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Oxford Handbook of Anaesthesia (3 ed.)

Edited by Keith Allman, Iain Wilson

Publisher:
Oxford University Press
Print Publication Date:
Jul 2011
Print ISBN-13:
9780199584048
Published to Oxford Medicine:
Sep 2011
DOI:
10.1093/med/9780199584048.001.0001

Disclaimer

Oxford University Press makes no representation, express or implied, that the drug dosages in this book are correct. Readers must therefore always check the product information and clinical procedures with the most up to date published product information and data sheets provided by the manufacturers and the most recent codes of conduct and safety regulations. The authors and the publishers do not accept responsibility or legal liability for any errors in the text or for the misuse or misapplication of material in this work. Except where otherwise stated, drug dosages and recommendations are for the non-pregnant adult who is not breastfeeding.

Contents

Ear, nose, and throat surgery

Chapter:
Ear, nose, and throat surgery
DOI:
10.1093/med/9780199584048.003.0025

  • Fred Roberts

    General principles [link]

  • Preoperative airway obstruction [link]

  • Obstructive sleep apnoea [link]

  • Grommet insertion [link]

  • Tonsillectomy/adenoidectomy: child [link]

  • Tonsillectomy in adults [link]

  • Myringoplasty [link]

  • Stapedectomy/tympanoplasty [link]

  • Nasal cavity surgery [link]

  • Microlaryngoscopy [link]

  • Tracheostomy [link]

  • Laryngectomy [link]

  • Pharyngectomy [link]

  • Radical neck dissection [link]

  • Parotidectomy [link]

  • Other ENT procedures [link]

  • See also:

  • Cleft lip and palate repair [link]

General principles

Airway problems are the major concern in ear, nose, and throat (ENT) surgery, related to both the underlying clinical problem and the shared airway.

Presenting pathology may:

  1. • Produce airway obstruction

  2. • Make access difficult or impossible.

Surgeons working in or close to the airway can:

  1. • Displace or obstruct airway equipment

  2. • Obscure the anaesthetist's view of the patient

  3. • Limit access for the anaesthetist during operation

  4. • Produce bleeding into the airway (intra- and postoperatively).

The surgeon and anaesthetist should plan together to use techniques/ equipment that provide good conditions for surgery whilst maintaining a safe, secure airway. Whenever an airway problem is suspected intraoperatively, correcting it is the first priority, stopping surgery if necessary. Other structures around the head are inaccessible during surgery and need protection—especially the eyes. Ensure they are kept closed with appropriate tape, padded as necessary, and that pressure from equipment is prevented, especially for long cases.

Airway/ventilation management

ETT or LMA

  1. • Traditionally an endotracheal tube (ETT) has been used for airway protection for the majority of ENT work.

  2. • Preformed RAE (Ring, Adair, Elwyn) tubes provide excellent protection with minimal intrusion into the surgical field.

  3. • An oral (south-facing) RAE tube is used for nasal and much oral surgery, although a nasal tube (north-facing) allows better surgical access to the oral cavity.

  4. • The laryngeal mask airway (LMA) or equivalent supraglottic airway is increasingly being used, usually of the reinforced flexible type. It offers adequate protection against aspiration of blood or surgical debris and reduces complications of tracheal intubation/extubation. It restricts surgical access to a greater degree, however, and is more prone to displacement during surgery (with potentially catastrophic results).

SV or IPPV

  1. • Neuromuscular blockade (NMB) is not required for most ENT surgery.

  2. • Many ENT anaesthetists still favour spontaneous ventilation (SV), regarding movement of the reservoir bag as a valuable sign of airway integrity.

  3. • If SV is used via an ETT, suxamethonium produces the best conditions for intubation, but side effects are troublesome, particularly myalgia in a population where early ambulation is likely. Alternatives include mivacurium, combinations of high-dose propofol and alfentanil/ remifentanil, and deep inhalational anaesthesia.

  4. • IPPV enables faster recovery and return of airway reflexes.

Deep or light extubation

  1. • Many ENT procedures create bleeding into the airway. Suction (and pack removal) under direct vision before extubation is essential in such cases, taking care not to traumatise any surgical sites.

  2. • One particular danger site for blood accumulation is the nasopharynx behind the soft palate, an area not readily visible. Blood pooling here can be aspirated following extubation, with fatal results (‘Coroner's clot’). It is best cleared using either a nasal suction catheter or a Yankauer sucker rotated so its angled tip is placed behind the uvula.

  3. • Laryngospasm can follow extubation, particularly in children, from recent instrumentation of the larynx or irritation by blood. The risk is minimised by extubating either deep or light (not in-between).

  4. • Deep extubation is best suited to SV. At the end of surgery, continue or even increase the volatile agent concentration, but change gases to 100% oxygen (to increase the FRC store). After careful suction, insert a Guedel airway, turn patient left lateral/head down (tonsil position), check respiration is regular (turning can produce transient coughing/breath holding), then extubate.

  5. • Check airway/respiration are fine, and keep patient in this position until airway reflexes return. Since the patient remains anaesthetised in recovery, at risk of airway complications, appropriately skilled recovery staff are essential with the anaesthetist immediately available.

  6. • In the early recovery period, continuous low suction can be done via a catheter just protruding from the Guedel airway.

  7. • Light extubation is best suited to IPPV. After careful suctioning, any residual NMB is reversed, inhalational agents discontinued, and the trachea extubated after laryngeal reflexes have returned.

  8. • Light extubation often produces a brief period of coughing/restlessness initially. This is less frequent with the use of opioids.

  9. • Light extubation is recommended in all patients with a difficult airway.

Throat packs1

  1. • A throat pack (wet gauze or tampons) is often used around the ETT/LMA to absorb blood that might otherwise pool in the upper airway.

  2. • A throat pack is particularly useful during nasal operations where bleeding can be substantial and is not cleared during surgery.

  3. • The pack must be removed before extubation, as it can lead to catastrophic airway obstruction if left. Systems to ensure removal include:

    1. • Tie or tape the pack to the ETT.

