Capnography is a type of graph which monitors partial pressure of carbon di oxide in the respiratory gases used during anaesthesia.
Below is a capnogram which shows you various waves- a,b,c,d,e
a to b is dead space exhalation, b is the start of alveolar exhalation, b to c is the upstroke of exhalation where dead space gas mixes with gases in lungs, c to d indicates exhalation, d is the peak concentration while d to e is inspiration washout.
Shark fin shaped capnograph is seen in bronchospasm, while flat capnogram is seen in anaesthesia tube getting disconnected, mechanical ventilation failure, extubation, and 100% bronchospasm. You can see all types of capnograms capnography.com
Usually capnography is seen over Bispectral monitor present on anesthesia machine you can see it here