Deep Sea Diving Deep Sea Diving Hyperbaric Condition
Deep Sea Diving
Deep Sea Diving & Hyperbaric Condition • Atmosph = 760 mm. Hg • Deep into sea, at every 33 feet pressure rises by 1 atmosphere • Vol. of air compressed & pressure increased along with depth • Deep sea diver – breath high pressure air
PATHOPHYSIOLOGY PARAMETER DEEP SEA HIGH DIVING ALTITUDE • Barometric Pressure • Volume of Gases • Intra-thoracic Pressure • Intra-alveolar Pressure [Compression] [Expansion]
Pressure Related Problems (direct) • Descent (squeezes) – – – – Ears Sinuses Mask Thoracic Teeth Stomach/Intestines Suit • Ascent (expansion) – Air embolism – Pneumothorax – Mediastinal Emphysema – Subcutaneous Emphysema
Pressure Related Problems (indirect) • Decompression sickness – Nitrogen partial pressures – Solubility • Nitrogen narcosis • Oxygen toxicity
1% r he Ot 21% O 2 78% N 2 760 mm Hg 47 95 190 380 523 760 ------- mm/Hg Partial Pressure (Dalton’s Law)
Nitrogen Narcosis at High Nitrogen Pressure • About 4/5 th of air – nitrogen • At sea level no ill effect of nitrogen but at high pressure (deep in sea) varying degree of narcosis • First symptom of narcosis joviality, at 120 feet deep, after remaining for some time • At 150 – 200 feet – Drowsy • At 200 – 250 feet – Strength wanes, • Beyond 250 feet – person can’t move
• Nitrogen narcosis like alcohol intoxication -impaired memory, impaired thought making • Nitrogen mech. Same as that of gas anaesthesia
Nitrogen narcosis Nitrogen Narcosis “Rapture of the Deep” - “Martini’s Law” SURFACE Thinking and Judgment POTENTIALLY Affected 75 -100 m 250 -325 ft Communication, Motor and Mental Tasks IMPAIRED Symptoms and Effects on Individual Diver Vary With Depth and Exposure. 150 -175 m 500 -575 ft NOT IN CONTROL 200 m+
• Nitrogen 5 time move soluble in fat than in water • At sea level 1 L of nitrogen dissolved in entire body, half in body fluids & half in fat ( though fat constitutes 15% of total body) • At 33 feet deep – 2 L of nitrogen get dissolved in body • At 100 feet deep 4 L of nitrogen • Nitrogen can not be metabolized in body • Diver ascends slowly to sea level • In case of rapid ascent → decompression sickness
Decompression Sickness • Decompression sickness (DCS, aka “the bends”) is the result of inadequate decompression following exposure to increased pressure
Decompression Sickness • If the diver ascends to quickly, the nitrogen absorbed by the diver’s body during a dive can come out of solution and form bubbles in the body’s fluids and tissues
Decompression Sickness • It has been common to describe decompression sickness as one of three Types, or to categorize it by the area of involvement and the severity of symptoms
Decompression Sickness • Type I includes skin itching or marbling; brief, mild pain called “niggles, ” which resolve typically within ten minutes; joint pain; lymphatic swelling, and sometimes included extreme fatigue
Decompression Sickness • Type II DCS is considered to be respiratory symptoms, hypovolemic shock, cardiopulmonary problems, and central or peripheral nervous system involvement
Decompression Sickness • Type III includes arterial gas embolism and is also called decompression illness (DCI)
FACTORS INFLUENCING DCS • Exertion • Physical fitness • Temperature – cold water, hot shower • Sex – females • Age • Obesity • Dehydration • Increased carbon dioxide pressures • • • Alcohol intake Physical injury Adaptation Dive profile Rapid and multiple ascents • Repetitive and multi -day diving • Altitude exposure
Decompression Sickness • Also called bends, compressed air sickness, caisson disease, divers paralysis, dysbarism • During rapid ascent, sufficient amount of nitrogen bubbles develop in body fluids either extra or intra cellularly • Depending upon the no & size of nitrogen bubble, any area of the body can get damage • Bubble formation in brain vessels → paralysis; Around nerves → paraesthesia itching, severe pain; Around joints → severe pain in joints (called bends); In pulmonary vessels → Dyspnoea & chokes, coronary arteries → cardiac damage
