ANAESTHESIA FOR EAR SURGERY

1. ANAESTHESIA FOR EAR SURGERY COMMON SURGERIES- External ear Removal of simple lesions Foreign bodies in ext.auditory canal Preauricular abnormalities Exostoses

2. MIDDLE EAR AND MASTOID • Adenoidectomy • Tonsillectomy • Otitis media • Mastoidectomy • Tympanoplasty • Myringoplasty

3. INNER EAR • Cochlear transplant surgery • Endolymphatic sac decompression • Labyrinthectomy

4. TECHNIQUE OF ANAESTHESIA GENERAL ANAESTHESIA • A through preoperative asessment advised. • Specific attention paid to hypertension or any cardivascular disease which limits attempts to control BP introp. • No specific premedication required • Anxiolytics such as alprolazam and temazepam for anxious patients. • Beta blocker or clonidine if required can be given iv with intraop monitoring

5. SPECIFIC CONSIDERTIONS.. CHOICE OF AIRWAY.. FACEMASK • Earlier used for short ear surgeries such as myringotomy and tube insertion • Was cumbersome for both anaesthesiologist and surgeon • Improper oxygenation,theatre pollution and inaccurate monitoring of tidal gases are major diasadvantages.

6. LARYNGEAL MASK AIRWAY • Flexible LMA designed for ent surgeries. • Has a flexible shaft wich is more tolerant to head rotation and flexion and extension. • For minor procedures has an advantage over face mask as it nullifies all disadvantages. • Proseal LMA has allowed major surgeries for over 5 hours.

7. ENDOTRACHEAL TUBE • For most long duration surgeries a reinforced or armored tracheal tube needed to prevent kinking with head rotation. • South facing preformed tube can also be used • Provides airway collection from debris,blood and regurgitated gastric contents.

8. NITROUS OXIDE • Nitrous oxide diffuses from blood to airspaces. • Amount depends on concenteration and duration of surgery. • Causes increase in middle ear pressures during surgery • Excessive negative pressures after discontinuation of N2O can cause displacement of graft.

9. Underlay grafts have decreased graft displacement. • Many anaesthesiologists use nitrous oxide<50% CONC in middle ear surgeries

10. POSITION • Rotation and flexion of head is necessary in most ear surgeries • Measures to prevent compression of jugular and carotid considered. • Lateral tilt of ot table improves surgical access. • Arms should be placed in neutral position • Head up by 15 deg reduces venous pressure and improves operative field.

11. FACIAL NERVE MONITORING • Used for middle ear, mastoid and inner ear surgeries to identify the facial nerve. • Audible and visual signals recorded in the monitor. • Partial or complete neuromuscular blockade abolishes this activity • Essential to reverse the nm blockade and asssess the nerve before proceeding dissection near it.

12. ANTIEMETICS • Middle ear and inner procedures have a higher complications rate • Retching and vomiting also increase venous pressure, and icp or disrupt surgical grafts. • Opoids if possible should be avoided. • Antiemetics like ondansetron,droperidol,scopolamine,dexamethasone and prokinetics like metoclopramide may be used.

13. For all long surgeries… • Dvt prophylaxis advocated. • Temperature monitoring done • Urinary catheterisation be considered.

14. LOCAL ANAESTHESIA • Can be undertaken safely in suitable patients with or without sedation • Preopasessment and intraop monitoring same as for general anaesthesia • Simple external,and some middle ear surgeries in LA • Light sedation with midazolam and propofol • Patient understanding and cooperation vital • LA can be in form of infiltrating lidocaine ,topical administration of lidocaine onto tympanic membrane

15. NERVE BLOCK Infiltration of Anterior and posterior meatal wall-Auriculotemporalnerve,Greaterauriculur nerve Aural speculum-Auriculur branch of vagus Topical application of LA-tympanic nerve

16. ANAESTHESIA FOR NASAL SURGERY TYPES OF NASAL SURGERY • Procedures on external aspect of nose • “ within nasal cavity • “within nasal sinuses • “involving the bony structures

17. SURGERIES UNDER GENERAL ANAESTHESIA • Sinus surgeries • Rhinoplasty • Septorhinoplasty • Nasolacrimal duct surgery • Frontal sinus surgeries • Ant skull base surgeries • Cranofacial resections

18. SURGERIES UNDER LOCAL ANAESTHESIA Procedures on anterior septum Septoplasty Turbinectomy Cauterisation Polypectomy Reduction of simple nasal fractures

19. Preoperative evaluation Same for local and general anaesthesia Specific asessment for • Obstructive sleep apnea • Use of nasal cpap • Cardiovascular status • History of Nsaid use • Samter triad-inc incidence of brochospasm

20. NASAL VASOCONSTRICTORS • Reduce bleeding from from nasal mucosa • Can be used in combination with local anaesthetics • Phenylephrine+lidocaine,lidocaine+epinephrine

21. CHOICE OF AIRWAY Adequate throat packing be done to protect lower airway Both flexible LMA and endotracheal tube can be used. Exam by fibreoptic scope revealed superior lower airway protection by a correctly placed LMA than a endotracheal tube. Towards end of surgery throat pack must be removed with careful examination of oral and postnasal space accompnied by suctioning.

