Management

The management of carbon monoxide poisoning includes:

• seek expert advice
• remove patient from source of CO
• 100% oxygen from tight fitting mask
• monitor carboxyhaemoglobin levels and blood gases:
  • 20% carboxyhaemoglobin causes headache
  • 40% causes confusion, lethargy, collapse
  • 60% often fatal
• correct cerebral oedema with mannitol and dexamethasone
• correct acid base disturbance
• provide general supportive measures
• indications for hyperbaric oxygen therapy (HBOT) (1)
  • there is debate about the added value provided by HBOT. While this is advocated by some clinical experts, systematic reviews have not provided conclusive evidence of benefit. Advice on management of patients with serious CO poisoning, especially those with the following features, can be obtained from National Poisons Information Service:
    • the patient has lost consciousness at any stage;
    • the patient has neurological signs other than headache;
    • myocardial ischaemia/arrhythmia has been diagnosed by ECG; and/or
    • the patient is pregnant
  • HBOT should be used for the urgent treatment of CO poisoning (within 24 hours)
    • HBOT is also thought to be of use in cases of extensive exposure to CO and if nerve damage is suspected. Expired air CO and blood COHb are poor guides to prognosis and the need for hyperbaric oxygen therapy. Its use should be on a case-by-case basis
      
      

Hyperbaric oxygen reduces the breakdown time of carboxyhaemoglobin to 30 minutes at an oxygen pressure of 3 atmospheres. There is evidence that, in patients with acute carbon monoxide poisoning, 3 hyperbaric oxygen treatments within 24 hours of exposure reduced cognitive sequelae at 6 weeks, 6 months, and 1 year (3).

People to consult (1):

For measurements in the house:

• for gas: Local CORGI (Council for Registered Gas Installers) engineer - call 0800 915 0485 (N.B. CORGI is the Health and Safety Executive appointed provider of the gas installer registration scheme until April 2009. After that, contact the HSE Gas Safety Line - see below)
• Health and Safety Executive Gas Safety Line - call 0800 300 363
• for oil: Local OFTEC (Oil Firing Technical Association) engineer - call 0845 658 5080
• for solid fuel: Local HETAS (Heating Equipment Testing and Approval Scheme) engineer - call 0845 634 5626
• local Health Protection Unit

Advice on the management of poisoning:

• refer to the local National Poisons Information Service Centre

Reference:

• 1. PL/CMO/2008/8, PL/CNO/2008/8: Recognising Carbon Monoxide Poisoning – 'Think CO'
• 2. PL/CMO/2002/2,PL/CNO/2002,2.
• 3. Weaver LK et al (2002). Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med 347: 1057-67.
• 4. Carbon monoxide: the forgotten killer. Tibbles, P.M., Perrotta, P.L., (1994). Treatment of carbon monoxide poisoning: a critical review of human outcome studies comparing normobaric oxygen with hyperbaric oxygen. Annals of Emergency Medicine, 24, 269-276.