Decompression Sickness • Categorizing DCS by area involved and severity of symptom includes: • Limb Bends • Central Nervous System (CNS) DCS • Cerebral Decompression Sickness • Pulmonary DCS • Skin Bends • Inner-Ear Decompression Sickness
Decompression Sickness • Limb Bends – Dull, throbbing, deep pain in the joint or tissue; usually in the elbow, shoulder, hip, or knee • Pain onset is usually gradual and slowly intensifies • In severe cases limb strength can be affected • In divers, upper limbs are affected about three times as often as lower limbs
Decompression Sickness • Central Nervous System (CNS) DCS – May cause muscular weakness, numbness, “pins and needles, ” paralysis, loss of sensation, loss of sphincter control, and, in extreme cases, death
Decompression Sickness • Cerebral Decompression Sickness – May produce almost any symptom: headache, visual disturbance, dizziness, tunnel vision, tinnitus, partial deafness, confusion, disorientation, emotional or psychotic symptoms, paralysis, and unconsciousness
Decompression Sickness • Pulmonary DCS – aka the Chokes accounts for about 2% of DCS cases • Symptoms include: pain under the breastbone on inhalation, coughing that can become paroxysmal, and severe respiratory distress that can result in death
Decompression Sickness • Skin Bends – Come in two forms: harmless simple itchy skin after hyperbaric chamber exposure, or rashy marbling on the torso that may warn of serious DCS
Decompression Sickness • Inner-Ear Decompression Sickness – aka Vestibular DCS or Ear Bends • Signs and symptoms include vertigo, tinnitus, nausea, or vomiting
O 2 Toxicity at High Pressure • If PO 2 ↑ more than 100 mm. Hg → Dissolution of O 2 in blood ↑ also • If someone exposed to 4 atmosphere pressure (3040 mm. Hg) → seizures followed by coma within 30 -60 minutes • Seizures may appear without warning but prove lethal • other symptoms – nausea, muscle twitching, dizziness, disturbance of vision, irritability disorientation • ↑ ROS production, being lipid soluble damage the cell membrane esp; nervous tissue (as with high lipid content)
TREATMENT OF DECOMPRESSION SICKNESS INVOLVES IMMEDIATE RECOMPRESSION, FOLLOWED BY GRADUAL DECOMPRESSION
LOCALIZED PAIN IN OR AROUND A JOINT MAY SOMETIMES BE RELIEVED BY APPLICATION OF LOCAL PRESSURE, e. g FROM AN INFLATED SPHYGMOMANOMETER CUFF
PREVENTION • GRADED ASCENT • USE OF SCUBA • USE OF HELIUM
TREATMENT • HYPERBARIC OXYGEN THERAPY [RECOMPRESSION THERAPY] • SUPPORTIVE THERAPY
Effects of Heat and Cold • Heat injuries (hyperthermia) – cramps – exhaustion – stroke • Cold injuries (hypothermia) – Decreased body functions – Decreased mental functions – Shivering, numbness – Related protection requirements
Temperature Injuries Progressive Symptoms and Effects Heat Aid Cool Victim Oral Fluids No Caffeine/Alcohol Aid Uncontrolled Shivering Loss of Coord/Dexterity Numbness 1 st pto ms - Hypothermia Sym Profuse Sweating Weakness Malaise Dry, Flushed Skin 1 st Sym pto ms - Cramps - Exhaustion - Stroke Cold Warm Victim No Caffeine No Alcohol
Barotrauma Direct Pressure Related Problems Indirect Pressure Related Problems - Descent (Compression) Squeezes - Decompression Sickness (The Bends) (DCS) Ear, Sinus, Lung, Stomach, Intestinal, Tooth, Equipment - Nitrogen Narcosis Descend and Ascend Slowly to Minimize Potential Problems - Oxygen Toxicity - Ascent (Expansion) Lung Ruptures Subcutaneous and Mediastinal Emphysema Pneumothorax Air Embolism NEVER HOLD YOUR BREATH ON SCUBA! Precautionary Decompression Stops (Safety Stops) Help Reduce Bubble Formation and Incidence of DCS
• One or more tanks of compressed air or some other breathing mixture, • A first-stage "reducing" valve for reducing the very high pressure from the tanks to a low pressure level • A combination inhalation "demand" valve and exhalation valve that allows air to be pulled into the lungs with slight negative pressure of breathing and then to be exhaled into the sea at a pressure level slightly positive to the surrounding water pressure, • A mask and tube system with small "dead space. "
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