Which statement INACCURATELY characterizes the health effects of carbon monoxide exposure?

Which statement INACCURATELY characterizes the health effects of carbon monoxide exposure?

• A. it heightens nervousness and mental agitation
• B. it forms carboxyhemoglobin with blood
• C. it deprives the body of oxygen
• D. it is lethal at concentrations exceeding 5000 ppm

Answer: (A)

Carbon monoxide causes harm mainly by depriving tissues of oxygen. It does this because CO binds to hemoglobin with a much higher affinity than oxygen, forming carboxyhemoglobin and reducing the blood’s ability to carry oxygen. This not only lowers the amount of oxygen delivered but also makes it harder for tissues to release what little oxygen remains, since the dissociation curve shifts in a way that hinders oxygen unloading. Because of this hypoxia, symptoms fall along the lines of oxygen deprivation—headache, dizziness, confusion, weakness, nausea, and shortness of breath, with possible loss of consciousness or death at very high exposures. The statement that CO exposure heightens nervousness and mental agitation isn’t a typical characterisation of its effects; agitation isn’t a hallmark feature of CO poisoning. The other statements fit what CO does: it forms carboxyhemoglobin in the blood, it deprives the body of oxygen, and very high concentrations (in the thousands of ppm) can be rapidly lethal.

Carbon monoxide causes harm mainly by depriving tissues of oxygen. It does this because CO binds to hemoglobin with a much higher affinity than oxygen, forming carboxyhemoglobin and reducing the blood’s ability to carry oxygen. This not only lowers the amount of oxygen delivered but also makes it harder for tissues to release what little oxygen remains, since the dissociation curve shifts in a way that hinders oxygen unloading.

Because of this hypoxia, symptoms fall along the lines of oxygen deprivation—headache, dizziness, confusion, weakness, nausea, and shortness of breath, with possible loss of consciousness or death at very high exposures. The statement that CO exposure heightens nervousness and mental agitation isn’t a typical characterisation of its effects; agitation isn’t a hallmark feature of CO poisoning.

The other statements fit what CO does: it forms carboxyhemoglobin in the blood, it deprives the body of oxygen, and very high concentrations (in the thousands of ppm) can be rapidly lethal.