Hyperbaric medicine is a medical field dedicated to studying the physiological risks associated with using self-contained underwater breathing apparatus (SCUBA) during diving. The majority of these risks arise due to the escalation in atmospheric pressure as depth increases. For instance, at a depth of 10 meters, the total pressure is twice that of the surface pressure, and at 30 meters, it becomes four times the surface pressure.
While descending, divers need to introduce gas into their middle-ear cavities and facial sinuses to safeguard against harm caused by increasing pressure. This phenomenon of rising pressure is akin to what passengers on airplanes undergo during the descent and subsequent repressurization.
No matter the depth they reach, divers must be provided with breathing mixtures adjusted to match the external water pressure. While ascending, the gas in their lungs expands and can damage lung tissues if the diver becomes anxious and unintentionally holds their breath. This leads to a critical condition called pulmonary barotrauma, also known as burst lung. Symptoms can encompass coughing up blood, difficulty urinating, breathing challenges, and even loss of consciousness.
Recreational divers use compressed air for breathing, primarily composed of nitrogen and oxygen. These gases are benign when encountered at normal surface pressures but can turn harmful at higher pressures. Nitrogen can adversely affect the nervous system when inhaled at greater depths, resulting in slowed mental faculties and other symptoms resembling alcohol intoxication, a condition referred to as nitrogen narcosis. Oxygen also becomes hazardous under increased pressure, potentially leading to convulsions or damage to the lungs when breathed at such conditions.
To achieve greater depths while minimizing the risks of nitrogen and oxygen toxicity, experienced divers utilize gas blends different from regular air. A common blend includes helium, along with minimal quantities of oxygen and nitrogen; helium is comparatively less toxic.
During dives, divers retain surplus amounts of inert gases, such as nitrogen when breathing air, within their bodily tissues. If pressure is rapidly reduced during ascent, particularly if the diver has spent an extended period at depth accumulating a substantial gas load, these gases may no longer remain dissolved in the body, leading to the formation of bubbles in tissues and bloodstream. This occurrence results in decompression sickness.
Further risks involve hypothermia, which arises from exposure to cold water, as well as potential bites or stings from marine creatures. Furthermore, there is a danger of drowning.
Individuals considering starting scuba diving should undergo a medical examination and receive training from an accredited diving school beforehand.
Pressure-related incidents like burst lungs and decompression sickness are managed through the use of a specialized pressure chamber, where the diver is recompressed. This facilitates the reabsorption of any gas bubbles or pockets in the blood or tissues. Subsequently, a gradual reduction of pressure is initiated.