FIBREOPTIC INTUBATION: PRINCIPLES AND TECHNIQUES
- 1. FIBREOPTIC INTUBATION PRINCIPLES AND TECHNIQUES DR KAVITHA A/P KANDASAMY 07.03.2023
- 2. INTRODUCTION 01 SENSORY INNERVATION OF THE AIRWAY 02 TOPICAL ANAESTHESIA 03 APPLICATION TECHNIQUES 04 REGIONAL ANAESTHESIA TECHNIQUES 05 CONTENT SEDATION TECHNIQUES 06 PERFORMING AFOI 07
- 3. INTRODUCTION
- 4. Awake fibreoptic intubation (AFOI) is an essential skill in the management of a patient with a known difficult airway (who has previously required AFOI or other procedures and adjuncts aside from normal airway adjuncts for ventilation and intubation), or who has an anticipated difficult airway during the airway assessment preoperatively. It allows a flexible oral or nasal route to provide a clear visualisation of the vocal cords, and subsequent passage of an endotracheal tube into the trachea under direct vision.
- 5. It is difficult to give precise figures on the incidence of difficult airways due to a variety of reasons: population differences, operator skill variation, operator reporting, and an inconsistency in the definition of a difficult airway. In the general population, the approximate figures for the incidence of Cormack and Lehane laryngoscopy grades 3 and 4 is 10%, difficult intubation is 1%, and difficult bag mask ventilation is 0.08%–5%.
- 6. SENSORY INNERVATION OF THE AIRWAY
- 7. The upper airway is divided into: 1. nasal and oral cavities 2. pharynx 3. larynx The sensory innervation to the upper airway is supplied by: 1. trigeminal n. 2. glossopharyngeal n. 3. vagus n.
- 10. Nose • Entirely innervated by branches of the trigeminal n. • Septum and anterior parts of the nasal cavity are affected by the anterior ethmoidal n. (a branch of the ophthalmic n.) • The rest of the nasal cavity: greater and lesser palatine n. (branches of the maxillary n.) • The palatine nerves are relayed through the pterygopalatine ganglion, found in the pterygopalatine fossa, which is situated close to the sphenopalatine fossa, located just posterior to the middle turbinate.
- 11. Pharynx • Largely innervated by the glossopharyngeal n. Innervation of the whole pharynx, posterior third of tongue, the fauces, tonsils, and epiglottis is from the glossopharyngeal nerve.
- 12. Oropharynx • By branches of the vagus, trigeminal, and glossopharyngeal nerves • The posterior third of the tongue, vallecula, and anterior surface of the epiglottis: tonsillar n. (a branch of the glossopharyngeal nerve) • The posterior and lateral wall of the pharynx: pharyngeal n. (a branch of the vagus n.) • The tonsillar n. affects the tonsils • The anterior two thirds of the tongue: lingual n. (branch of the mandibular division of the trigeminal n.)
- 13. Larynx • By the vagus nerve. • Above the vocal cords (base of tongue, posterior epiglottis, aryepiglottic folds, and arytenoids): internal branch of the superior laryngeal n. (a branch of the vagus nerve) • For the vocal cords and below the vocal cords: recurrent laryngeal n. (a branch of the vagus nerve)
- 15. LA with vasoconstrictor properties > topical anesthesia of the nasopharynx (highly vascular) Available: 5% or 10% solution and in paste form Maximum recommended dose: 1.5 mg/kg Caution: CAD, HPT, and pseudocholinesterase deficiency Moffett’s solution (10 mls): mixture of 2 mL of 10% cocaine, 1 mL 1:1000 adrenaline, 2 mL sodium bicarbonate, and 5 mL sodium chloride. This is commonly used in rhinological procedures to provide local anesthesia, vasoconstriction, and decongestion. It is also used to topicalize the nasal mucosa to provide the optimal conditions for nasal intubations. cocaine
- 16. Most commonly used local anesthetic for airway topicalization The 4% solution and 10% spray are most often used Systemic absorption from topical application to the upper airways is lower than expected, so higher doses can be used than the recommended 2 mg/kg lidocaine
- 18. • McKenzie technique • Mucosal atomization device (MAD) • Spray from container • Local anesthetic soaked in ribbon gauze/ Cotton applicators • Oral gargle • Inhalation of nebulized lidocaine • “Spray as you go” via epidural catheter
- 19. The McKenzie technique uses a 20-g cannula attached to O2 bubble tubing via a three-way tap. The other end of bubble tubing is then attached to an O2 source, which is turned on to deliver a flow of 2–4 L/min. As the LA is slowly administered via a 5- mL syringe attached to the top port of the cannula, a jetlike spray effect is seen, which greatly increases the surface area of the local anesthetic and allows directed topicalization of the nasal and oral mucosa
- 20. Commercially available mucosal atomizers allow a similar mistlike effect as seen with the McKenzie technique by just attaching them to the end of a syringe. These are available for nasal and oral applications.
