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Prehospital care in acute poisoning

How far should we go ?

Philippe E.R.. Lheureux, MD, PhDDepartment of Emergency Medicine

Erasme University Hospital & French Hospital, Brussels

Background

• « Fewer than 1% of people who present with self poisoning develop severe clinical effects. One of the main challenges in managing poisoned patients is to identify this group as early as possible so thatappropriate supportive, and if necessary, specificmanagement steps can be instituted to prevent seriouscomplications. »

• A L Jones, P I Dargan. Advances, challenges, and controversies in poisoning. Emerg Med J 2002;19:190–191

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Morbidity and mortality of acute poisonings

From V. Danel

Acute poisoning, a dynamicprocess

Worsening ofsymptoms

Free interval

Possible death

Possible sequelae

Recovery

Time

exposure

24 to 72 h

From V. Danel

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Functional or lesional toxicity

FunctionalEx: cardiotropic drugs

LesionalEx: paracetamol

Blood concentrationClinical severity

Role of prehospital emergency care

• Decreasing the « free medical interval »– Diagnosis or approximation

of diagnosis– Evaluation of severity,

recognition of risk factors– Stabilisation (supportive

care)– Treatment (specific

measures)– Prevention of early

complications– Orientation (hospital, unit)

• As early as possible

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When to send a MECU ?

• Severity assessment– Toxicant(s), associations– Ingested dose / toxic dose– Formulation (slow release or not)– Patient (age, comorbidity)– Time from exposure, spontaneous vomiting,

initial management– Complications

Dispatching issues• Various dispatching

system: physicians, nurses, EMTs

• Various response levels: SMUR/UMH, notartz, SOS médecins, nurses, paramedics, EMT, firebrigade…

• Sometimes in coordination with PCC

• Severity evaluation scores– IPCS (PCC, a posteriori)– ETC score (SAMU, France)

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The French ETC score

Leveau P. Normand R.- Les appels pour tentative de suicide par intoxication médicamenteuse aiguë. Revue des SAMU 1992; 20:159-66.

The French ETC score

Leveau P. Normand R.- Les appels pour tentative de suicide par intoxication médicamenteuse aiguë. Revue des SAMU 1992; 20:159-66.

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ETC Score• P. Leveau. Le score ETC: indice de gravité des appels pour

intoxication médicamenteuse volontaire: étude prospective multicentrique (The ETC score: score for the management of emergency calls for suicidal attempts with drug: multicentreprospective study) JEUR 1994; 7: 132-8.

• Epidemio/toxico/clinical score:– Severity assessment of emergency calls to medical dispatching– Decision to send a MECU

• Prospective evaluation in 10 EMS (SAMU) of 6 French regions during 6 months – 1307 cases– sensitivity: 0,94, specificity: 0.86, PPV: 0,63, NPV: 0,98– cost-effective tool

Early stabilisation

• CPR• Airway permeability, oxygen, respiratory

support• Fluids, vasoactive agents• Control of arrhythmias• Correction of hypoglycaemia• Control of convulsions• Control of hypothermia / hyperthermia

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Specific measures

• Decontamination– Eyes, mucous membranes, skin– GI tract

• Antagonisation of toxic effects– Symptomatic agents (supportive care)– Specific agents (antidotes with toxicodynamic effect)

• Enhancement of elimination– Corporeal: diuresis, enterodialysis– Extracorporeal: haemodialysis/filtration,

haemoperfusion…– Specific agents (antidotes with toxicokinetic effect)

Specific measures

• Decontamination– Eyes, mucous membranes, skin– GI tract

• Antagonisation of toxic effects– Symptomatic agents (supportive care)– Specific agents (antidotes with toxicodynamic

effect)• Enhancement of elimination

– Corporeal: diuresis, enterodialysis– Extracorporeal: haemodialysis/filtration,

haemoperfusion…– Specific agents (antidotes with toxicokinetic effect)

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Eye / skin decontamination• As early as possible• Powdered chemicals

should be brushed off skin and clothing

• Removal of clothing, watches, rings…

• Water is widely availableand adequate in (almost) all cases as first decontamination agent: 10/15 rule

