A cross clamp is a surgical instrument used to isolate the heart from the rest of the body's circulation during procedures on and around the heart. This results in a state known as cardioplegia, where the heart is not beating. In surgeries where the heart needs to be stopped, there are a number of risks, addressed by keeping the surgery as short as possible and taking protective steps such as chilling the heart to prevent damages associated with ischemia, where no blood is flowing through the organ. The alternative is a beating heart surgery, where the heart is allowed to beat freely and the surgeon works around it, but this option may not always be available.
Also known as an aortic cross clamp, this instrument is designed to be clamped down on the aorta to stop the flow of blood from the heart. Depending on the type of procedure, it may be left on continuously or the surgeon may use a technique called cross clamp fibrillation, where the clamp is periodically relaxed to allow the heart to reperfuse with blood. The surgical team monitors the patient throughout the surgery for signs of distress, and a cardiothoracic surgeon usually supervises.
There are some risks with the cross clamp. One is damage caused by ischemia, as tissues will die when deprived of oxygen long enough. Chilling the heart first reduces this risk, as the cold slows the rate of damage. Patients can also develop clots, potentially leading to a blockage of a vein or a stroke. In addition, sometimes releasing the clamp causes a reperfusion injury, and the removal of the clamp must be conducted with care.
Like other surgical instruments, the cross clamp is made from surgical-grade steel, a steel product specifically developed for use in operating rooms. This steel is strong, with some flexibility to prevent it from snapping under stress. It resists rust and can also endure very hot and cold temperatures, allowing people to use it in chilled procedures, as well as autoclaving it between surgeries.
After surgery, all of the tools are counted to confirm that everything used in the surgery has been accounted for. They are soaked in antiseptic solution and scrubbed before being packaged for an autoclave, a device that uses high heat to kill infectious organisms. Autoclaved medical instruments are safe for use in new patients, and tools may remain in use for years or even decades.