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Environmental MedicineEnvironmental Medicine

Carbon Monoxide PoisoningCarbon Monoxide PoisoningBarotraumaBarotrauma

Caisson DiseaseCaisson Disease

Don Hudson, D.O., FACEP/ACOEPDon Hudson, D.O., FACEP/ACOEP

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Introduction Introduction

Medicine related to physical Medicine related to physical phenomenaphenomena

Barotrauma and temperatureBarotrauma and temperature But first, carbon monoxide poisoningBut first, carbon monoxide poisoning Consider Mass InjuriesConsider Mass Injuries

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Carbon monoxideCarbon monoxide

Colorless, odorless tasteless non-irritant Colorless, odorless tasteless non-irritant gas from incomplete combustion of gas from incomplete combustion of organic materialsorganic materials

1-2% COHb in non-smokers, 5-6% in 1-2% COHb in non-smokers, 5-6% in smokers.smokers.

Approx. 1,000 people die /year from CO Approx. 1,000 people die /year from CO poisoning. Less now natural gas has poisoning. Less now natural gas has replaced coal gas.replaced coal gas.

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ToxicityToxicity

1985 - 1365 deaths - 475 admissions & 1985 - 1365 deaths - 475 admissions & 10 deaths in hospitals in the UK.10 deaths in hospitals in the UK.

3800 die per annum in US3800 die per annum in US > 10,000 days at work lost> 10,000 days at work lost Main cause of death in childrenMain cause of death in children Recent deaths in AnchorageRecent deaths in Anchorage

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ToxicityToxicity

Common sourcesCommon sources• car exhausts (lethal in closed garage in car exhausts (lethal in closed garage in

<10 min) (NB catalysts)<10 min) (NB catalysts)• Unserviced heating systemsUnserviced heating systems• Fires - all sortsFires - all sorts• Methylene chloride (paint stripper)Methylene chloride (paint stripper)• Some types of insulationsSome types of insulations

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PhysiologyPhysiology

Binds to Hb with an affinity 200-250 times that of Binds to Hb with an affinity 200-250 times that of oxygen.oxygen.

Forms carboxyhemoglobin, reducing the total oxygen-Forms carboxyhemoglobin, reducing the total oxygen-carrying capacity of blood and shifting Ocarrying capacity of blood and shifting O2 2 dissociation dissociation

curve to the left.curve to the left. Alters shape of Hb molecule making it less ready to Alters shape of Hb molecule making it less ready to

release Orelease O2.2.

Binds to cellular proteins e.g. cytochrome oxidase Binds to cellular proteins e.g. cytochrome oxidase similarly to cyanide.similarly to cyanide.

t½t½ 250 min in air 250 min in air

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Clinical manifestationsClinical manifestations

VariedVaried Depends on Depends on

• CO concentrationCO concentration• length of exposure length of exposure • general health of exposed persongeneral health of exposed person

Infants, elderly, CVS disease, anemia, Infants, elderly, CVS disease, anemia, lung disease and patients with increased lung disease and patients with increased metabolic rate are at riskmetabolic rate are at risk

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Chronic exposure to low Chronic exposure to low concentrationsconcentrations

Headache, fatigue, dizziness, difficulty Headache, fatigue, dizziness, difficulty in concentration, paraesthesia, chest in concentration, paraesthesia, chest pain, palpitations, visual disturbances, pain, palpitations, visual disturbances, nausea, diarrhea, abdominal pain.nausea, diarrhea, abdominal pain.

Can easily be mistaken for other Can easily be mistaken for other illnesses.illnesses.

Should be considered in vague Should be considered in vague presentations.presentations.

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Acute poisoningAcute poisoning

Clinical findings do NOT correlate well Clinical findings do NOT correlate well with CO concentrationswith CO concentrations

<10% - asymptomatic<10% - asymptomatic 10-30% - headache, mild exertional 10-30% - headache, mild exertional

dyspnea, “gastro-enteritis”.dyspnea, “gastro-enteritis”. Coma, seizures, cardiorespiratory arrest Coma, seizures, cardiorespiratory arrest

if >60%if >60% Live patients are pale, NOT pink.Live patients are pale, NOT pink.

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Neuropsychiatric problemsNeuropsychiatric problems

InsidiousInsidious Intellectual deterioration, memory Intellectual deterioration, memory

impairment, Parkinsonism, akinetic impairment, Parkinsonism, akinetic mutism; damage to any area but mutism; damage to any area but especially globus pallidus, cerebral especially globus pallidus, cerebral cortex, hippocampus and substantia cortex, hippocampus and substantia nigra. nigra.

Personality changes - not for betterPersonality changes - not for better

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TreatmentTreatment

Remove from sourceRemove from source 100% 100% OO2 2 by close-fitting facemask - intubate by close-fitting facemask - intubate

and ventilate EARLY if unconscious as high and ventilate EARLY if unconscious as high incidence of regurgitation is present. incidence of regurgitation is present.

