Transcript File - CCFP-EM

Decompression Illness &
Barotrauma
Richard Dionne MD
Emergency Medicine – University of Ottawa
March 2013
Decompression Illness & Barotrauma
• Goals & Objectives
• Comprehensive understanding of Boyle’s Law, Henry’s Law and
Dalton’s Law of physics…
• Comprehensive understanding of Dysbarism
• Discuss the clinical presentation, prevention and interventions in
DCI type 1 & 2
• Discuss the principles of Barotrauma and the principles of
Hyperbarics
• Discuss a differential diagnosis based on history alone
Diving injuries
Group of illnesses resulting from pressure changes…
• Barotrauma
• POPS
• Alternobaric vertigo (ABV)
• Decompressions Illness (DCI):
– Decompression Sickness (DCS type 1 & 2)
– Arterial Gas Embolism (AGE)
– Nitrogen Narcosis
Question
Most of the diving injury related deaths are
secondary to:
a) Barodontalgia
b) Stroke from an Arterial Gas Embolus
c) Drowning
d) Bends
e) DCS type II
Question
Most of the diving injury related deaths are
secondary to:
a) Barodontalgia
b) Stroke from an Arterial Gas Embolus
c) Drowning
d) Bends
e) DCS type II
Case
A 25 y/o male taking his first SCUBA
lesson at a local pool
Once down at the bottom of the pool,
he ascends in a panic …
He starts feeling short of breath,
coughing, & he mentions that he
coughed up a little bit of blood...
Barotrauma
Going up or down?
Name that Law!
With depth ↑ pressure & ↓ gas volume…
Boyle’s Law
• Twice the pressure = ½ the volume
• Holding breath during ascent =
pulmonary barotrauma
Boyle’s Law
• Problem : Over pressurization on ascent
Boyle’s Law
• Tissue damage results when gas-filled space does not
equalize its space with external pressure…
Boyle’s Law
• PV=K … or … P1V1 = P2V2
• P=pressure / V=volume / K= constant
• As pressure increases/ decreases, volume decreases
/ increases
Ottawa Base Hospital Program
Boyle’s Law
• PV = K
• Physiology:
– Sea level
– Altitude 18 000 feet
– Diving 33 feet
– Diving 66 feet
1 Atm = volume gas
0,5 Atm = 2 X vol. gas
2 Atm = ½ X vol. gas
3 ATA = ⅓ X vol. gas
Pulmonary Barotrauma
• Closed glottis (no expiration) when surfaces…
• Pneumothorax / Pneumomediastinum
– “POPS” pulmonary over pressurization syndrome
– Occurs at low depth (10 feet)
• Arterial Gaseous Embolism ?
– No, usually deeper and longer
– Have to dissolve gas for this to occur
Descent Barotrauma (Squeeze)
• Compression of gas in enclosed space
–
–
–
–
–
Mask Squeeze
Ear & Sinuses
Lungs & airways
GI tract
Recent dental extraction, sockets / fillings
• Severe, sharp pain, edema or hemorrhage
Ear Barotrauma
• Middle ear
– Tympanic rupture / hemorrhage / vertigo
• Internal ear
– Round or oval window rupture with perilymph
fistula
– Hearing loss / tinnitus / vertigo etc.
• Alternobaric Vertigo (ABV)
– Change in pressure labyrinthe on ascent
– Vertigo / nausea / vomiting / hearing loss
Middle Ear
Internal Ear
Treatment
• Pseudoephedrine pills or nasal spray
– Prophylaxis before dive (60 mg)
– No dive if < 2 weeks from URTI
– Frenzel maneuver
• Suspect Internal Ear Barotrauma
– No Valsalva / no diving
– Decongestant & NSAIDS for pain
– Antibiotic prophylaxis if tympanic
perforation
– Consider Prednisone for Teed 3-4
– ENT consult & audiogram: urgent Teed 5
Tympanic Membrane : TEED Scale
 Teed 1
congestion around umbo
 Teed 2
congestion of entire TM
 Teed 3
Hemorrhage in middle ear
 Teed 4
Extensive middle ear hemorrhage with blood bubbles / TM rupture
 Teed 5
Entire middle ear is filled with dark deoxygenated blood
Question
Active divers can have a progressive hearing loss
in the 4000 – 8000 Hz range.
(Which is otherwise known as the “spouse’s
voice” range…)
a) True
b) False
Question
Active divers can have a progressive hearing loss
in the 4000 – 8000 Hz range.
(Which is otherwise known as the “spouse’s
voice” range…)
a) True
b)False
Cochlea
Decompression Illness (DCI)
Decompression Sickness Type I & II
Arterial Gas Embolism
Case
• 22 y/o recreational diver lost
consciousness while ascending
• Within 30 sec. started coughing pink,
frothy sputum
• The diver has left lung field diminished
air entry… Complaints of left sided
numbness …
Question
Which treatment is not indicated in primary
care of a diving injury?
