- Laryngoscopy – Medical procedure for viewing vocal folds (vocal cords) & glottis.
- Instrument used – Laryngoscope.
Macintosh type (MH-11):
- Most commonly used type.
- Has curved blade.
- Has straight blade
- Useful in difficult intubations.
- Contains fibreoptic channel visualizing laryngeal inlet directly.
- Got a movable tip.
- Has straight blade.
- Used for neonates.
Oxford infant blade:
- Used for infants
- To facilitate tracheal intubation during GA or cardiopulmonary resuscitation.
- Diagnostic or therapeutic procedures on larynx or other upper parts of tracheobronchial tree.
- Direct visualization of larynx & hypopharynx.
- An indirect visualization of larynx & hypopharynx.
- Done by use of mirrors & light source at the back of the throat. (Image of larynx seen in mirror).
- Laryngoscope is combined with operating microscope.
- Started by Kleinsasser.
- Provides excellent exposure of larynx to perform laryngeal microsurgeries (vocal cord cyst/nodule removal).
- Done in apnea with intermittent facemask inflation.
- Inflation – Prevents hypoxemia & maintains inhalation anesthesia.
- Usage of guard: Protects loose filled/capped teeth (especially upper incisors).
Components of direct laryngoscopy:
Optimal head & neck position:
- Obtained by neck flexion, mivacurium & atlantooccipital joint extension.
- Done by putting a small pillow under the occiput.
Optimal muscle relaxation:
- Allows greatest exposure of larynx.
- Prevents glottic closure.
- DOC – Succinylcholine for rapid (emergency) intubation.
- Rocuronium, mivacurium & rapacuronium – Sch alternatives.
Optimal laryngoscope blade
- Inserted from patient’s right side of mouth.
- This prevents tongue blocking the larynx view.
- Blade tip is advanced alongside tongue towards midline.
- In epiglottis, tip is inserted firmly but not forcibly into vallecula.
- Hence, lifting epiglottis base forward to reveal cords.
- Curved laryngoscope blade preferred– Causes less stretching of faucial pillars than a straight blade.
Optimal external laryngeal manipulation:
- Best maneuver – BURP (backward, upwards & to right pressure).
- Backward & lateral pressure on larynx by anesthetist or assistant may help bring cords into view.
Optimal use of introducer (bougie):
- Gum elastic bougie (introducer) with coude tip – Single most useful aid for difficult direct laryngoscopy.
- Introduced into trachea & used as guide to railroad tracheal tube.
- Goal – To position endotracheal tube end @ 5 ± 2 cm proximal to trachea bifurcation i.e., carina.
- Done with head & neck in neutral position.
- Neck flexion causes 2 cm ascent.
- Correct position of tip: 3 ± 2 cm from carina with flexed neck & 7 ± 2 cm from carina with extended neck.
- Cormack & Lehane grading:
- Direct laryngoscopy grading for amount of larynx exposed.
- Occur due to interruption of protective reflexes.
- Hypertension, tachycardia, cardiac arrhythmias, cardiac arrest, reflex bradycardia.
- Treated by fentanyl, LA lignocaine spray, CCB (diltiazem).
- CNS: Increases ICT, cerebral activity, blood flow & metabolic rate.
- Eyes: Increases intraocular pressure (>40mm Hg)
- Respiratory: Laryngospasm & bronchospasm.
- Acute laryngeal spasm during indirect laryngoscopy is seen in Acute epiglottitis.
- During laryngoscopy and endotracheal intubation, the laryngoscope is lifted upwards levering over the upper incisors maneuver is not performed.
- Anesthesia used in microlaryngoscopy is Pollard tube with infiltration block.
- In a direct laryngoscopy Cricothyroid, Lingual surface of epiglottis & Arytenoids can be visualized.
- Hidden areas of larynx viz. infrahyoid epiglottis, anterior commissure, ventricles and subglottic region and apex of pyriform fossa are difficult to visualize by indirect laryngoscopy.
- Microlaryngoscopy was started by Kleinsasser.
- The procedure that should precede microlaryngoscopy is Rhinoscopy.
- Laryngoscopy showing diagnosis of multiple juvenile papillomatosis of the larynx should be followed by Microlaryngoscopic surgery
- Intraocular pressure rises in Intubation & laryngoscopy.
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