    2. • Place an identification sticker on the ETT or patient's forehead.

    3. • Include the pack in the scrub nurse's count.

    4. • Always perform laryngoscopy prior to extubation.

Nasal vasoconstrictors

  1. • Vasoconstriction is used to reduce bleeding in most nasal surgery. Cocaine (4–10%) and adrenaline (1:100 000–1:200 000) are the most commonly used agents, administered by:

    1. • Spray

    2. • Paste/gel

    3. • Soaked swabs

    4. • Infiltration (not cocaine).

  2. • The recommended maximum dose of cocaine is 1.5mg/kg, though absorption from topical application is only partial. Sympathomimetic activity can result transiently after cocaine absorption.

  3. • Moffett (1947) described a mixture for topical nasal vasoconstriction consisting of:

    1. • 2ml cocaine 8%

    2. • 1ml adrenaline 1:1000

    3. • 2ml sodium bicarbonate 1%.

  4. • Moffett's solution is still used with assorted modifications, e.g. cocaine 10%, bicarbonate 8.4%, or mixed in aqueous gel.

Remifentanil

  1. • The intense opioid action of remifentanil, combined with its rapid recovery profile, has led to its growing popularity.

  2. • Normally given by infusion, clinical applications include:

    1. • Middle ear surgery/major head and neck resections (controlled arterial pressure reduces bleeding)

    2. • Parotidectomy (facilitates IPPV without relaxant)

    3. • Laryngoscopy/pharyngoscopy (attenuates hypertensive response).

  3. • Beware of bradycardia/hypotension on induction, particularly in the elderly: give a 5–10ml/kg IV fluid preload and glycopyronnium for bradycardia.

  4. • Inter-patient variability greatly limits the value of predetermined infusion schemes.

  5. • For major surgery, to prevent postoperative rebound hypertension/ agitation in recovery, continue remifentanil at a low infusion rate or give morphine 15–20min before the end of surgery: clonidine up to 150µg IV is also useful.

Preoperative airway obstruction

(See also [link])

Assessment

  1. • Patients with preoperative airway obstruction usually present for surgery either to establish the diagnosis or to relieve the obstruction.

  2. • The most common level for obstruction is the larynx, producing stridor (high-pitched, inspiratory) and markedly reduced exercise tolerance. Classified as supraglottic, glottic, or subglottic.

  3. • In adults, tumours are the commonest cause of upper airway obstruction, though haematoma or infection (including epiglottitis) is also possible. In children, infection (croup) or foreign body is more likely; in the UK, Hib vaccination has virtually eliminated childhood epiglottitis.

  4. • Extreme airway obstruction will cause obvious signs of respiratory distress at rest. Exhaustion or an obtunded conscious level indicate the need for immediate intervention.

  5. • If obstruction has a gradual onset, patients can compensate very effectively and moderately severe obstruction can develop without gross physical signs. Features to help recognise a substantial degree of upper airway obstruction include:

    1. • Long, slow inspirations, with pauses during speech.

    2. • Worsening stridor during sleep (history from spouse/night nursing staff) or exercise.

  6. • Oropharyngeal lesions rarely present with airway obstruction and assessment is normally straightforward on preoperative examination. Important features are limitation of mouth opening and tongue protrusion, and identification of any masses compromising the airway.

  7. • Useful information may come from radiographs (plain films, CT/MRI) or ENT clinic flexible or indirect laryngoscopy.

Management

  1. • For life-threatening airway obstruction emergency intervention may be needed, but usually surgery will be a planned procedure.

  2. • For emergencies, avoid undue delays. Whilst preparing theatre, helium by facemask (FM) can improve flow past the obstruction (low density favourable for turbulent flow), though this must not delay definitive management. Medical helium comes premixed (79%) with oxygen (21%): additional oxygen should be added via a Y connector.

  3. • The main problems in securing airway access are:

    1. • Airway obstruction likely to be worsened by lying the patient flat, instrumenting the larynx, or general anaesthesia (all techniques).

    2. • Identifying the laryngeal inlet may be difficult because of anatomical distortion (especially supraglottic lesions).

    3. • Severe stenosis may make passage of tube difficult (particularly glottic or subglottic tumours).

  4. • There is little evidence to support any one particular anaesthetic technique. However, the use of IV induction agents or NMB carries the catastrophic risk of ‘can't intubate/can't ventilate’ in a patient unable to breathe spontaneously.

  5. • The three main options for establishing secure airway access are:

    1. • Direct laryngoscopy/tracheal intubation under deep inhalational anaesthesia using sevoflurane or halothane.

    2. • Tracheal intubation under local anaesthesia (LA) using fibreoptic laryngoscopy.

    3. • Tracheostomy under LA (or deep inhalational general anaesthesia with FM or LMA in less severe cases).

  6. • Fibreoptic intubation under LA may be difficult with stenotic lesions as the airway may be completely blocked by the scope during the procedure.

  7. • Mason and Fielder1 reviewed the merits of each technique for airway obstruction at different levels, but concluded none is universally certain, safe, and easy and the final decision in each case will be strongly influenced by the particular skills and experience of the anaesthetist and surgeon concerned.

  8. • Whichever technique is used, a full range of equipment should be prepared, including different laryngoscopes, cricothyroidotomy kit, and tubes in various sizes. An ETT kept on ice will be stiffer and may be useful to get past an obstructing lesion.

  9. • In children, deep inhalational anaesthesia is the only realistic option. Delays in getting to theatre must be avoided because of rapid and unpredictable decline in condition. To minimise upset in a small child, it may well be best to delay IV cannulation until after induction—usually this is best undertaken with the child sitting, being comforted by a parent. A moderate degree of CPAP is very effective at keeping the airway patent as anaesthesia deepens. Once deep, and if stable, LA spray to the larynx can be helpful in extending the available time for laryngoscopy before airway reflexes return. In epiglottitis, distortion of the epiglottis can make recognition of the glottis very difficult; a useful tip is to press on the child's chest and watch for a bubble of gas emerging from the larynx.