a) Aspirin
b) Trendelenburg position
c) 100 % Oxygen
d) IV fluids
Question
Which treatment is not indicated in primary
care of a diving injury?
a) Aspirin
b)Trendelenburg position
c) 100 % Oxygen
d) IV fluids
Dysbarism
1. Change volume / pressure in compartments
containing gases …
2.  partial pressure of dissolved gas…
3. Gas bubble formation in tissue & blood system …
4. CNS system changes with  pressure
Arterial Gaseous Embolism
 Air bubble forced through alveolar-capillary
membrane and into circulation …
 distal embolism : limb / cerebral / coronary / etc.
 Presentation : < 10 min. in 90%
 Pulmonary symptoms in 25%-50%
 Treatment : Hyperbaric Chamber ...
Arterial Gaseous Embolism
• Expanding air on ascent forces air bubbles through alveolarcapillary membrane into circulation
• Location, Location, Location
– Distal embolism: limb / cerebral / coronary etc.
• 90 % of pt’s present in < 10 min from surfacing
• Pulmonary symptoms in 25 – 50 %
• Major cause of death & disability among divers
Nitrogen bubbles
The formation of bubbles can harm
the body by:
a)
b)
c)
d)
Blocking vessels
Causing localized swelling
Tearing and rupturing vessels
All of the above
Nitrogen bubbles
The formation of bubbles can harm
the body by:
a)
b)
c)
d)
Blocking vessels
Causing localized swelling
Tearing and rupturing vessels
All of the above
Physiology
 Dalton ’s Law...
Pt = PO2 + PN2 + Px
 Total pressure exerted by a mixture of gases is equal to the sum of the
partial pressure of each of the component gases…
 Henry ’s Law...
Cx = Px X solubility
 Amount of gas that will disolve in a solution is directly proportionnal to the
partial pressure of that gas…
 Increase partial pressure = more gas dissolved
 Decrease partial pressure = gas coming out of the solution
Henry’s Law
Solubility of a gas is directly proportional to the
pressure exerted on this gas …
Some gases have different solubility at different
pressures ...
• Problem:
– Nitrogen is dissolved in tissues on descent, but needs to be
released gradually on ascent. If too rapid, it stays trapped
and forms gas bubbles within the tissue and bloodstream.
Case
• Sunday evening you are called for a 28 y/o with paresis
& paresthesias both legs …
• Gradual onset for the last 12-18h…
• Patient has voiding difficulty…
• Mentions a light headache, dizziness with joint pains…
• He asks you could this be related to his dive 24hrs
before? ?
History
•
•
•
•
•
•
•
•
Depth and length of dive ?
Decompression stop times ?
Dive computer used ?
How many dives in last 72 hrs ?
Delay from last dive to air travel ?
Symptoms on descent or ascent ?
Symptoms at surfacing or delayed ?
Please remember to bring the equipment…
Decompression Sickness
«Pathophysiology»
 Nitrogen gas bubbles formation in tissue and
vascular system … during ascent ...
 Increase in Nitrogen concentration in tissues as
dive prolongs …
 Bubbles are formed as you surface
 Mecanical obstruction from bubbles
 Promotes platelet aggregation & thrombosis
 Nitrogen is  liposoluble …  CNS fragility
Decompression Sickness (DCS)
• 95% symptomatic < 24 h ...
• DCS type I
– « Bends »
– Polyarticular pains / skin tightness
• DCS type II
– neurological & cardiovascular symptoms
– headache / diplopia / confusion / ataxia /
CVA / seizure / paresthesia / para-paresis
(T12-L1…))
Decompression Sickness
Recompression & 100% oxygen helps
DCS by:
a)
b)
c)
d)
Mechanically compressing bubbles
Washing nitrogen out of the tissues
Reducing swelling
All of the above
Decompression Sickness
Recompression & 100% oxygen helps
DCS by:
a)
b)
c)
d)
Mechanically compressing bubbles
Washing nitrogen out of the tissues
Reducing swelling
All of the above
Decompression Sickness
• Even in lower altitude
– Commercial planes pressurized at 5000 ft
• Plane after diving…
– 12 hr after dive (< 2 hr) in last 48 hr
– If multiple dives / unlimited … suggest 24 –
48 hr
• Plane or diving after DCS
– Type 1: after 7 days
– Type 2: after 4 weeks
Question
Is it safe to fly a Decompression Illness patient, if
the pilot maintains an altitude of less than
500 ft (152 m) above the departure point.
a) True
b) False
Question
Is it safe to fly a Decompression Illness patient, if
