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PropertiesCyanide is a rapidly acting and

extremely toxic chemical that existsin various forms. Depending ontemperature, it can be a colourlessgas or liquid (e.g. hydrogen cyanide HCN, cyanogen) or a solid (e.g. sodiumor potassium cyanide). Cyanide isdescribed as having a bitter almondodour at concentrations greater than1 ppm, but not everyone can detect this.

Routes of absorptionThe primary route of occupationalexposure is through inhalation, which

results in rapid absorption into thesystemic circulation. A less commonroute in the occupational setting isthrough ingestion. Cyanide can also beabsorbed through the eyes orintact skin.

Mechanism of actionCyanide inhibits cytochrome oxidase atthe cellular level, preventing cells fromusing oxygen. This impairs the functionof vital organs.

Cyanide poisoningThe onset of symptoms followingcyanide exposure depends on:

a) the form of cyanide;b) the mode of entry into the body; andc) the dose.

Acute

Mild poisoning- This may manifest asanxiety, headache, nausea and vomiting,mucous membrane irritation, metallic

taste, shortness of breath and dizziness.

Progression of poisoning- Signsof deterioration include increasingshortness of breath, falling bloodpressure, cardiac arrhythmia, periods

of cyanosis and a deteriorating level ofconsciousness.

Moderate and severe poisoning-

Exposure to cyanide gas produces themost rapid onset of symptoms. Highconcentrations of inhaled cyanideresult in rapid loss of consciousnesswith seizures, difficulty breathing andcardiac arrest, with death occurringwithin a few minutes. Survivors maysuffer brain injury due to either a directtoxic effect or anoxia (lack of oxygen).

Eyes- Direct contact with cyanide incaustic solutions is irritating to theeyes. Cyanide can also be absorbedinto the body through the eyes.

Skin- Cyanide in caustic solution iscorrosive to the skin and can also befairly rapidly absorbed through the skin.

Chronic

Chronic exposure may result insymptoms of headache, eye irritation,fatigue, chest symptoms and nosebleeds. This is uncommon as cyanide isbroken down to thiocyanate in the bodyand excreted.

Rescue and first aidThe first priority is to remove thecasualty from further exposure ideally move to a source of fresh air.

The trained rescuer should havedonned appropriate respiratory anddermal personal protective equipment(PPE), especially gloves, goggles andan appropriate respirator if hydrogencyanide or liquid cyanide is involved.

Airway- Clear and insert oral airwayif casualty is unconscious and not

breathing. If breathing, place incoma position.

Breathing- Mouth-to-mouthresuscitation should be avoided due tothe risk of contamination to the rescuer.

If not breathing, use a resuscitationbag and mask. Provide 100% oxygenby mask with a non-return valve if

available.Circulation- Check for pulse.Commence external cardiacmassage if absent.

OxygenOxygen (100%) is considered themost useful treatment for earlycyanide poisoning and shouldbe administered to all personsconsidered exposed to cyanide,whether conscious or unconscious,

breathing or not breathing.Each site needs to undertake arisk assessmentto determine theappropriate quantity and locationof oxygen that should be availableon site, taking into considerationthe numbers of potentially exposedpersonnel and the duration to reacha tertiary care facility.

DecontaminationRemove any contaminated clothing

and ensure these items are placedin a sealed collection bag. Washdown the casualty with copiousamounts of fresh water.

Treatment should not be delayed bydecontamination procedures andshould be started immediately.

TransferArrange urgent transfer to thenearest hospital or, if remote,

nearest doctor. The casualty shouldbe accompanied by someone trainedin cardiopulmonary resuscitation(CPR) and able to continueresuscitation. The cyanide antidotekit should accompany the person.

Cyanide poisoning - first aid and medical treatment

Revised August 2007

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IngestionThere is little evidence to support thebenefit of emesis (vomiting), gastric lavageor charcoal administration, especiallywhen more than 2 hours have lapsedsince ingestion. This form of treatmentshould only be used on the advice of an

emergency physician or toxicologist.

Eye contaminationThis should be managed with copiousirrigation using water or normal salinefor at least 5 minutes.

Cyanide antidotesThe use of antidotes is not as immediatelycriticalas the administration of effectivefirst aid and life support measures.

The selected cyanide antidote should bestored in a sealed tagged container in anaccessible area with the cyanide protocolenclosed. The contents of the containerand the expiry date should be regularlychecked. Intravenous fluids and cannulaeand blood tubes should be available.The kit should be transported with thecasualty to the hospital or doctor.

