TOX 8 - Carbon monoxide

Question 1

COHb levels in body

Answer 1

Normal COHb is 1% of the whole Hb concentration (5-10% in smokers)

40% - collapse
60% - death

In carbon monoxide poisoning;

o 15% may produce symptoms

o 40% lead to collapse

o 60% to death

Question 2

Mechanism of action

Answer 2

• Carbon monoxide binds reversibly to the O2 binding site on Hb –> reducing affinity for oxygen.

• There is reduction of oxygen transport and the heart is most affected
• forms carboxyhemoglobin (COHb) –> decrease the oxygen –carrying capacity of the hemoglobin
• and inhibit transport, delivery and utilization of oxygen in the body
• 250 times higher affinity compared to O2
• Shifts the oxygen – dissociation curve to the left

Question 3

Clinical symptoms

Answer 3

Progressive hypoxia:

1. Psychomotor impairment
2. Headache
3. Blurred vision, loss of visual acuity
4. Tachycardia, tachypnea, syncope, coma
5. Deep coma, convulsions, respiratory failure, shock

– Headache, confusion, vertigo

– Nausea, malaise, fatigue

– Tachycardia, tachypnea

– Syncope – COHb concentration in blood >50%

– Coma, respiratory failure -> death

Leads to hypoxia –> symptoms first of all in the heart and CNS

Question 4

Treatment

Answer 4

o Remove exposure source

o Maintain ventilation

o Admin O2

o Hyperbaric O2 treatment

Question 5

Chronic intoxication

Answer 5

Long term consequences – chronic poisoning

o Headache, nausea and vomiting

o Lightheadness

o Confusion and depression

o Memory loss

Question 6

Poisoning route

Answer 6

inhalation of CO

Question 7

CO properties

Answer 7

Colorless and odorless,
non -irritating gas

Question 8

affinity to O2- O2 and CO

Answer 8

CO has 250 times higher affinity compared to O2

Question 9

CO shift o2 dissociation curve

Answer 9

Shifts the oxygen – dissociation curve to the left

Question 10

Syncope – COHb concentration in blood

Answer 10

COHb concentration in blood >50%