awake fiber-optic bronchoscopy
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DR. MANISHA MODERATORDR. MAMTA SHARMA
Introduction Providing anesthetic care to the patient with a difficult
airway provokes anxiety as well as interest in anesthesiologists mind. In the situation where the airway must be controlled
and anesthesia must be delivered via an endotracheal route, intubation through the use of a flexible fiberoptic bronchoscope is a commonly chosen method.
To visualize and to observe the lesions of the tracheobronchial tree To collect specimen for biopsy and culture (e.g. by curettage or brushing
For therapeutic purpose:
For Endotracheal Intubation To remove foreign body in the tracheobronchial tree by forceps or baskets To remove malignant tumors by laser (laser photoresection) To frozen surface skin lesion (e.g. cryotherapy) To destroy malignant tumors by radiation (e.g. brachytherapy), by electricity (e.g. electrocautery) or by chemicals (e.g. photodynamic therapy)
WHY WE ANESTHESIOLOGISTS NEED ITDifficult airways !!1. 2. 3. 4. 5. 6. 7. 8.
small mouth Receding jaw Reduced mouth opening due to radiation therapy Jaw fracture Previous head and neck surgery Difficulty in neck extension due to prior cervical fusion or advanced osteoarthritis Neck extension is contraindicated in patients with unstable cervical spines due to fx., rheumatoid arthritis, Down syndrome, etc. Patients who cannot be intubated using direct laryngoscopy due to anatomical variations, even though their airway exam appears normal.
Biopsy port with cap
Video connection Insertion tube
Working channel Light transmitting glass fiber bundle
Control knobLight source and camera
Viewing glass fiber bundle
WORKING PRINCIPAL Transmission of light in bronchoscope is based on total
internal reflection When light is incident upon a medium of lesser index of refraction (ni>nt), the ray is bent away from the normal. such reflection is commonly called "internal reflection" The exit angle will then approach 90 for some critical incident angle c, and for incident angles greater than the critical angle there will be total internal reflection For fiberoptic bronchoscope, images are brought back to eyepiece using this principle
Innervation of the Airway1. 2.
The airway is divided into: Nasal cavities Oral cavities Pharynx ( consisting of the naso-, oro-, and hypopharynx) Larynx Trachea
Innervation of the Airway Nose - The nasal cavity is entirely innervated by fibers carried by branches of the trigeminal nerve. PHARYNX- Mainly innervated by glossopharyngeal nerve LARYNX 1. The superior laryngeal nerve dividing into internal and external branch 2. Recurrent laryngeal nerve
The airway reflexes The aforementioned nerves participate in several
brainstem-mediated reflex arcs. 1.gag reflex triggered by mechanical and chemical stimulation ofareas innervated by the glosso-pharyngeal nerve, and the efferent motor arc is provided by the vagus nerve and its branches to the pharynx and larynx.
2.glottic closure reflex elicited by selective stimulation of thesuperior laryngeal nerve, and efferent arc is the recurrent laryngeal nerve. exaggeration of this reflex is called laryngospasm.
3.cough the cough receptors located in the larynx and tracheareceive afferent and efferent fibers form the vagus nerve.
Preprocedural preparation of the patient
Check emergency medication/ equipmentExplanation Sedation Anti-sialagogue Remove artificial denture
Explanation1. The reasons for proceeding with an awake fiberoptic
intubation 2. The potential complications 3. The type of airway anesthesia that will be provided 4. Possible alternatives to the proposed anesthetic
Sedation Adequate sedation is important and advantageous in
both the anesthetizing of the airway as well as during the intubation. A calm and comfortable patient is much more likely to cooperate with the anesthesiologist during the procedures. Agents used to produce sedation generally fall into 2 group: benzodiazepines and opioids.
Anti-sialagogues Decreasing oral secretions will aid in the placing and
effectiveness of topical agents. Fiberoptic intubation is much easier if excess secretions are not obscuring the operators view. For these purpose, glycopyrrolate is the one that is most commonly used due to its lack of CNS effects and relatively lesser likelihood of producing tachycardia.
