Assessing the Situation and Immediate Actions
You spot an unconscious diver. The first and most critical action is to get them to the surface immediately while ensuring their airway is protected. Time is of the essence; brain damage can begin after only a few minutes without oxygen. As you ascend, you must maintain an open airway for the diver and perform a controlled, safe ascent, typically not faster than 30 feet (9 meters) per minute to avoid decompression sickness for yourself, but the immediate threat of drowning takes precedence. Upon reaching the surface, your priority shifts to establishing positive buoyancy for both of you and initiating rescue breathing in the water, using their own air supply. This is a fundamental skill taught in rescue diver courses.
The primary goal is to deliver life-saving oxygen to their lungs as quickly as possible. Their own portable scuba tank is the best tool for this. It contains 100% breathable air (or a Nitrox mix), which is far superior to attempting mouth-to-mouth resuscitation in the water, which is difficult and inefficient. The regulator attached to their tank is designed to deliver air on demand, even if the diver is not breathing actively.
In-Water Rescue Breathing Using the Diver’s Tank
Once at the surface and positively buoyant, follow these steps meticulously. This procedure assumes you have successfully deployed the diver’s buoyancy compensator (BCD).
- Position the Diver and Yourself: Roll the diver onto their back, supporting their head and neck to keep the airway straight and above the waterline. You should be at their side, in a stable position, likely using your own BCD for buoyancy.
- Locate and Clear the Regulator: Find the primary second-stage regulator (the one they were breathing from). Purge it by pressing the purge button to ensure it’s clear of water. If the regulator has a switch for changing the breathing resistance, ensure it is in the normal position.
- Open the Airway and Seal the Mask: Tilt the diver’s head back slightly using one hand on their forehead (the head-tilt/chin-lift maneuver). With your other hand, hold the regulator firmly over their mouth, using the diver’s own mask to help create a seal. Place the mask over their nose and mouth, with the regulator mouthpiece inside. This technique helps create a much better seal than just the regulator alone.
- Initiate Rescue Breathing: Press the purge button on the regulator in short, one-second bursts. Watch the diver’s chest. You should see it rise as you purge air into their lungs. Allow the chest to fall naturally between breaths.
- Breathing Rate: Deliver one breath every 5 seconds. This is a slower rate than standard CPR because you are providing a full lungful of air with each purge. Continue this without interruption while you signal for help and begin towing the diver to safety (a boat or shore).
The effectiveness of this technique hinges on the regulator’s design. Modern regulators have very high flow rates, often exceeding 2000 liters per minute, which means they can deliver a substantial volume of air instantly when purged. This is far more air than you could exhale during mouth-to-mouth. The following table compares the two methods:
| Factor | Rescue Breathing via Regulator Purge | In-Water Mouth-to-Mouth |
|---|---|---|
| Oxygen Source | Diver’s tank (21% O2 or higher) | Rescuer’s exhaled breath (~16% O2) |
| Air Volume Delivered | High (dictated by regulator flow rate) | Low (limited by rescuer’s lung capacity) |
| Efficacy of Seal | Good (especially when using the mask to seal) | Poor (difficult in water, high risk of water ingress) |
| Rescuer Fatigue | Low (simple button press) | High (physically demanding) |
Getting the Diver to Safety and Advanced Care
Your towing effort should be efficient, conserving your energy. Use a modified finning technique, such as a modified scissor kick, and tow the diver from their tank valve or BCD harness. Keep their airway clear and continue rescue breathing throughout the tow. The moment you reach a boat or solid platform, the situation escalates. You need to get the diver out of the water as quickly as possible. This may require assistance. Once on a stable surface, you must begin a full assessment.
Check for breathing and a pulse simultaneously for no more than 10 seconds. If there is no normal breathing and no pulse, you must immediately begin full CPR. The sequence is 30 chest compressions followed by 2 rescue breaths. You can now switch to using a pocket mask for a more hygienic and effective seal for the breaths, but continuing to use the diver’s tank via the regulator purge is still a highly effective method, especially if a pocket mask isn’t immediately available. The compressions are critical; they need to be hard and fast, at a rate of 100-120 per minute, with a depth of at least 2 inches (5 cm) for an adult.
Equipment Considerations and Preparedness
The success of this rescue is heavily dependent on the equipment’s readiness and your familiarity with it. A well-maintained regulator is non-negotiable. It should be serviced annually or after every 100 dives, whichever comes first. A malfunctioning regulator with a stuck purge valve could over-inflate the diver’s lungs, causing injury, or a leaky diaphragm might not deliver enough air. The tank itself must be in test; visual inspections occur annually, and hydrostatic testing is typically every 5 years. A small, compact tank can be just as effective for this rescue purpose as a large one, as the air delivery method is the same. The key factors are the regulator’s performance and the rescuer’s skill.
Beyond the tank, every diver should carry a surface marker buoy (SMB) and an audible signaling device, like a whistle or a Dive Alert. These are invaluable for attracting attention during a rescue. A cutting tool is also essential for dealing with entanglement. This highlights the importance of a well-configured gear setup. For example, the second-stage regulator should be on a bungee necklace to prevent it from dangling, and the alternate air source (octopus) should be readily accessible on a bright yellow hose, typically in the triangle between the chin and the chest.
Ultimately, the ability to perform this rescue confidently comes from proper training. A Rescue Diver certification course, offered by agencies like PADI, SSI, or RAID, provides the hands-on practice necessary to manage the stress and execute the steps correctly. These courses cover not only in-water rescue breathing but also panic management, equipment failure scenarios, and effective emergency response planning. Practicing these skills in a controlled environment is the only way to build the muscle memory required to act effectively during a real emergency.