- 21. Apply long cotton-tipped applicators for 5 mins i) Inferior turbinate: Along the inferior turbinate to the posterior nasopharyngeal wall ii)Middle turbinate: Cephalad angulation along meddle turbunate to mucosa covering the spehnoid bone :.Anaesthetize the Sphenopalatine Ganglia iii)Superior turbinate: Along the superior turbinate, resting against the cribiform plate and posterior nasopharyngeal wall :.Anaesthetize the anterior ethmoid nerve • Drugs: Lignocaine with Phenylephrine (co- phenylcaine- lig 5% + phenyl 0.5%/ Lignocaine with Adrenaline/ Cocaine 4% (max 200mg in adult) 5 mls • Position: 30 degree elevated • Add: NPA lubricated with 2-5% of lignocaine jelly
- 22. • The oral cavity can be topicalised using 2% lignocaine viscous that is swished around in the mouth for a period of 5–10 min.
- 23. Adding approximately 5 mL of 4% lidocaine to a nebulizer, then delivering it with oxygen for up to 30 mins is a safe and noninvasive way to topicalize the airway all the way down to the trachea. It is well tolerated and is a useful technique to topicalize the whole airway. It also allows the topicalization of patients with limited mouth opening, where atomizers cannot be passed into the mouth to topicalize the oropharynx.
- 24. • The vocal cords can also be sprayed directly with LA using the spray-as-you-go (SAYGO) technique. • Here, the distal end of a 16-gauge epidural catheter is cut 3 cm from the end and then fed through the working channel of a fiberscope. • The Luer lock connector is connected to the proximal end of the catheter and then attached to a 5-mL syringe prepared with 4% lidocaine. • The distal end should protrude out of the fiberscope, so that the tip is just visible. The LA is then dripped onto the vocal cords prior to the fiberscope being introduced into the trachea. • This reduces patient discomfort and coughing when the fiberscope and endotracheal tube are introduced into the trachea.
- 26. Glossopharyngeal Nerve Block Technique: Mucosa at caudal aspect of posterior tonsillar pillar (palatopharyngeal fold) Position: - Patient sit facing anaesthetist, with mouth open - Anaesthetist stand opposite to side to be blocked Use tongue blade: push tongue away fr posterior tonsillar pillar creating a U-shaped gutter at floor mouth, betw tongue & palato-pharyngeal arch, aiming at the cul-de-sac of gutter Using 25G Spinal Needle, aspirate and inject 2mls 2% lignocaine - if air: withdraw superficially - if blood: redirect medially
- 27. Superior Laryngeal Nerve Block Patient position: supine with head slightly extended Technique i) Identify cornu of hyoid bone: (trace outward from thyroid notch, along upper border of thyroid cartilage) ii) Nondominant hand fingers: displace the hyoid bone with contralateral pressure Bring internal branch of superior laryngeal nerve towards anaesthesiologist thumb: appreciate carotid artery pulsation and displace it deep iii) Dominant Hand - Use 25G Needle: (i) (aim antero-infero-medially) Insert and hit lateral aspect of cornu of hyoid bone (ii) Walk needle 1-2mm downwards and towards midline till a ‘give’ felt, pierce thyro-hyoid membrane (iii) Aspirate and inject 2mls Lignocaine 2% - air: likely in the larynx: needs to be retracted - blood: vessels, maybe carotid a.: re-attempt procedure
- 28. Recurrent Laryngeal Nerve Block Patient position: supine with head hyperextended Technique: i) Locate cricothyroid membrane midline of neck: palpate thyroid prominence and feel caudally spongy fibromuscular band between thyroid and cricoid cartilages ii) 20G angiocath on 10mls syringe with 4mls 4% lignocaine: - pass perpendicular to axis of trachea, pierces the membrane - advance needle with syringe continously aspirated till air freely aspirated - then withdraw needle and leave cathether in situ iii) Patients asked to take a deep breath and then exhale focefully. At the end of expiration, administer 4mls of 4% lignocaine - patient will usually first inhale then forcefully cough Spread lignocaine over the trachea * note: direct blockage of recurrent laryngeal nerve is contraindicated ‘.’ May results in upper airway obstruction since it innervates all muscle of the larynx except cricothyroid muscle
- 30. Ideal sedation conditions: • Anxiolysis • Amnesia • Analgesia • Suppression of gag and cough reflexes • Easily titratable • Minimal respiratory side effects • Rapidly reversible
- 31. Examples of sedation techniques. • Boluses of benzodiazepines (eg, diazepam, midazolam) • Boluses of opioids (eg, fentanyl, alfentanyl, morphine) • Boluses of α2 agonists (eg, clonidine, dexmedetomidine) • Boluses of anesthetic agents (propofol, ketamine) • Combination of agents (eg, benzodiazepines and opioids) • Intravenous infusion (propofol, remifentanil, dexmedetomidine) • Combination of intravenous infusions (propofol and remifentanil)
- 32. AFOI can be an unpleasant experience for the patient, even if thorough topicalization of the airway has been done. The aim: patient to tolerate the procedure & optimal intubating conditions. Various techniques, the priority is to avoid oversedation of the patient. Two drugs are becoming increasingly popular and have growing evidence to support their use for conscious sedation: remifentanil and dexmedetomidine. Remifentanil is an ultrashort-acting opioid. Dexmedetomidine is a highly selective α2 agonist.
