You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is In below capnograph the red pa represent:- and explain in detail?
First phase (A-B) represents the initial stage of expiration. Gas occupying anatomic deed space, devoid of Co2 represent this phase. Second phase (B-C)- represent a sharp upstroke when Co2 containing alveolar gas presents at sampling site. Third phase (C-D) - represents alveolar phase Fouh phase (D-E) - inspiration begins and fresh gas is entrained and touches baseline. Phase C-D may take an upward slope. Point D is the highest Co2 value and is called the end-tidal Co2 (ET Co2). ET Co2 is the best reflection of the alveolar Co2 (PA Co2). Normal value of ET Co2 - 35-45 mm of Hg.