Dive Physiology And Medical Aspects

Underwater Physiology Respiration Effects of heat and cold Barotrauma Pressure related problems –Direct –Indirect

Respiration The breathing cycle Oxygen consumption Carbon dioxide Breath holding Hypoxiahypercapnia/hypocapnia Carbon monoxide poisoning

Respiration Air Must Pass Through “Dead” Spaces Respiration The Process Movement of air into and out of the lungs Transport of oxygen to the cells and removal of carbon dioxide Approx. 5% Oxygen Consumed Carbon Dioxide Increases 5% Shallow Water Blackout Caused by Excessive Hyperventilation Skip Breathing Causes Hypercapnia Air with Less Than 10% O2 at 1atma Will Not Support Consciousness Mouth, Nose, Throat Diaphragm Lungs Trachea Bronchi Bronchioles AlveoliHeart Lungs Capillaries Vena Cava AortaPulmonary Artery Pulmonary Vein CO 2 O2O2 O2O2 Hemoglobin Molecules in Red Blood Cells Carry Oxygen

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 Cold - Cramps - Exhaustion - Stroke Profuse Sweating Weakness Malaise Dry, Flushed Skin Cool Victim Oral Fluids No Caffeine/Alcohol Symptoms - Hypothermia Uncontrolled Shivering Loss of Coord/Dexterity Numbness Warm Victim No Caffeine No Alcohol Symptoms 1st Aid

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

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

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

Physiology Summary Respiration is Mechanica l - Oxygen-Carbon Dioxide Exchange - Slow Deep Breathing Barotrauma - Pressure Injury - Direct Subcutaneous Emphysema Mediastinal Emphysema Pneumothorax Air Embolism - Indirect DCS (the Bends) Nitrogen Narcosis Oxygen Toxicity Proper Exposure Protection is Required to Avoid Hypothermia