• More specific measuresmay be required after the first decontamination– ex. fluorhydric acid burns �

Ca gluconate soaks or gel

The 10/15 rule

•cold water 10-15°C•at least 10-15 min (acids)•under running water (10-15 cm)

GI tract decontamination

• Emesis induction: obsolete• Gastric emptying: removal of toxic fluids• Gastric lavage: rare indications / not

recommended in the unsafe prehospitalconditions

• Prehospital administration of single dose activated charcoal (SDAC) by MECU / ambulance staff

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Prehospital SDAC• Karim A, Ivatts S, Dargan P, et al. How feasible is it to

conform to the European guidelines on the administration of activated charcoal within one hour of an overdose? Emerg Med J 2001;18:390–2.

• Difficulties in administering SDAC to acutely poisoned patients within an hour of drug ingestion highlighted by several authors

• Ambulance technicians, paramedics or MECU may reach the overdosed patient within the first hour, but the golden hour has often passed since time is spend for– transfer to hospital– triage procedures– time waiting to see a doctor

• SDAC should be administered in the prehospitalenvironment

Prehospital SDAC

• Review of ambulance report formsand case notes in all patients presenting to A&E by ambulance after self poisoning / standardisedabstraction form. – 201 patient records /26 excluded

(incomplete data) – median time between ingestion and

pick up by an ambulance crew was77 minutes (140 minutes for the time to assessment by medicalstaff)

– 73 patients picked up by an ambulance within 1 h of overdose, only 11 (15%) of these were seenby medical staff within 1h.

– 49/73 patients would have been suitable candidates to receiveactivated charcoal.

S Thakore, N Murphy. The potential role of prehospital administration of activated charcoal. Emerg Med J 2002;19:63–65

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Prehospital SDAC• Crockett R, Krishel SJ, Manoguerra A, et al. Prehospital use of

activated charcoal: a pilot study. J Emerg Med 1996;14:335–8.• Allison TB, Gough JE, Brown LH, et al. Potential time savings by

prehospital administration of activated charcoal. Prehosp EmergCare 1997;1:73–5.

• Wax PM, Cobaugh DJ. Prehospital gastrointestinal decontaminationof toxic ingestions: A missed opportunity. Am J Emerg Med 1998;16:114–16.

• G K Isbister, A H Dawson, I M Whyte. Feasibility of prehospitaltreatment with activated charcoal: Who could we treat, who shouldwe treat?. Emerg Med J 2003;20:375–378.

• Alaspaa AO, Kuisma MJ, Hoppu K, et al. Out of hospitaladministration of activated charcoal by emergency medical services. Ann Emerg Med 2005;45:207–12.

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Prehospital SDAC Crockett R, 1996

• Pilot study evaluating the administration of AC to poisoned patients in the ambulance prior to arrival in the ED.

• Retrospective review of EMS run sheets and ED records of poisoned patients during a 6 months period from two area hospitals.

• Cases were identified that met criteria for the prehospitaladministration of AC.

• 2 groups: – 14 cases / prebospital AC– 22 cases that would have qualified to receive prehospital according

protocol /no prehospital AC for whatever reason / AC after arriving in the ED

• Results:– Average ambulance transport times: NS (12.4 min (5-21, SD 4.47) vs

9.6 min 3-17, SD 4.83), p = 0.086– Average time from first encounter with paramedics to adrnlnistration of

AC: 5.0 min (1-16, SD 3.86) vs 51.4 min (13-115, SD 21.86), p<0.0001– Tolerance: NS (1 refusal vs 2 vomiting and 2 refusal)