Dissociation from Hb occurs readily - Dissociation from Hb occurs readily - elimination t½ <50 min with 100elimination t½ <50 min with 100% % OO2 2

Hyperbaric treatment at 2.5bar reduces this Hyperbaric treatment at 2.5bar reduces this to 22 minutes and dissolves enough Oto 22 minutes and dissolves enough O2 2 to to

meet needs of body without Hb.meet needs of body without Hb.

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Results of hyperbaric therapyResults of hyperbaric therapy

First used successfully in Glasgow in First used successfully in Glasgow in 1960s.1960s.

Reduces morbidity from 43% to <5%.Reduces morbidity from 43% to <5%. Can even be used in late-presenting Can even be used in late-presenting

cases with high CO levels.cases with high CO levels. Early treatment associated with better Early treatment associated with better

outcomesoutcomes General support also necessary. General support also necessary.

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Hyperbaric TherapyHyperbaric Therapy

Currently there is no medical facility, in Currently there is no medical facility, in Anchorage, equipped to do this.Anchorage, equipped to do this.

There is only one outside vendor There is only one outside vendor available to perform this service.available to perform this service.

The staffing of the chamber is a major The staffing of the chamber is a major problem.problem.

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Blast injury Blast injury

6 separate mechanisms of 6 separate mechanisms of injury:injury:• Blast wave. Transient high Blast wave. Transient high

pressure wavepressure wave– Cellular disruption at air-tissue Cellular disruption at air-tissue

interface interface • perforated eardrum at +1barperforated eardrum at +1bar• ““blast lung” at +1.75 barblast lung” at +1.75 bar• shearing at tissue planes - shearing at tissue planes -

submucosal/serosal bleedsubmucosal/serosal bleed• sudden expansion of compressed sudden expansion of compressed

trapped gas in bowel or blood trapped gas in bowel or blood vessels leading to perforation or air vessels leading to perforation or air embolismembolism

• Blast lung often delayed up to 48 Blast lung often delayed up to 48 hourshours

• Rare in survivors (0.6%)Rare in survivors (0.6%)

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Blast injury mechanismsBlast injury mechanisms

Blast windBlast wind• In the immediate vicinity will fragment bodiesIn the immediate vicinity will fragment bodies• Further away will produce blast limb Further away will produce blast limb

avulsionsavulsions• Blast transportation leading to secondary Blast transportation leading to secondary

impact injuriesimpact injuries• Injuries from flying debris/secondary missiles Injuries from flying debris/secondary missiles

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Blast injury mechanismsBlast injury mechanisms

MissilesMissiles• Bomb fragments (casing, elements Bomb fragments (casing, elements

deliberately included - nuts, nails, ball-deliberately included - nuts, nails, ball-bearings)bearings)

• Secondary missiles picked up by blast Secondary missiles picked up by blast wind; glass, pieces of vehicles etcwind; glass, pieces of vehicles etc

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Blast injury mechanismsBlast injury mechanisms

Flash burnsFlash burns Crush injuries - from falling masonry, Crush injuries - from falling masonry,

pieces of vehicle etcpieces of vehicle etc Psychological effects - particularly with Psychological effects - particularly with

terrorist weapons.terrorist weapons.

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Blast injury treatmentBlast injury treatment

ABC - but try to avoid ventilating ABC - but try to avoid ventilating patients with lung injurypatients with lung injury

Care with extremities crushed for Care with extremities crushed for prolonged periodsprolonged periods

Preserve all and any debris and its Preserve all and any debris and its location for forensic analysislocation for forensic analysis

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Caisson disease- Bends Caisson disease- Bends

Gas dissolves in blood in proportion to Gas dissolves in blood in proportion to ambient pressure.ambient pressure.

Rapid reductions in pressure cause bubbles Rapid reductions in pressure cause bubbles to form in the tissuesto form in the tissues

Risk factors: multiple dives, rapid ascent, Risk factors: multiple dives, rapid ascent, poor discipline & flying homepoor discipline & flying home

Presents 1-36 hours later - can be anywhere Presents 1-36 hours later - can be anywhere in the world in the world

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Presentations of Caisson diseasePresentations of Caisson disease

Throbbing muscle and joint painThrobbing muscle and joint pain Migrating skin mottling/rashesMigrating skin mottling/rashes Coughs and chest painCoughs and chest pain CNS signsCNS signs

• headacheheadache• seizuresseizures• deafness/ nystagmusdeafness/ nystagmus• mood changesmood changes

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Treatment of Caisson diseaseTreatment of Caisson diseaseor BENDSor BENDS

Act rapidlyAct rapidly Avoid aspirin and opiatesAvoid aspirin and opiates Recompress urgently.Recompress urgently. Recompression <30min after onset of Recompression <30min after onset of

symptoms >80% respondsymptoms >80% respond After 6hour delay 50% respondAfter 6hour delay 50% respond Fly (Cab Alt)as low as practicableFly (Cab Alt)as low as practicable

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SummarySummary

CO seasonCO season Blast and pressure Blast and pressure

diseasedisease Comments?Comments? Questions? Questions?