Amy Gutman MD ~ EMS Medical Director /

Diving Emergency Categories Environmental: Hypothermia, sunburn, physical trauma Aquatic Activities: Submersion injuries, motion sickness, envenomations Scuba Diving Injuries: Pressure changes Breathing gases at elevated partial pressures Barotrauma Arterial Gas Embolism Decompression Sickness Today’s lecture focuses on scuba-related injuries & barotrauma

Standard Management Flowchart for Diving- Related Injuries

Diving Emergencies: Boyle’s Law The volume of a gas is inversely proportional to it’s pressure if the temperature is constant Translation: The more pressure exerted on a gas, the less volume of gas there is in a closed container

Dalton’s Law Total pressure of a mixture of gases is equal to the sum of partial pressures of the individual gases Translation: Partial Pressure A = 1 Partial Pressure B = 2 Partial Pressure C = 3 A + B + C = 6 (Total Pressure) A=1B=2C=3 6

Diving Emergencies: Henry’s Law The amount of gas dissolved in a given volume of liquid is proportional to the pressure of the gas above it Pressure =

Diving Emergencies: Pathophysiology Henry’s Law: Increased dissolution of gases during descent Boyle’s Law: Gases have smaller volume in water than on surface In controlled ascents, gases escape through respiration In uncontrolled ascents, gases rapidly come out of solution (blood) forming nitrogen bubbles in tissues & organs Common: brain, skin, inner ear, muscles, joints

Diving Emergencies: Classification Surface Injuries Strangulation Descent Injuries Barotrauma Floor Injuries Nitrogen narcosis Ascent Injuries Decompression illness Pulmonary overpressure & subsequent arterial gas embolism, pneumomediastinum, or pneumothorax

Blackouts Deep Water BlackoutShallow Water Blackout Hypoxia upon ascent from depth O 2 partial pressure in lungs under pressure at bottom of a deep free-dive adequate to support consciousness at that depth O 2 levels drop below blackout threshold as the water pressure decreases upon ascent forcing gases out of bloodstream (Henry’s law) Divers often hyperventilate prior to swimming or diving Urge to exhale triggered by rising blood CO 2 levels Hyperventilation depletes CO 2 leaving diver susceptible to sudden loss of consciousness from hypoxia There is no bodily sensation that warns a diver of an impending blackout & divers victims lose consciousness & drown without alerting anyone they are in distress Typically found on ocean floor

Diving Emergencies: Assessment Ascent rate Diver experience Depth gauge function PMH including prior diving illness Prescribed / illicit meds (i.e. ETOH)

Diving Emergencies: Assessment Time of onset Breathing apparatus used Hypothermia-protective garment type worn Aircraft travel following dive Dive “Table” Parameter # dives, depth, & duration

US Navy / PADI Dive Tables DepthTime

Decompression Illness Dives >33 ft, or shallow depth if (+) PMH Nitrogen gas coming out of solution Symptoms between 5 mins-8 hrs post surfacing Clinical Manifestations: MS: joint pain, parasthesias lymphedema Neuro: seizure, HA, AMS, paralysis, fatigue GI: abdominal pain, N/V Skin: pruritis Vasomotor: hypotension, tachycardia Management: Slow, controlled hyperbaric chamber recompression

Decompression Illness Treatment ABCs & resuscitation as needed Supportive care Hyperbaric chamber recompression If air evacuated, maintain cabin pressure at sea level or fly at low altitude Send diving equipment for analysis Full cardiac & neurological work- up necessary to evaluate for underlying cause(s)

Barotrauma Mask Squeeze TM rupture Middle ear squeeze Barosinusitis / Barodentalgia Vertigo Suit squeeze GI barotrauma Mediastinal emphysema Pneumothorax / Hemothorax

Arterial Gas Embolism Severe form of barotrauma Onset of symptoms immediately upon ascent CVA, MI, cardiac arrest, LOC, seizure, HA Suspect in patient with neurological deficits immediately after ascent Pressure induced gas transfer across alveolar-capillary membrane causes bubbles to enter arterial circulation Treatment is hyperbaric chamber & resuscitation

Arterial Gas Embolism Can Occur in Brain, Lungs, Heart, Joints, Skin

Arterial Gas Embolism Treatment ABCs, IV, Monitor Airway management Resuscitation as needed Supine position or reverse Tradeleburg Frequent vital signs Corticosteroids? Rapid transport to a recompression chamber

Pulmonary Overpressure Failure to exhale during ascent Can occur with dives in <6 ft of water Lung rupture leaks air into pleural space compressing lung & aorta SSX: Bloody sputum Chest pain Reduced chest movement Respiratory distress Treat as a pneumothorax

Pneumomediastinum Failure to exhale during ascent Lung rupture forces air into neck, mediastinum, around heart & other organs Symptoms Bloody sputum / dyspnea Chest pain Arrythmia Hypotension with narrow pulse pressure Neck swelling, difficulty swallowing, hoarse voice Chest wall feels like “rice krispies”

Nitrogen Narcosis Occurs during dive Signs and Symptoms AMS Impaired judgment may lead to further injury Treatment Return to shallow depth Hyperbarics Use O 2 /helium mix during dive (heliox)

Diving Emergencies Patients generally triaged to local hospital for initial stabilization, then transferred to hyperbaric- capable facility Diver’s Alert Network Consultation & referrals 24/7 (919) Dan the Diving Dog

References NFPA 1670 DAN Network Wikipedia, Google Buzzacott P. Epidemiology of injury in scuba diving. Med Sport Sci Salahuddin M. SCUBA medicine: a first- responder's guide to diving injuries. Curr Sports Med Rep. 2011

Summary / Diving physics review Assessment & management of diving injuries Treatment involves ABCs, stabilization & symptomatic management, & often resuscitation followed by a dive in a hyperbaric chamber