: Median effective dose of intranasal dexmedetomidine for satisfactory mask induction in children undergoing examination under anaesthesia for retinoblastoma- an up and down sequential allocation study

Inhalational anaesthetic technique is the usual method to induceanaesthesia in children without intravenous access. A smooth, struggle freeinduction not only provides a pleasant experience for the child and parent butalso avoids behavioral disturbance at emergence and prevents psychologicalstress and combativeness due to forceful mask holding. This is particularlyimportant in children requiring multiple examinations under anaesthesia likethose with retinobalstoma. This study envisages to find the median effectivedose of intranasal dexmedetomidine as a premedication to ensure satisfactorymask acceptance during inhalation induction. After a pre-anaesthetic assessmentand informed parental consent, 40 children aged 1-60 months undergoing EUA forRB will be recruited for this study. After ensuring appropriate NPO, the childwill be administered IN dexmedetomidine in the pre-operative waiting area. Thestarting dose of dexmedetomidine will be 1µg/kg. The score by ModifiedObserver’s Assessment of Agitation/ Sedation scale (MOAA/S) will be noted. Thechild will be taken to the operating room for anaesthesia induction. One parentwill accompany the child. Anaesthesia will be induced using a mask and gradualincremental doses of sevoflurane in oxygen and various parameters including maskacceptance, time to loss of eyelash reflex and hemodynamic parameters will benoted. Successful mask acceptance is defined as a calm, co-operative (with orwithout reassurance) or asleep child during inhalational induction. Anintravenous line is secured and anaesthesia is maintained using any techniqueas deemed appropriate by the attending anaesthesiologist. The details like modeof maintaining the airway (mask, LMA), use of fentanyl, propofol, need forfocal therapy like LASER, cryotherapy or intravitreal injection and duration ofprocedure and anaesthesia are noted. The recovery characteristics like time toreach modified Aldrete score of 9, and any untoward event like coughing,laryngospasm, vomiting, desaturation, Bradycardia at induction , maintenance orrecovery will be noted. The parental satisfaction score with regards to theinduction technique as compared to any previous experience will be recordedprior to discharge of the child from the hospital

The end point of the study is at discharge of the child from thehospital. The dose of IN dexmedetomidine in the following child will depend onthe mask acceptance in this child. A dose increment of 0.2µg/kg will be done ifthe score for mask acceptance is poor and the child is cryful and combative atinduction. A decrement of 0.2µg/kg in dosing will be done for the next child ifthe mask acceptance was effective and successful and smooth.