What is the physiological dead space when aerial PCO2 (PaCO2) is 48mmHg, expired PCO2 (PECO2) is 25mmHg and tidal volume of 500ml?: (A) 260ml, (B) 240ml, (C) 220ml, (D) 200ml
Answer is A. Bohr's equation PCO2 x VT = PCO2 x (VT - PDS)25 x 500 = 48 (500 - PDS)12500/48=500 - PDS260 =500-PDSPDS = 240ml