Background Controlled induced hypotension guarantees less blood loss and better visibility of the surgical site. to the degree of imply intraoperative arterial pressure compared with preoperative blood pressure. Cognitive functions were evaluated preoperatively 6 h and 30 h postoperatively with standardized assessments: the Stroop Test Trail Making Test (TMT) and Verbal Fluency Test Arry-380 (VFT). A decrease in the test results and increase in the number of mistakes made were considered Arry-380 an impairment of cognitive functions. Results A total of 47 patients (group 1 – moderate hypotension – 15 group 2 – intermediate hypotension – 19 group 3 – severe hypotension – 13) were included in the study. A significant decrease was observed in all the 3 groups after Stroop A test 6h postoperatively but it improved 30h postoperatively without differences between the groups. Neither a significant decrease in the test results nor an increase in the number of mistakes was noted for Stroop B assessments TMT A&B assessments and VFT. Conclusions The degree of controlled intraoperative hypotension during FESS did not influence the results of psychometric assessments. MeSH Keywords: Cognition Hypotension Controlled Sinusitis Speech Disorders Stroop Test Trail Making Test Background Controlled induced hypotension is usually a common process during anaesthesia applied to patients undergoing among others endoscopic sinus interventions. Decreased blood pressure allows reduction of bleeding in the surgical field minimization of blood loss better visibility and therefore it increases the surgeon’s comfort and ease reduces the surgery time and prevents complications emerging from blurred vision caused by protection from the surveillance camera lens with bloodstream [1 2 Research have shown a number of strategies reducing bleeding in the operative field through: reducing the mean arterial pressure (MAP) reducing HR regional anemization with adrenaline preoperative use of steroids (which reduce the inflammatory reaction damage to the blood vessels edema and adrenergic receptors activation) and reversing the Trendelenburg position which reduces blood supply in the surgical field. Significant improvement of surgical conditions has been noted with a MAP of 65 mmHg. Magnesium nitroglycerin ACEI (angiotensin transforming enzyme inhibitors) calcium channel blockers beta-blockers sodium nitroprusside clonidine and large doses of inhalational anaesthetics have all been used to achieve the target MAP. Drug-induced vasodilatation is only beneficial if the cardiac output (CO) is reduced. Therefore prevention of reactive tachycardia is necessary. It can be achieved through the administration Arry-380 of labetalol a short-acting beta-blocker which stabilizes the HR at 60 KSHV ORF62 antibody bpm and simultaneously reduces the MAP. Taking into consideration the CO values as an index of both perfusion and bleeding it is affordable to stabilize it within lower normal range values Arry-380 [2-6]. Additionally remifentanil (RFN) an ultrashort-acting opioid and μ receptor agonist also plays an important part in endoscopic surgery of paranasal sinuses. It enables easy adjustment of the depth of anaesthesia and reduction of the MAP and HR through cardiodepressive action [6 7 Earlier studies also indicated the positive effect of propofol as an anaesthetic in reducing MAP through its effect on precapillary arterioles. However it has relatively little effect on the myocardium. Moreover when compared with the combination of sevoflurane and RFN no significant differences in intraoperative bleeding were observed. Additionally this combination enables continuous monitoring of the volatile anaesthetic concentration as well as easy adjustment of MAP during the process [4 8 Some studies have also shown that the return of Arry-380 cognitive functions to the initial level within the first hour seems to be faster in patients on sevoflurane than in those on propofol [9 10 Even though Arry-380 positive effects of controlled hypotension (including reduced blood loss time of intervention and increased comfort and ease of the doctor) are well known the method is still limited by issues regarding the impact of severe hypotension. Permanent brain damage emboli in cerebral blood circulation hard awakening of the patient and even death – all these complications might occur when hypotension.