Objectives: Intraoperative bleeding during endoscopic sinus surgery for severe rhinosinusitis may significantly compromise the surgical field. Saline heated to 50°C promotes transient vessel vasodilation and mucosal edema without causing nasal mucosal necrosis. The brief thermal exposure may induce superficial protein denaturation and facilitate local hemostasis, thereby improving endoscopic visibility. This study aims to assess the impact of 50°C saline irrigation on the overall intraoperative blood loss and surgical visualization during endoscopic sinus surgery for rhinosinusitis.

Methods: This prospective randomized controlled trial study is going to assign the patients to three groups. In the interventional hot saline group (HSI), intraoperative irrigation will be performed with heated saline at 50°C. In the room-temperature saline group (RTSI), saline at 22°C will be used; in the third one group (Control), no irrigation will be administered. Intraoperative blood loss will be recorded in milliliters and milliliters per minute of operative time, and the surgical field will be evaluated using the Boezaart scale.

HSI is hypothesized to be more effective than RTSI in minimizing intraoperative bleeding during FESS.

Introduction Chronic rhinosinusitis (CRS) affects approximately 5-15% of the European population and significantly reduces quality of life. While pharmacological treatment, including intranasal corticosteroids, nasal irrigation, and antibiotics, may be effective in many cases, some patients will require functional endoscopic sinus surgery (FESS). Compared with traditional surgery, FESS will provide better visualization, reduced tissue trauma, fewer complications, and shorter hospitalization. However, intraoperative bleeding will remain a major challenge, as even minor bleeding may impair endoscopic visibility and increase the risk of complications. Various methods, including controlled hypotension, vasoconstrictors, corticosteroids, and reverse Trendelenburg positioning, will be used to reduce bleeding. Heated saline irrigation may also represent a useful supportive technique.

Aim This prospective study will evaluate the effect of intraoperative hot saline irrigation (HSI) on blood loss and surgical field visibility during FESS compared with room-temperature saline irrigation (RTSI) and no irrigation.

Materials and Methods Adult patients with CRS meeting EPOS 2020 criteria and requiring FESS after unsuccessful conservative treatment will be included in this randomized, patient-blinded study. Patients with fungal disease, immunodeficiency, coagulation disorders, neoplastic or autoimmune disease, or preoperative systemic steroid use will be excluded.

Participants will be randomized into three groups: HSI (0.9% NaCl at 50°C), RTSI (0.9% NaCl at 22°C), and control (no irrigation) using coin-toss allocation. Randomization will be conducted by an independent researcher not involved in surgery or postoperative assessment. Separation of responsibilities and independent surgical scheduling will be applied to reduce the risk of selection bias.

Surgical Procedure Surgical procedures will include middle meatal antrostomy, anterior and posterior ethmoidectomy, Draf I-IIa procedure, and bilateral sphenoidectomy performed without preoperative topical decongestants. A 2.7-mm Hopkins nasal endoscope (0°, 30°, 45°, or 70°; Karl Storz) and a microdebrider will be used during all procedures.

Anesthesia General anesthesia will be administered according to a standardized protocol. Anesthesia induction will be achieved with propofol, analgesia with fentanyl or remifentanil, maintenance with sevoflurane or desflurane, neuromuscular blockade with rocuronium bromide, and reversal with atropine plus neostigmine or sugammadex, depending on individual patient requirements.

Study Procedure Nasal irrigation will be performed using 0.9% NaCl at either 22°C or 50°C at least three times during surgery at 10-minute intervals. The 50°C saline solution will be stored in a laboratory incubator, while the 22°C solution will be maintained at room temperature. Irrigation will be delivered through a metal cannula connected to a syringe and inserted into the middle nasal meatus over approximately 5 seconds.

Following each irrigation, the surgical field will be evaluated using the 6-point Boezaart scale after suctioning the irrigation fluid mixed with blood from the nasopharynx. In the control group, surgical field visibility will be assessed every 10 minutes. Total blood loss will be calculated as the difference between the irrigation volume and the total suctioned fluid volume, and mean blood loss per minute will also be recorded.

The primary outcome measure will be total intraoperative blood loss. Secondary outcomes will include blood loss per minute of operative time and surgical field quality assessed using the Boezaart scale.

Data collection and analysis:

This is a pilot study; hence the statistical analysis will be completed at the end of the study.

Each participant will receive a unique study identification number to ensure anonymity and prevent the collection of directly identifiable personal data. Study data will be recorded in a Microsoft Excel database and will include demographic characteristics, comorbidities, current pharmacological treatment, Lund-Mackay CT score, CRS phenotype with or without nasal polyps, type of surgery (primary or revision), anesthetic infusion details, mean arterial pressure and pulse rate measured at 15-minute intervals, endoscopic surgical field assessment scores recorded every 10 minutes, intraoperative complications, use of a microdebrider, total intraoperative blood loss, duration of surgery, and total volume of saline irrigation used.

Inclusion Criteria:

• Chronic rhinosinusitis diagnosed according to the EPOS 2020 criteria;
• Confirmed failure of conservative treatment, defined as persistence of CRS symptoms for more than 12 weeks despite optimal pharmacological therapy;
• Age over 18 years and ability to provide informed consent;
• Written informed consent to participate in the study;
• Presence of inflammatory changes on sinus computed tomography scans.

Exclusion Criteria:

• Lack of patient consent;
• Disease limited to a single sinus;
• Conditions associated with ciliary dyskinesia (e.g., cystic fibrosis);
• Suspected fungal infection or fungal ball;
• Poor adherence to medical recommendations or noncompliance with treatment;
• Suspected neoplastic disease;
• Suspected or confirmed autoimmune disorders, particularly granulomatosis with polyangiitis;
• - Confirmed or clinically suspected immunodeficiency; Diagnosed coagulation disorders or preoperative hemostasis test results outside laboratory reference ranges; Preoperative systemic glucocorticosteroid therapy.

Individual participant data collected during the study will not be made publicly available.