Skilled anaesthesia is required in ENT surgery as both the surgeon and the anaesthetist often share the same field.
ENT surgery has a variety of major and minor surgeries including laser and endoscopic surgeries performed under both local and general anaesthesia.
I. Local Anaesthesia in ENT
Local anaesthesia is commonly used for:
- Ear surgeries like tympanoplasty, stapedectomy, auroplasty and ossiculoplasty .
- Nasal surgeries like submucous section, septoplasty, endoscopic sinus surgery (FESS).
- Oral surgeries like tonsillectomy in adults, oral biopsies etc.
Local anaesthesia is given by infiltration of 2% lignocaine with adrenaline 4% lignocaine topically. Adequate sedation is given by drugs 0.5-1mg/kg. Oversedation should be avoided to maintain the pharyngolaryngeal reflex to prevent the aspiration.
II. General anaesthesia in ENT
Major surgeries are done using general anaesthesia using a cuffed endotracheal tube with throat packing.
Common surgeries performed under general anaesthesia:
- Facial nerve decompression
- Endolymphatic sac decompression
- Tympanoplasty in uncooperative patients
- Nasal polypectomy
- Excision of nasopharyngeal angiofibroma
- FESS -Endoscopic Sinus Surgeries
- Palatal surgeries
- Radical neck dissection
- Endoscopies: Bronchoscopy, oesophagoscopy, direct laryngoscopy and Functional Endoscopic Sinus Surgery (FESS).
III. Anaesthesia in specific cases:
1. Ear surgery: Since ear surgeries are under microscopic vision, minimal bleeding may hamper the operative field. This can be done by using a nitroglycerin drip or patch, sevoflurane,etc.
2. Bronchoscopy: In rigid bronchoscopy the surgeon and the anaesthetist share the same field. Hence it is important to avoid hypercarbia and hypoxaemia. Ventilation is done by Saunder jet injector based on venturi effect for the inhalation of anaesthetic drugs.
3. Laser surgery: Lasers used for the surgeries in larynx and oral cavity can damage the endotracheal tube by excessive heat generation and start a fire. Apart from the routine anaesthesia, the anaesthetic precautions are:
- Limited duration of the laser intensity
- Inspired O2 concentration should be low by 21-30%. Nitrous oxide supports combustion and should be avoided.
- The endotracheal tube is wrapped by a thin aluminium foil to prevent damage by the laser beam.
- Saline soaked pledgets should be placed in the airway to reduce the thermal damage to surrounding structures.
4. Head and neck surgeries: Surgeries for malignancies like pharyngectomy, glossectomy, laryngectomy, parotidectomy have to be carried out with great care, with the aim of establishing and securing an airway. Elective tracheostomy may be done for high risk cases. Close monitoring for complications like bleeding, air embolism, arrhythmias should be done.