ANAESTHESIA FOR EAR SURGERYCOMMON SURGERIES-External ear•Removal of simple lesions•Foreign bodies in ext.auditory canal•Preauricular abnormalities•Exostoses
MIDDLE EAR AND MASTOID• Adenoidectomy• Tonsillectomy• Otitis media• Mastoidectomy• Tympanoplasty• Myringoplasty
INNER EAR• Cochlear transplant surgery
• Endolymphatic sac decompression
• Labyrinthectomy
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
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.
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.
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.
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.
• Underlay grafts have decreased graft displacement.
• Many anaesthesiologists use nitrous oxide<50% CONC in middle ear surgeries
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.
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.
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.
• For all long surgeries…• Dvt prophylaxis advocated.• Temperature monitoring done• Urinary catheterisation be considered.
LOCAL ANAESTHESIA
• Can be undertaken safely in suitable patients with or without sedation
• Preop asessment 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
NERVE BLOCKInfiltration ofAnterior and posterior meatal wall-Auriculotemporal
nerve,Greater auriculur nerve
Aural speculum-Auriculur branch of vagus
Topical application of LA-tympanic nerve
ANAESTHESIA FOR NASAL SURGERY
TYPES OF NASAL SURGERY• Procedures on external aspect of nose• “ within nasal cavity• “within nasal sinuses• “involving the bony structures
SURGERIES UNDER GENERAL ANAESTHESIA• Sinus surgeries• Rhinoplasty• Septorhinoplasty• Nasolacrimal duct surgery• Frontal sinus surgeries• Ant skull base surgeries• Cranofacial resections
SURGERIES UNDER LOCAL ANAESTHESIAProcedures on anterior septumSeptoplastyTurbinectomyCauterisationPolypectomyReduction of simple nasal fractures
Preoperative evaluation
Same for local and general anaesthesiaSpecific asessment for • Obstructive sleep apnea• Use of nasal cpap• Cardiovascular status• History of Nsaid use• Samter triad-inc incidence of brochospasm
NASAL VASOCONSTRICTORS• Reduce bleeding from from nasal mucosa• Can be used in combination with local
anaesthetics• Phenylephrine+lidocaine,lidocaine+epinephrin
e
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.
EXTUBATIONExtubation of tube when pt awake or deepExtubation 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
Deep extubation:Adv-• Improves recovery profile,• lesser chances of laryngospasmDisadvantage-• leaves an unprotected airway• dangerous in pts of OSA
POSTOPERATIVE CONSIDERATION
Almost all pts have complete or partial airway obstruction.
Significant in OSA patientsOSA patients can have nasopharangeal airway
incorporated into nasal packPain is usually mild so oral aceaminophen and a
NSAID are adequate.IV canula to be retained till removal of nasal pack
ANAESTHESIA FOR THROAT SURGERY
INTRAORAL SURGERY• TONSILLECTOMY• ADENOIDECTOMY• PALATAL SURGERYLARYNGEAL PROCEDURES• BENIGN,MALIGNANTAND STENOTIC LESIONS• AIRWAY ENDOSCOPY• LASER SURGERY
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
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
• Oral packing must be done adequately• During spontaneous ventilation constant
observation of reservoir bag done.• Timing of extubation to reduce incidence of
laryngospasmANALGESIA:• Tonsillectomy more painful in adults ,so
adequate intraoperative and postoperative analgesia must be provided
• Intraoperative opoids usually necessary• Role of Aspirin in analgesia controversial
STEROIDS• IV dexamethasone .05-.15 mg/kg improves
recovery• Decrease postoperative emesis• Increased tolerance to regular diet• AnalgesiaANTIBIOTICSReduce fever ,halitosisEarlier return to normal oral intakeNo effect on analgesia
POSTOPERATIVE NAUSEA AND VOMITINGOndansetron,granisetron,dexamethasone have
good antiemetic effectOndansetron .15mg/kg better than
metoclopramide .25 mg/kgPt should be well hydrated and receive regular
non opioid analgesia postoperatively.
