1 / 29

CO – “The Silent Killer”

CO – “The Silent Killer”. Carbon Monoxide (CO) vs. Carbon Dioxide (CO 2 ). Incidence of CO poisoning. Leading cause of poisoning mortality. Most common cause of death in combustion related inhalation injury. 1000 to 2000 deaths / year ( USA ) Difficult diagnosis :

blue
Download Presentation

CO – “The Silent Killer”

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CO – “The Silent Killer”

  2. Carbon Monoxide (CO) vs.Carbon Dioxide (CO2)

  3. Incidence of CO poisoning • Leading cause of poisoning mortality. • Most common cause of death in combustion related inhalation injury. • 1000 to 2000 deaths / year ( USA ) • Difficult diagnosis : • incidence of unrecognized cases higher • estimated > 42 000 visits / year

  4. Sources of CO • Motor vehicle exhaust • running engine in closed space • faulty exhaust systems • Propane gas -powered equipment • lift, water heater • Combustion for heating or cooking • camping equipment, heating systems • Smoke inhalation in fires

  5. Pathophysiology

  6. Pathophysiology • Hemoglobin’s affinity for CO is 200 to 250 times its affinity for oxygen • CO binding to hemoglobin causes allosteric modifications increasing its affinity for oxygen • Shift of O2 dissociation curve to the left • Decreased tension at which O2 is released from hemoglobin • Less O2 delivery to the cells

  7. O2 Dissociation Curve

  8. Pathophysiology - Cellular level • 15 % of CO bound to extravascular heme-containing proteins • Cytochrome oxidase • alteration in ATP production • intracellular acidosis • persists after exposure • Cardiac and skeletal myoglobin • occuring at COHb 2 % • alteration in tissue O2 uptake

  9. Pathophysiology - Cardiovascular • Myocardial depression consequence of • hypoxic stress • CO binding to cardiac myoglobin • Arterial hypotension • myocardial depression • NO-related peripheral vasodilatation • LOC with reduction of cerebral perfusion

  10. Pathophysiology - Neurovascular • CO in circulation associated with massive increase in NO in perivascular tissues • NO released from vascular endothelial cells and platelets • Production of oxygen radicals from impaired mitochondrial function • Reaction NO with oxygen radicals to form peroxynitrite ( ONOO- ) • Peroxynitrite binds to perivascular tissue proteins causing injury • Increased capillary permeability in CNS and pulmonary vascular beds

  11. Diagnosis - Symptoms • Most common symptoms : headache 91% dizziness 77% weakness 53% nausea 47% confusion 43% shortness of breath 40%

  12. Cont… visual changes 25% chest pain 9% loss of consciousness 6% abdominal pain 5% muscle cramping 5%

  13. Cont… • The Delayed Neuropsychiatric Syndrome • Subacute manifestation (days to months) • Occurs in spite of normal HbCO levels • symptoms including : cognitive defects, personality changes, parkinsonism, amnesia, incontinence, gait disturbances, etc.

  14. Diagnosis - Signs • Physical exam signs • tachypnea, tachycardia, vestibular signs (Ataxia, motion sickness, Nystagmus, circling, head tilt, fall to one side) common • retinal hemorrhages uncommon but more specific

  15. Cont… • Signs of smoke inhalation such as burn nasal hairs, injured mucous membranes, carbonaceous mucus discharge • “Classic” findings of cherry-red lips, skin, and mucus membranes are very rare. Note : - Young children (breath faster), elderly and household pets are usually effected first.

  16. Diagnosis • High level of clinical suspicion • Serum COHb level • Exhaled breath COHb level • Pulse oximetry cannot distinguish between HbO2 and COHb • Comprehensive neurological and neuropsychological assessment • CT brain to exclude other conditions

  17. Severity of CO intoxication • Inhaled CO concentration • Duration of exposure • Presence of systemic illnesses • cardiac and pulmonary diseases

  18. Clinical evaluation • Maintain a high level of suspicion • History of exposure can be absent • COHb • < 3 % non-smokers or < 10 % in smokers • ABG : metabolic acidosis ( lactate ) • ECG : ischemia, arrythmias

  19. Pulse oximetry in CO poisoning • Unreliable with significant amount of abnormal Hb : MetHb, COHb • Pulse oximetry overestimates true fractional arterial oxygen saturation

  20. Neurologic evaluation • Neurologic examination • Neuroradiologic imaging : CT, MRI

  21. Carbon Monoxide AlarmYour best protection! • Install a carbon monoxide alarm close to sleeping areas. For more protection: • Install one in every bedroom • Install one on every level of your home • Never ignore a carbon monoxide alarm, IT COULD SAVE YOUR LIFE!

  22. EmergencyAlarm Sounds! • Get fresh air right away • Call local fire department • Do not re-enter an affected home until CO is gone • Fire department can determine when it is safe to re-enter a building

  23. Management of CO poisoning • Identify the source to correct the problem • Domestic exposition • verification of heating or cooking appliances • Occupational exposition • CO poisoning : mandatory reporting to public health services • Making the diagnosis can save lives !

  24. Cont… • Oxygen 100 % • ABG • COHb • ECG • CXR • Cardiac enzymes • Cardiac monitoring

  25. Hyperbaric oxygen therapy • Enhanced elimination of COHb • Improved tissue oxygenation • Enhanced dissociation of CO from cytochrome oxidase

  26. Classic indications for HBO • Coma or loss of consciousness • Neurologic abnormalities • Cardiovascular dysfunction • Severe metabolic acidosis • COHb > 40 % • COHb > 15 %

  27. CO poisoning in pregnancy • High incidence of neurologic abnormalities and stillbirth after CO poisoning • Fetal Hb binds CO more avidly than Hb A • CO absorption and elimination slower in fetal circulation • HBO felt to be safe in pregnancy

  28. Prevention of CO poisoning • Public education about CO poisoning • Identification of activities at risk • Training of workers for proper use of propane-powered tools • Appropriate ventilation of confined places • Industrial and domestic use of CO detectors

  29. Problems in CO poisoning • Absence of reliable method to estimate prospectively the severity of CO poisoning • Difficulty in comparing results of studies because no staging in severity of disease

More Related