Masimo said in a release that results of a study that compared the Massimo Patient State Index (PSi) versus the Next Generation SedLine PSi version were presented at Euroanaesthesia 2017 in Geneva, Switzerland.
Thirty-six healthy volunteers were sorted by age and assigned randomly to four sessions of anesthesia. Participants were under propofol and sevoflurane anesthesia during Masimo SedLine brain function monitoring.
During one session, the volunteers received propofol in graded steps, while in a second session they received sevoflurane in a similar manner. In the third and fourth sessions, volunteers received two different doses of remifentanil.
The volunteers' Modified Observers Assessment of Alertness and Sedation (MOAAS) was tested at each step in each session. Blood samples to measure the drug concentrations were also taken at each step.
The SedLine monitoring incorporated four electroencephalogram (EEG) leads, four EEG waveforms, a Density Spectral Array (DSA) and PSi. The Next Generation version enhanced the PSi. The original and Next Generation PSi algorithms were referred to as PSi-1 and PSi-2, respectively.
“PSi-2 (Next Generation SedLine PSi) has enhanced signal stability and a better description of the dose-response relationship," the researchers concluded in the release. "PSi-2 has therefore improved capacity as a pharmacodynamic monitor of anesthesia compared to PSi-1.”