Background and Goal of Study: Surgical Pleth Index (SPI), derived by finger plethysmography, was introduced to detect nociceptive stimulation and is dependent on analgesic drug concentration [1, 2]. The use of SPI reduced the number of unwanted intraoperative events and opiod consumption during guidance of total intravenous anaesthesia by remifentanil-propofol . The impact of SPI guidance during a balanced anaesthesia setting using a volatile anaesthetic and intermittend opiod administration has not been studied. Therefore, the present prospective randomized controlled trial aimed to examine the impact of SPI guidance during a sevoflurane-sufentanil regimen.
Materials and Methods: Eighty-two patients of ASA physical status I and II, scheduled for either trauma surgery or gynaecological laparoscopic surgery were randomized into either SSI-guided analgesia group (SPI group) or standard practice group (control group). In both groups anaesthesia was induced with propofol and maintained by sevoflurane to keep bispectral index values between 40-50. SPI group patients received a sufentanil bolus (10μg) whenever SPI value was above 50 for more than 30 seconds, whereas in control group patients sufentanil was administered according to standard clinical practice (MAD > 90 mmHg, HR > 80/min, patient movement). Vital parameters, sufentanil consumption, number of unwanted intraoperative events and recovery times were recorded.
Results and Discussion: Sufentanil consumption did not significantly differ between groups (p=0.18) and was 5,84 ng/kg/min in the SPI group and 6,62 ng/kg/min in the control group. No significant difference in terms of hypotensive events (MAD < 65 mmHg, p=0.25), hypertensive events (MAD > 100 mmHg, p=0.13) and unwanted intraoperative events such as movement, coughing or unwanted spontaneous breathing (p=0.89) was recorded between groups. Recovery times (suture to extubation) were comparable with 6,6 min in the SPI group and 7,3 min in the control group (p=0.55).
Conclusion(s): SPI guided analgesia does not significantly improve haemodynamic stability, prevention of unwanted events or improve recovery times during a balanced anaesthesia regimen using sevoflurane and sufentanil.
 Wennervirta J, Hynynen M, et al. Acta Anaesthesiol Scand 2008; 52:1038-45
 Huiku M, Uutela K, et al. Br J Anaesth 2007; 98(4):447-55
 Chen X, Thee C, et al. Anesthesiology 2010; 112:1175-83