To decompress and off gas excess inert gas correctly and efficiently is imperative so as to avoid decompression illness (DCI). By following the staged decompression procedures outlined here, your ability to off gas sufficiently increases and makes decompression diving safer. Remember, however, that no matter how stringent you follow decompression guidelines and safety factors, you can still be susceptible to getting DCI on any dive.
· Make sure you and your team hydrates well prior to the dive. Start hydration at least 12 hours prior to the dive and make sure to hydrate after the dive.
· Plan your dive appropriately with the right gases for your bottom mix and your decompression mixes. Use gases that limit inert gas buildup and allow for the best and most efficient off gassing during decompression.
· Locate, set up, and mark a point that provides the entire dive team a suitable place to decompress. This might include a down line when wreck diving or specific location in a cave or cavern when cave diving. You should be able to rest comfortably with some type of handhold so that your chest remains at a constant depth. You don’t want to be moving up and down. Sometimes knowing exactly where you’re going to decompress at each stop depth is not practical, but knowing the requirements you need to follow when at a stop depth can help you decide on a spot during the dive.
· When placing decompression cylinders, place them one stop depth deeper than the deepest stop planned for that gas. For example, if you’re using an EAN50 for decompression, the maximum operating depth (MOD) for that mix is 70 feet (21 m). Place your EAN50 cylinder at 80 feet (24 m); one stop depth deeper than it is to be used.
· When executing the dive, all team members should monitor dive time, depth, and tank pressure. If there is a discrepancy in one of these, always error on the side of the most conservative reading.
· Execute the dive with good team coordination and avoid unnecessary exertion on the dive. Also, make sure the team is using the appropriate exposure suits for the type of diving you’re doing. If you start the dive cold or get chilled during the dive, this increases your susceptibility of getting DCI. Excess exertion also contributes to a carbon dioxide buildup, which affects decompression.
· Plan the first part of your dive to be the deepest part of your dive. Sometimes this may not be possible, such as when cave diving. When repetitive diving, do your deepest dives at the beginning of your diving day.
· When returning form a dive to your first decompression stop, pause at the deepest level of your dive for a minute or so to allow any carbon dioxide (CO2) buildup from exertion on the dive to be eliminated or reduced. CO2 is known to attach itself to any bubbles that may have formed, which could bring the bubble size to critical mass and cause DCI.
· Ascend at a rate appropriate for the dive tables or dive computer you’re using. Make sure that you do not ascend too quickly. This can cause inert gas to come out of solution quickly causing DCI.
· When you get to a decompression stop and are switching to a new gas, spend at least three to five minutes breathing this gas before moving up to your next stop even if the stop time is less. It takes the human body approximately this amount of time to completely circulate the gas throughout your body. To be affective, the gas must have sufficient time to circulate around your body and take affect.
· When planning your decompression schedule, plan conservatively. Don’t “push” the tables or computer or think that you’re decompression ability is something that it’s not.
· At each stop depth, make sure that you breathe normally. Don’t alter your breathing just because you’re decompressing.
· Don’t exert yourself while on decompression. You don’t want to cause an increased amount of CO2 that could affect your ability to decompress.
· Perform a small amount of movement while decompressing. Easily exercise your arms and legs by moving them around from time to time.
· Make sure that you stay at the appropriate stop depth. Don’t swim up or down during decompression.
· After surfacing, don’t overexert yourself. Just because you’re on the surface, don’t assume that decompression is over. You’re body still has a certain amount of excess inert gas that must be off gassed. This takes time.