the pilot maintains an altitude of less than
500 ft (152 m) above the departure point.
a) True
b) False
Gas Toxicity
Nitrogen Narcosis
Diving breathing gas mixtures
• Compressed air (common for dives < 130 feet)
– Nitrogen (78%), Oxygen (21%), gases (1%)
• Nitrox – mixture of oxygen (more than 21%) & air
– Accelerates decompression
– Decrease risk of DCS
• Trimix – mixture of oxygen, nitrogen & helium
– Technical / commercial diving at depth
– Reduces nitrogen narcosis
• Heliox, Heliair, Hydreliox, Neox …
Nitrogen
• Theoretical models help predict rate of nitrogen absorption
• DCS can happen even in a perfectly planned dive
• Absorption rate depends on:
– Nitrogen partial pressure
– Tissue perfusion
– Tissue fat content
Nitrogen Narcosis
• Rapture of the deep
• Deep or prolonged dive
• Symptoms
– Euphoria / Confusion / Disorientation
– Change in judgement
– Impaired motor function &
Paresthesia
Question
Nitrogen is 5 x more soluble in fat tissue.
That is why women are at increased risk for
Decompression Sickness involving the Central
Nervous System.
a) True
b) False
Question
Nitrogen is 5 x more soluble in fat tissue. That is
why women are at increased risk for
Decompression Sickness involving the Central
Nervous System.
a) True
b) False
Nitrogen Narcosis
Treatment
•
•
•
•
•
•
100 % Oxygen
Position: No trendelenburg
ASA PO
IV fluids
Prevent hypothermia
Hyperbaric
Oxygen Toxicity
• Breathing Oxygen enriched gases (ex. Nitrox)
• Once the alveolar PO2 rises above a critical level
• ↑ PO2 increase… ↑ toxicity
• Hemoglobin-oxygen buffering mechanism fails
• Brain is most sensitive to high oxygen pressure
• Oxygen free radicals toxins
• Seizures (at depth), nausea, dizziness, visual disturbances,
disorientation … ARDS…
Differential & Treatment
Possible just with the history !
History
• Depth and length of dive ?
• Decompression stop times ?
• Dive computer used ?
• How many dives in last 72 hrs ?
• Delay from last dive to air travel ?
• Symptoms on descent or ascent ?
• Symptoms at surfacing or delayed ?
• Please remember to bring the equipment…
Differential
Rosen’s 5th Ed. P. 2027 Figure 137-2
Onset of symptoms?
Descent
Depth
Middle Ear Barotrauma
Internal Ear Barotrauma
Facial Barotrauma
Sinus Barotrauma
Nitrogen Narcosis
Hypothermia
Contamination
Oxygen toxicity
Ascent
Rapid Ascent
ABV
POPS
AGE
Pneumothorax
Pneumomediastinum
Pulmonary hemorrhage
GI & Dental barotrauma
Long / Deep Dive Profile
DCS 1 & II
Hyperbaric Chamber
• Arterial gas embolism & Decompression Sickness
• AGE , DCS
• U.S. Navy Protocols… Table 5 & 6
• General protocol is:
– Wear 100% cotton (highly flammable
environ.)
– Dive to 2.5 ATM (50 feet)
– 3 – 30 min sessions in 100 % oxygen
– 10 min air / breaks to prevent oxygen toxicity
– 5 treatments usual, but more according to dx
Hyperbaric Chamber …
Diving Injuries
Barotrauma
Mask squeeze & Barosinusitis
Middle & Internal Ear Barotrauma
ABV - Alternobaric vertigo
Pulmonary Barotrauma
Intestinal Barotrauma
Dysbarism
Decompression Sickness : type I & II
Arterial Gaseous Embolism
Nitrogen Narcosis
Take home ...
 History is very important …
 Increase in sport scuba divers ...
 Trendelenburg may increase risk of elevated ICP & coronary
embolus = not indicated…
 Most diving injuries are self-limited …
 A.G.E. / D.C.S. I & II = « Hyperbaric »
 Aware of closest «Hyperbaric Facility»
Take home ...
 History is very important …
 Increase in sport scuba divers ...
 Trendelenburg may increase risk of elevated ICP & coronary
embolus = not indicated…
 Most diving injuries are self-limited …
 A.G.E. / D.C.S. I & II = « Hyperbaric »
 Aware of closest «Hyperbaric Facility»
Questions ?
Ottawa Base Hospital Program
Want more?
• DAN:
– www.diversalertnetwork.org
– Emergency Hotline (919) 684-8111
– Non-emergency (919) 684-2948
• Undersea & Hyperbaric Medicine
• Wilderness & Environmental Medicine
Submersion Injuries
Richard Dionne MD
Emergency Medicine – University of Ottawa
March 2013
Case
A 4 yr old boy is found face flat semi-floating in the
pool, after his mother heard screaming from his
older sister…
 What do we need to know ?
Pathophysiology
Laryngospasm
Wet Drowning
Dry Drowning
80%
20%
Hypoxemia

