Comparison between Dexmedetomidine and Esmolol for Hypotensive Anaesthesia during Functional Endoscopic Sinus Surgery in Children

Abstract
Background: The nasal surgery in pediatric patient's caries a major challenge to both anesthesiologist and surgeon. The surgeon faces small nostrils and narrow nasal passages. The anesthesiologist has to produce condition which facilitate the surgery, decrease the operative time by minimize the intraop-erative bleeding to allow better visualization this can be achieved by controlled hypotensive anesthesia which is the key issue in the success of nasal surgery in pediatric age group. Controlled hypotension is a technique used to limit intraoperative blood loss to provide the best possible field for surgery.
Aim: The aim of this study is to compare between dexme-detomidine and esmolol for controlled hypotensive anaesthesia in children undergoing functional endoscopic sinus surgery.
Methods and Material: This study was carried out on 60 children, 8-12 years, ASA I-II, scheduled for elective functional endoscopic sinus surgery under general anesthesia. Patients were randomized into two equal groups (30 patients in each group): Group D (I): (Precedex®, Meditera, 200μg/2mL) patients received loading dose of dexmedetomidine 1μg/kg diluted in 10ml 0.9% saline infused over 10min before induc-tion of anesthesia, followed by continuous infusion of (0.4 μg/kg/h). Group E (II): (Brevibloc®, Eczacibasi, 100mg/ 10mL) patients received esmolol as a loading dose 1mg/kg diluted in 10ml 0.9% saline was infused over 1min befor induction of anesthesia followed by continuous infusion of (50mg/kg/h).
In all patients, anaesthesia was induced with propofol 2 mg/kg and fentanyl (1μg/kg) and cis-atracurium 0.15mg/kg. The lung was mechanically ventilated for 3 minutes then endotracheal intubation was done with suitable sized tube. The tidal volume and respiratory rates were adjusted to maintain end tidal CO2 between (32-35mmHg). All patients were mechanically ventilated with 100% O2. Anaesthesia was maintained with isofurane 1.2% and oxygen.
Demographic data: Haemodynamics included heart rate, mean arterial blood pressure at base line, 5min. after infusion of loading dose, 5, 15, 30, 45, 60mins after induction of anaesthesia, at end of surgery and 30mins after recovery.
The quality of the surgical field was assessed using a predefined category scale adopted from Fromme et al.
The total blood loss was measured from the suction apparatus.
Duration of surgery: Recovery profile including: Time of extubation, emergence time "eye opening and response to verbal command".
Post-operative analgesia:
Post-operative sedation: Post operative complications: All patients were checked for complications which were recorded and managed as nausea, vomiting, hypotension and bradycardia.
Results: Our results showed that dexmedetomidine and esmolol can induce statistically significant decrease in heart rate and mean arterial blood pressure comparing to the base line after infusion of the loading dose and during the targeted intraoperative period and so good visualization of the surgical field with no statistically significant difference in blood loss or duration of the surgery or post-operative complication however, dexmeditomidine group showed statistically signif-icant prolonged time of first analgesic request and better post-operative sedation.
Conclusions: Our study concluded that, both dexmedeto-miden and esmolol were safe and effective agents in inducing controlled hypotesion in pediatric patients undergoing func-tional endoscopic sinus surgery. Both drugs were effective in optimizing the surgical condition and inducing dry surgical field allowing better visualization. Dexmedetomidine was associated with prolongation of the time of first call for analgesic request and better post-operatve sedation, however esmolol was associated with rapid recovery.