| Abstract: | Instantaneous heart rate was recorded in five patients and analysed for change in rate using the criterion of percentage variation either side of the starting rate with resetting throughout the anaesthetic each time the permitted variation was exceeded. The number of occasions on which change occurred was counted, the patterns of change were analysed and the effect of two sampling methods (six-second sample and six-second average) on these patterns was compared. A large number of patients (131) was investigated using the six-second sampling method and the number of changes and patterns of change were evaluated. It is suggested that the six-second sampling technique, combined with the 10 or 15% variation, may be useful for the evaluation of vigilance, and has implications for the design of monitoring apparatus in the future. |
