Primary prevention includes concerns about diving schedule and its procedures, the human – diver, and activities before-during-after the dive.

First of all, TRAINING. Although the need is obvious, repeating and emphasizing is useful for highlighting that its quality, duration and commitment are important too. There are lots of sayings about diving and one is “plan your dive, dive your plan”. Scheduling and diving a safe profile using a conservative model, will not reduce the joy and satisfaction of diving. For increased safety, a diver may choose to stay well within no-D limits of respective tables and be cautious in dives deeper than 30 meters where risk is statistically higher. Eliminating risk factors is important: deep prolonged dives, increased work during or immediately after the dive, repetitive dives. Multi-level dives are implicated in arteriolization of venous “silent” bubbles and subsequent DCS manifestation after relatively safe dives. The same with “reverse” profiles in repetitive dives. Also, spear-fishing after a SCUBA dive will result in DCS if not allowing sufficient time for elimination of inert gas absorbed during SCUBA. Having a “preventive” decompression stop (usually at 5 meters depth) in all dives confers extra safety. Diving should take place after a good night sleep, with no alcohol intake. Ample fluid intake before diving has been shown to result in reduced bubble formation after the dive. Since diving dehydrates the body, caution should be taken in periods of hot temperatures so as not to dive dehydrated. Hot bathing after diving is generally avoided. Flying and ascent to altitude after diving may produce DCS because of the unplanned further decompression. Especially for flying after diving (diving tourism needs), Divers Alert Network (DAN) has issued specific guidelines for the interval needed before flying after a dive. US Navy diving manual contains a dedicated table for the same purpose. Buddy diving increases safety and after prolonged abstention from diving, gradual return to previous diving performance (depth, duration) or initial dives with a diving school/an instructor is advised. Sense of security reduces air consumption and enhances pleasure. To put things right, autonomous diving is a very safe activity. According to DAN, there are 3-4 incidents for every 10.000 dives performed and most of them are mild.

With regard to the human – diver: A baseline medical examination is useful for every person. Requirement and physical standards may be different depending on the purpose of diving. Professional divers are normally required to have an annual assessment and respective certification of fitness to dive. Moreover, military divers have accurately defined standards and need to follow specific periodic reevaluation procedures. Concerning recreational diving, a required self-completed questionnaire plays the role of baseline assessment. For a “freshman” diver, however, medical examination if performed may be the first formal medical assessment of a person’s adulthood. Clinical assessment universally performed for fitness to dive certification (pulmonary, ENT/ear equalization etc) combined with person’s medical history, ensures that someone will not start diving at risk for himself or buddy divers. Some diseases that allow the person to have a normal life, may preclude from diving or dictate further assessment or treatment. Other symptom-free conditions that prohibit diving may be diagnosed as a result of such medical examination. On the other hand, conditions formerly regarded as contra-indications for diving, are nowadays considered (after many years of observation) to allow a person to dive safely with limitations and appropriate follow-up reevaluations. So, someone may be considered unfit for professional diving but fit for recreational diving with no health & safety compromise. Individualized advice according to person’s mental & physical characteristics that may influence his diving practice accordingly, is not uncommon and depends on physician’s experience.

DCS predisposing (risk) factors regarding the diver are: obesity (adipose tissue stores increased nitrogen quantities while slowly releasing them), age, previous history of DCS (although this may be associated with person’s risky behavior in general), dehydration, PFO and physical fitness. Sex as a risk factor (men are at increased risk) may be eliminated in the future as more women engage in diving activities and with similar profiles. Having said that, pregnancy is a contra-indication (temporary) for diving activities, as it exposes fetus at risk. In general, fitness and a good physical status are protecting factors. A diver should be free of any disease that affects mental status and alertness, anything that worsens by diving or anything that predisposes to DCS. Caution should be taken with drugs and diving. The critical question is the reason for someone taking medications and whether this condition predisposes to DCS or diving worsens this condition. Also, some medications may have adverse effects mimicking symptoms of DCS. A universally approved list of medications taken safely with diving, like the one for pilots, does not exist. What is important is the medication not to cause adverse effects/suspicious symptoms, and taking the medication for some time is helpful in distinguishing symptoms. Common analgesics are relatively safe and so are newer antihistamines, locally acting (crèmes), contraceptive pills and anticongestant sprays (not to be used for failure in equalizing, or just before the dive). Any recently added medication and those used chronically should be discussed separately.

Any change in ill-health status of a diver should be discussed with a specialist. After surgery or a hospital admission, sufficient period should be allowed for the body to recover, before diving again. There may be differences between individuals but the time of return to diving and/or a change of diving fitness should always be questioned. Also, recurrent conditions forcing a person to have multiple medical visits or treatments should alert for reevaluation of diving fitness or even question correlation with diving if connected in time.