This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Preoperative assessment and monitoring in anaesthesia, Subject name: Anaesthesia
Capnography basically monitors- 
Select and explain. 
A. Central venous pressure, B. Blood pressure during anesthesia, C. Concentration of exhaled CO2, D. Concentration of inhaled O2
C: Concentration of exhaled CO2
Answer: C: Concentration of exhaled CO2 
Explanation: Capnography monitores end tidal CO2 levels ( CO2 in Exhaled gas ) It is based on the principle of absorption spectrophotometry . Normal levels of EtCO2 is 35-45mmg