  10. • If complete airway obstruction occurs and all conventional attempts to secure the airway fail, emergency surgical access to the airway is the only option. Cricothyroidotomy is preferable to tracheostomy for emergency airway access, as it is quicker to perform, more superficial, and less likely to bleed (above the thyroid gland). (See [link].)

Obstructive sleep apnoea

(see [link])

  1. • Obstructive sleep apnoea (OSA)1 is the most common form of sleep apnoea syndrome. The airway obstructs intermittently because of inadequate muscle tone/coordination in the pharynx. The problem usually occurs in association with other factors such as obesity.

  2. • In adults, surgery for OSA may include nasal operations and uvulopalatopharyngoplasty (UPPP), although the role of UPPP in OSA is controversial as it may render nasal CPAP less effective in the long term.

  3. • In children, OSA usually results from extreme adenotonsillar hypertrophy, and adenotonsillectomy is performed to relieve this.2

  4. • OSA produces total obstruction with repeated episodes of hypoxia leading to arousal (though not awakening). Multiple episodes can occur each night, with oxygen saturation falling repeatedly to below 50%.

  5. • Repeated interruptions to sleep produce daytime lethargy and somnolence, whilst extensive nocturnal hypoxia can lead to pulmonary or systemic hypertension with ventricular hypertrophy and cardiac failure.

  6. • A careful history (from the partner or parent) is the most valuable information initially. In OSA, snoring is interrupted by periods of silent apnoea broken by a ‘heroic’ deep breath.

  7. • Sleep studies reveal the extent of apnoea. If a history unexpectedly gives a clear picture of OSA consider patient referral.

  8. • In children with suspected OSA, features of chronic hypoxaemia should be sought. These include polycythaemia and right ventricular strain (large P wave in leads II and V1, large R wave in V1, deep S wave in V6). If features exist, echocardiography and referral for sleep studies should be considered. In severe cases, corrective otolaryngological surgery should be undertaken before unrelated elective surgery.

  9. • Perioperatively the biggest danger is impairment of respiratory drive and hypoxic arousal mechanisms by the sedative action of drugs.

  10. • Anaesthetic management is aimed at minimising periods of sedation and ensuring that ventilation and oxygenation are maintained until the patient is adequately recovered. Specific points include:

    1. • Avoidance of preoperative sedative drugs.

    2. • Intubation is usually not a problem unless other factors are present.

    3. • Long-acting opioids should be avoided if possible. Use NSAIDs, paracetamol, tramadol, or local infiltration where feasible.

    4. • When needed, long-acting opioids should be given IV and titrated carefully against response (around 50% normal dose requirement).

    5. • Close overnight monitoring (including pulse oximetry). Admission to HDU or even ITU may be necessary.

    6. • For nasal surgery a nasopharyngeal airway can be incorporated into the nasal pack and left in place overnight.

Grommet insertion

Procedure

Myringotomy and grommet insertion, usually bilateral

Time

5–15min

Pain

+

Position

Supine, head tilted to side, head ring

Blood loss

Nil

Practical techniques

FM or LMA

SV using T-piece

Preoperative

  1. • Usually children (1–8yr), day case if sole procedure.

  2. • Repeated ear infections, check for recent URTI.

Perioperative

  1. • FM suitable if surgeon happy to work round it, but assistant needed to adjust vaporiser, etc. Insert Guedel airway before draping and ensure reservoir bag visible throughout (T-piece ideal if facemask used).

  2. • LMA is popular.

Postoperative

PRN paracetamol or diclofenac oral/PR—many need no analgesia.

Special considerations

  1. • If FM airway difficult, change early to LMA.

  2. • Reflex bradycardia occasionally seen related to partial vagal innervation of tympanic membrane.

Tonsillectomy/adenoidectomy: child

Procedure

Excision of lymphoid tissue from oropharynx (tonsils) or nasopharynx (adenoids)

Time

20–30min

Pain

+++

Position

Supine, pad under shoulders

Blood loss

Usually small, can bleed post-op

Practical techniques

South-facing uncuffed RAE tube or reinforced LMA, placed in groove of split blade of Boyle–Davis gag

SV or IPPV

Preoperative

  1. • Careful history to exclude OSA (see [link]) or active infection.

  2. • Topical local anaesthesia on hands (mark sites of veins).

  3. • Consent for PR analgesia.

Perioperative

  1. • IV or inhalational induction (sevoflurane)—Guedel airway useful if nasopharynx blocked by large adenoids.

  2. • Intubate (uncuffed RAE) using relaxant or deep inhalational anaesthesia or insert LMA using propofol/opioid or deep inhalational anaesthesia.

  3. • Secure in midline, no pack (obscures surgical field).

  4. • Beware surgeon displacing/obstructing tube intraoperatively, particularly after insertion or opening of Boyle–Davis gag.

  5. • T-piece ideal for SV, but ensure reservoir bag always visible.

  6. • Reliable IV access essential, though IV fluids not routine.

  7. • Analgesia with diclofenac/paracetamol PR, morphine or pethidine IV/IM.

  8. • Careful suction of oropharynx and nasopharynx at end under direct vision (surgeon may do).

  9. • Extubate left lateral/head down (tonsil position), with Guedel airway.

Postoperative

  1. • Keep patient in tonsil position until airway reflexes return.

  2. • High-quality recovery care essential.

  3. • Analgesia with PRN paracetamol or diclofenac oral/PR, morphine or pethidine IV/IM.

  4. • Leave IV cannula (flushed) in place in case of bleeding.

Special considerations

  1. • In small children, a pillow under the chest can be used to provide necessary tilt.

  2. • Avoid blind pharyngeal suction with rigid sucker as this may start bleeding from tonsil bed.

  3. • NSAIDs increase bleeding slightly (especially if given preoperatively)1this needs to be balanced against benefits.

  4. • LA infiltration of tonsil bed is not recommended.

