Title: High Altitude Problems And Dysbarism
1High Altitude Problems And Dysbarism
2Preamble
- General Characteristics
- Incidence depends on
- Rate of ascent
- Final altitude
- Sleeping altitude
- Duration at altitude
- Individual susceptibility
3Acute Mountain Sickness
- Incidence
- 67 with rapid ascent
- 20 for skiers visiting resorts
- 15-20 with ascent to 8,5009000ft in one day
4Acute Mountain Sickness
- Clinical Manifestations
- Generally benign and self-limited
- Onset 4-12hrs after ascent
- Headache, fatigue, dizziness, weakness
- Anorexia/ nausea/ vomiting
- Lightheadedness
- Difficulty sleeping due to periodic breathing
- Ataxia
5Acute Mountain Sickness
- ? ?
- Viral syndrome
- Exhaustion
- Alcohol hangover
- CO poisoning
6Acute Mountain Sickness
- Treatment
- Mild cases
- Self-limited
- Symptomatic treatment
- Halt ascent till symptoms resolve
- Acetazolamide
- For prevention and treatment
- 250mg BD starting 24hrs prior to ascent
7Acute Mountain Sickness
- Aspirin/ acetaminophen
- Prochlorperazine
- Dexamethazone
- Supplemental oxygen
- Descent for severe or persistent symptoms
- Simulated descent with GMT
8Acute Mountain Sickness
                                              Â
       Â
9Acute Mountain Sickness
- Prevention
- Graded Ascent
- Avoid increase in sleeping greater than 2,000ft
when over 8,000
10High Altitude Pulmonary Edema
- Incidence
- lt 1-2
- Affects 0.01 of skiers in Colorado/yr
- Affects 1in 50climbers of Mt. McKinley
- Varies with rate of ascent
11High Altitude Pulmonary Edema
- Pathophysiology
- Non-cardiogenic PE
- Precise pathophysiology is unknown
- Combination of alveolar leakage with
overperfusion - Impaired endothelial/epithelial barrier
- Intense pulmonary artery vasoconstriction
12(No Transcript)
13High Altitude Pulmonary Edema
- Clinical Presentation
- Occurs 2-4 days after ascent
- Fatigue / weakness
- Cough / dyspnea at rest / tachypnea
- Rales
- Cyanosis
- Severe respiratory distress and death
14High Altitude Pulmonary Edema
- ? ?
- Pneumonia
- High altitude bronchitis and pharyngitis
- PE
15High Altitude Pulmonary Edema
- CXR findings
- Patchy infiltrates with areas of clearing between
the patches - Unilateral or bilateral
- Cardiomegaly, bat-wing distribution of
infiltrates and kerley-B lines are absent
16HAPE
17High Altitude Pulmonary Edema
- Treatment
- ABCs
- Supplemental O2
- Descent
- Bed rest
- Nifedipine
- Lasix, morphine, acetazolamide
18High-Altitude Cerebral Edema
- Incidence
- lt 1
- Life-threatening
- Occurs in the presence of HAPE
- Rarely seen as an isolated entity
19High-Altitude Cerebral Edema
- Clinical Manifestations
- Develops within 3-4 days
- May occur 12hrs after the onset of AMS
- Nausea / vomiting
- Severe headache
- Ataxia / focal neurological deficit / seizures
- Altered mental status
- Coma
20High-Altitude Cerebral Edema
21High-Altitude Cerebral Edema
- Treatment
- ABCs
- Immediate evacuation to lower altitude
- O2
- Dexamethazone
- Bed rest
22High-Altitude Retina Hemmorhage
- Common at altitude gt 17,500
- Incidence unknown
- Related to strenuous exercise at high altitude
- Noted commonly in presence of severe HACE or HAPE
- Usually self limited and resolve within 2-3wks
23HARH
24Dysbarisms
- Dysbarisms are illnesses that result directly or
indirectly from exposure to increased ambient
pressure.
