Around 50 people die each year in England and Wales from accidental exposure to high levels of carbon monoxide (CO) and hundreds more have their health compromised by exposure to lower levels of CO.

CO poisoning can occur at any time of year and is not limited to those from lower income groups. Older people, children, pregnant women and their unborn children and those with cardiopulmonary disorders are the groups most vulnerable to the effects of exposure to CO.

To address these issues, the Health Protection Agency has, along with other stakeholders, produced two CO diagnostic algorithms (flowcharts) - one for health professionals running smoking cessation clinics and another for GPs and A&E physicians.

Smoking Cessation: Carbon Monoxide

March 2011
This flowchart has been developed to help healthcare professionals running smoking cessation clinics identify patients who might be exposed CO from sources other than products containing tobacco. The flowchart is for use when readings of CO in exhaled breath remain unusually higher than expected in patients who insist they have complied with the smoking cessation programme. As well as aiding identification of such patients, it provides advice and key telephone numbers for services providing further advice and practical assistance to help protect the patient and others who might be at risk.

Carbon monoxide and smoking cessation flowchart (PDF, 65 KB)

To accompany this flowchart, there is a useful NHS patient information leaflet on CO poisoning [external link].

Diagnosing Carbon Monoxide Poisoning Algorithm 

updated October 2010
This algorithm has been developed to help GPs, emergency physicians and other medical professionals in England diagnose and manage CO poisoning among patients who may be exhibiting symptoms more commonly associated with other ailments.

It complements the joint Chief Medical Officer's and Chief Nursing Officer's letter [external PDF] and the NHS patient information leaflet on CO poisoning [external link], which were circulated to medical professionals by the Department of Health in November 2010.

Diagnosing poisoning: carbon monoxide (PDF, 69 KB)

As well as aiding diagnosis, the algorithm also recommends actions to take once a diagnosis is made. It provides key telephone numbers for services providing further advice and practical assistance to protect their patient and others who might be at risk.

How do I get a copy of these resources?

The algorithm and flowchart are both available as free downloadable PDFs from this page.

Hard copies can be obtained from the Department of Health by emailing dh@prolog.uk.com or telephoning 08701 555 455.

Also available is the 2009 letter sent out to GPs and Emergency Physicians.
Diagnosing carbon monoxide poisoning: letter to GPs and Emergency Physicians (PDF, 20 KB)

Continuing medical education on CO

Doctors can gain Continuing Medical Education (CME) points by successfully completing the electronic CME carbon monoxide module on www.doctors.net.uk

Further information on carbon monoxide can be found on the Chemicals Compendium page for CO.

Supporting institutions

The algorithm was developed in consultation with:

• The National Poisons Information Service http://www.npis.org
• The Royal College of General Practitioners http://www.rcgp.org.uk/
• The College of Emergency Medicine http://www.collemergencymed.ac.uk/CEM/default.asp
• The Department of Heath http://www.dh.gov.uk/en/index.htm.

The dissemination of the algorithm is supported by the Gas Safe Register™. Gas Safe Register™ is the new hallmark for gas safety in Great Britain from April 2009. www.GasSafeRegister.co.uk.

Improving diagnosis, enabling rapid treatment and preventing further exposure, will help save lives and prevent illness associated with exposure to CO.