- 33. Remifentanil • Adv: provide good intubating conditions, is well tolerated, and has high patient satisfaction scores • Dis: high incidence of recall when used as a solo agent. Best results are seen when a TCI technique is used Dexmedetomidine slow bolus over 120 minutes followed by an infusion. • Adv: cooperative sedation, antisialagogue effects Level 1 evidence to support its use for good intubating conditions, patient tolerance & patient satisfaction Benzodiazepines combination with an opioid as intermittent boluses • Dis: intermittent boluses are associated with overshooting There is a risk of oversedation and apnea
- 34. Propofol intermittent boluses or as an infusion • Adv: Both techniques have been shown to be safe and well tolerated by patients. There is now increasing popularity of administering propofol as a TCI, either as a sole agent or in combination with remifentanil. Whichever technique is used, it is important to maintain a balance of an appropriate level of sedation and avoidance of underdosing or overdosing Propofol + Remifentanil TCI • Adv: Proven to be safe with consistent pharmacodynamic effects with more predictable level of sedation
- 36. PERFORMING AFOI
- 37. • Airway assessment • Physcological preparations • Pharmacological preparations • Preparation of equipment and personnel • Monitoring • Intubation
- 38. Airway assessment • All intubations are potentially difficult, but some are more difficult than others.Elicit the history of possible airway difficulty in the past. • The airway can be rapidly assessed,even in an emergency situation.
- 39. Psychological preparations • Every patient admitted to hospital goes through a complex series of feelings, most important among them being the feeling of anxiety and fear of the unknown,resulting in varying degrees of discomfort. • Winning the patient's confidence and cooperation is particularly important when endotracheal intubation is planned in the awake state. It is the first step towards making awake intubation under topical anaesthesia an acceptable option. The anaesthesiologist must describe to the patient in a careful and unhurried manner. • A written informed consent detailing the entire procedure.
- 40. Pharmacological preparations • Use of antisialogogues ensures a relatively dry field that facilitates good visibility during flexible fibreoptic-aided intubation. By reducing salivary secretions, it also ensures that local anaesthetic agents used for topical anaesthesia do not get diluted or suctioned out along with salivary secretions. A dry field ensures better quality of topical anaesthesia by allowing the local anaesthetic to act on the mucosal surfaces in appropriate concentrations. • Vasoconstriction of the highly vascular mucosa in the nose and nasopharynx.
- 41. Preparation of equipment and personnel • All operating suites should be geared to deal with an anticipated or unanticipated difficult airway,should be familiar with a well-rehearsed algorithmic approach that they will follow by reflex. Two heads (and four hands) have a greater chance of succeeding, especially when the going gets tough. • A range of oro/nasopharyngeal airways, assortment of ETT of various sizes, the entire family of LMA (including LMA-Classic, Intubating-LMA and ProSeal LMA), other supraglottic airways, different types of laryngoscope blades/handles, lighted stylet, rigid/flexible fibreoptic laryngoscopes, malleable stylets, tube exchangers, and a surgical airway kit.
- 43. Jun 13, 2022 An illustration of the awake tracheal intubation guidelines pu blished by the Difficult Airway Society. This demo uses a video bronchoscope on a volunteer and trie s to highlight the main techniques required to do this in a a s afe and comfortable manner.
- 44. THANK YOU
Editor's Notes
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