsustainable.
The device is FDA-cleared for use on adult patients in acute circulatory arrest, defined as the absence of spontaneous breathing and pulse with loss of consciousness. It is not a home device or something available to the general public. Its operation requires training, and EMS agencies typically run crews through a structured certification before adding it to their equipment.