vandaag 13 jaar geleden

19/09/2014 Wetteren case 1

Patient Management of the Acrylonitrile-Disaster in Wetteren

I. Demeyer, MD, An, CCM Onze Lieve Vrouw Hospital

Aalst, Belgium

Some hints and pitfalls about..

• Beginners mistakes

• Communication errors

• “Waste of money”- story

• (non?)-experience experts

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This presentation only reflects the author’s personal opinion and neither the official

report nor public authority

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Not every presentation is successful

Definitions

• Disaster

• Disaster Relief Team

– Tasks of medical task force

• CP- Ops

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Disaster ?

• Starts with the ‘perception’ of a disaster

• Retrospective view of the event(s)

The Dendermonde day care center ‘Fabeltjesland’ assault

(jan 29, 2009) – 10 victims

– But 5 medical teams at the scene < 20 min

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8

Wetteren

Disaster or not?

“An occurrence of a natural catastrophe,

technological accident, or human caused

event that has resulted in severe property

damage, deaths, and/or multiple injuries.” USA Federal Emergency Management Agency (FEMA)

NOT: 1 death and 1 severely injured victim

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Disaster or not?

“The result of a vast ecological breakdown in

the relations between man and his

environment, a serious and sudden (or slow,

as in drought) disruption on such a scale

that the stricken community needs

extraordinary efforts to cope with it, often

with outside help or international aid.” WHO definition

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Wetteren case a Disaster?

YES

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Disaster Relief Team in Belgium

Team Discipline 1: Fire Dept

Discipline 2: Medical Dept

Discipline 3: Police Services

Discipline 4: Technical Support Services

Discipline 5: Communication Services

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Disaster Relief Team in Belgium

Discipline 2

Medical Dept.

East Flanders

4 Medical Directors

16 Deputy Medical Directors

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Discipline 2

Medical Director

At the scene

CP-Ops: operational command center

Co-organizer of the disaster relief with specific attention towards the safety (mental & physical) of all rescueworkers, the care for the victims and the population …

Reports to the Crisis Center (Provincial), (representative of the Government Discipl 2)

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Discipline 2: Medical

Victims

Implicated, not wounded

Population Wetteren, Schellebelle, Serskamp, Wichelen, …

Rescue workers (fire dept., civil protection, police services …)

Wounded

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Victims

Duration & number

19 days (May 4 – 21) provincial phase

1.979 evacuated civilians

(May 18: “all – 1” habitants < 250 m back home)

1 dead victim

397 hospital visitors

1 severely injured victim (case report)

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Time Lines

May 4 2 a.m.: Derailment and fire of train

9:42 a.m.: high values arylonitrile in sewer system

May 7 7 a.m.: High values acrylonitrile in sewer system miles away ….

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First communication

2:02 a.m. “Locomotive on fire”

2:08 a.m. 7 fire men at the scene

In the middle of nowhere: no access possible

Communication Cut the power transmission lines

Up scaling “fire dept.” zonal alert

Evacuation of neighborhood (150 m)

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Victims

2:00 a.m. Evacuation perimeter 150 m

± 300 people (towards festival hall and fire station)

Based on? Explosion risk?

Toxic – chemical risk?

Gut feeling

2:45 a.m. Decision taken at “hood mutual agreement” (discipl 1,2 &3)

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Decision making

• Based on:

– Hazardous substance database:

http://toxnet.nlm.nih.gov/

• Intikken: acrylonitrile

• HSDB als keuze aanklikken

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Evacuation

‘no worries…’

‘no worries, it’s all right ‘

First Communication

Police: summons people to leave their house from door to door & P.A.

But “feelings” within policemen

People refuse to leave their house!

Discussion vs. urgency

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Safety circles

CP-Ops

Decision making

Based on textbooks, databases,

Based on experience (Toxicologists!!)

Acrylonitrile: toxicity

Tri-Ethyl-Aluminium explosion risk

Ethylaluminiumdichloride

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explosion risk

28

Airway protection??

Acrylonitrile

(monomere in polymereproduction: lego)

At room temp: good water soluble

Mixture with air: highly explosive

Highly exothermic reaction during polymerisation

Density > air Sewing system, waterholes, lowlands

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Acrylonitrile

Skin, inhaled (toxic level < smell border)

Short T 50% (20 min) quickly eliminated, metabolised to cyanide

Incomplete combustion HCN

Respiratory protection for rescue workers

Hazmat equipment

Urgent need for antidote (Cyanokit®)

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Cyanide intoxicatie

• Waterstofcyanide (HCN): acute cyanide intoxicatie

• Aanpak/Therapie?

