European Journal of Cardiovascular Medicine

Functional Endoscopic Sinus Surgery (FESS) is regarded as the better management of acute and chronic pathologies in paranasal sinuses, when conservative treatment has failed. By restoring the drainage and aeration of the sinuses, this surgical intervention perpetuates the mucociliary clearance mechanism while conserving the normal non-obstructing anatomic structures.(1)

Bleeding is often troublesome as it reduces the visibility in the operative field, thereby increasing the risk of injury to the optic nerve, orbits, middle cranial fossa and internal carotid artery.(2) Thus, it is mandatory to keep the surgical field as free of blood as possible, in order to improve the visibility of anatomical landmarks and structures.

The advantages of using controlled hypotensive anaesthetic technique during the FESS are reduction in blood loss, improvement in the surgical field, and reduction of the duration of surgery. The baseline mean arterial pressure (MAP) of the patient can be reduced by 30% or maintained at 70-75 mm Hg, using hypotensive anaesthesia.(3)

Esmolol (ESM) helps in controlling the heart rate (HR), contractility, and atrioventricular conduction, by selective inhibition of β1-adrenoreceptors.ESM was found to produce desired hypotension without tachycardia and to improve surgical condition by reducing operative field bleeding in middle ear surgeries.(4,5)

Dexmedetomidine (DEX) is highly specific and potent α2-adrenergic agonist having analgesic, sedative, antihypertensive, and anaesthetic sparing effects when used via systemic route.(6) Prior administration of Dexmeditomidine is also shown to provide a hypotensive anaesthesia and a better surgical field and finally an abbreviated operative duration in spinal and middle ear surgeries.(7,8)Hence the present study is designed to evaluate the effectiveness of selective β1-antagonist Esmolol versus selective α2-agonist Dexmeditomidine in producing intraoperative controlled hypotension during FESS.

Institutional ethical committee approval was obtained and this prospective, randomized, clinical trial was conducted on 60 patients with written informed consent belonging to ASA I-II of either gender aged between 18-60 years scheduled for Functional Endoscopic Sinus Surgeries (FESS) under General Anaesthesia at our institution.

Patients were divided into two groups of thirty each: Group-D:  patients received 1 μg/Kg loading dosage of Dexmeditomidine within 10 min before intubation followed by 0.4 -0.8 μg/Kg/h infusion during maintenance of anaesthesia. Group-E: Patients received Esmolol with loading dose 1 mg/kg being infused over 10 minutes before intubation followed by 0.3-0.5 mg/kg/h infusion during maintenance of anaesthesia.

Patients selected for the present study were randomly allocated by shuffled sealed envelope method by a senior anaesthesiologist. He/She also prepared the infusion solutions of the study drugs and administered the loading dose and maintenance infusions of the study drugs, while the operating surgeon and observing anaesthesiologist were blinded to the administered study drugs.

All patients were premedicated on the night before surgery with Tablet Ranitidine 150mg, and Tab Alprazolam 0.5mg, given through Oral Route, ASA standard NPO guidelines was followed. Two intravenous cannulas were inserted at different sites on both arms – one for infusion of the study drugs (Dexmeditomidine/Esmolol), and one for administration of Intravenous fluids and other drugs, blood etc on the day of Surgery.

Premedication with Inj. Midazolam 0.02mg/kg IV was given after attaching the standard ASA monitors, 5 leads ECG, Non-Invasive Blood Pressure [NIBP] & Pulse Oximetry [SpO₂]. Before induction of anaesthesia, baseline measurements of HR, mean arterial pressure (MAP), and oxygen saturation by pulse oximetry (SpO₂) and EtCO2 were obtained. Patients were than pre-oxygenated for 3 minutes, and anaesthesia was induced with IV Propofol 1.5-2 mg/kg and IV fentanyl l µg/kg. Inj. Succinyl choline 1-1.5mg/kg IV was given and an appropriate size cuffed oral endotracheal tubes inserted and position of ETT confirmed. All patients were operated on by the same surgical unit team. Anaesthesia was maintained with 50% O₂:N₂O & Isoflurane 0.5-1%. Muscle relaxation was achieved by Inj. Vecuronium 0.05mg/kg IV bolus dose & subsequent doses of 1mg every 20 minutes at regular time intervals.  Patient were ventilated with tidal volume of 8-10ml/kg, inspiratory/expiratory ratio of 1:2 and a respiratory rate to maintain an end-tidal CO₂ level of 30-35mm of Hg

The infusion rates of the study drug were titrated to maintain MAP between 70-75 mm of Hg. If MAP decreased below 60 mmHg, the administered infusion dose was reduced by half, and if no response was obtained within 5 minutes, infusion of the hypotensive agent was discontinued and IV Mephenteramine 6mg was given to correct the hypotension. The dose of Mephenteramine required in each patient was recorded. In case of bradycardia (HR <60 bpm) a 20 μg /kg Atropine IV was administered and its use was recorded.