  5. • Beware continual swallowing in recovery, a sign of bleeding from tonsil/adenoid bed.

  6. • Adenoidectomy/tonsillectomy is increasingly being done as day cases in suitable patients, with extended stay and education of parents to recognise signs of bleeding.

Variant Creutzfeldt–Jakob disease

(see [link])

  1. • Prions, which accumulate in lymphoid tissue such as the tonsils and adenoids, are not reliably destroyed during standard methods of surgical sterilisation. Inter-patient transmission of prion-borne conditions, such as variant Creutzfeldt-Jakob disease (vCJD), via theatre equipment contaminated during tonsillectomy/adenoidectomy is therefore a potential risk, although the predicted epidemic of vCJD has not materialised.

  2. • In January 2001 the UK Department of Health issued guidelines that all relevant surgical and anaesthetic equipment used for tonsillectomy/ adenoidectomy should be single-use.

  3. • An increased risk of haemorrhage associated with disposable instruments led to the removal of this guideline for surgical equipment.

  4. • In the UK the single-use guideline remains in place, however, for all anaesthetic equipment that is placed in the mouth, such as ETTs and LMAs. The guideline also recommends sheathed or single-use laryngoscope blades, although it is difficult to see how a laryngoscope used solely at the start of a case represents a greater contamination risk in this context than for any other operation.

Bleeding after adenotonsillectomy

  1. • May be detected in recovery or many hours later.

  2. • Loss may be much greater than readily apparent (swallowed blood).

  3. • Senior anaesthetist must be involved.

  4. • Problems include:

    1. • Hypovolaemia

    2. • Risk of aspiration (fresh bleeding and blood in stomach)

    3. • Difficult laryngoscopy because of airway oedema and blood

    4. • Residual anaesthetic effect.

  5. • Resuscitate preoperatively, check Hb (HemoCue® ideal), crossmatch, and give blood as needed. Note: Hb will fall as IV fluids administered (dilution).

  6. • Options:

    1. • Rapid sequence induction: enables rapid airway protection, but laryngoscopy may be difficult (blood, swelling)—generally preferred.

    2. • Inhalational induction left lateral/head down: allows time for laryngoscopy, but takes longer and unfamiliar technique to many.

  7. • Use wide-bore gastric tube to empty stomach after bleeding stopped.

  8. • Extubate fully awake.

  9. • Extended stay in recovery for close monitoring.

  10. • Nasopharyngeal pack occasionally needed (secured via tapes through nose) if bleeding from adenoids cannot be controlled. Usually very uncomfortable—patient may need midazolam/morphine to tolerate.

  11. • Check postoperative Hb.

Tonsillectomy in adults

As for child, except:

  1. • Usually more painful postoperatively in adult—give morphine in theatre.

  2. • IPPV-relaxant technique used more commonly. Mivacurium useful with quick surgeon.

  3. • Preoperative oral NSAID avoids suppository use, though may increase bleeding risk.

  4. • Occasionally patients present with peritonsillar abscess (quinsy). Now normally treated with antibiotics and tonsillectomy performed later. If drainage essential because of airway swelling, pus usually aspirated with syringe and large needle under LA infiltration.

Myringoplasty

Procedure

Reconstruction of perforated tympanic membrane with autograft (usually temporalis fascia)

Time

60–90min

Pain

++

Position

Supine, head tilted to side, head ring, head-up tilt

Blood loss

Minimal

Practical techniques

South-facing RAE tube or LMA (usually reinforced)

SV or IPPV

Preoperative

Usually young, fit patients.

Perioperative

  1. • Ensure coughing avoided during surgery: LA spray to larynx, monitor neuromuscular block if IPPV-relaxant technique used.

  2. • Dry field improves the surgical view, though not as important as for stapedectomy—head-up tilt and avoiding hypertension/tachycardia normally sufficient.

  3. • Remifentanil infusion suitable.

  4. • Routine antiemetic useful.

Postoperative

  1. • PRN paracetamol or diclofenac oral/IV; may need morphine.

  2. • PRN antiemetic.

Special considerations

Using nitrous oxide may produce diffusion into middle ear and risk graft lifting off: less important with advances in surgical technique and the use of remifentanil—discuss with surgeon.

Stapedectomy/tympanoplasty

Procedure

Excision/reconstruction of damaged middle ear

structures

Time

2–4hr

Pain

++/+++

Position

Supine, head tilted to side, head ring, head-up tilt

Blood loss

Minimal

Practical techniques

South-facing RAE tube or LMA (usually reinforced)

IPPV normally

Arterial line often used

Preoperative

  1. • Check for cardiovascular disease, as this will limit degree of hypotension possible.

  2. • Oral premedication options include benzodiazepines, β-blockers, and clonidine.

Perioperative

  1. • Monitor to ensure adequate neuromuscular block.

  2. • Bloodless field enables greater surgical accuracy—simple measures include: potent opioid preinduction, ensure coughing avoided at intubation (LA spray to larynx helpful), head-up tilt to reduce venous pressure.

  3. • Further benefit achieved by lowering arterial BP (mean of 50–60mmHg in healthy patients) and HR (<60bpm).

  4. • Remifentanil infusion ideal to achieve this. Alternatively, use IV β-blocker (metoprolol 1mg increments, esmolol infusion) plus vasodilator (isoflurane, hydralazine, phentolamine): IV labetalol (combined α/β-blocker, 5mg increments) also used, though less individual control of HR and BP.

  5. • Arterial line strongly advised with cardiovascular disease or if potent vasodilators used: head-up tilt further reduces perfusion pressure to brain.

  6. • Give antiemetic routinely.

Postoperative

  1. • Regular antiemetic for 24–48hr.

  2. • PRN paracetamol or diclofenac oral/IV/PR; may need morphine.

Special considerations

  1. • N2O diffusion into middle ear may disrupt surgery, though less important than in myringoplasty. Either avoid (reduction in PONV) or use until 20min before end of case, then discontinue.