– Geen internationale richtlijnen

– EuSEM:

• pre & in-hospitaal richtlijnen

• literatuurreview

Europese consensus 2013

HCN

• Polyurethaan

• Verf, acryl

• Nylon

• Plastiek

• Papier,hout, wol,katoen

May 4

02:02 a.m. Call from 112 to fire dept. Wetteren

02:08 a.m. Fire dept. at the scene

02:14 a.m. Upscaling for fire dept. alert

Medical disaster plan initiated

02:45 a.m. Council phase

03:40 a.m. Provincial phase

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CN intoxicatie

• Afhankelijk van wijze van besmetting, concentratie en duur van blootstelling

• LD50 = 1mg/kg

• Ingestie

• Transdermaal

• Rookinhalatie bij brand (4-12u later cyanide)

CN

• 1704: Pruisisch blauw: synthetisch pigment (ijzer(III)hexacyanoferraat(II))

• 1783: Blauwzuur: Vloeibaar – gasvormig vanaf 26°C

• WO II: Zyklon B • Geur van bittere amandelen

• Toepassingen anno 2014

– Metaalreiniging – Mijnindustrie (goudextractie uit erts) – Plastics industrie

CN intoxicatie

• Literatuur: blootstelling tot 14 dagen = acuut

• Acute Exposure Guidelines Levels (AEGL)

– AEGL – 1: ongemak, irritatie snel voorbijgaand

– AEGL – 2: duidelijk en ernstig gezondheidseffect

– AEGL – 3: levensbedreigend/overlijden

• Belgische werknemers: max 2 ppm/8u

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Waarden in ppm

Classificatie Duur van blootstelling

10 min 30 min 1 uur 4 uur 8 uur

AEGL – 1 4.6 4.6 4.6 4.6 4.6

AEGL – 2 290 110 57 16 8.6

AEGL – 3 480 180 100 35 19

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HCN toxiciteit

Symptomen – Mild: neurologisch/respiratoir:

• Hoofdpijn, verwardheid, duizeligheid, nausea, braken, palpitaties, tachypnee/dyspnee, amandelgeur, branderige droge keel, kersrode huid, mydriasis.

– Ernstig: neuro/resp/cardiovasculaire depressie: • Epilepsie, coma • Initieel hyperdynamisch, nadien cardiovasculair falen:

bradycardie, hypotensie, cardiorespiratoir arrest, †

† Seconden / minuten afhankelijk van blootstelling – 100 ppm: † > 60 min – 300 ppm † > sec/min

HCN toxiciteit

Cyanide ion affiniteit

1. Cobalt

2. Fe3+ in methemoglobine

3. Cytochrome aa3 oxidase mitochondriaal

4. Fe2+ in hemoglobine

Cytochrome aa3 oxidase mitochondriaal

Cytochrome oxidase:

– Op celniveau: mitochondriaal

– Hersenen/hart/lever

– Pyruvaat via acetyl-coA in aerobe Kreb cyclus ATP productie.

– Fe houdend enzyme, essentieel voor NADH

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2. HCN toxiciteit

• Niet competitieve inhibitie met cyt.oxidase Kreb //

• Pyruvaat Lactaat (anaeroob) metabole (lactaat) acidose.

• Andere mechanismen: ?

– Coronaire art VC Cardiac output zakt

– Longoedeem via onduidelijk mechanisme

• Afbraak: leverenzyme: rhodenase (S-donor): CN thiocyanaat renale

klaring

– trage reactie.

CN-

• Inhibeert 40tal enzymesystemen

• Inhibeert oxidatieve fosforylatie

– Bindt aan cytochroom aa3 oxidase

– Aeroob nr anaeroob metabolisme

• Cellulair ATP tekort: lactaatacidose

CN vs CO

Information

Exchange info between Operational Centre and Crisis Centre

6 press communications between 3:40 and 9:38 a.m.

