Pulse-oximetry Derived Perfusion Index as a Predictor of the Efficacy of Rescue Analgesia After Major Abdominal Surgeries

The use of an easy to apply reliable tool is essential to assess pain in patients in intensive care units. This study aimed primarily to evaluate perfusion index usefulness as an objective indicator of pain.

Data were collected from 40 non-intubated adult patients admitted to the surgical intensive care unit postoperatively. The Masimo pulse co-oximetry perfusion index (PI) probe was attached to the patient. At the time of the first request for analgesia (T1), the Behavioural pain scale non-intubated scoring system (BPS-NI) was recorded with the PI and patients' haemodynamics following which rescue analgesia was given. Thirty minutes thereafter (T2), second measurements for the mentioned parameters were taken.

There was a statistically significant reduction in the BPS-NI score, blood pressure and heart rate after analgesic administration (P-values, <0.001, 0.039 and 0.001, respectively), together with a significant increase in the PI (P-value, 0.004). This means that the PI increases with adequate relief from pain, as indicated by a decrease in BPS-NI score and haemodynamics, but the correlation was not statistically significant between their changes.

There was no statistically significant correlation between the PI and the pain score or other clinical indicators of pain either before or after the administration of analgesic.