Carbon Monoxide Oximetry

Course Objectives Define carbon monoxide and carbon monoxide poisoning. Describe the causes of carbon monoxide poisoning. Identify signs and symptoms of carbon monoxide poisoning. Describe the BLS care and treatment for a patient suffering carbon monoxide poisoning.

Course Objectives- cont’d Describe the steps needed to properly identify carbon monoxide poisoning using a CO Oximeter Describe how to identify false readings of a CO Oximeter Identify the risks of carbon monoxide poisoning to EMS providers and firefighters

Course Objectives- cont’d Describe the danger(s) in treating and releasing (not transporting) a patient with a signficant carbon monoxide exposure

A-EMT Course Objectives (in addition to BLS objectives) Describe when IV therapy and advanced airway procedures may be needed in a patient with carbon monoxide poisoning.

Paramedic Course Objectives (in addition to EMT-B and A-EMT objectives) Describe advanced life support procedures that may be needed in a patient with carbon monoxide poisoning.

Key Vocabulary Carbon monoxide Carboxy-hemoglobin Concentration Duration Half-life Hemoglobin Hydrocarbon Hyperbaric oxygen treatment (HBO)

Key Vocabulary (continued) Hypoxia Imitator Impairments Incomplete combustion Liquefaction Mimic Molecules Parts per million (PPM)

Key Vocabulary (continued) Pathophysiology Physiological Poisoning Red blood cells Suffocation Tissue hypoxia Transcutaneous

Carbon Monoxide Poisonings 5,000 fatalities annually in US 10’s of thousands poisonings annually in US Most common cause of accidental postings deaths for decades

What is Carbon Monoxide? Colorless Odorless Tasteless “Silent killer” “Great Imitator” Measured in parts per million or PPM

Carbon Monoxide: Translating PPM to SpCO PPM or “Parts Per Million” is the atmospheric concentration of the gas. PPM is a common fire ground safety measurement, often misleading as CO forms in pockets. SpCO as measured by a CO Oximeter is a function of PPM CO and total time of exposure to the poison. Age and health may be a factor. Even low PPM levels can lead to high SpCO if exposure is long enough; common in overhaul after a fire. Even at 50 PPM for 60 minutes- requires assessment and possible medical treatment with oxygen.

“PPM CO” x “Exposure time” = SpCO

Causes of Carbon Monoxide Incomplete combustion of wood, or by hydrocarbon products such as: Home heating oils Charcoal Kerosene Coal Gas

Common CO Poisoning Sources Faulty furnaces, heaters Auto exhaust Gas generators Charcoal grills used indoor Tobacco smoke Fires Small gas engines or equipment Gas appliances Gas heaters in enclosed area

An Idaho example……. “A family of eight people nearly died Sunday night, after using a charcoal grill to heat their trailer home. Owyhee County Deputies arrived to the home after a frantic 9-1-1 call from one of the women inside the house. All eight including five children were taken to an area hospital and treated for Carbon Monoxide poising. Investigators say the family is doing fine, but lucky to be alive.” Idaho Press Tribune, 2007

Carbon monoxide pathophysiology overview Carbon monoxide is inhaled and passed from the lungs to the blood binding to hemoglobin. Produces carboxyhemoglobin. Affinity to hemoglobin 250 X greater than oxygen. Reduces oxygen carrying capacity of blood. Alters release of remaining oxygen to cells. Acts as an intracellular toxin. Poisons cells and tissue.

Carbon monoxide pathophysiology overview- cont’d Binds with myoglobin in muscle. Interferes with heart and skeletal muscle. Immediate threat to life. Oxygen starvation. Cardiac arrhythmias. Alters judgment, reasoning.

Carbon monoxide pathophysiology overview- cont’d Long-term health effects Central nervous system damage. Cardiovascular damage.

Where does oxygenation take place? Blue dots represent carbon dioxide, white dots represent oxygen. Oxygen enters through the lungs and is exchanged with carbon dioxide at the alveoli. During CO poisoning, oxygen cannot bind to the hemoglobin (no room at the inn theory)

Another example of oxygenation Oxygen is carried from the lungs by the blood hemoglobin to the tissues; here the beating heart is shown, and normal healthy oxidative metabolism goes on. During Carbon Monoxide poisoning, CO is carried from the lungs by the blood hemoglobin to the tissues, preventing oxygen from being carried, and blocking normal oxidative metabolism. Note how slowly and weakly the heart is beating, since it is starved for oxygen (i.e.. blue in color).

