Cyanosis cannot occur in severe anaemia because: (A) Anaemic blood has a higher O2 carrying capacity per gram of Hb, (B) It requires a critical concentration of reduced Hb in blood, (C) Patient improves his alveolar oxygen as a compensation for anaemia, (D) There is an increased blood flow through the skin
Answer is B. Cyanosis seen when deoxygenated hb >4 gm. so in severe anemia where HB less than 4 gm we cannot see cyanosis.