Basic Life Support (BLS)

If in your primary assessment you discover that the patient isn't breathing, and/or has no pulse, the patient requires basic life Support. For a no breathing patient, you'll begin rescue breath­ing. If the patient also has no pulse, you'll perform CPR for artificial circulation. Any trained person can perform BLS without sophisticated medical equipment, and it has proved effective in maintain­ing an restoring life in many instances. However, you need to keep in mind that BLS is time critical.

When either the respiratory or circulatory system fails, oxygen stops reaching the body. Most body tissues can endure a reasonable period without oxygen but the brain can’t. Without oxygen, you can expect brain damage in four to six minutes. After six minutes without oxygen, brain damage is very likely. After 10 minutes, the brain suffers irreversible brain damage (Note: One noted exception may be a person immersed in extremely cold water. There have been cold water drowning accidents in which the patients were revived after more than 30 minutes without appar­ent brain damage).

Ideally, you want to begin BLS as soon as you recognize the need for it, and continue it until the patient is under professional emergency medical care. The realities of diving mean you can't always, (for example, effective CPR isn’t possible in the water - more about this is Chapter Six), but when a diver needs BLS, you want to begin BLS as soon as possible.