Nasal cavity surgery

Procedure

Submucous resection (SMR) of septum, septoplasty, turbinectomy, polypectomy, functional endoscopic sinus surgery (FESS)

Time

20–60min

Pain

++

Position

Supine, head ring, head-up tilt

Blood loss

Usually minor

Practical techniques

South-facing RAE tube or LMA (usually reinforced)

SV or IPPV

Throat pack

Preoperative

  1. • Obstructive airways disease often associated with nasal polyps.

  2. • Combination of above procedures frequently performed.

Perioperative

  1. • Facemask ventilation often needs Guedel airway due to blocked nose.

  2. • Nasal vasoconstrictor usually applied (LA/adrenaline infiltration, cocaine spray/paste, Moffett's solution).

  3. • Leave eyes untaped for polypectomy (optic nerve can be close and surgeon needs to check for eye movement).

  4. • Suck out pharynx (particularly behind soft palate—‘Coroner's clot’ see [link]) before extubation: less easy with LMA.

Postoperative

  1. • Left lateral/head down with Guedel airway in place until airway reflexes return.

  2. • Analgesia with PRN paracetamol or diclofenac oral/IV/PR.

  3. • Nose usually packed producing obstruction of nasal airway—if disturbing to patient, or in cases of OSA, nasopharyngeal airway(s) can be incorporated into the pack.

  4. • Sit patient up as soon as awake to reduce bleeding.

Special considerations

  1. • Leave IV cannula in overnight, as can bleed postoperatively.

Microlaryngoscopy

Procedure

Examination of larynx using operating microscope (+ excision/biopsy)

Time

10–30min

Pain

+/++

Position

Supine, pad under shoulders, head extended

Blood loss

Nil

Practical techniques

Microlaryngeal tube and conventional IPPV

TIVA and jet ventilation using injector system (O2 + entrained air) via:

  • • injector needle on the operating

  • laryngoscope

  • • semi-rigid tracheal catheter

  • • cricothyroidotomy needle/cannula

Ventilation during microlaryngoscopy

Microlaryngeal tube and conventional IPPV

  1. • Microlaryngeal tube is a long 5.0mm ETT with a high-volume/ low-pressure cuff.

  2. • Enables maintenance of anaesthesia with inhalational agents.

  3. • Protects against aspiration of blood/surgical debris but restricts surgeon's view.

  4. • Use long, slow inspiration for IPPV because of high resistance of tube. Measured inflation pressure will be high, but patient's airway pressures distal to tube will be lower.

Jet ventilation

  1. • Ventilation achieved using an injector system, such as the adjustable-flow Manujet®, delivering O2 and entrained air via:

    1. • Injector needle attached to proximal end of operating laryngoscope and ventilation started when correctly aligned with larynx. Various needle sizes available with different flow rates. Technique not suitable if good view of larynx is unobtainable and has disadvantage of blowing debris/smoke into trachea with ventilation.

    2. • Semi-rigid tracheal catheter (ordinary suction catheter not suitable) with tip placed mid-way down the trachea. Special catheters available with gas sampling port or made from laser-proof material.

    3. • Cricothyroidotomy needle/cannula placed through cricothyroid membrane under LA before induction and aimed towards carina. Commercial versions available or Tuohy needle can be used: beware gas injected into tissues if needle misplaced/displaced.

  2. • Induce in theatre or use microlaryngeal tube initially, then remove and change to jet ventilation when all ready in theatre (not with cricothyroidotomy needle).

  3. • Ensure anaesthetic machine in theatre is situated close to enable easy FM ventilation at induction/recovery.

  4. • TIVA needed for maintenance (propofol/remifentanil infusion).

  5. • Ventilate using normal respiratory rate and adjust inspiratory flow (alter injector settings or change needle size) to produce appropriate degree of chest expansion.

  6. • Accurate flow/pressure measurement not easy: barotrauma a potential risk.

  7. • Stop ventilation intermittently during surgical work (clear communication essential).

  8. • Provides minimal obstruction to surgical view.

  9. • At end of case, either continue jet ventilation until SV re-established or discontinue and ventilate by FM until SV recommences.

Preoperative

  1. • Patients often elderly and usually smokers; CVS/RS problems common.

  2. • Carefully assess airway for evidence of obstruction. History, examination, ENT clinic assessment, plain films, and CT scan may all help, but if any degree of stridor present obstruction must be substantial (see [link]).

  3. • Ensure all equipment is ready before induction, including cricothyroidotomy kit, and that surgeon is available for emergency tracheostomy if required.

Perioperative

  1. • If airway obstruction suspected, secure airway initially using principles on [link]. Inserting a cricothyroid cannula under LA preinduction provides a route for ventilation in the event of total obstruction.

  2. • Give short-acting opioid (alfentanil, remifentanil) to attenuate hypertensive response.

  3. • Muscle relaxation is usually essential: mivacurium or intermittent suxamethonium (+ glycopyronnium/atropine to prevent bradycardia).

  4. • Use of rocuronium and reversal with sugammadex may be an option.

  5. • LA spray to larynx reduces risk of laryngospasm, though this impairs airway protection, so recover left lateral, head down.

Postoperative

  1. • Analgesia with PRN paracetamol or diclofenac oral/IV/PR.

  2. • May develop stridor postoperatively from oedema of an already-compromised airway—dexamethasone 8–12mg IV sometimes used to prevent this.

Special considerations

  1. • Jet ventilation essential if laser work planned.

  2. • Microlaryngoscopy can be used to inject inert material (Teflon®) into paralysed vocal cords to improve phonation, though this can lead to airway obstruction if overdone.

  3. • High-frequency jet ventilation has been used, though complex and assessment of ventilation difficult.

Tracheostomy

Procedure

Insertion of a tracheal tube via neck incision

Time

30min

Pain

++

Position

Supine, pad under shoulders, head ring, head-up tilt

Blood loss

Normally small, though can bleed from thyroid vessels

Practical techniques

IPPV, ETT with tubing going ‘north’, changed to tracheostomy tube during case

LMA if airway not a problem, IPPV or SV

Can be done under LA

Preoperative

  1. • Normally done for long-term ICU ventilation or airway obstruction.