Acidosis

End organ damage

Cardiac Arrest
Near Drowning
Fresh water
Salt water
No difference

Surfactant is destroyed

Alveolar instability

Atelectasis &  Compliance & Bronchospasm

V/Q mismatch

Hypoxia
Drowning / Near drowning
 Drowning : is defined as death 2nd to asphyxia while immersed in a
liquid within 24h of the submersion.
 Near Drowning: is defined as immersion episode of sufficient severity
to warrant medical attention, with potential morbidity or mortality.
 Drowning is 2nd to MVA as cause of Death in children
Submersion Outcome in Children
 35% fatal
 11% severe neurologic sequelae
 33% some degree of CNS damage
Protecting Factors
Diving reflex
Hypothermia
Rescucitation & CPR within 10 minutes
Factors Bad Prognosis
 No consensus / No proven scale
 Examples …
 Delay in CPR > 10 min.
 Severe acidosis
 Coma in ED
 Asystole in ED
 Fixed dilated pupils
 Hyperkalemia > 10 mmol/L
R/o Associated Causes
Trauma ( C-spine)
Child abuse (bathtubs)
Suicide & Homicide
Myocardial Infarction & Cardiac Arrest
Dysbarism
Seizure disorder
Diabetes & Hypoglycemia
Substance abuse & poor judgment
Hypothermia
Complications
Pulmonary Injury
Secondary Drowning « ARDS»
Secondary infection
CNS Injury
 Primary & Secondary
Acute Tubular Necrosis
Secondary to Hypoxemia & Acidosis
Hypothermia
Cardiac Dysrythmias
Case
Young 19 yr old male just broke up with his girlfriend
at the city pool. He does not know how to swim
and decides to throw himself in the water. He goes
down and after a few minutes he is taken out.
He swallowed a lot of water, vomited, is coughing
and wheezing.
When is it safe to discharge ?
Asymptomatic
Normal Chest X-Ray
Normal Blood Gas
Normal Renal function
Sat.> 95% & 6 - 8 hr of observation
Caution : asymptomatic can still be hypoxic
Management
 Aggressive respiratory treatment
 CPaP / Bi-PaP / 100% O2
 Early intubation if
 Hypoxia persists
 pO2 < 70 mmHg or < 80 mmHg child with 100% O2 face mask…
 Address Bronchospasm & ARDS
 Address Hypothermia…
Prevention
 Children supervision
 CPR courses to families with pools
 Boating sobber & lifevests
 Diving injuries
 Caution: CAD / Seizure / Diabetics
Take Home ...
 Global hypoxic-ishemic event involving brain, lungs
and heart …
 No difference Fresh or Salt water ...
 No prognostic scale is accurate to predict outcome
...
 Aggressive pulmonary support ...
Take Home ...
 Global hypoxic-ishemic event involving brain, lungs
and heart …
 No difference Fresh or Salt water ...
 No prognostic scale is accurate to predict outcome
...
 Aggressive pulmonary support ...
Thank you !!!
Ottawa Base Hospital Program