Post extubation laryngospasm 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
CHOICE OF AIRWAYChoice of tracheal tube,flexible LMA depend on
experience of anaesthesiologistFlexible LMA should be only used by
experienced anaesthesiologist
TRACHEAL TUBE:Southfacing endotracheal tube Most common way of airway maintainanceMore resistant to compression from mouth gagLess likely to obstruct during surgeryOccupies less space in oropharanynx than flexible
LMADuring extubation careful laryngoscopy is done with
suctioning to ensure no blood clots are presentPt placed in tonsil positionExtubation deep or awake
FLEXIBLE LMA:Requires cooperation b/w anaesthesiologist and surgeonCare required during placement of surgeonMechanical 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
Anaesthetic considerations for Bleeding tonsil• Incidence of postop haemorrhage increase
with age• Primary bleeds occur within 6 hrs of surgery• Bleeding is usually venous or capillary• Signs are tachycardia,hypotension,excessive
swallowing,pallor ,restlessness,airway obstuction
• Help of a senior anaesthesiologist seeked
• Pts should be given oxygen• Large bore IV access should be established.• Haemoglobin ,haematocrit ,coagulation status assessed.• laryngoscopy can be difficult because of
clots.continuous oozing,intraoral swlling.• 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.
ANESTHESIA FOR LARYNGEAL SURGERIES
Anesthesiologist and the surgeon are working in the same anatomic field
P ts presentwith 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.
VOCALCORD PATHOLOGIES 1.Nodules. 2. Polyps 3. Cysts. 4. Granulomas. 5. Papillomas. 6. Malignant
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).
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
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 Inspiratory stridor- Significant; suggests extrathoracic airway
obstruction Expiratory stridor- Significant; suggests intrathoracic airway
obstruction
• 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
ANAESTHETIC CONSIDERATIONS FOR ENDOSCOPY
Technique depends on Pt general conditionSize mobility and location of lesionUse of laserSurgical requirements
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.
Cuffed tube protects airway but can obscure view
Most of them are not laser safeAnaesthetic techniques classified into 1. Closed system2. Open system
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.
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
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.
Advantages of an open system (1) laser safety, (2) reduced risk of tube-related trauma, (3) complete laryngeal visualization. The disadvantages are (2) an unprotected lower airway and (2) specialist knowledge, equipment, and
experience are required.
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
LASER TUBES:• Lasers used for the resection of papillomas,
vascular lesions of the vocal cord, granulomas, and laryngeal carcinoma.
• Carbon dioxide lasers are the most commonly used in airway surgery
• Laser-proof tube is the all-metal Norton tube, which has no cuff.
• Most laser tubes have laser-resistant properties around the shaft
• Cuff is the least protected part of the tube
Open Systems—Nonintubation TechniquesSpontaneous Ventilation and Insufflation
Technique:Useful in the removal of foreign bodiesEvaluation of airway dynamics (tracheomalaciaRemoval of noncompromised glottic and
subglottic lesions. Requires a spontaneously breathing patient and
provides a clear view of an unobstructed glottis
TECHNIQUE IN OPEN SYSTEM
Inhaled induction is begun with sevoflurane in 100% oxygen
At suitable depth laryngoscopy performed with topical lignocaine administration above and below the vocal cords
One hundred percent oxygen is administered by facemask with spontaneous ventilation
Anesthesia is continued with inhalation (insufflation) or an intravenous route (propofol infusion).
At a suitable depth the surgeon undertakes laryngoscopy or bronchoscopy
Routes of insufflation: (1) A small catheter introduced into the
nasopharynx and placed immediately above the laryngeal opening
(2) A tracheal tube cut short and placed through the nasopharynx emerging just beyond the soft palate
(3) A nasopharyngeal airway(4) The side-arm or channel of a laryngoscope or
bronchoscope.
Limitations of spontaneous ventilation or insufflation techniques:
1. Lack of control over ventilation and the potential for airway soiling.
2. Operating room pollution secondary to insufflation of volatile agents
3. May be unsuitable for large, soft, floppy lesions, particularly in the supraglottis or glottis, which may obstruct the airway after the onset of general anesthesia with spontaneous ventilation.