  2. • ICU patients almost certainly already intubated. If ventilation difficult and oxygenation critical, set up ICU ventilator in theatre, using TIVA rather than inhalational agents.

  3. • Stop NG feeds if applicable.

  4. • If tracheostomy is for airway obstruction, secure airway initially using principles on [link].

  5. • Before induction ensure all equipment prepared (including cricothyroidotomy kit) and surgeon ready for emergency tracheostomy if required.

Perioperative

  1. • Secure ETT with tape to allow easy removal during case, with pilot cuff readily accessible.

  2. • Aspirate NG tube (if present) and clear oropharynx of secretions before draping.

  3. • Drape patient to allow anaesthetist access to ETT for tube change.

  4. • Long tubing needed for breathing circuit and gas sampling.

  5. • Before changing to tracheostomy tube, preoxygenate for 3–4min (increasing volatile agent as necessary) and check neuromuscular blockade is adequate.

  6. • Ensure scrub nurse has correct tracheostomy tube and sterile catheter mount.

  7. • Deflate ETT cuff before surgeons incise trachea, so it can be reinflated and ventilation continued if problems occur.

  8. • Withdraw ETT slowly into upper trachea (do not remove from trachea until tracheostomy secure and certain) and connect breathing circuit and capnograph to new tracheostomy tube via sterile catheter mount.

  9. • Beware false passage created during tracheostomy tube insertion, especially in the obese: check position with fibreoptic endoscopy if any doubt.

  10. • If problems occur, remove tracheostomy tube and advance ETT back down trachea.

Postoperative

  1. • Regular suction to new tracheostomy (blood, secretions).

  2. • Humidify inspired gases.

  3. • Analgesia in recovery with diclofenac IV/PR or morphine IV. Usually little analgesia required thereafter.

  4. • A new tracheostomy often produces protracted coughing—morphine, benzodiazepines, or low-dose propofol useful for control.

  5. • Antiemetic as required.

  6. • If tube comes out, reinsertion can very difficult in first few days—orotracheal intubation often more practical. Two retraction sutures left in tracheal incision are useful for identifying and opening the stoma.

Special considerations

  1. • Can be done under LA, though difficult in a dyspnoeic, struggling patient.

  2. • In ICU tracheostomy is now commonly done percutaneously using dilatational technique: theatre cases are likely to be the difficult ones.

  3. • Tracheostomy is not the ideal route of approach for emergency airway access: cricothyroidotomy is more accessible and less likely to bleed.

  4. • LMA can be used if tracheostomy is done at start of larger procedure and upper airway normal.

Tracheostomy tubes

  1. • Specific features available include:

    1. • Fenestration: allows speech by occluding lumen with finger and exhaling through hole in back wall of tube.

    2. • Inner tube (e.g. Shiley®): permits removal for cleaning.

    3. • Adjustable flange: length can be modified for short trachea or deep stoma.

    4. • Channel in obturator for guide-wire.

  2. • Tube change:

    1. • New tube must be inserted with obturator in place to prevent stomal damage.

    2. • May be difficult to find trachea in new tracheostomy: guide-wire very useful.

    3. • Prepare for orotracheal intubation in case of problems.

    4. • Cannot be left in place longer than 28d (classified as an implant thereafter).

Laryngectomy

Procedure

Excision of larynx (epiglottis and glottis) with creation of an end-stomal tracheostomy

Time

3–4hr

Pain

+++

Position

Supine, pad under shoulders, head ring, head-up tilt

Blood loss

Moderate to substantial; X-match 2–4U

Practical techniques

IPPV, ETT with tubing going ‘north’, changed to tracheostomy during case

Art line, urinary catheter, CVP line if surgery likely to be long/complicated or if indicated by cardiac disease

Preoperative

  1. • Some degree of airway obstruction likely. Patient likely to have had recent GA (for diagnosis) to guide airway management: beware if some time has elapsed.

  2. • If no recent GA, assess the airway as for microlaryngoscopy ([link]).

  3. • Usually smokers: CVS/respiratory system problems and malnutrition common.

  4. • Discuss implications of tracheostomy preoperatively (communication, secretions, coughing produced by tube). Speech therapist will do much of this.

Perioperative

  1. • Insert fine-bore NG feeding tube at induction and fix securely (can be sutured to nasal septum).

  2. • Warming blanket and fluid warmer.

  3. • Long tubing needed for breathing circuit and gas sampling tube.

  4. • Remifentanil infusion ideal.

  5. • Substantial blood loss can accumulate under drapes at back of neck and may not be apparent until end of case.

  6. • For CVP access, all neck lines hinder surgery: femoral best, though antecubital fossa (ACF) or subclavian can be used.

  7. • Antibiotic prophylaxis for at least 24hr.

  8. • When changing to tracheostomy tube, see precautions for tracheostomy ([link]), though end-stoma makes tracheal access safer and easier.

  9. • During surgery, long tube (armoured or special preformed) via tracheostomy is useful to enable surgical access round stoma—beware endobronchial intubation.

Postoperative

  1. • HDU ideal.

  2. • Humidification and regular suction essential (blood, secretions).

  3. • New tracheostomy produces protracted coughing—morphine, benzodiazepines, or low-dose propofol useful for control.

  4. • Analgesia with PRN diclofenac IV/PR, morphine IV/IM/SC. Suitable for PCA, although analgesic requirements are surprisingly low. Paracetamol suspension (via NG tube) useful after initial postoperative period.

  5. • Antiemetic as required.

Special considerations

  1. • Beware of air emboli during dissection—early detection by sudden fall in ETCO2.

  2. • For previous laryngectomy patients presenting for surgery, to ventilate via stoma use paediatric facemask turned through 180°, LMA applied to neck, or intubate awake after LA spray to stoma. Tracheostomy tube insertion is usually easy, though check stoma for stenosis or tumour recurrence and always preoxygenate.