How does CO prevent oxygenation of tissues? Normal oxygenation of the hemoglobin molecule. As it goes from (deoxy)hemoglobin to oxyhemoglobin the color changes from blue, as in venous blood, then to pink, as in arterial blood. Here carbon monoxide (CO) enters the picture, and through its very high affinity for hemoglobin, displaces the oxygen from the hemoglobin. This prevents oxygen being carried to the tissues and organs of the body. Carboxyhemoglobin is reddish in color.

Factors That Affect Severity Amount of carbon (concentration) Time (duration) Activity level (during exposure) Health Age

Who is High Risk? Specific Occupations (fire & EMS) Elderly Children Infants Pregnant mothers Unborn children People with existing health problems

Signs & Symptoms Headache Dizziness Weakness Nausea Vomiting Chest pain Altered LOC Flu-like

Signs & Symptoms (continued) Suspect CO poisoning when: Several symptoms are reported at same time No other cause can be identified More than one person at scene reports similar symptoms

Nervous System Effects Effects may mimic a stroke Brain death Long term neurological effects may result

Cardiovascular System Effects Hypotension Clotting disorders Dysrhythmia’s Symptoms may mimic MI

Detection for EMS responders CO Oximetry: non-invasive method of detecting carbon monoxide in patients CO-oximeter (example: Massimo Rad-57) Detects carboxyhemoglobin levels Detects oxyhemoglobin levels Obtains pulse rate Small, handheld battery operated Finger clamp similar to a pulse ox Pulse oximeters cannot detect CO

Treatments: Scene Safety 1st! Rescuer safety is #1 priority Never enter a hazardous scene without PPE and proper respiratory support Remove the patient from the hazardous environment as quickly as possible- don’t become a victim! Follow local protocols

BLS Treatment Remove patient from environment Apply high-flow oxygen Obtain SAMPLE history Complete an assessment Obtain vital signs Use CO-oximeter if available to confirm CO poisoning suspicion Transport to most appropriate facility

ALS Treatment Evaluate respiratory system IV Re-assess LOC & vital signs Evaluate respiratory system IV EKG monitoring- every patient with suspected CO poisoning should receive EKG monitoring Use CO-oximeter if available Transport to most appropriate facility

Specialized Treatment Hyperbaric oxygen treatment or HBO may be recommended. This is still a somewhat controversial treatment as the true reasons behind patient improvement are not well understood. Hyperbaric facts- Patients undergoing hyperbaric treatment are placed in a chamber where 100% oxygen is circulated. The oxygen is pressurized so that air pressure may be 2-3 times greater than normal. Some theorize this allows the lungs and skin to absorb more concentrated oxygen in a shorter period of time. Hyperbaric oxygen accelerates the clearance of CO from the body, restoring oxygen delivery and preventing toxic effects on the central nervous system and blood vessels. Follow local protocols for guidance

A typical SpCO triage algorithm Measure SpCO 0-3% >3% No further medical evaluation of SpCO needed Loss of consciousness, altered mental status or SpCO >25% Yes No Transport on 100% oxygen for ED evaluation. Consider transport to hospital with hyperbaric chamber SpCO >12 SpCO < ? (determined by local protocol) Transport on 100% oxygen for ED evaluation Symptoms of CO exposure? Course of action determined by local protocol

Pitfalls for responders to be aware of- Responders should be very cautious with “treat and release” on patients with CO exposure due to potentially long half life. Moderate to high readings should ALWAYS be confirmed on more than one finger (2 minimum, 3 is preferred). Patients who are extremely cold or have “club nails” may produce a false reading.

Conclusion Consider CO poisoning when symptoms seem suspicious or vague or if the patient has been in an enclosed environment with identified signs/symptoms. Early recognition and treatment and transport to a hospital are critically important in saving the patient and preventing others from being poisoned as well.