25Decompression Sickness
- Gas Laws
- Henrys Law
- Daltons Law
- Boyles Law
26Decompression Sickness
- Mechanism
- ? ambient pressure? pN inspired
- N accumulates in tissues in higher concentration
the longer the pressure remains high - DCS results when pressure keeping the N in
solution ? too rapidly on ascent ? bubble
formation
27Decompression Sickness
- Risk Factors for DCS
- Greater depth, longer bottom timeand quicker rate
of ascent - ? age, ? weight (body fat),
- Hypothermia
- Dehydration, exercise, multiple dives in a day
- Lower cabin pressure
28Decompression Sickness
- Clinical Manifestations
- Time after surfacing to presentation of DCS
- 50- symptoms within 1hr
- 95- symptoms within 12hrs
- 60 of neurologic DCS within 10minutes
29Decompression Sickness
- Clinical Manifestations
- Cutaneous
- Scarlatiniform, erisipeloid or mottled rash
- Peau dorange appearance
- Musculoskeletal (no external physical signs)
- Pain
- Classic bends
- Dull deep aching ( joints- elbow and shoulder
- Not exacerbated by movement or reproduced with
palpation
30Decompression Sickness
- Pulmonary
- Dyspnea
- chokes
- Substernal pressure
- Cough
- Dyspnea
- GI
- Nausea / vomiting
- Abdominal pain
31Decompression Sickness
- CNS
- Weakness / fatigue / lethargy
- Numbness / paraesthesia
- Agitation
- Headache
- Dizziness, vertigo, visual disturbance
- Convulsion
- Bowel/bladder incontinence
- Staggers
32(No Transcript)
33(No Transcript)
34Decompression Sickness
- Treatment
- ABCs
- ETT
- Early recompression in hyperbaric chamber
- For all DCS
- Tranportation to nearest hyperbaric facility
- Chest tube
35Decompression Sickness
- IV Rehydration with 0.9NS
- Water Recompression
- Divers Alert Network (919)684-8111
36Barotrauma
- General
- Injury to the body as a result of expansion and
contraction of gas in an enclosed space - Boyles Law
- PVK
- Gas filled cavities
- Sinus
- Middle ear
- Lung
37Barotrauma
- Clinical Manifestations
- Middle ear
- Most common type of barotrauma
- Barotrauma of descent
- 10 Vs 30 incidences
- Eustachian tube patency
38Barotrauma
- Begins as a clogged sensation
- ? pain with pressure differential across TM ?
- rupture of TM.
- TM appearance TM congestion ? TM edema ?
- Gross hemmorhage ? TM rupture
39Barotrauma
- Treatment
- Decongestants
- Antihistamine for allergic component
- Antibiotic for TM rupture
- Prevention with decongestant prior to dive
40Barotrauma
- Inner Ear
- Barotrauma of descent
- ?middle ear pressure ? ?ICP ? rupture of round
or labyrinth windows - Sudden severe vertigo, disorientation, tinnitus,
nystagmus, sensorineural hearing loss - Rx
- Bed rest, avoid straining, surgical repair
41Barotrauma
- Paranasal sinuses
- Barotrauma of descent
- Failed pressure equalization by ostia ?
congestion, edema and hemmorhage - Sinus congestion, pain, epistaxis
- RX
- Decongestant
- Antibiotics for severe cases
42Barotrauma
- Gastrointestinal (aerogastralgia)
- Barotrauma of ascent
- Swallowed air expand with ? external pressure
- Excessive belching
- Flatulence
- Abdominal distension
43Barotrauma
- Pulmonary
- Occurs with ascent
- ? risk with COPD, asthma
- Lungs expand against closed glottis
- Can cause arterial gas embolism
44Barotrauma
- Signs/symptoms
- Dyspnea
- Cough with frothy red sputum
- Subcutaneous emphysema
- Delayed symptoms- bull neck appearance,
dysphagia, changes in voice character - Treatment
- 100 O2 for ill patients
- ?Intubation
- Needle thoracostomy for tension pneumothorax
45Barotrauma
- Others
- Barodontalgia
- External objects
- Dive suit / mask
46Arterial Gas Embolism
- General Xteristics
- Extreme manifestation of pulmonary barotrauma
- 2nd leading cause of dive-related death
- Overpressurization of lung tissue ? pleural tear
-
- ? air entering vascular circulation
47Arterial Gas Embolism
- Etiology
- Breathholding during ascent
- Pulmonary AV shunts or paradoxical embolism via a
patent foramen ovale - Iatrogenic
- Penetrating wounds
48Arterial Gas Embolism
- Clinical Manifestations
- Cerebral
- Stroke (dive-related)
- Any combination of neurologic deficit
- Apnea and full C-P arrest
- Altered/loss of consciousness 40
- Sensory loss/ motor deficit 20
- Paraplegia 10, seizures 4
- Visual changes, aphasia, paraesthesia
49Arterial Gas Embolism
- Pulmonary
- SOB
- Bloody, frothy sputum
- Subcutaneous air
- Cardiac
- MI
- ? CO
- Hammans sign
- Renal
- Renal infarction
50Arterial Gas Embolism
- Treatment
- Initial stabilization
- ABCs
- 100 oxygen by tight fitting mask
- Intubation
- IV access
- Hyperbaric Oxygen Recompression Therapy
- For all CAGE
- Tredenlenburg position
51KEY CONCEPTS The protective physiologic
response to a decrease in PaO2 at high altitude
is an increase in ventilation known as the
hypoxic ventilatory response (HVR). Patients with
a low HVR, which is mediated by the carotid
bodies, may be at higher risk for acute mountain
sickness (AMS). Acetazolamide, which is a
carbonic anhydrase inhibitor that induces a
bicarbonate diuresis, accelerates natural
acclimatization to high altitude. The symptoms
of AMS can resemble a viral syndrome, and include
headache, nausea, anorexia, fatigue, and
insomnia. High-altitude pulmonary edema is a
noncardiogenic form of pulmonary edema that is
best treated by descent and oxygen. Cerebellar
ataxia is the most important sign indicating that
AMS has progressed to high-altitude cerebral
edema.