22. EXTUBATION Extubation of tube when pt awake or deep Extubation of flexible LMA when patient can open mouth to command. Awake extubation(Adv-better and quicker laryngeal reflexes and hence lesser chances of lower airway contamination) Disadvantage-higher incidence of laryngospasm,bucking,desaturation

23. Deep extubation: Adv- • Improves recovery profile, • lesser chances of laryngospasm Disadvantage- • leaves an unprotected airway • dangerous in pts of OSA

24. POSTOPERATIVE CONSIDERATION Almost all pts have complete or partial airway obstruction. Significant in OSA patients OSA patients can have nasopharangeal airway incorporated into nasal pack Pain is usually mild so oral aceaminophen and a NSAID are adequate. IV canula to be retained till removal of nasal pack

25. ANAESTHESIA FOR THROAT SURGERY INTRAORAL SURGERY • TONSILLECTOMY • ADENOIDECTOMY • PALATAL SURGERY LARYNGEAL PROCEDURES • BENIGN,MALIGNANTAND STENOTIC LESIONS • AIRWAY ENDOSCOPY • LASER SURGERY

26. Preoperative assessment • Identify patients with OSA • Loose teeth • Vunerable dental implants • Bleeding disorders • Anaemia • Active infection • Sickle cell disease status • RTI infections inc risk of bleeding,surgery should be postponed

27. GENERAL ANAESTHESIA • Maintain sufficient of anaesthesia • IV induction with propofol,fentanyl with a short acting muscle relaxant • Inhaled induction in uncooperative children,and needle phobic adults • Inhalational induction can be dangerous in pts with OSA • During procedure both spontaneous and ippv can be used

28. Oral packing must be done adequately • During spontaneous ventilation constant observation of reservoir bag done. • Timing of extubation to reduce incidence of laryngospasm ANALGESIA: • Tonsillectomy more painful in adults ,so adequate intraoperative and postoperative analgesia must be provided • Intraoperativeopoids usually necessary • Role of Aspirin in analgesia controversial

29. STEROIDS • IV dexamethasone .05-.15 mg/kg improves recovery • Decrease postoperative emesis • Increased tolerance to regular diet • Analgesia ANTIBIOTICS Reduce fever ,halitosis Earlier return to normal oral intake No effect on analgesia

30. POSTOPERATIVE NAUSEA AND VOMITING Ondansetron,granisetron,dexamethasone have good antiemetic effect Ondansetron .15mg/kg better than metoclopramide .25 mg/kg Pt should be well hydrated and receive regular non opioid analgesia postoperatively.

31. Post extubationlaryngospasm and stridor • Incidence more after removal of tube than flexible LMA • Incidence-12-25% • Methods of reducing laryngospasm • Topical lidocaine 2-4% application • IV lidocaine 1mg/kg • Administration of propofol close to extubation • IV magnesium also used

32. CHOICE OF AIRWAY Choice of tracheal tube,flexible LMA depend on experience of anaesthesiologist Flexible LMA should be only used by experienced anaesthesiologist

33. TRACHEAL TUBE: Southfacingendotracheal tube Most common way of airway maintainance More resistant to compression from mouth gag Less likely to obstruct during surgery Occupies less space in oropharanynx than flexible LMA During extubation careful laryngoscopy is done with suctioning to ensure no blood clots are present Pt placed in tonsil position Extubation deep or awake

34. FLEXIBLE LMA: Requires cooperation b/w anaesthesiologist and surgeon Care required during placement of surgeon Mechanical obstruction by tonsilar gag in 2-20% ADVANTAGES • Avoidance of muscle relaxant • Superior recovery profile,fewer episodes of bronchospasm,laryngospasm,bleeding,desaturation • Less aspiration of blood • Better protection of lower respiratory tract than endotracheal tube Flexible LMA removed when pts open their eyes to command

35. Anaesthetic considerations for Bleeding tonsil • Incidence of postophaemorrhage increase with age • Primary bleeds occur within 6 hrs of surgery • Bleeding is usually venous or capillary • Signs are tachycardia,hypotension,excessiveswallowing,pallor ,restlessness,airwayobstuction • Help of a senior anaesthesiologistseeked

36. Pts should be given oxygen • Large bore IV access should be established. • Haemoglobin ,haematocrit ,coagulation status assessed. • laryngoscopy can be difficult because of clots.continuousoozing,intraoralswlling. • Post resustication RSI is preferred. • Smaller sized ET tubes should be available • After intubation ryle tube inserted to evacuate swallowed blood • Inhaled induction difficult is lateral position • More chances of laryngospasm • Extubation done when pt fully awake.