Prehospital SDAC G K Isbister, 2003

• Feasibility and potential risk / benefit of prehospital administration of AC• Review of deliberate self poisoning presentations to the ED of a toxicology

unit by ambulance over 6 years (standardised prospective database)• 2041 poisoning admissions • Median time to ambulance attendance: 1 h 23 min (IQR 37 min–3 h) • Median time to ED attendance: 2 h 15 min (IQR 1 h 25 min–4 h). • 774 cases (38%): ambulance attendance <1 h, 161 (8%) ED attendance < 1

h– 55 non-sedating, highly toxic substances: 24 (23 with GCS>14) with ambulance

attendance, and 5 with ED attendance, < 1 h; +18 (benefit)– 439 less toxic, sedative agent: 160 with ambulance attendance, and 32 with ED

attendance < 1 h. +128 (unuseful risk)• More patients could potentially be decontaminated if all patients attended by

ambulance within one hour received AC. • This would expose 128 patients with sedative, low risk poisonings to the risk

of aspiration, and only treat 18 extra high risk poisonings. • The small potential benefit of prehospital AC is unlikely to justify the

expense in training and protocols required to implement it

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Prehospital SDAC• S L Greene, M Kerins, N O’Connor. Prehospital activated charcoal:

the way forward. Emerg Med J 2005;22:734–737.• Attitudes of ambulance NHS trusts to recent recommendations that

the administration of SDAC should be considered as a prehospitaltherapy.

• Postal questionnaire ; response rate 92%• None of the trusts that responded provides prehospital SDAC as an

intervention. • Common barriers

– lack of evidence in the medical literature proving it is effective in improving patient outcome

– lack of a recognised protocol for its administration– concerns regarding potential complications– ambulance turnaround times– lack of availability of SDAC– lack of funding.

Conclusion: prehospital SDAC• Activated charcoal (AC) is most effective when

administered soon after the ingestion of certain substances.

• Delays are recognized to occur at times in the administration of AC after arrival of poisoned patients in the emergency department (ED).

• These delays may be avoided if AC administration isbegun in selected patients by EMS teams at scene or while en route to the ED– Earlier administration– Feasability: training needs according to EMS team /

recommendations have been produced for use by lay people athome

– Safety : potential risk of inducing vomiting and aspiration needsfurther evaluation

– Poor compliance

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Antidotes• Guidelines for hospital/ED availaibility: IPCS, US, UK,

F/B experts: poor compliance• No specific guidelines for prehospital availability (except

in F): likely to be a subset of antidotes needed in the ED• Criteria

– Early lifesaving value, no alternative (temporary) measure– Distances ant time to transport to hospitals– Frequency / probability of use

• incidence of poisonings that may require the antidote• social and economic activities of the region that may be associated

with a risk of such poisoning– Storage conditions, shelf life– Ease of use, contraindications, adverse effects � � skills– Cost, including wastage of out of date products– Possible need in mass casualities (strategic storage)

IPCS classes• 3 classes

– immediately (within 30 min) • stocked at all hospitals, as well as in health centres or doctors'

surgeries if the nearest hospital is some distance away• may also be necessary at places of work for use under medical

supervision (e.g. in factories using cyanide)– within 2 hours

• stocked at certain main hospitals; patients can be taken to thesehospitals for treatment or the antidotes can be transported - withinthe time limit - to the health facilities at which treatment is provided

– within 6 hours.• stocked at central regional depots, provided that there are adequate

facilities for transporting them within the time limit• For all categories of antidotes, there is the further option

of keeping a small amount, sufficient to start treatment, in stock locally, further supplies being obtained from a central source as required.

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Pronczuk de Garbino J, Haines J, Jacobsen D, Meredith T. Evaluation of antidotes: Activities of the International Programme on Chemical Safety. J Tox Clin Toxicol 1997;35:333-43.

BIT - Publication du Centre de Toxicologie du Québec et du Centre Anti-Poison du Québec

US, 2000

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US, 2000: antidotes within 1 h• NAC• Antivenin Crotalidae• Atropine sulfate• Ca gluconate or chloride• Cyanide kit• Desferoxamine mesilate• Digoxin immune Fab• Dimercaprol• Ethanol• Flumazenil (?)• Fomepizole

• Glucagon• Methylene blue• Naloxone hydrochloride• Physostigmine salicylate• Pralidoxime chloride• Pyridoxine• Sodium bicarbonate