Commonly Used Medications and DosagesWith Their Reversal AgentsMedication Atropine Glycopyrrolate Dosage and Route 0.51 mg IV, IM Effect Antisialogogue Reversal Agent N/A N/A
0.20.4 mg IV, IM Antisialogogue
Loading dose: 1 mcg/kg/min over Dexmedetomid 10 min ine Infusion: 0.20.7 mcg/kg/min
0.54 mg IV10100 mcg IV 1001000 mcg IV
There are three most often used local anesthetic with or without the use of vasoconstrictors: 1. Cocaine 2. Benzocaine 3. Lidocaine +/- vasoconstrictors
Goals of anesthesia before FOB To decrease the mucosal senstivity
To obtund the airway reflexes
Anesthesia For Awake Intubation Anesthesia of the Nasal Mucosa and Nasopharynx
(Nasal Intubation) SPHENOPALATINE GANGLION and ETHMOID NERVE Anesthesia of the Mouth, Oropharynx and Base of Tongue GLOSSOPHARYNGEAL NERVE BLOCK SUPERIOR LARYNGEAL NERVE BLOCK Anesthesia of the Hypopharynx, Larynx and Trachea RECURRENT LARYNGEAL NERVE BLOCK
Anesthesia of the Nasal Mucosa and Nasopharynx Drugs: 4% Lidocaine with epinephrine (or cocaine is a
4% solution max. 200 mg in adult), or mixture of Lidocaine 3%(max dose 4-5mg/kg without epinephrine and 6-7 mg/kg with epinephrine) and Phenylephrine 0.25% Patient Position: Patient is most comfortable when head of
bed is elevated approximately 30 degree Technique: *Application of long cotton-tipped applicators or
wide cotton string threaded pledgets soaked in the local solution
one applicator is placed along the inferior turbinate to
the posterior nasopharyngeal wall a second applicator is placed in a cephalad angulation along the middle turbinate, back to the mucosa covering the sphenoid bone (most important ) a third applicator may be placed along the superior turbinate, resting against the cribiform plate and posterior nasopharyngeal wall, providing anesthesia to the anterior ethmoid nerve applicators are then left in place for 5 minutes, and the pledgets for 2-3 minutes nasal airways, in increasing sizes, can be lubricated with Lidocaine 2-5% jelly, and passed into the nostril being intubated for additional patient comfort
Anesthesia of the Mouth and Oropharynx Drugs: Cetacaine spray (mix of 14% Benzocaine and
2% Tetracaine), Lidocaine spray 10% ( max 200mg or 20 spray), Lidocaine gel 2-5%, Viscous lidocaine 2%, Tetracaine .5% soln, Lidocaine 4% soln. Patient Position: Supine Techniques: 1. Non-invasive 2. invasive
NON INVASIVE TECHNIQUES Lidocaine gel can be placed on tongue blade and patient
"sucks" on this for several minutes 4cc of 4% Lidocaine or 0.5% Tetracaine can be placed in a nebulizer. The patient then inhales the nebulized local anesthetic for 5-7 min, or the tongue and posterior pharynx are sprayed with the atomizer Cetacaine spray (tetracaine and benzocaine combination) may also be used to provide anesthesia to the tongue and posterior pharynx.I. II.
toxic dose of benzocaine - 100 mg toxic dose of Tetracaine - 100 mg (but toxicity has been reported at 40 mg).
Viscous lidocaine 2-4 ml may also be used as a gargle
(swish and swallow) for approx. 30 sec.
INVASIVE TECHNIQUES GLOSSOPHARYNGEAL NERVE BLOCK is performed
when topical techniques are not completely effective in obliterating the gag reflex. This is performed with the anesthetist standing contralateral to the side to be blocked and the patients mouth wide open The palatopharyngeal fold (posterior tonsillar pillar) is identified and a tongue blade, held with the non-dominant hand, is introduced into the mouth to displace the tongue medially (contralateral side) creating a gutter between the tongue and the teeth A 25 G spinal needle is inserted into the membrane near the floor of the mouth at the base of the cul-de-sac and advanced slightly (0.25-0.5 cm).
aspiration test is performed If air is aspirated, the needle has passed through the
membrane (through and through). If blood is aspirated, the needle is redirected more medially. 2 ml of 1% Lidocaine can be injected into the anterior tonsillar pillar 0.5 cm lateral to the base of the tongue blocks the lingual branch This block is painful, may result in a persistent hematoma. Methemoglobinemia occurs when the ferrous molecule in
hemoglobin is changed to its ferric state with essentially ionic bonds by oxidation
SUPERIOR LARYNGEAL NERVE (SLN) BLOCK Drugs: 2-4 ml of Lidocaine 1% or 2% lidocaine, with or
without epinephrine Patient Position: Supine, with head slightly extended
Patient is asked to open the mouth widely, and the
tongue is grasped using a guaze pad or tongue blade. A right angle forcep (e.g., Jackson-Krause) is covered with anesthetic-soaked guaze and is slid over the lateral tongue and down into the pyriform sinuses Cotton swabs are held in place for 5 minutes
Depicting the Vagus
nerve branching into Superior Laryngeal and Recurrent Laryngeal nerve. Note the insertion of Superior Laryngeal Nerve into ThyroHyoid Membrane
Tracheal anatomy depicting Superior Laryngeal Nerve with ascending and descending branches.
