KIN 3304 1nd Edition Lecture 28 Outline of Last Lecture I Muscles of Inspiration II Muscles of Expiration III Muscles of Inspiration and Expiration IV Spirometry V Lung Volume and Capacities Chart VI Numbers VII Fick s Equation Outline of Current Lecture I Pressure II DCI III DCS IV AGE V Lung Overexpansion Injuries VI Patent Foramen Ovale VII Nitrogen Narcosis VIII O2 Toxicity IX CNS O2 Toxicity X Hypocapnia These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute XI Hypercapnia XII Carbon Monoxide Poisoning XIII High Pressure Nervous Syndrome Current Lecture I Pressure a Pressure the continuous physical force exerted on or against an object by something in contact with it b Pressure force area c Pressure is measured in atmospheres as pound per square inch d Water is about 800 times more dense than air e The pressure we feel exerted on our body in 10 miles of air is equaled by a mere 33 feet of sea water i So for every 33 feet of sea water we gain 1 atm 1 Edge of space to sea level 1 atm 2 33 feet of sea water 2 atm f II Pressure is one of the main factors to consider when discussing diving physiology DCI a Decompression Illness i A term used to describe illness that result from a reduction in the ambient pressure surrounding a body b 3 types i DCS decompression sickness ii AGE arterial gas embolism iii Lung overexpansion injuries III DCS a Decompression sickness b AKA caisson disease or the bends c 2 8 cases per 10 000 dives i Male 2 6 times greater risk than females d First people to get this were construction workers IV AGE a An embolism is anything in the blood stream that can block blood flow i AGE then is a bubble on arterial side b Can block blood to parts of the body V Lung Overexpansion Injuries a Pneumothorax i Rupture of a lung in pleural cavity collapsing the lung either partially or completely b Mediastinal Emphysema i Air is trapped in center of chest pressing on heart and major blood vessels c Subcutaneous Emphysema i Occurs frequently in conjunction with mediastinal emphysema d Most people die just 30 feet under VI Patent Foramen Ovale a Relatively little effect on non divers b Bubble can be found in blood after dives i Normally trapped by the lungs and filtered out ii Bubbles in people with PFO bypass the lungs and can lead to complications such as DCS VII Nitrogen Narcosis a Pressure incurred while diving cause gases to dissolve into the blood allowing a higher percentage to reach nervous system b This higher amount causes narcotic effect such as euphoria or anesthesia i Like laughing gas N2O that dentists use c You can pass out under water VIII O2 Toxicity a The air we are breathing is 78 N 20 93 O2 0 03 CO2 and 1 trace gases b Pure O2 can be lethal beyond 30 ft c Deeper depths and higher concentrations of O2 raise risk of O2 Toxicity d 2 Types of O2 Toxicity i Pulmonary ii Central Nervous System IX CNS O2 Toxicity a Far more serious than pulmonary toxicity i CNS toxicity doesn t have a useful PO2 and time relationship b Symptoms relate to CNS including visual disturbances ear disturbances nausea twitching irritability and dizziness c Most serious problem is hyperoxic seizure X Hypocapnia a Hypocania lack of CO2 b From either voluntary hyperventilation or unintentional due to stress or freight c Can lead to shallow water blackout XI Hypercapnia a Usually the result of over exertion but can be from dead air spaces mask snorkel b Related to skip breathing i Causes headaches confusion and a feeling of air starvation ii Loss of consciousness is your body s way of resetting proper breathing but is problematic for divers XII Carbon Monoxide Poisoning a Contaminated air can contain carbon monoxide b Hemoglobin binds with CO 20x more readily than O2 i Bind forms carboxyhemoglobin ii Can take 8 to 12 hours to eliminate once in the respiratory system c Increased pressure allows O2 to continue bonding at depth but as the diver ascends and pressure is reduced O2 bonding fails and diver passes out XIII High Pressure Nervous Syndrome a Related to deep diving i Can happen as shallow as 300 ft but more commonly associated with depths beyond 400 ft b Symptoms i Hand tremors cramps nausea vertigo loss of coordination c No clear cause i Results from helium interfering 1 Can be offset by narcotic effect of using nitrogen or hydrogen
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