Diving Medicine LCdr Peter Hatfield

Objectives Barotrauma Decompression Illness Gas Problems Putting it together

1. pre-existing medical condition eg myocardial infarction 2. trauma/drowning/hypothermia 3. Barotrauma 4. Decompression Illness 5. Gas Problems

Barotrauma Boyles Law Volume inversely proportional to pressure

Gas attempts to contract or expand IAW Boyle’s Law In closed spaces, gas cannot enter or escape Therefore, a pressure differential will develop Squeese or reverse squeese

1. Non pulmonary barotrauma suit/mask squeeze sinuses ears teeth bowel 2. Pulmonary barotrauma arterial gas embolism mediastinal emphysema pneumothorax subcutaneous emphysema

Suit/mask squeeze

Ears/Sinuses

Ears Barotrauma Teeds 0-5 Alternobaric vertigo Draeger Ear Perilymphatic fistula Facial Baroparesis

Barotrauma Treatment Middle Ear Restrict diving until resolved; Mild (0-1) 24 to 72 hours Moderate (2-3) 1 to 8 days Severe (4-5) may take up to six weeks decongestant , +/- antibiotic Perilymphatic fistula ENT referral – may need surgery Facial Baroparesis need to reverse due to ischemia -myringotomy

Dental- fractured tooth/abcess Bowel- possible surgical consult On ascent or descent

Pulmonary Barotrauma Potential alveolar rupture from 1 msw (3 fsw) water depth

Pulmonary Barotrauma 1. Arterial Gas Embolism 2. Pneumothorax 3. Mediastinal Emphysema 4. Subcutaneous Emphysema

Local air trapping in lungs Breath-hold on ascent Panic, buddy breathing, laryngospasm Local air trapping in lungs Obstructive lung disease, scarring/fibrosis Frequent Change in Pressure

Symptoms Can co-exist Rapid onset (less than 5 min) Likely on ascent Conscious/LOC Any neurological symptom/sign (internal carotid most likely) Hemoptysis Shortness of breath High pitched cry Pleuritic type Chest pain Subcutaneous emphysema Can co-exist with pneumothorax or mediastinal/subcutaneous emphysema

Treatment ABC s Lie down, on side if unconscious Head down only for short time if at all Catheterization if unconscious 100% oxygen Transport to nearest RCC Maintain 1 ATA ambient pressure if possible

Treatment Table 6 4 Hours 46 Minutes 30 09 m (30 ft) 5 20 5 20 5 20 5 30 09 m (30 ft) 5 20 5 20 5 20 5 20 5 20 5 20 30 ASCENT RATE: 0.3 m/min (1 ft/min) 18 m (60 ft) 20 5 20 5 20 5 DESCENT RATE: 18 m/min (60 ft/min) O2 periods 3 at 18 msw (60 fsw) 6 at 09 msw (30 fsw)

Time to Tx of A.G.E. and Response

Decompression Illness Compressed air 79% nitrogen 20% oxygen

Venous bubbles unlike AGE Left/right shunt could become arterial eg patent foramen ovale 1929 Clark infused 2,000 ml air at 50ml/hour into a dog with no signs of DCI Asymptomatic Military divers can be shown to have bubbles (on doppler) after experimental dives

Deeper/longer dives Inadequate decompression Age Fatigue before diving Cold during decompression Heavy exercise before during or after diving Dehydration (alcohol consumption) Infection, medication Flying after diving Rapid decompression at altitude

Bubbles cause Blood / bubble interface activates blood components Body treats the bubble as a foreign object and coats it in protein RBC agglutination, platelet consumption, vascular permeability, leukocyte activation, etc. Endothelial injury. Bubbles activate complement system in some individuals.

Decompression sickness/stress Continuum No dive No stress Death Severe DCS Type II Mild DCS Type I Decompression stress with symptoms stress without

Mild Symptoms Severe Symptoms Fatigue Fleeting joint discomfort (niggles) Skin itch and erythema Joint pain Lymphatic Skin (cutis marmorata) Severe Symptoms CNS/ Spinal Labyrinthine (staggers) Pulmonary (chokes)

Time to symptoms During decompression Rare 0-30 min 50% 30-60 min 75% 1-6 hours 90% 6-12 hours 95% 12-24 hours 99%

Treatment 100 % oxygen delivers oxygen to tissues nitrogen gradient (elimination) IV Ringers/normal saline RCC even if symptoms have resolved

Gas Problems SYMPTOMS AT DEPTH Nitrogen Oxygen Carbon Dioxide Impurities O2 CO Partial pressure at 1ATA =.21 0.01 % At 30m 4ATA =.84 0.04 At 60m 7ATA =1.47 0.07

Oxygen Toxicity CON – Convulsion V – Visual aberrations Pulmonary CNS occurs at partial pressure 1.6 ATA O2 70m on air 6m on 100% O2 CON – Convulsion V – Visual aberrations E – Ears, ringing, bells, etc. N – Nausea T – Twitching of facial muscles I – Irritability, behavior changes D – Dizziness

Nitrogen narcosis Carbon dioxide Martini’s law - 1 martini per every 10 m after 20m depth Carbon dioxide 1-10 % symptoms Headache, nausea, fatigue, sweating, tachycardia SOB, confusion

Putting it Together History - most important dive buddy Where did the symptoms start and When descent bottom surface 1) immediately 2) delayed Type of dive Prexisiting conditions

Physical exam- ABC s neuro exam Signs- resolving, static, progressing AGE or DCS treatment is the same “4 min neuro”

examples Case 1 Vertigo 21 year old diver with cold symptoms, pain in ear on descent. Forced valsalva- sudden ( in water) onset of vertigo, tinnitus, hearing loss Barotrauma to ear alternobaric vertigo perilymphatic fistula Did he get better on the surface Compare Diver on air 30m for 25 minutes -no decompression stops. Develops vertigo tinnitus hearing loss 30 mins after surface Diver on air 10m for 120 minutes

Case 2 Diver on air 15m after 10 mins at depth feels dizzy, headache, nausea Surfaces feels fine after 5 mins O2 CO2,CO, anxiety, non diving medical condition

Case 3 24 yr old diver feels unwell at 30m after 20 mins. On surface anxious tingling in the face and arms feels fatigued, rapid breathing Physical normal Unsure – trial of pressure?

Trial of Pressure/Treatment Table 5 2 Hours 16 Minutes 30 09 m (30 ft) 5 20 30 ASCENT RATE: 0.3 m/min (1 ft/min) 18 m (60 ft) 20 5 20 5 DESCENT RATE: 18 m/min (60 ft/min) O2 periods 2 at 18 msw (60 fsw) 1 at 09 msw (30 fsw)

Case 4 Diver on vacation several consecutive days diving. Flying home develops pain in shoulder. Can calculate “repat” group or wait 24 hours. Do not dive on a travel day

Case 5 Diver 40m for 30 mins returns to surface within 5 mins develops weakness in left arm, CN VI palsy and ataxia ?AGE or DCI