In CO poisoning not true is ..

(C) (Tissue toxicity plays an important role in clinical co-poisoning) (450 A K Jain 5th; 713 Sembolingam 6th)Tissue toxicity plays no role in clinical CO poisoning* CO shift the curve to left' due to inhibition of synthesis of 2.3 DPG. Affinity of CO' to combine with hemoglobin is 210 times more than that of O2Higher affinity of co for hemoglobin produces large proportion of hemoglobin as carboxy- hemoglobin (COHb) and there fore, hemoglobin is unavailable for O2 carriage* CO is also toxic to the cytochromes in the tissues but the amount of co required to poison the cytochrome is 1000 times the lethal dose. Tissue toxicity thus plays no role in clinical CO poisoning - (Ganong)* A carbon monoxide pressure of only o.6 mmHg can be lethal - (Guyton)Hyperbaric oxygen may be used for treatmentCo is competitively bound to hemoglobin and there fore is easily removable provided the partial pressure of 02 is high enough.A patient severely poisoned with carbon monoxide can be treated by administering pure oxygen under hyperbaric condition because oxygen at high alveolar pressure can displace CO rapidly from its combination with hemoglobin.* Carbon- monoxide poisoning is a - Anemic hypoxia type