The parameters measured from onset of drug administration till the end of surgery were:  Heart Rate (HR), Systolic blood pressure (SBP), Diastolic blood pressure (DBP), Mean Arterial Pressure (MAP), Oxygen saturation (SpO₂), End-tidal CO₂.

Infusions of the study drugs were stopped 5 minutes before the anticipated end of surgery and Isoflurane was stopped at the end of surgery. Any residual neuromuscular block was antagonized with Neostigmine 50µg/kg and Glycopyrrolate 10µg/kg. Awakening time, time from administration of reversal of neuromuscular blockade till sustained eye opening (for >5 sec) on command, was recorded and patient was to be extubated.

Extubation time along with time to adequate recovery (Aldrete score ≥9 on a scale of 0–10) was recorded in all patients in both the groups. The sedation score was measured using the Ramsay Sedation Score scale at 15, 30, and 60-minutes interval and after extubation surgeon’s satisfaction of the adequacy of surgical site was scored by the same surgeon on a 4-point surgeon satisfaction scale. 1- Bad, 2- Moderate, 3- Good, 4– Excellent.

Rescue Analgesia: Inj. Paracetamol 15mg/kg intravenously was given; Time of First Rescue analgesia was Noted.  Intravenous fluid supplementation was given with maintenance fluid of 2ml/kg/hour of Ringer Lactate solution, plus replacement fluid of three times the average blood loss as calculated by gravimetric method, every half hour, with Ringer Lactate solution. In the recovery room, adverse effects such as nausea, vomiting, agitation, bradycardia, coughing, shivering, reflex tachycardia and rebound hypertension if any were recorded.

2.1 Statistical analysis

In the study, continuous data was represented in terms of means and standard deviations. And the categorical data was represented in the form of frequencies and proportions. Independent samples t-test was used identify the mean difference between two quantitative variables and the variation in means of continuous data over the observation period was analysed using Repeated Measures of Analysis of Variance. P value of <0.05 was considered as statistically significant. Statistical Software SPSS version 22 (IBM SPSS Statistics, Somers NY, USA) was used to analyse data.

Distribution of study participants on Age and ASA grading

The mean age of the participants in the study was 31.48 years with a standard deviation of around ±8.27 years. The minimum age and maximum age of the study participants were 18 years and 54 years, respectively. Majority of the participants in the study belonged to the ASA Grade 1 in both the groups i.e., around 76.7% in Group D, and about 73.3% in Group E. On analysis, the association between ASA grading and the intervention groups was not Statistically significant.

Table 3.1: Comparison of variation in Systolic Blood Pressure (SBP mm Hg) in both groups

Table 3.2: Comparison of variation in Diastolic Blood Pressure (DBP mm Hg) in both groups

Table 3.3: Comparison of variation in Mean Arterial Pressure (MAP mmHg) in both groups

Table 3.4: Comparison of variation in Heart Rate (HR) BPM in both groups

On comparing the variation in means of SBP (table 3.1), DBP (table 3.2), MAP (table 3.3), HR (table 3.4) in both groups, using repeated measures of ANOVA, it was found that there exists a “Statistically significant” relation With P value. Thus, it is evident that Dexmeditomidine was better in causing controlled hypotension on comparison with Esmolol. Initially during the bolus, i.e., within first 10 minutes, the mean SBP, DBP, MAP and HR was reduced in similar proportions in both the groups. However, during the maintenance, Dexmedetomidine was successful in reducing SBP for next 80 minutes, to a greater extent i.e., around 20% from the baseline comparatively.

Table 3.5: Comparison of Rescue Analgesia, Ramsay sedation score, Surgical Satisfaction Score in both groups

The mean values of Duration for rescue analgesia, Ramsay sedation score (RSS) and Surgical satisfaction score (SSS) in the group D was comparatively higher than that in the group E and with a significant p-value. The Dexmedetomidine group took longer to regain full orientation due to the sedative properties of the drug, though they experienced smoother transitions with fewer instances of postoperative agitation. While the bleeding score was lesser in the group D than group E. Thereby, showing that dexmedetomidine gave a better performance than the esmolol.

