Comparative Evaluation of the Vasodilatory Effects of Desflurane, Isoflurane, and Sevoflurane Using Perfusion Index During General Anaesthesia

BackgroundVolatile inhalational anaesthetic agents produce changes in peripheral vascular tone and systemic haemodynamics.Perfusion index (PI), derived from the pulse oximetry signal, provides a non-invasive measure of peripheral perfusion and can be used to assess changes in peripheral vascular tone.This study was undertaken to compare the vasodilatory effects of desflurane, isoflurane, and sevoflurane using PI as the primary outcome measure and to evaluate associated haemodynamic changes. MethodsThis prospective comparative study included 120 patients (40 each in desflurane, isoflurane, and sevoflurane groups) aged 18-60 years, American Society of Anesthesiologists (ASA) I-II, undergoing elective surgery under general anaesthesia.Anaesthesia was induced with fentanyl 2 µg/kg and propofol 2 mg/kg, with vecuronium 1 mg/kg for airway management, and maintained with the assigned volatile agent at 1.0 minimum alveolar concentration (MAC) without nitrous oxide or other anaesthetic adjuvants.PI was recorded at baseline and at 1, 5, 15, 20, and 30 minutes after induction.Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were also assessed at the corresponding time points.The primary outcome was the difference in PI among the three anaesthetic groups. ResultsBaseline PI was comparable among the desflurane, isoflurane, and sevoflurane groups (1.055 ± 0.136, 1.118 ± 0.153, and 1.112 ± 0.179, respectively; F = 1.960, p = 0.145).Following induction, PI increased significantly in all three groups, with significant between-group differences at every assessed post-induction time point.At 1 minute, PI was 2.753 ± 0.377, 2.493 ± 0.241, and 2.445 ± 0.264 in the desflurane, isoflurane, and sevoflurane groups, respectively (F = 12.183, p < 0.001).At 15 minutes, PI reached 3.285 ± 0.262, 2.850 ± 0.285, and 2.778 ± 0.270, respectively (F = 40.617,p < 0.001).At 30 minutes, the corresponding values were 3.203 ± 0.411, 3.063 ± 0.273, and 2.815 ± 0.422 (F = 10.951,p < 0.001).Desflurane demonstrated the highest PI values at all post-induction time points, whereas sevoflurane generally showed the lowest values.HR was comparable at baseline (p = 0.086) and at 15 minutes (p = 0.440), but significant between-group differences were observed at 1, 5, 20, and 30 minutes.SBP and DBP remained comparable among the three groups throughout the observation period.MAP also showed no significant between-group differences at any assessed time point, including baseline (F = 0.693, p = 0.502), 1 minute (F = 0.133, p = 0.875), 15 minutes (F = 0.101, p = 0.904), and 30 minutes (F = 0.407, p = 0.666). ConclusionDesflurane, isoflurane, and sevoflurane were associated with increased PI following induction of general anaesthesia, with desflurane showing the highest PI values at most post-induction time points.These differences occurred despite broadly comparable SBP, DBP, and MAP among the three groups.PI may provide additional information about peripheral vascular tone alongside routine systemic haemodynamic monitoring; however, the observed differences in PI should not be interpreted as evidence of improved tissue perfusion or clinical superiority of one volatile anaesthetic over another.