  3. • Partial laryngectomy, with laryngeal reconstruction and temporary tracheostomy, favoured by some as alternative to radiotherapy in early laryngeal tumours.

Pharyngectomy

Procedure

Excision of pharynx (includes glossectomy and radical tonsillectomy): may involve mandibular split for access and tissue transfer

Time

6–8hr

Pain

++++

Position

Supine, pad under shoulders, head ring, head-up tilt

Blood loss

Major; X-match 4U initially

Practical techniques

IPPV, ETT (nasal may be best) with tubing going ‘north’ initially, changed to tracheostomy during case

Art line, CVP line, urinary catheter

Preoperative

  1. • Discuss plans with surgeons to ensure what needs to be left untouched, e.g. forearm flap.

  2. • Assess airway carefully: patient likely to have had recent GA (for diagnosis) to guide airway management.

  3. • CVS/respiratory system problems and malnutrition common.

  4. • Inform patient about lines, tracheostomy, etc.

  5. • Ensure ICU bed available.

Perioperative

  1. • Insert fine-bore NG feeding tube at induction and fix securely (can be sutured to nasal septum).

  2. • Femoral route best for CVP access.

  3. • Long tubing needed for breathing circuit and gas sampling tube.

  4. • Warming blanket and fluid warmer.

  5. • Access to patient severely restricted: ensure all lines/tubes secure at start.

  6. • Remifentanil infusion ideal.

  7. • Substantial blood loss may be hidden under drapes: check regular HemoCue®.

  8. • Ensure patient is well-filled, especially if free-flap used (aim for Hb of ∼10g/dl)—see [link].

  9. • Antibiotic prophylaxis for at least 24hr.

Postoperative

  1. • ICU essential.

  2. • Keep sedated and ventilated until stable and warm.

  3. • Regular flap observations.

  4. • Avoid tracheostomy ties round neck (may compromise flap blood supply).

  5. • Humidification and regular suction (blood, secretions) to tracheostomy.

  6. • Analgesia with PCA morphine once awake and PRN diclofenac/ paracetamol NG/IV/PR.

  7. • Antiemetic as required.

Radical neck dissection

Procedure

Excision of sternomastoid, internal and external jugular veins, and associated lymph nodes.

Modified or selective neck dissection preserves some of these structures (notably IJV)

Time

2–4hr

Pain

+++

Position

Supine, pad under shoulders, head on ring tilted to side, head-up tilt

Blood loss

Moderate to substantial, X-match 2–4U

Practical techniques

IPPV, ETT with tubing going ‘north’

Art line, urinary catheter, CVP line if surgery likely to be long/complicated or with cardiac disease

Preoperative

  1. • Assess airway carefully, as may be an associated head and neck tumour or previous major surgery.

  2. • May be performed with another procedure, e.g. laryngectomy.

Perioperative

  1. • Warming blanket and fluid warmer.

  2. • Long tubing is needed for the breathing circuit and gas sampling.

  3. • Remifentanil infusion ideal.

  4. • Can bleed briskly from large neck vessels, with substantial accumulation of blood under drapes (that may not be apparent until end of case).

  5. • For CVP access femoral is best. Must avoid remaining jugulars, as head and neck venous drainage dependent on them.

Postoperative

  1. • Head and neck oedema likely for several days (impaired venous drainage). Keep head up as much as possible and avoid excessive IV fluids.

  2. • To reduce chance of agitation/rebound hypertension and wound haematoma in recovery, continue remifentanil at a low infusion rate or give morphine 15–20min before end of surgery: clonidine up to 150µg IV also very useful. Treat any hypertension early.

  3. • Analgesia with PRN paracetamol or diclofenac oral/IV/PR, morphine IV/IM. Surprisingly low analgesic requirements normally.

  4. • Antiemetic as required.

Special considerations

  1. • Beware of air emboli during dissection—early detection by sudden fall in ETCO2.

  2. • Surgical manipulation of carotid sinus can produce marked bradycardia.

  3. • If neck dissection previously done on other side, oedema is usually worse and can raise ICP. Dexamethasone 8–12mg IV preoperatively (then 4mg IV 6-hourly) is used by many to reduce this.

Parotidectomy

Procedure

Excision of parotid gland, usually preserving facial nerve

Time

2–5hr

Pain

++/+++

Position

Supine, head ring, head tilted to side and moderately extended, head-up tilt

Blood loss

Usually small/moderate, G&S. Greater for malignancy

Practical techniques

South-facing RAE tube and IPPV normally used, though SV possible for suitable patients

Reinforced LMA and IPPV or SV also possible

No NMB during dissection

Preoperative

  1. • Check if suitable for SV—not if elderly, obese, or respiratory disease.

  2. • Check mouth opening, especially if malignant.

Perioperative

  1. • Warming blanket and fluid warmer, plus urinary catheter if prolonged.

  2. • Avoid neuromuscular blockade (NMB) after initial dose (check recovery with PNS).

  3. • Remifentanil infusion ideal to allow IPPV without NMB and also reduce blood loss.

  4. • Alternatively suppress respiratory drive with other opioid, volatile agent, or propofol infusion combined with moderate hyperventilation.

  5. • LA spray to larynx useful to prevent coughing.

  6. • If SV used, ensure patient settled initially using high level of volatile agent.

Postoperative

  1. • To reduce chance of agitation/rebound hypertension and wound haematoma in recovery, continue remifentanil at a low infusion rate or give morphine 15–20min before end of surgery, keep head up, and treat hypertension early: clonidine up to 150µg IV is very useful.

  2. • Antiemetic as required.

  3. • Analgesia with PRN morphine IV/IM, paracetamol or diclofenac oral/IV/PR.

Special considerations

  1. • Surgeon normally uses nerve stimulator to identify facial nerve during dissection and may wish to leave ipsilateral eye exposed to monitor response. Avoid prolonged NMB—initial dose has usually worn off in time for surgical dissection.

