Peripheral blood perfusion during desflurane anaesthesia

Abstract Peripheral perfusion may be compromised during anaesthesia and surgery, however its direct assessment is difficult, and sometimes may lead to false conclusions. Recently, a new generation of pulse oximeters has been introduced, which allows for the differentiation between pulsatile and non-pulsatile flow. The difference is expressed as the perfusion index (PI). ASA I and II class women, scheduled for elective gynaecologic surgery, received fentanyl/ desflurane anaesthesia were studied. PI was noted before anaesthesia, after fentanyl injection, after endotracheal intubation, at the beginning of surgery, during the procedure at 10 minute intervals, at the end of procedure, after eye opening, after extubation, and before discharge to the ward. The depth of anaesthesia was assessed by spectral entropy and expressed as the A-line Autoregressive Index (AAI); the latter was compared to PI. Forty-five patients aged 37 +/- 13.8 years were enrolled in the study. PI increased after induction of anaesthesia and remained increased during surgery. There was a significant negative correlation between PI and AAI (r = -0.908; p = 0.00000), and between AAI and end-tidal desflurane concentration ((r = -0.788; p = 0.0008). PI correlated positively with end-tidal desflurane concentration (r = +0.757; p = 0.002). The new generation of pulse oximeters allows not only the more accurate assessment of haemoglobin saturation, but also the detection of pathologic forms of haemoglobin and the assessment of peripheral blood flow. Peripheral perfusion is increased during desflurane anaesthesia, and is also closely related to the depth of anaesthesia.