Deep Sea Physiology PDF

DEEP SEA PHYSIOLOGY Adejumo O. Miracle Lead City University OUTLINE Introduction Effect of Sea Depth on the Volume of Gases Effect of high barometric pressure Nitrogen nacrosis Decompression sickness Scuba Deep sea physiology refers to the study of how the body resp...

DEEP SEA PHYSIOLOGY Adejumo O. Miracle Lead City University OUTLINE Introduction Effect of Sea Depth on the Volume of Gases Effect of high barometric pressure Nitrogen nacrosis Decompression sickness Scuba Deep sea physiology refers to the study of how the body responds to the pressure and gases found in the deep sea. It is important to understand the risk involved in deep sea diving. In areas of high altitude, there is problem with low barometric (atmospheric) pressure. But in deep sea, the problem is with high barometric pressure. When human descend beneath the sea, the pressure around them greatly increases as they go deeper. Air has to be supplied at a very high pressure to keep the lungs from collapsing and keep them inflated. In this situation, the blood in the lungs are exposed to very high alveolar gas pressure, which can cause some alterations in the body at certain limits. At the seal level, the barometric pressure is 760mmHg = 1atmosphere. Going below this level at every 10m (33 feet), the barometric pressure is increased by 1 atmosphere. This is due to the weight of the water and the air above it (Davis and Davis, 2021). So if a person who is 33 feet beneath the ocean surface is exposed to 2 atmospheres pressure, 1 atmosphere of pressure caused by the weight of the air above the water and the second atmosphere by the weight of the water itself. At 66 feet the pressure is 3 atmospheres, and increases as such the deeper the person goes  Effect of Sea Depth on the Volume of Gases The effect of sea depth on gases is the compression of gases to smaller and smaller volumes compared to the actual volume of the gases at sea level. Using the principle of Boyle’s law, which shows that the volume to which a given quantity of gas is compressed is inversely proportional to the pressure. At 33 feet beneath the sea, where the pressure is 2 atmospheres, the volume will be compressed to one-half the volume of the gas, and at 233 feet with 8 atmospheres it compressed to one-eighth of the volume (Patrician et al., 2021). This is important in diving physiology because increased pressure can collapse the air chambers of the diver’s body, especially the lungs, and often causes serious damage. Which necessitate the supply of gases to the diver at higher pressure  Effect of High Partial Pressures of Individual Gases on the Body Oxygen Toxicity Oxygen toxicity in deep sea physiology occurs when there is breathing of oxygen at a higher partial pressure than normal, which can result in the damage of cells and be a life threatening situation. Breathing oxygen at higher than normal partial pressure leads to hyperoxia and can cause oxygen toxicity or oxygen poisoning (Jing et al., 2024). Extended exposure to above-normal oxygen partial pressures or shorter exposures to very high partial pressures can cause oxidative damage to cell membranes leading to the collapse of the alveoli in the lungs. Oxygen toxicity is managed by reducing the exposure to increased oxygen levels (Cooper et al., 2023). NITROGEN NARCOSIS Narcosis is a state of unconsciousness, drowsiness or stupor produced by drugs. Nitrogen narcosis means narcotic effect produced by nitrogen at high pressure (Rocco et al., 2019). Nitrogen narcosis is common in deep sea divers, who breathe compressed air i.e. air under high pressure. It is to equalize the surrounding high pressure acting on thoracic wall and abdomen. Nitrogen is an inert gas that occupies about 78% of the atmospheric air, and has no significant effects on body functions at normal atmospheric pressure. But can cause various degree of narcosis at higher pressures as the person breathes pressurized air in deep sea. It produces a condition similar to alcoholic intoxication (Aravindhan et al., 2020). Due to compression by high barometric pressure in deep sea, nitrogen gets released from blood vessels and get dissolved in the fat present in various parts of the body due to its high solubility in fat. It is dissolved in the fatty substance in neuronal membrane and it has physical effect on altering ionic conductance through the membranes, leading to reduced neuronal excitability. It produces effects similar to that of anesthetic agents. SYMPTOMS First symptom starts appearing at a depth of 120 feet. The person becomes very jovial, careless and does not understand the seriousness of the conditions. At the depth of 150 to 200 feet, the person becomes drowsy At 200 to 250 feet depth, the person becomes extremely fatigued and weak. There is loss of concentration and judgment. Ability to perform skilled work or movements is also lost. Beyond the depth of 250 feet, the person becomes unconscious (Sharma et al., 2023). Measures to prevent nitrogen narcosis Nitrogen narcosis can be prevented by mixing helium with oxygen (Dreyer et al., 2024). Instead of nitrogen, helium is use to dilute oxygen during deep sea diving inside the oxygen tank. Although Helium has been shown to have a few side effects like dizziness and nausea, but they are less severe than that of nitrogen narcosis and the diver can adjust to it gradually. This is due to It has only about one fifth the narcotic effect of nitrogen Compared to nitrogen, only about one half as much volume of helium dissolves in the body tissues and the volume that dissolve diffuses out of the tissues during decompression several times faster than nitrogen, which reduces the intensity of decompression sickness. The low density of helium keeps the airway resistance for breathing at a minimum, compared to that of compressed nitrogen that can be extreme and make work of breathing beyond endurance.  