Deep Sea Diving

Deep Sea Diving & Hyperbaric Condition Atmosph = 760 mmHg 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 DIVING HIGH 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

(Dalton’s Law) 21% O2 78% N2 Partial Pressure 760 mm Hg 1% Other 95 --- 190 --- 380 --- 523 --- 760 --- 760 mm Hg

Nitrogen Narcosis at High Nitrogen Pressure About 4/5th 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

“Rapture of the Deep” - “Martini’s Law” Nitrogen narcosis Nitrogen Narcosis “Rapture of the Deep” - “Martini’s Law” SURFACE Thinking and Judgment POTENTIALLY Affected 75-100m 250-325 ft Symptoms and Effects on Individual Diver Vary With Depth and Exposure. Communication, Motor and Mental Tasks IMPAIRED 150-175m 500-575 ft NOT IN CONTROL 200m+

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

O2 Toxicity at High Pressure If PO2 ↑ more than 100 mmHg → Dissolution of O2 in blood ↑ also If someone exposed to 4 atmosphere pressure (3040 mmHg) → 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 Heat Cold Progressive Symptoms and Effects - Cramps - Exhaustion - Stroke Profuse Sweating Weakness Malaise Dry, Flushed Skin Cool Victim Oral Fluids No Caffeine/Alcohol - Hypothermia Uncontrolled Shivering Loss of Coord/Dexterity Numbness Warm Victim No Caffeine No Alcohol Symptoms Symptoms 1st Aid 1st Aid

Barotrauma Direct Pressure Related Problems Indirect Pressure - Descent (Compression) Squeezes Ear, Sinus, Lung, Stomach, Intestinal, Tooth, Equipment - Ascent (Expansion) Lung Ruptures - Subcutaneous and Mediastinal Emphysema Pneumothorax Air Embolism Descend and Ascend Slowly to Minimize Potential Problems - Decompression Sickness (The Bends) (DCS) - Nitrogen Narcosis - Oxygen Toxicity Precautionary Decompression Stops (Safety Stops) Help Reduce Bubble Formation and Incidence of DCS NEVER HOLD YOUR BREATH ON SCUBA!

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."