The recently proposed European guidelines for the management of smoke inhalation and cyanide poisoning—presented at the 6th Mediterranean Emergency Medicine Congress (MEMC) in Kos, Greece, 2011—contrast greatly with usual practice in the UK, where we tend to focus on the management of carbon monoxide (CO) and do not routinely treat or suspect cyanide poisoning. Indeed, a recent survey conducted at the College of Emergency Medicine (CEM) (Hospital Pharmacy Europe, 2011) annual conference revealed that 84% of UK emergency medicine physicians would not routinely consider treating cyanide poisoning empirically in smoke inhalation victims—a key recommendation of the new algorithms presented at the recent MEMC in Kos.
According to Department for Communities and Local Government statistics there were 33,244 accidental dwelling fires in the year ending 31st March 2011 (Department for Communities and Local Government, 2010). With 42% of deaths in house fires coming as a result of smoke inhalation, it is the single greatest cause of mortality in house fires. This number of incidents and the associated mortality serves as an important reminder of how signifcant the problem of smoke inhalation really is.
In my experience as a State Registered Paramedic and Incident Commander it is probable that this lack of routine consideration starts at the scene of an incident, and that crucial information is often not asked for by responders on scene, and therefore not passed on to receiving physicians at the hospital. Currently in NHS ambulance services there is no provision for the specific treatment of cyanide poisoning with antidotes such as hydroxocobalamin. Despite the fact cyanide is a proven cause of mortality in smoke inhalation victims, (Ferrari et al, 2001) the focus of treatment in the UK is primarily on CO poisoning.
‘This number of incidents and the ‘This number of Incidents and the associated mortality serves as an important reminder of how significant the problem of smoke inhalation really is’’
This lack of consideration at the scene of an incident can however be removed by some simple awareness training and asking the correct questions of the Fire and Rescue service on scene. There are various scenarios that can be supposed which explain the requirement for information-sharing, and the difference it may make in treatment regimes could be hugely significant.
Say, for example, you respond to a fire in a fat in the early hours of a Friday or Saturday night. On arrival you are presented with a casualty by the fire-service breathing-apparatus team, who is obviously suffering the effects of smoke inhalation, and presents with evidence of smoke inhalation (soot around nose or mouth), and with neurological impairment, such as confusion. At this point, a simple question to the responding firefighters can make the difference between treating for just CO poisoning or suspecting and treating both CO and cyanide poisoning.
That question is straightforward, but often overlooked: what was on fire?
This may seem basic, but the answer will often be crucial. For example, in a situation where the casualty has left some food in the oven and fallen asleep, leading to the fat becoming smoke-filled, you would be led to the likely conclusion of CO poisoning; the quantity of material on fire is likely to be small, and unlikely to give off much toxic gas other than smoke particles and carbon monoxide.
On the other hand, in a situation where a cigarette has not been extinguished properly and various items of furniture have burnt as a result, responders should start to think of treating or suspecting both CO and cyanide poisoning.
The presence of cyanide in house fire smoke is well established, as it is given off when a variety of household materials incompletely combust, including plastic, wool, wood, and foam in sofas and mattresses.
While the deadly effects of cyanide in smoke are relatively underrecognized in the UK, this threat is better acknowledged elsewhere. In France and the US, cyanide poisoning in house-fire victims is treated more routinely. One of the challenges is the difficulty of confirming cyanide poisoning in a clinically relevant timescale. Where cyanide poisoning testing is available, it is usually several days before the results are received. This means that it is difficult to confirm the diagnosis at the scene. In contrast, carbon monoxide intoxication can be diagnosed at the scene using a gas analyser which is often the case now in the UK.
However in any patient who has reduced neurological and cognitive function, the suspicion of cyanide poisoning should be raised. In many patients the levels of CO measured are in the lower range in comparison to the symptomology and in these cases the index of suspicion of cyanide poisoning should be even higher. The less severe symptoms of cyanide poisoning can be similar to those experienced when hiking or climbing at high altitudes; as intoxication worsens, symptoms become much more severe.
Symptoms of cyanide poisoning:
As a matter of course all cases of smoke inhalation who are unconscious and/or not breathing should receive full advanced life support and be transported to hospital with a pre-alert to the hospital querying cyanide poisoning from smoke.
The treatment of cyanide poisoning from smoke inhalation in the pre-hospital setting where antidotes are not available is no different to the treatment of CO poisoning. Accident and Emergency departments should carry hydroxocobalamin under guidance issued jointly by the National Poisons Information Service and the College of Emergency Medicine stating that it should be immediately available in all emergency departments (National Poisons Information Service, 2011). Where this is the case, the information given on handover to the receiving physician can make a significant difference to the outcome of hospital treatment.
In the United States, France and a number of other European countries, cyanide antidote is carried on frontline emergency medical service vehicles and routinely given pre-hospital. There is a good argument for antidote to be available on the frontline in the UK with some 5596 casualties from house fires last year according to Department for Communities and Local Government (DCLG) figures (Department for Communities and Local Government, 2010). However additional training burden, large numbers of vehicles, and the current economic climate may make this unlikely.
Personally I believe that ambulance services usually target their responses to incidents appropriately, so specialist resources, such as critical care response cars, emergency care practitioners, team leader vehicles, helicopters and hazardous area response teams could carry a cyanide antidote. One of these resources is likely to be deployed to a serious incident. It is likely that this antidote would be hydroxocobalamin, as it is well tolerated and suitable for empiric use; most other conventional cyanide antidotes can make the patient worse rather than better if they have not actually been exposed to cyanide (Cummings, 2004).
The London Helicopter Emergency Medical Service (HEMS) has carried hydroxocobalamin for some time, and it has been seen to be effective on a number of occasions, including in patients who are rescued from fires in cardiac arrest.
Paramedics and ambulance staff are in a good position to inform receiving emergency departments of the likelihood of cyanide poisoning from smoke inhalation, however the onus is then on those departments to ensure that the information is acted upon. It is a good time for all those involved in pre-hospital and in-hospital emergency medicine to ensure that they raise their level of awareness with regards to cyanide poisoning in smoke inhalation, as this could significantly improve outcomes amongst house fire victims.