Most patients in our study showed various levels of auto-correlation at different times in their oxygen saturation measurements. The researchers believe that this is an issue relative to understanding the meaning of these data. Oxygen saturation is measured to the nearest whole percent. As oxygen saturation approaches 100 percent saturation, the measurement preciseness seems to effect the data behavior. Examination of Figures 2 through 4 leads to only one conclusion, that a single sample per hour is not an adequate representation of the patient's vital signs during throughout the hour.
Current procedure provides only a fraction of the information available from today's monitors.
The electronic data varied in a range from 90 to 100 percent. The nurse also recorded numbers within this range, yet, the correlation coefficient between the value the nurse recorded and the electronically recorded data is 0.2603, that is an r2 of 0.0677. In non-statistical terms the relationship is weak. Whenever there is a human in the observation and recording loop, the danger of human filtration of data exists. Generally, human filtering consists of not seeing extremely low or high values.