Variability of the respiratory phase, respiratory pause, and numbers and durations of respirations during periodic breathing.

The analysis of cycles of periodic breathing (Cheyne-Stokes rhythms) in 35 patients showed wide variability of mean values of respiratory phases. The respiratory pauses are usually shorter and the scatter of the mean values is smaller. Only in four cases were respiratory pauses longer than respiratory phases. The duration of the respiratory phase becomes extended through the increase of number of single respirations. The latter also shows a very small scatter. The respiratory rate in 32 out of 35 patients was higher than normal and is to be considered as tachypnoea.