Diving injury and illness
Diving and snorkelling activities expose participants to a wide range of potential hazards which can lead to a range of injuries and illness.
Drowning
Water cannot be breathed in and inhaling it could lead to drowning syndromes resulting in injury or death. To reduce these risks, make sure workers are medically fit, have appropriate equipment, are properly trained and experienced and are not left behind.
Drowning may result whenever a person becomes incapacitated in-water (e.g. through fatigue, panic or another injury). PCBUs must ensure that divers and snorkellers are supervised and also have efficient and effective systems, personnel and equipment for rescue, first aid and evacuation.
Decompression illness
Decompression illness can result when excessive amounts of nitrogen in the body start to form bubbles in blood vessels and tissues as the diver ascends. The bubbles can cause tissue damage and block blood vessels, obstructing blood flow to vital organs.
Decompression illness can arise after any diving, even when diving has been carried out within the limits of decompression models. If a diver displays symptoms, appropriate first aid should be provided and medical advice sought.
Barotrauma
Barotrauma is injury brought about by pressure differences causing changes in volume in air spaces in the body. Examples of air spaces at risk of barotrauma include the ears, sinuses, lungs and the face-mask cavity.
During descent external pressure may become greater than the pressure within air spaces. For example, if a diver cannot or does not equalise the ears during descent, then a perforated eardrum can result.
When a diver ascends, the external pressure may become less than the pressure within an air space. If the diver does not exhale on ascent and/or makes a rapid ascent, their lungs will expand as the volume of gas increases. This can result in lung tissue being overstretched and tearing with gas escaping into surrounding tissues or the bloodstream. If the gas enters the bloodstream, it may lead to arterial gas embolism which can result in death, stroke or other neurological conditions.
As the greatest pressure changes occur near the surface, the diver is most at risk of barotrauma within the first 10 metres.
Contaminated air
Breathing gases for divers must not be contaminated. Even small amounts of contamination can affect divers, and the effects of most contaminants increase with the depth of the dive. Possible contaminants include carbon monoxide and oil. Contaminants can cause a range of injuries and illness including, convulsions, loss of consciousness and death.
Compressor systems must be correctly designed, installed and operated to minimise risks of contamination. Gases must be regularly tested to monitor contaminant levels and a current test certificate (valid for three months) should be available for each compressor.
Air is primarily composed of oxygen and nitrogen. Even these gases can have serious effects on a diver's health when breathed at depth See below for more information about the effects of nitrogen.
Nitrogen narcosis
Nitrogen narcosis can result from breathing nitrogen under pressure. It acts like a drug and affects individuals differently. Nitrogen narcosis affects reasoning, judgement, memory, perception, concentration and coordination. It may lead to over confidence, anxiety or panic. Survival instincts and responses may be suppressed. If the dive is uneventful, the narcotic effects of nitrogen narcosis may not be evident. A diver failing to follow instructions or the dive plan, or being inattentive to buoyancy, air supply or buddy signals may be suffering from nitrogen narcosis.
Diving on air at or beyond 30 metres significantly increases the risk of nitrogen narcosis. Nitrogen narcosis can develop when diving in shallower depths, but is less likely to be evident, that is, a diver may not be aware that he or she is affected by nitrogen narcosis and/or it may not be evident to an observer. Safe diving beyond 30 metres requires an awareness of the increasing risk of this condition and its symptoms, and the practices required to reduce the symptoms and the associated likelihood of an accident. Nitrogen narcosis is directly related to diving at depths and diminishes as a diver ascends to shallower water. If a diver begins to be affected by nitrogen narcosis, then immediate ascent to shallower depths, taking into account decompression requirements, is required.
Factors known to increase the effects of nitrogen narcosis include:
- fatigue or heavy work
- anxiety, inexperience or apprehension
- the diver feeling cold
- poor visibility
- carbon dioxide excess
- recent alcohol intake or use of sedative drugs including sea sickness medications or marijuana.
Panic
Studies have implicated panic as a contributor to many diving /snorkelling deaths. As panic develops, anxiety increases and a person diving /snorkelling reduces his or her capacity to think rationally and may focus on only one act or goal while forgetting about other important requirements. For instance, a panicky diver might focus on reaching the surface but forget to exhale during ascent.
Factors which can play a role in the development of panic include:
- equipment problems such as low air and ill-fitting equipment
- environmental hazards such as cold water, deep diving, marine animals and poor visibility
- personal factors such as fatigue, medical or physical unfitness, seasickness, alcohol intake, inexperience, excessive general anxiety, phobias, diving accidents, dizziness or disorientation
- inadequate instruction and training of person diving-snorkelling/snorkelling.
Effective explanation and training in relation to all relevant aspects of diving can help minimise the likelihood of panic. Additionally, it is important for a person diving /snorkelling to know his or her limitations and to stay within these.
While the person displaying anxiety and lack of confidence may be readily noticed and can be more thoroughly trained, more carefully monitored, given more assistance or advised not to engage in diving-snorkelling, also at risk is the overconfident person diving /snorkelling who is out of touch with or concealing his or her real capabilities and concerns.
Immersion Pulmonary Oedema (IPO)
IPO is a condition where the lungs fill with fluid, the person struggles to breathe and consequently the body struggles to get enough oxygen. It is caused by changes in hydrostatic pressure and breathing resistance when a body is immersed in-water. People who suffer high blood pressure (hypertension) and other cardiac conditions are particularly susceptible to IPO.
Symptoms
The onset of IPO can be sudden and is usually precipitated by a feeling of breathlessness. It is critical for dive operators and safety personnel to recognise the early indicators to respond quickly and effectively. Symptoms can include:
- breathing difficulties, such as rapid or uneven breathing in both divers and snorkellers
- signalling a problem with their regulator or ’out of air’ and rejecting an alternate air source
- snorkellers may move upright in the water and remove their snorkel from their mouths
- uncontrolled coughing often starting as a small tickle in the back of the throat but is persistent and can’t be resolved
- coughing up bloodstained frothy sputum
- a tightness in the chest and crackling and wheezing sounds may be heard from their lungs
- reduced oxygen will often cause cyanosis (blueness of lips and tongue), confusion and people suffering IPO may appear to be intoxicated or function abnormally.
IPO can be fatal and needs to be managed promptly. Early recognition and prompt management are essential to improve outcomes and reduce the risk of serious complications.
Action required
The primary treatment is to remove the person from the water and place them on oxygen as quickly as possible to reverse the effects caused by immersion and increase oxygenation.
If conscious, they should be kept in a comfortable position, often sitting or semi-reclined to assist their breathing. The person should be provided with high concentration oxygen as soon as possible. This should be delivered by constant flow rather than a demand valve to reduce breathing resistance.
IPO sufferers often improve when provided with oxygen. An individual who has experienced IPO should be taken to hospital for further assessment and treatment.