JET VENTILATION TECHNIQUESSUPRAGLOTTIC JET VENTILATION
SUBGLOTTIC JET VENTILATION
TRANSTRACHEAL JET VENTILATION
SUPRAGLOTTIC JET VENTILATION A technique in which the jet of gas emerges in
the supraglottis by attachment of a jetting needle to the rigid surgical suspension laryngoscope.
High-frequency or low-frequency ventilation can be used.
Allow a clear, unobstructed view for the surgeon with no risk of a laser airway fire
Use of LMA provides a smooth recovery from anaesthesia
LIMITATIONS:(1) Misalignment of the suspension laryngoscope to the
glottic inlet, which results in poor ventilation (2) Risk of gastric distention with entrained air(3) Blood, smoke, and debris are blown into the distal
trachea (4) Considerable vibration and movement of the vocal
cords occurs, which may require ventilation to be stopped while operating
(5) Inability to monitor end-tidal carbon dioxide concentration; and
(6) Risk of barotrauma with pneumomediastinum, pneumothorax, and subcutaneous emphysema.
Subglottic Jet VentilationAllows delivery of a jet of gas directly into the
trachea by the placement of a small catheter through the glottis and into the trachea
ADVANTAGES-More efficient than supraglottic jet ventilation 1. Reduced driving pressures2. Minimal vocal cord movements3. A good surgical field4. No time constraints for the surgeon in the
placement of the rigid laryngoscope
Disadvantages: 1. Potential for a laser-induced airway fire2. Presence of a potential fuel source within
the airway, and a greater risk of barotrauma than in supraglottic jet techniques.
TRANSTRACHEAL JET TECHNIQUESUnder local anaesthesia for significant airway pathologyUnder GA for elective laryngeal surgeryLimitations:• carry the greatest risks of barotrauma. • blockage• kinking• infection• bleeding • failure to site the catheter
Inhaled Foreign BodiesForeign body aspiration is the most common
indication for bronchoscopy in children 1 to 4 years old.
foreign bodies can lodge in the larynx, trachea, main bronchi, or smaller airways
effects depend on the duration, degree, and sitepresent with acute dyspnea, stridor, coughing,
and cyanosis.
ANAESTHETIC CONSIDERATIONS:
Spontaneous ventilation preferred to reduce the chances of the foreign body being pushed distally into the airway
And intermittent positive-pressure ventilation may be needed
Sedative premedication should be avoided because it may precipitate total airway occlusion.
Induction is usually by an inhaled technique with sevoflurane or halothane in oxygen
At a deep plane of anesthesia, laryngoscopy is performed, and topical local anesthetic (lidocaine) is administered
Intravenous anticholinergic agents (atropine, 20 µg/kg, or glycopyrrolate, 10 µg/kg) dec.secretions and reflex bradycardia associated with airway instrumentation.
Correct depth of anaesthesia maintained in the procedure by IV propofol
Some bronchoscopes allow the attachment of a T-piece to a side arm on the bronchoscope
Oxygen and volatile agent can pass directly into the distal trachea through them
In some bronchoscopes insufflation techniques are required for ventilation
IV dexamethasone .1mg/kg to reduce airway edema postoperatively.
Humidified oxygen and antibiotics also needed postoperatively
In some pts hdu care may be required for intensive monitoring
HEAD AND NECK SURGERYLaryngectomyPharyngolaryngectomy Radical neck dissectionResection of large thyroid lesions
GENERAL CONSIDERATIONS
More than 80% of laryngeal and oropharyngeal cancers are found in men 40 to 75 years
Greater than 97% of patients are smokers with a high alcohol intake.
Patients may have had Previous radiotherapy and surgery resulting in altered anatomy, tissue edema, induration, and “stiff” tissues
PREOPERATIVE EVALUATIONassessment of alcohol intakeuse of tobacconutritional statuselectrolyte disturbance. chronic obstructive pulmonary disease,
hypertension, and coronary artery disease, should be assessed.
