The aim of this randomized trial is to assess the utility of Pupillary Dilatation Reflex (PRD) for monitoring pain perception intraoperatively and its influence on intraoperative blood loss, quality of surgical field using Boezaart Bleeding Scale (BBS) in patients undergoing functional sinus surgery (FESS) under total intravenous anaesthesia using propofol or volatile anaesthesia using sevoflurane or desflurane
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, Pupillary Dilatation Reflex (PRD) was 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 it constitutes the indication for administration of rescue analgesia intraoperatively. This study aims at evaluating utility of PRD-directed analgesia using remifentanil on the intraoperative blood loss, haemodynamic stability and time duration of surgery in patients undergoing functional sinus surgery (FESS) under total intravenous anaesthesia using propofol or volatile anaesthesia using sevoflurane or desflurane 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 current literature provides conflicting findings in this area if the sort of anaesthetic used influences quality of the surgical field.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
120
a rate of infusion will be increased by 50% every 5 minutes until PRD decreases below 5%
PRD value will me measured before the start of FESS after 5 minutes of remifentanyl infusion, when PRD sensitivity \> 5% , infusion of remifentanyl will be increased by 50% until PRD sensitivity \<5% and FESS will be started ; intraoperatively infusion of remifentanyl will be increased by 50% until PRD sensitivity \<5%
blood loss postoperatively
the investigators will measure the amount of blood loss in the suction bag in millilitres (ml) using a syringe after operation of FESS is completed
Time frame: end of operation,' assessment
heart rate stability intraoperatively
the investigators will measure heart rate during TIVAevery 5 minutes up to the end of the operation
Time frame: intraoperative assessment
PRD-guided pain perception intraoperatively
The investigators will measure PRD value and adjust infusion speed of remifentanyl, in the case of PRD value \>5% the speed of remifentanyl infusion will accelerate by 50%, intraoperatively, every 15 minutes or at any change of BBS, up to the end of the operation
Time frame: intraoperative assessment
condition of surgical field
the surgeon will assess the quality of surgical field using BBS when the operation of FESS
Time frame: intraoperative assessment
total consumption of propofol
The investigators will measure the consumption of propofol intraoperatively
Time frame: end of operation assessment
total consumption of remifentanil
The investigators will measure the consumption of remifentanyl intraoperatively
Time frame: end of operation assessment
concentration of desflurane in end-expiratory gas
The investigators will measure theconcentration of desflurane in end-expiratory gas intraoperatively
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Time frame: intraoperative assessment
concentration of sevoflurane in end-expiratory gas
The investigators will measure the concentration of sevoflurane in end-expiratory gas intraoperatively
Time frame: intraoperative assessment