It can also be prevented by limitation on the diving depths, have safe diving procedures like alcohol consumption should be avoided at least 24hrs before diving activities, and use of good and appropriate equipment. After divers return to depths of about 60 feet, symptoms of nitrogen narcosis completely disappear and the body returns to normal. But in situation where the divers loses consciousness, medical treatment should be sorted. DECOMPRESSION SICKNESS Decompression sickness is the disorder that occurs when a person returns rapidly to normal surroundings (atmospheric pressure) from the area of high atmospheric pressure like deep sea. It is also known as compressed air sickness, caisson disease, bends or diver’s palsy.  Mechanism of action in decompression sickness High barometric pressure at deep sea leads to compression of gases in the body. Compression reduces the volume of gases. Among the respiratory gases, oxygen is utilized by tissues. Carbon dioxide can be expired out. But, nitrogen, which is present in high concentration, is neither utilized nor expired. Instead it escapes from the blood vessels and gets dissolved in the fat of the tissues (Roberts, 2022) If a diver has been beneath the sea long enough that large amounts of nitrogen have dissolved in his or her body and the diver then suddenly comes back to the surface of the sea, significant quantities of nitrogen bubbles can develop in the body fluids either intracellularly or extracellularly and can cause minor or serious damage in almost any area of the body, depending on the number and sizes of bubbles formed ( Gottschalk, 2024). Due to sudden return to atmospheric pressure, the nitrogen is decompressed and escapes from the tissues at a faster rate. Being a gas, it forms bubbles while escaping rapidly. The bubbles travel through blood vessels and ducts. In many places, the bubbles obstruct the blood flow and produce air embolism. Underground tunnel workers who use the caissons (pressurized chambers) also develop decompression (caisson disease) sickness (Lance, 2024). Pressure in the chamber is increased to prevent the entry of water inside. Illustration of decompression sickness  SYMPTOMS Symptoms are due to the blocking of blood vessels by bubbles as a result of the escape of nitrogen from the tissues. Which can lead to tissue ischemia or sometimes tissue death. Other symptoms that can be experience are: Severe pain in tissues, particularly the joints, produced by nitrogen bubbles in the myelin sheath of sensory nerve fibers Temporary paralysis due to nitrogen bubbles in the myelin sheath of motor nerve fibers ( Williams, 2022) Muscle cramps associated with severe pain Obstruction of coronary arteries followed by coronary ischemia, caused by bubbles in the blood. Obstruction of blood vessels in brain and spinal cord which can lead to tissue damages. Dizziness, paralysis of muscle Chokes can occur due to massive numbers of microbubbles blocking the capillaries of the lungs, leading to shortness of breath. Often pulmonary edema and in rare cases death (Cibis, 2022) Fatigue Unconsciousness Prevention and treatment While returning to mean sea level, the ascent should be very slow with short stay at regular intervals. This allows nitrogen to come back to the blood, without forming bubbles and thus prevents the decompression sickness (Jayaraman et al., 2024). In a situation where decompression sickness occurs, the diver is placed into a pressurized tank, where he is recompressed to the amount of pressure experienced in deep sea and then the pressure is lower gradually back to normal atmospheric pressure using a recompression chamber (Mrakic- Sposta et al., 2024). It is also referred to as tank decompression. In some cases, hyperbaric oxygen therapy have been used in the treatment of decompression sickness (Moon & Mitchell, 2021). This is the treatment using 100% oxygen, this is the breathing of pure oxygen in a pressurize chamber. Physical symptoms of decompression A diver been treated in the recompression sickness chamber Hyperbaric Oxygen Therapy been carried out in a high pressure chamber  SCUBA SCUBA (Self-Contained Underwater Breathing Apparatus) is used by the deep sea divers and the underwater tunnel workers, to prevent the ill effects of increased barometric pressure in deep sea or tunnels. It consists of equipment such as air cylinders, valve system and a mask. Which makes it possible to breathe air or gas mixture without high pressure. The amount of air necessary during inspiration enters the mask and the expired air is expelled out of the mask as a result the valve system The instrument can only be use to remain in the sea or tunnel only for a short period. REFERENCES Aravindhan, D., & Kumar, M. J. S. (2020). Identification and Control Measure for Nitrogen Narcosis in Underwater Welding. International Journal for Research in Applied Science and Engineering Technology, 8(6), 1379-1382. Cibis, T. (2022). Decompression Modelling and Algorithm. In Engineering and Medicine in Extreme Environments (pp. 89-105). Cham: Springer International Publishing. Cooper, J. S., Phuyal, P., & Shah, N. (2023). Oxygen toxicity. In StatPearls [Internet]. StatPearls Publishing. Davis, H. E., & Davis, C. (2021). ALTITUDE ILLNESS AND DYSBARISMS. Emergency Medicine Secrets: Emergency Medicine Secrets E-Book, 342. Dreyer, S., Schneppendahl, J., Hoffmanns, M., Muth, T., & Schipke, J. D. (2024). Narcotic Nitrogen Effects Persist after a Simulated Deep Dive. Medicina, 60(7), 1083. Gottschalk, F. (2024). The effect of eccentric exercise on decompression strain (Doctoral dissertation, Karolinska Institutet). Jayaraman, M., Irwin, C., & Lee, E. (2024). 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