Intraoperative considerations
Major surgeries involve potential for blood loss.Monitoring including intra-arterial blood pressure and
central venous pressure should be strongly considered.CVP lines should be placed in anticubital or femoral veinSurgical manipulation around carotid sinus can produce
reflex bradycardia or even asystoleIn the above case surgery should be stopprd and
resustication startedLocal infiltration of lignocaine can also be done
prophlactically.
Some degree of hypotension is usually requiredCan be achieved with inhaled agents and a 10-
to 15-degree head-up tilt aiming for systolic blood pressures of around 85 to 90 mm Hg.
A remifentanil infusion also is very effective in controlling the stress response during surgery
HEAD AND NECK DIFFICULT AIRWAYCaused by numerous disease states at different
levels within the airwayNo single anesthetic management technique can
be used safely in all patients.
LEVEL OF OBSTRUCTION:(1) Oral cavity(2) Oropharynx (3)(3) Tongue base and supraglottis(4) Glottis(5) Subglottic and upper trachea(6) Midtracheal (7) Lower tracheal and bronchial.
Oral Cavity and Oropharyngeal LesionsSmall oral lesions such as tonsilar carcinoma
usually do not obstruct the airway.Standardised airway management rechniques
may be adequate for non compromised For larger lesions in the oral cavity, partial or
near-complete airway obstruction can be a feature
Iv induction causes loss of airway toneLarge lesions cause an inability to oxygenate
hence facemask may not be helpful
Passage of an oral or nasal airway past large, obstructing, vascular, necrotic oral tumors causes trauma and bleeding
An awake fiberoptic intubation technique is often used in this group of patients
Other anesthetic techniques include awake transtracheal catheter placement with jet ventilation and awake tracheostomy
Abscess and Ludwig's Angina:Minor abscess causes pain and swelling only.Abscesses around the peritonsillar area also may
lead to airway compromise with obstruction, trismus, dysphagia, and severe pain.
Aspiration under local anesthetic may be possible, but extensive surgery may need to be done under general anesthesia
For patients without airway compromise, an intravenous induction with careful laryngoscopy and tracheal intubation, avoiding rupture of the abscess, can be done
If airway compromise or anatomic distortion is present, an awake fiberoptic nasotracheal intubation technique or tracheostomy under local anesthetic indicated.
Tongue Base and Supraglottic LesionsEven small lesions can have significant effect on
the airwayDanger from IV induction is loss of supportive
tone.An oral or nasal airway may be ineffective in
relieving the obstructionAn oral or nasal airway may be ineffective in
relieving the obstructionA strong jaw thrust maneuver may be required
Standard curved blade laryngoscopy can traumatize any lesion at the tongue base and valleculae
Straight blade may also be ineffective in distorted epiglottis
In pts with suspected supraglottic airway compromise-
awake fiberoptic intubationawake transtracheal catheterawake laryngeal block with direct laryngoscopy an awake local anesthetic tracheostomy
Glottic LesionsLaryngeal pathology with T1,T2 lesions can be
managed with conventional airway management techniques-
IV induction with cuffed ET tube“ tracheostomy tubeSupraglottic and subglottic jet ventilation for
biopsy
Options limited in advanced lesions or airway compromise
Awake fiberoptic intubation techniques have an associated morbidity and mortality
Inhaled induction for advanced laryngeal tumors with airway obstruction is difficult and challenging
Induction is slow with apneic periods, and episodes of obstruction are common.
The administration of a muscle relaxant provides optimal ventilation and intubating conditions
At a suitable depth of anesthesia, laryngoscopy is undertaken
Smaller sized ET tubes must be readyA gum elastic bougie or stylet may be useful.Failure to intubate requires an urgent
tracheostomy, and the surgeon should be gowned and immediately ready.
Transtracheal catheter placementUnder local anesthesia Catheter is placed usually at the level of the
second or third tracheal rings, avoiding the tumor and the risk of bleeding and tumor seeding.
Intravenous induction is startedJet ventilation through the transtracheal
catheter is begun