Comparison of patient state index and end tidal anaesthetic concentration monitoring on recovery profile in desflurane based anaesthesia in neurosurgical population

• Author Details:   
• Sameeksha A J
• Geetha Lakshminarasimhaiah ^*
• Namratha Sudhir
• Roshika Gopalakrishnan
• Swetha Basavaraj
• Pooja Krishnaswamy

---

Background and Objective: A variety of EEG-derived monitors have emerged to track cerebral electrical patterns during general anaesthesia with the goal of improving emergence quality. This study aimed to evaluate recovery characteristics when guiding desflurane based anaesthesia by either the patient state index (PSI) or by measuring end tidal anaesthetic concentration (ETAC) in neurosurgical patients.

Materials and Methods: A total of 108 adult patients (aged 18–65 years) undergoing elective neurosurgery were enrolled in this randomised controlled trial to compare two strategies for anaesthetic depth monitoring: one based on end-tidal anaesthetic concentration (ETAC) and the other on the Patient State Index (PSI). All patients received a standardized general anaesthetic regimen consisting of oxygen, nitrous oxide, and desflurane. In the ETAC group, anaesthetic depth was maintained at a minimum alveolar concentration (MAC) of 0.8–1, whereas in the PSI group, the target was a Patient State Index (PSI) between 25 and 50. Recovery parameters included the emergence time, the ability to respond to verbal commands, and the duration until extubation. Additionally, intraoperative hemodynamic parameters, along with total consumption of desflurane and fentanyl, were documented.

Results: The mean emergence time was 4.94 ± 1.63 minutes in the ETAC group compared to 4.00 ± 1.78 minutes in the PSI group (P = 0.005). The time to respond to verbal commands averaged 5.46 ± 1.80 minutes in the ETAC group versus 4.35 ± 1.66 minutes in the PSI group (P = 0.001). Extubation occurred at 8.07 ± 1.80 minutes in the ETAC group and at 6.65 ± 2.31 minutes in the PSI group (P = 0.001). Desflurane usage was similar between the groups, with the PSI group receiving 18.15 ± 5.88 ml and the ETAC group 18.7 ± 6.21 ml (P = 0.634). Hemodynamic parameters remained stable and comparable across both groups.

Conclusion: Monitoring the depth of anaesthesia with the Patient State Index facilitates a more rapid postoperative recovery compared to ETAC-guided anaesthesia in neurosurgical patients receiving desflurane, without adversely affecting hemodynamic stability.

Keywords: Patient state index, End-tidal anaesthetic concentration, Recovery profile, Desflurane.