US, 2000: antidotes within 1 h• NAC• Antivenin Crotalidae• Atropine sulfate• Ca gluconate or chloride• Cyanide kit• Desferoxamine mesilate• Digoxin immune Fab• Dimercaprol• Ethanol• Flumazenil (?)• Fomepizole

• Glucagon• Methylene blue• Naloxone hydrochloride• Physostigmine salicylate• Pralidoxime chloride• Pyridoxine• Sodium bicarbonate

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UK, 2006• BAEM & Guy’s Hospital, 2006• 3 categories

– Immediately available within A&E Dpt. – Available within the hospital for use within 1-4 h – Not critically time dependent or used rarely; can be held supra-

regionally. • Details of the quantity of antidote required to treat an

average adult for 24 hours to help hospitals determinethe stock they should be holding, depending on the local epidemiology of poisoning

• Poisonings in which discussion with a poisons unit isstrongly recommended

French / Belgian experts, 2006-7

• Some recommendations can be derivedfrom:– Encyclopédie Médico-chirurgicale, Médecine

d’Urgence (Elsevier)– Conférence d’experts de la SRLF

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Prehospital availability of antidotes

• French recommendations:– Petit P. Antidotes, antagonistes et épuration des toxiques en

préhospitalier. 7ème Symposium de Réanimation Préhospitalièrede Montluçon, Rev. SAMU: 1997: 61-7.

– Adrenaline, atropine, dobutamine, hypertonic glucose, gluconate ou chlorure de Ca gluconate or chloride, isoprenaline, propranolol

– Naloxone, flumazenil, hydroxocobalamine, thiosulfate, activatedcharcoal

• Poorly observed– Lapostolle F. et al. Disponibilité des antidotes dans l’aide

médicale urgente. Presse Med 2001; 30: 159-62.

Availability of antidotes in French emergency medical aid units

Lapostolle et al, 2001• Phone inquiry / physician or nurse / 102 SAMU

Metropolitan France• Availability of 37 antidotes / 4 possible response:

available in the MECU vehicle, available at the SAMU center, available in the hospital (ED, ICU, pharmacy), not available or unknown

• Results

Propranol 24/102Na bicarbonate de sodium 97/102

Activated charcoal 22/102Naloxone 95/102

Hydroxocobalamine 24/102Dobutamine 98/102

Mg sulfate 66/102Isoprenaline 100/102

Na lactate 77/102Hypertonic glucose (101/102)

Flumazenil 83/102Atropine 102/102

Ca salts (chloride or gluconate) 89/102Epinephrine 102/102

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Which antidotes are actually used ?

• French surveys: 3 � 10 % of cases– Dherbecourt V. Indication d’administration des antidotes sur les

lieux d’intervention ou pendant les transferts par le SAMU. Thèse Université de Lille, 1993

– Lardeur et al. Régulation et prise en charge des intoxications volontaires par un SAMU. Presse Medicale 2001; 30: 626-630.

– Labourel et al. Analyse épidemiologique des intoxications médicamenteuses volontaires aiguës: prise en charge par un SMUR. Rev Med Liège 2006:61: 3: 185-189.

• Glucose, naloxone, flumazenil, sodium bicarb/lactate, cyanide kit, oxygen

• Anecdotal: atropine, glucagon, Fab antidigoxine, fomepizole or ethanol, adrenaline/diazepam, NAC

Hypertonic Glucose• Indicated for hypoglycemia.• Hypoglycemia results from:

– Excess insulin dose– Inadequate calories following normal insulin / SUA dose

• Incidence of bonafide hypoglycemia in adults who do not have diabetes mellitus is exceedingly rare.

• Causes include:– Very extreme stress states– Insulinomas– Intoxication with certain drugs (beta blockers, ethanol,

salicylates…)• Babies and young children should be approached with a

higher index of suspicion (stress, infection,…)

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Hypertonic Glucose• Reasoning behind empiric administration of

hypertonic glucose has been that irreversible brain damage may result from delays in treating hypoglycemia.

