Carbon Monoxide Poisoning

Carbon monoxide (CO) is the commonest cause of death by poisoning in the UK. It is a colourless, odourless gas which forms a part of the gas produced by burning. This can include smoke from fires, car exhaust, or exhaust gas from central heating.

Severe Carbon Monoxide and Smoke Poisoning

Causes	It is well known that CO causes illness by binding to the haemoglobin (in red blood cells) blocking the transport of oxygen around the blood stream. However, it also binds to myoglobin in muscles, which makes the muscles painful and easily fatigued. It also binds to chemicals deep inside all living cells in the body, making it difficult to use oxygen even if it reaches the tissues.
Sources	Fires, Barbecues, paint stripper, Exhaust fumes, faulty boilers, any fuel-burning appliance
Symptoms	Altered consciousness, balance and coordination problems, memory problems, headache, nausea and vomiting, vertigo
HBO in the case of smoke inhalation or carbon monoxide poisoning	Breathing oxygen under pressure washes the gas out of the bloodstream and tissue. Oxygen supply to the tissue is maximised as soon as Hyperbaric oxygen therapy begins. HBO takes effect much more quickly than breathing 100% oxygen under normobaric conditions.
Pre hospital treatment	ABCs, High flow oxygen, Gain I.V. access, I.V. fluids if safe
Referral Criteria for Hyperbaric Oxygen Therapy	Loss of consciousness at any time? Patient has neurological abnormalities? Patient has cardiovascular symptoms? (e.g. Chest pain) Pregnant and COHb level >20% (or probably was at peak)? COHb level >25% (or probably was at peak)? Ingestion of drugs/alcohol? If one or more question is answered with 'Yes' Hyperbaric Oxygen Treatment may be indicated.
Duration of treatment	Standard treatment involves 3 sessions of Hyperbaric Oxygen Therapy within 36 hrs after admission to our Hyperbaric facility. Individual sessions last approximately 2 hrs with patient breathing oxygen for 60 minutes at 2.82 atmospheres.
Aim of treatment	Prevention of permanent damage to brain and heart tissues, reduction of possible long-term effects and the risk of concomitant illnesses.

Poisoning can be acute (less than 24 hours) or chronic (more than 24 hours). The symptoms of poisoning can include loss of consciousness, which is the most serious factor for those who survive the injury. But it is also possible to have other symptoms, including headache, confusion and memory loss, or loss of balance.

Normally, patients with CO poisoning are taken to an Accident & Emergency department, where they are assessed and given oxygen by face-mask. If the problems are severe, patients may be sent to a suitable Hyperbaric Medicine department for intensive treatment.

Patients suffering from severe Carbon Monoxide poisoning should only be treated by Hyperbaric Facilities offering the full range of NHS back-up services.

London Hyperbaric Medicine is currently the only facility within London approved to treat all categories of Emergency Referrals for Carbon Monoxide Poisoning.

The evidence suggests that Hyperbaric Oxygen reduces the risk of later illnesses, which can develop after the first illness is over. Recent research has appeared to show that oxygen by face-mask is just as effective as Hyperbaric Oxygen. However, other research due for publication this year suggests that Hyperbaric Oxygen is better than the oxygen treatment normally given in hospital. This applies only to patients who are severely affected.

The Department of Health has included the treatment of CO poisoning in its definition of Hyperbaric Oxygen services, which was published in the autumn of 2002.

London Hyperbaric Medicine treats between 40 to 60 patients per year suffering from severe carbon monoxide poisoning. Patients are referred to us for treatment by A & E departments from all over the Southeast of England.

Hospital A&E Physicians calling the Poisons Unit at Guy's Hospital for advice on carbon monoxide poisoning will normally be referred to LHM as London's only NHS based facility qualified to treat such patients.