Dexmedetomidine Versus Dexamethasone as Adjuvants to Bupivacaine in Ultrasound-Guided Sphenopalatine Ganglion Block for Functional Endoscopic Sinus Surgery

Background: Postoperative pain after functional endoscopic sinus surgery (FESS) is often significant, and conventional management relies on opioids and NSAIDs, which carry potential side effects. Ultrasound-guided sphenopalatine ganglion block (SPGB) with bupivacaine provides regional analgesia, but its duration may be insufficient. Dexmedetomidine and dexamethasone are adjuvants known to prolong analgesia and reduce analgesic requirements, yet direct comparative evidence for ultrasound-guided SPGB in FESS is limited.

Design: Prospective, randomized, double-blind, controlled clinical trial conducted at the ENT department, Sohag University Hospital. Eligible patients (age 18-60 years, ASA I-II, elective FESS under general anesthesia) who provide written informed consent will be randomized 1:1:1 using a computer-generated sequence, with allocation concealed in sequentially numbered, opaque, sealed envelopes. Patients with allergy to local anesthetics, coagulopathy or anticoagulant use, anatomical nasal deformities obstructing access, or who refuse participation will be excluded.

Interventions: All patients will receive ultrasound-guided bilateral SPGB with a total volume of 10 mL (5 mL per side) after induction of general anesthesia.

• Group A (control): 8 mL bupivacaine 0.5% plus 2 mL normal saline.
• Group B: 8 mL bupivacaine 0.5% plus dexmedetomidine 1 µg/kg diluted with normal saline to 2 mL.
• Group C: 8 mL bupivacaine 0.5% plus dexamethasone 8 mg (2 mL).

Patients, anesthesiologists responsible for intraoperative and postoperative assessment, surgeons, and data analysts will be blinded to group allocation.

Anesthetic technique: General anesthesia will be induced with propofol 2.5 mg/kg and fentanyl 1 µg/kg, and intubation facilitated with atracurium 0.5 mg/kg. Anesthesia will be maintained with isoflurane in oxygen and atracurium boluses, with mechanical ventilation to keep end-tidal CO2 at 35-45 mmHg.

Outcomes: Postoperative pain scores, duration of analgesia, total analgesic consumption, intraoperative hemodynamic measurements, and adverse effects.

Patients will receive ultrasound-guided bilateral sphenopalatine ganglion block with 8 mL of bupivacaine 0.5% plus 2 mL of normal saline, giving a total volume of 10 mL (5 mL per side), after induction of general anesthesia.

Drug: Bupivacaine & normal saline

Patients will receive ultrasound-guided bilateral sphenopalatine ganglion block with 8 mL of bupivacaine 0.5% plus dexmedetomidine 1 µg/kg diluted with normal saline to 2 mL, giving a total volume of 10 mL (5 mL per side), after induction of general anesthesia.

Drug: Dexmedetomidine & Bupivacaine.

Patients will receive ultrasound-guided bilateral sphenopalatine ganglion block with 8 mL of bupivacaine 0.5% plus dexamethasone 8 mg (2 mL), giving a total volume of 10 mL (5 mL per side), after induction of general anesthesia.

Drug: Dexamethasone & Bupivacaine.

2 mL of normal saline 0.9% added to bupivacaine 0.5% (8 mL) in the sphenopalatine ganglion block to maintain a total volume of 10 mL (5 mL per side) and ensure blinding.

Patients will receive ultrasound-guided bilateral sphenopalatine ganglion block with 8 mL of bupivacaine 0.5% plus dexmedetomidine 1 µg/kg diluted with normal saline 0.9% to a volume of 2 mL, giving a total volume of 10 mL (5 mL per side)

Patients will receive ultrasound-guided bilateral sphenopalatine ganglion block with 8 mL of bupivacaine 0.5% plus dexamethasone 8 mg (2 mL), giving a total volume of 10 mL (5 mL per side)

Time frame: At PACU arrival and at 2, 4, 6, 12, and 24 hours postoperatively

Postoperative pain intensity will be assessed using the Visual Analogue Scale (VAS), ranging from 0 (no pain) to 10 (worst imaginable pain). Pain scores will be compared among the three study groups.Unit of measure : score on a scale

Time frame: From the end of surgery until the first rescue analgesic dose, within the first 24 hours postoperatively.

The time from the end of surgery to the first postoperative rescue analgesic request or administration. Unit of measure: minutes.

Time frame: During emergence from general anesthesia and at PACU arrival

Emergence agitation is defined as a Richmond Agitation-Sedation Scale (RASS) score of +1 or higher. The number of participants with emergence agitation will be reported. Unit of measure: number of participants.

Time frame: From baseline assessment before induction of general anesthesia until the end of surgery

Mean arterial pressure (MAP) will be recorded at baseline, after induction of general anesthesia, and every 10 minutes intraoperatively until the end of surgery. Unit of measure: mmHg.

Time frame: From baseline before induction of general anesthesia until the end of surgery.

Heart rate (HR) will be recorded at baseline, after induction of general anesthesia, and every 10 minutes intraoperatively until the end of surgery. Unit of measure: beats per minute.

Time frame: First 24 hours postoperatively

The total number of postoperative rescue analgesic doses administered, regardless of drug type, during the first 24 hours after surgery.Unit of measure: number of doses

Dexmedetomidine Versus Dexamethasone as Adjuvants to Bupivacaine in Ultrasound-Guided Sphenopalatine Ganglion Block in Patients Undergoing Functional Endoscopic Sinus Surgery