SPI-guided vs PRD-guided Analgesia During FESS for Intraoperative Blood Loss

Intraoperative blood loss during FESS constitutes a major problem for a surgeon because it influences quality of surgical field. Each incident of haemorrhage makes the operator stop the procedure in order to bring back the optimal visualization of the intranasal anatomy. In the end it prolongs the time of procedure.

Currently, intraoperative blood loss is estimated based on Boezaart Bleeding Scale (BBS) (0 - no bleeding (cadaveric conditions), 1 - Slight bleeding, no suctioning required, 2 - Slight bleeding, occasional suctioning required, 3 - Slight bleeding, frequent suctioning required; bleeding threatens surgical field a few seconds after suction is removed, 4 - Moderate bleeding, frequent suctioning required, and bleeding threatens surgical field directly after suction is removed, 5 - Severe bleeding, constant suctioning required; bleeding appears faster than can be removed by suction; surgical field severely threatened and surgery usually not possible).

Recently, the Surgical Pleth Index (SPI) and Pupillary Dilatation Reflex (PRD) were added as a surrogate variable showing the nociception-antinociception balance into above mentioned parameters constituting a novel approach in monitoring patients intraoperatively, known as adequacy of anaesthesia (AoA) or tailor-made anaesthesia. PRD value >5% reflects increased sensitivity to painful stimulus as well as delta SPI>10 or any SPI>50, and they constitute the indication for administration of rescue analgesia intraoperatively.

This study aims at evaluating utility of SPI-directed analgesia or PRD-directed analgesia or Boezaart scale-directed analgesia using remifentanil on the intraoperative blood loss, haemodynamic stability and time duration of surgery.

Currently, FESS is most often performed using total intravenous anaesthesia (TIVA) which is by majority of anaesthesiologists believed to reduce the intraoperative blood loss compared to general anaesthesia using volatile anaesthetics, but literature provides conflicting findings in this area.

Inclusion criteria

• written consent to participate in the study
• written consent to undergo functional endoscopic sinus surgery under total intravenous anaesthesia
• ASA (American Society of Anesthesiologists) I-III

Exclusion criteria

• age under 18 years old
• allergy to propofol
• pregnancy
• any anatomical malformation making PRD or SE measurement impossible