The participants of either group did not have any clinically or statistically significant adverse events in the postoperative period

Functional Endoscopic Sinus Surgery (FESS) is a widely performed procedure aimed at treating chronic sinusitis and other nasal pathologies. Controlled or deliberate hypotension is a well-established anaesthetic technique to reduce blood loss and improve visualization during functional endoscopic sinus surgery (FESS).(3,9)The primary challenge for anaesthesiologists is balancing the patient's comorbidities with the physiological derangements (i.e. of induced hypotension, reduced cardiac output). The anaesthetic goals for FESS include creating a bloodless surgical field, ensuring airway protection, patient immobility, smooth emergence, and providing sufficient postoperative analgesia. While complications are rare in healthy young patients, the elderly or those with organ dysfunction are at higher risk, necessitating careful patient assessment by the anaesthesiologist.

Boezaart et al. demonstrated that optimal surgical conditions for FESS are achieved with minimal induced hypotension (MAP ≥ 65 mmHg).(10) Based on this, the present study set the target MAP for controlled hypotension at 70-75 mmHg using non-invasive blood pressure monitoring. An ideal agent for controlled hypotension should have a rapid onset, predictable dose-dependent effects, rapid elimination without toxic metabolites, minimal impact on blood flow to vital organs, and should not affect cerebral autoregulation.(11)

Shams et al. conducted a study comparing dexmedetomidine and esmolol as hypotensive agents in FESS, concluding both are safe and effective, with dexmedetomidine providing additional analgesic, sedative, and anaesthetic-sparing effects.(12) However, their study lacked a bleeding score scale and surgeon satisfaction metrics, which were included in the present study.

Erbesler et al. compared esmolol and dexmedetomidine in middle ear surgery, finding both effective but a prolonged neuromuscular blockade with dexmedetomidine and higher costs of surgery with esmolol.(13) Various studies have explored different dosing regimens for these drugs in hypotension. The study conducted by Bajwa et al. Using similar dose of the drugs as per the current study concluded that Dexmedetomidine and esmolol outperformed nitroglycerin in terms of hemodynamic stability and operational field accessibility during FESS.(14) Dexmedetomidine offered the added gain of minimizing analgesic demands and delivering sedation in the postoperative period.

In the present study both the groups were able to achieve targeted induced hypotension during general anaesthesia. There was no incidence of resistant hypertension requiring other antihypertensive. Also, none of the patient in both the study drug groups developed hypotension requiring slowing or stopping of infusion or administration of vasopressors. The SBP, DBP and MAP values at various time intervals during the administration of drugs and at regular intervals during the next 90 minutes showed that it was possible to achieve the target blood pressure levels (MAP=70-75mmHg) with their use and this could be maintained at the same levels during the procedure by titration of the infusion. This is supported by the findings from the studies by Erbesler ZA et.al(13), Valecha DS et.al(15), Shams T et.al(12), Nazir et.al(16) who demonstrated the effectiveness of dexmedetomidine and esmolol. Thus, our observation that both these drugs are efficient to produce controlled hypotension with dexmedetomidine showing superior control of hypotension and heart rate reduction compared to esmolol correlate with the above studies.

Tang et.al(17) and Gurbet et.al (18) in their study found that administering dexmedetomidine intraoperatively lowers the need for perioperative analgesics. Our study too revealed that dexmedetomidine delivered sustained postoperative pain relief.

Postoperative sedation scores were higher in the dexmedetomidine group, indicating better sedation performance. Also, Surgeon satisfaction scores were high for both groups, with dexmedetomidine achieving slightly higher scores. The bleeding score was significantly lower in the dexmedetomidine group, indicating better performance in minimizing bleeding.

Overall, both dexmedetomidine and esmolol are effective for controlled hypotension in FESS, but dexmedetomidine offers advantages in reducing bleeding, controlling heart rate, and providing better sedation and surgeon satisfaction.

Dexmedetomidine and Esmolol are both effective in achieving controlled hypotension during FESS, each with distinct advantages and disadvantages. However, Dexmedetomidine offers stable hemodynamic control, superior surgical field visibility, better sedation and analgesia.

The choice between these agents should be guided by patient-specific factors, surgical requirements, and anaesthesiologist preferences. Further research with larger sample sizes and diverse patient populations could provide deeper insights into optimizing controlled hypotension strategies in FESS, potentially improving surgical outcomes and patient safety.

