By: 14 January 2015
New measure provides more data on oxygen levels during sedation

The area under the curve of oxygen desaturation (AUCDesat) may provide a more sophisticated approach to monitoring blood oxygen levels during procedures using sedation, according to a recent study led by Paul Niklewski of the University of Cincinnati and colleagues.

Thirteen Board-certified anesthesiologists reviewed a total of 204 records, including information on a wide range of physiological measures, of procedures performed in sedated patients. After review, each anesthesiologist assigned a risk score for that procedure, based on their perceptions of the patient’s risk of complications related to oversedation.

The risk scores were then analysed in depth to determine their relationship to oxygen saturation levels. The researchers were interested in finding out how anesthesiologists’ perceptions of patient risk were affected not only by the presence or absence of desaturation, but also by the duration, depth and number of desaturation events. They also assessed the value of the AUCDesat, which incorporates all four components into a single number.

Overall, arterial blood oxygen level was ranked as the most important factor in assessing patient risk, with an average score of 4.69 out of 5. Respiratory rate was ranked the second most important factor.

Using the data obtained, the researchers were able to define AUCDesat scores identifying groups of patients at low, medium and high perceived risk of complications during sedation, which could be a useful new tool for monitoring patient risk during procedures. “AUCDesat, given it is a single numerical variable, is an ideal endpoint for assessment of risk of adverse clinical outcomes in sedation studies,” concluded Niklewski and co-authors. Further studies to define the role of oxygen desaturation, including how well AUCDesat corresponds to actual physiological outcomes during procedures, is planned.

Niklewski, P.J., Phero, J.C., Martin, J.F. & Lisco, S.J. (2014) Anesthesia & Analgesia, 119(4), 848–856 doi: 10.1213/ANE.0000000000000371