2.3. Surgery and perioperative setting
There was a single specialist surgeon and specialist anaesthetist for both groups and the surgical technique did not differ between the study groups. The surgeon was blinded to the fasting status of the patients.
No sedative premedication was administered, and the patients underwent inhalational induction with sevoflurane. Fentanyl 1mg/kg was used for anaesthesia induction, and the patients were not paralyzed for endotracheal intubation. In addition, the patients received Dexamethasone 0.1 mg/kg, Paracetamol 12.5mg/kg, Clonidine 1mcg/kg and intravenous antibiotics. The fluid deficit was calculated using the Holliday–Segar formula(100ml/kg/day for the first 10kg of weight, 50ml/kg/day for the next 10kg and 20ml/kg/day for the weight over 20kg). Intravenous fluid(Lactated Ringers) was given as a bolus intraoperatively to correct for the calculated fluid deficit.
Anaesthesia was maintained with 1—2 MAC of sevoflurane in air, depending on the required level of anaesthesia.
During the surgery, preemptive analgesia-administration of local anaesthetic was given prior to excision of tonsils. Bupivicaine with epinephrine 0.25% or Ropivacaine 1% was administered to the lesser palatine nerves at the junction of the hard and soft palate. During the operation, the specialist surgeon focused on minimal tissue damage to key areas – anterior and posterior tonsillar pillars, the uvula, the underlying constrictor muscles, the posterior oropharyngeal mucosa, the buccal and labial tissues and the tongue.
The adenoids were removed under direct vision with a nasally introduced zero-degree telescope, using an appropriate sized Barnhill adenoid curette technique, along with or without the suction diathermy at settings of Cutting Blend 30 and Coagulation Spray 30. Complete haemostasis was achieved with temporary nasopharyngeal gauze swabs and/or the use of diathermy with these settings.
To remove the palatine tonsils, the diathermy device generally used the following parameters “cutting blend” setting of 10; “coagulation spray” setting of 7; and bipolar coagulation standard setting of 6. To avoid injury to remaining tonsillar area tissues, the surgeon aimed to perform firm tonsil tissue retraction to allow precise dissection of the palatine tonsils from the underlying mucosal surfaces of the anterior and posterior pillars which carry the neuronal fibres of the lesser palatine nerve and the branches of the glossopharyngeal nerve fibres respectively.
Prophylactic control of bleeding points were performed at the tonsillar branch of the facial artery, the tonsillar branches of the ascending pharyngeal artery, the dorsal branch of the lingual artery and the descending palatine artery.
The surgeon minimised additional soft tissue trauma by taking care to minimise blunt dissection of the underlying constrictor muscles, circumvent the use of catheters for retraction of the soft palate and avoided finger palpation of the adenoid bed. The surgeon utilised telescopic identification through the nose to ensure good adenoidal clearance without causing velopharyngeal incompetence or leaving substantial residual adenoid tissue at the posterior nasal choana. The operated area would then be checked to ensure no significant residual clots or retained swabs, and the surgical count with the scrub nurse would be performed.
At the end of surgery, the child was extubated when spontaneous respiration was regular and adequate. After extubation, the child was transferred to the postanaesthesia care unit(PACU) for continuous monitoring of vital signs and assessment of pain, as well as nausea and vomiting. No patients had postoperative intravenous fluids routinely given, but were encouraged to return to normal oral intake of fluids and food. The patients were transferred to the ward when they were fully awake and their cardiovascular and respiratory status was stable.