  2. • Large-bore IV access at start, as can bleed substantially (especially malignant tumours).

Other ENT procedures

Operation

Description

Time (min)

Pain

Position

Blood loss

Notes

Mastoidectomy

Clearance of cholesteatoma from mastoid cavity

90–120

++

Head-up tilt, head tilted to side on ring

Minimal

RAE tube or LMA, SV, or IPPV. Bloodless field needed (see stapedectomy). If disease close to facial nerve, surgeon may request no relaxant used (see parotidectomy)

Drilling of ear exostoses

Excision of external auditory (‘swimmer's’) exostoses

60–90

++

Head-up tilt, head tilted to side on ring

Minimal

RAE tube or LMA, SV, or IPPV

BAHA

Application of bone-anchored hearing aid

90–120

++

Head-up tilt, head tilted to side on ring

Minimal

LA + sedation or GA with RAE tube or LMA, SV, or IPPV

MUA nose

Correction of nasal fracture

1–15

+

Supine

Small

If quick, preoxygenate + propofol only. If longer, RAE tube or reinforced LMA + throat pack. Occasionally bleeds dramatically

Removal of foreign body from nose

Removal of foreign body from nose, usually in child

5–10

Supine, head ring

Nil

Gas induction, RAE tube or LMA, throat pack, SV. Avoid FM ventilation if possible (risk of pushing FB down into lower airway)

Rhinoplasty

Cosmetic alteration or reconstruction of nose using bone/cartilage graft

60–90

++

Head-up tilt, head ring

Small

RAE tube or reinforced LMA, SV, or IPPV, throat pack. Moderate hypotension useful to decrease bleeding

Lateral rhinotomy

Resection of nasal tumour via lateral rhinotomy

90

++

Head-up tilt, head ring

Moderate

RAE tube or reinforced LMA, SV, or IPPV, throat pack. Moderate hypotension useful to decrease bleeding

Uvulo-palato-pharyngoplasty (UPPP)

Excision of uvula and lax tissue from soft palate, sometimes using laser

20–30

+++

Supine, pad under shoulders

Small

RAE tube or reinforced LMA, SV, or IPPV. Laser-proof tube if needed. Regular postop diclofenac + paracetamol. OSA precautions if indicated

Submandibular gland excision

Excision of blocked/diseased submandibular gland

45–60

++

Supine, pad under shoulders, head ring

Small

RAE tube or reinforced LMA on opposite side, SV or IPPV

Tracheo-bronchial foreign body removal

Removal of inhaled foreign body using rigid bronchoscope, usually in child (see also [link])

20–30

NS

Supine, pad under shoulders

Nil

Deep inhalational anaesthesia using oxygen and halothane, allowing surgeon intermittent access. LA spray. Atropine useful to prevent bradycardia

Laryngoscopy in child

Examination of larynx in child, usually for recurrent stridor or aspiration

15–20

NS

Supine, pad under shoulders

Nil

Inhalational induction, LA spray to larynx. Either SV via rigid surgical laryngoscope (circuit connected to scope) or LMA with bars removed and fibreoptic laryngoscopy through it (ideal for small child and enables larynx to be viewed during emergence)

Direct pharyngoscopy

Examination of pharynx using rigid pharyngoscope

10–15

+

Supine, pad under shoulders

Nil

Check for reflux. Small (6.5–7) oral RAE tube secured on left, IPPV, mivacurium or intermittent suxamethonium. Risk of bleeding if biopsies done

Endoscopic stapling of pharyngeal pouch

Division of opening to pharyngeal pouch using staple gun endoscopically

15–20

+

Supine, pad under shoulders

Nil

Preoxygenate, avoid FM ventilation, small (6.5–7) oral RAE tube secured on opposite side, IPPV. NG tube at end and IV fluids as nil by mouth postop

Excision of pharyngeal pouch

Excision of pharyngeal pouch via external approach

45–60

++

Supine, pad under shoulders, head ring

Nil

Preoxygenate, avoid FM ventilation, small (6.5–7) oral RAE tube secured on opposite side, IPPV. Surgeon may want oesophageal bougie inserted to help recognise anatomy. Antibiotic cover, NG tube at end, and IV fluids as nil by mouth postop

Insertion of speaking valve (e.g. Provox®)

Insertion of speaking valve via tracheo- oesophageal puncture, following laryngectomy

15

+

Supine, pad under shoulders, head ring

Nil

Microlaryngoscopy tube inserted via tracheostomy, IPPV, mivacurium or intermittent suxamethonium, remifentanil or alfentanil to reduce CVS response

Pharyngo-laryngo-oesophagectomy

Resection of larynx, pharynx, and oesophagus for tumour of hypopharynx, using stomach pull-up or free jejunum transfer. Involves laparotomy ± thoracotomy

6–8hr

++++

Supine, pad under shoulders, head ring

Major, X-match 4–6U

No access to patient whatsoever! Prepare as for laryngectomy with all lines, plus double-lumen tube if doing thoracotomy. Consider epidural analgesia for laparotomy/ thoracotomy (using plain LA) with PCA morphine to cover remaining surgical sites. ICU mandatory postop; see also [link]

Notes:

1 Throat packs. National Patient Safety Agency alert. http://www.nrls.npsa.nhs.uk/resources/?entryid45=59853.

1 Mason RA, Fielder CP (1999). The obstructed airway in head and neck surgery. Anaesthesia, 54, 625–628.

1 Loadsman JA, Hillman DR (2001). Anaesthesia and sleep apnoea. British Journal of Anaesthesia, 86, 254–266.

2 Warwick JP, Mason DG (1998). Obstructive sleep apnoea syndrome in children. Anaesthesia, 53, 571–579.

1 Moiniche S, Romsing J, Dahl JB, Tramer MR (2003). Nonsteroidal antiinflammatory drugs and the risk of operative site bleeding after tonsillectomy: a quantitative systematic review. Anesthesia and Analgesia, 96, 68–77.