In another document titled "An Evaluation of the NUI Compact Chest Compression Device (NCCD), a Mechanical CPR Device Suitable for Use in the Saturation Diving Environment", which is, in fact, the continuation of the above one, the same team of scientists has compared the efficiency of the Compact Chest Compression Device (NCCD), a CPR device developed by the Norwegian Underwater Institute (NUI), with classical CPR techniques performed by experts. In addition to providing guidelines for implementing this device, the authors conclude that it is efficient. We can, therefore, suggest that such devices should be systematically included in the bell's medical kit. The NUI Compact Chest Compression Device (NCCD) is not the first cardiac resuscitation device designed for hyperbaric conditions. For example, we can refer to the excellent study entitled "Report on tests of Zoll automatic external defibrillator function in hyperbaric heliox conditions" by the Helix company, published on the Diving Medical Advisory Committee (DMAC) website (https://www.dmac- diving.org/guidance/). An automated external defibrillator (AED) is a portable electronic device that can automatically diagnose and treat a patient's potentially life-threatening cardiac arrhythmias of ventricular fibrillation and ventricular tachycardia by defibrillating the heart. However, despite the advantages of these devices, they have the inconvenience of being powered by batteries, which, in addition to the precautions to be implemented with lithium batteries stored in a hyperbaric environment, may have an availability problem, resulting in the preferred solution proposed that consists of having the device outside the chamber with only the electrodes inside the chamber, resulting in the device being operated by an operator outside the chamber on the instructions of the diver medic. This solution would be challenging to use with a diving bell for many technical reasons.  Unlike defibrillators, the Compact Chest Compression Device (NCCD) is powered by compressed gas at a pressure of 10 bar above the ambient pressure of the bell. Finding a gas supply source in the bell is not a problem, so the availability problem is solved. The manufacturer recommends not using mixtures with more than 22% PPO2 (NORSOK standard limit is 22%) and continuously monitoring the PPO2 and ambient pressure of the bell, which any trained supervisor is accustomed to doing at all times. The machine consists of the following parts, stored in a reinforced sealed box: • The compression unit, which includes the piston house, the bottom plate, and the piston foot that transmit the movements of the piston (see #1) • The hand control unit that allows starting and stopping the compressions (see #2). • The supply hose connecting the hand control unit to the compression unit (see #3). • The supply hose of the hand control unit equipped with a quick connector (see #4). • A Velcro strap with adjustment markings (see #5) to secure the compression unit in place. • An adjustable support strap designed to prevent the compression unit from sliding down, ensuring the system provides adequate compressions when the patient is in a vertical position. It is equipped with carabiner hooks for attachment to the slots on the compression unit's plate (see #6). • An extension hose of 1.5 m (see #7) and scissors that are strong enough to cut fabrics (see #8) are also provided.