Periodic respiration. The capnographic interpretation

Different type of periodic respiration are difficult to distinguish clinically although their identification may influence the diagnosis, prognosis and treatment. Often other forms of abnormal respiration are mistaken for periodic. Four capnograms are shown illustrating (1) true Cheyne-Stokes respiration, (2) irregular "pseudo-periodic" respiration a) after fentanyl, and b) in the presence of a brain tumour and (3) regular respiration interspersed with deep sighs which was diagnosed clinically as Cheyne-Stokes respiration. A plea is made for the routine use of capnography in order to provide a visual record of respiration.