ENT Flashcards
GENERAL ENT ISSUES – ENT PATHOLOGY (2) AND SURGICAL ACCESS (5)
Presenting pathology may: • Produce airway obstruction • Make access difficult or impossible. Surgeons working in or close to the airway can: • Displace or obstruct airway equipment • Obscure the anaesthetist’s view of the patient • Limit access for the anaesthetist during operation • Produce bleeding into the airway (intra- and postoperatively). • Cause eye compression – protect from pressure and cover with padding
WHICH AIRWAY FOR WHICH ENT PROCEDURE?
Negotiate with individual surgeon based upon location of pathology as well as patient factors re risk of LMA vs ETT. Ring, Adair, Elwyn (RAE) ETT provide least intrusion into surgical field and can be oral (south) or nasal (north). Use oral for nasal work and most oral work, and a nasal tube if greater oral access if required. Reinforced LMA provides adequate protection against aspiration of blood/debris and reduces complications of intubation/extubation but greater limitation of surgical access and displacement during surgery can lead to catastrophic aspiration.
LOCATION OF BLOOD POOLING DURING ENT SURGERY
Suction and pack removal essential prior to extubation. Blood accumulates within the nasopharynx behind the soft palate so suction with Yankauer behind the uvula with neck flexion
BENEFITS/RISKS/CONTRAINDICATIONS OF DEEP EXTUBATION IN ENT PATIENTS
Laryngospasm can occur especially in children due to instrumentation or accumulation of blood around larynx. Avoided by extubating either awake or deep. Light extubation associated with greater amounts of coughing and cardiovascular disturbance while deep extubation associated with greater respiratory complications. Contraindications to deep extubation: lack of adequately trained PACU staff, difficult BMV, difficult intubation, residual curarisation or high aspiration risk (full stomach/pregnant/obese). Deep extubation is achieved by having the patient spontaneously ventilating, maintaining dose of volatile, 100% oxygen, suctioning/pack removal, Guedel insertion, position left lateral-head down (“tonsil position”), ensure respiration regular then extubate. Turn off volatile and maintain in left lateral head down position until airway reflexes have returned.
What is a throat pack and why are they useful? What precautions need to be taken?
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. Particularly useful during nasal operations where bleeding can be substantial and is not cleared during surgery. **Always perform laryngoscopy prior to extubation.** The pack must be removed before extubation, as it can lead to catastrophic airway obstruction if left. Systems to ensure removal include: • Tie or tape the pack to the ETT. • Place an identification sticker on the ETT or patient’s forehead. • Include the pack in the scrub nurse’s count.
Risks vs benefits of ETT and LMA for ENT work
ETT: Advantages: secure airway with good surgical access. Disadvantages: extubation and stormy emergence → bleeding and soiling; risk of airway trauma; may require NMB. LMA: Disadvantages: greater limitation of surgical access and displacement during surgery can lead to catastrophic aspiration. Advantages: easy insertion and if properly placed, limits soiling of subglottis cf an ETT. Better emergence.
What is in co-phenylcaine forte and maximum dose?
Consists of pump-actuated topical spray containing lignocaine HCl 5% (50mg/ml) and phenylephrine HCl 5mg/mL. Contains sodium metabisulfite. 1 spray = 0.1mL = 5mg lignocaine and 0.5mg phenylephrine. Max dose is 7mg/kg lignocaine with vasopressor so approximately 1 spray per kg total is maximum dose; however product information advises maximum 5 sprays per nostril in an adult and 1 spray per nostril in a small child. Avoid food/drink due to aspiration risk for at least 2 hours.
Maximum dose of topical cocaine and contraindications to its use
Maximum dose 1.5 mg/kg up to 200mg and toxic dose is 3mg/kg (NB easy to exceed maximum dose when administered using soaked gauze). 70kg = 105 mg = 10ml of 1% solution. Contraindications: • Use of MAOI within 14 days • Cardiac catecholamine sensitivity (arrhythmias, HTN) • ↑ QT syndrome • Damaged mucosa → ↑ risk systemic toxicity
How can pre-operative airway obstruction be safely managed?
Factors making airway obstruction worse: lying flat, instrumenting larynx and GA induction. Avoid IV induction or neuromuscular blockade. No single technique is universally safe. - Laryngoscopy under deep inhalational anaesthesia whilst spontaneously ventilating (only realistic option in children with CPAP) - Awake topicalised fibreoptic intubation (may be difficult with stenotic procedures due to scope obstructing airway) - Awake tracheostomy under local anaesthetic
What equipment is required prior to induction of a pt with an airway obstruction?
Ensure full range of airway equipment available including different laryngoscopes, different sized tubes and cricothyroidotomy kit. Preparation for emergency cricothyroidotomy (preferred to tracheostomy as quicker, more superficial and less bleeding).
Anaesthetic technique for myringotomy/grommet insertion
o Supine with head ring o Can do with LMA o Check for recent URTI o Post-operative paracetamol/NSAID (not v painful) o Bradycardia due to vagal stimulation of tympanic membrane
Anaesthetic management of tonsillectomy/adenoidectomy
o Pre-op • Elicit hx of OSA or active infection • Topical LA on hands • Consent PR analgesia o Perioperative • Prepare for airway obstruction post induction – either insert Guedel or LMA once deep or intubate with uncuffed south Rae tube • IV access post induction (in case of bleeding) • Multimodal analgesia including opioid but NSAIDs controversial due to bleeding risk esp if given pre-op • Suction pharynx under direct vision (blind → ↑ bleeding risk) • Extubate left lateral or head down with Guedel and leave in this position until airway reflexes return • Adult tonsillectomy usually more painful o Post-op: • Signs of bleeding: continuous swallowing → return to OT • Educate parents re signs of bleeding if day case
Management of post-operative tonsillar bleeding (3 main issues)
o Usually greater losses than initially suspected due to swallowed blood o Get senior anaesthetic assistance due to following issues: • Hypovolaemia • Aspiration risk (fresh and swallowed blood) • Difficult intubation due to airway oedema/blood o Pre-op • Resuscitate with X-matched blood o Periop • RSI with anticipated difficulty • Inhalational induction head down/left lateral • Empty stomach with NGT • Extubate fully awake o Check Hb postop
Management of tympanoplasty/myringoplasty
o Reconstruction of perforated tympanic membrane using temporalis fascia o Perioperative: • Avoid coughing/vomiting – LA to larynx or NMB and IPPV; remifentanil infusion; antiemetics • Avoid N2O due to risk of graft lifting off • Sometimes facial nerve monitoring used (EMG electrodes on face detect nerve activity and audible monitor signals – hence argument for using remifentanil cf. NMB for middle/inner ear cases).
Anaesthetic issues for stapedectomy
o Bloodless field achieved by avoiding coughing and tilting head up to ↓ venous pressure; permissive hypotension (MAP 50-60) if healthy. Achievable using remifentanil infusion, IV labetalol 5mg increments or β blocker + vasodilator o Arterial line if unwell or vasodilators required o Routine antiemetic