Invasive position - ipsilateral side of the neck Technique The cornu of the hyoid bone is palpated transversally with
the thumb and the index finger on the side of the neck immediately beneath the angle of the mandible and anterior to the carotid artery. To facilitate its identification, the hyoid bone is displaced toward the side being blocked. One hand displaces the carotid artery laterally and posteriorly. With the other hand, a 22 or 23 guage - 25 mm needle is "walked off" the cornu (cartilage) of the hyoid bone in an anterior caudad direction, aiming in the direction of the thyroid ligament, until it can be passed through the ligament.
Laryngeal Nerve Block showing displaceme nt technique
At a depth of 1-2 cm, 2 ml of 2% lidocaine with epinephrine is
injected (after negative air and blood aspiration) into the space between the thyrohyoid membrane and the pharyngeal mucosa. An additional 1 ml is injected as needle is withdrawn. The block is repeated on the other side.
Technique Tips! Firmly displace the hyoid bone towards the side to be blocked,
even if it causes the patient some minor discomfort. Exercise caution - not to insert the needle into the thyroid cartilage, injection of local anesthetic at the level of vocal cords may cause edema and airway obstruction. If air is aspirated, laryngeal mucosa has been pierced, and the needle needs to be retrieved. If blood is aspirated (superior laryngeal artery or vein), the needle needs to be redirected more anteriorly. Pressure should be applied to avoid hematoma formation
RECURRENT LARYNGEAL NERVE BLOCK (TRANSTRACHEAL or TRANSLARYNGEAL BLOCK) 3-4 ml of Lidocaine 4 % is used. Also, 1% or 2% lidocaine,
with or without epinephrine. Patient Position: Supine, with neck hyperextended (or pillow removed and extended) Technique place index and third fingers of the non-dominant hand in the space between the thyroid and cricoid cartilages (identifying the cricothyroid membrane) The trachea can be held in place by placing the thumb and third finger on either side of the thyroid cartilage. The midline should then be identified and injected lightly to create a local skin wheal (using a 22-guage or smaller needle).
of fingers to identify the midline of the cricothyroi d membrane
A 10 ml syringe containing 4% lidocaine (or other
desired concentration), is mounted on a 22-guage, 35 mm plastic catheter over a needle, and is introduced into the trachea. The catheter is advanced into the lumen, midline thru the cricothyroid membrane, at an angle of 45 degrees, in a caudal direction a loss of airway resistance and aspiration of air confirms placement, and the needle is removed from the catheter this usually cause patient to first inhale to catch his or her breath and then forcefully cough, spreading the lidocaine over the trachea This area is nearly devoid of major vascular structures
of the needle for the Transtrach eal or Recurrent Laryngeal Nerve Block.
spread of local anesthetic with coughing
Technique Tips! If a regular needle is used to inject (rather than a catheter),
the lidocaine is injected rapidly and the needle is removed immediately!!! Surrounding structures, including the posterior tracheal wall can be damaged if the needle is not stabilized during injection of the local anesthetic and then be removed immediately! The catheter should bet in place until the intubation is completed for the purpose of injecting more local anesthetic, if necessary, and to decrease the likelihood of subcutaneous emphysema patient is then asked to take a deep breath and then asked to exhale forcefully. At the end of the expiratory effort, 3-4 ml of local anesthetic solution is rapidly injected into and over the back of the trachea.
COMPLICATIONS Gastric Aspiration
-decrease the risk, by decreasing risk of coughing and gag reflex duringintubation
Risk of Coughing
-Contraindicated in patients diagnosed with an unstable neck, Vascular injury Structural injuries -posterior tracheal wall and vocal cords can be damaged, especially if theneedle is not stabilized during injection of the local anesthetic, or not removed immediately
Systemic toxicity Intravascular injection
Equipment setup and preliminary checks Connect and switch on the light-source and suction. Check
the patency of working channel by instilling saline. Clean the tip of the scope with a cotton gauze. Focus the scope using the diopter ring while looking through the view finder at some fine printed matter or palmer crease. Check the suction by pressing the suction knob and sucking normal saline from a bowl with the tip of the scope dipped into the saline. Thread the appropriate enotracheal tube over the scope Establish standard monitoring and Intravenous access. Watch out for absolute or relative contraindications like coagulopathy, refractory hypoxemia, unstable hemodynamics, myocardial infarction in last 6 weeks
Handling the scope Right handed person will find it easier to advance and maneuver the
main cord with the right hand and use the left hand to hold the handle with the index finger over the suction knob and the thumb over the lever for controlling the scope tip. the 12 Oclock position during insertion. This cursor describes the plane of movement of the tip of scope.lever down moves the tip upwards (anteriorly) and pushing it up angulates the tip downwards (posteriorly).