37. ANESTHESIA FOR LARYNGEAL SURGERIES Anesthesiologist and the surgeon are working in the same anatomic field P tspresentwith minor vocal cord lesions to elderly patients with glottic carcinoma and stridor The anesthesiologist has to maintain oxygenation, remove carbon dioxide, protect the airway, and keep the patient anesthetized, while the surgeon is operating in the same area. Cooperation and communication between the anesthesiologist and the surgeon are essential for success.

38. VOCALCORD PATHOLOGIES 1.Nodules.    2.    Polyps    3.    Cysts.    4.    Granulomas.    5.    Papillomas.    6.    Malignant

39. Preoperative Assessment Anesthesiologist should have some idea of the size, mobility, and location of the lesion Standard airway assessments to predict the ease of ventilation, visualization of the laryngeal inlet, and tracheal intubation should be performed. Airway pathology and its impact on airway severity and size of lesions at the glottic level are assessed by direct or indirect laryngoscopy. Subglottic and tracheal lesions assessed by chest radiography, computed tomography (CT), and magnetic resonance imaging (MRI).

40. Assessment Implication History of endoscopic procedures -Any previous difficulty is significant, and anesthetic records should be reviewed to assess severity and site of obstruction, vascularity of lesion, and previous anesthetic techniques used Hoarse voice -Nonspecific symptom; patients can be hoarse with only minor lesions on the vocal cord or have significant vocal cord pathology and airway compromise Voice changes- Nonspecific symptom; minor lesions can result in significant voice changes Dysphagia- Significant and suggests supraglottic obstruction; if associated with carcinoma implies upper esophageal extension Altered breathing position- Significant; patients with partially obstructing lesions compensate by changing their body positioning to limit airway obstruction Unable to lie flat Significant- suggests severe airway obstruction, and patients may need to sleep upright

41. Breathing during sleep -Significant; difficulty in breathing at night or waking up at night in a panic suggests severe obstruction Stridor- Significant; indicates critical airway obstruction with >50% reduction in airway diameter and in adults an airway diameter of 4-5 mm Stridor on exertion -Significant; suggests airway obstruction is becoming critical; patients may have no stridor at rest Stridor at rest Significant- critical airway obstruction is present Inspiratorystridor- Significant; suggests extrathoracic airway obstruction Expiratory stridor- Significant; suggests intrathoracic airway obstruction

42. Absence of stridor- Generally reassuring, but in exhausted adults and children there are limited chest movements and insufficient airflow to generate enough turbulent flow for stridor • Fiberoptic awake flexible laryngoscopy - Necessary for All adult patients should have this to visualize the vocal cords,great care must be taken to avoid local anesthetic and fiberscope contact with the vocal cords, precipitating total airway obstruction • Chest x-ray/CT/MRI scans- Can identify severity and depth of glottic, subglottic, tracheal, and intrathoracic lesions

43. ANAESTHETIC CONSIDERATIONS FOR ENDOSCOPY Technique depends on Pt general condition Size mobility and location of lesion Use of laser Surgical requirements

44. An ideal technique: (1)Is simple to use (2)Provide complete control of the airway with no risk of aspiration; (3) Control ventilation with adequate oxygenation and carbon dioxide removal; (4) Provide smooth induction and maintenance of anesthesia; (5) Provide a clear motionless surgical field, free of secretions; (6) Not impose time restrictions on the surgeon; (7) Not be associated with the risk of airway fire or cardiovascular instability; (8) Allow safe emergence with no coughing, bucking, breath holding, or laryngospasm; (9) Produce a pain-free, comfortable, alert patient at the end of the operation.

45. Cuffed tube protects airway but can obscure view Most of them are not laser safe Anaesthetic techniques classified into • Closed system • Open system

46. Closed system: cuffed tracheal tube is employed with protection of the lower airway Open system:cuffed tracheal tube is absent using either spontaneous ventilation and insufflation techniques or muscle paralysis and jet ventilation.

47. Advantages of closed system (1)routine technique for all anesthesiologists, (2) protection of the lower airway, (3) control of the airway, (4) control of ventilation, (5) minimal pollution by volatile agents

48. Disadvantages: (1) surgical access and visibility of the lesion may be limited, (2) high inflation pressure may be required through small tubes, (3) tube-related damage to the vocal cords during intubation, (4) risk of a laser airway fire.

49. Advantages of an open system • laser safety, (2) reduced risk of tube-related trauma, (3) complete laryngeal visualization. The disadvantages are • an unprotected lower airway and (2) specialist knowledge, equipment, and experience are required.

50. Closed System—Intubation Techniques Microlaryngoscopy Tubes • Are long, have a small internal and external diameter • Designed specifically for endoscopy procedures. 4- to 5-mm internal diameter tubes with high-volume, low-pressure cuffs used in nasal or oral versions. • Not suitable for laser surgery