• Also based on assumption that glucose is harmless to persons with normal or elevated blood glucose levels

• Research has shown that people who receive glucose solutions before or during episodes of brain ischemia tend to have more significant neurological damage when compared to patients who only received saline solution

Hypertonic Glucose

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Hypertonic Glucose• Administering a large glucose load during

periods of ischemia floods the brain with glucose molecules that are converted to pruvate, then lactate.

• Localized acidosis can cause neurological damage to delicate brain tissues

• Glucometers to rapidly assess blood glucose levels should be available in every EMS unit

• When in doubt—give 50% glucose (but try not to be in doubt!)

Naloxone• Used for reversal of respiratory depression associated

with opiate / opioid overdose.• Narcotic overdose should be fairly easy to recognize in

the field setting: miosis, respiratory depression, CNS depression, needle tracks…

• Goal of prehospital naloxone therapy is to simply reverse respiratory depression.– Overzealous administration will induce full-blown narcotic

withdrawal that will be very unpleasant for all involved– Be careful for associated drugs (“speedballs”)

• Should only be administered in small, diluted and titrated doses

• Short duration of action• Alternative routes (ex. intranasal)

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Flumazenil• Benzodiazepine antagonist• Many people are benzodiazepine-dependent.

– Sudden reversal with flumazenil can cause a dangerous benzodiazepine withdrawal: tremors, high levels of anxiety, muscle jerks, seizures

• Many people co-ingest other drugs– Sudden reversal with flumazenil can unmask convulsions,

arrythmias,…• Diagnostic value, accidental poisoning in children• Should only be administered in small, diluted and

titrated doses• Short duration of action

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No more coma cocktail !• Some have advocated giving

several drugs to all unconscious patients of unknown etiology :– Thiamine– 50% dextrose– Naloxone– Flumazenil

• Any EMS person with even a small amount of field experience should be able to narrow down the potential causes of unconsciousness without administering “diagnostic medication.”

Bryan E. Bledsoe,Midlothian, TexasPrehospital Pharmacology:A Common-Sense Approach

Na salts (bicarb / lactate)

• Na channel blockade: « membrane stabilizing effect »

• Indications:– Widening of QRS complex– Arrhythmias– Hypotension– Convulsions (?)

• Alternative: Na lactate

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Cyanide antidote kits

Cyanide antidotes• Taylor’s kit: metHb inducer(s) (amyl nitrite, sodium nitrite,

4-DMAP) + thiosulfate– Cheap– Reduction of oxygen carrying capacity (! HbCO)– Hypotension

• Dicobalt Edetate (Kelocyanor®)– Relatively cheap– “Reciprocal antidote”: hyper/hypotension, arrhythmias– Mass CN exposure casualities (industrial, terrorism) ?

• Hydroxocobalamine +/- thiosulfate– Expensive– Safe (skin/urine discoloration, rare hypersentitivity)– Abnormalities in colorimetric laboratory tests– First choice if empiric use (uncertain CN poisoning) or smoke

exposure

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OP/Nerve agents antidotes

• Atropine:– Very high doses are required (stragegic storage:

hospitals, army)– Risk of multiple casualities (Sarin, Tokyo Metro, 1997)

• AChE reactivators: pralidoxime / obidoxime• Diazepam• Autoinjectors:

– NAAK – Mark-1 autoinjectors– Diazepam autoinjectors

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Orientation of the patient

• Hyperbaric oxygen chamber (mono/multi)• Active elimination (HD, CHF, HP,…)• Heavy support therapy

– Refractory shock, respiratory failure (refractoryhypoxemia), renal failure,…

– Extracoropeal circulatory assistance, MARS, livertransplant ,…

• Some antidotal therapies (availability, management)

• Surgery (caustic ingestions), burn center…

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Take home message

• Prehospital care may be life saving for somepoisoned patients !

• Need for adequate dispatching of medicalemergency calls

• Prehospital decontamination should not be a problem in Belgium

• Only a few antidotes are needed in the MECU vehicles, but the teams should be trained to use them properly

• An agreement is needed regarding whichpatients need specific hospital orientation, to save time, money and lives.

Many thanks for your attention !

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