The black cursor (triangular marker) in the viewfinder should be at
The lever and scope tip moves in opposite directions; pushing the
In order to angulate the tip to the left or right, the scope is rotated so
that the cursor moves to 9 Oclock or 3 Oclock position respectively and then the lever is pushed down.
The entire procedure requires only three movements:
flexion of the tip of the scope along the plane of the cursor, rotation of the entire scope to the left or right and advancement or withdrawal of the scope. The goal is to keep the point of interest (uvula, epiglottis, tracheal opening) in the centre of the field.If the point of interest is at the bottom of the field and you want to move it up towards the centre, move the lever up. ii. If the point of interest is at the right edge of the field and you wish to center it, rotate the wrist to right so that the cursor moves to 3` O clock position then press the lever down. iii. For centering a point of interest located at the left edge of the field, rotate the wrist to the left so that the cursor moves to 9` O clock and then move the lever down.i.
Whenever the point of interest is at the centre of the field
the scope can be advanced with the right hand.
TECHNIQUE The procedure can be done either standing at the
head-end facing the patients feet or standing on the side facing the patients face. Stand tall to avoid bending the main cord that may
damage fiber optic bundles. The assistant is instructed regarding the application of
jaw thrust or head extension if required.
Oral approach: An intubating airway like the Ovassapian airway or a mouth
guard is inserted to protect the main cord from being damaged by the patients teeth. The lubricated scope is inserted down the airway using the right hand. The right thumb, index and middle fingers hold the distal end of the scope for insertion while the little finger rests on the patients face for stability. The uvula is visualized and the scope is maneuvered beneath it. Once beyond the uvula, angulate the tip anteriorly by pushing the lever down and advance until the epiglottis comes into view. This sharp angulation at the uvula makes the oral FOB difficult as compared to the nasal approach where a gentle curve is encountered.
Nasal approach: The tip of the nose is elevated and the scope is
introduced through the more patent nostril. It is inserted along the inferior turbinate. Stay in the centre of the lumen and avoid scraping the
mucosa that may precipitate bleeding. After entering the nasopharynx gently angulate the
scope anteriorly and advance to visualize the epiglottis
APPROACH AFTER EPIGLOTTIS VISUALIZATION Advance the scope below the epiglottis to visualize the glottic
opening. If passage beneath the epiglottis is difficult ask the assistant to extend the head of the patient or execute jaw thrust. Keep the vocal cords in the centre of the field by up-down angulation or clockwise, counter clockwise rotationof the scope. If anatomy is lost at any stage, withdraw the scope until the anatomy becomes identifiable again. When withdrawing the scope, remove finger from the lever that controls the tip.
The scope commonly impinges at the anterior
commissure or the anterior laryngeal wall. Angulate posteriorly while advancing between the cords to enter the trachea. The trachea is recognized by the C shaped cartilages anteriorly (12 Oclock position). Keep the tracheal opening in the centre of the field and advance the scope until the carina comes into the view. Endotracheal tube (previously loaded over the FOB) is threaded into the trachea and FOB is withdrawn keeping the tip straight to avoid damage
Care of the FOB Immediately after removal from patient, exterior of FOB
should be wiped with disinfectant All channels should be flushed with water or an enzymatic detergent Fiberscope should be immersed in enzymatic solution with water resistant cap over video connector Allow to soak for 2-5 min and then cleaned and rinsed with sterile water / tap water and the alcohol Endoscope should be hung vertically to allow any remaining fluid to drain out Disinfectant used gluteraldehyde / hydrogen peroxide Gas sterlization can be used
Topicalization is the simplest method for anesthetizing the airway. Local anesthetic can be sprayed directly onto the desired mucosa. Nebulization of lidocaine 24% via face mask or oral nebulizer for 1530 minutes can achieve highly effective anesthesia of the oral cavity and trachea for intubation.
Atomization is ideal for airway topicalization during nasotracheal intubations.
Density of anesthesia is variable and often requires supplementation tofacilitate intubation.
Anesthetic-soaked cotton can be applied to targeted mucosal surfaces for
515 minutes to effect selective blockade of underlying nerves.
Vasoconstrictors such as epinephrine (1:200,000) or phenylephrine (0.05%) can be added to the solution to reduce mucosal bleeding.
Adequate time allocation is needed to achieve optimal conditions.
Ask the patient to protude the tongue. The assistant
will hold it gently with the gauge and pull gently out. This will help elevate the epiglottis
Classical indication for nasal route Restricted mouth opening
Short and thick neck
Tumor/mass in oral cavity