6 a.m. first press conference

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Communication

Lack of “experience”

Crisis Centre & Operational centre

Disaster Time span, > 48 hrs vs 19 days

E 40: Gas leak pipeline rupture: 48 hrs

E 413: H2 gas transport collision: 48 hrs

Mass communication

Avoid highways during traffic jams

Decision making and political consequences

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Decision making

• 1 PPM measured: evacuation

• Case definition acrylonitrile intox:

– Mucosa irritation: proves contact acrylonitrile

– Other symptoms: metabolized towards CN

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Behandeling

• Bron wegnemen

• 100% O2

• Ondersteunende maatregelen

• Antidoot:

– Methaemoglobine vorming (nitraten, 4-DMAP)

– Sulfaatdonoren (thiosulfaat)

– Cobaltverbindingen (hydroxycobalamine)

Cyanokit

• Dosis 70mg/kg (5g) over 15-20 min, te herhalen zo arrest/aanhoudende cardiovasculaire instabiliteit. Max 10g

• 0 tot >99 jaar (max 140mg/kg in totaal), ook bij zwangerschap

• Reeds prehospitaal: zo meerdere patiënten ter plaatse: geef 2,5 g IV per persoon, restdosis in hospitaal.

• Nadelen:

– ! Valse verhoging van Hb-CO

– Niet in zelfde leiding als thiosulfaat.

– Foutieve probleemmelding bij hemodialyse (blood leak)

– Erytheem moeilijke beoordeling brandwonden nadien

Biochemie

• Cyanideconcentratie in bloed correleert zeer goed met plasmalactaat (> 90 mg/dl)

• Geen snelle detectietechniek voor HCN (bloed)

Lactaatbepaling

• Omweg om ernst HCN intox te bepalen

Lessons learned (1)

PREPARE YOURSELVE to deal with negative press/public comments

DOCUMENT / REPORT ALL EVENTS

TIME REGISTRATION

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Upscaling disaster planning

2:14 a.m. Medical Disaster Plan (MIP)

2:45 a.m. Council phase

3:40 a.m. Provincial phase

6:21 a.m. Telephone Information Centre

What kind of information?

Close doors, windows, stay inside, avoid Wetteren centre

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Lessons learned (2)

Inform your citizens a.s.a.p.

- Updates through website/Facebook/twitter/domino

- Telephone Information Centre (TIC)

. Started at 06:21 a.m.!!!

. 3000 calls/day

Update your citizens

Give correct information

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Lessons learned (3)

Towards Decision makers (Crisis center):

Don’t take your whishes for real

Message: return home

vs.

Message: Wait another day (May 9 – 12)

Local population “aggressive” towards the CP-Ops staff

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61

Home or not?

Lessons learned (4) – Case 1

“Acrylonitrile is carcinogenic”

TV news interviews Prof. XXX, MD, toxicologist at

University XXX

“No carcinogenic effects retrieved from literature”

Toxicologists at different Universities & Industrial MDs (follow up > 20 yrs.)

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Lessons learned (4) – Case 2

“Large numbers of dead fish washing up on the shores of the Schelde

downstream of Wetteren”

TV broadcasts

“Not confirmed”

By river police: waste of money, time …

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How to handle this evil?

Deny first message of carcinogenic effect?

- My answer: don’t do this

- Public opinion: “they are hiding the truth”

CC is “running behind the facts”

- Inform the news broadcasting media

- Provide them with experts able to explain “lay people” the risks

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Lessons learned (5)

Beginners mistake: when you see a camera

- Think twice before expressing your “feelings”

Circumstances

- 3 days requesting for sanitary facilities, no feedback from the CC

- May 8 visit from important politicians and the Mayors of the neighbouring villages: STOP of all activities… till 14 hrs: no decisions at the CC

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Wat hebben we vandaag geleerd?

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Lessons learned (6)

• Occupational medicine: no collaboration (Belgium)

– Fire dept: each unit has his own occup. Med.

– Fire dept: fire fight unit doctor

• Police: own medical dept.

• Civil protection

• Hospitals

• GP’s

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Lessons learned (6)

• > 20 different occupational doctors

• > 10 General practioners

Different approach in follow up:

minimizing vs maximizing

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Ongoing problems

Mr J. Haek, CEO, announces: “Infrabel will pay all costs: ship, cleaning, civilians…”

Blood collections/results: communicated “not clearly” to the public

Epidemiologic follow-up of the local population and rescue workers

Large evacuation planning

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QUESTIONS ?? (& ANSWERS …?)

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Take home

• Denk aan CN intoxicatie naast CO, ook bij minder gekende stoffen/chemische rampen acrylonitril in Wetteren

• Behandel zo snel mogelijk

– Bij grote waarschijnlijkheid van intoxicatie (brand met polymeren), tachypnee, hypotensie, bradycardie, epilepsie, cardiovasculaire collaps, cardiorespiratoir arrest.