1. Kennedy DW. Functional endoscopic sinus surgery. Technique. Arch Otolaryngol Chic Ill 1960. 1985 Oct;111(10):643–9.
2. Al-Mujaini A, Wali U, Al Khabori M. Functional Endoscopic Sinus Surgery: Indications and Complications in the Ophthalmic Field. Oman Med J. 2009 Apr 30;24(2):70–80.
3. Tegegne SS, Gebregzi AH, Arefayne NR. Deliberate hypotension as a mechanism to decrease intraoperative surgical site blood loss in resource limited setting: A systematic review and guideline. Int J Surg Open. 2021 Feb;29:55–65.
4. Pilli G, Güzeldemir ME, Bayhan N. Esmolol for hypotensive anesthesia in middle ear surgery. Acta Anaesthesiol Belg. 1996;47(2):85–91.
5. Degoute CS. Controlled Hypotension: A Guide to Drug Choice. Drugs. 2007;67(7):1053–76.
6. Gertler R, Brown HC, Mitchell DH, Silvius EN. Dexmedetomidine: A Novel Sedative-Analgesic Agent. Bayl Univ Med Cent Proc. 2001 Jan;14(1):13–21.
7. Nasreen F, Bano S, Khan RM, Hasan SA. Dexmedetomidine used to provide hypotensive anesthesia during middle ear surgery. Indian J Otolaryngol Head Neck Surg Off Publ Assoc Otolaryngol India. 2009 Sep;61(3):205–7.
8. Hacer Ulger M, Demirbilek S, Koroglu A, Borazan H, Ersoy MO. Controlled Hypotension with Dexmedetomidine for Middle Ear Surgery. Ann Med Res. 2021 May;11(4):0237–41.
9. Adams AP. TECHNIQUES OF VASCULAR CONTROL FOR DELIBERATE HYPOTENSION DURING ANAESTHESIA. Br J Anaesth. 1975 Jul;47(7):777–92.
10. Boezaart AP, Van Der Merwe J, Coetzee A. Comparison of sodium nitroprusside- and esmolol-induced controlled hypotension for functional endoscopic sinus surgery. Can J Anaesth. 1995 May;42(5):373–6.
11. Barak M, Yoav L, Abu el-Naaj I. Hypotensive anesthesia versus normotensive anesthesia during major maxillofacial surgery: a review of the literature. ScientificWorldJournal. 2015;2015:480728.
12. Shams T, El Bahnasawe NS, Abu-Samra M, El-Masry R. Induced hypotension for functional endoscopic sinus surgery: A comparative study of dexmedetomidine versus esmolol. Saudi J Anaesth. 2013 Apr;7(2):175–80.
13. Erbesler ZA, Bakan N, Karaören GY, Erkmen MA. A Comparison of the Effects of Esmolol and Dexmedetomidine on the Clinical Course and Cost for Controlled Hypotensive Anaesthesia. Turk J Anaesthesiol Reanim. 2013 Oct;41(5):156–61.
14. Bajwa SJS, Kaur J, Kulshrestha A, Haldar R, Sethi R, Singh A. Nitroglycerine, esmolol and dexmedetomidine for induced hypotension during functional endoscopic sinus surgery: A comparative evaluation. J Anaesthesiol Clin Pharmacol. 2016;32(2):192–7.
15. Sidhwani Valecha D, Gandhi M, K K A. COMPARISON OF DEXMEDETOMIDINE AND ESMOLOL FOR INDUCTION OF CONTROLLED HYPOTENSION IN SPINE SURGERIES. J Evol Med Dent Sci. 2016 May 2;5(35):2030–5.
16. Nazir O, Wani MA, Ali N, Sharma T, Khatuja A, Misra R, et al. Use of Dexmedetomidine and Esmolol for Hypotension in Lumbar Spine Surgery. Trauma Mon. 2016 Jul;21(3):e22078.
17. Tang C, Xia Z. Dexmedetomidine in perioperative acute pain management: a non-opioid adjuvant analgesic. J Pain Res. 2017 Aug;Volume 10:1899–904.
18. Gurbet A, Basagan-Mogol E, Turker G, Ugun F, Kaya FN, Ozcan B. Intraoperative infusion of dexmedetomidine reduces perioperative analgesic requirements. Can J Anaesth J Can Anesth. 2006 Jul;53(7):646–52.