Mild poisoning

Rest and oxygen may be all that is needed.

Progression

If there is evidence of deterioration,despite 100% oxygen administration, andthere is a convincing history of exposure,amyl nitrite may be used.

The advantage of amyl nitrite is that,unlike the other antidotes, it does notrequire intravenous administration andtherefore may be given by a personuntrained in intravenous line insertion.

The dosage is 0.2-0.4 ml via Ambu bag,or on gauze held under the casualtys

nose. Oxygen should continue to beadministered.

Warning: Amyl nitrite may produce asevere drop in blood pressure. Monitorblood pressure and stop the casualtyfrom standing and walking.

Moderate and severe poisoning

Continue administration of 100% oxygen.

Advanced life support may be requiredif the casualty is in shock or havingseizures, with due caution to the

protection of the care giver.

Preferably insert two intravenous lines.

Monitor heart and blood pressure, andpulse oximetry if available.

Monitor level of consciousness usingthe Glasgow Coma Scale (GCS).

Take 10 ml blood in a sodium heparin orsodium fluoride tube for blood cyanidelevels to confirm the diagnosis. Thesample should be chilled but not frozenand transferred to a laboratory capable

of undertaking cyanide measurements.Treatment should not be delayed whileawaiting test results.Note that as mostcyanide is in the red blood cells, thelevels in the blood may not accuratelyreflect the true level of free cyanideand symptoms should therefore guidetreatment.

Intravenous administration

of an antidote

Hydroxycobalamin was recentlyapproved by the U.S. Food and DrugAdministration for treatment ofcyanide poisoning, and is availablethrough the Therapeutic GoodsAdministration Special AccessScheme. It reacts with cyanide toform cyanocobalamin, which isexcreted by the kidneys.

Dose:Administer 5-15 ghydroxycobalamin intravenously(Cyanokit contains two 2.5 gbottles) over 30 minutes or fasterif the casualtys condition isdeteriorating.

Sodium thiosulphate is a sloweracting agent but may be useful asan adjunct to hydroxycobalamin.It reacts with cyanide to formthiocyanate.

Dose:Administer 12.5 g sodiumthiosulphate (50 ml of 25% solution)over 10-20 minutes through aseparate intravenous line. This maybe repeated at half the initial dose 30minutes later.

Kelocyanor (dicobalt edetate)is nolonger a preferred antidote.

Monitoring in hospital Arterial blood gases (ABGs).

Severe metabolic acidosisrequires correction.

Fluid and electrolyte balance.

Neurological, respiratory andcardiovascular status. Watch forthe development of pulmonaryoedema and aspiration pneumoniain comatose patients. Seizures willrequire treatment with intravenousor rectal benzodiazepines.

Further antidote administration maybe required, particularly if thereis a persisting metabolic acidosis.

Oxygen therapy will be determinedby the response to the antidote.

Close monitoring shouldcontinue for a minimum 24-48hour period following exposureif an antidote has been requiredas delayed effects may occur.

Following skin exposure, aperiod of 6 hours of monitoringis required to ensure there areno delayed effects.

Re-assessment of eye splashesis required within 24 hours, andophthalmologic assessment isrecommended.

Cyanidemanagement planEach site should develop a medicalmanagement plan, including theidentification of the nearest medicalfacility capable of treating a victimof cyanide poisoning and discussionwith an experienced doctor.

ReferencesAgency for Toxic Substancesand Disease Registry (ATSDR), USDepartment of Health and Human

Services, Toxological profiles for andToxFAQs Cyanide: viewed 27 July 2007

Braitberg G & Vanderpyl M, 2000,Treatment of cyanide poisoning inAustralasia. Emergency Medicine12,232-240.

Beasley D. & Glass W, 1998, Cyanidepoisoning: pathophysiology andtreatment recommendations.Occupational Medicine 48(7), 427-431.

Cummings T, 2004, The treatmentof cyanide poisoning. OccupationalMedicine 54, 82-85.

Micromedex Healthcare series -Cyanide.

For further information regarding thehealth surveillance (MineHealth) andcontaminant monitoring (CONTAM)systems managed by Resources Safety,please contact:

Email:contammanager@docep.wa.gov.auPhone: +61 8 9358 8108

Fax: +61 8 9358 8188

www.docep.wa.gov.au/ResourcesSafety

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The information contained in this bulletin is provided in good faith and believed to be reliable and accurate at the time of publication.