– Veranderd bewustzijn (desoriëntatie, verwardheid, mydriasis)

– Lactaatacidose, zeker zo >8 mmol/L

• 100% O2 + antidotum: cyanokit 5g, ook pre-hospitaal., te herhalen bij aanhoudend verhoogd lactaat na controle.

Diagnose

Labo-analyse

– Sterke correlatie tussen cyanide waardes en lactaat, echter aspecifiek

– Cyanide bepaling op bloed

• Korte t ½ (60’)

• Duurt 2u in labo

– Arterieel/ Veneus bloedgas: hoge Pv02, hoge veneuze 02 sat Pa02 – Pv02 klein, echter door R/ met 100% 02 moeizame interpretatie.

Besluit:

– Behandel meteen zo

• Verdacht op CN intoxicatie: omstandigheden, veranderd bewustzijn, forse lactaatacidose

• Zeker zo bradycard/hypotens.

Behandeling

• Safety first! – Bron verwijderen.

• BLS

• 100% 02

– 1. Zowel bij vermoeden CO als CN.

– 2. Vermoedelijk directe reactivatie van mitochondriale enzymes.

• Supportief:

– Vasopressie

– Convulsieve therapie

• Antidota

– 3 types

• Hyperbare 02 geen bewezen meerwaarde

Antidota

1. Vorming van methemoglobine:

– 4 - DMAP

– Nitriten

2. S-donoren

– Natriumthiosulfaat

3. Cobaltgroepen

– Dicobaltedetaat

– Hydroxycobolamine

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HCN detoxificatie

• Conversie naar thiocyanaat

• Conversie naar cyanocobalamine (via hydroxycobalamine)

1. Methemoglobinevorming

• 4-DMAP (4-dimethylaminophenol ) / nitrieten

– Vorming van methemoglobine (Hb-Fe3+) snelle chelatie met cyanide cyanomethemoglobine trage disscociatie in cyanide omzetting via rhodenase in thiocyanaat renale klaring.

– Nevenwerkingen:

• VD met hypotensie, hemolyse, nefrotoxiciteit.

• Reeds bestaande hypoxemie + methemoglobinemie: methemoglobinemie -> centrale cyanose, dyspnee, zo > 30% Fe3+-Hb: cardiovasculaire collaps/ †.

hydroxycobalamine

• Chelator cyanide: vormt vit B 12 (cyanocobalamine), via nieren uitgescheiden

• Urticaria, huidverkleuring

• Bloeddrukstijging

• Lang halfleven (1 dosis genoeg)

• 70 mg/kg (5 gr)

2. Natriumthiosulfaat

• S – donatie: versnelt rhodenase x 3: acceleratie van enzymwerking/renale klaring.

• Eerder add-on therapie: werkt traag, add-on bij 1 of bij 3.

• Dosis: 12,5g traag IV (0,5g/kg IV)

3. Cobalt (Cyanokit, ...)

• Cyanide ion hoogste affiniteit voor cobalt.

• 2 vormen:

– Dicobalt edetaat: 2e lijnstherapie (anaphylaxis, vrij cobalt is toxisch)

– Hydroxycobalamine (Cyanokit)

• + cyanide cyanocobalamine (vorm van vit B12) renale excretie.

• Voordelen: – Minimale nevenwerkingen: urticaria, angioneurotisch

oedeem, uiterst zeldzaam anaphylaxis,photosensiviteit, erythema (tot 15 dagen), chromaturie (48u tot 30 dagen).

– Verminderd zuurstof-transport capaciteit niet, itt DMAP/nitriet

– NO-scavenging Hypertensie (werkt tendens tot hypotensie bij CN tegen)

– Snelle werking, vlot transport tot in weefsels.

– Veilig in hemodynamisch instabiele patiënten, bij arrest.

Welk antidotum?

• Elke regio eigen algoritmes

• In VS: 4-DMAP/nitrieten en thiosulfaat.

• Frankrijk: cyanokit, ook pre-hospitaal

• Vergelijking tussen 1 – 2 en 3: tendens tot meerwaarde voor cyanokit,

voornamelijk door sneller herstel van de MAP.

• Geen bewezen survival benefit/ invloed op metabole acidose.

• Prijs:

– cyanokit € 681 voor 2 vials van 2,5g.

– Nithiodote (Nanitriet – natriumthiosulfaat): $ 422